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Sample records for kamlet-taft solvent parameters

  1. Analysis of the Cybotactic Region of Two Renewable Lactone-Water Mixed-Solvent Systems that Exhibit Synergistic Kamlet-Taft Basicity.

    Science.gov (United States)

    Duereh, Alif; Sato, Yoshiyuki; Smith, Richard Lee; Inomata, Hiroshi

    2016-05-19

    Kamlet-Taft solvatochromic parameters (polarity, basicity, acidity) of hydrogen bond donor (HBD)/acceptor (HBA) mixed-solvent systems, water (H2O)-γ-valerolactone (GVL), methanol (MeOH)-GVL, ethanol (EtOH)-GVL, H2O-γ-butyrolactone (GBL), MeOH-GBL, and EtOH-GBL, were measured over their entire composition region at 25 °C using UV-vis spectroscopy. Basicity of H2O-GVL and H2O-GBL systems exhibited positive deviation from ideality and synergism in the Kamlet-Taft basicity values. The cybotactic region around each indicator in the mixed-solvent systems was analyzed with the preferential solvation model. Both H2O-GVL and H2O-GBL mixed-solvent systems were found to be completely saturated with mutual complex molecules and to have higher basicity than pure water because water prefers to interact with GVL or GBL molecules rather than with itself. Formation of H2O-GVL and H2O-GBL complex molecules via specific hydrogen bond donor-acceptor interactions were confirmed by infrared spectroscopy. In MeOH-GVL or MeOH-GBL mixed-solvent systems, MeOH molecules prefer self-interaction over that with GVL or GBL so that synergistic basicity was not observed. Synergistic basicity and basicity increase for various functional groups of ten mixed-solvent (water-HBA solvent) systems can be quantitatively explained by considering electrostatic basicity and a ratio of the partial excess HBA solvent basicity with the HBA solvent molar volume that correlate linearly with the preferential solvation model complex molecular parameter (f12/1). Analysis of the cybotactic region of indicators in aqueous mixtures with the preferential solvation model allows one to estimate the trends of mixed-solvent basicity.

  2. POLARITY AND HYDROGEN-BONDING OF AMBIENT TO NEARCRITICAL WATER: KAMLET-TAFT SOLVENT PARAMETERS. (R828130)

    Science.gov (United States)

    The perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Concl...

  3. Correlating solubility parameters and solvatochromic parameters with the self-assembly of poly(3-hexylthiophene) in mixtures of organic solvents

    Science.gov (United States)

    Gordon, Madeleine; Boucher, David

    2015-03-01

    We have studied the assembly and crystallinity of poly(3-hexylthiophene) (P3HT) (Mn ~ 28.2 kDa, regioregularity > 96 %, PDI ~ 1.3) in >100 binary solvent mixtures using UV-Vis absorption spectroscopy, and it is clear that the identity of the poor solvent used to drive aggregation has a significant impact on the structural order and crystallinity of the P3HT aggregates in solution. Here we report our findings using Hansen solubility parameters (HSPs), specifically the solubility distance vector, Ra, and the Kamlet-Taft solvatochromic parameters of the solvent mixtures to better understand the dominant solvent forces driving the self assembly of P3HT. We find that the directionality of the Ra vector provides a better measure of the crystallinity of the P3HT assemblies formed in the solvent mixtures than does the magnitude of the Ra vector. Our analysis of the Kamlet-Taft (α, β, π*) and ET(30) solvatochromic parameters reveals that the β parameter correlates best with the crystallinity of P3HT and that, in general, assemblies having higher structural order are formed in solvent mixtures with lower values of β.

  4. Electrochemical oxidation of substituted benzylamines in aquo-acetic acid medium: substituent and solvent effects

    Indian Academy of Sciences (India)

    A Thirumoorthi; K P Elango

    2007-07-01

    Electrochemical oxidation of nine para- and meta-substituted benzylamines in varying mole fractions of acetic acid in water has been investigated in the presence of 0.1 M sulphuric acid as supporting electrolyte. The oxidation potentials correlate well with Hammett’s substituent constants affording negative reaction constants. The correlation of potential values with macroscopic solvent parameters is non-linear suggesting that the operation of both specific and non-specific solvent-solvent-solute interaction mechanisms. Multiple correlation analysis of the experimental data with Kamlet-Taft solvatochromic parameters is employed.

  5. Rational Design of Molecular Gelator - Solvent Systems Guided by Solubility Parameters

    Science.gov (United States)

    Lan, Yaqi

    Self-assembled architectures, such as molecular gels, have attracted wide interest among chemists, physicists and engineers during the past decade. However, the mechanism behind self-assembly remains largely unknown and no capability exists to predict a priori whether a small molecule will gelate a specific solvent or not. The process of self-assembly, in molecular gels, is intricate and must balance parameters influencing solubility and those contrasting forces that govern epitaxial growth into axially symmetric elongated aggregates. Although the gelator-gelator interactions are of paramount importance in understanding gelation, the solvent-gelator specific (i.e., H-bonding) and nonspecific (dipole-dipole, dipole-induced and instantaneous dipole induced forces) intermolecular interactions are equally important. Solvent properties mediate the self-assembly of molecular gelators into their self-assembled fibrillar networks. Herein, solubility parameters of solvents, ranging from partition coefficients (logP), to Henry's law constants (HLC), to solvatochromic ET(30) parameters, to Kamlet-Taft parameters (beta, alpha and pi), to Hansen solubility parameters (deltap, deltad, deltah), etc., are correlated with the gelation ability of numerous classes of molecular gelators. Advanced solvent clustering techniques have led to the development of a priori tools that can identify the solvents that will be gelled and not gelled by molecular gelators. These tools will greatly aid in the development of novel gelators without solely relying on serendipitous discoveries.

  6. To gel or not to gel: correlating molecular gelation with solvent parameters.

    Science.gov (United States)

    Lan, Y; Corradini, M G; Weiss, R G; Raghavan, S R; Rogers, M A

    2015-10-07

    Rational design of small molecular gelators is an elusive and herculean task, despite the rapidly growing body of literature devoted to such gels over the past decade. The process of self-assembly, in molecular gels, is intricate and must balance parameters influencing solubility and those contrasting forces that govern epitaxial growth into axially symmetric elongated aggregates. Although the gelator-gelator interactions are of paramount importance in understanding gelation, the solvent-gelator specific (i.e., H-bonding) and nonspecific (dipole-dipole, dipole-induced and instantaneous dipole induced forces) intermolecular interactions are equally important. Solvent properties mediate the self-assembly of molecular gelators into their self-assembled fibrillar networks. Herein, solubility parameters of solvents, ranging from partition coefficients (log P), to Henry's law constants (HLC), to solvatochromic parameters (ET(30)), and Kamlet-Taft parameters (β, α and π), and to Hansen solubility parameters (δp, δd, δh), are correlated with the gelation ability of numerous classes of molecular gelators. Advanced solvent clustering techniques have led to the development of a priori tools that can identify the solvents that will be gelled and not gelled by molecular gelators. These tools will greatly aid in the development of novel gelators without solely relying on serendipitous discoveries. These tools illustrate that the quest for the universal gelator should be left in the hands of Don Quixote and as researchers we must focus on identifying gelators capable of gelling classes of solvents as there is likely no one gelator capable of gelling all solvents.

  7. Synthesis and evaluation of changes induced by solvent and substituent in electronic absorption spectra of some azo disperse dyes.

    Science.gov (United States)

    Mohammadi, Asadollah; Yazdanbakhsh, Mohammad Reza; Farahnak, Lahya

    2012-04-01

    Five azo disperse dyes were prepared by diazotizing 4'-aminoacetophenone and p-anisidine and coupling with varies N-alkylated aromatic amines. Characterization of the dyes was carried out by using UV-vis, FTIR and 1H NMR spectroscopic techniques. The electronic absorption spectra of dyes are determined at room temperature in fifteen solvents with different polarities. The solvent dependent maximum absorption band shifts, were investigated using dielectric constant (ɛ), refractive index (n) and Kamlet-Taft polarity parameters (hydrogen bond donating ability (α), hydrogen bond accepting ability (β) and dipolarity/polarizability polarity scale (π*)). Acceptable agreement was found between the maximum absorption band of dyes and solvent polarity parameters especially with π*. The effect of substituents of coupler and/or diazo component on the color of dyes was investigated. The effects of acid and base on the visible absorption maxima of the dyes are also reported.

  8. The effect of solvent on the kinetics of the oxidation of 3-methyl-2,6-diphenyl-piperidin-4-one by quinolinium fluorochromate in aqueous organic media

    Directory of Open Access Journals (Sweden)

    KUPPANAGOUNDER P. ELANGO

    2001-06-01

    Full Text Available The kinetics of the oxidation of 3-methyl-2,6-diphenyl-piperidin-4-one by quinolinium fluorochromate (QFC have been investigated in aqueous solutions of dimethyl sulphoxide, 1,4-dioxane, tert-butanol and acetone. The influence of the added co-solvent on the reactivity were analysed in the light of various simple and multiple regression equations, viz the Laidler-Eyring, Grunwald-Winstein, Swain and Kamlet-Taft equations. The obtained results showed that the solvation phenomenon plays a dominant role on the reactivity.

  9. Comparing and correlating solubility parameters governing the self-assembly of molecular gels using 1,3:2,4-dibenzylidene sorbitol as the gelator.

    Science.gov (United States)

    Lan, Yaqi; Corradini, Maria G; Liu, Xia; May, Tim E; Borondics, Ferenc; Weiss, Richard G; Rogers, Michael A

    2014-12-02

    Solvent properties play a central role in mediating the aggregation and self-assembly of molecular gelators and their growth into fibers. Numerous attempts have been made to correlate the solubility parameters of solvents and gelation abilities of molecular gelators, but a comprehensive comparison of the most important parameters has yet to appear. Here, the degree to which partition coefficients (log P), Henry's law constants (HLC), dipole moments, static relative permittivities (ε(r)), solvatochromic E(T)(30) parameters, Kamlet-Taft parameters (β, α, and π), Catalan's solvatochromic parameters (SPP, SB, and SA), Hildebrand solubility parameters (δ(i)), and Hansen solubility parameters (δ(p), δ(d), δ(h)) and the associated Hansen distance (R(ij)) of 62 solvents (covering a wide range of properties) can be correlated with the self-assembly and gelation of 1,3:2,4-dibenzylidene sorbitol (DBS) gelation, a classic molecular gelator, is assessed systematically. The approach presented describes the basis for each of the parameters and how it can be applied. As such, it is an instructional blueprint for how to assess the appropriate type of solvent parameter for use with other molecular gelators as well as with molecules forming other types of self-assembled materials. The results also reveal several important insights into the factors favoring the gelation of solvents by DBS. The ability of a solvent to accept or donate a hydrogen bond is much more important than solvent polarity in determining whether mixtures with DBS become solutions, clear gels, or opaque gels. Thermodynamically derived parameters could not be correlated to the physical properties of the molecular gels unless they were dissected into their individual HSPs. The DBS solvent phases tend to cluster in regions of Hansen space and are highly influenced by the hydrogen-bonding HSP, δ(h). It is also found that the fate of this molecular gelator, unlike that of polymers, is influenced not only by

  10. Negative solvatochromism of a series of pyridinium phenolate betaine dyes with increasing steric hindrance

    Science.gov (United States)

    Jacques, Patrice; Graff, Bernadette; Diemer, Vincent; Ay, Emel; Chaumeil, Hélène; Carré, Christiane; Malval, Jean-Pierre

    2012-04-01

    The negative solvatochromism of a series of pyridinium phenolates betaine dyes is investigated using three approaches: (a) empirical, based on the empirical solvent polarity parameter ET(30); (b) semi-empirical, based on the π∗, α, β set of parameters used in Kamlet-Taft's Solvatochromic Comparison Method (SCM); and (c) physical, by means of the Onsager reaction-field model of solvents. Comparison of the obtained correlations underscored the roles of both the two tert-butyl groups ortho to the oxygen atom and the interplanar angle between the phenyl rings on the very blue shifts observed as the polarity increases.

  11. Substituent and Solvent Effects on the Absorption Spectra of Cation-π Complexes of Benzene and Borazine: A Theoretical Study.

    Science.gov (United States)

    Sarmah, Nabajit; Bhattacharyya, Pradip Kr; Bania, Kusum K

    2014-05-14

    Time-dependent density functional theory (TDDFT) has been used to predict the absorption spectra of cation-π complexes of benzene and borazine. Both polarized continuum model (PCM) and discrete solvation model (DSM) and a combined effect of PCM and DSM on the absorption spectra have been elucidated. With decrease in size of the cation, the π → π* transitions of benzene and borazine are found to undergo blue and red shift, respectively. A number of different substituents (both electron-withdrawing and electron-donating) and a range of solvents (nonpolar to polar) have been considered to understand the effect of substituent and solvents on the absorption spectra of the cation-π complexes of benzene and borazine. Red shift in the absorption spectra of benzene cation-π complexes are observed with both electron-donating groups (EDGs) and electron-withdrawing groups (EWGs). The same trend has not been observed in the case of substituted borazine cation-π complexes. The wavelength of the electronic transitions corresponding to cation-π complexes correlates well with the Hammet constants (σp and σm). This correlation indicates that the shifting of spectral lines of the cation-π complexes on substitution is due to both resonance and inductive effect. On incorporation of solvent phases, significant red or blue shifting in the absorption spectra of the complexes has been observed. Kamlet-Taft multiparametric equation has been used to explain the effect of solvent on the absorption spectra of complexes. Polarity and polarizability are observed to play an important role in the solvatochromism of the cation-π complexes.

  12. Measurement of multicomponent solubility parameters for graphene facilitates solvent discovery.

    Science.gov (United States)

    Hernandez, Yenny; Lotya, Mustafa; Rickard, David; Bergin, Shane D; Coleman, Jonathan N

    2010-03-02

    We have measured the dispersibility of graphene in 40 solvents, with 28 of them previously unreported. We have shown that good solvents for graphene are characterized by a Hildebrand solubility parameter of delta(T) approximately 23 MPa(1/2) and Hansen solubility parameters of delta(D) approximately 18 MPa(1/2), delta(P) approximately 9.3 MPa(1/2), and delta(H) approximately 7.7 MPa(1/2). The dispersibility is smaller for solvents with Hansen parameters further from these values. We have used transmission electron microscopy (TEM) analysis to show that the graphene is well exfoliated in all cases. Even in relatively poor solvents, >63% of observed flakes have <5 layers.

  13. Solvatochromic behavior of the electronic absorption spectra of gallic acid and some of its azo derivatives

    Science.gov (United States)

    Masoud, Mamdouh S.; Hagagg, Sawsan S.; Ali, Alaa E.; Nasr, Nessma M.

    The electronic absorption spectra of gallic acid and its azo derivatives have been studied in various solvents of different polarities. Multiple regression techniques were applied to calculate the regression and correlation coefficients based on an equation that relates the wavenumbers of the absorption band maxima (υmax-) to the solvent parameters; refractive index (n), dielectric constant (D), empirical Kamlet-Taft solvent parameters, π*(dipolarity/polarizability), α (solvent hydrogen-bond donor acidity) and β (solvent hydrogen-bond acceptor basicity). The fitting coefficient obtained from this analysis allows estimating the contribution of each type of interactions relative to total spectral shifts in solution. The dependence of υmax- on the solvent parameters indicates that the obtained bands are affected by specific and non-specific solute-solvent interactions.

  14. Electronic Spectrum of different Bis-Schiff bases of Isatin and its Solvatochromism

    Directory of Open Access Journals (Sweden)

    *M. A. K. Tanoli

    2014-09-01

    Full Text Available The influence of a series of organic solvents on the UV spectra on some selected bis-Schiff base derivatives has been studied in a number of organic solvents with diverse polarities. As a part of our efforts to interpret the effects of solvent polarity and hydrogen bonding on the absorption spectra of previously synthesized bis-Schiff base derivatives, the study design was based on the linear solvation energy relationship (LSER concept using Kamlet-Taft solvatochromic parameters: π*, α and β. Correlation of spectroscopic data was carried out by means of multiple linear regression techniques. The fitting coefficient obtained from this analysis allows estimating the contribution of each type of interactions relative to total spectral shifts in solution. The dependence of (max on the solvent parameters indicated that the obtained bands were affected by specific and non-specific solute-solvent interactions.

  15. Fluorescence characteristics of aryl boronic acid derivate (PBA)

    Science.gov (United States)

    Patil, S. S.; Muddapur, G. V.; Patil, N. R.; Melavanki, R. M.; Kusanur, R. A.

    2015-03-01

    The absorption and fluorescence spectra of newly synthesized aryl boronic acid derivative namely Phenyl boronic acid (PBA) have been recorded in various solvents of different polarities. The ground state dipole moment of PBA was obtained from quantum chemical calculations. Solvatochromic correlations were used to estimate the ground state (μg) and excited state (μe) dipole moments. The excited state dipole moments are observed to be greater than the ground state dipole moments. Further, the ground and excited state dipole moments are not parallel but subtend by an angle of 70°. The changes in dipole moment (Δμ) were calculated both from solvatochromic shift method and microscopic solvent polarity parameter (ETN), and the values are compared. Solvent effects on the absorption and fluorescence spectra were quantified using Reichardt's and bulk solvent polarity parameters were complemented by the results of the Kamlet-Taft treatment.

  16. Averaged Solvent Embedding Potential Parameters for Multiscale Modeling of Molecular Properties.

    Science.gov (United States)

    Beerepoot, Maarten T P; Steindal, Arnfinn Hykkerud; List, Nanna Holmgaard; Kongsted, Jacob; Olsen, Jógvan Magnus Haugaard

    2016-04-12

    We derive and validate averaged solvent parameters for embedding potentials to be used in polarizable embedding quantum mechanics/molecular mechanics (QM/MM) molecular property calculations of solutes in organic solvents. The parameters are solvent-specific atom-centered partial charges and isotropic polarizabilities averaged over a large number of geometries of solvent molecules. The use of averaged parameters reduces the computational cost to obtain the embedding potential, which can otherwise be a rate-limiting step in calculations involving large environments. The parameters are evaluated by analyzing the quality of the resulting molecular electrostatic potentials with respect to full QM potentials. We show that a combination of geometry-specific parameters for solvent molecules close to the QM region and averaged parameters for solvent molecules further away allows for efficient polarizable embedding multiscale modeling without compromising the accuracy. The results are promising for the development of general embedding parameters for biomolecules, where the reduction in computational cost can be considerable.

  17. Solvent

    OpenAIRE

    Hamida Y. Mostafa; Ebaa A. El-Shamy; Amal S. Farag; Nadia G. Kandile

    2013-01-01

    Neat ethylacetoacetate (EAA) and its mixtures with a co-solvent and an anti-solvent have been studied for refining of heavy wax distillate fraction to produce substantially non-carcinogenic base oil. The co-solvent and anti-solvent used are dipropylene glycol (DPG) and ethylene glycol (EG) respectively. The solubility characteristics of the main solvent and its mixed solvent systems were studied. Selection of the optimum solvent mixture and extraction variables has been studied. The effect of...

  18. Metal Complexes as Color Indicators for Solvent Parameters.

    Science.gov (United States)

    Soukup, Rudolf W.; Schmid, Roland

    1985-01-01

    Although indicators are omnipresent tools in aqueous chemistry, they have not been used extensively to assign solvent properties in nonaqueous systems. Therefore, recent research into a system of metal complexes that can be used to assign donor and acceptor numbers to nonaqueous solvents is summarized. Pertinent experiments are also described. (JN)

  19. Averaged Solvent Embedding Potential Parameters for Multiscale Modeling of Molecular Properties

    DEFF Research Database (Denmark)

    Beerepoot, Maarten; Steindal, Arnfinn Hykkerud; List, Nanna Holmgaard

    2016-01-01

    We derive and validate averaged solvent parameters for embedding potentials to be used in polarizable embedding quantum mechanics/molecular mechanics (QM/MM) molecular property calculations of solutes in organic solvents. The parameters are solvent-specific atom-centered partial charges and isotr......We derive and validate averaged solvent parameters for embedding potentials to be used in polarizable embedding quantum mechanics/molecular mechanics (QM/MM) molecular property calculations of solutes in organic solvents. The parameters are solvent-specific atom-centered partial charges...... embedding multiscale modeling without compromising the accuracy. The results are promising for the development of general embedding parameters for biomolecules, where the reduction in computational cost can be considerable....

  20. Selecting water-alcohol mixed solvent for synthesis of polydopamine nano-spheres using solubility parameter

    OpenAIRE

    Jiang, Xiaoli; Wang, Yinling; Li, Maoguo

    2014-01-01

    The solvent plays an important role in a given chemical reaction. Since most reaction in nature occur in the mixed-solvent systems, a comprehensive principle for solvent optimization was required. By calculating the Hansen solubility parameters (HSP) distance Ra , we designed a model experiment to explore the influence of mixed solvents on the chemical synthesis. The synthesis of polydopamine (PDA) in the water-alcohol system was chosen as model. As predicted, the well-dispersed PDA spheres w...

  1. Multicomponent solubility parameters for single-walled carbon nanotube-solvent mixtures.

    Science.gov (United States)

    Bergin, Shane D; Sun, Zhenyu; Rickard, David; Streich, Philip V; Hamilton, James P; Coleman, Jonathan N

    2009-08-25

    We have measured the dispersibility of single-walled carbon nanotubes in a range of solvents, observing values as high as 3.5 mg/mL. By plotting the nanotube dispersibility as a function of the Hansen solubility parameters of the solvents, we have confirmed that successful solvents occupy a well-defined range of Hansen parameter space. The level of dispersibility is more sensitive to the dispersive Hansen parameter than the polar or H-bonding Hansen parameter. We estimate the dispersion, polar, and hydrogen bonding Hansen parameter for the nanotubes to be = 17.8 MPa(1/2), = 7.5 MPa(1/2), and = 7.6 MPa(1/2). We find that the nanotube dispersibility in good solvents decays smoothly with the distance in Hansen space from solvent to nanotube solubility parameters. Finally, we propose that neither Hildebrand nor Hansen solubility parameters are fundamental quantities when it comes to nanotube-solvent interactions. We show that the previously calculated dependence of nanotube Hildebrand parameter on nanotube diameter can be reproduced by deriving a simple expression based on the nanotube surface energy. We show that solubility parameters based on surface energy give equivalent results to Hansen solubility parameters. However, we note that, contrary to solubility theory, a number of nonsolvents for nanotubes have both Hansen and surface energy solubility parameters similar to those calculated for nanotubes. The nature of the distinction between solvents and nonsolvents remains to be fully understood.

  2. Partial solubility parameters and solvatochromic parameters for predicting the solubility of single and multiple drugs in individual solvents.

    Science.gov (United States)

    Bustamante, P; Martin, A; Gonzalez-Guisandez, M A

    1993-06-01

    A modification of the extended Hansen method is used for estimating the solubility of sulfadiazine and other organic drug molecules in a number of individual solvents ranging from nonpolar to highly polar. The equations obtained for each drug involve the partial solubility parameters of the solvents and allow the prediction of solubility of these drugs in a new solvent. Furthermore, a number of drugs (e.g., sulfadiazine, sulfamethoxypyridazine, naphthalene, and some benzoic acid derivatives) are combined in a single expression including the ideal solubility of the drugs and the partial solubility parameters of the solvents. The equation fits the solubilities of these drugs in a wide variety of solvents and may be used to predict the solubility of other sulfonamides and benzoic acid derivatives in semipolar and highly polar solvents. The solvatochromic parameter approach is also used in models for predicting the solubility of single drugs in individual solvents. It was tested with multiple solutes as was the partial solubility parameter approach. However, the latter approach is superior; the parameters of the solubility parameter method are all statistically significant for drugs tested individually or together in a single equation, a condition that is not obtained with the solvatochromic model.

  3. Molybdenum 1,4-diazabuta-1,3-diene tricarbonyl solvento complexes revisited: from solvatochromism to attractive ligand-ligand interaction.

    Science.gov (United States)

    Oelkers, Benjamin; Venker, Alexander; Sundermeyer, Jörg

    2012-04-16

    Various complexes of the types [Mo(DAD)(CO)(3)L] (L = CO, MeCN, MeOH, THF, DMSO, DMF, Me(2)CO, EtOAc, THT, Im(H), Im(1), tBuNC, nBu(3)P), (ER(4))[Mo(DAD)(CO)(3)X] (ER(4) = NEt(4)(+); X(-) = Cl(-), Br(-), I(-), NCS(-), CN(-) and ER(4)(+) = PPh(4)(+); X(-) = N(3)(-)), and (ER(4))[{Mo(DAD)(CO)(3)}(2)(μ-X)] (ER(4)(+) = NEt(4)(+); X(-) = CN(-), OAc(-) and ER(4)(+) = PPh(4)(+); X(-) = N(3)(-); DAD = N,N'-bis(2,6-dimethylphenyl)butane-2,3-diimine) were prepared by ligand exchange from cycloheptatriene molybdenum tricarbonyl. A total of 19 crystal structures were determined, including unprecedented structural characterization of molybdenum(0) coordination by dimethyl sulfoxide (DMSO), methanol, ethyl acetate (EtOAc), acetone, and N,N-dimethylformamide (DMF). Correlation of (13)C NMR shifts with the complex geometry suggests a direct ligand-ligand interaction between DAD and O-bonded coligands with C═O and S═O double bonds, such as EtOAc, Me(2)CO, DMF, and DMSO. Unexpectedly, the solvatochromic properties of these tricarbonyl complexes [Mo(DAD)(CO)(3)L] are unfavorable for the determination of Kamlet-Taft parameters of the corresponding solvent L. Contrastingly, the UV/vis absorption of [Mo(DAD)(CO)(4)] is strongly correlated with the Kamlet-Taft parameter π*, which is shown for 22 solvents, including seven room temperature ionic liquids.

  4. Selecting water-alcohol mixed solvent for synthesis of polydopamine nano-spheres using solubility parameter

    Science.gov (United States)

    Jiang, Xiaoli; Wang, Yinling; Li, Maoguo

    2014-08-01

    The solvent plays an important role in a given chemical reaction. Since most reaction in nature occur in the mixed-solvent systems, a comprehensive principle for solvent optimization was required. By calculating the Hansen solubility parameters (HSP) distance Ra, we designed a model experiment to explore the influence of mixed solvents on the chemical synthesis. The synthesis of polydopamine (PDA) in the water-alcohol system was chosen as model. As predicted, the well-dispersed PDA spheres were obtained in selected solvents with smaller Ra values: methanol/water, ethanol/water and 2-propanol/water. In addition, the mixed solvent with smaller Ra values gave a higher conversion of dopamine. The strategy for mixed solvent selection is might be useful to choose optimal reaction media for efficient chemical synthesis.

  5. Selecting water-alcohol mixed solvent for synthesis of polydopamine nano-spheres using solubility parameter

    Science.gov (United States)

    Jiang, Xiaoli; Wang, Yinling; Li, Maoguo

    2014-01-01

    The solvent plays an important role in a given chemical reaction. Since most reaction in nature occur in the mixed-solvent systems, a comprehensive principle for solvent optimization was required. By calculating the Hansen solubility parameters (HSP) distance Ra, we designed a model experiment to explore the influence of mixed solvents on the chemical synthesis. The synthesis of polydopamine (PDA) in the water-alcohol system was chosen as model. As predicted, the well-dispersed PDA spheres were obtained in selected solvents with smaller Ra values: methanol/water, ethanol/water and 2-propanol/water. In addition, the mixed solvent with smaller Ravalues gave a higher conversion of dopamine. The strategy for mixed solvent selection is might be useful to choose optimal reaction media for efficient chemical synthesis. PMID:25317902

  6. Mathematical modelling of simultaneous solvent evaporation and chemical curing in thermoset coatings: A parameter study

    DEFF Research Database (Denmark)

    Kiil, Søren

    2011-01-01

    A mathematical model, describing the curing behaviour of a two-component, solvent-based, thermoset coating, is used to conduct a parameter study. The model includes curing reactions, solvent intra-film diffusion and evaporation, film gelation, vitrification, and crosslinking. A case study with a ...

  7. Predicting the solubility of sulfamethoxypyridazine in individual solvents. II: Relationship between solute-solvent interaction terms and partial solubility parameters.

    Science.gov (United States)

    Martin, A; Bustamante, P; Escalera, B; Sellés, E

    1989-08-01

    In the first paper in the series, an expanded system of parameters was devised to account for orientation and induction effects, and the term Wh was introduced to replace delta 1h delta 2h of the extended Hansen solubility approach. In the present report, a new term, Kh = Wh/delta 1h delta 2h is observed to take on values larger or smaller than unity depending on whether the hydrogen bonded solute-solvent interaction is larger or smaller than predicted by the term delta 1h delta 2h. The acidic delta a and basic delta b solubility parameters are used to represent two parameters, sigma and tau, suggested by Small in his study of proton donor-acceptor properties. The Small equation, including a heat of mixing term for hydrogen bonded species, is shown to be capable of semiquantitative evaluation. A partial molar heat delta H2h of hydrogen bonding is calculated using delta h and Wh terms; delta H2h is found to be correlated with the logarithm of the residual activity coefficient, In alpha R, a term representing strong solute-solvent interaction. The terms Wh, delta H2h, and In alpha 2R may be used to test the deviation from the geometric mean assumed in regular solution theory, and to replace the hydrogen bonding terms of the extended Hansen three-parameter model. The solubility of sulfamethoxypyridazine in 30 solvents is used to test the semiempirical solubility equations. The results are interpreted in terms of partial solubility parameters and the proton donor-acceptor properties of the solvents.

  8. Determining an Efficient Solvent Extraction Parameters for Re-Refining of Waste Lubricating Oils

    Directory of Open Access Journals (Sweden)

    Hassan Ali Durrani

    2012-04-01

    Full Text Available Re-refining of vehicle waste lubricating oil by solvent extraction is one of the efficient and cheapest methods. Three extracting solvents MEK (Methyl-Ethyl-Ketone, 1-butanol, 2-propanol were determined experimentally for their performance based on the parameters i.e. solvent type, solvent oil ratio and extraction temperature. From the experimental results it was observed the MEK performance was highest based on the lowest oil percent losses and highest sludge removal. Further, when temperature of extraction increased the oil losses percent also decreased. This is due to the solvent ability that dissolves the base oil in waste lubricating oil and determines the best SOR (Solvent Oil Ratio and extraction temperatures.

  9. Determination of poly(epsilon-caprolactone) solubility parameters: application to solvent substitution in a microencapsulation process.

    Science.gov (United States)

    Bordes, C; Fréville, V; Ruffin, E; Marote, P; Gauvrit, J Y; Briançon, S; Lantéri, P

    2010-01-04

    The evolution of regulation on chemical substances (i.e. REACH regulation) calls for the progressive substitution of toxic chemicals in formulations when suitable alternatives have been identified. In this context, the method of Hansen solubility parameters was applied to identify an alternative solvent less toxic than methylene chloride used in a microencapsulation process. During the process based on a multiple emulsion (W/O/W) with solvent evaporation/extraction method, the solvent has to dissolve a polymer, poly(epsilon-caprolactone) (PCL), which forms a polymeric matrix encapsulating or entrapping a therapeutic protein as the solvent is extracted. Therefore the three partial solubility parameters of PCL have been determined by a group contribution method, swelling experiments and turbidimetric titration. The results obtained allowed us to find a solvent, anisole, able to solubilize PCL and to form a multiple emulsion with aqueous solutions. A feasibility test was conducted under standard operating conditions and allowed the production of PCL microspheres.

  10. How to design a good photoresist solvent package using solubility parameters and high-throughput research

    Science.gov (United States)

    Tate, Michael P.; Cutler, Charlotte; Sakillaris, Mike; Kaufman, Michael; Estelle, Thomas; Mohler, Carol; Tucker, Chris; Thackeray, Jim

    2014-03-01

    Understanding fundamental properties of photoresists and how interactions between photoresist components affect performance targets are crucial to the continued success of photoresists. More specifically, polymer solubility is critical to the overall performance capability of the photoresist formulation. While several theories describe polymer solvent solubility, the most common industrially applied method is Hansen's solubility parameters. Hansen's method, based on regular solution theory, describes a solute's ability to dissolve in a solvent or solvent blend using four physical properties determined experimentally through regression of solubility data in many known solvents. The four physical parameters are dispersion, polarity, hydrogen bonding, and radius of interaction. Using these parameters a relative cohesive energy difference (RED), which describes a polymer's likelihood to dissolve in a given solvent blend, may be calculated. Leveraging a high throughput workflow to prepare and analyze the thousands of samples necessary to calculate the Hansen's solubility parameters from many different methacrylate-based polymers, we compare the physical descriptors to reveal a large range of polarities and hydrogen bonding. Further, we find that Hansen's model correctly predicts the soluble/insoluble state of 3-component solvent blends where the dispersion, polar, hydrogen-bonding, and radius of interaction values were determined through regression of experimental values. These modeling capabilities have allowed for optimization of the photoresist solubility from initial blending through application providing valuable insights into the nature of photoresist.

  11. The expanded Hansen approach to solubility parameters. Paracetamol and citric acid in individual solvents.

    Science.gov (United States)

    Barra, J; Lescure, F; Doelker, E; Bustamante, P

    1997-07-01

    In this study two solubility-parameter models have been compared using as dependent variables the logarithm of the mole fraction solubility, lnX2e, and ln(alpha)/U (originally used in the extended Hansen method), where alpha is the activity coefficient and U is a function of the molar volume of the solute and the volume fraction of the solvent. The results show for the first time the proton-donor and -acceptor hydrogen-bonding capacities of paracetamol, as measured by the acidic and basic partial-solubility parameters. The influence of solvents on the differential scanning calorimetry (DSC) pattern of the solid phases was also studied in relation to the solubility models tested. Citric acid was chosen as a test substance because of its high acidity and its proton donor capacity to form hydrogen bonds with basic solvents. The partial acidic and basic solubility parameters obtained from multiple regression were consistent with this property, validating the model chosen. The results show that the more direct lnX2e variable was more suitable for fitting both models, and the four-parameter model seemed better for describing the interactions between solvent and solute.

  12. Determination of partial solubility parameters of five benzodiazepines in individual solvents.

    Science.gov (United States)

    Verheyen, S; Augustijns, P; Kinget, R; Van den Mooter, G

    2001-10-09

    Three and four component partial solubility parameters for diazepam, lorazepam, oxazepam, prazepam and temazepam were determined using the extended and expanded Hansen regression models. A comparison was made also with solubility parameters calculated by the group contribution method proposed by Van Krevelen. Although a limited number of solvents was used, the results from the present study indicate that the partial solubility parameters obtained from the experimental regression models clearly reflect the structural differences in these five structurally related molecules. High R(2)-values were observed in the regression models (0.932 parameter did not improve the R(2)- and F-values in any of the regression models used.

  13. Morphologies in Solvent-Annealed Clotrimazole Thin Films Explained by Hansen-Solubility Parameters.

    Science.gov (United States)

    Ehmann, Heike M A; Zimmer, Andreas; Roblegg, Eva; Werzer, Oliver

    2014-03-05

    The induction of different crystal morphologies is of crucial importance for many applications. In this work, the preparation of various crystal morphologies within clotrimazole films on glass substrates is demonstrated. Amorphous clotrimazole thin films were transformed via vapor annealing into crystalline structures; highly monodisperse/multidisperse crystallites, spherulite, or dendritic structures were obtained as the solvent was exchanged. X-ray diffraction experiments reveal that the same polymorph is present for all samples but with varying texture. The achieved morphologies are explained in terms of Hansen-solubility parameters and vapor pressures; thus, the different morphologies and crystal orientations can be explained by solvent-solid interaction strengths within the thin film samples.

  14. Predicting the Activity Coefficients of Free-Solvent for Concentrated Globular Protein Solutions Using Independently Determined Physical Parameters

    OpenAIRE

    McBride, Devin W; Rodgers, Victor G. J.

    2013-01-01

    The activity coefficient is largely considered an empirical parameter that was traditionally introduced to correct the non-ideality observed in thermodynamic systems such as osmotic pressure. Here, the activity coefficient of free-solvent is related to physically realistic parameters and a mathematical expression is developed to directly predict the activity coefficients of free-solvent, for aqueous protein solutions up to near-saturation concentrations. The model is based on the free-solvent...

  15. Investigation of the effect of organic solvents on kinetic parameters in metal catalyzed reactions

    Directory of Open Access Journals (Sweden)

    GORDANA A. MILOVANOVIC

    2000-03-01

    Full Text Available The effects of acetone and acetonitrile on the kinetic parameters of azorubin S oxidation by hydrogen peroxide catalyzed by manganese(II, pyrocatechol violet oxidation by hydrogen peroxide catalyzed by copper(II, and carminic acid oxidation by hydrogen peroxide catalyzed by copper(II and activated by bifenox, were examined. It was established that the examined solvents exhibit various effects on the kinetic parameters of the above said reactions. In a11 instances a change in the solvent concentration effects both the anthalpy and the entropy contributions to the free activation energy during the transition of the system into the active state, as well as the constant of the active complex formed at this point.

  16. Effect of Solvents on the Ultrasonic Velocity and Acoustic Parameters of Polyvinylidene Fluoride Solutions

    Directory of Open Access Journals (Sweden)

    S. S. Kulkarni

    2016-01-01

    Full Text Available Ultrasonic studies provide a wealth of information in understanding the molecular behavior and intermolecular interaction of polymer solvent mixtures. Attempts were made to measure ultrasonic velocity, density, and viscosity for the mixture of polyvinylidene fluoride (PVDF in acetone and dimethylformamide (DMF of various stoichiometric ratios at 300 K using crystal controlled ultrasonic interferometer (Mittal make, pyknometer (specific gravity bottle, and Ostwald viscometer, respectively. The acoustic parameters adiabatic compressibility (β, intermolecular free path length (Lf, acoustic impedance (Z, relative association (RA, ultrasonic attenuation (α/f2, and relaxation time (τ have been estimated using experimental data with well-known techniques. The variation of these acoustic parameters is explained in terms of solute-solvent molecular interaction in a polymer solution.

  17. THERMODYNAMIC PARAMETERS OF SOLUTIONS OF SILDENAFIL CITRATE IN SOME ORGANIC SOLVENTS AT DIFFERENT TEMPERATURES

    OpenAIRE

    S. BALUJA; K. Bhesaniya

    2015-01-01

    The solubility of Sildenafil citrate in some organic solvents; hexane, toluene,1-butanol and 1,2 dichloroethane has been determined using gravimetric method over different temperature range (298.15 K to 328.15 K) at one atmospheric pressure. The modified Apelblat and Buchowski-Ksiazczak λh equations were used to correlate the experimental solubility data. Further, various thermodynamic parameters have been evaluated from these solubility data.

  18. THERMODYNAMIC PARAMETERS OF SOLUTIONS OF SILDENAFIL CITRATE IN SOME ORGANIC SOLVENTS AT DIFFERENT TEMPERATURES

    Directory of Open Access Journals (Sweden)

    S. Baluja

    2015-07-01

    Full Text Available The solubility of Sildenafil citrate in some organic solvents; hexane, toluene,1-butanol and 1,2 dichloroethane has been determined using gravimetric method over different temperature range (298.15 K to 328.15 K at one atmospheric pressure. The modified Apelblat and Buchowski-Ksiazczak λh equations were used to correlate the experimental solubility data. Further, various thermodynamic parameters have been evaluated from these solubility data.

  19. THERMODYNAMIC PARAMETERS OF SOLUTIONS OF SILDENAFIL CITRATE IN SOME ORGANIC SOLVENTS AT DIFFERENT TEMPERATURES

    Directory of Open Access Journals (Sweden)

    S. Baluja

    2014-06-01

    Full Text Available The solubility of Sildenafil citrate in some organic solvents; hexane, toluene,1-butanol and 1,2 dichloroethane has been determined using gravimetric method over different temperature range (298.15 K to 328.15 K at one atmospheric pressure. The modified Apelblat and Buchowski-Ksiazczak λh equations were used to correlate the experimental solubility data. Further, various thermodynamic parameters have been evaluated from these solubility data.

  20. Solvatochromism and preferential solvation in mixtures of Methanol with Ethanol, 1-Propanol and 1-Butanol

    Directory of Open Access Journals (Sweden)

    Masoumeh Sayadian

    2014-12-01

    Full Text Available The spectral shift of 4-nitroaniline was determined in pure methanol, ethanol, 1-propanol and 1-butanol and binary mixtures of methanol with other 1-alkanols at 25 ⁰C by UV-vis spectroscopy. The effect of specific and non-specific solute-solvent interactions on the spectral shift was investigated by using the linear solvation energy relationship concept. A multiple linear regression analysis was used to correlate the spectral shift with microscopic Kamlet-Taft parameters (a, b and p* in pure solvents. Results indicate that the spectral shift is highly related with the specific solute-solvent interactions. In binary mixtures, a nonideal behavior of spectral shift was observed respective to the analytical mole fraction of alcohols; indicating preferential solvation. The spectral shifts were fitted to a known preferential solvation model named solvent exchange model to calculate the preferential solvation parameters. The preference of solute to be solvated by one of the solvating species relative to others was explained in terms of solvent-solvent and solute-solvent interactions.

  1. Minimal parameter implicit solvent model for ab initio electronic structure calculations

    CERN Document Server

    Dziedzic, Jacek; Skylaris, Chris-Kriton; Mostofi, Arash A; Payne, Mike C

    2011-01-01

    We present an implicit solvent model for ab initio electronic structure calculations which is fully self-consistent and is based on direct solution of the nonhomogeneous Poisson equation. The solute cavity is naturally defined in terms of an isosurface of the electronic density according to the formula of Fattebert and Gygi (J. Comp. Chem. 23, 6 (2002)). While this model depends on only two parameters, we demonstrate that by using appropriate boundary conditions and dispersion-repulsion contributions, solvation energies obtained for an extensive test set including neutral and charged molecules show dramatic improvement compared to existing models. Our approach is implemented in, but not restricted to, a linear-scaling density functional theory (DFT) framework, opening the path for self-consistent implicit solvent DFT calculations on systems of unprecedented size, which we demonstrate with calculations on a 2615-atom protein-ligand complex.

  2. Thermal and solvent effects on NMR spectroscopy parameters of a prototypical Chagas disease drug

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2011-07-01

    understood on the basis of semiclassical physics, J-coupling is a purely quantum- mechanical phenomenon. The present results provide evidence that hyperconjugative effects in solute molecules are not due to changes in geometric parameters upon solvation, but arise from the direct response of the electronic wave function to the presence of the solvent, which can be represented by discrete molecules and/or the dielectric bulk. We believe that our findings may be helpful to rationalize the relation between NMR parameters and the interactions in hydrogen-bonded complexes. Further applications along these lines are in progress. (author)

  3. Solvents effect on the absorption and fluorescence spectra of 7-diethylamino-3-thenoylcoumarin: evaluation and correlation between solvatochromism and solvent polarity parameters.

    Science.gov (United States)

    Basavaraja, Jana; Inamdar, S R; Suresh Kumar, H M

    2015-02-25

    Effect of solvents of varying polarities on absorption and fluorescence spectra and dipole moment of laser dye: 7-diethylamino-3-thenoylcoumarin (DETC) has been investigated. A small band shift is obtained in the absorption spectra compared to emission spectra. The spectral shifts were correlated with Catalan's parameters using linear solvation energy relationship. It reveals that non-specific interaction measured by solvent polarity has more influence on absorption and solvent dipolarity contribution is significant in case of fluorescence. A bathochromic shift observed in absorption and emission spectra with increasing solvent polarity, which implied that the transition involved is π→π(∗). The solvatochromic correlations were used to estimate the excited state dipole moment using experimentally determined ground state dipole moment. The observed single-state excited state dipole moment is found to be greater than the ground state.

  4. Predicting the activity coefficients of free-solvent for concentrated globular protein solutions using independently determined physical parameters.

    Directory of Open Access Journals (Sweden)

    Devin W McBride

    Full Text Available The activity coefficient is largely considered an empirical parameter that was traditionally introduced to correct the non-ideality observed in thermodynamic systems such as osmotic pressure. Here, the activity coefficient of free-solvent is related to physically realistic parameters and a mathematical expression is developed to directly predict the activity coefficients of free-solvent, for aqueous protein solutions up to near-saturation concentrations. The model is based on the free-solvent model, which has previously been shown to provide excellent prediction of the osmotic pressure of concentrated and crowded globular proteins in aqueous solutions up to near-saturation concentrations. Thus, this model uses only the independently determined, physically realizable quantities: mole fraction, solvent accessible surface area, and ion binding, in its prediction. Predictions are presented for the activity coefficients of free-solvent for near-saturated protein solutions containing either bovine serum albumin or hemoglobin. As a verification step, the predictability of the model for the activity coefficient of sucrose solutions was evaluated. The predicted activity coefficients of free-solvent are compared to the calculated activity coefficients of free-solvent based on osmotic pressure data. It is observed that the predicted activity coefficients are increasingly dependent on the solute-solvent parameters as the protein concentration increases to near-saturation concentrations.

  5. Predicting the activity coefficients of free-solvent for concentrated globular protein solutions using independently determined physical parameters.

    Science.gov (United States)

    McBride, Devin W; Rodgers, Victor G J

    2013-01-01

    The activity coefficient is largely considered an empirical parameter that was traditionally introduced to correct the non-ideality observed in thermodynamic systems such as osmotic pressure. Here, the activity coefficient of free-solvent is related to physically realistic parameters and a mathematical expression is developed to directly predict the activity coefficients of free-solvent, for aqueous protein solutions up to near-saturation concentrations. The model is based on the free-solvent model, which has previously been shown to provide excellent prediction of the osmotic pressure of concentrated and crowded globular proteins in aqueous solutions up to near-saturation concentrations. Thus, this model uses only the independently determined, physically realizable quantities: mole fraction, solvent accessible surface area, and ion binding, in its prediction. Predictions are presented for the activity coefficients of free-solvent for near-saturated protein solutions containing either bovine serum albumin or hemoglobin. As a verification step, the predictability of the model for the activity coefficient of sucrose solutions was evaluated. The predicted activity coefficients of free-solvent are compared to the calculated activity coefficients of free-solvent based on osmotic pressure data. It is observed that the predicted activity coefficients are increasingly dependent on the solute-solvent parameters as the protein concentration increases to near-saturation concentrations.

  6. Relationship between the spectral properties of solutions of borofluoride complex of alkylated dipyrromethene and the physicochemical parameters of solvents

    Science.gov (United States)

    Marfin, Yu. S.; Rumyantsev, E. V.; Fadeev, Ya. S.; Antina, E. V.

    2012-07-01

    Spectral and photophysical characteristics of borofluoride complex of alkylated dipyrromethene (Bodipy) are determined by means of absorption and fluorescence electron spectroscopy in various organic solvents. Dependences of the spectral and photophysical characteristics of Bodipy solutions vs. the physico-chemical parameters of solvents are obtained by linear regression analysis and the contribution from each parameter to the property under study is determined. It is established that the negative solvatochromic effect is intrinsic for Bodipy. It is concluded that specific interactions contribute substantially to the properties of the chromophore, which are determined by the electron donor properties of the solvent.

  7. Estimation of ground and excited state dipole moment of laser dyes C504T and C521T using solvatochromic shifts of absorption and fluorescence spectra.

    Science.gov (United States)

    Basavaraja, Jana; Kumar, H M Suresh; Inamdar, S R; Wari, M N

    2016-02-05

    The absorption and fluorescence spectra of laser dyes: coumarin 504T (C504T) and coumarin 521T (C521T) have been recorded at room temperature in a series of non-polar and polar solvents. The spectra of these dyes showed bathochromic shift with increasing in solvent polarity indicating the involvement of π→π⁎ transition. Kamlet-Taft and Catalan solvent parameters were used to analyze the effect of solvents on C504T and C521T molecules. The study reveals that both general solute-solvent interactions and specific interactions are operative in these two systems. The ground state dipole moment was estimated using Guggenheim's method and also by quantum mechanical calculations. The solvatochromic data were used to determine the excited state dipole moment (μ(e)). It is observed that dipole moment value of excited state (μ(e)) is higher than that of the ground state in both the laser dyes indicating that these dyes are more polar in nature in the excited state than in the ground state.

  8. An explanation of dispersion states of single-walled carbon nanotubes in solvents and aqueous surfactant solutions using solubility parameters.

    Science.gov (United States)

    Ham, Hyeong Taek; Choi, Yeong Suk; Chung, In Jae

    2005-06-01

    Dispersions of single-walled carbon nanotubes in various solvents and aqueous surfactant emulsions were investigated to correlate the degree of dispersion state with Hansen solubility parameters (deltat2=deltad2+deltap2+deltah2). It was found that the nanotubes were dispersed or suspended very well in the solvents with certain dispersive component (deltad) values. They were precipitated in the solvents with high polar component (deltap) values or hydrogen-bonding component (deltah) values. The solvents in the dispersed group occupied a certain region in a 3-dimensional space of three components. The surfactants with a lipophilic group equal to and longer than decyl, containing 9 methylene groups and 1 methyl group, contributed to the dispersion of nanotubes in water. The surfactants in the dispersed group had a lower limit in the dispersive component (deltad) of the Hansen parameter.

  9. Quinazolinone derivative: Model compound for determination of dipole moment, solvatochromism and metal ion sensing

    Science.gov (United States)

    Al-Sehemi, Abdullah G.; Pannipara, Mehboobali; Kalam, Abul

    2017-01-01

    A dihydroquinazolinone derivative 2-(2,4-Dimethoxy-phenyl)-2,3-dihydro-1H-quinazolin-4-one (1) was synthesized and characterized by 1H NMR, 13C NMR and FT-IR and its spectral, photophysical, intramolecular charge transfer characteristics were studied by absorption and emission spectroscopy. The compound exhibits significant changes in their photophysical properties depending on the solvent polarity. The observed bathochromic emission band and difference in Stokes shift on changing the polarity of the solvents clearly demonstrate the highly polar character of the excited state, which is also supported by the enhancement of dipole moment of the molecule upon photoexcitation. Solvatochromic shift methods based on Lippert-Mataga, Bakhshiev-Kawski and Reichardt's correlations were applied to calculate the ground, excited and change in dipole moments. The effect of solute-solvent interactions on compound 1 was studied using multi-parameter solvent polarity scales proposed by Kamlet-Taft and Catalan. The interactions of various metal ions on compound 1 were also studied using steady state fluorescence measurements. The emission profile reveals that it acts as on-off type fluorescent chemosensor for selective and sensitive detection of Hg2 + ions. Complexation stoichiometry and mechanism of quenching were determined from Benesi-Hildebrand and Stern-Volmer plot.

  10. Solvatochromism of isatin based Schiff bases: An LSER and LFER study

    Directory of Open Access Journals (Sweden)

    Brkić Dominik R.

    2016-01-01

    Full Text Available The derivatives of isatin have already been reported to show a variety of biological activities. However, there has been no report on solvatochromic effect of isatin derivatives so far, and that could be of interest to study and relate to their electronic structure, as a part of the characterisation of these compounds. Linear solvation energy relationships (LSER were used to analyze solvent influence on the UV absorption maxima shifts of investigated isatin derivatives, i.e. isatin based Schiff bases, by using Kamlet-Taft model. Linear free energy relationships (LFER were applied to the substituent-induced NMR chemical shifts (SCS using SSP (single substituent parameter. The obtained correlations together with theoretical calculations gave insight into the influence of the molecular conformation on the transmission of substituent effects, as well as on solute/solvent interactions. The molecular electrostatic potential (MEP surface map was plotted over the optimized geometry of the molecules in order to visualize electron density distribution and explain origin of solvent/solute interactions. [Projekat Ministarstva nauke Republike Srbije, br. 172013

  11. The influence of non-solvent addition on the independent and dependent parameters in roller electrospinning of polyurethane.

    Science.gov (United States)

    Cengiz-Callioglu, Funda; Jirsak, Oldrich; Dayik, Mehmet

    2013-07-01

    This paper discusses the effects of 1,1,2,2 tetrachlorethylen (TCE) non-solvent addition on the independent (electrical conductivity, dielectric constant, surface tension and the theological properties of the solution etc.) and dependent parameters (number of Taylor cones per square meter (NTC/m2), spinning performance for one Taylor cone (SP/TC), total spinning performance (SP), fiber properties such as diameter, diameter uniformity, non-fibrous area) in roller electrospinning of polyurethane (PU). The same process parameters (voltage, distance of the electrodes, humidity, etc.) were applied for all solutions during the spinning process. According to the results, the effect of TCE non-solvent concentration on the dielectric constant, surface tension, rheological properties of the solution and also spinning performance was important statistically. Beside these results, TCE non-solvent concentration effects quality of fiber and nano web structure. Generally high fiber density, low non-fibrous percentage and uniform nanofibers were obtained from fiber morphology analyses.

  12. Structure-retention and mobile phase-retention relationships for reversed-phase high-performance liquid chromatography of several hydroxythioxanthone derivatives in binary acetonitrile-water mixtures

    Energy Technology Data Exchange (ETDEWEB)

    Amiri, Ali Asghar; Hemmateenejad, Bahram; Safavi, Afsaneh; Sharghi, Hashem; Beni, Ali Reza Salimi [Department of Chemistry, Shiraz University, Shiraz (Iran, Islamic Republic of); Shamsipur, Mojtaba [Department of Chemistry, Razi University, Kermanshah (Iran, Islamic Republic of)], E-mail: mshamsipur@yahoo.com

    2007-12-12

    The reversed-phase high-performance liquid chromatographic (RP-HPLC) behavior of some newly synthesized hydroxythioxanthone derivatives using binary acetonitrile-water mixtures as mobile phase has been examined. First, the variation in the retention time of each molecule as a function of mobile phase properties was studied by Kamlet-Taft solvatochromic equations. Then, the influences of molecular structure of the hydroxythioxanthone derivatives on their retention time in various mobile phase mixtures were investigated by quantitative structure-property relationship (QSPR) analysis. Finally, a unified model containing both the molecular structure parameters and mobile phase properties was developed to describe the chromatographic behavior of the systems studied. Among the solvent properties, polarity/polarizability parameter ({pi}{sup *}) and hydrogen-bond basicity ({beta}), and among the solute properties, the most positive local charge (MPC), the sum of positive charges on hydrogen atoms contributing in hydrogen bonding (SPCH) and lipophilicity index (log P) were identified as controlling factors in the RP-HPLC behavior of hydroxythioxanthone derivatives in actonitrile-water binary solvents.

  13. Structure-retention and mobile phase-retention relationships for reversed-phase high-performance liquid chromatography of several hydroxythioxanthone derivatives in binary acetonitrile-water mixtures.

    Science.gov (United States)

    Amiri, Ali Asghar; Hemmateenejad, Bahram; Safavi, Afsaneh; Sharghi, Hashem; Beni, Ali Reza Salimi; Shamsipur, Mojtaba

    2007-12-12

    The reversed-phase high-performance liquid chromatographic (RP-HPLC) behavior of some newly synthesized hydroxythioxanthone derivatives using binary acetonitrile-water mixtures as mobile phase has been examined. First, the variation in the retention time of each molecule as a function of mobile phase properties was studied by Kamlet-Taft solvatochromic equations. Then, the influences of molecular structure of the hydroxythioxanthone derivatives on their retention time in various mobile phase mixtures were investigated by quantitative structure-property relationship (QSPR) analysis. Finally, a unified model containing both the molecular structure parameters and mobile phase properties was developed to describe the chromatographic behavior of the systems studied. Among the solvent properties, polarity/polarizability parameter (pi*) and hydrogen-bond basicity (beta), and among the solute properties, the most positive local charge (MPC), the sum of positive charges on hydrogen atoms contributing in hydrogen bonding (SPCH) and lipophilicity index (logP) were identified as controlling factors in the RP-HPLC behavior of hydroxythioxanthone derivatives in actonitrile-water binary solvents.

  14. Self-assembly of 2,3-dihydroxycholestane steroids into supramolecular organogels as a soft template for the in-situ generation of silicate nanomaterials.

    Science.gov (United States)

    Edelsztein, Valeria C; Mac Cormack, Andrea S; Ciarlantini, Matías; Di Chenna, Pablo H

    2013-01-01

    Supramolecular gels are an important and interesting class of soft materials that show great potential for many applications. Most of them have been discovered serendipitously, and understanding the supramolecular self-assembly that leads to the formation of the gel superstructure is the key to the directed design of new organogels. We report herein the organogelating property of four stereoisomers of the simple steroid 2,3-dihydroxycholestane. Only the isomer with the trans-diaxial hydroxy groups had the ability to gelate a broad variety of liquids and, thus, to be a super-organogelator for hydrocarbons. The scope of solvent gelation was analysed with regard to two solvent parameters, namely the Kamlet-Taft and the Hansen solubility parameters. The best correlation was observed with the Hansen approach that revealed the existence of two clear gelation zones. We propose a general model of self-assembly through multiple intermolecular hydrogen bonds between the 1,2-dihydroxy system, which is based on experimental data and computational simulations revealing the importance of the di-axial orientation of the hydroxy groups for the one-dimensional self-assembly. Under controlled conditions, the fibrillar superstructure of the organogel was successfully used as a template for the in-situ sol-gel polymerization of tetraethoxysilane and the further preparation of silica nanotubes. We propose that the driving forces for templating are hydrogen bonding and electrostatic interactions between the anionic silicate intermediate species and the self-assembled fibrillar network.

  15. New blue emissive conjugated small molecules with low lying HOMO energy levels for optoelectronic applications

    Science.gov (United States)

    Trupthi Devaiah, C.; Hemavathi, B.; Ahipa, T. N.

    2017-03-01

    Versatile conjugated small molecules bearing cyanopyridone core (CP1-5), composed of various donor/acceptor moieties at position - 4 and - 6 have been designed, developed and characterized. Their solvatochromic studies were conducted and analyzed using Lippert-Mataga, Kamlet-Taft and Catalan solvent scales and interesting results were obtained. The polarizability/dipolarity of the solvent greatly influenced the spectra. The electrochemical studies were carried out using cyclic voltammetry to calculate the HOMO-LUMO energy levels. The study revealed that the synthesized conjugated small molecules possess low lying HOMO energy levels which can be exploited for application in various fields of optoelectronics.

  16. Morphologies in Solvent-Annealed Clotrimazole Thin Films Explained by Hansen-Solubility Parameters

    OpenAIRE

    Ehmann, Heike M. A.; Zimmer, Andreas; Roblegg, Eva; Werzer, Oliver

    2014-01-01

    The induction of different crystal morphologies is of crucial importance for many applications. In this work, the preparation of various crystal morphologies within clotrimazole films on glass substrates is demonstrated. Amorphous clotrimazole thin films were transformed via vapor annealing into crystalline structures; highly monodisperse/multidisperse crystallites, spherulite, or dendritic structures were obtained as the solvent was exchanged. X-ray diffraction experiments reveal that the sa...

  17. Quantification of interaction and topological parameters of polyisoprene star polymers under good solvent conditions

    KAUST Repository

    Rai, Durgesh K.

    2016-05-05

    Mass fractal scaling, reflected in the mass fractal dimension df, is independently impacted by topology, reflected in the connectivity dimension c, and by tortuosity, reflected in the minimum dimension dmin. The mass fractal dimension is related to these other dimensions by df=cdmin. Branched fractal structures have a higher mass fractal dimension compared to linear structures due to a higher c, and extended structures have a lower dimension compared to convoluted self-avoiding and Gaussian walks due to a lower dmin. It is found, in this work, that macromolecules in thermodynamic equilibrium display a fixed mass fractal dimension df under good solvent conditions, regardless of chain topology. These equilibrium structures accommodate changes in chain topology such as branching c by a decrease in chain tortuosity dmin. Symmetric star polymers are used to understand the structure of complex macromolecular topologies. A recently published hybrid Unified scattering function accounts for interarm correlations in symmetric star polymers along with polymer-solvent interaction for chains of arbitrary scaling dimension. Dilute solutions of linear, three-arm and six-arm polyisoprene stars are studied under good solvent conditions in deuterated p-xylene. Reduced chain tortuosity can be viewed as steric straightening of the arms. Steric effects for star topologies are quantified, and it is found that steric straightening of arms is more significant for lower-molecular-weight arms. The observation of constant df is explained through a modification of Flory-Krigbaum theory for branched polymers.

  18. Quantification of interaction and topological parameters of polyisoprene star polymers under good solvent conditions

    Science.gov (United States)

    Rai, Durgesh K.; Beaucage, Gregory; Ratkanthwar, Kedar; Beaucage, Peter; Ramachandran, Ramnath; Hadjichristidis, Nikos

    2016-05-01

    Mass fractal scaling, reflected in the mass fractal dimension df, is independently impacted by topology, reflected in the connectivity dimension c , and by tortuosity, reflected in the minimum dimension dmin. The mass fractal dimension is related to these other dimensions by df=c dmin . Branched fractal structures have a higher mass fractal dimension compared to linear structures due to a higher c , and extended structures have a lower dimension compared to convoluted self-avoiding and Gaussian walks due to a lower dmin. It is found, in this work, that macromolecules in thermodynamic equilibrium display a fixed mass fractal dimension df under good solvent conditions, regardless of chain topology. These equilibrium structures accommodate changes in chain topology such as branching c by a decrease in chain tortuosity dmin. Symmetric star polymers are used to understand the structure of complex macromolecular topologies. A recently published hybrid Unified scattering function accounts for interarm correlations in symmetric star polymers along with polymer-solvent interaction for chains of arbitrary scaling dimension. Dilute solutions of linear, three-arm and six-arm polyisoprene stars are studied under good solvent conditions in deuterated p -xylene. Reduced chain tortuosity can be viewed as steric straightening of the arms. Steric effects for star topologies are quantified, and it is found that steric straightening of arms is more significant for lower-molecular-weight arms. The observation of constant df is explained through a modification of Flory-Krigbaum theory for branched polymers.

  19. Empirical parameters for solvent acidity, basicity, dipolarity, and polarizability of the ionic liquids [BMIM][BF4] and [BMIM][PF6].

    Science.gov (United States)

    del Valle, J C; García Blanco, F; Catalán, J

    2015-04-02

    The empirical solvent scales for polarizability (SP), dipolarity (SdP), acidity (SA), and basicity (SB) have been successfully used to interpret the solvatochromism of compounds dissolved in organic solvents and their solvent mixtures. Providing that the published solvatochromic parameters for the ionic liquids 1-(1-butyl)-3-methylimidazolium tetrafluoroborate, [BMIM][BF4] and 1-(1-butyl)-3-methylimidazolium hexafluorophosphate, [BMIM][PF6], are excessively widespread, their SP, SdP, SA, and SB values are measured herein at temperatures from 293 to 353 K. Four key points are emphasized herein: (i) the origin of the solvatochromic solvent scales--the gas phase, that is the absence of any medium perturbation--; (ii) the separation of the polarizability and dipolarity effects; (iii) the simplification of the probing process in order to obtain the solvatochromic parameters; and (iv) the SP, SdP, SA, and SB solvent scales can probe the polarizability, dipolarity, acidity, and basicity of ionic liquids as well as of organic solvents and water-organic solvent mixtures. From the multiparameter approach using the four pure solvent scales one can draw the conclusion that (a) the solvent influence of [BMIM][BF4] parallels that of formamide at 293 K, both of them miscible with water; (b) [BMIM][PF6] shows a set of solvatochromic parameters similar to that of chloroacetonitrile, both of them water insoluble; and (c) that the corresponding solvent acidity and basicity of the ionic liquids can be explained to a great extent from the cation species by comparing the empirical parameters of [BMIM](+) with those of the solvent 1-methylimidazole. The insolubility of [BMIM][PF6] in water as compared to [BMIM][BF4] is tentatively connected to some extent to the larger molar volume of the anion [PF6](-), and to the difference in basicity of [PF6](-) and [BF4](-).

  20. Quantification of interaction and topological parameters of polyisoprene star polymers under good solvent conditions.

    Science.gov (United States)

    Rai, Durgesh K; Beaucage, Gregory; Ratkanthwar, Kedar; Beaucage, Peter; Ramachandran, Ramnath; Hadjichristidis, Nikos

    2016-05-01

    Mass fractal scaling, reflected in the mass fractal dimension d_{f}, is independently impacted by topology, reflected in the connectivity dimension c, and by tortuosity, reflected in the minimum dimension d_{min}. The mass fractal dimension is related to these other dimensions by d_{f}=cd_{min}. Branched fractal structures have a higher mass fractal dimension compared to linear structures due to a higher c, and extended structures have a lower dimension compared to convoluted self-avoiding and Gaussian walks due to a lower d_{min}. It is found, in this work, that macromolecules in thermodynamic equilibrium display a fixed mass fractal dimension d_{f} under good solvent conditions, regardless of chain topology.  These equilibrium structures accommodate changes in chain topology such as branching c by a decrease in chain tortuosity d_{min}. Symmetric star polymers are used to understand the structure of complex macromolecular topologies. A recently published hybrid Unified scattering function accounts for interarm correlations in symmetric star polymers along with polymer-solvent interaction for chains of arbitrary scaling dimension. Dilute solutions of linear, three-arm and six-arm polyisoprene stars are studied under good solvent conditions in deuterated p-xylene. Reduced chain tortuosity can be viewed as steric straightening of the arms. Steric effects for star topologies are quantified, and it is found that steric straightening of arms is more significant for lower-molecular-weight arms. The observation of constant d_{f} is explained through a modification of Flory-Krigbaum theory for branched polymers.

  1. The effect of organic solvents on enzyme kinetic parameters of human CYP3A4 and CYP1A2 in vitro.

    Science.gov (United States)

    Rokitta, Dennis; Pfeiffer, Kay; Streich, Christina; Gerwin, Henrik; Fuhr, Uwe

    2013-10-01

    Abstract Enzyme kinetic parameters provide essential quantitative information about characterization of individual steps in drug metabolism. Such enzymes are located in a (partially) aqueous environment. For in vitro measurements potential lipophilic substrates regularly require organic solvents to achieve concentrations sufficient for access of the drug to the binding site of the enzyme. However, solvents may interact with the enzymes. In this study, we investigated the effects of methanol, ethanol, acetonitrile and dimethyl sulfoxide (1% to 4%) on the assessment of km, Vmax and Clint for the metabolism of midazolam via CYP3A4 to 1-hydroxymidazolam and the metabolism of caffeine to paraxanthine via CYP1A2 using expressed enzymes in vitro. The presence of acetonitrile proved the highest apparent Vmax value for paraxanthine formation but the lowest values for 1-hydroxymidazolam formation. The km value for midazolam showed no systematic effects of organic solvents, while for caffeine km was up to 8-fold lower for solvent free samples compared to solvent containing samples. The present example suggests that effects of solvents may considerably influence enzyme kinetic parameters beyond a mere change in apparent activity. These effects illustrate a difference for individual enzyme--substrate pairs, solvents, and solvent concentrations. What remains is the determination to which extent these effects compromise in vitro-in vivo extrapolations, and which solvents are most appropriate.

  2. Cell density and solvent are critical parameters affecting formazan evaluation in MTT assay

    Directory of Open Access Journals (Sweden)

    Kellen Cristina da Silva Gasque

    2014-06-01

    Full Text Available The aim of this study was to establish the more accurate protocol for fibroblast cell viability using MTT assay. NIH/3T3 fibroblasts were seeded at the following cell densities: 3.125x10³; 1.156x10(4; 3.125x10(4; 1.156x10(5 and 3.125x10(5 cells/cm². Following 24h of seeding, MTT was added to the wells. After 4h of the MTT addition, different solvents were added to solubilize the formazan crystals: 1 HCl/SDS group- 20% SDS and 0.01 M HCl; 2 EtOH/ HAc group-50% ethanol and 1% acetic acid; 3 DMSO group- 99.5% dimethyl sulfoxide; and 4 PropOH group- 99.5% isopropanol. The absorbance values were measured using a spectrophotometer at 570 nm. The data were analyzed by 2-way ANOVA (p<0.05 and showed that the absorbance average varied according to the number of cells and solvents: HCl/SDS (0 to 0.13, EtOH/HAc (0 to 0.22, DMSO (0.76 to 1.31 and PropOH (0.66 to 1.04. The DMSO and PropOH groups presented the most appropriate protocols for NIH/3T3 fibroblasts cell viability, especially at the density of 1.156x10(4 cells/cm².

  3. AIE Based Coumarin Chromophore - Evaluation and Correlation Between Solvatochromism and Solvent Polarity Parameters.

    Science.gov (United States)

    Lanke, Sandip K; Sekar, Nagaiyan

    2016-03-01

    A new class of red emitting extensively conjugated donor-π-acceptor type dyes bearing coumarin units have been synthesized by condensation of 7-(diethylamino)-2-oxo-2 H-chromene-3-carbaldehyde with different active methylenes. All the dyes are characterized by (1)H NMR, (13)C NMR and HRMS spectroscopy. The photophysical behaviour and the relation between structure and properties of the coumarin "push-pull" derivatives were investigated experimentally. The dyes exhibited positive solvatochromism and solvatofluorism in solution of varying polarity. These coumarin dyes show aggregation induced emission properties with red emitting fluorescence. They show absorption in the range of 501-528 and emission in the range of 547-630 nm. We evaluated photophysical properties of coumarin dyes using solvotochromism and solvent dependent shift in the emission wavelength. All the synthesized coumarin dyes COS1-COS4 are showing very good solvatochromic properties.

  4. pH-induced gene regulation of solvent production by Clostridium acetobutylicum in continuous culture: Parameter estimation and sporulation modelling

    Science.gov (United States)

    Thorn, Graeme J.; King, John R.; Jabbari, Sara

    2013-01-01

    The acetone–butanol (AB) fermentation process in the anaerobic endospore-forming Gram-positive bacterium Clostridium acetobutylicum is useful as a producer of biofuels, particularly butanol. Recent work has concentrated on trying to improve the efficiency of the fermentation method, either through changes in the environmental conditions or by modifying the genome to selectively favour the production of one particular solvent over others. Fermentation of glucose by C. acetobutylicum occurs in two stages: initially the acids acetate and butyrate are produced and excreted and then, as the external pH falls, acetate and butyrate are ingested and further metabolised into the solvents acetone, butanol and ethanol. In order to optimise butanol production, it is important to understand how pH affects the enzyme-controlled reactions in the metabolism process. We adapt an ordinary differential equation model of the metabolic network with regulation at the genetic level for the required enzymes; parametrising the model using experimental data generated from continuous culture, we improve on previous point predictions (S. Haus, S. Jabbari, T. Millat, H. Janssen, R.-J. Fisher, H. Bahl, J. R. King, O. Wolkenhauer, A systems biology approach to investigate the effect of pH-induced gene regulation on solvent production by Clostridium acetobutylicum in continuous culture, BMC Systems Biology 5 (2011)) [1] both by using a different optimisation approach and by computing confidence intervals and correlation coefficients. We find in particular that the parameters are ill-determined from the data and that two separate clusters of parameters appear correlated, reflecting the importance of two metabolic intermediates. We extend the model further to include another aspect of the clostridial survival mechanism, sporulation, and by computation of the Akaike Information Criterion values find that the there is some evidence for the presence of sporulation during the shift. PMID:23201580

  5. pH-induced gene regulation of solvent production by Clostridium acetobutylicum in continuous culture: parameter estimation and sporulation modelling.

    Science.gov (United States)

    Thorn, Graeme J; King, John R; Jabbari, Sara

    2013-02-01

    The acetone-butanol (AB) fermentation process in the anaerobic endospore-forming Gram-positive bacterium Clostridium acetobutylicum is useful as a producer of biofuels, particularly butanol. Recent work has concentrated on trying to improve the efficiency of the fermentation method, either through changes in the environmental conditions or by modifying the genome to selectively favour the production of one particular solvent over others. Fermentation of glucose by C. acetobutylicum occurs in two stages: initially the acids acetate and butyrate are produced and excreted and then, as the external pH falls, acetate and butyrate are ingested and further metabolised into the solvents acetone, butanol and ethanol. In order to optimise butanol production, it is important to understand how pH affects the enzyme-controlled reactions in the metabolism process. We adapt an ordinary differential equation model of the metabolic network with regulation at the genetic level for the required enzymes; parametrising the model using experimental data generated from continuous culture, we improve on previous point predictions (S. Haus, S. Jabbari, T. Millat, H. Janssen, R.-J. Fisher, H. Bahl, J. R. King, O. Wolkenhauer, A systems biology approach to investigate the effect of pH-induced gene regulation on solvent production by Clostridium acetobutylicum in continuous culture, BMC Systems Biology 5 (2011)) [1] both by using a different optimisation approach and by computing confidence intervals and correlation coefficients. We find in particular that the parameters are ill-determined from the data and that two separate clusters of parameters appear correlated, reflecting the importance of two metabolic intermediates. We extend the model further to include another aspect of the clostridial survival mechanism, sporulation, and by computation of the Akaike Information Criterion values find that the there is some evidence for the presence of sporulation during the shift. Copyright © 2012

  6. Determination of solubility parameters and thermodynamic properties in hydrocarbon-solvent systems by gas chromatography

    Directory of Open Access Journals (Sweden)

    E. Díaz

    2007-06-01

    Full Text Available Gas chromatography used to calculate the specific retention volume of several hydrocarbons in different chromatographic liquid phases (Squalane, Carbowax-400, Carbowax-1500, Carbowax-4000, Amine-220, Dinonyl phthalate, Tributyl phosphate and Trixylenyl phosphate. Some thermodynamic parameters, such as enthalpy of sorption and Flory-Huggins parameters relating the interaction between liquid phases and solutes, were also calculated from the determined retention volumes. Liquid phase solubility parameters of Squalane, Carbowax-400, Carbowax-1500 and Carbowax-4000 at 80 ºC as well as the polar and apolar components were calculated too. A new model was proposed to correlate polar contribution to the solubility parameter of a liquid phase with the specific retention volume of a solute in this liquid phase.

  7. Solubility parameter of drugs for predicting the solubility profile type within a wide polarity range in solvent mixtures.

    Science.gov (United States)

    Peña, M A; Reíllo, A; Escalera, B; Bustamante, P

    2006-09-14

    The solubility enhancement produced by two binary mixtures with a common cosolvent (ethanol-water and ethyl acetate-ethanol) was studied against the solubility parameter of the mixtures (delta1) to characterize different types of solubility profiles. Benzocaine, salicylic acid and acetanilide show a single peak in the least polar mixture (ethanol-ethyl acetate) at delta1=22.59, 21.70 and 20.91 MPa1/2, respectively. Phenacetin displays two solubility maxima, at delta1=25.71 (ethanol-water) and at delta1=23.30 (ethyl acetate-ethanol). Acetanilide shows an inflexion point in ethanol-water instead of a peak, and the sign of the slope does not vary when changing the cosolvent. The solubility profiles were compared to those obtained in dioxane-water, having a solubility parameter range similar to that covered with the common cosolvent system. All the drugs reach a maximum at about 90% dioxane (delta1=23 MPa1/2). A modification of the extended Hildebrand method is applicable for curves with a single maximum whereas a model including the Hildebrand solubility parameter delta1 and the acidic partial solubility parameter delta1a is required to calculate more complex solubility profiles (with inflexion point or two maxima). A single equation was able to fit the solubility curves of all drugs in the common cosolvent system. The polarity of the drug is related to the shape of the solubility profile against the solubility parameter delta1 of the solvent mixtures. The drugs with solubility parameters below 24 MPa1/2 display a single peak in ethanol-ethyl acetate. The drugs with delta2 values above 25 MPa1/2 show two maxima, one in each solvent mixture (ethanol-water and ethanol-ethyl acetate). The position of the maximum in ethanol-ethyl acetate shifts to larger polarity values (higher delta1 values) as the solubility parameter of the drug delta2 increases.

  8. The solvatochromic, spectral, and geometrical properties of nifenazone: a DFT/TD-DFT and experimental study.

    Science.gov (United States)

    Bani-Yaseen, Abdulilah Dawoud; Al-Balawi, Mona

    2014-08-07

    The solvatochromic, spectral, and geometrical properties of nifenazone (NIF), a pyrazole-nicotinamide drug, were experimentally and computationally investigated in several neat solvents and in hydro-organic binary systems such as water-acetonitrile and water-dioxane systems. The bathochromic spectral shift observed in NIF absorption spectra when reducing the polarity of the solvent was correlated with the orientation polarizability (Δf). Unlike aprotic solvents, a satisfactory correlation between λ(max) and Δf was determined (linear correlation of regression coefficient, R, equal to 0.93) for polar protic solvents. In addition, the medium-dependent spectral properties were correlated with the Kamlet-Taft solvatochromic parameters (α, β, and π*) by applying a multiple linear regression analysis (MLRA). The results obtained from this analysis were then employed to establish MLRA relationships for NIF in order to estimate the spectral shift in different solvents, which in turn exhibited excellent correlation (R > 0.99) with the experimental values of ν(max). Density functional theory (DFT) and time-dependent DFT theory calculations coupled with the integral equation formalism-polarizable continuum model (IEF-PCM) were performed to investigate the solvent-dependent spectral and geometrical properties of NIF. The calculations showed good and poor agreements with the experimental results using the CAM-B3LYP and B3LYP functionals, respectively. Experimental and theoretical results confirmed that the chemical properties of NIF are strongly dependent on the polarity of the chosen medium and its hydrogen bonding capability. This in turn supports the hypothesis of the delocalization of the electron density within the pyrazole ring of NIF.

  9. Synthesis, characterization and photophysical studies of a novel schiff base bearing 1, 2, 4-Triazole scaffold

    Science.gov (United States)

    Alphonse, Roshmy; Varghese, Anitha; George, Louis

    2016-06-01

    A novel Schiff base derivative containing 1, 2, 4-triazole nucleus (TMPIMP) was synthesized from 4- [1,2,4] triazol-1-ylmethyl-phenylamine and salicylaldehyde in the presence of glacial acetic acid in an ethanolic medium. The synthesized compound was characterized by 1H-NMR, IR and UV spectral analysis. The excitation and emission spectra of triazolyl methyl phenyl imino methyl phenol (abbreviated as TMPIMP) were recorded in various solvents to investigate their solvatochromic behaviour. Dipole moments of the two electronic states of TMPIMP were calculated from solvatochromic spectral shifts. These were correlated with refractive index (η) and dielectric constant (ε) of various solvents. Theoretical calculations were performed to estimate the excited state dipole moment on the basis of different solvent correlation methods, like the Bilot-Kawski, Bakhshiev, Lippert-Mataga, Kawski-Chamma-Viallet and Reichardt methods. The dipole moment in the excited state was found to be higher than that in the ground state due to a substantial redistribution of electron densities and charges. Using a multiple regression analysis, the solvent-solute interactions were determined by means of Kamlet Taft parameters (α, β, π*). Computational studies were performed by Gaussian 09 W software using a time-dependent density functional theory (TD-DFT) in order to calculate the atomic charges and frontier molecular orbital energies in the solvent phase. The calculations indicated that the dipole moment of the molecule in an excited state is much higher than that in a ground state. The chemical stability of TMPIMP was determined by means of chemical hardness (η) using HOMO-LUMO energies. The reactive centers in the molecule were also identified by molecular electrostatic potential (MESP) 3D plots as a result of TD-DFT computational analysis.

  10. Dendritic biomimicry: microenvironmental hydrogen-bonding effects on tryptophan fluorescence.

    Science.gov (United States)

    Koenig, S; Müller, L; Smith, D K

    2001-03-02

    Two series of dendritically modified tryptophan derivatives have been synthesised and their emission spectra measured in a range of different solvents. This paper presents the syntheses of these novel dendritic structures and discusses their emission spectra in terms of both solvent and dendritic effects. In the first series of dendrimers, the NH group of the indole ring is available for hydrogen bonding, whilst in the second series, the indole NH group has been converted to NMe. Direct comparison of the emission wavelengths of analogous NH and NMe derivatives indicates the importance of the Kamlet-Taft solvent beta3 parameter, which reflects the ability of the solvent to accept a hydrogen bond from the NH group, an effect not possible for the NMe series of dendrimers. For the NH dendrimers, the attachment of a dendritic shell to the tryptophan subunit leads to a red shift in emission wavelength. This dendritic effect only operates in non-hydrogen-bonding solvents. For the NMe dendrimers, however, the attachment of a dendritic shell has no effect on the emission spectra of the indole ring. This proves the importance of hydrogen bonding between the branched shell and the indole NH group in causing the dendritic effect. This is the first time a dendritic effect has been unambiguously assigned to individual hydrogen-bonding interactions and indicates that such intramolecular interactions are important in dendrimers, just as they are in proteins. Furthermore, this paper sheds light on the use of tryptophan residues as a probe of the microenvironment within proteins--in particular, it stresses the importance of hydrogen bonds formed by the indole NH group.

  11. Effects of homogenization process parameters on physicochemical properties of astaxanthin nanodispersions prepared using a solvent-diffusion technique.

    Science.gov (United States)

    Anarjan, Navideh; Jafarizadeh-Malmiri, Hoda; Nehdi, Imededdine Arbi; Sbihi, Hassen Mohamed; Al-Resayes, Saud Ibrahim; Tan, Chin Ping

    2015-01-01

    Nanodispersion systems allow incorporation of lipophilic bioactives, such as astaxanthin (a fat soluble carotenoid) into aqueous systems, which can improve their solubility, bioavailability, and stability, and widen their uses in water-based pharmaceutical and food products. In this study, response surface methodology was used to investigate the influences of homogenization time (0.5-20 minutes) and speed (1,000-9,000 rpm) in the formation of astaxanthin nanodispersions via the solvent-diffusion process. The product was characterized for particle size and astaxanthin concentration using laser diffraction particle size analysis and high performance liquid chromatography, respectively. Relatively high determination coefficients (ranging from 0.896 to 0.969) were obtained for all suggested polynomial regression models. The overall optimal homogenization conditions were determined by multiple response optimization analysis to be 6,000 rpm for 7 minutes. In vitro cellular uptake of astaxanthin from the suggested individual and multiple optimized astaxanthin nanodispersions was also evaluated. The cellular uptake of astaxanthin was found to be considerably increased (by more than five times) as it became incorporated into optimum nanodispersion systems. The lack of a significant difference between predicted and experimental values confirms the suitability of the regression equations connecting the response variables studied to the independent parameters.

  12. Solvent selection for matrix-assisted laser desorption/ionization time-of-flight mass spectrometric analysis of synthetic polymers employing solubility parameters.

    Science.gov (United States)

    Brandt, Heike; Ehmann, Thomas; Otto, Matthias

    2010-08-30

    The principle relating to the selection of a proper matrix, cationization reagent, and solvent for matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) of synthetic polymers is still a topic of research. In this work we focused on the selection of a suitable MALDI solvent. Polystyrene PS7600 and poly(ethylene glycol) PEG4820 were analyzed by MALDI-TOF MS using various solvents which were selected based on the Hansen solubility parameter system. For polystyrene (PS), dithranol was used as the matrix and silver trifluoroacetate as the cationization reagent whereas, for poly(ethylene glycol) (PEG), the combination of 2,5-dihydroxybenzoic acid and sodium trifluoroacetate was used for all experiments. When employing solvents which dissolve PS and PEG, reliable MALDI mass spectra were obtained while samples in non-solvents (solvents which are not able to dissolve the polymer) failed to provide spectra. It seems that the solubility of the matrix and the cationization reagent are less important than the polymer solubility.

  13. A phenomenological one-parameter equation of state for osmotic pressures of PEG and other neutral flexible polymers in good solvents

    DEFF Research Database (Denmark)

    Cohen, J.A.; Podgornik, R; Hansen, Per Lyngs;

    2009-01-01

    We present a phenomenological one-parameter scaling equation of state that accurately represents osmotic pressures of neutral flexible polymers in good solvents from the dilute through the semidilute regime. The equation comprises a sum of scaled van't Hoff and des Cloizeaux terms including a fit...

  14. Parâmetros reacionais para a síntese enzimática do butirato de butila em solventes orgânicos Reactional parameters for enzymatic synthesis of butyl butyrate in organic solvent

    Directory of Open Access Journals (Sweden)

    Heizir F. CASTRO

    1997-12-01

    Full Text Available A síntese orgânica catalisada por enzimas envolve um mecanismo complexo dependente do tipo de substrato, enzima, solvente orgânico e teor de água no meio reacional. Neste trabalho foi estudado a influência de alguns desses parâmetros no rendimento da esterificação do butanol com ácido butírico, utilizando uma preparação enzimática comercial de lipase. A polaridade e natureza do solvente, bem como a razão molar entre o butanol e ácido butírico, foram considerados os fatores que mais influenciaram o desenvolvimento dessa síntese enzimática.The organic synthesis catalyzed by enzymes is a complex function of substrate concentration, water concentration in the liquid phase, enzyme and organic solvent properties. In this work the influence of some parameters on the esterification of butanol with butyric acid was investigated, using a commercial lipase preparation. The polarity and nature of the solvent and also the substrate mole ratios played an important role in the performance of this enzymatic synthesis.

  15. Effects of homogenization process parameters on physicochemical properties of astaxanthin nanodispersions prepared using a solvent-diffusion technique

    Directory of Open Access Journals (Sweden)

    Anarjan N

    2015-02-01

    Full Text Available Navideh Anarjan,1 Hoda Jafarizadeh-Malmiri,2 Imededdine Arbi Nehdi,3 Hassen Mohamed Sbihi,3 Saud Ibrahim Al-Resayes,3 Chin Ping Tan4 1Young Researchers And Elite Club, Tabriz Branch, Islamic Azad University, Tabriz, Iran; 2Department of Chemical Engineering, Faculty of Food Engineering, Sahand University of Technology, Tabriz, Iran; 3King Saud University, College of Science, Chemistry Department, Riyadh, Saudi Arabia; 4Department of Food Technology, Faculty of Food Science and Technology, Universiti Putra Malaysia, Selangor, Malaysia Abstract: Nanodispersion systems allow incorporation of lipophilic bioactives, such as astaxanthin (a fat soluble carotenoid into aqueous systems, which can improve their solubility, bioavailability, and stability, and widen their uses in water-based pharmaceutical and food products. In this study, response surface methodology was used to investigate the influences of homogenization time (0.5–20 minutes and speed (1,000–9,000 rpm in the formation of astaxanthin nanodispersions via the solvent-diffusion process. The product was characterized for particle size and astaxanthin concentration using laser diffraction particle size analysis and high performance liquid chromatography, respectively. Relatively high determination coefficients (ranging from 0.896 to 0.969 were obtained for all suggested polynomial regression models. The overall optimal homogenization conditions were determined by multiple response optimization analysis to be 6,000 rpm for 7 minutes. In vitro cellular uptake of astaxanthin from the suggested individual and multiple optimized astaxanthin nanodispersions was also evaluated. The cellular uptake of astaxanthin was found to be considerably increased (by more than five times as it became incorporated into optimum nanodispersion systems. The lack of a significant difference between predicted and experimental values confirms the suitability of the regression equations connecting the response

  16. Impact of quality parameters on the recovery of putrescine and cadaverine in fish using methanol-hydrochloric acid solvent extraction.

    Science.gov (United States)

    Richard, Nicole L; Pivarnik, Lori F; Ellis, P Christopher; Lee, Chong M

    2011-01-01

    Methanol (MeOH) extraction by AOAC Official Method 996.07 has resulted in low amine recoveries in fresh fish tissue. Addition of 25% 0.4 M HCl to the 75% methanol-water extraction solvent resulted in higher recoveries of putrescine and cadaverine. Average putrescine recovery increased from 55 to 92% in flounder, scup, bluefish, and salmon; from 92 to 98% in mackerel; and from 83 to 107% in processed mackerel. Average cadaverine recovery increased from 57 to 95% in flounder, scup, bluefish, and salmon; from 91 to 97% in mackerel; and from 92 to 108% in processed mackerel. Fish stored on ice for 12 days also showed differences between background concentrations determined with the two solvents. However, the values decreased with storage time, indicating that degradation of the protein matrix may cause more comparable measurements between the two solvents. However, consistently higher putrescine and cadaverine measurements were determined using MeOH-HCl. Although significant differences in the extraction of amines from the high-fat fish tissue were not seen between MeOH and MeOH-HCl, it would be ideal to have one solvent for biogenic amine extraction. This study confirms that MeOH-HCl is a better solvent for complete extraction and recovery of putrescine and cadaverine in fresh and processed fish tissues.

  17. Equilibrium Copper Strip Points as a Function of Temperature and Other Operating Parameters: Implications for Commercial Copper Solvent Extraction Plants

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    The development of pressure and bioleaching processes for high grade copper ores and concentrates will result in copper solvent extraction plants treating solutions with high copper and acid concentrations at temperatures up to 45C and these copper solvent extraction plants will run with reagent concentrations up to 40 vol.%. There is also a trend to use copper stripping solutions with less acid than typically used in recent years. Cognis has developed a model that accurately predicts the copper strip point for virtually any copper solvent extraction reagent or combination of reagents under a wide variety of conditions. The equilibrium strip points for several well known commercial copper solvent extraction reagents are given as a function of reagent concentration, the copper and acid concentration of the strip aqueous, and the temperature. It is shown that the equilibrium strip point is not a straight line function of reagent concentration and that the equilibrium strip point increases with an increase in temperature. Copper extraction also increases as the temperature increases.

  18. Solvents in novolak synthesis

    Science.gov (United States)

    Sobodacha, Chet J.; Lynch, Thomas J.; Durham, Dana L.; Paradis, Valerie R.

    1993-09-01

    Novolac resins may be prepared with or without a solvent present. We have found that solvent power greatly affects the properties of the finished resin and thus gives the resist chemist another variable with which to `fine-tune' resist properties. Using designed experiments, we investigated the effect of solvent power, as measured by Hansen's Solubility Parameters, of a number of solvents and solvent mixtures on the final properties of the novolac resin. We found that the relative molecular weight (RMW) and dissolution rate of a novolac resin can be varied by selection of a solvent or solvent mixture with the appropriate polarity and hydrogen- bonding characteristics. The solvent polarity and hydrogen-bonding characteristics may affect the stability of the cresol/formaldehyde transition state, thus causing the observed changes in RMW and dissolution rate.

  19. Solvent effect on absorption and fluorescence spectra of three biologically active carboxamides (C1, C2 and C3). Estimation of ground and excited state dipole moment from solvatochromic method using solvent polarity parameters.

    Science.gov (United States)

    Patil, N R; Melavanki, R M; Kapatkar, S B; Ayachit, N H; Saravanan, J

    2011-05-01

    The absorption and fluorescence spectra of three Carboxamides namely (E)-2-(4-Chlorobenzylideneamino)-N-(2-chlorophenyl)-4,5,6,7-tetrahydrobenzo[b]thiophene-3-carboxamide (C(1)), (E)-N-(3-Chlorophenyl)-2-(3, 4-dimethoxybenzylideneamino)-4,5,6,7-tetrahydrobenzo[b]thiophene-3-carboxamide (C(2)) and (E)-N-(3-Chlorophenyl)-2-(3,4,5-trimethoxybenzylideneamino)-4,5,6,7-tetrahydrobenzo[b]thiophene-3-carboxamide (C(3)) have been recorded at room temperature in solvents of different polarities using dielectric constant (ε) and refractive index (n). Experimental ground (μ(g)) and excited (μ(e)) state dipole moments are estimated by means of solvatochromic shift method and also the excited dipole moments are estimated in combination with ground state dipole moments. It was estimated that dipole moments of the excited state were higher than those of the ground state of all three molecules. Further, the changes in dipole moment (Δμ) were calculated both from solvatochromic shift method and on the basis of microscopic empirical solvent polarity parameter (E(N)(T)) and the values are compared.

  20. Photophysical and photochemical parameters of octakis (benzylthio) phthalocyaninato zinc, aluminium and tin: Red shift index concept in solvent effect on the ground state absorption of zinc phthalocyanine derivatives

    Science.gov (United States)

    Akpe, Victor; Brismar, Hjalmar; Nyokong, Tebello; Osadebe, P. O.

    2010-12-01

    This paper addresses the synthesis of octa-substituted benzylthio metallophthalocyanines (OBTMPcs) that contain the central metal ions of Zn 2+, Al 3+ and Sn 4+. The ground state absorption of ZnPc(SR) 8 (OBTZnPc) along with the ZnPc derivatives, well documented in literature were used to study a new concept called the red shift index ( R sI ). The concept is based on the empirical values of R sI of the different complexes in solvent media. Unequivocally, parameters used in this paper show strong correlations that are consistent with the results obtained. For instance, R sI of the complexes tend to increase as the refractive index, n D, and solvent donor, DN, of solvent increases. Photodegradation (photobleaching) quantum yield, ϕ d measurements of these compounds show that they are highly photostable, ϕ d (0.03-0.33 × 10 -5). The triplet quantum yield, ϕ T (0.40-0.53) and the triplet lifetime, τ T (610-810 μs) are within the typical range for metallophthalocyanines in DMSO. The photosensitisation efficiency, SΔ, is relatively high for all the molecules (0.74-0.90).

  1. Solvent systems with n-hexane and/or cyclohexane in countercurrent chromatography--Physico-chemical parameters and their impact on the separation of alkyl hydroxybenzoates.

    Science.gov (United States)

    Englert, Michael; Vetter, Walter

    2014-05-16

    Countercurrent chromatography (CCC) is an efficient preparative separation technique based on the liquid-liquid distribution of compounds between two phases of a biphasic liquid system. The crucial parameter for the successful application is the selection of the solvent system. Especially for nonpolar analytes the selection options are limited. On the search for a suitable solvent system for the separation of an alkyl hydroxybenzoate homologous series, we noted that the substitution of cyclohexane with n-hexane was accompanied with unexpected differences in partitioning coefficients of the individual analytes. In this study, we investigated the influence of the subsequent substitution of n-hexane with cyclohexane in the n-hexane/cyclohexane/tert-butylmethylether/methanol/water solvent system family. Exact phase compositions and polarity, viscosity and density differences were determined to characterize the different mixtures containing n-hexane and/or cyclohexane. Findings were confirmed by performing CCC separations with different mixtures, which led to baseline resolution for positional isomers when increasing the amount of cyclohexane while the resolution between two pairs of structural isomers decreased. With the new methodology described, structurally similar compounds could be resolved by choosing a certain ratio of n-hexane to cyclohexane.

  2. Determination of Parameters for the Supercritical Extraction of Antioxidant Compounds from Green Propolis Using Carbon Dioxide and Ethanol as Co-Solvent

    Science.gov (United States)

    Barreto, Gabriele de Abreu; Costa, Samantha Serra; Silva, Rejane Pina Dantas; da Silva, Danielle Figuerêdo; Brandão, Hugo Neves; da Rocha, José Luiz Carneiro; Nunes, Silmar Baptista; Umsza-Guez, Marcelo Andres

    2015-01-01

    The aim of this study was to determine the best processing conditions to extract Brazilian green propolis using a supercritical extraction technology. For this purpose, the influence of different parameters was evaluated such as S/F (solvent mass in relation to solute mass), percentage of co-solvent (1 and 2% ethanol), temperature (40 and 50°C) and pressure (250, 350 and 400 bar) using supercritical carbon dioxide. The Global Yield Isotherms (GYIs) were obtained through the evaluation of the yield, and the chemical composition of the extracts was also obtained in relation to the total phenolic compounds, flavonoids, antioxidant activity and 3,5-diprenyl-4-hydroxicinnamic acid (Artepillin C) and acid 4-hydroxycinnamic (p-coumaric acid). The best results were identified at 50°C, 350 bar, 1% ethanol (co-solvent) and S/F of 110. These conditions, a content of 8.93±0.01 and 0.40±0.05 g/100 g of Artepillin C and p-coumaric acid, respectively, were identified indicating the efficiency of the extraction process. Despite of low yield of the process, the extracts obtained had high contents of relevant compounds, proving the viability of the process to obtain green propolis extracts with important biological applications due to the extracts composition. PMID:26252491

  3. Photophysical study of some 3-benzoylmethyleneindol-2-ones and estimation of ground and excited states dipole moments from solvatochromic methods using solvent polarity parameters

    Science.gov (United States)

    Saroj, Manju K.; Sharma, Neera; Rastogi, Ramesh C.

    2012-03-01

    3-Benzoylmethyleneindol-2-ones, isatin based chalcones containing donor and acceptor moieties that exhibit excited-state intramolecular charge transfer, have been studied in different solvents by absorption and emission spectroscopy. The excited state behavior of these compounds is strongly dependent on the nature of substituents and the environment. These compounds show multiple emissions arising from a locally excited state and the two states due to intramolecular processes viz. intramolecular charge transfer (ICT) and excited state intramolecular proton transfer (ESIPT). Excited-state dipole moments have been calculated using Stoke-shifts of LE and ICT states using solvatochromic methods. The higher values of dipole moments obtained lead to support the formation of ICT state as one of the prominent species in the excited states of all 3-benzoylmethyleneindol-2-ones. The correlation of the solvatochromic Stokes-shifts with the microscopic solvent polarity parameter (ETN) was found to be superior to that obtained using bulk solvent polarity functions. The absorption and florescence spectral characteristics have been also investigated as a function of acidity and basicity (Ho/pH) in aqueous phase.

  4. Inter-channel effects in monosolvated atomic iodide cluster anion detachment: correlation of the anisotropy parameter with solvent dipole moment.

    Science.gov (United States)

    Mbaiwa, Foster; Dao, Diep; Holtgrewe, Nicholas; Lasinski, Joshua; Mabbs, Richard

    2012-03-21

    Photoelectron imaging results are presented for I(-)[middle dot]X cluster anions (X = CO(2), C(4)H(5)N [pyrrole], (CH(3))(2)CO, CH(3)NO(2)). The available detachment channels are labeled according to the neutral iodine atom states produced (channel I ≡ (2)P(3/2) and channel II ≡ (2)P(1/2)). At photon energies in the vicinity of the channel II threshold these data are compared to previously reported results for I(-)[middle dot]X (X = CH(3)CN, CH(3)Cl, CH(3)Br, and H(2)O). In particular, these results show a strong connection between the dipole moment of the solvent molecule and the behavior of the channel I photoelectron angular distributions in this region, which is consistent with an electronic autodetachment process. The evolution of the channel II:channel I branching ratios in this excitation regime supports this contention.

  5. Inter-channel effects in monosolvated atomic iodide cluster anion detachment: Correlation of the anisotropy parameter with solvent dipole moment

    Science.gov (United States)

    Mbaiwa, Foster; Dao, Diep; Holtgrewe, Nicholas; Lasinski, Joshua; Mabbs, Richard

    2012-03-01

    Photoelectron imaging results are presented for I-.X cluster anions (X = CO2, C4H5N [pyrrole], (CH3)2CO, CH3NO2). The available detachment channels are labeled according to the neutral iodine atom states produced (channel I ≡ 2P3/2 and channel II ≡ 2P1/2). At photon energies in the vicinity of the channel II threshold these data are compared to previously reported results for I-.X (X = CH3CN, CH3Cl, CH3Br, and H2O). In particular, these results show a strong connection between the dipole moment of the solvent molecule and the behavior of the channel I photoelectron angular distributions in this region, which is consistent with an electronic autodetachment process. The evolution of the channel II:channel I branching ratios in this excitation regime supports this contention.

  6. Rational Design of Particle Mesh Ewald Compatible Lennard-Jones Parameters for +2 Metal Cations in Explicit Solvent.

    Science.gov (United States)

    Li, Pengfei; Roberts, Benjamin P; Chakravorty, Dhruva K; Merz, Kenneth M

    2013-06-11

    Metal ions play significant roles in biological systems. Accurate molecular dynamics (MD) simulations on these systems require a validated set of parameters. Although there are more detailed ways to model metal ions, the nonbonded model, which employs a 12-6 Lennard-Jones (LJ) term plus an electrostatic potential is still widely used in MD simulations today due to its simple form. However, LJ parameters have limited transferability due to different combining rules, various water models and diverse simulation methods. Recently, simulations employing a Particle Mesh Ewald (PME) treatment for long-range electrostatics have become more and more popular owing to their speed and accuracy. In the present work we have systematically designed LJ parameters for 24 +2 metal (M(II)) cations to reproduce different experimental properties appropriate for the Lorentz-Berthelot combining rules and PME simulations. We began by testing the transferability of currently available M(II) ion LJ parameters. The results showed that there are differences between simulations employing Ewald summation with other simulation methods and that it was necessary to design new parameters specific for PME based simulations. Employing the thermodynamic integration (TI) method and performing periodic boundary MD simulations employing PME, allowed for the systematic investigation of the LJ parameter space. Hydration free energies (HFEs), the ion-oxygen distance in the first solvation shell (IOD) and coordination numbers (CNs) were obtained for various combinations of the parameters of the LJ potential for four widely used water models (TIP3P, SPC/E, TIP4P and TIP4PEW). Results showed that the three simulated properties were highly correlated. Meanwhile, M(II) ions with the same parameters in different water models produce remarkably different HFEs but similar structural properties. It is difficult to reproduce various experimental values simultaneously because the nonbonded model underestimates the

  7. Hydration free energies using semiempirical quantum mechanical Hamiltonians and a continuum solvent model with multiple atomic-type parameters.

    Science.gov (United States)

    Anisimov, Victor M; Cavasotto, Claudio N

    2011-06-23

    To build the foundation for accurate quantum mechanical (QM) simulation of biomacromolecules in an aqueous environment, we undertook the optimization of the COnductor-like Screening MOdel (COSMO) atomic radii and atomic surface tension coefficients for different semiempirical Hamiltonians adhering to the same computational conditions recently followed in the simulation of biomolecular systems. This optimization was achieved by reproducing experimental hydration free energies of a set consisting of 507 neutral and 99 ionic molecules. The calculated hydration free energies were significantly improved by introducing a multiple atomic-type scheme that reflects different chemical environments. The nonpolar contribution was treated according to the scaled particle Claverie-Pierotti formalism. Separate radii and surface tension coefficient sets have been developed for AM1, PM3, PM5, and RM1 semiempirical Hamiltonians, with an average unsigned error for neutral molecules of 0.64, 0.66, 0.73, and 0.71 kcal/mol, respectively. Free energy calculation of each molecule took on average 0.5 s on a single processor. The new sets of parameters will enhance the quality of semiempirical QM calculations using COSMO in biomolecular systems. Overall, these results further extend the utility of QM methods to chemical and biological systems in the condensed phase.

  8. Role of solvent/non-solvent ratio on microsphere formation using the solvent removal method.

    Science.gov (United States)

    Godbee, J; Scott, E; Pattamunuch, P; Chen, S; Mathiowitz, E

    2004-03-01

    The importance of good solvent concentration in the non-solvent mixture and the non-solvent viscosity on the ability to form microspheres using solvent removal process was investigated. The higher the viscosity of the polymer solutions, the higher the concentration of good solvent needed in the nonsolvent mixture to produce microspheres. This finding was due to faster precipitation of the polymer phase. Also, the addition of a model drug, fluorescein isothiocyanate conjugated-labelled bovine serum albumin, to the polymer solution (10% poly-L-lactic acid:poly(fumaric-co-sebacic) anhydride in methylene chloride) resulted in an overall lower polymer solution viscosity (15.5 cP with fluorescein isothiocyanate conjugated-labelled bovine serum albumin as compared with 18.25 cP for blank polymer at 25 degrees C). Additionally, the effect of good solvent concentration on non-solvent viscosity was evaluated, and the viscosity decreased as the concentration of good solvent increased. The effect of good solvent concentration on the non-solvent mixture on sphere formation was of great importance. Microspheres would not form when the good polymer solvent (methylene chloride) in the non-solvent phase was too low (below 175 ml for poly-L-lactic acid or 150 ml for poly(D,L-lactidco-glycolid)) or was replaced by another good solvent such as ethyl acetate, even though the same viscosity was achieved. It was shown that the concentration of the good solvent in the non-solvent mixture was more of a controlling factor than the viscosity of the non-solvent mixture in microsphere formation and the findings support the conclusion that diffusion is the main controlling parameter in solvent removal.

  9. Solvent substitution

    Energy Technology Data Exchange (ETDEWEB)

    1990-01-01

    The DOE Environmental Restoration and Waste Management Office of Technology Development and the Air Force Engineering and Services Center convened the First Annual International Workshop on Solvent Substitution on December 4--7, 1990. The primary objectives of this joint effort were to share information and ideas among attendees in order to enhance the development and implementation of required new technologies for the elimination of pollutants associated with industrial use of hazardous and toxic solvents; and to aid in accelerating collaborative efforts and technology transfer between government and industry for solvent substitution. There were workshop sessions focusing on Alternative Technologies, Alternative Solvents, Recovery/Recycling, Low VOC Materials and Treatment for Environmentally Safe Disposal. The 35 invited papers presented covered a wide range of solvent substitution activities including: hardware and weapons production and maintenance, paint stripping, coating applications, printed circuit boards, metal cleaning, metal finishing, manufacturing, compliance monitoring and process control monitoring. This publication includes the majority of these presentations. In addition, in order to further facilitate information exchange and technology transfer, the US Air Force and DOE solicited additional papers under a general Call for Papers.'' These papers, which underwent review and final selection by a peer review committee, are also included in this combined Proceedings/Compendium. For those involved in handling, using or managing hazardous and toxic solvents, this document should prove to be a valuable resource, providing the most up-to-date information on current technologies and practices in solvent substitution. Individual papers are abstracted separated.

  10. Relationship between physicochemical parameters of alpha-amino acids and those of the chlorinated solvents in the case of the L/L partition as supra molecular complexes

    Energy Technology Data Exchange (ETDEWEB)

    Oana popescu, D.; Constantinescu, T.; Mutihac, L.

    1997-09-01

    In order to explain the dependence of the distribution coefficient (D) between water and three different chlorinated solvents (methylene chloride, chloroform and 1,2-dichloroethane) of some alpha-amino acids (leucine, tryptophane, phenylalanine, methionine, valine and isoleucine), as supramolecular complexes of [EC...R-CH-(NH{sub 3})-COOH]``+A``- type, (EC=18-C-6; A``-=the anion originated in tropaeoline 00), a correlation was established by means of a multilinear regression analysis performed between different characteristics of the alpha-amino acids and those of the solvents involved. This study evidence a good correlation (r>0.81) between some of the characteristics of alpha-amino acids (pi, pH, pKa{sub 2}), and of the solvent Sigma Beta``H{sub 2}, pi``H{sub 2} R``H{sub 2} or sigma alpha``H{sub 2}, just mentioned. (Author) 21 refs.

  11. Impact of flavour solvent (propylene glycol or triacetin) on vanillin, 5-(hydroxymethyl)furfural, 2,4-decadienal, 2,4-heptadienal, structural parameters and sensory perception of shortcake biscuits over accelerated shelf life testing.

    Science.gov (United States)

    Yang, Ni; Hort, Joanne; Linforth, Robert; Brown, Keith; Walsh, Stuart; Fisk, Ian D

    2013-11-15

    The influence of choice of flavour solvent, propylene glycol (PG) or triacetin (TA), was investigated during accelerated shelf life (ASL) testing of shortcake biscuits. Specifically, the differential effect on the stability of added vanillin, the natural baked marker compound 5-(hydroxymethyl)furfural (HMF), specific markers of oxidative rancidity (2,4-decadienal, 2,4-heptadienal), and the structural parameters of hardness and fracturability. Significantly more HMF was formed during baking of biscuits prepared with TA; these biscuits were also more stable to oxidative degradation and loss of vanillin during ageing than biscuits prepared with PG. Fresh TA biscuits were significantly more brittle than fresh PG biscuits. There was no impact of solvent choice on hardness. Sensory evaluation of hardness, vanilla flavour and oily off-note was tested during ASL testing. There was no significant impact of storage on sensory ratings for either the PG or TA biscuits.

  12. SELECTION OF POLYMER SOLVENTS AND NEW TWO-DIMENSIONAL SOLUBILITY PARAMETER%聚合物的溶剂选择与新的两维溶解度参数

    Institute of Scientific and Technical Information of China (English)

    俞春芳; 黑恩成; 刘国杰

    2001-01-01

    按照溶解度参数的新定义,建立了一个两维溶解度参数体系,它由物理和化学两个溶解度参数分量构成,这两个分量的拆分借鉴了Wiehe新近提出的原则.对每一种聚合物在不同液体中的溶解度实验数据作图表明,所有溶剂几乎都聚集在溶解度参数图的某一区域内,这个区域可用一椭圆表示.通过一个简单的加和规则,它能用来满意地预测混合溶剂的溶解能力,为聚合物选择溶剂提供了重要的依据.广泛的检验表明,新的两维溶解度参数要比Hansen三维溶解度参数更加可靠.%Based on the new definition of solubility parameter obtained by our previous work, a new two-dimensional solubility parameter consisted of the physical and chemical (solubility parameter) components has been established. The method proposed by Wiehe is used as a reference to divide the two components. From the profile of solubility data, it can be seen that all solvents are almost located within some area of solubility parameter diagram for every polymer. This area can be expressed by an ellipse, which provides an important basis for the selection of polymer solvents. Using a simple adding rule, it can be satisfactorily used to predict the solvency of mixing solvents. The results of extensive testing show that the new two-dimensional solubility parameter is more reliable than Hansen's three-dimensional solubility parameter for the selection of polymer solvents.

  13. 溶解度参数在混合溶剂处理铝塑复合物中的应用%Application of Mixed Solvent Solubility Parameter in the Separation of Aluminum and Plastic Composite

    Institute of Scientific and Technical Information of China (English)

    张素风; 梅星贤; 张璐璐

    2013-01-01

    Mixed solvents including benzene-ethanol-water, toluene-ethanol-water and styrene-ethanol-water were used as a separating agent to separate aluminum and plastic composite. The volume ratio of each component of the mixed solvent used for completely separating the aluminum and plastic composite was investigated; the solubility parameter range of the organic adhesive used in the composite could be obtained through calculating the solubility parameter of the mixed solvent. The results showed that the ideal range of solubility parameters of organic adhesive is 29.1 to 34.8; the required volume ratio of toluene is least when using toluene-ethanol-water solvent as the separating agent.%针对混合溶剂处理铝塑复合物工艺的研究,分别以苯-乙醇-水、甲苯-乙醇-水、苯乙烯-乙醇-水3种混合液作为分离剂进行铝塑分离实验.由于苯、甲苯、苯乙烯的溶解度参数相近,当铝塑完全分离时,考察不同分离剂各组分的体积比,通过混合溶剂溶解度参数计算公式得出各混合溶剂的溶解度参数.根据相似相溶原理,得出铝塑复合物间有机胶黏剂溶解度参数的理想范围.结果表明,3种混合溶剂处理铝塑复合物,当铝塑完全分离时,铝塑复合物间胶黏剂的溶解度参数范围为29.1 ~ 34.8;甲苯-乙醇-水混合溶剂作为分离剂,所需的甲苯体积比最小(20%).

  14. Kinetics, reactivity, initial-transition state analysis and thermodynamic parameters of base-catalyzed hydrolysis of coumalic acid in solvents with different polarities

    Directory of Open Access Journals (Sweden)

    Ezz A. Abu-Gharib

    2017-02-01

    Full Text Available Base-catalyzed hydrolysis of coumalic acid (COU in binary aqueous-methanol and aqueous-acetone mixtures has been studied kinetically at a temperature range from 283 to 313 K. Moreover, the change in the activation energy barrier of COU from water to water–methanol and water–acetone mixtures is estimated from the kinetic data. Solvent effects on reactivity trends have been analyzed into initial and transition state components by using transfer chemical potentials of the reactants and kinetic data. The transfer chemical potentials δmμθ for COU− anion are derived from solubility data from its calcium, cerium and lanthanum salts. The decrease in rate constant of the base hydrolysis reaction of COU as the percentage of methanol or acetone increases is dominated by transition state (TS. The base hydrolysis reaction of COU follows a rate law with kobs = k2[OH−] and the reaction mechanism was suggested. The high negative values of entropy of activation support the proposal mechanism, i.e. the investigated reaction takes place via the formation of an intermediate complex. Thus, the ring opening of the intermediate complex would be the rate controlling step.

  15. Parameters affecting incorporation and by-product formation during the production of structured phospholipids by lipase-catalyzed acidolysis in solvent free system

    DEFF Research Database (Denmark)

    Vikbjerg, Anders Falk; Mu, Huiling; Xu, Xuebing

    2005-01-01

    the influence of major factors and their relationships on a number of responses reflecting the turnover of main reactions as well as side reactions. The five factors, including enzyme dosage, reaction time, reaction temperature, substrate ratio (mol/mol caprylic acid/ PC) and water addition, were varied...... at three levels with two star points. All parameters besides water addition had an effect on the incorporation of caprylic acid into PC and lysophosphatidylcholine (LPC). Reaction time and enzyme dosage showed increased effect on incorporation into PC, while substrate ratio and reaction temperature showed...... opposite effect. The PC content decreased with increase of all parameters except for substrate ratio. Optimal conditions are recommended as enzyme dosage 40%, reaction temperature 55°C, water addition 1%, reaction time 70h, and substrate ratio 6 mol/mol caprylic acid/PC. Under these conditions...

  16. 超分子凝胶性质与溶剂参数关系的研究进展%Research Progress in the Correlation between Gelation Properties and Solvent Parameters

    Institute of Scientific and Technical Information of China (English)

    赵呈孝; 王海涛; 李敏

    2014-01-01

    为了能有效地开发功能性凝胶,人们对超分子凝胶机理做了大量研究。但目前的研究还局限于凝胶因子结构和外界环境等影响因素,而有关溶剂对超分子凝胶体系的影响规律还不十分清楚。本文将结合最新研究进展详细地讨论凝胶性质(如凝胶-溶胶转变温度(Tgel)、临界凝胶浓度(CGC)、凝胶流变学性质等)与溶剂参数(如ε、ET(30)、χ、δ、δd、δp、δh等)的关系,揭示溶剂影响凝胶性质的规律;在此基础上,进一步介绍了超分子凝胶行为预测模型:一维模型、Teas图模型和Hansen空间模型,并讨论了各模型的优缺点,以期为新型超分子凝胶体系的设计提供参考。%To enable the effective development of functional gels, much effort has been dedicated to elucidating the mechanism of gelation. However, most existing studies have considered only the influence of the chemical structure of the gelators and/or external environmental factors;the contribution of the solvent in the gelation procedure is not yet understood. In this review, to reveal the solvent effects, the relationship between the gelation properties (such as the gel-sol phase transition temperature (Tgel), the critical gelation concentration (CGC), and the gelation behaviors) and the solvent parameters (ε, ET(30),χ,δ,δd,δp,δh) is systematical y discussed, based on recent research progress. Moreover, some experimental models for predicting the solvent effects (such as the one-dimensional model, Teas plot model, and Hansen space models) are introduced and discussed;these models could provide a guide for the development of new supramolecular gel systems.

  17. Influence of the composition of the stationary and mobile phase on the retention factors and solvent strength parameters in RP chromatographic systems in which the Everett equation is valid

    Directory of Open Access Journals (Sweden)

    M. B. CELAP

    2001-10-01

    Full Text Available It is shown how in RPchromatography the Everett equation for ideal phase equilibriums can be used to estimate SP values (SP = log xs/x1, xs and x1 denoting the modifier mole fractions in the stationary and mobile phases, respectively which are in a linear dependence with the log k values. The described procedure includes the determination of the approximate phase equilibrium constant K. By analysis of the Everett equation it was found that in the field of x1/K there are regions of linear dependence of the SP parameter or log k values and the mole fraction of modifiers or its logarithm. Consequently, only in these regions it is possible for two different chromatographic systems to have the same solvent strength scale: x1 or log x1.

  18. Modelling the surface free energy parameters of polyurethane coats-part 1. Solvent-based coats obtained from linear polyurethane elastomers.

    Science.gov (United States)

    Król, Piotr; Lechowicz, Jaromir B; Król, Bożena

    2013-04-01

    Polyurethane elastomers coating were synthesised by using typical diisocyanates, polyether and polyester polyols and HO-tertiary amines or diols as a chain extenders. Mole fractions of structural fragments (κexp) responsible for the polar interactions within polyurethane chains were calculated by (1)H NMR method. Obtained results were confronted with the analogous parameter values (κtheor) calculated on the basis of process stoichiometry, considering the stage of the production of isocyanate prepolymers and reaction of their extension for polyurethanes. Trials of linear correlation between the κexp parameters and surface free energy (SFE) values of investigated coatings were presented. SFE values were determined by Owens-Wendt method, using contact angles measured with the goniometric method. Based on achieved results, another empirical models, allowing for prediction the influence of the kind of polyurethane raw materials on SFE values of received coatings were determined. It was found that it is possible to regulate the SFE in the range millijoules per cubic metre by the selection of appropriate substrates. It has been found that use of 2,2,3,3-tetrafluoro-1,4-butanediol as a fluorinated extender of prepolymer chains is essential to obtain coatings with increased hydrophobicity, applied among others as biomaterials-next to diphenylmethane diisocyanate and polyoxyethylene glycol.

  19. Computation of energy interaction parameters as well as electric dipole intensity parameters for the absorption spectral study of the interaction of Pr(III) with L-phenylalanine, L-glycine, L-alanine and L-aspartic acid in the presence and absence of Ca 2+ in organic solvents

    Science.gov (United States)

    Moaienla, T.; Singh, Th. David; Singh, N. Rajmuhon; Devi, M. Indira

    2009-10-01

    Studying the absorption difference and comparative absorption spectra of the interaction of Pr(III) and Nd(III) with L-phenylalanine, L-glycine, L-alanine and L-aspartic acid in the presence and absence of Ca 2+ in organic solvents, various energy interaction parameters like Slater-Condon ( FK), Racah ( Ek), Lande factor ( ξ4f), nephelauxetic ratio ( β), bonding ( b1/2), percentage-covalency ( δ) have been evaluated applying partial and multiple regression analysis. The values of oscillator strength ( P) and Judd-Ofelt electric dipole intensity parameter Tλ ( λ = 2, 4, 6) for different 4f-4f transitions have been computed. On analysis of the variation of the various energy interaction parameters as well as the changes in the oscillator strength ( P) and Tλ values reveal the mode of binding with different ligands.

  20. Optimization of process parameters of extraction of amentoflavone, quercetin and ginkgetin from Taxus chinensis using supercritical CO2 plus co-solvent.

    Science.gov (United States)

    Ruan, Xiao; Yan, Liu-Ye; Li, Xian-Xian; Liu, Ben; Zhang, Huan; Wang, Qiang

    2014-10-31

    The effects of extraction time, temperature, pressure and different concentration of ethanol and their interactions on the yields of amentoflavone, quercetin and ginkgetin extracted from Taxus chinensis by supercritical CO2 were investigated by using a central composite design (CCD). An CCD experimental design with four factors and five levels was used to optimize the extraction parameters. Ultra performance liquid chromatography (UPLC) was used to analyze the content of the tree components in the extracts. Experimental results show that the main effects of factors and their interactions are significant on the yields (p extraction conditions were established for the three compounds: yield of 4.47 mg/g for amentoflavone at 48 °C, 25 MPa, 2.02 h and 78.5% ethanol, 3.73 mg/g for quercetin at 46 °C, 24 MPa, 2.3 h, 82% ethanol and 3.47 mg/g for ginkgetin at 48 °C, 20 MPa, 2.38 h, 82% ethanol, respectively.

  1. Supercritical-Multiple-Solvent Extraction From Coal

    Science.gov (United States)

    Corcoran, W.; Fong, W.; Pichaichanarong, P.; Chan, P.; Lawson, D.

    1983-01-01

    Large and small molecules dissolve different constituents. Experimental apparatus used to test supercritical extraction of hydrogen rich compounds from coal in various organic solvents. In decreasing order of importance, relevant process parameters were found to be temperature, solvent type, pressure, and residence time.

  2. Molecular Thermodynamic Modeling of Mixed Solvent Solubility

    DEFF Research Database (Denmark)

    Ellegaard, Martin Dela; Abildskov, Jens; O’Connell, John P.

    2010-01-01

    A method based on statistical mechanical fluctuation solution theory for composition derivatives of activity coefficients is employed for estimating dilute solubilities of 11 solid pharmaceutical solutes in nearly 70 mixed aqueous and nonaqueous solvent systems. The solvent mixtures range from...... nearly ideal to strongly nonideal. The database covers a temperature range from 293 to 323 K. Comparisons with available data and other existing solubility methods show that the method successfully describes a variety of observed mixed solvent solubility behaviors using solute−solvent parameters from...

  3. Miscellaneous hydrocarbon solvents.

    Science.gov (United States)

    Bebarta, Vikhyat; DeWitt, Christopher

    2004-08-01

    The solvents discussed in this article are common solvents not categorized as halogenated, aromatic, or botanical. The solvents discussed are categorized into two groups: hydrocarbon mixtures and single agents. The hydrocarbon mixtures discussed are Stoddard solvent, naphtha, and kerosene. The remaining solvents described are n-hexane, methyl n-butyl ketone, dimethylformamide, dimethyl sulfoxide, and butyl mercaptans. Effects common to this group of agents and their unique effects are characterized. Treatment of exposures and toxic effects of these solvents is described, and physiochemical properties and occupational exposure levels are listed.

  4. Parameters Affecting Solvent Production by Clostridium pasteurianum

    OpenAIRE

    Dabrock, Birgit; Bahl, Hubert; Gottschalk, Gerhard

    1992-01-01

    The effect of pH, growth rate, phosphate and iron limitation, carbon monoxide, and carbon source on product formation by Clostridium pasteurianum was determined. Under phosphate limitation, glucose was fermented almost exclusively to acetate and butyrate independently of the pH and growth rate. Iron limitation caused lactate production (38 mol/100 mol) from glucose in batch and continuous culture. At 15% (vol/vol) carbon monoxide in the atmosphere, glucose was fermented to ethanol (24 mol/100...

  5. Solvent resistant nanofiltration membranes

    OpenAIRE

    Dutczak, S.M.

    2011-01-01

    This thesis describes preparation and characterization of membranes for organic solvent filtration (OSF). The main aim was developing membranes for solvent resistant nanofiltration (SRNF) with molecular weight cut-off below 500 g mol-1.

  6. Relationship between Fermi Resonance and Solvent Effects

    Institute of Scientific and Technical Information of China (English)

    JIANG Xiu-Lan; LI Dong-Fei; SUN Cheng-Lin; LI Zhan-Long; YANG Guang; ZHOU Mi; LI Zuo-Wei; GAO Shu-Qin

    2011-01-01

    We theoretically and experimentally study the relationship between Fermi resonance and solvent effects and investigate the Fermi resonance of p-benzoquinone and cyclopentanone in different solvents and the Fermi resonance of CS2 in C6H6 at different concentrations. Also, we investigate the Fermi resonance of C6H6 and CCl4 in their solution at different pressures. It is found that solvent effects can be utilized to search Fermi resonance parameters such as coupling coefficient and spectral intensity ratio, etc., on the other hand, the mechanism of solvent effects can be revealed according to Fermi resonance at high pressure.%@@ We theoretically and experimentally study the relationship between Fermi resonance and solvent effects and investigate the Fermi resonance of p-benzoquinone and cyclopentanone in different solvents and the Fermi resonance of CS2 in C6H6 at different concentrations.Also,we investigate the Fermi resonance of C6H6 and CCl4 in their solution at different pressures.It is found that solvent effects can be utilized to search Fermi resonance parameters such as coupling coefficient and spectral intensity ratio,etc.,on the other hand,the mechanism of solvent effects can be revealed according to Fermi resonance at high pressure.

  7. Solvent abuse: a review.

    Science.gov (United States)

    Barnes, G E

    1979-01-01

    The literature on solvent abuse is reviewed. Methods of use, symptoms of use, and effects of long-term solvent abuse are discussed. Several surveys on solvent use are summarized. The highest prevalence of solvent abuse seems to occur in native peoples undergoing periods of cultural change. Environmental conditions which are postulated as leading to psychological vulnerability and solvent abuse include: low social assets, parental drug use, peer and sibling influence, and acculturative stress. Solvent abuse seems to provide a pharmacological way out of a stressful environment for people who feel helpless to improve their situation in other ways. Methods of intervention that have been proposed for dealing with solvent abuse are discussed. Methods of intervention thus far employed generally have not been evaluated in any systematic fashion. Suggestions for future research are provided.

  8. Cellulose Solubility in Ionic Liquid Mixtures: Temperature, Cosolvent, and Antisolvent Effects.

    Science.gov (United States)

    Minnick, David L; Flores, Raul A; DeStefano, Matthew R; Scurto, Aaron M

    2016-08-18

    Select ionic liquids (ILs) dissolve significant quantities of cellulose through disruption and solvation of inter- and intramolecular hydrogen bonds. In this study, thermodynamic solid-liquid equilibrium was measured with microcrystalline cellulose in a model IL, 1-ethyl-3-methylimidazolium diethyl phosphate ([EMIm][DEP]) and mixtures with protic antisolvents and aprotic cosolvents between 40 and 120 °C. The solubility of cellulose in pure [EMIm][DEP] exhibits an asymptotic maximum of approximately 20 mass % above 100 °C. Solubility studies conducted on antisolvent mixtures with [EMIm][DEP] and [BMIm][Cl] indicate that protic solvents, ethanol, methanol, and water, significantly reduce the cellulose capacity of IL mixtures by 38-100% even at small antisolvent loadings (<5 mass %). Alternatively, IL-aprotic cosolvent (dimethyl sulfoxide, dimethylformamide, and 1,3-dimethyl-2-imidazolidinone) mixtures at mass ratios up to 1:1 enhance cellulose dissolution by 20-60% compared to pure [EMIm][DEP] at select temperatures. Interactions between the IL and molecular solvents were investigated by Kamlet-Taft solvatochromic analysis, FTIR, and NMR spectroscopy. The results indicate that preferential solvation of the IL cation and anion by co- and antisolvents impact the ability of IL ions to interact with cellulose thus affecting the cellulose dissolution capacity of IL-solvent mixtures.

  9. Microstructural studies on variation of defect parameters in Zr–Sn alloys and their transition with interchange of solvent and solute in Zr–Ti and Ti–Zr alloy systems by modified Rietveld method and Warren–Averbach method

    Indian Academy of Sciences (India)

    J Ghosh; S K Chattopadhyay; A K Meikap; S K Chatterjee

    2006-08-01

    The effects of deformation and the transition of microstructural defect states with the interchange of solvent and solute in Ti–Zr and Zr–Ti alloys of six different compositions and Zr–Sn alloys in three different compositions have been investigated by X-ray diffraction line profile analysis. The detailed analysis of the X-ray powder diffraction line profiles was interpreted by Fourier line shape analysis using modified Rietveld method and Warren–Averbach method taking silicon as standard. Finally the microstructural parameters such as coherent domain size, microstrains within domains, faulting probability and dislocation density were evaluated from the analysis of X-ray powder diffraction data of Zr base Sn, Ti and Ti base Zr alloys by modified Rietveld powder structure refinement. This analysis confirms that the growth fault, , is totally absent or negligibly present in Zr–Ti, Ti–Zr and Zr–Sn alloy systems, because the growth fault, , has been observed to be either negative or very small for these alloy systems. This analysis also revealed that the deformation fault, , has significant presence in titanium-base zirconium alloy systems but when zirconium content in the matrix goes on increasing beyond 50%, this faulting behaviour suffers a drastic transition and faulting tendency abruptly drops to a level of negligible presence or zero. This tendency has also been observed in Zr–Sn alloys signifying high stacking fault energy. Therefore, Zr and Zr-base alloys having high stacking fault energy can be used as hard alloys in nuclear technology at high temperature.

  10. Modeling of Salt Solubilities in Mixed Solvents

    DEFF Research Database (Denmark)

    Chiavone-Filho, O.; Rasmussen, Peter

    2000-01-01

    A method to correlate and predict salt solubilities in mixed solvents using a UNIQUAC+Debye-Huckel model is developed. The UNIQUAC equation is applied in a form with temperature-dependent parameters. The Debye-Huckel model is extended to mixed solvents by properly evaluating the dielectric...... constants and the liquid densities of the solvent media. To normalize the activity coefficients, the symmetric convention is adopted. Thermochemical properties of the salt are used to estimate the solubility product. It is shown that the proposed procedure can describe with good accuracy a series of salt...

  11. Modeling of Salt Solubilities in Mixed Solvents

    DEFF Research Database (Denmark)

    Chiavone-Filho, O.; Rasmussen, Peter

    2000-01-01

    A method to correlate and predict salt solubilities in mixed solvents using a UNIQUAC+Debye-Huckel model is developed. The UNIQUAC equation is applied in a form with temperature-dependent parameters. The Debye-Huckel model is extended to mixed solvents by properly evaluating the dielectric...... constants and the liquid densities of the solvent media. To normalize the activity coefficients, the symmetric convention is adopted. Thermochemical properties of the salt are used to estimate the solubility product. It is shown that the proposed procedure can describe with good accuracy a series of salt...

  12. Influence of Solvent-Solvent and Solute-Solvent Interaction Properties on Solvent-Mediated Potential

    Institute of Scientific and Technical Information of China (English)

    ZHOU Shi-Qi

    2005-01-01

    A recently proposed universal calculational recipe for solvent-mediated potential is applied to calculate excess potential of mean force between two large Lennard-Jones (LJ) or hard core attractive Yukawa particles immersed in small LJ solvent bath at supercritical state. Comparison between the present prediction with a hypernetted chain approximation adopted for solute-solute correlation at infinitely dilute limit and existing simulation data shows high accuracy for the region with large separation, and qualitative reliability for the solute particle contact region. The calculational simplicity of the present recipe allows for a detailed investigation on the effect of the solute-solvent and solvent-solvent interaction details on the excess potential of mean force. The resultant conclusion is that gathering of solvent particles near a solute particle leads to repulsive excess PMF, while depletion of solvent particles away from the solute particle leads to attractive excess PMF, and minor change of the solvent-solvent interaction range has large influence on the excess PMF.

  13. Method for Predicting Solubilities of Solids in Mixed Solvents

    DEFF Research Database (Denmark)

    Ellegaard, Martin Dela; Abildskov, Jens; O'Connell, J. P.

    2009-01-01

    A method is presented for predicting solubilities of solid solutes in mixed solvents, based on excess Henry's law constants. The basis is statistical mechanical fluctuation solution theory for composition derivatives of solute/solvent infinite dilution activity coefficients. Suitable approximations...... are made for a single parameter characterizing solute/solvent interactions. Comparisons with available data show that the method is successful in describing a variety of observed mixed solvent solubility behavior, including nearly ideal systems with small excess solubilities, systems with solute......-independent excess solubilities, and systems deviating from these simple rules. Successful predictions for new solvent mixtures cat? be made using limited data from other mixtures....

  14. Alternative Green Solvents Project

    Science.gov (United States)

    Maloney, Phillip R.

    2012-01-01

    Necessary for safe and proper functioning of equipment. Mainly halogenated solvents. Tetrachloride, Trichloroethylene (TCE), CFC-113. No longer used due to regulatory/safety concerns. Precision Cleaning at KSC: Small % of total parts. Used for liquid oxygen (LOX) systems. Dual solvent process. Vertrel MCA (decafluoropentane (DFP) and trons-dichloroethylene) HFE-7100. DFP has long term environmental concerns. Project Goals: a) Identify potential replacements. b) 22 wet chemical processes. c) 3 alternative processes. d) Develop test procedures. e) Contamination and cleaning. f) Analysis. g) Use results to recommend alternative processes. Conclusions: a) No alternative matched Vertrel in this study. b) No clear second place solvent. c) Hydrocarbons- easy; Fluorinated greases- difficult. d) Fluorinated component may be needed in replacement solvent. e) Process may need to make up for shortcoming of the solvent. f) Plasma and SCC02 warrant further testing.

  15. Phase separation phenomena in solutions of poly(2,6-dimethyl-1,4-phenylene oxide). IV. Thermodynamic parameters for solutions in a series of homologous solvents: Toluene to hexylbenzene

    NARCIS (Netherlands)

    Koenhen, D.M.; Bakker, A.; Broens, L.; Berg, van den J.W.A.; Smolders, C.A.

    1984-01-01

    Melting-point curves for solutions of poly(2,6-dimethyl-1,4-phenylene oxide) (PPO) in a series of homologous solvents (toluene to n-hexylbenzene) have been obtained from visual and differential scanning calorimetry measurements. The measured melting points were used to calculate thermodynamic intera

  16. Organogel formation rationalized by Hansen solubility parameters.

    Science.gov (United States)

    Raynal, Matthieu; Bouteiller, Laurent

    2011-08-07

    Some organic compounds gelate particular solvents by forming a network of anisotropic fibres. We show that Hansen solubility parameters can be used to predict the range of solvents that are likely to be gelled by any given gelator.

  17. Supercritical solvent coal extraction

    Science.gov (United States)

    Compton, L. E. (Inventor)

    1984-01-01

    Yields of soluble organic extract are increased up to about 50% by the supercritical extraction of particulate coal at a temperature below the polymerization temperature for coal extract fragments (450 C.) and a pressure from 500 psig to 5,000 psig by the conjoint use of a solvent mixture containing a low volatility, high critical temperature coal dissolution catalyst such as phenanthrene and a high volatility, low critical temperature solvent such as toluene.

  18. Cleaning without chlorinated solvents

    Energy Technology Data Exchange (ETDEWEB)

    Thompson, L.M.; Simandl, R.F.

    1994-12-31

    Because of health and environmental concerns, many regulations have been passed in recent years regarding the use of chlorinated solvents. The Oak Ridge Y-12 Plant has had an active program to find alternatives for these solvents used in cleaning applications for the past 7 years. During this time frame, the quantity of solvents purchased has been reduced by 92%. The program has been a twofold effort. Vapor degreasers used in batch cleaning-operations have been replaced by ultrasonic cleaning with aqueous detergent, and other organic solvents have been identified for use in hand-wiping or specialty operations. In order to qualify these alternatives for use, experimentation was conducted on cleaning ability as well as effects on subsequent operations such as welding, painting and bonding. Cleaning ability was determined using techniques such as X-ray photoelectron spectroscopy (XPS) and Fourier Transform Infrared Spectroscopy (FTIR) which are capable of examining monolayer levels of contamination on a surface. Solvents have been identified for removal of rust preventative oils, lapping oils, machining coolants, lubricants, greases, and mold releases. Solvents have also been evaluated for cleaning urethane foam spray guns, swelling of urethanes and swelling of epoxies.

  19. Solvent selection methodology for pharmaceutical processes: Solvent swap

    DEFF Research Database (Denmark)

    Papadakis, Emmanouil; Kumar Tula, Anjan; Gani, Rafiqul

    2016-01-01

    A method for the selection of appropriate solvents for the solvent swap task in pharmaceutical processes has been developed. This solvent swap method is based on the solvent selection method of Gani et al. (2006) and considers additional selection criteria such as boiling point difference, volati...

  20. Purex process solvent: literature review

    Energy Technology Data Exchange (ETDEWEB)

    Geier, R.G.

    1979-10-01

    This document summarizes the data on Purex process solvent presently published in a variety of sources. Extracts from these various sources are presented herein and contain the work done, the salient results obtained, and the original, unaltered conclusions of the author of each paper. Three major areas are addressed: solvent stability, solvent quality testing, and solvent treatment processes. 34 references, 44 tables.

  1. Halogenated solvent remediation

    Science.gov (United States)

    Sorenson, Kent S.

    2004-08-31

    Methods for enhancing bioremediation of ground water contaminated with nonaqueous halogenated solvents are disclosed. A preferred method includes adding a composition to the ground water wherein the composition is an electron donor for microbe-mediated reductive dehalogenation of the halogenated solvents and enhances mass transfer of the halogenated solvents from residual source areas into the aqueous phase of the ground water. Illustrative compositions effective in these methods include surfactants such as C.sub.2 -C.sub.4 carboxylic acids and hydroxy acids, salts thereof, esters of C.sub.2 -C.sub.4 carboxylic acids and hydroxy acids, and mixtures thereof. Especially preferred compositions for use in these methods include lactic acid, salts of lactic acid, such as sodium lactate, lactate esters, and mixtures thereof. The microbes are either indigenous to the ground water, or such microbes can be added to the ground water in addition to the composition.

  2. Safe battery solvents

    Science.gov (United States)

    Harrup, Mason K.; Delmastro, Joseph R.; Stewart, Frederick F.; Luther, Thomas A.

    2007-10-23

    An ion transporting solvent maintains very low vapor pressure, contains flame retarding elements, and is nontoxic. The solvent in combination with common battery electrolyte salts can be used to replace the current carbonate electrolyte solution, creating a safer battery. It can also be used in combination with polymer gels or solid polymer electrolytes to produce polymer batteries with enhanced conductivity characteristics. The solvents may comprise a class of cyclic and acyclic low molecular weight phosphazenes compounds, comprising repeating phosphorus and nitrogen units forming a core backbone and ion-carrying pendent groups bound to the phosphorus. In preferred embodiments, the cyclic phosphazene comprises at least 3 phosphorus and nitrogen units, and the pendent groups are polyethers, polythioethers, polyether/polythioethers or any combination thereof, and/or other groups preferably comprising other atoms from Group 6B of the periodic table of elements.

  3. Organic solvent topical report

    Energy Technology Data Exchange (ETDEWEB)

    COWLEY, W.L.

    1999-05-13

    This report provides the basis for closing the organic solvent safety issue. Sufficient information is presented to conclude that risk posed by an organic solvent fire is within risk evaluation guidelines. This report updates information contained in Analysis of Consequences of Postulated Solvent Fires in Hanford Site Waste Tanks. WHC-SD-WM-CN-032. Rev. 0A (Cowley et al. 1996). However, this document will not replace Cowley et al (1996) as the primary reference for the Basis for Interim Operation (BIO) until the recently submitted BIO amendment (Hanson 1999) is approved by the US Department of Energy. This conclusion depends on the use of controls for preventing vehicle fuel fires and for limiting the use of flame cutting in areas where hot metal can fall on the waste surface.The required controls are given in the Tank Waste Remediation System Technical Safety Requirements (Noorani 1997b). This is a significant change from the conclusions presented in Revision 0 of this report. Revision 0 of this calcnote concluded that some organic solvent fire scenarios exceeded risk evaluation guidelines, even with controls imposed.

  4. Organic solvent topical report

    Energy Technology Data Exchange (ETDEWEB)

    Cowley, W.L.

    1998-04-30

    This report is the technical basis for the accident and consequence analyses used in the Hanford Tank Farms Basis for Interim Operation. The report also contains the scientific and engineering information and reference material needed to understand the organic solvent safety issue. This report includes comments received from the Chemical Reactions Subcommittee of the Tank Advisory Panel.

  5. Grafting of cellulose acetate with ionic liquids for biofuel purification by a membrane process: Influence of the cation.

    Science.gov (United States)

    Hassan Hassan Abdellatif, Faten; Babin, Jérôme; Arnal-Herault, Carole; David, Laurent; Jonquieres, Anne

    2016-08-20

    A new strategy was developed for grafting ionic liquids (ILs) onto cellulose acetate in order to avoid IL extraction and improve its performance for ethyl tert-butyl ether (ETBE) biofuel purification by the pervaporation membrane process. This work extended the scope of IL-containing membranes to the challenging separation of organic liquid mixtures, in which these ILs were soluble. The ILs contained the same bromide anion and different cations with increasing polar feature. The membrane properties were strongly improved by IL grafting. Their analysis in terms of structure-property relationships revealed the influence of the IL content, chemical structure and chemical physical parameters α, β, π* in the Kamlet-Taft polarity scale. The ammonium IL led to the best normalized flux of 0.182kg/m(2)h for a reference thickness of 5μm, a permeate ethanol content of 100% and an outstanding infinite separation factor for the azeotropic mixture EtOH/ETBE at 50°C.

  6. UV-Vis spectroscopic study and DFT calculation on the solvent effect of trimethoprim in neat solvents and aqueous mixtures.

    Science.gov (United States)

    Almandoz, M C; Sancho, M I; Duchowicz, P R; Blanco, S E

    2014-08-14

    The solvatochromic behavior of trimethoprim (TMP) was analyzed using UV-Vis spectroscopy and DFT methods in neat and binary aqueous solvent mixtures. The effects of solvent dipolarity/polarizability and solvent-solute hydrogen bonding interactions on the absorption maxima were evaluated by means of the linear solvation energy relationship concept of Kamlet and Taft. This analysis indicated that both interactions play an important role in the position of the absorption maxima in neat solvents. The simulated absorption spectra of TMP and TMP:(solvent)n complexes in ACN and H2O using TD-DFT methods were in agreement with the experimental ones. Binary aqueous mixtures containing as co-solvents DMSO, ACN and EtOH were studied. Preferential solvation was detected as a nonideal behavior of the wavenumber curve respective to the analytical mole fraction of co-solvent in all binary systems. TMP molecules were preferentially solvated by the organic solvent over the whole composition range. Index of preferential solvation, as well as the influence of solvent parameters were calculated as a function of solvent composition.

  7. Solvent effect in implicit/explicit model on FT-IR, 1H, 13C and 19F NMR, UV-vis and fluorescence spectra, linear, second- and third-nonlinear optical parameters of 2-(trifluoromethyl)benzoic acid: Experimental and computational study

    Science.gov (United States)

    Avcı, Davut; Altürk, Sümeyye; Tamer, Ömer; Kuşbazoğlu, Mustafa; Atalay, Yusuf

    2017-09-01

    FT-IR, 1H, 13C and 19F NMR, UV-vis and fluorescence spectra for 2-(trifluoromethyl)benzoic acid (2-TFMBA) were recorded. DFT//B3LYP/6-31++G(d,p) calculations were used to determine the optimized molecular geometry, vibrational frequencies, 1H, 13C and 19F GIAO-NMR chemical shifts of 2-TFMBA. The detailed assignments of vibrational frequencies were carried out on the basis of potential energy distribution (PED) by using VEDA program. TD-DFT/B3LYP/6-31++G(d,p) calculations with the PCM (polarizable continuum model) in ethanol and DMSO solvents based on implicit/explicit model and gas phase in the excited state were employed to investigate UV-vis absorption and fluorescence emission wavelengths. The UV-vis and emission spectra were given in ethanol and DMSO solvents, and the major contributions to the electronic transitions were obtained. In addition, the NLO parameters (β, γ and χ(3)) and frontier molecular orbital energies of 2-TFMBA were calculated by using B3LYP/6-31++G(d,p) level. The NLO parameters of 2-TFMBA were compared with that of para-Nitroaniline (pNA) and urea which are the typical NLO materials. The refractive index (n) is calculated by using the Lorentz-Lorenz equation to observe polarization behavior of 2-TFMBA in DMSO and ethanol solvents. In order to investigate intramolecular and hydrogen bonding interactions, NBO calculations were also performed by the same level. To sum up, considering the well-known biological role, photochemical properties of 2-TFMBA were discussed.

  8. Effect of Solvents on Microalbuminuria Among Automobile Painters

    Directory of Open Access Journals (Sweden)

    T Shushtarizadeh

    2008-06-01

    SPSS 11.5.Results: Several studies showed that solvents cause renal disorder (tubular and glomerular, although glomerulonephritis is more prevalent. The mean age of the solvent group was 28.6 ±2.7 years and was 33.7 ±7 years in control group (p<0.05. The mean duration of solvent exposure was 4.8 ±1.5 years. Statistically meaningful differences were found between solvent and control groups for microalbuminuria, increased serum BUN and creatinine levels (p<0.05, although there was no significant correlation between these parameters and the duration of exposure (p>0.05.Conclusion: The results suggest that kidney dysfunction results from chronic occupational exposure to solvents at levels found in automobile painting rooms in Iran. We recommend increased monitoring of workers using solvents and increased review and enforcement of safety regulations regarding such use of solvents.

  9. Solvent Immersion Imprint Lithography

    Energy Technology Data Exchange (ETDEWEB)

    Vasdekis, Andreas E.; Wilkins, Michael J.; Grate, Jay W.; Kelly, Ryan T.; Konopka, Allan; Xantheas, Sotiris S.; Chang, M. T.

    2014-06-21

    The mechanism of polymer disolution was explored for polymer microsystem prototyping, including microfluidics and optofluidics. Polymer films are immersed in a solvent, imprinted and finally brought into contact with a non-modified surface to permanently bond. The underlying polymer-solvent interactions were experimentally and theoretically investigated, and enabled rapid polymer microsystem prototyping. During imprinting, small molecule integration in the molded surfaces was feasible, a principle applied to oxygen sensing. Polystyrene (PS) was employed for microbiological studies at extreme environmental conditions. The thermophile anaerobe Clostridium Thermocellum was grown in PS pore-scale micromodels, revealing a double mean generation lifetime than under ideal culture conditions. Microsystem prototyping through directed polymer dissolution is simple and accessible, while simultaneous patterning, bonding, and surface/volume functionalization are possible in less than one minute.

  10. Diamex solvent regeneration studies

    Energy Technology Data Exchange (ETDEWEB)

    Nicol, C.; Cames, B.; Margot, L.; Ramain, L. [CEA/VALRHO - site de Marcoule, Dept. de Recherche en Retraitement et en Vitrification, DRRV, 30 - Marcoule (France)

    2000-07-01

    The CEA has undertaken the development of the DIAMEX process as the first step in the strategy aiming at recovering minor actinides which could then be transmuted or separately conditioned. The scientific feasibility of this process was demonstrated during counter current hot tests operated in 1993. Then experimental works were conducted, on one hand to optimise the extractant formula, on the other hand to improve the flowsheet. Reference extractant and flowsheet were then chosen, respectively in 1995 and 1996. The next step, still in progress, is the demonstration of the DIAMEX technical feasibility (in 2002); this means that the flowsheet should include solvent regeneration treatments. In this aim, degradation studies were performed to quantify main degradation products, and identify those which could be disturbing in the process. This paper deals with experimental studies performed with intend to propose a regeneration treatment, included in the flowsheet, so that the solvent could be recycled. It comprises: - Quantification of the main degradation products issued from radiolysis or hydrolysis, which are methyl octyl amine (MOA) and carboxylic acids; - Effects of these products on extracting and hydrodynamics performances of the process; - Study of methods able to remove mainly disturbing degradation products. Acidic scrubbing, which are performed in the scrubbing and stripping sections of the DIAMEX process, should allow the quantitative removal of methyl octyl amine. Then basic scrubbings, which were more especially studied, should eliminate at least 80% of carboxylic acids, and part of the cations remaining in the solvent. (authors)

  11. Electrospinning of Grooved Polystyrene Fibers: Effect of Solvent Systems

    Science.gov (United States)

    Liu, Wanjun; Huang, Chen; Jin, Xiangyu

    2015-05-01

    Secondary surface texture is of great significance to morphological variety and further expands the application areas of electrospun nanofibers. This paper presents the possibility of directly electrospinning grooved polystyrene (PS) fibers using both single and binary solvent systems. Solvents were classified as low boiling point solvent (LBPS): dichloromethane (DCM), acetone (ACE), and tetrahydrofuran (THF); high boiling point solvent (HBPS): N, N-dimethylformamide (DMF) and cyclohexanone (CYCo); and non-solvent (NS): 1-butanol (BuOH). By the systematic selection and combination of these solvents at given parameters, we found that single solvent systems produced non-grooved fibers. LBPS/DMF solvent systems resulted in fibers with different grooved textures, while LBPS/CYCo led to fibers with double grooved texture. Grooved fibers can also be fabricated from LBPS/LBPS, NS/LBPS, and NS/HBPS systems under specific conditions. The results indicated that the difference of evaporation rate (DER) between the two solvents played a key role in the formation of grooved texture. The formation of this unique texture should be attributed to three separate mechanisms, namely void-based elongation, wrinkle-based elongation, and collapsed jet-based elongation. Our findings can serve as guidelines for the preparation of ultrafine fibers with grooved secondary texture.

  12. Predicting the Solution Morphology of a Sulfonated Pentablock Copolymer in an Arbitrary Solvent Mixture

    Science.gov (United States)

    Ford, Jamie; Kyei-Manu, William; Winey, Karen

    2013-03-01

    Block copolymers self assemble into a wide array of morphologies in solvents. To predict the solution morphology of the polymer, we assess the interactions between the individual blocks and the solvent or solvents. Here, we use the Hansen solubility parameters to calculate the interactions between a library of solvents and an ABCBA pentablock copolymer with non-polar A and B blocks and a polar, sulfonated C block to predict the expected morphology for a given solvent and compare it to our small-angle X-ray scattering data. In non-polar solvents, we observe micelles with a C core and an A-B corona. We observe inverted micelles in polar solvents - an A-B core with a C corona. We extended our methodology to mixed polar/non-polar solvent systems to predict the solvent ratios corresponding to the transition from micelles to inverted micelles.

  13. Quantitation of buried contamination by use of solvents. Part 1: Solvent degradation of amine cured epoxy resins

    Science.gov (United States)

    Rheineck, A. E.; Heskin, R. A.; Hill, L. W.

    1972-01-01

    The solubility and/or swelling of cured epoxy resins was studied using the solubility parameter method. Determination of solubility parameters were found in order to select solvents for solvent-assisted degradation of cured epoxy polymers used in spacecraft. A method for improving recovery of seeded spores is suggested for assay of buried contaminants. Three commercial epoxy resins were cured using four different alkyl amines. For each resin-amine combination, three levels of amine were used, corresponding to 1/3, 2/3, and all of the amine required to react with the oxirane groups of the resin. The solubility parameters of the 36 resulting model compounds were determined in poorly and moderately hydrogen-bonded solvents. No strongly hydrogen-bonded solvents caused dissolution or swelling. The tolerance of cured resins is discussed in terms of polymer structure.

  14. Occupational solvent exposure and cognition

    Science.gov (United States)

    Sabbath, E.L.; Glymour, M.M.; Berr, C.; Singh-Manoux, A.; Zins, M.; Goldberg, M.

    2012-01-01

    Objective: Chronic occupational solvent exposure is associated with long-term cognitive deficits. Cognitive reserve may protect solvent-exposed workers from cognitive impairment. We tested whether the association between chronic solvent exposure and cognition varied by educational attainment, a proxy for cognitive reserve. Methods: Data were drawn from a prospective cohort of French national gas and electricity (GAZEL) employees (n = 4,134). Lifetime exposure to 4 solvent types (chlorinated solvents, petroleum solvents, benzene, and nonbenzene aromatic solvents) was assessed using a validated job-exposure matrix. Education was dichotomized at less than secondary school or below. Cognitive impairment was defined as scoring below the 25th percentile on the Digit Symbol Substitution Test at mean age 59 (SD 2.8; 88% of participants were retired at testing). Log-binomial regression was used to model risk ratios (RRs) for poor cognition as predicted by solvent exposure, stratified by education and adjusted for sociodemographic and behavioral factors. Results: Solvent exposure rates were higher among less-educated patients. Within this group, there was a dose-response relationship between lifetime exposure to each solvent type and RR for poor cognition (e.g., for high exposure to benzene, RR = 1.24, 95% confidence interval 1.09–1.41), with significant linear trends (p < 0.05) in 3 out of 4 solvent types. Recency of solvent exposure also predicted worse cognition among less-educated patients. Among those with secondary education or higher, there was no significant or near-significant relationship between any quantification of solvent exposure and cognition. Conclusions: Solvent exposure is associated with poor cognition only among less-educated individuals. Higher cognitive reserve in the more-educated group may explain this finding. PMID:22641403

  15. Green Solvents for Precision Cleaning

    Science.gov (United States)

    Grandelli, Heather; Maloney, Phillip; DeVor, Robert; Surma, Jan; Hintze, Paul

    2013-01-01

    Aerospace machinery used in liquid oxygen (LOX) fuel systems must be precision cleaned to achieve a very low level of non-volatile residue (< 1 mg0.1 m2), especially flammable residue. Traditionally chlorofluorocarbons (CFCs) have been used in the precision cleaning of LOX systems, specifically CFC 113 (C2Cl3F3). CFCs have been known to cause the depletion of ozone and in 1987, were banned by the Montreal Protocol due to health, safety and environmental concerns. This has now led to the development of new processes in the precision cleaning of aerospace components. An ideal solvent-replacement is non-flammable, environmentally benign, non-corrosive, inexpensive, effective and evaporates completely, leaving no residue. Highlighted is a green precision cleaning process, which is contaminant removal using supercritical carbon dioxide as the environmentally benign solvent. In this process, the contaminant is dissolved in carbon dioxide, and the parts are recovered at the end of the cleaning process completely dry and ready for use. Typical contaminants of aerospace components include hydrocarbon greases, hydraulic fluids, silicone fluids and greases, fluorocarbon fluids and greases and fingerprint oil. Metallic aerospace components range from small nuts and bolts to much larger parts, such as butterfly valves 18 in diameter. A fluorinated grease, Krytox, is investigated as a model contaminant in these preliminary studies, and aluminum coupons are employed as a model aerospace component. Preliminary studies are presented in which the experimental parameters are optimized for removal of Krytox from aluminum coupons in a stirred-batch process. The experimental conditions investigated are temperature, pressure, exposure time and impeller speed. Temperatures of 308 - 423 K, pressures in the range of 8.3 - 41.4 MPa, exposure times between 5 - 60 min and impeller speeds of 0 - 1000 rpm were investigated. Preliminary results showed up to 86 cleaning efficiency with the

  16. Solvent effects in chemistry

    CERN Document Server

    Buncel, Erwin

    2015-01-01

    This book introduces the concepts, theory and experimental knowledge concerning solvent effects on the rate and equilibrium of chemical reactions of all kinds.  It begins with basic thermodynamics and kinetics, building on this foundation to demonstrate how a more detailed understanding of these effects may be used to aid in determination of reaction mechanisms, and to aid in planning syntheses. Consideration is given to theoretical calculations (quantum chemistry, molecular dynamics, etc.), to statistical methods (chemometrics), and to modern day concerns such as ""green"" chemistry, where ut

  17. Prediction of crystal morphology of cyclotrimethylene trinitramine in the solvent medium by computer simulation: a case of cyclohexanone solvent.

    Science.gov (United States)

    Chen, Gang; Xia, Mingzhu; Lei, Wu; Wang, Fengyun; Gong, Xuedong

    2014-12-11

    The crystal morphology of the energetic material cyclotrimethylene trinitramine (also known as RDX) influenced by the solvent effect was investigated via molecular dynamics simulation. The modified attachment energy (MAE) model was established by incorporating the growth parameter-solvent term. The adsorption interface models were used to study the adsorption interactions between solvent and RDX surfaces. The RDX crystal morphology grown from the cyclohexanone (CYC) solvent as a case investigation was calculated by the MAE model. The calculation results indicated that, due to the effect of CYC solvent, (210) and (111) faces had the greatest morphological importance on the final RDX crystal, while the morphological importance of (020), (002), and (200) faces were reduced. The predicted RDX morphology was in reasonable agreement with the observed experiment result.

  18. Expanding solvent SAGD in heavy oil reservoirs

    Energy Technology Data Exchange (ETDEWEB)

    Govind, P.A. [Society of Petroleum Engineers, Canadian Section, Calgary, AB (Canada)]|[ConocoPhillips Canada Resources Corp., Calgary, AB (Canada); Das, S.; Wheeler, T.J. [Society of Petroleum Engineers, Richardson, TX (United States)]|[ConocoPhillips Co., Houston, TX (United States); Srinivasan, S. [Society of Petroleum Engineers, Richardson, TX (United States)]|[Texas Univ., Austin, TX (United States)

    2008-10-15

    Steam assisted gravity drainage (SAGD) projects have proven effective for the recovery of oil and bitumen. Expanding solvent (ES) SAGD pilot projects have also demonstrated positive results of improved performance. This paper presented the results of a simulation study that investigated several important factors of the ES-SAGD process, including solvent types; concentration; operating pressure; and injection strategy. The objectives of the study were to examine the effectiveness of the ES-SAGD process in terms of production acceleration and energy requirements; to optimize solvent selection; to understand the effect of dilation in unconsolidated oil sands and the directional impact on reservoir parameters and oil production rate in ES-SAGD; and to understand the impact of operating conditions such as pressure, solvent concentration, circulation preheating period and the role of conduction heating and grid size in this process. The advantages of ES-SAGD over SAGD were also outlined. The paper presented results of sensitivity studies that were conducted on these four factors. Conclusions and recommendations for operating strategy were also offered. It was concluded that dilation is an important factor for SAGD performance at high operating pressure. 8 refs., 15 figs.

  19. Effects of solubility properties of solvents and biomass on biomass pretreatment.

    Science.gov (United States)

    Weerachanchai, Piyarat; Kwak, Sang Kyu; Lee, Jong-Min

    2014-10-01

    Hildebrand solubility parameters of biomasses and pretreatment solvents were examined by a method of intrinsic viscosity. This is to be used as basic information in selecting a suitable solvent for biomass pretreatment processes. The effects of mixing1-ethyl-3-methylimidazolium acetate (EMIM-AC) and different solvents, lignin content in a pretreatment solvent, and biomass type on the Hildebrand solubility parameter and thermodynamic properties were carried out and calculated in this work. The Hildebrand solubility parameters of the mixtures are according to those of organic solvents: δH[EMIM-AC/DMA]=25.07biomass compositions (microcrystalline cellulose, xylan and alkali lignin) and biomasses (cassava pulp residue and rice straw) vary in the ranges of 25.14-26.13. The increases of lignin content in the pretreatment solvents lead to the Hildebrand solubility parameter becoming closer to that of lignin.

  20. Calculation and Comparison of Energy Interaction and Intensity Parameters for the Interaction of Nd(III with DL-Valine, DL-Alanine and β-Alanine in Presence and Absence of Ca2+/Zn2+ in Aqueous and Different Aquated Organic Solvents Using 4f-4f Transition Spectra as Probe

    Directory of Open Access Journals (Sweden)

    H. Debecca Devi

    2009-01-01

    Full Text Available Absorption difference and comparative absorption spectrophotometric studies involving 4f-4f transitions of Nd(III and different amino acids: DL-valine, DL-alanine, and β-alanine in presence and absence of Ca(II and Zn(II in aqueous and different aquated organic solvents have been carried out. Variations in the spectral energy parameters: Slater-Condon (FK factor, Racah (EK, Lande factor (ξ4f, nephelauxetic ratio (β, bonding (b1/2, percentage covalency (δ are calculated to explore the mode of interaction of Nd(III with different amino acids: DL-valine, DL-alanine, and β-alanine. The values of experimentally calculated oscillator strength (P and computed values of Judd-Ofelt electric dipole intensity parameters, Tλ (λ = 2,4,6, are also determined for different 4f-4f transitions. The variation in the values of P and Tλ parameters explicitly shows the relative sensitivities of the 4f-4f transitions as well as the specific correlation between relative intensities, ligand structures, and nature of Nd(III-ligand interaction.

  1. Kinetics and Thermodynamics of Oil Extraction from Jatropha curcas L. Using Ethanol as a Solvent

    OpenAIRE

    Silmara Bispo dos Santos; Marcio Arêdes Martins; Ana Lívia Caneschi; Paulo Rafael Morette Aguilar; Jane Sélia dos Reis Coimbra

    2015-01-01

    In the study the yield and kinetic and thermodynamic parameters of the oil extraction process from Jatropha curcas L. using ethanol as a solvent were evaluated for different temperatures, moisture contents of the solid phase, and particle sizes. The extraction process yield increased with contact time of solid particles with the solvent until reaching equilibrium (saturation of the solvent), for all the temperatures, moisture contents, and average particle sizes. These parameters significantl...

  2. Rheological Predictions of Network Systems Swollen with Entangled Solvent

    Science.gov (United States)

    2014-04-01

    solvent was previously studied experimentally. In this article, we use the discrete slip-link model to predict its linear and nonlinear rheology ...Model parameters are obtained from the dynamic modulus data of pure solvent. Network rheology predictions also require an estimate of the fraction and...Triangle Park, NC 27709-2211 rheology ;polymer properties;gels, networks;mathematical modeling;multiscale modeling REPORT DOCUMENTATION PAGE 11. SPONSOR

  3. Phase Behavior of Mixtures of Ionic Liquids and Organic Solvents

    DEFF Research Database (Denmark)

    Abildskov, Jens; Ellegaard, Martin Dela; O’Connell, J.P.

    2010-01-01

    A corresponding-states form of the generalized van der Waals equation, previously developed for mixtures of an ionic liquid and a supercritical solute, is here extended to mixtures including an ionic liquid and a solvent (water or organic). Group contributions to characteristic parameters...... solvents. Here we show results for heavier and more-than-sparingly solutes such as carbon dioxide and propane in ionic liquids....

  4. Spectroscopic and DFT study of solvent effects on the electronic absorption spectra of sulfamethoxazole in neat and binary solvent mixtures.

    Science.gov (United States)

    Almandoz, M C; Sancho, M I; Blanco, S E

    2014-01-24

    The solvatochromic behavior of sulfamethoxazole (SMX) was investigated using UV-vis spectroscopy and DFT methods in neat and binary solvent mixtures. The spectral shifts of this solute were correlated with the Kamlet and Taft parameters (α, β and π(*)). Multiple lineal regression analysis indicates that both specific hydrogen-bond interaction and non specific dipolar interaction play an important role in the position of the absorption maxima in neat solvents. The simulated absorption spectra using TD-DFT methods were in good agreement with the experimental ones. Binary mixtures consist of cyclohexane (Cy)-ethanol (EtOH), acetonitrile (ACN)-dimethylsulfoxide (DMSO), ACN-dimethylformamide (DMF), and aqueous mixtures containing as co-solvents DMSO, ACN, EtOH and MeOH. Index of preferential solvation was calculated as a function of solvent composition and non-ideal characteristics are observed in all binary mixtures. In ACN-DMSO and ACN-DMF mixtures, the results show that the solvents with higher polarity and hydrogen bond donor ability interact preferentially with the solute. In binary mixtures containing water, the SMX molecules are solvated by the organic co-solvent (DMSO or EtOH) over the whole composition range. Synergistic effect is observed in the case of ACN-H2O and MeOH-H2O, indicating that at certain concentrations solvents interact to form association complexes, which should be more polar than the individual solvents of the mixture.

  5. Judd–Ofelt parameters of diglycolamide-functionalized calix[4]arene Eu{sup 3+} complexes in room temperature ionic liquid for structural analysis: Effects of solvents and ligand stereochemistry

    Energy Technology Data Exchange (ETDEWEB)

    Sengupta, Arijit [Bhabha Atomic Research Centre, Trombay, Mumbai 400085 (India); Godbole, Shrikant V. [Bhabha Atomic Research Centre, Trombay, Mumbai 400085 (India); Laboratory of Molecular Nanofabrication, MESA Institute for Nanotechnology, University of Twente, P. O. Box 217, 7500 AE Enschede (Netherlands); Mohapatra, Prasanta K., E-mail: mpatra64@gmail.com [Bhabha Atomic Research Centre, Trombay, Mumbai 400085 (India); Iqbal, Mudassir; Huskens, Jurriaan; Verboom, Willem [Laboratory of Molecular Nanofabrication, MESA Institute for Nanotechnology, University of Twente, P. O. Box 217, 7500 AE Enschede (Netherlands)

    2014-04-15

    The complexation behavior of several diglycolamide (DGA)-functionalized calix [4]arene ligands (C4DGA) with Eu{sup 3+} in C{sub 8}mimNTf{sub 2} (1-octyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide) was studied by time resolved laser fluorescence spectroscopy (TRLFS). The high intensity emission peaks of Eu{sup 3+} at 614 and 619 nm, which are due to the {sup 5}D{sub 0}→{sup 7}F{sub 2} transition, sensitive to the local environment around Eu{sup 3+}, suggest that Eu{sup 3+} sits in a highly asymmetric environment. The metal-ligand stoichiometry of the complexes is 1:1, while there was no inner sphere water molecule around Eu{sup 3+}. The splitting pattern of the individual transitions of Eu{sup 3+} indicates that the local site symmetry around Eu{sup 3+} is C{sub 4V}. Though the emission characteristics of the complexes in C{sub 8}mimNTf{sub 2} and a 1:5 acetonitrile-water mixture were similar, the smaller linewidth in C{sub 8}mimNTf{sub 2} can be attributed to the restricted motion of the Eu{sup 3+} complex. Judd and Ofelt parameters (Ω{sub 2}, Ω{sub 4}) were calculated for all Eu{sup 3+}–C4DGA complexes. Steric crowding around the ligating sites decreases the proximity of Eu{sup 3+} with the carbonyl oxygens. This is evident from a decrease in the Ω{sub 2} value, which is a signature of the increase in the bond length and concomitant decrease in the covalent interactions. Higher transition probabilities (A{sub md}, A{sub 2ed}, A{sub 4ed}) of the Eu{sup 3+}–C4DGA complexes in C{sub 8}mim·NTf{sub 2} compared to a 1:5 acetonitrile-water mixture point to more mixing of the metal f orbitals with the ligand orbitals. The transition probability of the electric-dipole transition of {sup 5}D{sub 0}→{sup 7}F{sub 2} is three times more than the magnetic-dipole transition probability and twice that of the electric-dipole transition of {sup 5}D{sub 0}→{sup 7}F{sub 4}. Alkyl substituents on the amidic nitrogen atoms increase the quantum efficiency as it

  6. SOLVENT EXTRACTION OF URANIUM VALUES

    Science.gov (United States)

    Feder, H.M.; Ader, M.; Ross, L.E.

    1959-02-01

    A process is presented for extracting uranium salt from aqueous acidic solutions by organic solvent extraction. It consists in contacting the uranium bearing solution with a water immiscible dialkylacetamide having at least 8 carbon atoms in the molecule. Mentioned as a preferred extractant is dibutylacetamide. The organic solvent is usually used with a diluent such as kerosene or CCl/sub 4/.

  7. Supercritical multicomponent solvent coal extraction

    Science.gov (United States)

    Corcoran, W. H.; Fong, W. S.; Pichaichanarong, P.; Chan, P. C. F.; Lawson, D. D. (Inventor)

    1983-01-01

    The yield of organic extract from the supercritical extraction of coal with larger diameter organic solvents such as toluene is increased by use of a minor amount of from 0.1 to 10% by weight of a second solvent such as methanol having a molecular diameter significantly smaller than the average pore diameter of the coal.

  8. Selection and design of solvents

    DEFF Research Database (Denmark)

    Gani, Rafiqul

    . With increasing interest on issues such as waste, sustainability, environmental impact and green chemistry, the selection and design of solvents have become important problems that need to be addressed during chemical product-process design and development. Systematic methods and tools suitable for selection......Solvents are liquid solutions consisting of one or more chemicals. They have a very wide use and their use is not necessarily restricted to the process industries. This lecture will discuss the different roles and uses of solvents in chemical products and processes that manufacture them...... and design of solvents will be presented together with application examples. The selection problem is defined as finding known chemicals that match the desired functions of a solvent for a specified set of applications. The design problem is defined as finding the molecular structure (or mixture of molecules...

  9. Solvent degradation products in nuclear fuel processing solvents

    Energy Technology Data Exchange (ETDEWEB)

    Shook, H.E. Jr.

    1988-06-01

    The Savannah River Plant uses a modified Purex process to recover enriched uranium and separate fission products. This process uses 7.5% tri-n-butyl phosphate (TBP) dissolved in normal paraffin hydrocarbons for the solvent extraction of a nitric acid solution containing the materials to be separated. Periodic problems in product decontamination result from solvent degradation. A study to improve process efficiency has identified certain solvent degradation products and suggested mitigation measures. Undecanoic acid, lauric acid, and tridecanoic acid were tentatively identified as diluent degradation products in recycle solvent. These long-chain organic acids affect phase separation and lead to low decontamination factors. Solid phase extraction (SPE) was used to concentrate the organic acids in solvent prior to analysis by high performance liquid chromatography (HPLC). SPE and HPLC methods were optimized in this work for analysis of decanoic acid, undecanoic acid, and lauric acid in solvent. Accelerated solvent degradation studies with 7.5% TBP in normal paraffin hydrocarbons showed that long-chain organic acids and long-chain alkyl butyl phosphoric acids are formed by reactions with nitric acid. Degradation of both tributyl phosphate and hydrocarbon can be minimized with purified normal paraffin replacing the standard grade presently used. 12 refs., 1 fig., 3 tabs.

  10. Maximum solid solubility of transition metals in vanadium solvent

    Institute of Scientific and Technical Information of China (English)

    ZHANG Jin-long; FANG Shou-shi; ZHOU Zi-qiang; LIN Gen-wen; GE Jian-sheng; FENG Feng

    2005-01-01

    Maximum solid solubility (Cmax) of different transition metals in metal solvent can be described by a semi-empirical equation using function Zf that contains electronegativity difference, atomic diameter and electron concentration. The relation between Cmax and these parameters of transition metals in vanadium solvent was studied.It is shown that the relation of Cmax and function Zf can be expressed as ln Cmax = Zf = 7. 316 5-2. 780 5 (△X)2 -71. 278δ2 -0. 855 56n2/3. The factor of atomic size parameter has the largest effect on the Cmax of the V binary alloy;followed by the factor of electronegativity difference; the electrons concentration has the smallest effect among the three bond parameters. Function Zf is used for predicting the unknown Cmax of the transition metals in vanadium solvent. The results are compared with Darken-Gurry theorem, which can be deduced by the obtained function Zf in this work.

  11. Switchable Polarity Solvents: Are They Green?

    Science.gov (United States)

    Plaumann, Heinz

    2017-03-01

    Solvents play an incredibly important role in large scale chemical reactions. Switchable polarity solvents may prove to be a class of solvent that offers energy and material efficiencies greater than existing solvents. This paper examines such solvents and their potential in a variety of chemical reactions.

  12. Universal iso-density polarizable continuum model for molecular solvents

    CERN Document Server

    Gunceler, Deniz

    2014-01-01

    Implicit electron-density solvation models based on joint density-functional theory offer a computationally efficient solution to the problem of calculating thermodynamic quantities of solvated systems from first-principles quantum mechanics. However, despite much recent interest in such models, to date the applicability of such models to non-aqueous solvents has been limited because the determination of the model parameters requires fitting to a large database of experimental solvation energies for each new solvent considered. This work presents an alternate approach which allows development of new solvation models for a large class of protic and aprotic solvents from only simple, single-molecule ab initio calculations and readily available bulk thermodynamic data. We find that this model is accurate to nearly 1.7 kcal/mol even for solvents outside our development set.

  13. Handbook of organic solvent properties

    CERN Document Server

    Smallwood, Ian

    2012-01-01

    The properties of 72 of the most commonly used solvents are given, tabulated in the most convenient way, making this book a joy for industrial chemists to use as a desk reference. The properties covered are those which answer the basic questions of: Will it do the job? Will it harm the user? Will it pollute the air? Is it easy to handle? Will it pollute the water? Can it be recovered or incinerated? These are all factors that need to be considered at the early stages of choosing a solvent for a new product or process.A collection of the physical properties of most commonly used solvents, their

  14. The Solvent Selection framework: solvents for organic synthesis, separation processes and ionic-organic synthesis

    DEFF Research Database (Denmark)

    Mitrofanov, Igor; Sansonetti, Sascha; Abildskov, Jens

    2012-01-01

    problems are presented: 1) solvent selection and design for organic synthesis, 2) solvent screening and design of solvent mixtures for pharmaceutical applications and 3) ionic liquids selection and design as solvents. The application of the framework is highlighted successfully through case studies...... focusing on solvent replacement problem in organic synthesis and solvent mixture design for ibuprofen respectively....

  15. Practical Approaches to Green Solvents

    National Research Council Canada - National Science Library

    Joseph M. DeSimone

    2002-01-01

    Solvents are widely used in commercial manufacturing and service industries. Despite abundant precaution, they inevitably contaminate our air, land, and water because they are difficult to contain and recycle...

  16. Hansen Cleaning Solvent Research Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Environmental regulation will force current baseline  precision cleaning solvent (AK-225) to be phased out starting 2015. We plan to develop  a new...

  17. Applied biotransformations in green solvents.

    Science.gov (United States)

    Hernáiz, María J; Alcántara, Andrés R; García, José I; Sinisterra, José V

    2010-08-16

    The definite interest in implementing sustainable industrial technologies has impelled the use of biocatalysts (enzymes or cells), leading to high chemo-, regio- and stereoselectivities under mild conditions. As usual substrates are not soluble in water, the employ of organic solvents is mandatory. We will focus on different attempts to combine the valuable properties of green solvents with the advantages of using biocatalysts for developing cleaner synthetic processes.

  18. Solvent/Non-Solvent Sintering To Make Microsphere Scaffolds

    Science.gov (United States)

    Laurencin, Cato T.; Brown, Justin L.; Nair, Lakshmi

    2011-01-01

    A solvent/non-solvent sintering technique has been devised for joining polymeric microspheres to make porous matrices for use as drug-delivery devices or scaffolds that could be seeded with cells for growing tissues. Unlike traditional sintering at elevated temperature and pressure, this technique is practiced at room temperature and pressure and, therefore, does not cause thermal degradation of any drug, protein, or other biochemical with which the microspheres might be loaded to impart properties desired in a specific application. Also, properties of scaffolds made by this technique are more reproducible than are properties of comparable scaffolds made by traditional sintering. The technique involves the use of two miscible organic liquids: one that is and one that is not a solvent for the affected polymer. The polymeric microspheres are placed in a mold having the size and shape of the desired scaffold, then the solvent/non-solvent mixture is poured into the mold to fill the void volume between the microspheres, then the liquid mixture is allowed to evaporate. Some of the properties of the resulting scaffold can be tailored through choice of the proportions of the liquids and the diameter of the microspheres.

  19. Extended Hansen solubility approach: naphthalene in individual solvents.

    Science.gov (United States)

    Martin, A; Wu, P L; Adjei, A; Beerbower, A; Prausnitz, J M

    1981-11-01

    A multiple regression method using Hansen partial solubility parameters, delta D, delta p, and delta H, was used to reproduce the solubilities of naphthalene in pure polar and nonpolar solvents and to predict its solubility in untested solvents. The method, called the extended Hansen approach, was compared with the extended Hildebrand solubility approach and the universal-functional-group-activity-coefficient (UNIFAC) method. The Hildebrand regular solution theory was also used to calculate naphthalene solubility. Naphthalene, an aromatic molecule having no side chains or functional groups, is "well-behaved', i.e., its solubility in active solvents known to interact with drug molecules is fairly regular. Because of its simplicity, naphthalene is a suitable solute with which to initiate the difficult study of solubility phenomena. The three methods tested (Hildebrand regular solution theory was introduced only for comparison of solubilities in regular solution) yielded similar results, reproducing naphthalene solubilities within approximately 30% of literature values. In some cases, however, the error was considerably greater. The UNIFAC calculation is superior in that it requires only the solute's heat of fusion, the melting point, and a knowledge of chemical structures of solute and solvent. The extended Hansen and extended Hildebrand methods need experimental solubility data on which to carry out regression analysis. The extended Hansen approach was the method of second choice because of its adaptability to solutes and solvents from various classes. Sample calculations are included to illustrate methods of predicting solubilities in untested solvents at various temperatures. The UNIFAC method was successful in this regard.

  20. Solvent-free extraction of food and natural products

    OpenAIRE

    Fabiano-Tixier, Anne-Sylvie; Vian, Maryline; Allaf, Tamara; Vorobiev, Eugene

    2015-01-01

    This review presents useful and green techniques of solvent-free extraction used in ancient times, such as extraction of olive oil and citrus essential oil, and innovative techniques, such as pulsed electric field, microwave, instantaneous controlled pressure drop, and extrusion. We discuss the devices, their applications, mechanisms, and parameters influencing sample preparation prior to analysis of natural products.

  1. Solvent Effects on Rates and Equilibria: A Practical Approach.

    Science.gov (United States)

    Buncel, Erwin; Wilson, Harold

    1980-01-01

    Described is the transfer function approach which can be applied to a system by measuring the appropriate activation parameters. This approach is conceptually simple and has many mechanistic applications, among which are solvent and structural effects on rates and equilibrium. (Author/DS)

  2. SOLVENT QUALITY AND SOLUTION BEHAVIOR OF NYLON 12

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    The refractive index increment,dynamic and static laser light scattering,intrinsic viscosity [η] and Huggins constant (KH) of nylon 12 have been measured in m-cresol and sulphuric acid/water system at 10-60 ℃.The intrinsic Vicosity,RH,Rg,A2,and (2)1/2 (calculated from vicosity data) and "a" values of nylon 12 are found to be higher in m-cresol than in sulphuric acid.All these parameters decrease with the increase in water contents in sulphuric acid.The refractive index increment,KH and activation energy show an opposite trend to that of [η].The intrinsic viscosity,RH,Rg,A2,20℃.It has been concluded that the variation in size,interaction parameter(second virial coefficient).[η] and KH of the polymer solutions with the alteration in solvent composition and temperature are the out come of change in thermodynamic quality of solvents,selective adsorption,hydrogen bonding and conformational transitions.It has also been concluded that the increase in temperature first enhances the quality of the solvent,encourages hydrogen bonding and specific adsorption,and then deteriorates.bringing conformational transitions in the polymer molecules.However,the addition of water to sulphuric acid continuously deteriorates the solvent quality.This characteristic of the solvent system brings conformational changes in the polymer especially at low temperatures.

  3. Handbook of green chemistry, green solvents, supercritical solvents

    CERN Document Server

    Anastas, Paul T; Jessop, Philip G

    2014-01-01

    Green Chemistry is a vitally important subject area in a world where being as green and environmentally sound as possible is no longer a luxury but a necessity. Its applications include the design of chemical products and processes that help to reduce or eliminate the use and generation of hazardous substances. The Handbook of Green Chemistry comprises 12 volumes, split into subject-specific sets as follows: Set I: Green Catalysis Set II: Green Solvents Volume 4: Supercritical Solvents Volume 5: Reactions in Water Volume 6: Ionic Liquids

  4. DOE solvent handbook information sheet

    Energy Technology Data Exchange (ETDEWEB)

    Chavez, A.A.

    1992-01-01

    Solvents and cleaners are used in the Department of Defense (DOD) and the Department of Energy-Defense Program (DOE-DP) maintenance facilities for removing wax, grease, oil, carbon, machining fluids, solder fluxes, mold releases, and other contaminants before repairing or electroplating parts. Private industry also uses cleaners and degreasers for surface preparation of various metals. Growing environmental and worker safety concerns have brought attention to these solvents and cleaners, most of which are classified as toxic. Tightening government regulations have already excluded the use of some chemicals, and restrict the use of various halogenated hydrocarbons because of their atmospheric-ozone depleting effects, as well as their cancer-related risks. As a result, a program was established to develop an efficient, easily accessible, electronic solvent utilization handbook. This is being accomplished by: (1) identifying solvents (alternatives) that are not currently restricted by government regulations for use DOE-DP facilities, and private industry, (2) evaluating their cleaning performance, (3) evaluating their corrosivity, (4) evaluating their air emissions, (5) evaluating the possibility of recycling or recovering all or portions of the alternative degreasers, (6) testing substitute solvents compatibility with non-metallic materials, (7) inputting all of the data gathered (including previous biodegradability information) into a database, and (8) developing a methodology for efficient, widespread access to the data base information system.

  5. DOE solvent handbook information sheet

    Energy Technology Data Exchange (ETDEWEB)

    Chavez, A.A.

    1992-05-01

    Solvents and cleaners are used in the Department of Defense (DOD) and the Department of Energy-Defense Program (DOE-DP) maintenance facilities for removing wax, grease, oil, carbon, machining fluids, solder fluxes, mold releases, and other contaminants before repairing or electroplating parts. Private industry also uses cleaners and degreasers for surface preparation of various metals. Growing environmental and worker safety concerns have brought attention to these solvents and cleaners, most of which are classified as toxic. Tightening government regulations have already excluded the use of some chemicals, and restrict the use of various halogenated hydrocarbons because of their atmospheric-ozone depleting effects, as well as their cancer-related risks. As a result, a program was established to develop an efficient, easily accessible, electronic solvent utilization handbook. This is being accomplished by: (1) identifying solvents (alternatives) that are not currently restricted by government regulations for use DOE-DP facilities, and private industry, (2) evaluating their cleaning performance, (3) evaluating their corrosivity, (4) evaluating their air emissions, (5) evaluating the possibility of recycling or recovering all or portions of the alternative degreasers, (6) testing substitute solvents compatibility with non-metallic materials, (7) inputting all of the data gathered (including previous biodegradability information) into a database, and (8) developing a methodology for efficient, widespread access to the data base information system.

  6. Computer Aided Solvent Selection and Design Framework

    DEFF Research Database (Denmark)

    Mitrofanov, Igor; Conte, Elisa; Abildskov, Jens

    , millions of tons solvents have to be wasted every year [2]. Therefore, it becomes important to minimize and optimize the use of organic solvents as much as possible, to satisfy the “Green Chemistry Principles” [3]. Another challenge is that currently solvent selection relies very much on previous...... is to develop a systematic framework and implement it as software for selection and design of solvents for many applications including organic synthesis, complex reaction systems and solvent-based separations. The solvent selection framework is based on a combination of knowledge from industrial practice...... identification of solvent candidates using special software ProCAMD and ProPred, which are the implementations of computer-aided molecular techniques. The second consists of assigning the RS-indices following the reaction–solvent and then consulting the known solvent database and identifying the set of solvents...

  7. Solvent effects on C=O stretching frequencies of some 1-substituted 2-pyrrolidinones

    NARCIS (Netherlands)

    Engberts, J.B.F.N.; Famini, G.R.; Perjéssy, A.; Wilson, L.Y.

    1998-01-01

    In an effort to model solute–solvent interactions, the C=O stretching frequencies of five 1-substituted 2-pyrrolidinones and four other carbonyl-containing compounds were measured for 30 common solvents. These were then correlated with four empirical parameter sets and one theoretical

  8. Solvent effects on C=O stretching frequencies of some 1-substituted 2-pyrrolidinones

    NARCIS (Netherlands)

    Engberts, J.B.F.N.; Famini, G.R.; Perjéssy, A.; Wilson, L.Y.

    1998-01-01

    In an effort to model solute–solvent interactions, the C=O stretching frequencies of five 1-substituted 2-pyrrolidinones and four other carbonyl-containing compounds were measured for 30 common solvents. These were then correlated with four empirical parameter sets and one theoretical (computational

  9. Glycerol based solvents: synthesis, properties and applications

    OpenAIRE

    García, José I.; García-Marín, Héctor; Pires, Elísabet

    2014-01-01

    The most recent advances in the use of glycerol and glycerol derivatives as solvents are reviewed. There are an increasing number of examples of the use of glycerol itself as a reaction medium, solvent-reagent or a dispersive medium for a large variety of applications. In the case of glycerol derivatives, new synthetic methods, physico-chemical properties and application examples as solvents are revised. Recent studies in the field of solvent classification, as well as solvent substitution is...

  10. Multiple sclerosis and organic solvents

    DEFF Research Database (Denmark)

    Mortensen, J T; Brønnum-Hansen, Henrik; Rasmussen, K

    1998-01-01

    We investigated a possible causal relation between exposure to organic solvents in Danish workers (housepainters, typographers/printers, carpenters/cabinetmakers) and onset of multiple sclerosis. Data on men included in the Danish Multiple Sclerosis Register (3,241 men) were linked with data from......, and butchers. Over a follow-up period of 20 years, we observed no increase in the incidence of multiple sclerosis among men presumed to be exposed to organic solvents. It was not possible to obtain data on potential confounders, and the study design has some potential for selection bias. Nevertheless......, the study does not support existing hypotheses regarding an association between occupational exposure to organic solvents and multiple sclerosis....

  11. Comparison and Combination of Solvent Extraction and Adsorption for Crude Glycerol Enrichment

    OpenAIRE

    Hunsom, Mali; Saila, Payia; Chaiyakam, Penpisuth; Kositnan, Winata

    2016-01-01

    A comparative study of enrichment of crude glycerol via solvent extraction and adsorption was performed at a laboratory scale at ambient temperature (30 oC). Effect of various parameters on the properties of the obtained glycerol including glycerol-, ash- and contaminant contents and color, was explored. The results showed that the enrichment of glycerol by solvent extraction was significantly affected by the solvent type and ratio of solvent to pre-treated crude glycerol. The use of n-C3H7OH...

  12. Solvent substitution: an analysis of comprehensive hazard screening indices.

    Science.gov (United States)

    Debia, M; Bégin, D; Gérin, M

    2011-06-01

    The air index (ψ(i)(air)) of the PARIS II software (Environmental Protection Agency), the Indiana Relative Chemical Hazard Score (IRCHS), and the Final Hazard Score (FHS) used in the P2OASys system (Toxics Use Reduction Institute) are comprehensive hazard screening indices that can be used in solvent substitution. The objective of this study was to evaluate these indices using a list of 67 commonly used or recommended solvents. The indices ψ(i)(air), IRCHS and FHS were calculated considering 9, 13, and 33 parameters, respectively, that summarized health and safety hazards, and environmental impacts. Correlation and sensitivity analyses were performed. The vapor hazard ratio (VHR) was used as a reference point. Two good correlations were found: (1) between VHR and ψ(i)(air) (ρ = 0.84), (2) and between IRCHS and FHS (ρ = 0.81). Values of sensitivity ratios above 0.2 were found with ψ(i)(air) (4 of 9 parameters) and IRCHS (3 of 13 parameters), but not with FHS. Overall, the three indices exhibited important differences in the way they integrate key substitution factors, such as volatility, occupational exposure limit, skin exposure, flammability, carcinogenicity, photochemical oxidation potential, atmospheric global effects, and environmental terrestrial and aquatic effects. These differences can result in different choices of alternatives between indices, including the VHR. IRCHS and FHS are the most comprehensive indices but are very tedious and complex to use and lack sensitivity to several solvent-specific parameters. The index ψ(i)(air) is simpler to calculate but does not cover some parameters important to solvents. There is presently no suitably comprehensive tool available for the substitution of solvents. A two-tier approach for the selection of solvents is recommended to avoid errors that could be made using only a global index or the consideration of the simple VHR. As a first tier, one would eliminate solvent candidates having crucial impacts. As a

  13. Solid-liquid solvent extraction of metal ions

    Institute of Scientific and Technical Information of China (English)

    Bo Peng; Haiyan Fan; Jinzhang Gao

    2003-01-01

    An overview of extraction of some trace metal ions using molten solvent (low melting substance) during last two decadesis presented. The development of this technique since its inception is briefly traced. The comparison of extraction efficiency, thermo-dynamics and kinetics mainly involving extraction of rare earth ions between molten solvent extraction at high temperature and usualliquid-liquid extraction at room temperature are discussed in detail. The various parameters obtained from the previous and presentstudies such as equilibrium extraction constant Kex, pH1/2, thermodynamic and kinetic data are displayed in tabular form. Finally, thecurrent demands, disadvantages and future prospects are also evaluated.

  14. Polar and low polar solvents media effect on dipole moments of some diazo Sudan dyes.

    Science.gov (United States)

    Zakerhamidi, M S; Golghasemi Sorkhabi, Sh; Shamkhali, A N

    2014-06-05

    Absorption and fluorescence spectra of three Sudan dyes (SudanIII, SudanIV and Sudan black B) were recorded in various solvents with different polarity in the range of 300-800nm, at room temperature. The solvatochromic method was used to investigate dipole moments of these dyes in ground and excited states, in different media. The solvatochromic behavior of these substances and their solvent-solute interactions were analyzed via solvent polarity parameters. Obtained results express the effects of solvation on tautomerism and molecular configuration (geometry) of Sudan dyes in solvent media with different polarity. Furthermore, analyze of solvent-solute interactions and value of ground and excited states dipole moments suggests different forms of resonance structures for Sudan dyes in polar and low-polar solvents.

  15. Solvatochromism and linear solvation energy relationship of the kinase inhibitor SKF86002

    Science.gov (United States)

    Khattab, Muhammad; Van Dongen, Madeline; Wang, Feng; Clayton, Andrew H. A.

    2017-01-01

    We studied the spectroscopic characteristics of SKF86002, an anti-inflammatory and tyrosine kinase inhibitor drug candidate. Two conformers SKF86002A and SKF86002B are separated by energy barriers of 19.68 kJ·mol- 1 and 6.65 kJ·mol- 1 due to H-bonds, and produce the three major UV-Vis absorption bands at 325 nm, 260 nm and 210 nm in cyclohexane solutions. This environment-sensitive fluorophore exhibited emission in the 400-500 nm range with a marked response to changes in environment polarity. By using twenty-two solvents for the solvatochromism study, it was noticed that solvent polarity, represented by dielectric constant, was well correlated with the emission wavelength maxima of SKF86002. Thus, the SKF86002 fluorescence peak red shifted in aprotic solvents from 397.5 nm in cyclohexane to 436 nm in DMSO. While the emission maximum in hydrogen donating solvents ranged from 420 nm in t-butanol to 446 nm in N-methylformamide. Employing Lippert-Mataga, Bakhshiev and Kawski models, we found that one linear correlation provided a satisfactory description of polarity effect of 18 solvents on the spectral changes of SKF86002 with R2 values 0.78, 0.80 and 0.80, respectively. Additionally, the multicomponent linear regression analysis of Kamlet-Taft (R2 = 0.94) revealed that solvent acidity, basicity and polarity accounted for 31%, 24% and 45% of solvent effects on SKF86002 emission, respectively. While Catalán correlation (R2 = 0.92) revealed that solvatochromic change of SKF86002 emission was attributed to changes in solvent dipolarity (71%), solvent polarity (12%), solvent acidity (11%) and solvent basicity (6%). Plot of Reichardt transition energies and emission energies of SKF86002 in 18 solvents showed also a linear correlation with R2 = 0.90. The dipole moment difference between excited and ground state was calculated to be 3.4-3.5 debye.

  16. The effect of solvent on the kinetics of the oxidation of benzaldehydes by quinolinium chlorochromate in aqueous organic solvent media

    Directory of Open Access Journals (Sweden)

    G. FATIMA JEYANTHI

    2002-12-01

    Full Text Available The kinetics of the oxidation of benzaldehyde and para-substituted benzaldehydes by quinolinium chlorochromate in water-dimethylformamide mixtures has been studied under pseudo-first-order conditions at 25±0.2°C. The operation of non-specific and specific solvent-solute interactions was explored by correlating the rate data with solvent parameters through a correlation analysis technique. Both electron-releasing and electron-withdrawing substitutents enhance the rate of oxidation and the Hammett plot shows a break in the reactivity order indicating the applicability of a dual mechanism.

  17. Which solvent for olfactory testing?

    Science.gov (United States)

    Philpott, C M; Goodenough, P C; Wolstenholme, C R; Murty, G E

    2004-12-01

    The physical properties of any carrier can deteriorate over time and thus alter the results in any olfactory test. The aim of this study was to evaluate clinically potential solvents as a clean odourless carrier for olfactory testing. Sweet almond oil, pure coconut oil, pure peach kernel oil, dipropylene glycol, monopropylene glycol, mineral oil and silicone oil were studied. The experimentation was conducted in two parts. First, an olfactory device was used to conduct air through the solvents on a weekly basis using a cohort of six volunteers to assess the perceived odour of each solvent at weekly intervals. Secondly a cross-reference test was performed using small bottled solutions of phenylethyl-alcohol and 1-butanol in 10-fold dilutions to compare any perceived difference in concentrations over a period of 8 weeks. We concluded that mineral oil is the most suitable carrier for the purpose of olfactory testing, possessing many desirable characteristics of an olfactory solvent, and that silicone oil may provide a suitable alternative for odorants with which it is miscible.

  18. Conformation of repaglinide: A solvent dependent structure

    Science.gov (United States)

    Chashmniam, Saeed; Tafazzoli, Mohsen

    2017-09-01

    Experimental and theoretical conformational study of repaglinide in chloroform and dimethyl sulfoxide was investigated. By applying potential energy scanning (PES) at B3LYP/6-311++g** and B3LYP-D3/6-311++g** level of theory on rotatable single bonds, four stable conformers (R1-R4) were identified. Spin-spin coupling constant values were obtained from a set of 2D NMR spectra (Hsbnd H COSY, Hsbnd C HMQC and Hsbnd C HMBC) and compared to its calculated values. Interestingly, from 1HNMR and 2D-NOESY NMR, it has been found that repaglinide structure is folded in CDCl3 and cause all single bonds to rotate at an extremely slow rate. On the other hand, in DMSO-d6, with strong solvent-solute intermolecular interactions, the single bonds rotate freely. Also, energy barrier and thermodynamic parameters for chair to chair interconversion was measured (13.04 kcal mol-1) in CDCl3 solvent by using temperature dynamic NMR.

  19. Method for analyzing solvent extracted sponge core

    Energy Technology Data Exchange (ETDEWEB)

    Ellington, W.E.; Calkin, C.L.

    1988-11-22

    For use in solvent extracted sponge core measurements of the oil saturation of earth formations, a method is described for quantifying the volume of oil in the fluids resulting from such extraction. The method consists of: (a) separating the solvent/oil mixture from the water in the extracted fluids, (b) distilling at least a portion of the solvent from the solvent/oil mixture substantially without co-distillation or loss of the light hydrocarbons in the mixture, (c) determining the volume contribution of the solvent remaining in the mixture, and (d) determining the volume of oil removed from the sponge by substracting the determined remaining solvent volume.

  20. Water as a solvent for life

    Science.gov (United States)

    Pohorille, Andrew

    2015-08-01

    “Follow the water” is our basic strategy in searching for life in the universe. The universality of water as the solvent for living systems is usually justified by arguing that water supports the rich organic chemistry that seeds life, but alternative chemistries are possible in other organic solvents. Here, other, essential criteria for life that have not been sufficiently considered so far, will be discussed.Life is based on non-covalent interactions. They might be either specific (enzyme-substrate interactions, selective ion transport) or nonspecific (lipid-lipid or lipid-protein interactions). Their strength needs to be properly tuned, and this is mediated by the solvent. If interactions are too weak, there might be undesired response to natural fluctuations of physical and chemical parameters. If they are too strong it could impede kinetics and energetics of cellular processes. Thus, the solvent must allow for balancing these interactions, which provides strong constraints for life.Water exhibits a remarkable trait that it promotes both solvophobic and solvophilic interactions. Solvophobic (hydrophobic in the case of water) interactions are necessary for self-organization of matter. They are responsible, among others, for the formation of membranes and protein folding. The diversity of structures supported by hydrophobic interactions is the hallmark of terrestrial life responsible for its diversity, evolution and the ability to survive environmental changes. Solvophilic interactions, in turn, are needed to ensure solubility of polar species. Water offers a large temperature domain of stable liquid and the characteristic hydrophobic effects are a consequence of the temperature insensitivity of essential properties of its liquid state. Water, however, might not be the only liquid with these properties. Properties of water and other pure liquids or their mixtures that have a high dielectric constant and simultaneously support self-organization will be

  1. Lipase catalyzed esterification of glycidol in organic solvents.

    Science.gov (United States)

    Martins, J F; Da Ponte, M N; Barreiros, S

    1993-08-05

    We studied the resolution of racemic glycidol through esterification with butyric acid catalyzed by porcine pancreatic lipase in organic media. A screening of seven solvents (log P values between 0.49 and 3.0, P being the n-octanol-water partition coefficient of the solvent) showed that neither log P nor the logarithm of the molar solubility of water in the solvent provides good correlations between enantioselectivity and the properties of the organic media. Chloroform was one of the best solvents as regards the enantiomeric purity (e. p.) of the ester produced. In this solvent, the optimum temperature for the reaction was determined to be 35 degrees C. The enzyme exhibited maximum activity at a water content of 13 +/- 2% (w/w). The enantiomeric purity obtained was 83 +/- 2% of (S)-glycidyl butyrate and did not depend on the alcohol concentration or the enzyme water content for values of these parameters up to 200 mM and 25% (w/w), respectively. The reaction was found to follow a BiBi mechanism.

  2. [Generic method for determination of volatile organic solvents in cosmetics].

    Science.gov (United States)

    Da, Jing; Huang, Xianglu; Wang, Gangli; Cao, Jin; Zhang, Qingsheng

    2014-11-01

    A generic screening, confirmation and determination method was established based on 36 commonly used volatile organic solvents in cosmetics by headspace gas chromatography- mass spectrometry (GC-MS). This method included a database for pilot screening and identifi- cation of those solvents and their quantitative method. Pilot screening database was composed by two sections, one was household section built by two columns with opposite polarities (col- umn VF-1301 ms and DB-5 ms) using retention index in different column systems as qualitative parameter, and the other was NIST MS search version 2.0. Meanwhile, the determination method of the 36 volatile solvents was developed with GC-MS. Cosmetic samples were dissolved in water and transferred to a headspace vial. After 30 min equilibration at 60 °C, the samples were analyzed by GC-MS equipped with a capillary chromatographic column VF-1301 ms. The external calibration was used for quantification. The limits of detection were from 0.01 to 3.3 μg/g, and the recoveries were from 60.77% to 126.6%. This study provided a generic method for pilot screening, identification, and quantitation of volatile organic solvents in cosmetics, and may solve the problem that different analytical methods need to be developed for different targeted compounds and pilot screening for potential candidate solvent residues.

  3. (Co-)solvent selection for single-wall carbon nanotubes: best solvents, acids, superacids and guest-host inclusion complexes.

    Science.gov (United States)

    Torrens, Francisco; Castellano, Gloria

    2011-06-01

    Analysis of 1-octanol-water, cyclohexane-water and chloroform (CHCl(3))-water partition coefficients P(o-ch-cf) allows calculation of molecular lipophilicity patterns, which show that for a given atom log P(o-ch-cf) is sensitive to the presence of functional groups. Program CDHI does not properly differentiate between non-equivalent atoms. The most abundant single-wall carbon nanotube (SWNT), (10,10), presents a relatively small aqueous solubility and large elementary polarizability, P(o-ch-cf) and kinetic stability. The SWNT solubility is studied in various solvents, finding a class of non-hydrogen-bonding Lewis bases with good solubility. Solvents group into three classes. The SWNTs in some organic solvents are cationic while in water/Triton X mixture are anionic. Categorized solubility is semiquantitatively correlated with solvent parameters. The coefficient of term β is positive while the ones of ε and V negative. The electron affinity of d-glucopyranoses (d-Glcp(n)) suggests the formation of colloids of anionic SWNTs in water. Dipole moment for d-Glcp(n)-linear increases with n until four in agreement with 18-fold helix. The I(n)(z-) and SWNT(-) are proposed to form inclusion complexes with cyclodextrin (CD) and amylose (Amy). Starch, d-Glcp, CD and Amy are proposed as SWNT co-solvents. Guests-hosts are unperturbed. A central channel expansion is suggested.

  4. SOLVENT EFFECT ON EXTRACTION OF GALLIC ACID FROM AMALAKI CHURNA (EMBLICA OFFICINALIS Gaertn. TO REDUCE MATRIX EFFECT USING HPTLC AND UV-SPECTROSCOPY WITH 12 DIFFERENT NATURE SOLVENTS

    Directory of Open Access Journals (Sweden)

    Sukla V.J.

    2012-06-01

    Full Text Available Standardization of Ayurvedic formulations is an important aspect for research in Indian medicine. In this era every Pharma company prefer to use pure extract of component for production of best product in short period of time. The literature survey reveals that no work has been reported for solvent selection of extraction of Ayurvedic drugs. Amalaki is one of the most useable ayurveda drug. So, the present study was selected with an aim to select solvent for extraction of component of interest. Standard for evaluating quality of Amalaki churna by employing various physico-chemical parameters. For solvent selection 12 different nature solvents are selected for extraction. Polar solvent selected are Water, Di methylsulfoxide (DMSO, Ethylene glycol, Acetonitrile, Di methyl formeamide (DMF and Methanol. Non polar solvents are Acetone, Acetic acid, Ethyl acetate, Chloroform, Di ethylether and Toluene. Extraction was done by maceration method. Results are taken by chromatographic and spectrophotometric methods. In observation component was easily extracted with less interfering component in non polar solvent. Gallic acid is component of interest for Amalaki and it is well extracted in Di ethyl ether as per result of chromatography and spectroscopy. Conclusion is that selection of solvent for extraction as per their component of interest from material.

  5. Reactions and Separations in Green Solvents

    NARCIS (Netherlands)

    Van Spronsen, J.

    2010-01-01

    Most chemical processes involve solvents in the reaction and the separation step. These solvents give rise to a heavy environmental and economical burden. Moreover, these solvents are based on non-sustainable resources like petroleum. The aim of this thesis has been to develop a number of alternativ

  6. Reactions and Separations in Green Solvents

    NARCIS (Netherlands)

    Van Spronsen, J.

    2010-01-01

    Most chemical processes involve solvents in the reaction and the separation step. These solvents give rise to a heavy environmental and economical burden. Moreover, these solvents are based on non-sustainable resources like petroleum. The aim of this thesis has been to develop a number of

  7. The solvent component of macromolecular crystals

    Energy Technology Data Exchange (ETDEWEB)

    Weichenberger, Christian X. [European Academy of Bozen/Bolzano (EURAC), Viale Druso 1, Bozen/Bolzano, I-39100 Südtirol/Alto Adige (Italy); Afonine, Pavel V. [Lawrence Berkeley National Laboratory (LBNL), 1 Cyclotron Road, Mail Stop 64R0121, Berkeley, CA 94720 (United States); Kantardjieff, Katherine [California State University, San Marcos, CA 92078 (United States); Rupp, Bernhard, E-mail: br@hofkristallamt.org [k.-k. Hofkristallamt, 991 Audrey Place, Vista, CA 92084 (United States); Medical University of Innsbruck, Schöpfstrasse 41, A-6020 Innsbruck (Austria)

    2015-04-30

    On average, the mother liquor or solvent and its constituents occupy about 50% of a macromolecular crystal. Ordered as well as disordered solvent components need to be accurately accounted for in modelling and refinement, often with considerable complexity. The mother liquor from which a biomolecular crystal is grown will contain water, buffer molecules, native ligands and cofactors, crystallization precipitants and additives, various metal ions, and often small-molecule ligands or inhibitors. On average, about half the volume of a biomolecular crystal consists of this mother liquor, whose components form the disordered bulk solvent. Its scattering contributions can be exploited in initial phasing and must be included in crystal structure refinement as a bulk-solvent model. Concomitantly, distinct electron density originating from ordered solvent components must be correctly identified and represented as part of the atomic crystal structure model. Herein, are reviewed (i) probabilistic bulk-solvent content estimates, (ii) the use of bulk-solvent density modification in phase improvement, (iii) bulk-solvent models and refinement of bulk-solvent contributions and (iv) modelling and validation of ordered solvent constituents. A brief summary is provided of current tools for bulk-solvent analysis and refinement, as well as of modelling, refinement and analysis of ordered solvent components, including small-molecule ligands.

  8. The hype with ionic liquids as solvents

    Science.gov (United States)

    Kunz, Werner; Häckl, Katharina

    2016-09-01

    In this mini review, we give our personal opinion about the present state of the art concerning Ionic Liquids, proposed as alternative solvents. In particular, we consider their different drawbacks and disadvantages and discuss the critical aspects of the research of Ionic Liquids as solvents. Finally, we point out some aspects on potentially promising Ionic Liquid solvents.

  9. Phase behavior and second osmotic virial coefficient for competitive polymer solvation in mixed solvent solutions.

    Science.gov (United States)

    Dudowicz, Jacek; Freed, Karl F; Douglas, Jack F

    2015-11-21

    We apply our recently developed generalized Flory-Huggins (FH) type theory for the competitive solvation of polymers by two mixed solvents to explain general trends in the variation of phase boundaries and solvent quality (quantified by the second osmotic virial coefficient B2) with solvent composition. The complexity of the theoretically predicted miscibility patterns for these ternary mixtures arises from the competitive association between the polymer and the solvents and from the interplay of these associative interactions with the weak van der Waals interactions between all components of the mixture. The main focus here lies in determining the influence of the free energy parameters for polymer-solvent association (solvation) and the effective FH interaction parameters {χαβ} (driving phase separation) on the phase boundaries (specifically the spinodals), the second osmotic virial coefficient B2, and the relation between the positions of the spinodal curves and the theta temperatures at which B2 vanishes. Our classification of the predicted miscibility patterns is relevant to numerous applications of ternary polymer solutions in industrial formulations and the use of mixed solvent systems for polymer characterization, such as chromatographic separation where mixed solvents are commonly employed. A favorable comparison of B2 with experimental data for poly(methyl methacrylate)/acetonitrile/methanol (or 1-propanol) solutions only partially supports the validity of our theoretical predictions due to the lack of enough experimental data and the neglect of the self and mutual association of the solvents.

  10. Solvent based hydrogen bonding: impact on poly(3-hexylthiophene) nanoscale morphology and charge transport characteristics.

    Science.gov (United States)

    Chang, Mincheol; Choi, Dalsu; Fu, Boyi; Reichmanis, Elsa

    2013-06-25

    We demonstrate that supramolecular assembly and subsequent enhancement of charge transport characteristics of conjugated polymers can be facilitated simply by adding small amounts of a more volatile poor solvent, which can hydrogen bond with the majority solvent. Addition of up to 2 vol % acetone to a precursor solution of poly(3-hexylthiophene) (P3HT) in chloroform leads to approximately a 4-fold increase in P3HT field-effect mobility. The improvement is associated with hydrogen bonding interactions between acetone and chloroform which decrease the evaporation rate of the mixed solvent. P3HT is less soluble in the binary solvent than in the more readily vaporized chloroform component, and this characteristic enables the supramolecular assembly of P3HT chains at the nanoscale. Two-dimensional molecular ordering of the polymer film was controlled by varying the quantity of poor solvent added to the precursor solution, and the correlation between field-effect mobility and molecular ordering was investigated. Hansen solubility parameters were used to systematically understand how the solvent mixture enhances the alignment and assembly of polymer chains and influences subsequent thin film properties. The value of the relative energy difference (RED) of the solvent with respect to P3HT increased from less than 1 to more than 1 during film formation, which indicates that the solvent characteristics are initially those of a good solvent but transform into those of a poor dissolution medium. A mechanistic illustration of the molecular ordering process during film formation is postulated.

  11. Investigation of solvent annealing time dependence on morphology formation in polystyrene-block-polylactide thin films

    Science.gov (United States)

    Gnabasik, Ryan; Nelson, Gunnar; Baruth, Andrew

    2015-03-01

    Solvent vapor annealing exposes a block polymer film to the vapors of one or more solvents, swelling the film. This process increases polymer mobility and can direct a self-assembly process by tuning the surface energy. Despite its efficacy to produce well-ordered, periodic nanostructures, no standardized production scheme exists. This is primarily due to a lack of understanding the intricate role multiple, incommensurate parameters play. By analogy to thermal annealing of elemental solids, the time a thin film spends in an equilibrium solvent concentration is one factor that will dictate the degree of ordering. To elucidate, optimized annealing conditions for perpendicular cylinder forming polystyrene-block-polylactide exist at solvent concentrations just below the order-disorder transition, where the kinetic and thermal processes required for recrystallization and crystal growth are optimally fast (similar to thermal annealing). By use of a purpose-built, climate-controlled solvent annealing chamber, we map out the annealing time dependence for non-optimized solvent concentrations. Namely, at lower solvent concentrations, where mobility is limited, longer times are required for large lateral correlation lengths. In situ spectral reflectance monitors solvent concentration, regulated viaa mass-flow controlled solvent inlet, offering precision control over annealing. Atomic force microscopy, in conjunction with O2 plasma etching, provides 3-dimensional imaging of the nanoscale morphology. This work was funded by NASA Nebraska Space Grant.

  12. Solvent cleaning system and method for removing contaminants from solvent used in resin recycling

    Science.gov (United States)

    Bohnert, George W.; Hand, Thomas E.; DeLaurentiis, Gary M.

    2009-01-06

    A two step solvent and carbon dioxide based system that produces essentially contaminant-free synthetic resin material and which further includes a solvent cleaning system for periodically removing the contaminants from the solvent so that the solvent can be reused and the contaminants can be collected and safely discarded in an environmentally safe manner.

  13. Substitution of carcinogenic solvent dichloromethane for the extraction of volatile compounds in a fat-free model food system.

    Science.gov (United States)

    Cayot, Nathalie; Lafarge, Céline; Bou-Maroun, Elias; Cayot, Philippe

    2016-07-22

    Dichloromethane is known as a very efficient solvent, but, as other halogenated solvents, is recognized as a hazardous product (CMR substance). The objective of the present work is to propose substitution solvent for the extraction of volatile compounds. The most important physico-chemical parameters in the choice of an appropriate extraction solvent of volatile compounds are reviewed. Various solvents are selected on this basis and on their hazard characteristics. The selected solvents, safer than dichloromethane, are compared using the extraction efficiency of volatile compounds from a model food product able to interact with volatile compounds. Volatile compounds with different hydrophobicity are used. High extraction yields were positively correlated with high boiling points and high Log Kow values of volatile compounds. Mixtures of solvents such as azeotrope propan-2-one/cyclopentane, azeotrope ethyl acetate/ethanol, and mixture ethyl acetate/ethanol (3:1, v/v) gave higher extraction yields than those obtained with dichloromethane.

  14. SOLVENT SENSITIVITY OF THE WAVE-NUMBER CHARACTERIZING THE CARBONYL STRETCHING VIBRATION OF N-CYCLOHEXYL-2-PYRROLIDINONE DISSOLVED IN PURE LIQUIDS AND IN MIXTURES FORMED BY HEXANE AND DEUTERIOTRICHLOROMETHANE AT 298.2-K

    NARCIS (Netherlands)

    ENGBERTS, JBFN; PERJESSY, A; BLANDAMER, MJ

    1993-01-01

    The dependence of nuBAR(C=O) on solvent for N-cyclohexyl-2-pyrrolidinone (NCP) as solute in 18 pure solvents can be described using a two-parameter equation based on the Taft-Kamlet pi* (dipolarity/polarisability) and alpha proton donor parameters. In alcoholic solvents two bands are recorded, the b

  15. Ranking solvent interactions and dielectric constants with [Pt(mesBIAN)(tda)]: A cautionary tale for polarity determinations in ionic liquids.

    Science.gov (United States)

    Baker, Gary A; Rachford, Aaron A; Castellano, Felix N; Baker, Sheila N

    2013-04-02

    The solvatochromic properties of [Pt(mesBIAN)(tda)] are studied in traditional molecular solvents and ionic liquids and duly compared along established empirical solvent parameter scales. The charge-transfer absorption band of [Pt(mesBIAN)(tda)] is determined to be primarily dependent upon solvent acidity and dipolarity. Notably, ionic liquids do not obey the same well-behaved trend as molecular solvents, highlighting the complexity and domain (nano)segregation inherent to ionic liquids.

  16. Properties of polylactide inks for solvent-cast printing of three-dimensional freeform microstructures.

    Science.gov (United States)

    Guo, Shuang-Zhuang; Heuzey, Marie-Claude; Therriault, Daniel

    2014-02-04

    Solvent-cast printing is a highly versatile microfabrication technique that can be used to construct various geometries such as filaments, towers, scaffolds, and freeform circular spirals by the robotic deposition of a polymer solution ink onto a moving stage. In this work, we have performed a comprehensive characterization of the solvent-cast printing process using polylactide (PLA) solutions by analyzing the flow behavior of the solutions, the solvent evaporation kinetics, and the effect of process-related parameters on the crystallization of the extruded filaments. Rotational rheometry at low to moderate shear rates showed a nearly Newtonian behavior of the PLA solutions, while capillary flow analysis based on process-related data indicated shear thinning at high shear rates. Solvent vaporization tests suggested that the internal diffusion of the solvent through the filaments controlled the solvent removal of the extrudates. Different kinds of three-dimensional (3D) structures including a layer-by-layer tower, nine-layer scaffold, and freeform spiral were fabricated, and a processing map was given to show the proper ranges of process-related parameters (i.e., polymer content, applied pressure, nozzle diameter, and robot velocity) for the different geometries. The results of differential scanning calorimetry revealed that slow solvent evaporation could increase the ability of PLA to complete its crystallization process during the filament drying stage. The method developed here offers a new perspective for manufacturing complex structures from polymer solutions and provides guidelines to optimize the various parameters for 3D geometry fabrication.

  17. Effect of solvents on the characteristics of rosin walled microcapsules prepared by a solvent evaporation technique.

    Science.gov (United States)

    Sheorey, D S; Dorle, A K

    1991-01-01

    Rosin microcapsules were prepared by a solvent evaporation technique using solvents with different rates of evaporation. Sulphadiazine was used as a model drug. The microcapsules were studied for their size, drug content, wall thickness, surface characteristics and in vitro release. The mean diameter increased and the drug content decreased as the rate of evaporation of the solvent increased. Fast evaporating solvents produced thick walled microcapsules with innumerable surface pores/cracks compared with slow evaporating solvents.

  18. Modeling Solvent Broadening on the Vibronic Spectra of a Series of Coumarin Dyes. From Implicit to Explicit Solvent Models.

    Science.gov (United States)

    Cerezo, Javier; Avila Ferrer, Francisco J; Prampolini, Giacomo; Santoro, Fabrizio

    2015-12-08

    We present a protocol to estimate the solvent-induced broadening of electronic spectra based on a model that explicitly takes into account the environment embedding the solute. Starting from a classical approximation of the solvent contribution to the spectrum, the broadening arises from the spread of the excitation energies due to the fluctuation of the solvent coordinates, and it is represented as a Gaussian line shape that convolutes the vibronic spectrum of the solute. The latter is computed in harmonic approximation at room temperature with a time-dependent approach. The proposed protocol for the computation of spectral broadening exploits molecular dynamics (MD) simulations performed on the solute-solvent system, keeping the solute degrees of freedom frozen, followed by the computation of the excitation properties with a quantum mechanics/molecular mechanics (QM/MM) approach. The factors that might influence each step of the protocol are analyzed in detail, including the selection of the empirical force field (FF) adopted in the MD simulations and the QM/MM partition of the system to compute the excitation energies. The procedure is applied to a family of coumarin dyes, and the results are compared with experiments and with the predictions of a very recent work (Cerezo et al., Phys. Chem. Chem. Phys. 2015, 17, 11401-11411), where an implicit model was adopted for the solvent. The final spectra of the considered coumarins were obtained without including ad hoc phenomenological parameters and indicate that the broadenings computed with explicit and implicit models both follow the experimental trend, increasing as the polarity change from the initial to the final state increases. More in detail, the implicit model provides larger estimations of the broadening that are closer to the experimental evidence, while explicit models appear to better capture relative differences arising from different solvents or different solutes. Possible inaccuracies of the adopted

  19. Advanced integrated solvent extraction systems

    Energy Technology Data Exchange (ETDEWEB)

    Horwitz, E.P.; Dietz, M.L.; Leonard, R.A. [Argonne National Lab., IL (United States)

    1997-10-01

    Advanced integrated solvent extraction systems are a series of novel solvent extraction (SX) processes that will remove and recover all of the major radioisotopes from acidic-dissolved sludge or other acidic high-level wastes. The major focus of this effort during the last 2 years has been the development of a combined cesium-strontium extraction/recovery process, the Combined CSEX-SREX Process. The Combined CSEX-SREX Process relies on a mixture of a strontium-selective macrocyclic polyether and a novel cesium-selective extractant based on dibenzo 18-crown-6. The process offers several potential advantages over possible alternatives in a chemical processing scheme for high-level waste treatment. First, if the process is applied as the first step in chemical pretreatment, the radiation level for all subsequent processing steps (e.g., transuranic extraction/recovery, or TRUEX) will be significantly reduced. Thus, less costly shielding would be required. The second advantage of the Combined CSEX-SREX Process is that the recovered Cs-Sr fraction is non-transuranic, and therefore will decay to low-level waste after only a few hundred years. Finally, combining individual processes into a single process will reduce the amount of equipment required to pretreat the waste and therefore reduce the size and cost of the waste processing facility. In an ongoing collaboration with Lockheed Martin Idaho Technology Company (LMITCO), the authors have successfully tested various segments of the Advanced Integrated Solvent Extraction Systems. Eichrom Industries, Inc. (Darien, IL) synthesizes and markets the Sr extractant and can supply the Cs extractant on a limited basis. Plans are under way to perform a test of the Combined CSEX-SREX Process with real waste at LMITCO in the near future.

  20. Effect of solvents on the fractionation of high oleic-high stearic sunflower oil.

    Science.gov (United States)

    Bootello, Miguel A; Garcés, Rafael; Martínez-Force, Enrique; Salas, Joaquín J

    2015-04-01

    Solvent fractionation of high oleic-high stearic (HOHS) sunflower oil was studied to determine the best solvent to use (hexane or acetone) in terms of the operational parameters and properties of the final stearins. Acetone fractionation on two types of HOHS sunflower oils (N17 and N20) was carried out at temperatures from 5 to 10 °C using micelles with different oil/solvent ratios. Acetone was more suitable than hexane as a solvent for HSHO sunflower oil fractionation because it allowed the oil to be fractionated at higher temperatures and at lower supercooling degrees. Likewise, a sunflower soft stearin obtained by dry fractionation of HOHS sunflower oil was also used to produce high-melting point stearins by acetone or hexane fractionation. The fractionation of these stearins could be performed at higher temperatures and gave higher yields. The combination of dry and solvent fractionation to obtain tailor-made stearins is discussed.

  1. Correlation between thermal diffusion and solvent self-diffusion in semidilute and concentrated polymer solutions.

    Science.gov (United States)

    Rauch, J; Hartung, M; Privalov, A F; Köhler, W

    2007-06-07

    We have performed measurements of thermal diffusion coefficients DT and solvent self-diffusion coefficients Dss in semidilute to concentrated polymer solutions. Solutes of different glass transition temperatures and solvents of different solvent qualities have been used. The investigated systems are in detail: poly(dimethyl-siloxane) in toluene, tristyrene in toluene, polystyrene in toluene, polystyrene in tetrahydrofuran, polystyrene in benzene, and polystyrene in cyclohexane. The thermal diffusion data are compared to our data and literature data for solvent self-diffusion coefficients. In all systems the concentration dependence of DT closely parallels the one of Dss which may be viewed as a local probe for friction on a length scale of the size of one polymer segment. This identifies local friction as the dominating parameter determining the concentration dependence of DT. Solvent quality, in contrast, has no influence on DT.

  2. Dynamics around solutes and solute-solvent complexes in mixed solvents.

    Science.gov (United States)

    Kwak, Kyungwon; Park, Sungnam; Fayer, M D

    2007-09-04

    Ultrafast 2D-IR vibrational echo experiments, IR pump-probe experiments, and FT-IR spectroscopy of the hydroxyl stretch of phenol-OD in three solvents, CCl4, mesitylene (1, 3, 5 trimethylbenzene), and the mixed solvent of mesitylene and CCl4 (0.83 mole fraction CCl4), are used to study solute-solvent dynamics via observation of spectral diffusion. Phenol forms a complex with Mesitylene. In the mesitylene solution, there is only complexed phenol; in the CCl4 solution, there is only uncomplexed phenol; and in the mixed solvent, both phenol species are present. Dynamics of the free phenol in CCl4 or the mixed solvent are very similar, and dynamics of the complex in mesitylene and in the mixed solvent are very similar. However, there are differences in the slowest time scale dynamics between the pure solvents and the mixed solvents. The mixed solvent produces slower dynamics that are attributed to first solvent shell solvent composition variations. The composition variations require a longer time to randomize than is required in the pure solvents, where only density variations occur. The experimental results and recent MD simulations indicate that the solvent structure around the solute may be different from the mixed solvent's mole fraction.

  3. Application of electron paramagnetic resonance spectroscopy for validation of the novel (AN+DN) solvent polarity scale.

    Science.gov (United States)

    Malavolta, Luciana; Poletti, Erick F; Silva, Elias H; Schreier, Shirley; Nakaie, Clovis R

    2008-06-01

    Based on solvation studies of polymers, the sum (1:1) of the electron acceptor (AN) and electron donor (DN) values of solvents has been proposed as an alternative polarity scale. To test this, the electron paramagnetic resonance isotropic hyperfine splitting constant, a parameter known to be dependent on the polarity/proticity of the medium, was correlated with the (AN+DN) term using three paramagnetic probes. The linear regression coefficient calculated for 15 different solvents was approximately 0.9, quite similar to those of other well-known polarity parameters, attesting to the validity of the (AN+DN) term as a novel "two-parameter" solvent polarity scale.

  4. INFLUENCE OF ORGANIC SOLVENTS ON WATER DISSOCIATION IN BIPOLAR MEMBRANE

    Directory of Open Access Journals (Sweden)

    Sheldeshov N. V.

    2015-12-01

    Full Text Available The article discusses results of experimental research of the influence of aprotic and proton solvents on reaction rate of water molecules dissociation in the bipolar membrane MB-1 by the method of electrochemical impedance frequency spectrum. It was discovered, that addition of organic component in aqueous solutions results in significant influence on the parameters of water dissociation in a bipolar region of the membrane. The reason for this influence is the reduction of the mass fraction of water in solution and, consequently, in a bipolar region of the membrane, which itself reduces the rate of the dissociation reaction. Another reason for the influence of the organic solvent is its effect on the network of hydrogen bonds existing in water and aqueous solutions. Depending on the nature of organic solvent and its concentration, the network of hydrogen bonds may be strengthened, or destroyed, thus facilitating removal of the proton involved in the reactions between water molecules and catalytic centers in cation-exchange and anion-exchange layer of bipolar membrane, or retarding removal of proton. This leads respectively to speed up or slow down the rate of dissociation in the bipolar region of the membrane, as well as changing the constants of the dissociation reaction of water. Introduction of organic solvent in solutions, which are in the contact with bipolar membrane, is a convenient method of investigating the role of solution composition on the rate of proton transfer between water molecules and catalytic centers in the membranes

  5. Solvent-Dependent Pyranopterin Cyclization in Molybdenum Cofactor Model Complexes.

    Science.gov (United States)

    Williams, Benjamin R; Gisewhite, Douglas; Kalinsky, Anna; Esmail, Alisha; Burgmayer, Sharon J Nieter

    2015-09-08

    The conserved pterin dithiolene ligand that coordinates molybdenum (Mo) in the cofactor (Moco) of mononuclear Mo enzymes can exist in both a tricyclic pyranopterin dithiolene form and as a bicyclic pterin-dithiolene form as observed in protein crystal structures of several bacterial molybdoenzymes. Interconversion between the tricyclic and bicyclic forms via pyran scission and cyclization has been hypothesized to play a role in the catalytic mechanism of Moco. Therefore, understanding the interconversion between the tricyclic and bicyclic forms, a type of ring-chain tautomerism, is an important aspect of study to understand its role in catalysis. In this study, equilibrium constants (K(eq)) as well as enthalpy, entropy, and free energy values are obtained for pyran ring tautomerism exhibited by two Moco model complexes, namely, (Et4N)[Tp*Mo(O)(S2BMOPP)] (1) and (Et4N)[Tp*Mo(O)(S2PEOPP)] (2), as a solvent-dependent equilibrium process. Keq values obtained from (1)H NMR data in seven deuterated solvents show a correlation between solvent polarity and tautomer form, where solvents with higher polarity parameters favor the pyran form.

  6. Poly-(3-hexylthiophene) Aggregate Formation in Binary Solvent Mixtures: An Excitonic Coupling Analysis

    Science.gov (United States)

    Boucher, David; Johnson, Calynn

    2014-03-01

    We have studied the aggregation behavior of P3HT [Mn ~ 28.2 kDa, regioregularity >96 %, PDI ~ 1.3] in 96 solvent mixtures is studied using UV-Vis absorption spectroscopy. We used Hansen solubility parameters (HSPs) and Spano excitonic coupling analyses to identify correlations between the properties of the solvent mixtures and the extent of structural order of the aggregates. It is clear that the identity of the poor solvent used to drive aggregation has a significant impact on the excitonic coupling behavior and, hence, the structural order of the P3HT aggregates. However, solubility parameter theory does not account nor provide a predictive theory for the observed trends. Instead, qualitative arguments based on the nature of the interactions between the solvents and the polythiophene and hexyl side chain motifs are used to rationalize the kinetics of formation and the observed excitonic coupling characteristics of the P3HT aggregates.

  7. Solvent Dynamical Effects in Electron Transfer: Electrochemical-Exchange Kinetics of Sesquibicyclic Hydrazines as a Probe of Coupled Vibrational Activation

    Science.gov (United States)

    1992-10-01

    Wisconsin group shows that a significantly better correlation of the solvent-dependent kinetics are obtained with the Kosower Z parameter than with the...log kh1 for 1+/0 self exchange in nine solvents, including three alcohols, correlates linearly with the Kosower Z or the closely related E?(30

  8. Predicting the Solution Morphology of a Sulfonated Block Copolymer in Binary Solvent Mixtures

    Science.gov (United States)

    Griffin, Philip; Salmon, Grace; Ford, Jamie; Winey, Karen

    2015-03-01

    The physicochemical properties of solvent-casted block copolymer films are highly dependent on the microscopic morphology of the solutions from which they are cast. In order to achieve macroscopically homogenous polymer solutions, binary or higher-degree solvent mixtures are often required, which introduces additional complexity in understanding the molecular level interactions that control block copolymer self-assembly in solution. Using small angle x-ray scattering, we have explored the solution morphology in ternary blends of a sulfonated pentablock copolymer in select binary solvent mixtures over a range of solvent compositions and polymer concentrations. We have found that the solution morphologies in these ternary blends depend strongly on the composition of the solvent mixture. Furthermore, we demonstrate that the solvent-composition-dependent morphologies can be accurately predicted by quantifying the polymer/solvent interactions using Hansen solubility parameters. These studies are an important step toward developing a complete and predictive understanding of the solution morphology of complex polymer/solvent mixtures.

  9. Steady state recycling chromatography with solvent removal-effect of solvent removal constraints on process operation under ideal conditions.

    Science.gov (United States)

    Siitonen, Jani; Sainio, Tuomo

    2014-05-09

    Steady state recycling chromatography (SSR) offers a means to reduce eluent consumption and increase productivity in preparative and production scale chromatographic separations. Even better performance is obtained with an integrated process by coupling solvent removal unit to the chromatographic separation unit. Here a design method for SSR with an integrated solvent removal unit (SSR-SR) is presented. The method is more practical than previous work as the effect of physical constraints, such as solubility or viscosity, imposed on the amount of solvent removed is included. The method holds under ideal conditions for binary systems with competitive Langmuir isotherm model. The design equations allow calculation of the regions of feasible operating parameters when either the maximum concentrations in the solvent removal unit or of the solution fed into the chromatographic column is restricted. The method was applied to analyze the performance of different SSR-SR configurations in two case studies: the separation of mandelic acid enantiomers and the separation of EMD 53986 enantiomers. The benefits of SSR-SR are relatively small under ideal conditions but the design method developed here can give a good starting point for designing SSR-SR processes under non-ideal conditions.

  10. PEMFC electrode preparation: Influence of the solvent composition and evaporation rate on the catalytic layer microstructure

    Energy Technology Data Exchange (ETDEWEB)

    Fernandez, R.; Daza, L. [Instituto de Catalisis y Petroleoquimica, CSIC, C/ Marie Curie, 2, 28049 Madrid (Spain); Ferreira-Aparicio, P. [Centro de Investigaciones Energeticas Medioambientales y Tecnologicas (CIEMAT), Avda. Complutense, 22, 28040 Madrid (Spain)

    2005-10-10

    A series of parameters affecting the catalytic layer microstructure in polymer exchange fuel cell electrodes have been evaluated. The deposition of the catalytic layer in the gas diffusion support is shown to depend not only on the ink deposition method but also on the characteristics of the solvent used to disperse both the catalyst and the Nafion ionomer. The solvent viscosity and its dielectric constant are two important factors to control for the catalytic ink preparation. In particular, the solvent dielectric constant is shown to be directly related to the electrode performance in single cell tests. (author)

  11. Is Water a Universal Solvent for Life?

    Science.gov (United States)

    Pohorill, Andrew

    2012-01-01

    There are strong reasons to believe that the laws, principles and constraints of physics and chemistry are universal. It is much less clear how this universality translates into our understanding of the origins of life. Conventionally, discussions of this topic focus on chemistry that must be sufficiently rich to seed life. Although this is clearly a prerequisite for the emergence of living systems, I propose to focus instead on self-organization of matter into functional structures capable of reproduction, evolution and responding to environmental changes. In biology, most essential functions are largely mediated by noncovalent interactions (interactions that do not involve making or breaking chemical bonds). Forming chemical bonds is only a small part of what living systems do. There are specific implications of this point of view for universality. I will concentrate on one of these implications. Strength of non-covalent interactions must be properly tuned. If they were too weak, the system would exhibit undesired, uncontrolled response to natural fluctuations of physical and chemical parameters. If they were too strong kinetics of biological processes would be slow and energetics costly. This balance, however, is not a natural property of complex chemical systems. Instead, it has to be achieved with the aid of an appropriate solvent for life. In particular, potential solvents for life must be characterized by a high dielectric constant to ensure solubility of polar species and sufficient flexibility of biological structures stabilized by electrostatic interactions. Among these solvents, water exhibits a remarkable trait that it also promotes solvophobic (hydrophobic) interactions between non-polar species, typically manifested by a tendency of these species to aggregate and minimize their contacts with the aqueous solvent. Hydrophobic interactions are responsible, at least in part, for many self-organization phenomena in biological systems, such as the formation

  12. Biological Treatment of Solvent-Based Paint

    Science.gov (United States)

    2011-01-01

    solvent. In addition, hydrocarbon mixtures, aromatic hydrocarbon, and Medium Aliphatic Solvent Naphtha are descriptors used by the manufactures to...Enamel Aromatic Hydrocarbon 14 Mineral Spirits 10 Naphtha 10 Ethyl Benzene 0.21 Xylene 1.0 Sherwin Williams Co Enamel Mineral Spirits 49...Solvent Naphtha 31.5 Non-hazardous Ingredients 68 Parker Paints Enamel Mineral Spirits 17 Naphtha 7 Aromatic Hydrocarbons 3 1,2,4

  13. A solvent tolerant isolate of Enterobacter aerogenes.

    Science.gov (United States)

    Gupta, Anshu; Singh, Rajni; Khare, S K; Gupta, M N

    2006-01-01

    A solvent tolerant strain of Enterobacter aerogenes was isolated from soil by cyclohexane enrichment. Presence of cyclohexane (20%) in culture media prolonged the lag phase and caused reduction in biomass. Transmission electron micrographs showed convoluted cell membrane and accumulation of solvent in case of the cells grown in cyclohexane. The Enterobacter isolate was able to grow in the range of organic solvents having log P above 3.2 and also in presence of mercury, thus showing potential for treatment of solvent rich wastes.

  14. Organic solvent use in enterprises in Japan.

    Science.gov (United States)

    Nagasawa, Yasuhiro; Ukai, Hirohiko; Okamoto, Satoru; Samoto, Hajime; Itoh, Kenji; Moriguchi, Jiro; Sakuragi, Sonoko; Ohashi, Fumiko; Takada, Shiro; Kawakami, Tetsuya; Ikeda, Masayuki

    2011-01-01

    This study was initiated to elucidate possible changes in types of organic solvents (to be called solvents in short) used in enterprises in Japan through comparison of current solvent types with historical data since 1983. To investigate current situation in solvent use in enterprises, surveys were conducted during one year of 2009 to 2010. In total, workroom air samples in 1,497 unit workplaces with solvent use were analyzed in accordance with regulatory requirements. Typical use pattern of solvents was as mixtures, accounting for >70% of cases. Adhesives spreading (followed by adhesion) was relatively common in small-scale enterprises, whereas printing and painting work was more common in middle-scale ones, and solvent use for testing and research purpose was basically in large-scaled enterprises. Through-out printing, painting, surface coating and adhesive application, toluene was most common (being detected in 49 to 82% of workplaces depending on work types), whereas isopropyl alcohol was most common (49%) in degreasing, cleaning and wiping workplaces. Other commonly used solvents were methyl alcohol, ethyl acetate and acetone (33 to 37%). Comparison with historical data in Japan and literature-retrieved data outside of Japan all agreed with the observation that toluene is the most commonly used solvent. Application of trichloroethylene and 1,1,1-trichloroethane, once common in 1980s, has ceased to exist in recent years.

  15. Extractive Distillation with Salt in Solvent

    Institute of Scientific and Technical Information of China (English)

    1999-01-01

    Extractive distillation with salt in solvent is a new process for producing anhydrous ethanol by combining the principle of "salt effect" and some traditional extractive distillation methods. Compared with the common extractive distillation the performance of solvent is improved, the recycling amount of solvent is reduced to 1/4-1/5, and the number of theoretical plates is reduced to 1/3. Energy consumption and cost of equipment are also reduced and continuous production is realized. High efficiency and low solvent wastage make this technique feasible.

  16. OCCUPATIONAL SOLVENT EXPOSURE ASSOCIATED WITH DEVELOPMENTAL TOXICITY

    Directory of Open Access Journals (Sweden)

    Alina-Costina LUCA

    2016-05-01

    Full Text Available Organic solvent is a broad term that applies to many classes of chemicals. The solvent (benzene, toluene etc. aspects of occupational exposure are reviewed via the examination of the use, occurrence, and disposition as well as population’s potential of risk. The general public can be exposed to solvent in ambient air as a result of its occurrence in paint process. Solvents are primarily irritants to the skin and mucous membranes and have narcotic properties at high concentrations. Published epidemiological data identified various types of birth defects in certain occupations.

  17. Solubility of C60 and PCBM in Organic Solvents.

    Science.gov (United States)

    Wang, Chun I; Hua, Chi C

    2015-11-12

    The ability to correlate fullerene solubility with experimentally or computationally accessible parameters can significantly facilitate nanotechnology nowadays for a wide range of applications, while providing crucial insight into optimum design of future fullerene species. To date, there has been no single relationship that satisfactorily describes the existing data clearly manifesting the effects of solvent species, system temperature, and isomer. Using atomistic molecular dynamics simulations on two standard fullerene species, C60 and PCBM ([6,6]-phenyl-C61-butyric acid methyl ester), in a representative series of organic solvent media (i.e., chloroform, toluene, chlorobenzene, 1,3-dichlorobenzene, and 1,2-dichlorobenzene), we show that a single time constant characterizing the dynamic stability of a tiny (angstrom-sized) solvation shell encompassing the fullerene particle can be utilized to effectively capture the known trends of fullerene solubility as reported in the literature. The underlying physics differs substantially between the two fullerene species, however. Although C60 was previously shown to be dictated by a diffusion-limited aggregation mechanism, the side-chain-substituted PCBM is demonstrated herein to proceed with an analogous reaction-limited aggregation with the "reaction rate" set by the fullerene rotational diffusivity in the medium. The present results suggest that dynamic quantities-in contrast to the more often employed, static ones-may provide an excellent means to characterize the complex (entropic and enthalpic) interplay between fullerene species and the solvent medium, shed light on the factors determining the solvent quality of a nanoparticle solution, and, in particular, offer a practical pathway to foreseeing optimum fullerene design and fullerene-solvent interactions.

  18. Parameter Estimation

    DEFF Research Database (Denmark)

    2011-01-01

    of optimisation techniques coupled with dynamic solution of the underlying model. Linear and nonlinear approaches to parameter estimation are investigated. There is also the application of maximum likelihood principles in the estimation of parameters, as well as the use of orthogonal collocation to generate a set......In this chapter the importance of parameter estimation in model development is illustrated through various applications related to reaction systems. In particular, rate constants in a reaction system are obtained through parameter estimation methods. These approaches often require the application...... of algebraic equations as the basis for parameter estimation.These approaches are illustrated using estimations of kinetic constants from reaction system models....

  19. Effect of solvent on absorption and fluorescence spectra of a typical fluorinated azo dye for its acidic and basic structures

    Science.gov (United States)

    Abdel-Halim, Shakir T.

    2011-11-01

    The effect of 15 polar solvents on absorption and fluorescence energies of a typical fluorinated azo dye, 4-(2,3,5,6-tetrafluoro-pyridin-4-yl azo)-phenol, was reported for its acidic, MH, and basic, M, structures. For MH, the absorption energy is described on the basis of multi-linear equation with Taft's π* (solvent polarity) and β (hydrogen bond acceptor) parameters while the fluorescence energy varies rectilinearly with free energy of transferring the proton to the surrounding solvent, Δ Gt°. For M, the hydrogen bonding donor ability of protic solvent, α, is a predominant factor which affects the absorption energy while in aprotic solvents, the absorption energy correlates linearly with Kirkwood function. As the ability of the solvent for hydrogen bonding increases, the absorption band width will increase in parallel with the transition energy.

  20. The Solubility Parameters of Ionic Liquids

    Directory of Open Access Journals (Sweden)

    Andrzej Marciniak

    2010-04-01

    Full Text Available The Hildebrand’s solubility parameters have been calculated for 18 ionic liquids from the inverse gas chromatography measurements of the activity coefficients at infinite dilution. Retention data were used for the calculation. The solubility parameters are helpful for the prediction of the solubility in the binary solvent mixtures. From the solubility parameters, the standard enthalpies of vaporization of ionic liquids were estimated.

  1. The influence of the solvent on organic reactivity. Part II. Hydroxylic solvent effects on the reaction rates of diazodiphenylmethane with 2-(2-substituted cyclohex-1-enylacetic and 2-(2-substituted phenylacetic acids

    Directory of Open Access Journals (Sweden)

    VERA V. KRSTIC

    2004-09-01

    Full Text Available The rate constants for the reaction of diazodiphenylmethane with 2-(2-substituted cyclohex-1-enylacetic acids and 2-(2-substituted phenylacetic acids, previously determined in seven hydroxylic solvents, were correlated using the total solvatochromic equation, of the form: log k = log k0 + sp* + aa + bb, the two-parameter model, log log k = log k0 + sp* + aa, and a single parameter model k = log k0 + sp* + bb, where p* is a measure of the solvent polarity, b represents the scale of solvent hydrogen bond acceptor basicities and a represents the scale of solvent hydrogen bond donor acidities. The correlations of the kinetic data were carried out by means of multiple linear regression analysis and the solvent effects on the reaction rates were analysed in terms of initial state and transition state contributions.

  2. Dynamic solvation shell and solubility of C60 in organic solvents.

    Science.gov (United States)

    Wang, Chun I; Hua, Chi C; Chen, Show A

    2014-08-21

    The notion of (static) solvation shells has recently proved fruitful in revealing key molecular factors that dictate the solubility and aggregation properties of fullerene species in polar or ionic solvent media. Using molecular dynamics schemes with carefully evaluated force fields, we have scrutinized both the static and the dynamic features of the solvation shells of single C60 particle for three nonpolar organic solvents (i.e., chloroform, toluene, and chlorobenzene) and a range of system temperatures (i.e., T = 250-330 K). The central findings have been that, while the static structures of the solvation shell remain, in general, insensitive to the effects of changing solvent type or system temperature, the dynamic behavior of solvent molecules within the shell exhibits prominent dependence on both factors. Detailed analyses led us to propose the notion of dynamically stable solvation shell, effectiveness of which can be characterized by a new physical parameter defined as the ratio of two fundamental time constants representing, respectively, the solvent relaxation (or residence) time within the first solvation shell and the characteristic time required for the fullerene particle to diffuse a distance comparable to the shell thickness. We show that, for the five (two from the literature) different solvent media and the range of system temperatures examined herein, this parameter bears a value around unity and, in particular, correlates intimately with known trends of solubility for C60 solutions. We also provide evidence revealing that, in addition to fullerene-solvent interactions, solvent-solvent interactions play an important role, too, in shaping the dynamic solvation shell, as implied by recent experimental trends.

  3. Additive diffusion from LDPE slabs into contacting solvents as a function of solvent absorption

    NARCIS (Netherlands)

    Helmroth, I.E.; Dekker, M.; Hankemeier, Th.

    2003-01-01

    This article describes the simultaneous diffusion of a migrant and a solvent in low density polyethylene (LDPE). The migrant (Irganox 1076) moves out of the slab, while the solvent (isooctane, n-heptane or cyclohexane) moves inwards. Solvent absorption was measured separately by following the increa

  4. Additive Diffusion from LDPE Slabs into Contacting Solvents as a Function of Solvent Absorption

    NARCIS (Netherlands)

    Helmroth, I.E.; Dekker, M.; Hankemeier, T.

    2003-01-01

    This article describes the simultaneous diffusion of a migrant and a solvent in low density polyethylene (LDPE). The migrant (Irganox 1076) moves out of the slab, while the solvent (isooctane, n-heptane or cyclohexane) moves inwards. Solvent absorption was measured separately by following the increa

  5. Solvent effect in the Walden inversion reactions

    Science.gov (United States)

    Jaume, J.; Lluch, J. M.; Oliva, A.; Bertrán, J.

    1984-04-01

    The solvent effect on the fluoride exchange reaction has been studied by means of ab initio calculations using the 3-21G basis set. It is shown that the motion of the solvent molecules is an important part of the reaction coordinate.

  6. Solvation of rhodamine575 in some solvents

    Science.gov (United States)

    Sharma, Amit

    2016-05-01

    FTIR spectra of Rhodamine575 dye in powder form and in different solvents are reported. Positions of some of the observed FTIR bands show noticeable change in solvents. The bands, which shift, have contributions from the vibrational motion of nitrogen atoms of the ethylamine groups, oxygen atom of the carboxylic group attached to the phenyl ring and oxygen atom of the Xanthene ring.

  7. Composite capillary membrane for solvent resistant nanofiltration

    NARCIS (Netherlands)

    Dutczak, S.M.; Luiten-Olieman, Maria W.J.; Zwijnenberg, Harmen Jan; Bolhuis-Versteeg, Lydia A.M.; Winnubst, Aloysius J.A.; Hempenius, Mark A.; Benes, Nieck Edwin; Wessling, Matthias; Stamatialis, Dimitrios

    2011-01-01

    Solvent resistant nanofiltration (SRNF) is a membrane separation process allowing for an efficient separation of small molecules of 200–1000 g mol−1 from organic solvents. The application of SRNF in industry applications is currently hindered by a limited choice of SRNF membranes and configurations.

  8. Improved Supercritical-Solvent Extraction of Coal

    Science.gov (United States)

    Compton, L.

    1982-01-01

    Raw coal upgraded by supercritical-solvent extraction system that uses two materials instead of one. System achieved extraction yields of 20 to 49 weight percent. Single-solvent yields are about 25 weight percent. Experimental results show extraction yields may be timedependent. Observed decreases in weight of coal agreed well with increases in ash content of residue.

  9. Solvent-vapor-assisted imprint lithography

    NARCIS (Netherlands)

    Voicu, Nicoleta E.; Ludwigs, Sabine; Crossland, Edward J. W.; Andrew, Piers; Steiner, Ullrich

    2007-01-01

    Sub-micrometer features are replicated into high-molecular-weight polymer resists by using solvent-assisted nanoimprint lithography (see figure). By swelling the polymer in a controlled solvent-vapor atmosphere, millibar pressures and ambient temperatures are sufficient to achieve high-fidelity

  10. Predicting the solubility of drugs in solvent mixtures: multiple solubility maxima and the chameleonic effect.

    Science.gov (United States)

    Escalera, J B; Bustamante, P; Martin, A

    1994-03-01

    An approach to reproduce the solubility profile of a drug in several solvent mixtures showing two solubility maxima is proposed in this work. The solubility of sulphamethoxypyridazine was determined at 25 degrees C in several mixtures of varying polarity (hexane:ethyl acetate, ethyl acetate:ethanol and ethanol:water). Sulphamethoxypyridazine was chosen as a model drug because of its proton-donor and proton-acceptor properties. A plot of the mole fraction of the drug vs the solubility parameter of the solvent mixtures shows two solubility peaks. The two peaks found for sulphamethoxypyridazine demonstrate the chameleonic effect as described by Hoy and suggest that the solute-solvent interaction does not vary uniformly from one mixture to another. The different behaviour of the drug in mixtures of two proton-donor and proton-acceptor solvents (alcohol and water), and in mixtures of one proton acceptor (ethyl acetate) and one proton donor-proton acceptor (ethanol) is rationalized in terms of differences in the proton donor-acceptor ability of the solvent mixtures. An approach based on the acidic and basic partial solubility parameters together with the Hildebrand solubility parameter of the solvent mixtures is developed to reproduce the experimental results quantitatively. The equation predicts the two solubility maxima as found experimentally, and the calculated values closely correspond to the experimental values through the range composition of the solvent mixtures. These results show that the chameleonic effect can be described in a quantitative way in terms of Lewis acid-base interactions; this approach can assist the product formulator to choose the proper solvent mixture for a new drug.

  11. Solvent effects on the absorption spectra of potentially pharmacologically active 5-alkyl-5-arylhydantoins: A structure-property relationship study

    Directory of Open Access Journals (Sweden)

    Hmuda Sleem F.

    2013-01-01

    Full Text Available To obtain an insight into the interactions of potential anticonvulsant drugs with their surrounding, two series of 5-methyl-5-aryl- and 5-ethyl-5-arylhydantoins were synthesized and their absorption spectra were recorded in the region from 200 to 400 nm in a set of selected solvents. The effects of solvent dipolarity/polarizability and solvent-solute hydrogen bonding interactions on the absorption maxima shifts were analyzed by means of the linear solvation energy relationship (LSER concept of Kamlet and Taft. The ratio of the contributions of specific and nonspecific solvent-solute interactions were correlated with the corresponding ADME properties of the studied compounds. The correlation equations were combined with different physicochemical parameters to generate new equations, which demonstrate the reasonable relationships between solvent-solute interactions and the structure-activity parameters. [Projekat Ministarstva nauke Republike Srbije, br. 172013

  12. Toxic hepatitis in occupational exposure to solvents

    Institute of Scientific and Technical Information of China (English)

    Giulia Malaguarnera; Emanuela Cataudella; Maria Giordano; Giuseppe Nunnari; Giuseppe Chisari; Mariano Malaguarnera

    2012-01-01

    The liver is the main organ responsible for the metabolism of drugs and toxic chemicals,and so is the primary target organ for many organic solvents.Work activities with hepatotoxins exposures are numerous and,moreover,organic solvents are used in various industrial processes.Organic solvents used in different industrial processes may be associated with hepatotoxicity.Several factors contribute to liver toxicity; among these are:species differences,nutritional condition,genetic factors,interaction with medications in use,alcohol abuse and interaction,and age.This review addresses the mechanisms of hepatotoxicity.The main pathogenic mechanisms responsible for functional and organic damage caused by solvents are:inflammation,dysfunction of cytochrome P450,mitochondrial dysfunction and oxidative stress.The health impact of exposure to solvents in the workplace remains an interesting and worrying question for professional health work.

  13. Assessment of solvents for cellulose dissolution.

    Science.gov (United States)

    Ghasemi, Mohammad; Tsianou, Marina; Alexandridis, Paschalis

    2017-03-01

    A necessary step in the processing of biomass is the pretreatment and dissolution of cellulose. A good solvent for cellulose involves high diffusivity, aggressiveness in decrystallization, and capability of disassociating the cellulose chains. However, it is not clear which of these factors and under what conditions should be improved in order to obtain a more effective solvent. To this end, a newly-developed phenomenological model has been applied to assess the controlling mechanism of cellulose dissolution. Among the findings, the cellulose fibers remain crystalline almost to the end of the dissolution process for decrystallization-controlled kinetics. In such solvents, decreasing the fiber crystallinity, e.g., via pretreatment, would result in a considerable increase in the dissolution rate. Such insights improve the understanding of cellulose dissolution and facilitate the selection of more efficient solvents and processing conditions for biomass. Specific examples of solvents are provided where dissolution is limited due to decrystallization or disentanglement.

  14. Preparation of coal slurry with organic solvents.

    Science.gov (United States)

    Shin, Yu-Jen; Shen, Yun-Hwei

    2007-06-01

    In this study, various organic solvents were used to prepare coal slurries and the rheological and thermal properties of coal-organic solvent slurries were examined. Solvents with molecules containing unpaired electrons (high basicity) show high extraction power and cause swelling of coal. Therefore, coal-organic solvent slurries usually showed higher viscosities compared to coal-water slurry. In addition, coal slurries prepared by alcohols and cyclohexanone demonstrated lower settling rates but a high specific sedimentation volume presumably because these solvents swelled coal particles well and led to the formation of weak gel structures in the bulk. In addition, ethanol and cyclohexanone are capable of breaking a considerable amount of hydrogen bonds in coal and subsequently opening up the structures. Thus, more surface area is available for combustion and the combustion rate of coal slurries was increased.

  15. Efficient cellulose solvent: quaternary ammonium chlorides.

    Science.gov (United States)

    Kostag, Marc; Liebert, Tim; El Seoud, Omar A; Heinze, Thomas

    2013-10-01

    Pure quaternary tetraalkylammonium chlorides with one long alkyl chain dissolved in various organic solvents constitute a new class of cellulose solvents. The electrolytes are prepared in high yields and purity by Menshutkin quaternization, an inexpensive and easy synthesis route. The pure molten tetraalkylammonium chlorides dissolve up to 15 wt% of cellulose. Cosolvents, including N,N-dimethylacetamide (DMA), may be added in large excess, leading to a system of decreased viscosity. Contrary to the well-established solvent DMA/LiCl, cellulose dissolves in DMA/quaternary ammonium chlorides without any pretreatment. Thus, the use of the new solvent avoids some disadvantages of DMA/LiCl and ionic liquids, the most extensively employed solvents for homogeneous cellulose chemistry.

  16. Green-solvent-processable organic solar cells

    Directory of Open Access Journals (Sweden)

    Shaoqing Zhang

    2016-11-01

    Full Text Available Solution-processable organic photovoltaics (OPV has emerged as a promising clean energy-generating technology due to its potential for low-cost manufacturing with a high power/weight ratio. The state-of-the-art OPV devices are processed by hazardous halogenated solvents. Fabricating high-efficiency OPV devices using greener solvents is a necessary step toward their eventual commercialization. In this review, recent research efforts and advances in green-solvent-processable OPVs are summarized, and two basic strategies including material design and solvent selection of light-harvesting layers are discussed. In particular, the most recent green-solvent-processable OPVs with high efficiencies in excess of 9% are highlighted.

  17. [Neurotoxicity of organic solvents--recent findings].

    Science.gov (United States)

    Matsuoka, Masato

    2007-06-01

    In this review, the recent findings of central nervous system (CNS) or peripheral nervous system (PNS) dysfunction induced by occupational exposure to organic solvents are described. While acute, high-level exposure to almost all organic solvents causes the general, nonspecific depression of CNS, it is still not clear whether chronic, low-level occupational exposure causes the chronic neurological dysfunction which has been called "organic solvent syndrome", "painters syndrome", "psycho-organic syndrome" or "chronic solvent encephalopathy". At least at lower than occupational exposure limits, chronic and low-level organic solvent exposure does not appear to cause the "sy mptomatic" neurological dysfunction. The chronic, moderate- to high-level exposure to a few organic solvents (such as carbon disulfide, n-hexane and methyl n-butyl ketone) affects CNS or PNS specifically. The substitutes for chlorofluorocarbons, 2-bromopropane and 1-bromopropane were shown to have the peripheral nerve toxicity in the experimental animals. Shortly after these observations, human cases of 1-bromopropane intoxication with the dysfunction of CNS and PNS were reported in the United States. Neurological abnormalities in workers of a 1-bromopropane factory in China were also reported. Thus, the possible neurotoxicity of newly introduced substitutes for ozone-depleting solvents into the workplace must be considered. Enough evidences indicate that some common solvents (such as toluene and styrene) induce sensorineural hearing loss and acquired color vision disturbances in workers. In some studies using magnetic resonance imaging (MRI), cerebral atrophy, patchy periventricular hyperintensities and hypointensities in the basal ganglia were found in solvent-exposed workers as have been shown in toluene abusers (toluene leukoencephalopathy). Further studies using the neurobehavioral test batteries, neurophysiological measurements and advanced neuroimaging techniques are required to detect the

  18. The chemistry of nonaqueous solvents v.4 solution phenomena and aprotic solvents

    CERN Document Server

    Lagowski, J J

    1976-01-01

    The Chemistry of Nonaqueous Solvents, Volume IV: Solution Phenomena and Aprotic Solvents focuses on the chemistry of nonaqueous solvents, with emphasis on solution phenomena and aprotic solvents such as tetramethylurea, inorganic acid chlorides, cyclic carbonates, and sulfolane. This book is organized into seven chapters and begins with an overview of the theory of electrical conductivity and elementary experimental considerations, along with some of the interesting research on nonaqueous solvents. It then turns to a discussion on hydrogen bonding phenomena in nonaqueous systems as probed

  19. PARIS II: Computer Aided Solvent Design for Pollution Prevention

    Science.gov (United States)

    This product is a summary of U.S. EPA researchers' work developing the solvent substitution software tool PARIS II (Program for Assisting the Replacement of Industrial Solvents, version 2.0). PARIS II finds less toxic solvents or solvent mixtures to replace more toxic solvents co...

  20. Kinetic solvent effects on hydrogen abstraction from phenol by the cumyloxyl radical. Toward an understanding of the role of protic solvents.

    Science.gov (United States)

    Bietti, Massimo; Salamone, Michela; DiLabio, Gino A; Jockusch, Steffen; Turro, Nicholas J

    2012-02-03

    A time-resolved kinetic study of the hydrogen atom abstraction reactions from phenol by the cumyloxyl radical (CumO(•)) was carried out in different solvents. The hydrogen atom abstraction rate constant (k(H)) was observed to decrease by almost 3 orders of magnitude on going from isooctane to MeOH. In TFE, MeCN/H(2)O 2:1, and MeOH, the measured k(H) values were lower than expected on the basis of the Snelgrove-Ingold (SI) equation that correlates log k(H) to the solvent hydrogen bond acceptor (HBA) ability parameter β(2)(H). As these solvents also act as hydrogen bond donors (HBDs), we explored the notion that a more thorough description of solvent effects could be provided by including a solvent HBD ability term, α(2)(H), into the SI equation via β(2)(H)(1 + α(2)(H)). The inclusion of such a term greatly improves the fitting for TFE, MeCN/H(2)O 2:1, and MeOH but at the expense of that for tertiary alkanols. This finding suggests that, for the reaction of CumO(•) with phenol, the HBA and HBD abilities of both the solvent and the substrate could be responsible for the observed KSEs. but this requires that primary and tertiary alkanols exhibit different solvation behaviors. Possible explanations for this different behavior are explored.

  1. Predicting the Solubility of Pharmaceutical Cocrystals in Solvent/Anti-Solvent Mixtures

    Directory of Open Access Journals (Sweden)

    Linda Lange

    2016-05-01

    Full Text Available In this work, the solubilities of pharmaceutical cocrystals in solvent/anti-solvent systems were predicted using PC-SAFT in order to increase the efficiency of cocrystal formation processes. Modeling results and experimental data were compared for the cocrystal system nicotinamide/succinic acid (2:1 in the solvent/anti-solvent mixtures ethanol/water, ethanol/acetonitrile and ethanol/ethyl acetate at 298.15 K and in the ethanol/ethyl acetate mixture also at 310.15 K. The solubility of the investigated cocrystal slightly increased when adding small amounts of anti-solvent to the solvent, but drastically decreased for high anti-solvent amounts. Furthermore, the solubilities of nicotinamide, succinic acid and the cocrystal in the considered solvent/anti-solvent mixtures showed strong deviations from ideal-solution behavior. However, by accounting for the thermodynamic non-ideality of the components, PC-SAFT is able to predict the solubilities in all above-mentioned solvent/anti-solvent systems in good agreement with the experimental data.

  2. Distribution of multi-component solvents in solvent vapor extraction chamber

    Energy Technology Data Exchange (ETDEWEB)

    Das, S. [Society of Petroleum Engineers, Richardson, TX (United States)]|[Marathon Oil Corp., Houston, TX (United States)

    2008-10-15

    Vapex process performance is sensitive to operating pressures, temperatures and the types of solvent used. The hydrocarbon solvents used in Vapex processes typically have between 5 and 10 per cent hydrocarbon impurities, and the accumulation of dense phases inside the vapor chamber reduces gravity drainage potential. This study investigated the partitioning of solvent compounds inside the vapor chamber during in situ Vapex processes.The aim of the study was to examine how the different components of the mixed solvent partitioned inside the extracted chamber during the oil and vapor phase. A 2-D homogenous reservoir model was used to simulate the Vapex process with a solvent mixture comprised of propane and methane at various percentages. The effect of injecting a hot solvent vapor was also investigated. The study showed that injected methane accumulated at both the top and the extraction interface. Accumulations near the top had a positive impact on solvent confinement in thin reservoirs. Diffusion of the solvent component was controlled by gas phase molecular diffusion, and was much faster than the diffusion of solvent molecules in the liquid phase. The use of hot solvent mixtures slowed the extraction process due to lower solvent solubility in the oil phase. It was concluded that the negative impact on viscosity reduction by dilution was not compensated by rises in temperature. 6 refs., 11 figs.

  3. Screening method for solvent selection used in tar removal by the absorption process.

    Science.gov (United States)

    Masurel, Eve; Authier, Olivier; Castel, Christophe; Roizard, Christine

    2015-01-01

    The aim of this paper is the study of the treatment of flue gas issued from a process of biomass gasification in fluidized bed. The flue gas contains tar which should be selectively removed from the fuel components of interest (e.g. H2, CO and light hydrocarbons) to avoid condensation and deposits in internal combustion engine. The chosen flue gas treatment is the gas-liquid absorption using solvents, which present specific physicochemical properties (e.g. solubility, viscosity, volatility and chemical and thermal stability) in order to optimize the unit on energetic, technico-economic and environmental criteria. The rational choice of the proper solvent is essential for solving the tar issue. The preselection of the solvents is made using a Hansen parameter in order to evaluate the tar solubility and the saturation vapour pressure of the solvent is obtained using Antoine law. Among the nine families of screened solvents (alcohols, amines, ketones, halogenates, ethers, esters, hydrocarbons, sulphured and chlorinates), acids methyl esters arise as solvents of interest. Methyl oleate has then been selected and studied furthermore. Experimental liquid-vapour equilibrium data using bubbling point and absorption cell measurements and theoretical results obtained by the UNIFAC-Dortmund model confirm the high potential of this solvent and the good agreement between experimental and theoretical results.

  4. Articulatory Parameters.

    Science.gov (United States)

    Ladefoged, Peter

    1980-01-01

    Summarizes the 16 parameters hypothesized to be necessary and sufficient for linguistic phonetic specifications. Suggests seven parameters affecting tongue shapes, three determining the positions of the lips, one controlling the position of the velum, four varying laryngeal actions, and one controlling respiratory activity. (RL)

  5. Parameter Estimation

    DEFF Research Database (Denmark)

    Sales-Cruz, Mauricio; Heitzig, Martina; Cameron, Ian;

    2011-01-01

    of optimisation techniques coupled with dynamic solution of the underlying model. Linear and nonlinear approaches to parameter estimation are investigated. There is also the application of maximum likelihood principles in the estimation of parameters, as well as the use of orthogonal collocation to generate a set...

  6. Energy requirements for wet solvent extraction of lipids from microalgal biomass.

    Science.gov (United States)

    Martin, Gregory J O

    2016-04-01

    Biofuel production from microalgae requires energy efficient processes for extracting and converting triacylglyceride lipids to fuel, compatible with coproduction of protein feeds and nutraceuticals. Wet solvent extraction involves mechanical cell rupture, lipid extraction via solvent contacting, physical phase separation, thermal solvent recovery, and transesterification. A detailed analysis of the effect of key process parameters on the parasitic energy demand of this process was performed. On a well-to-pump basis, between 16% and 320% of the resultant biodiesel energy was consumed depending solely on the process parameters. Highly positive energy balances can be achieved, but only if a correctly designed process is used. This requires processing concentrated biomass (ca 25%w/w) with a high triacylglyceride content (ca 30%w/w), and an efficient extraction process employing a non-polar solvent, low solvent-to-paste ratio, and efficient energy recovery. These requirements preclude many laboratory scale processes and polar co-solvents as viable options for large-scale biofuel production. Copyright © 2016 Elsevier Ltd. All rights reserved.

  7. Organic Solvent Tolerant Lipases and Applications

    Directory of Open Access Journals (Sweden)

    Shivika Sharma

    2014-01-01

    Full Text Available Lipases are a group of enzymes naturally endowed with the property of performing reactions in aqueous as well as organic solvents. The esterification reactions using lipase(s could be performed in water-restricted organic media as organic solvent(s not only improve(s the solubility of substrate and reactant in reaction mixture but also permit(s the reaction in the reverse direction, and often it is easy to recover the product in organic phase in two-phase equilibrium systems. The use of organic solvent tolerant lipase in organic media has exhibited many advantages: increased activity and stability, regiospecificity and stereoselectivity, higher solubility of substrate, ease of products recovery, and ability to shift the reaction equilibrium toward synthetic direction. Therefore the search for organic solvent tolerant enzymes has been an extensive area of research. A variety of fatty acid esters are now being produced commercially using immobilized lipase in nonaqueous solvents. This review describes the organic tolerance and industrial application of lipases. The main emphasis is to study the nature of organic solvent tolerant lipases. Also, the potential industrial applications that make lipases the biocatalysts of choice for the present and future have been presented.

  8. Polar Solvents Trigger Formation of Reverse Micelles.

    Science.gov (United States)

    Khoshnood, Atefeh; Firoozabadi, Abbas

    2015-06-09

    We use molecular dynamics simulations and molecular thermodynamics to investigate the formation of reverse micelles in a system of surfactants and nonpolar solvents. Since the early observation of reverse micelles, the question has been whether the existence of polar solvent molecules such as water is the driving force for the formation of reverse micelles in nonpolar solvents. In this work, we use a simple coarse-grained model of surfactants and solvents to show that a small number of polar solvent molecules triggers the formation of large permanent aggregates. In the absence of polar molecules, both the thermodynamic model and molecular simulations show that small aggregates are more populated in the solution and larger ones are less frequent as the system evolves over time. The size and shape of reverse micelles depend on the size of the polar core: the shape is spherical for a large core and ellipsoidal for a smaller one. Using the coarse-grained model, we also investigate the effect of temperature and surfactant tail length. Our results reveal that the number of surfactant molecules in the micelle decreases as the temperature increases, but the average diameter does not change because the size of the polar core remains invariant. A reverse micelle with small polar core attracts fewer surfactants when the tail is long. The uptake of solvent particles by a micelle of longer surfactant tail is less than shorter ones when the polar solvent particles are initially distributed randomly.

  9. Auditory dysfunction associated with solvent exposure

    Directory of Open Access Journals (Sweden)

    Fuente Adrian

    2013-01-01

    Full Text Available Abstract Background A number of studies have demonstrated that solvents may induce auditory dysfunction. However, there is still little knowledge regarding the main signs and symptoms of solvent-induced hearing loss (SIHL. The aim of this research was to investigate the association between solvent exposure and adverse effects on peripheral and central auditory functioning with a comprehensive audiological test battery. Methods Seventy-two solvent-exposed workers and 72 non-exposed workers were selected to participate in the study. The test battery comprised pure-tone audiometry (PTA, transient evoked otoacoustic emissions (TEOAE, Random Gap Detection (RGD and Hearing-in-Noise test (HINT. Results Solvent-exposed subjects presented with poorer mean test results than non-exposed subjects. A bivariate and multivariate linear regression model analysis was performed. One model for each auditory outcome (PTA, TEOAE, RGD and HINT was independently constructed. For all of the models solvent exposure was significantly associated with the auditory outcome. Age also appeared significantly associated with some auditory outcomes. Conclusions This study provides further evidence of the possible adverse effect of solvents on the peripheral and central auditory functioning. A discussion of these effects and the utility of selected hearing tests to assess SIHL is addressed.

  10. Solvent Effect on the Photolysis of Riboflavin.

    Science.gov (United States)

    Ahmad, Iqbal; Anwar, Zubair; Ahmed, Sofia; Sheraz, Muhammad Ali; Bano, Raheela; Hafeez, Ambreen

    2015-10-01

    The kinetics of photolysis of riboflavin (RF) in water (pH 7.0) and in organic solvents (acetonitrile, methanol, ethanol, 1-propanol, 1-butanol, ethyl acetate) has been studied using a multicomponent spectrometric method for the assay of RF and its major photoproducts, formylmethylflavin and lumichrome. The apparent first-order rate constants (k obs) for the reaction range from 3.19 (ethyl acetate) to 4.61 × 10(-3) min(-1) (water). The values of k obs have been found to be a linear function of solvent dielectric constant implying the participation of a dipolar intermediate along the reaction pathway. The degradation of this intermediate is promoted by the polarity of the medium. This indicates a greater stabilization of the excited-triplet states of RF with an increase in solvent polarity to facilitate its reduction. The rate constants for the reaction show a linear relation with the solvent acceptor number indicating the degree of solute-solvent interaction in different solvents. It would depend on the electron-donating capacity of RF molecule in organic solvents. The values of k obs are inversely proportional to the viscosity of the medium as a result of diffusion-controlled processes.

  11. Density and viscosity of magnesium sulphate in formamide + ethylene glycol mixed solvents

    Indian Academy of Sciences (India)

    A Ali; A K Nain; N Kumar; M Ibrahim

    2002-10-01

    Densities () and viscosities () of different strengths of magnesium sulphate (MgSO4) in varying proportions of formamide (FA) + ethylene glycol as mixed solvents were measured at room temperature. The experimental values of and were used to calculate the values of the apparent molar volume, (), partial molar volume, (°) at infinite dilution, - and $B$-coefficients of the Jones-Dole equation and free energies of activation of viscous flow, ($\\Delta \\mu^{0\\ast}_{1}$) and ($\\Delta \\mu^{0\\ast}_{2}$), per mole of solvent and solute respectively. The behaviour of these parameters suggests strong ion-solvent interactions in these systems and also that MgSO4 acts as structure-maker in FA + ethylene glycol mixed solvents.

  12. Effect of solvent extraction on Tunisian esparto wax composition

    Directory of Open Access Journals (Sweden)

    Saâd Inès

    2016-08-01

    Full Text Available The increase of needs for renewable and vegetable based materials will help to drive the market growth of vegetable waxes. Because of their highly variable composition and physicochemical properties, plant waxes have found numerous applications in the: food, cosmetic, candle, coating, polish etc... The aim of this project is to determine the effect of solvent extraction (petroleum ether and ethanol on Tunisian esparto wax composition. The GC-MS was applied in order to determine the waxes compositions. Then, physicochemical parameters of these two samples of waxes: acid value, saponification value, iodine value and melting point were measured in order to deduct their properties and possible fields of uses. Results showed that esparto wax composition depended on the solvent extraction and that major components of the two samples of waxes were: alkanes, esters of fatty acids and phenols. Furthermore, esparto waxes were characterized by an antioxidant and antibacterial activities but the potential of these activities depended on the solvent of wax extraction.

  13. Solvent effects on catalysis by Escherichia coli dihydrofolate reductase.

    Science.gov (United States)

    Loveridge, E Joel; Tey, Lai-Hock; Allemann, Rudolf K

    2010-01-27

    Hydride transfer catalyzed by dihydrofolate reductase (DHFR) has been described previously within an environmentally coupled model of hydrogen tunneling, where protein motions control binding of substrate and cofactor to generate a tunneling ready conformation and modulate the width of the activation barrier and hence the reaction rate. Changes to the composition of the reaction medium are known to perturb protein motions. We have measured kinetic parameters of the reaction catalyzed by DHFR from Escherichia coli in the presence of various cosolvents and cosolutes and show that the dielectric constant, but not the viscosity, of the reaction medium affects the rate of reaction. Neither the primary kinetic isotope effect on the reaction nor its temperature dependence were affected by changes to the bulk solvent properties. These results are in agreement with our previous report on the effect of solvent composition on catalysis by DHFR from the hyperthermophile Thermotoga maritima. However, the effect of solvent on the temperature dependence of the kinetic isotope effect on hydride transfer catalyzed by E. coli DHFR is difficult to explain within a model, in which long-range motions couple to the chemical step of the reaction, but may indicate the existence of a short-range promoting vibration or the presence of multiple nearly isoenergetic conformational substates of enzymes with similar but distinct catalytic properties.

  14. Unimolecular Solvolyses in Ionic Liquid: Alcohol Dual Solvent Systems

    Directory of Open Access Journals (Sweden)

    Elizabeth D. Kochly

    2016-01-01

    Full Text Available A study was undertaken of the solvolysis of pivaloyl triflate in a variety of ionic liquid:alcohol solvent mixtures. The solvolysis is a kΔ process (i.e., a process in which ionization occurs with rearrangement, and the resulting rearranged carbocation intermediate reacts with the alcohol cosolvent via two competing pathways: nucleophilic attack or elimination of a proton. Five different ionic liquids and three different alcohol cosolvents were investigated to give a total of fifteen dual solvent systems. 1H-NMR analysis was used to determine relative amounts of elimination and substitution products. It was found, not surprisingly, that increasing the bulkiness of alcohol cosolvent led to increased elimination product. The change in the amount of elimination product with increasing ionic liquid concentration, however, varied greatly between ionic liquids. These differences correlate strongly, though not completely, to the Kamlet–Taft solvatochromic parameters of the hydrogen bond donating and accepting ability of the solvent systems. An additional factor playing into these differences is the bulkiness of the ionic liquid anion.

  15. Prediction of Corrosion of Alloys in Mixed-Solvent Environments

    Energy Technology Data Exchange (ETDEWEB)

    Anderko, Andrzej [OLI Systems Inc. Morris Plains (United States); Wang, Peiming [OLI Systems Inc. Morris Plains (United States); Young, Robert D. [OLI Systems Inc. Morris Plains (United States); Riemer, Douglas P. [OLI Systems Inc. Morris Plains (United States); McKenzie, Patrice [OLI Systems Inc. Morris Plains (United States); Lencka, Malgorzata M. [OLI Systems Inc. Morris Plains (United States); Babu, Sudarsanam Suresh [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Angelini, Peter [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

    2003-06-05

    Corrosion is much less predictable in organic or mixed-solvent environments than in aqueous process environments. As a result, US chemical companies face greater uncertainty when selecting process equipment materials to manufacture chemical products using organic or mixed solvents than when the process environments are only aqueous. Chemical companies handle this uncertainty by overdesigning the equipment (wasting money and energy), rather than by accepting increased risks of corrosion failure (personnel hazards and environmental releases). Therefore, it is important to develop simulation tools that would help the chemical process industries to understand and predict corrosion and to develop mitigation measures. To create such tools, we have developed models that predict (1) the chemical composition, speciation, phase equilibria, component activities and transport properties of the bulk (aqueous, nonaqueous or mixed) phase that is in contact with the metal; (2) the phase equilibria and component activities of the alloy phase(s) that may be subject to corrosion and (3) the interfacial phenomena that are responsible for corrosion at the metal/solution or passive film/solution interface. During the course of this project, we have completed the following: (1) Development of thermodynamic modules for calculating the activities of alloy components; (2) Development of software that generates stability diagrams for alloys in aqueous systems; these diagrams make it possible to predict the tendency of metals to corrode; (3) Development and extensive verification of a model for calculating speciation, phase equilibria and thermodynamic properties of mixed-solvent electrolyte systems; (4) Integration of the software for generating stability diagrams with the mixed-solvent electrolyte model, which makes it possible to generate stability diagrams for nonaqueous or mixed-solvent systems; (5) Development of a model for predicting diffusion coefficients in mixed-solvent electrolyte

  16. How polar are choline chloride-based deep eutectic solvents?

    Science.gov (United States)

    Pandey, Ashish; Rai, Rewa; Pal, Mahi; Pandey, Siddharth

    2014-01-28

    Developing and characterizing green solvents with low toxicity and cost is one of the most important issues in chemistry. Deep Eutectic Solvents (DESs), in this regard, have shown tremendous promise. Compared to popular organic solvents, DESs possess negligible VOCs and are non-flammable. Compared to ionic liquids, which share many characteristics but are ionic compounds and not ionic mixtures, DESs are cheaper to make, much less toxic and mostly biodegradable. An estimate of the polarity associated with DESs is essential if they are to be used as green alternatives to common organic solvents in industries and academia. As no one physical parameter can satisfactorily represent solute-solvent interactions within a medium, polarity of DESs is assessed through solvatochromic optical spectroscopic responses of several UV-vis absorbance and molecular fluorescence probes. Information on the local microenvironment (i.e., the cybotactic region) that surrounds several solvatochromic probes [betaine dye, pyrene, pyrene-1-carboxaldehyde, 1-anilino-8-naphthalene sulfonate (ANS), p-toluidinyl-6-naphthalene sulfonate (TNS), 6-propionyl-2-(dimethylaminonaphthalene) (PRODAN), coumarin-153, and Nile Red] for four common and popular DESs formed from choline chloride combined with 1,2-ethanediol, glycerol, urea, and malonic acid, respectively, in 1 : 2 molar ratios termed ethaline, glyceline, reline, and maline is obtained and used to assess the effective polarity afforded by each of these DESs. The four DESs as indicated by these probe responses are found to be fairly dipolar in nature. Absorbance probe betaine dye and fluorescence probes ANS, TNS, PRODAN, coumarin-153, and Nile Red, whose solvatochromic responses are based on photoinduced charge-transfer, imply ethaline and glyceline, DESs formed using alcohol-based H-bond donors, to be relatively more dipolar in nature as compared to reline and maline. The pyrene polarity scale, which is based on polarity-induced changes in

  17. Chemical reactions in solvents and melts

    CERN Document Server

    Charlot, G

    1969-01-01

    Chemical Reactions in Solvents and Melts discusses the use of organic and inorganic compounds as well as of melts as solvents. This book examines the applications in organic and inorganic chemistry as well as in electrochemistry. Organized into two parts encompassing 15 chapters, this book begins with an overview of the general properties and the different types of reactions, including acid-base reactions, complex formation reactions, and oxidation-reduction reactions. This text then describes the properties of inert and active solvents. Other chapters consider the proton transfer reactions in

  18. Influence of solvent polarity on the structure of drop-cast electroactive tetra(aniline)-surfactant thin films.

    Science.gov (United States)

    Dane, Thomas G; Bartenstein, Julia E; Sironi, Beatrice; Mills, Benjamin M; Alexander Bell, O; Emyr Macdonald, J; Arnold, Thomas; Faul, Charl F J; Briscoe, Wuge H

    2016-09-21

    The influence of processing conditions on the thin film microstructure is a fundamental question that must be understood to improve the performance of solution-processed organic electronic materials. Using grazing-incidence X-ray diffraction, we have studied the structure of thin films of a tetra(aniline)-surfactant complex prepared by drop-casting from five solvents (hexane, chloroform, tetrahydrofuran, dichloromethane and ethanol), selected to cover a range of polarities. We found that the structure, level of order and degree of orientation relative to the substrate were extremely sensitive to the solvent used. We have attempted to correlate such solvent sensitivity with a variety of solvent physical parameters. Of particular significance is the observation of a sharp structural transition in the thin films cast from more polar solvents; such films presented significantly greater crystallinity as measured by the coherence length and paracrystalline disorder parameter. We attribute this higher structural order to enhanced dissociation of the acid surfactant in the more polar solvents, which in turn promotes complex formation. Furthermore, the more polar solvents provide more effective screening of (i) the attractive ionic interaction between oppositely charged molecules, providing greater opportunity for dynamic reorganisation of the supramolecular aggregates into more perfect structures; and (ii) the repulsive interaction between the positively charged blocks permitting a solvophobic-driven aggregation of the aromatic surfaces during solvent evaporation.

  19. Solvent, temperature and concentration effects on the optical rotatory dispersion of (R)-3-methylcyclohexanone

    Science.gov (United States)

    Alenaizan, Asem; Al-Basheer, Watheq; Musa, Musa M.

    2017-02-01

    Optical rotatory dispersion (ORD) spectra are reported for isolated and solvated (R)-3-methylcyclohexanone (R-3MCH) in 10 solvents, of wide polarity range, and over the spectral range 350-650 nm. Sample concentration effects on ORD spectra of R-3MCH were also recorded and investigated over widely varying concentrations from 2.5 × 10-3 to 2.5 × 10-1 g/mL where an observed sensitivity of optical rotation (OR) to incident light wavelength at low concentrations is correlated to solvent effects. Temperature effects were also studied by recording ORD spectra over the temperature range 0-65 °C in toluene. Recorded specific OR was plotted against various solvent parameters, namely, dipole moment, polarity, refractive index and polarizability to probe solvent effects. Furthermore, solvent effects were studied by incorporating Kamlet's and Taft's solvent parameters in the multi-parametric linear fitting. Theoretically, ORD spectra and populations of optimized geometries of equatorial and axial conformers of R-3MCH were calculated in the gas and solvated phases. All theoretical calculations were performed employing the polarizable continuum model using density functional theoretical and composite scheme (G4) methods with aug-cc-pVTZ and aug-cc-pVDZ basis sets. Net ORD spectra of R-3MCH were generated by the Boltzmann-weighted sum of the contributions of the dominant conformers. Upon comparing theoretical and experimental ORD spectra, a very good agreement is observed for the ORD spectra in the gas phase and high polarity solvents compared to relatively lesser agreement in low polarity solvents.

  20. Inventory parameters

    CERN Document Server

    Sharma, Sanjay

    2017-01-01

    This book provides a detailed overview of various parameters/factors involved in inventory analysis. It especially focuses on the assessment and modeling of basic inventory parameters, namely demand, procurement cost, cycle time, ordering cost, inventory carrying cost, inventory stock, stock out level, and stock out cost. In the context of economic lot size, it provides equations related to the optimum values. It also discusses why the optimum lot size and optimum total relevant cost are considered to be key decision variables, and uses numerous examples to explain each of these inventory parameters separately. Lastly, it provides detailed information on parameter estimation for different sectors/products. Written in a simple and lucid style, it offers a valuable resource for a broad readership, especially Master of Business Administration (MBA) students.

  1. Solvent-Free Synthesis of New Coumarins

    Directory of Open Access Journals (Sweden)

    Redah I. Al-Bayati

    2012-01-01

    Full Text Available A solvent-free synthesis of five series of coumarin derivatives using microwave assistant is presented herein. The synthesized compounds are fully characterized by UV-VIS, FT-IR, and NMR spectroscopy.

  2. "Solvent Effects" in 1H NMR Spectroscopy.

    Science.gov (United States)

    Cavaleiro, Jose A. S.

    1987-01-01

    Describes a simple undergraduate experiment in chemistry dealing with the "solvent effects" in nuclear magnetic resonance (NMR) spectroscopy. Stresses the importance of having students learn NMR spectroscopy as a tool in analytical chemistry. (TW)

  3. Solvent Extraction Developments in Southern Africa

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    The largest solvent-extraction plant in the world at the time, the Nchanga Copper Operation, was in Zambia. The first commercial process using solvent extraction for the refining of the platinum-group metals was in South Africa. More recently, the Southern African region has seen the implementation of solvent extraction for other base metals, precious metals, and specialty metals. These include the world firsts of primary production of zinc at Skorpion Zinc in Namibia and the large-scale refining of gold by Harmony Gold in South Africa. Several other flowsheets that use solvent-extraction technology are currently under commissioning, development, or feasibility study for implementation in this part of the world, including those for the recovery of copper, cobalt, nickel, tantalum, and niobium.

  4. Water as a Solvent for Life

    Science.gov (United States)

    Pohorille, Andrew; Pratt, Lawrence R.

    2015-01-01

    "Follow the water" is our basic strategy in searching for life in the universe. The universality of water as the solvent for living systems is usually justified by arguing that water supports the rich organic chemistry that seeds life, but alternative chemistries are possible in other organic solvents. Here, other, essential criteria for life that have not been sufficiently considered so far, will be discussed.

  5. Biofiltration of solvent vapors from air

    Energy Technology Data Exchange (ETDEWEB)

    Oh, Young-sook.

    1993-01-01

    For various industrial solvent vapors, biofiltration promises to offer a cost-effective emission control technology. Exploiting the full potential of this technology will help attain the goals of the Clean Air Act Amendments of 1990. Concentrating on large volumes of volatile industrial solvents, stable multicomponent microbial enrichments capable of growing a mineral medium with solvent vapors as their only source of carbon and energy were obtained from soil and sewage sludge. These consortia were immobilized on an optimized porous solid support (ground peat moss and perlite). The biofilter material was packed in glass columns connected to an array of pumps and flow meters that allowed the independent variation of superficial velocity and solvent vapor concentrations. In various experiments, single solvents, such as methanol, butanol, acetonitrile, hexane and nitrobenzene, and solvent mixtures, such as benzene-toluene-xylene (BTX) and chlorobenzene-o-dichlorobenzene (CB/DCB) were biofiltered with rates ranging from 15 to334 g solvent removed per m[sup 3] filter volume /h. Pressure drops were low to moderate (0-10 mmHg/m) and with periodic replacement of moisture, the biofiltration activity could be maintained for a period of several months. The experimental data on methanol biofiltration were subjected to mathematical analysis and modeling by the group of Dr. Baltzis at NJIT for a better understanding and a possible scale up of solvent vapor biofilters. In the case of chlorobenzenes and nitrobenzene, the biofilter columns had to be operated with water recirculation in a trickling filter mode. To prevent inactivation of the trickling filter by acidity during CB/DCB removal, pH control was necessary, and the removal rate of CB/DCB was strongly influenced by the flow rate of the recyling water. Nitrobenzene removal in a trickling filter did not require pH control, since the nitro group was reduced and volatilized as ammonia.

  6. Competitive solvent-molecule interactions govern primary processes of diphenylcarbene in solvent mixtures

    Science.gov (United States)

    Knorr, Johannes; Sokkar, Pandian; Schott, Sebastian; Costa, Paolo; Thiel, Walter; Sander, Wolfram; Sanchez-Garcia, Elsa; Nuernberger, Patrick

    2016-10-01

    Photochemical reactions in solution often proceed via competing reaction pathways comprising intermediates that capture a solvent molecule. A disclosure of the underlying reaction mechanisms is challenging due to the rapid nature of these processes and the intricate identification of how many solvent molecules are involved. Here combining broadband femtosecond transient absorption and quantum mechanics/molecular mechanics simulations, we show for one of the most reactive species, diphenylcarbene, that the decision-maker is not the nearest solvent molecule but its neighbour. The hydrogen bonding dynamics determine which reaction channels are accessible in binary solvent mixtures at room temperature. In-depth analysis of the amount of nascent intermediates corroborates the importance of a hydrogen-bonded complex with a protic solvent molecule, in striking analogy to complexes found at cryogenic temperatures. Our results show that adjacent solvent molecules take the role of key abettors rather than bystanders for the fate of the reactive intermediate.

  7. Thermodynamic consistency of the interaction parameter formalism

    Science.gov (United States)

    Srikanth, S.; Jacob, K. T.

    1988-04-01

    The apparent contradiction between the exact nature of the interaction parameter formalism as presented by Lupis and Elliott and the inconsistencies discussed recently by Pelton and Bale arise from the truncation of the Maclaurin series in the latter treatment. The truncation removes the exactness of the expression for the logarithm of the activity coefficient of a solute in a multi-component system. The integrals are therefore path dependent. Formulae for integration along paths of constant Xi, or X i/Xj are presented. The expression for In γsolvent given by Pelton and Bale is valid only in the limit that the mole fraction of solvent tends to one. The truncation also destroys the general relations between interaction parameters derived by Lupis and Elliott. For each specific choice of parameters special relationships are obtained between interaction parameters.

  8. Solvent dependent photophysical properties of dimethoxy curcumin

    Science.gov (United States)

    Barik, Atanu; Indira Priyadarsini, K.

    2013-03-01

    Dimethoxy curcumin (DMC) is a methylated derivative of curcumin. In order to know the effect of ring substitution on photophysical properties of curcumin, steady state absorption and fluorescence spectra of DMC were recorded in organic solvents with different polarity and compared with those of curcumin. The absorption and fluorescence spectra of DMC, like curcumin, are strongly dependent on solvent polarity and the maxima of DMC showed red shift with increase in solvent polarity function (Δf), but the above effect is prominently observed in case of fluorescence maxima. From the dependence of Stokes' shift on solvent polarity function the difference between the excited state and ground state dipole moment was estimated as 4.9 D. Fluorescence quantum yield (ϕf) and fluorescence lifetime (τf) of DMC were also measured in different solvents at room temperature. The results indicated that with increasing solvent polarity, ϕf increased linearly, which has been accounted for the decrease in non-radiative rate by intersystem crossing (ISC) processes.

  9. Caustic-Side Solvent Extraction: Chemical and Physical Properties of the Optimized Solvent

    Energy Technology Data Exchange (ETDEWEB)

    Delmau, L.H.

    2002-10-08

    This work was undertaken to optimize the solvent used in the Caustic Side Solvent Extraction (CSSX) process and to measure key chemical and physical properties related to its performance in the removal of cesium from the alkaline high-level salt waste stored in tanks at the Savannah River Site. The need to adjust the solvent composition arose from the prior discovery that the previous baseline solvent was supersaturated with respect to the calixarene extractant. The following solvent-component concentrations in Isopar{reg_sign} L diluent are recommended: 0.007 M calix[4]arene-bis(tert-octylbenzo-crown-6) (BOBCalixC6) extractant, 0.75 M 1-(2,2,3,3-tetrafluoropropoxy)-3-(4-sec-butylphenoxy)-2-propanol (Cs-7SB) phase modifier, and 0.003 M tri-n-octylamine (TOA) stripping aid. Criteria for this selection included BOBCalixC6 solubility, batch cesium distribution ratios (D{sub Cs}), calculated flowsheet robustness, third-phase formation, coalescence rate (dispersion numbers), and solvent density. Although minor compromises within acceptable limits were made in flowsheet robustness and solvent density, significant benefits were gained in lower risk of third-phase formation and lower solvent cost. Data are also reported for the optimized solvent regarding the temperature dependence of D{sub Cs} in extraction, scrubbing, and stripping (ESS); ESS performance on recycle; partitioning of BOBCalixC6, Cs-7SB, and TOA to aqueous process solutions; partitioning of organic anions; distribution of metals; solvent phase separation at low temperatures; solvent stability to elevated temperatures; and solvent density and viscosity. Overall, the technical risk of the CSSX process has been reduced by resolving previously identified issues and raising no new issues.

  10. Computer-aided tool for solvent selection in pharmaceutical processes: Solvent swap

    DEFF Research Database (Denmark)

    Papadakis, Emmanouil; K. Tula, Anjan; Gernaey, Krist V.

    In the pharmaceutical processes, solvents have a multipurpose role since different solvents can be used in different stages (such as chemical reactions, separations and purification) in the multistage active pharmaceutical ingredients (APIs) production process. The solvent swap and selection task......-aided framework with the objective to assist the pharmaceutical industry in gaining better process understanding. A software interface to improve the usability of the tool has been created also....

  11. Influence of solvent polarity on preferential solvation of molecular recognition probes in solvent mixtures.

    Science.gov (United States)

    Amenta, Valeria; Cook, Joanne L; Hunter, Christopher A; Low, Caroline M R; Vinter, Jeremy G

    2012-12-13

    The association constants for formation of 1:1 complexes between a H-bond acceptor, tri-n-butylphosphine oxide, and a H-bond donor, 4-phenylazophenol, have been measured in a range of different solvent mixtures. Binary mixtures of n-octane and a more polar solvent (ether, ester, ketone, nitrile, sulfoxide, tertiary amide, and halogenated and aromatic solvents) have been investigated. Similar behavior was observed in all cases. When the concentration of the more polar solvent is low, the association constant is identical to that observed in pure n-octane. Once a threshold concentration of the more polar solvent in reached, the logarithm of the association constant decreases in direct proportion to the logarithm of the concentration of the more polar solvent. This indicates that one of the two solutes is preferentially solvated by the more polar solvent, and it is competition with this solvation equilibrium that determines the observed association constant. The concentration of the more polar solvent at which the onset of preferential solvation takes place depends on solvent polarity: 700 mM for toluene, 60 mM for 1,1,2,2-tetrachloroethane, 20 mM for the ether, ester, ketone, and nitrile, 0.2 mM for the tertiary amide, and 0.1 mM for the sulfoxide solvents. The results can be explained by a simple model that considers only pairwise interactions between specific sites on the surfaces of the solutes and solvents, which implies that the bulk properties of the solvent have little impact on solvation thermodynamics.

  12. CHEMICAL STABILITY OF POLYPHENYLENE SULFIDE IN THE NEXT GENERATION SOLVENT FOR CAUSTIC-SIDE SOLVENT EXTRACTION

    Energy Technology Data Exchange (ETDEWEB)

    Fondeur, F.; Fink, S.

    2011-12-08

    The Office of Waste Processing, within the Office of Technology Innovation and Development, is funding the development of an enhanced solvent for deployment at the Savannah River Site for removal of cesium from High Level Waste. For simplicity, this solvent is referred to as the Next Generation Solvent (NGS). The technical effort is collaboration between Oak Ridge National Laboratory (ORNL), Savannah River National Laboratory (SRNL), and Argonne National Laboratory. The initial deployment target envisioned for the technology was within the Modular Caustic-Side Solvent Extraction Unit (MCU). Deployment of a new chemical within an existing facility requires verification that the chemical components are compatible with the installed equipment. In the instance of a new organic solvent, the primary focus is on compatibility of the solvent with polyphenylene sulfide (PPS), the polymer used in the coalescers within MCU. This report provides the data from exposing PPS polymer to NGS. The test was conducted over a three month period. PPS is remarkably stable in the presence of the next generation solvent. Testing showed no indication of swelling or significant leaching. Preferential sorption of the Modifier on PPS was observed but the same behavior occurs with the baseline solvent. Therefore, PPS coalescers exposed to the NGS are expected to perform comparably to those in contact with the baseline solvent.

  13. The use of environmentally sustainable bio-derived solvents in solvent extraction applications-A review

    Institute of Scientific and Technical Information of China (English)

    Zheng Li; Kathryn H. Smith; Geoffrey W. Stevens

    2016-01-01

    Replacement of volatile organic compounds (VOCs) by greener or more environmental y sustainable solvents is becoming increasingly important due to the increasing health and environmental concerns as wel as economic pressures associated with VOCs. Solvents that are derived from biomass, namely bio-derived solvents, are a type of green solvent that have attracted intensive investigations in recent years because of their advantages over con-ventional VOCs, such as low toxicity, biodegradability and renewability. This review aims to summarize the use of bio-derived solvents in solvent extraction applications, with special emphasis given to utilization of biodiesels and terpenes. Compared with the conventional VOCs, the overall performance of these bio-derived solvents is comparable in terms of extraction yields and selectivity for natural product extraction and no difference was found for metal extraction. To date most researchers have focused on laboratory scale thermodynamics studies. Future work is required to develop and test new bio-derived solvents and understand the kinetic performance as well as solvent extraction pilot plant studies.

  14. CHEMICAL STABILITY OF POLYPHENYLENE SULFIDE IN THE NEXT GENERATION SOLVENT FOR CAUSTIC-SIDE SOLVENT EXTRACTION

    Energy Technology Data Exchange (ETDEWEB)

    Fondeur, F.; Fink, S.

    2011-12-08

    The Office of Waste Processing, within the Office of Technology Innovation and Development, is funding the development of an enhanced solvent for deployment at the Savannah River Site for removal of cesium from High Level Waste. For simplicity, this solvent is referred to as the Next Generation Solvent (NGS). The technical effort is collaboration between Oak Ridge National Laboratory (ORNL), Savannah River National Laboratory (SRNL), and Argonne National Laboratory. The initial deployment target envisioned for the technology was within the Modular Caustic-Side Solvent Extraction Unit (MCU). Deployment of a new chemical within an existing facility requires verification that the chemical components are compatible with the installed equipment. In the instance of a new organic solvent, the primary focus is on compatibility of the solvent with polyphenylene sulfide (PPS), the polymer used in the coalescers within MCU. This report provides the data from exposing PPS polymer to NGS. The test was conducted over a three month period. PPS is remarkably stable in the presence of the next generation solvent. Testing showed no indication of swelling or significant leaching. Preferential sorption of the Modifier on PPS was observed but the same behavior occurs with the baseline solvent. Therefore, PPS coalescers exposed to the NGS are expected to perform comparably to those in contact with the baseline solvent.

  15. Influence of Energy on Solvent Diffusion in Polymer/Solvent Systems

    Institute of Scientific and Technical Information of China (English)

    HUHuijun; JIANGWenhua; 等

    2002-01-01

    The Vrentas-Duda free-volume theory has been extensively used to correlate or predict the solvent diffusion coefficient of a polymer/solvent system.The energy term in the free volume diffusion equation is difficult to estimate,so the energy term was usually neglected in previous predictive versions of the free volume diffusion coefficient equation.Recent studies show that the energy effect is very important even above the glass transition temperature of the system. In this paper, a new evaluation method of the energy term is proposed,that is the diffusion energy at different solvent concentrations is assumed to be a linear function of the solvent diffusion energy in pure solvents and that in polymers under the condition that the solvent in infinite dilution.By taking consideration of the influence of energy on the solvent diffustion,the prediction of solvent diffusion coefficient was preformed for three polymer/solvent systems over a wide range of concentrations and temperatures.The results show an improvement on the predictive capability of the free volume diffusion theory.

  16. Simple measurements for prediction of drug release from polymer matrices - Solubility parameters and intrinsic viscosity

    DEFF Research Database (Denmark)

    Madsen, Claus G; Skov, Anders; Baldursdottir, Stefania;

    2015-01-01

    (dl-lactide-co-glycolide) (PLGA) were cast with bovine serum albumin (BSA) as a model drug using different solvents (acetone, dichloromethane, ethanol and water). The amount of released protein from the different matrices was correlated with the Hildebrand and Hansen solubility parameters of the solvents, and the intrinsic......PURPOSE: This study describes how protein release from polymer matrices correlate with simple measurements on the intrinsic viscosity of the polymer solutions used for casting the matrices and calculations of the solubility parameters of polymers and solvents used. METHOD: Matrices of poly...... from PLGA matrices varied depending on the solvent used for casting. The maximum amount of released BSA decreased with higher intrinsic viscosity, and increased with solubility parameter difference between the solvent and polymer used. The solvent used also had an effect on the matrix microstructure...

  17. Effects of solvent and substituent on the electronic absorption spectra of some substituted Schiff bases: a chemometrics study.

    Science.gov (United States)

    Hemmateenejad, Bahram; Yazdani, Mahdieh; Sharghi, Hashem

    2012-06-01

    A series of Schiff bases were studied for their delicate changes in absorption electronic spectra by changing substituents and solvents. UV/vis absorbance spectra of Schiff base derivatives of different substituents ranging from electron withdrawing to electron donating (Br, CF(3), Cl, CN, CO(2)H, F, Me, NO(2), OH, OMe, H) were studied in different solvents (acetonitrile, chloroform, cyclohexane, dioxane, dimethylsulfoxide and methanol). Linear relationships were established to investigate the effect of solute structure and solvatochromic parameters of solvents on the absorbance spectra. Meaningful chemical factors and then regression models were provided utilizing factor analysis (FA) and multiple linear regression (MLR). It was found that the frequency of maximum absorbance was mainly controlled by the solvent's dipolarity/polarizability. The λ(max) of the ortho-nitro derivative represented the largest dependency on solvents' polarity/polarizability so that it can be used as a solvatochromic probe. Copyright © 2012 Elsevier B.V. All rights reserved.

  18. A generalized free-solvent model for the osmotic pressure of multi-component solutions containing protein-protein interactions.

    Science.gov (United States)

    McBride, Devin W; Rodgers, V G J

    2014-07-01

    The free-solvent model has been shown to have excellent predictability of the osmotic pressure for single and binary non-interactive proteins in aqueous solutions. Here the free-solvent model is extended to be more generalized by including the contributions of intra- and inter-protein interactions to the osmotic pressure of a solution in the form of homo- and hetero-multimers. The solute-solvent interactions are considered to be unique for each homo- and hetero-multimer in solution. The effect of the various generalized free-solvent model parameters on the osmotic pressure are examined for a single protein solution with a homo-dimer, a binary protein solution with no protein-protein interactions, and a binary protein solution with a hetero-dimer. Finally, the limitations associated with the generalized free-solvent model are discussed.

  19. Effect of solvent on complexation between Y3+ cation and 4,13-diaza-18-crown-6 in some binary mixed non-aqueous solvents

    Science.gov (United States)

    Mohammadi, M.; Rounaghi, G. H.; Mohajeri, M.; Karimian, F.

    2014-10-01

    The complexation reaction of 4,13-diaza-18-crown-6 (DA18C6) with Y3+ cation was studied in some binary mixed solvent solutions of acetonitrile (AN) with methanol (MeOH), ethanol (EtOH), 2-propanol (2-PrOH) and methyl acetate (MeOAc) at different temperatures by conductometric method. The obtained data show that in all studied solutions the stoichiometry of the complex formed between DA18C6 and Y3+ cation is 1: 1 [ML], but in the case of pure MeOAc, a 2: 1 [ML2] complex is formed in solution upon addition of the ligand to the metal salt solution, and further addition of the ligand results in formation of a M2L2 complex in solution. This results show that the stoichiometry of the composition of the macrocyclic complexes may be affected by the nature of the solvent system. The results obtained in this study show that the stability constant of the resulting 1: 1 [ML] complex in the binary solvent solutions decreases in the order: AN-MeOAc > AN-2PrOH > AN-MeOH > AN-EtOH. A non-linear relationship was observed between the stability constant (log K f ) of [Y(DA18C6)]3+ complex with the composition of the binary mixed solvent solutions. The corresponding standard thermodynamic parameters ( H° c , Δ S° c ) for 1: 1 [ML] complexation reaction between DA18C6 and Y3+ cation were obtained from temperature dependence of the stability constant of the complex. The results show that, in all solvent systems, the (DAI8C6.Y)3+ complex is entropy stabilized, but from enthalpy point of view, depending on the solvent system, it is stabilized or destabilized and the result show that the values of both thermodynamic quantities change with the nature and composition of the binary mixed solvent solutions.

  20. Stability of the Caustic-Side Solvent Extraction (CSSX) Process Solvent: Effect of High Nitrite on Solvent Nitration

    Energy Technology Data Exchange (ETDEWEB)

    Bonnesen, P.V.

    2002-06-26

    The purpose of this investigation was to determine whether nitrated organic compounds could be formed during operation of the Caustic-Side Solvent Extraction (CSSX) process, and whether such compounds would present a safety concern. The CSSX process was developed to remove cesium from alkaline high-level salt waste stored at the US Department of Energy Savannah River Site (SRS). The solvent is composed of the cesium extractant calix[4]arene-bis-(4-tert-octylbenzo-crown-6) (BOBCalixC6), a fluorinated alcohol phase modifier, tri-n-octylamine (TOA), and an isoparaffinic diluent (Iospar{reg_sign}). During the CSSX process, the solvent is expected to be exposed to high concentrations of nitrate and nitrite dissolved in the alkaline waste feed. The solvent will also be exposed to dilute (50 mM) nitric acid solutions containing low concentrations of nitrite during scrubbing, followed by stripping with 1 mM nitric acid. The solvent is expected to last for one year of plant operation, and the temperatures the solvent may experience during the process could range from as low as 15 C to as high as 35 C. Excursions from standard process conditions could result in the solvent experiencing higher temperatures, as well as concentrations of nitrate, nitrite, and most importantly nitric acid, that exceed normal operating conditions. Accordingly, conditions may exist where nitration reactions involving the solvent components, possibly leading to other chemical reactions stemming from nitration reactions, could occur. To model such nitration reactions, the solvent was exposed to the types of nitrate- and nitrite-containing solutions that might be expected to be encountered during the process (even under off-normal conditions), as a function of time, temperature, and concentration of nitrate, nitrite, and nitric acid. The experiments conducted as part of this report were designed to examine the more specific effect that high nitrite concentrations could have on forming nitrated

  1. Extended Hansen approach: calculating partial solubility parameters of solid solutes.

    Science.gov (United States)

    Wu, P L; Beerbower, A; Martin, A

    1982-11-01

    A multiple linear regression method, known as the extended Hansen solubility approach, was used to estimate the partial solubility parameters, delta d, delta p, and delta h for crystalline solutes. The method is useful, since organic compounds may decompose near their melting points, and it is not possible, to determine solubility parameters for these solid compounds by the methods used for liquid solvents. The method gives good partial and total solubility parameters for naphthalene; with related compounds, less satisfactory results were obtained. At least three conditions, pertaining to the regression equation and the solvent systems, must be met in order to obtain reasonable solute solubility parameters. In addition to providing partial solubility parameters, the regression equations afford a calculation of solute solubility in both polar and nonpolar solvents.

  2. Molecular dynamics simulations of organohalide perovskite precursors: solvent effects in the formation of perovskite solar cells.

    Science.gov (United States)

    Gutierrez-Sevillano, Juan José; Ahmad, Shahzada; Calero, Sofía; Anta, Juan A

    2015-09-21

    The stability and desirable crystal formation of organohalide perovskite semiconductors is of utmost relevance to ensure the success of perovskites in photovoltaic technology. Herein we have simulated the dynamics of ionic precursors toward the formation of embryonic organohalide perovskite CH3NH3PbI3 units in the presence of solvent molecules using Molecular Dynamics. The calculations involved, a variable amount of Pb(2+), I(-), and CH3NH3(+) ionic precursors in water, pentane and a mixture of these two solvents. Suitable force fields for solvents and precursors have been tested and used to carry out the simulations. Radial distribution functions and mean square displacements confirm the formation of basic perovskite crystalline units in pure pentane - taken as a simple and archetypal organic solvent. In contrast, simulations in water confirm the stability of the solvated ionic precursors, which prevents their aggregation to form the perovskite compound. We have found that in the case of a water/pentane binary solvent, a relatively small amount of water did not hinder the perovskite formation. Thus, our findings suggest that the cause of the poor stability of perovskite films in the presence of moisture is a chemical reaction, rather than the polar nature of the solvents. Based on the results, a set of force-field parameters to study from first principles perovskite formation and stability, also in the solid phase, is proposed.

  3. Solvent effects on Pt-Ru/C catalyst for methanol electro-oxidation

    Institute of Scientific and Technical Information of China (English)

    Jinwei Chen; Chunping Jiang; Hui Lu; Lan Feng; Xin Yang; Liangqiong Li; Ruilin Wang

    2009-01-01

    Alloying degree,particle size and the level of dispersion are the key structural parameters of Pt-Ru/C catalyst in fuel cells. Solvent(s) used in the preparation process can affect the particle size and alloying degree of the object substance,which lead to a great positive impact on its properties. In this work,three types of solvents and their mixtures were used in preparation of the Pt-Ru/C catalysts by chemical reduction of metal precursors with sodium borohydride at room temperature. The structure of the catalysts was characterized by X-ray diffraction (XRD) and Transmission electron microscopy (TEM). The catalytic activity and stability for methanol electro-oxidation were studied by Cyclic Voltammetry (CV) and Chronoamperometry (CA). Pt-Ru/C catalyst prepared in H_2O or binary solvents of H_2O and isopropanol had large particle size and low alloying degree leading to low catalytic activity and less stability in methanol electro-oxidation. When tetrahydrofuran was added to the above solvent systems,Pt-Ru/C catalyst prepared had smaller particle size and higher alloying degree which resulted in better catalytic activity,lower onset and peak potentials,compared with the above catalysts. Moreover,the catalyst prepared in ternary solvents of isopropanol,water and tetrahydrofuran had the smallest particle size,and the high alloying degree and the dispersion kept unchanged. Therefore,this kind of catalyst showed the highest catalytic activity and good stability for methanol electro-oxidation.

  4. Direct solvent induced microphase separation, ordering and nano-particles infusion of block copolymer thin films

    Science.gov (United States)

    Modi, Arvind; Sharma, Ashutosh; Karim, Alamgir

    2013-03-01

    Kinetics of block copolymer (BCP) microphase separation by thermal annealing is often a challenge to low-cost and faster fabrication of devices because of the slow ordering. Towards the objective of rapid processing and accessing desired nanostructures, we are developing methods that enable a high degree of mobility of BCP phases while maintaining phase separation conditions via control of effective interaction parameter between the blocks in BCP thin films. We study the self-assembly of PS-P2VP thin films in various solvent mixtures. While non-solvent prevents dissolution of film into the bulk solution, the good solvent penetrates the film and makes polymer chains mobile. As a result of controlled swelling and mobility of BCP blocks, solvent annealing of pre-cast BCP thin films in liquid mixture of good solvent and non-solvent is a promising method for rapid patterning of nanostructures. Interestingly, we demonstrate simultaneous BCP microphase separation and infusion of gold nano-particles into selective phase offering a wide range of application from plasmonics to nanoelectronics. University of Akron Research Foundation (UARF)

  5. Molecular transport behaviour of organic solvents through halloysite nanotubes filled ethylene–vinyl acetate copolymer

    Indian Academy of Sciences (India)

    Suvendu Padhi; P Ganga Raju Achary; Nimai C Nayak

    2015-08-01

    The transport behaviour of three organic solvents (benzene, toluene and xylene) through halloysite nanotubes (HNTs) filled ethylene–vinyl acetate (EVA) copolymer composites have been investigated in the temperature range 303–323 K. The effects of HNTs loading, nature of solvent and temperature on the transport behaviour of solvents through composites were studied. It has been observed that all the systems follow a Fickian mode of transport on increasing temperature. The solvent uptake and sorption coefficient decreases with the increase in halloysite loading while diffusion coefficients and permeation coefficients were found to be dependent on the concentration of filler. The percentage of bounds rubber content and swelling ratio decreases up to 7.5 phr filler content, whereas above 7.5 phr filler loading were found to be increased due to poor dispersion of halloysite in EVA copolymer matrix. The transport behaviour of three organic solvents was further validated by their crosslink density values. The thermodynamic parameters such as enthalpy, entropy and free energy of sorption were evaluated. The positive values of free energy indicate the non-spontaneity of the sorption of HNTs filled EVA in aromatic solvents at 303 K.

  6. Micellization of alkyl-propoxy-ethoxylate surfactants in water-polar organic solvent mixtures.

    Science.gov (United States)

    Sarkar, Biswajit; Lam, Stephanie; Alexandridis, Paschalis

    2010-07-06

    The effects of cosolvents (glycerol, ethanol, and isopropanol) on the self-assembly of novel alkyl-propoxy-ethoxylate surfactants in aqueous solutions have been investigated with a focus on the (i) quantification of solvent effects on the critical micelle concentration (cmc), (ii) free-energy contributions to micellization, (iii) local environment in the micellar solution, and (iv) structure of the micelles. The introduction of the polar organic solvents considered in this work into water decreases cohesive forces in the solvent mixture, resulting in an increase in the solubility of the surfactant molecules. As a result, micelle formation becomes less favorable and the cmc increases. The contribution of the cosolvent to the free energy of micellization is positive, and the data for different mixed solvents collapse onto a single straight line when plotted versus a function of the solubility parameters of the surfactant alkyl chains and the mixed solvents. The behavior of the poly(propylene oxide) part of the alkyl-propoxy-ethoxylate surfactants is hydrophilic, albeit less so in the ethanol-water mixed solvent than in plain water. Pyrene fluorescence emission I(1)/I(3) data suggest that the microenvironment in micellar solutions is affected mainly by the cosolvent concentration, not the surfactant degree of ethoxylation. Small-angle X-ray scattering data for both water and ethanol-water surfactant solutions are consistent with oblate ellipsoid micelles and reveal that the introduction of 20% ethanol decreases the micelle long axis by 10-15%.

  7. Lipase catalyzed esterification of glycidol in nonaqueous solvents: solvent effects on enzymatic activity.

    Science.gov (United States)

    Martins, J F; de Sampaio, T C; de Carvalho, I B; Barreiros, S

    1994-06-05

    We studied the effect of organic solvents on the kinetics of porcine pancreatic lipase (pp) for the resolution of racemic glycidol through esterification with butyric acid. We quantified ppl hydration by measuring water sorption isotherms for the enzyme in the solvents/mixtures tested. The determination of initial rates as a function of enzyme hydration revealed that the enzyme exhibits maximum apparent activity in the solvents/mixtures at the same water content (9% to 11% w/w) within the associated experimental error. The maximum initial rates are different in all the media and correlate well with the logarithm of the molar solubility of water in the media, higher initial rates being observed in the solvents/mixtures with lower water solubilities. The data for the mixtures indicate that ppl apparent activity responds to bulk property of the solvent. Measurements of enzyme particle sizes in five of the solvents, as function of enzyme hydration, revealed that mean particle sizes increased with enzyme hydration in all the solvents, differences between solvents being more pronounced at enzyme hydration levels close to 10%. At this hydration level, solvents having a higher water content lead to lower reaction rates; these are the solvents where the mean enzyme particle sizes are greater. Calculation of the observable modulus indicates there are no internal diffusion limitations. The observed correlation between changes in initial rates and changes in external surface area of the enzyme particles suggests that interfacial activation of ppl is only effective at the external surface of the particles. Data obtained for the mixtures indicate that ppl enantioselectivity depends on specific solvent-enzyme interactions. We make reference to ppl hydration and activity in supercritical carbon dioxide.

  8. Solvent Property Induced Morphological Changes of ABA Amphiphilic Triblock Copolymer Micelles in Dilute Solution: A Self-consistent Field Simulation Study

    Institute of Scientific and Technical Information of China (English)

    Juan-juan Fan; Yuan-yuan Han; Jie Cui

    2014-01-01

    The morphological changes of ABA amphiphilic triblock copolymer micelles in dilute solution were systematically studied by tuning the solvent property using self-consistent field simulation.The solvent property was tuned by changing the Flory-Huggins interaction parameters between each type of blocks and solvent,respectively.The simulation results show that by changing the solvent properties,a series of micelle morphologies such as vesicle,cage-like,ring-shaped,rod-like and spherical micelle morphologies can be obtained.Variations of the free energy of the solution system and the surface area of micelles with the Flory-Huggins interaction parameters were calculated to better understand the effect of solvent property on micelle morphologies.In addition,a phase diagram showing the morphological changes of micelles with the Flory-Huggins interaction parameters is provided.

  9. Preparation of Soybean Protein Concentrate with Mixed Solvents of Hexane-Aqueous Alcohol

    Institute of Scientific and Technical Information of China (English)

    Zhang Weinong; Liu Dachuan

    2002-01-01

    Preparation of soybean proteinconcentrate with the mixed solvents of hexane-aqueous alcohol was studied in this paper Theoptimum technology parameters were obtainedby orthogonal tests. The results of experimentsshowed that the qualities of the product weregood not only on taste and color, but also onhigh solubility-NSI value was 48.80%.

  10. A discrete solvent reaction field model for calculating molecular linear response properties in solution

    Science.gov (United States)

    Jensen, Lasse; van Duijnen, Piet Th.; Snijders, Jaap G.

    2003-08-01

    A discrete solvent reaction field model for calculating frequency-dependent molecular linear response properties of molecules in solution is presented. The model combines a time-dependent density functional theory (QM) description of the solute molecule with a classical (MM) description of the discrete solvent molecules. The classical solvent molecules are represented using distributed atomic charges and polarizabilities. All the atomic parameters have been chosen so as to describe molecular gas phase properties of the solvent molecule, i.e., the atomic charges reproduce the molecular dipole moment and the atomic polarizabilities reproduce the molecular polarizability tensor using a modified dipole interaction model. The QM/MM interactions are introduced into the Kohn-Sham equations and all interactions are solved self-consistently, thereby allowing for the solute to be polarized by the solvent. Furthermore, the inclusion of polarizabilities in the MM part allows for the solvent molecules to be polarized by the solute and by interactions with other solvent molecules. Initial applications of the model to calculate the vertical electronic excitation energies and frequency-dependent molecular polarizability of a water molecule in a cluster of 127 classical water molecules are presented. The effect of using different exchange correlation (xc)-potentials is investigated and the results are compared with results from wave function methods combined with a similar solvent model both at the correlated and uncorrelated level of theory. It is shown that accurate results in agreement with correlated wave function results can be obtained using xc-potentials with the correct asymptotic behavior.

  11. Conformation stability, halogen and solvent effects on CO stretching of 4-chloro-3-halogenobenzaldehydes.

    Science.gov (United States)

    Tursun, Mahir; Parlak, Cemal

    2015-04-15

    The effects of halogen and solvent on the conformation and carbonyl stretching of 4-chloro-3-halogenobenzaldehydes [C7H4ClXO; X=F (CFB), Cl (CCB) or Br (CBB)] were investigated using the density functional theory (DFT) method. The B3LYP functional was used by the 6-311+G(3df,p) basis set in combination with the polarizable continuum model (PCM). Computations were focused on the cis and trans isomers of the compounds in 18 different polar or non-polar organic solvents. The theoretical frequencies of the solvent-induced CO stretching vibrations were correlated with the empirical solvent parameters such as the Kirkwood-Bauer-Magat (KBM) equation, the solvent acceptor number (AN), Swain parameters and the linear solvation energy relationships (LSER). The present work explores the effect of both the halogen and medium on the conformational preference and CO vibrational frequency. The findings of this work can be useful to those systems involving changes in the conformations analogous to the compounds studied.

  12. Non-aqueous capillary electrophoresis of drugs: properties and application of selected solvents.

    Science.gov (United States)

    Tjørnelund, J; Hansen, S H

    1999-01-29

    The electrophoretic mobility of selected acidic and basic test solutes have been determined in non-aqueous media prepared by adding various combinations of ammonium acetate, sodium acetate, methane sulphonic acid and acetic acid to acetonitrile, propylene carbonate, methanol, formamide, N-methylformamide, N,N-dimethylformamide and dimethylsulphoxide, respectively. The apparent pH (pH*) of these non-aqueous media have been measured and it was found that pH* is an important factor for the separations in non-aqueous capillary electrophoresis. However, in some solvents the concentration of sodium acetate has a strong influence on the mobility despite very small changes in pH*. Due to the fact that a change in one parameter influences a number of other parameters it is very difficult to conduct systematic studies in non-aqueous media and to compare the migration of the species at fixed pH* values from one solvent to another. Thus pH* is only of value for comparison when used with a specific solvent or solvent mixture. The viscosity of the above-mentioned solvents were measured at various temperatures and means to adjust the viscosity of the non-aqueous media used for capillary electrophoresis are discussed and the separation of ibuprofen and its major metabolites in urine is used as an example.

  13. Solvent influence on the thermodynamics for hydride transfer from bis(diphosphine) complexes of nickel.

    Science.gov (United States)

    Connelly Robinson, Samantha J; Zall, Christopher M; Miller, Deanna L; Linehan, John C; Appel, Aaron M

    2016-06-14

    The thermodynamic hydricity of a metal hydride can vary considerably between solvents. This parameter can be used to determine the favourability of a hydride-transfer reaction, such as the reaction between a metal hydride and CO2 to produce formate. Because the hydricities of these species do not vary consistently between solvents, reactions that are thermodynamically unfavourable in one solvent can be favourable in others. The hydricity of a water-soluble, bis-phosphine nickel hydride complex was compared to the hydricity of formate in water and in acetonitrile. Formate is a better hydride donor than [HNi(dmpe)2](+) by 7 kcal mol(-1) in acetonitrile, and no hydride transfer from [HNi(dmpe)2](+) to CO2 occurs in this solvent. The hydricity of [HNi(dmpe)2](+) is greatly improved in water relative to acetonitrile, in that reduction of CO2 to formate by [HNi(dmpe)2](+) was found to be thermodynamically downhill by 8 kcal mol(-1). Catalysis for the hydrogenation of CO2 was pursued, but the regeneration of [HNi(dmpe)2] under catalytic conditions was unfavourable. However, the present results demonstrate that the solvent dependence of thermodynamic parameters such as hydricity and acidity can be exploited in order to produce systems with balanced or favourable overall thermodynamics. This approach should be advantageous for the design of future water-soluble catalysts.

  14. New Polymeric Membranes for Organic Solvent Nanofiltration

    KAUST Repository

    Aburabie, Jamaliah

    2017-05-01

    The focus of this dissertation was the development, synthesis and modification of polymers for the preparation of membranes for organic solvent nanofiltration. High chemical stability in a wide range of solvents was a key requirement. Membranes prepared from synthesized polymers as well as from commercial polymers were designed and chemically modified to reach OSN requirements. A solvent stable thin-film composite (TFC) membrane is reported, which is fabricated on crosslinked polythiosemicarbazide (PTSC) as substrate. The membranes exhibited high fluxes towards solvents like THF, DMF and DMSO ranging around 20 L/m2 h at 5 bar with a MWCO of around 1000 g/mol. Ultrafiltration PTSC membranes were prepared by non-solvent induced phase separation and crosslinked with GPTMS. The crosslinking reaction was responsible for the formation of an inorganic-type-network that tuned the membrane pore size. The crosslinked membranes acquired high solvent stability in DMSO, DMF and THF with a MWCO above 1300 g/mol. Reaction Induced Phase Separation (RIPS) was introduced as a new method for the preparation of skinned asymmetric membranes. These membranes have two distinctive layers with different morphologies both from the same polymer. The top dense layer is composed of chemically crosslinked polymer chains while the bottom layer is a porous structure formed by non-crosslinked polymer chains. Such membranes were tested for vitamin B12 in solvents after either crosslinking the support or dissolving the support and fixing the freestanding membrane on alumina. Pebax® 1657 was utilized for the preparation of composite membranes by simple coating. Porous PAN membranes were coated with Pebax® 1657 which was then crosslinked using TDI. Crosslinked Pebax® membranes show high stability towards ethanol, propanol and acetone. The membranes were also stable in DMF once crosslinked PAN supports were used. Sodium alginate polymer was investigated for the preparation of thin film composite

  15. The orientation of solvent-dipoles at the surface of the pure solvent

    NARCIS (Netherlands)

    Nedermeijer-Denessen, H.J.M.; Ligny, C.L. de

    1975-01-01

    A method is described for the assessment of the preferential orientation of solvent-dipoles at the surface of the solvent from the surface potential χ and its temperature coefficient, dχ/dT. The method is based on the model of Levine et al. of the Stern inner region at the mercury-water interface in

  16. The orientation of solvent-dipoles at the surface of the pure solvent

    NARCIS (Netherlands)

    Nedermeijer-Denessen, H.J.M.; Ligny, C.L. de

    1975-01-01

    A method is described for the assessment of the preferential orientation of solvent-dipoles at the surface of the solvent from the surface potential χ and its temperature coefficient, dχ/dT. The method is based on the model of Levine et al. of the Stern inner region at the mercury-water interface in

  17. PSE For Solvent Applications: A Generic Computer-aided Solvent Selection and Design Framework

    DEFF Research Database (Denmark)

    Mitrofanov, Igor; Sin, Gürkan; Gani, Rafiqul

    Solvents are widely used across a number of industries in many applications such as separation agents, reaction mediums, cleaning agents and product carriers. Selection of optimal solvents in these applications is mostly based on previous experiences and experimental trial and error. A process sy...

  18. Solvent System Selection Strategies in Countercurrent Separation

    Science.gov (United States)

    Liu, Yang; Friesen, J. Brent; McAlpine, James B.; Pauli, Guido F.

    2015-01-01

    The majority of applications in countercurrent and centrifugal partition chromatography, collectively known as countercurrent separation, are dedicated to medicinal plant and natural product research. In countercurrent separation, the selection of the appropriate solvent system is of utmost importance as it is the equivalent to the simultaneous choice of column and eluent in liquid chromatography. However, solvent system selection is often laborious, involving extensive partition and/or analytical trials. Therefore, simplified solvent system selection strategies that predict the partition coefficients and, thus, analyte behavior are in high demand and may advance both the science of countercurrent separation and its applications. The last decade of solvent system selection theory and applications are critically reviewed, and strategies are classified according to their data input requirements. This offers the practitioner an up-to-date overview of rationales and methods for choosing an efficient solvent system, provides a perspective regarding their accuracy, reliability, and practicality, and discusses the possibility of combining multiple methods for enhanced prediction power. PMID:26393937

  19. Otoneurologic disturbances caused by solvent pollution.

    Science.gov (United States)

    Odkvist, L M; Möller, C; Thuomas, K A

    1992-06-01

    Subjects exposed to industrial solvents may experience vertigo and nausea. Solvents are usually volatile hydrocarbon compounds, which are important parts of everyday life in a modern society. They may also cause neurastenia, personality changes, and reduced intellectual capacity. The syndrome that may develop was formerly named psycho-organic syndrome (POS), but in modern terminology it is called chronic toxic encephalopathy (CTE). The syndrome develops slowly, and during the first years no pathological findings will be found using various test batteries. Somewhat later, when the syndrome still might be reversible, psychometric, auditory, and otoneurologic testing may well unveil disturbances within the posterior fossa structures. Animal experiments suggest one site of effect for solvents to be within the cerebellum and brainstem regions with close relationship to the gamma-amino-butyric acid (GABA) transmission. In the otoneurologic test battery, visual suppression and smooth pursuit are of extreme value, as are some auditory tests such as discrimination of interrupted speech and cortical response audiometry using frequency glides as stimuli. Dynamic posturography and magnetic resonance imaging (MRI) have recently proved valuable in the diagnosis. Research is needed concerning the most efficient test battery for early detection of solvent-induced lesions. During further research it is important to unveil other toxic agents, like heavy metals and alcohol, and their damage to the central nervous system and to make comparisons between these substances and the lesions caused by hydrocarbon solvents.

  20. Chlorinated solvent replacements recycle/recovery review report

    Energy Technology Data Exchange (ETDEWEB)

    Beal, M.; Hsu, D.; McAtee, R.E.; Weidner, J.R. (EG and G Idaho, Inc., Idaho Falls, ID (United States)); Berg, L.; McCandless, F.P.; Waltari, S.; Peterson, C. (Montana State Univ., Bozeman, MT (United States). Dept. of Chemical Engineering)

    1992-08-01

    This report is a literature review of waste solvents recycle/recovery methods and shows the results of solvent separations using membrane and distillation technologies. The experimental solvent recovery methods were conducted on solvent replacements for chlorinated solvents at Montana State University. The literature review covers waste solvents separation using distillation, membranes decantation, filtration, carbon adsorption, solvent extraction, and other vapor-phase separation techniques. The results of this study identify solvent distillation methods as the most common separation technique. The alternative separation methods typically supplement distillation. The study shows the need for industries to identify waste solvent disposal methods and investigate the economics of waste solvent recycling as a possible waste reduction method.

  1. Development of deep eutectic solvents applied in extraction and separation.

    Science.gov (United States)

    Li, Xiaoxia; Row, Kyung Ho

    2016-09-01

    Deep eutectic solvents, as an alternative to ionic liquids, have greener credentials than ionic liquids, and have attracted considerable attention in related chemical research. Deep eutectic solvents have attracted increasing attention in chemistry for the extraction and separation of various target compounds from natural products. This review highlights the preparation of deep eutectic solvents, unique properties of deep eutectic solvents, and synthesis of deep-eutectic-solvent-based materials. On the other hand, application in the extraction and separation of deep eutectic solvents is also included in this report. In this paper, the available data and references in this field are reviewed to summarize the applications and developments of deep eutectic solvents. Based on the development of deep eutectic solvents, an exploitation of new deep eutectic solvents and deep eutectic solvents-based materials is expected to diversify into extraction and separation. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  2. A calorimetric study of energy conversion efficiency of a sonochemical reactor at 500 kHz for organic solvents.

    Science.gov (United States)

    Toma, Maricela; Fukutomi, Satoshi; Asakura, Yoshiyuki; Koda, Shinobu

    2011-01-01

    It would seem that the economic viability is yet to be established for a great number of sonochemical processes, owning to their perfectible ultrasonic equipments. Industrial scale sonoreactors may become more important as a result of mastering the parameters with influence on their energy balance. This work related the solvent type to the energy efficiency as the first step of a complex study aiming to assess the energy balance of sonochemical reactors at 500 kHz. Quantitative measurements of ultrasonic power for water and 10 pure organic solvents were performed by calorimetry for a cylindrically shaped sonochemical reactor with a bottom mounted vibrating plate. It was found that the ultrasonic power is strongly related to the solvent, the energy conversion for organic liquids is half from that of water and there is a drop in energy efficiency for filling levels up to 250 mm organic solvents. Surface tension, viscosity and vapor pressure influence the energy conversion for organic solvents, but it is difficult explain these findings based on physical properties of solvents alone. The apparent intensity of the atomization process shows a good agreement with the experimentally determined values for energy conversion for water and the solvent group studied here. This study revealed that to attain the same ultrasonic power level, more electrical energy is need for organic solvents as compared to water. The energy balance equation has been defined based on these findings by considering an energy term for atomization.

  3. Kinetic solvent effects on hydrogen abstraction reactions from carbon by the cumyloxyl radical. The role of hydrogen bonding.

    Science.gov (United States)

    Bietti, Massimo; Salamone, Michela

    2010-08-20

    A kinetic study of the H-atom abstraction reactions from 1,4-cyclohexadiene and triethylamine by the cumyloxyl radical has been carried out in different solvents. Negligible effects are observed with 1,4-cyclohexadiene, whereas with triethylamine a significant decrease in rate constant (k(H)) is observed on going from benzene to MeOH. A good correlation between log k(H) and the solvent hydrogen bond donor parameter alpha is observed, indicative of an H-bonding interaction between the amine lone pair and the solvent.

  4. Solvent effects on the O-neophyl rearrangement of 1,1-diarylalkoxyl radicals. A laser flash photolysis study.

    Science.gov (United States)

    Bietti, Massimo; Salamone, Michela

    2005-12-09

    [reaction: see text] A laser flash photolysis study has been carried out to assess solvent effects on the O-neophyl rearrangement of 1,1-diarylalkoxyl radicals. The rearrangement rate constant k decreases by increasing solvent polarity and an excellent correlation with negative slope is obtained between log k and the solvent polarity parameter E(T)N. These evidences are in full agreement with the previous indication that the extent of internal charge separation decreases on going from the starting 1,1-diarylalkoxyl radical to the transition state.

  5. Recommended methods for purification of solvents and tests for impurities

    CERN Document Server

    Coetzee, J F

    1982-01-01

    Recommended Methods for Purification of Solvents and Tests for Impurities is a compilation of recommended procedures for purification of solvents and tests for solvent impurities. Ten solvents are covered: acetonitrile, sulfolane, propylene carbonate, dimethyl sulfoxide, dimethylformamide, hexamethylphosphoramide, pyridine, ethylenediamine, N-methylacetamide, and N-methylpropionamide. This book is comprised of 12 chapters and opens with an introduction to general aspects of impurity effects. The rationale for the selection of solvent is explained, and the relative reactivities of solutes in di

  6. Alternative Solvents through Green Chemistry Project

    Science.gov (United States)

    Hintze, Paul E.; Quinn, Jacqueline

    2014-01-01

    Components in the aerospace industry must perform with accuracy and precision under extreme conditions, and surface contamination can be detrimental to the desired performance, especially in cases when the components come into contact with strong oxidizers such as liquid oxygen. Therefore, precision cleaning is an important part of a components preparation prior to utilization in aerospace applications. Current cleaning technologies employ a variety of cleaning agents, many of which are halogenated solvents that are either toxic or cause environmental damage. Thus, this project seeks to identify alternative precision cleaning solvents and technologies, including use of less harmful cleaning solvents, ultrasonic and megasonic agitation, low-pressure plasma cleaning techniques, and supercritical carbon dioxide extraction. Please review all data content found in the Public Data tab located at: https:techport.nasa.govview11697public

  7. Solvent exfoliation of transition metal dichalcogenides: dispersibility of exfoliated nanosheets varies only weakly between compounds.

    Science.gov (United States)

    Cunningham, Graeme; Lotya, Mustafa; Cucinotta, Clotilde S; Sanvito, Stefano; Bergin, Shane D; Menzel, Robert; Shaffer, Milo S P; Coleman, Jonathan N

    2012-04-24

    We have studied the dispersion and exfoliation of four inorganic layered compounds, WS(2), MoS(2), MoSe(2), and MoTe(2), in a range of organic solvents. The aim was to explore the relationship between the chemical structure of the exfoliated nanosheets and their dispersibility. Sonication of the layered compounds in solvents generally gave few-layer nanosheets with lateral dimensions of a few hundred nanometers. However, the dispersed concentration varied greatly from solvent to solvent. For all four materials, the concentration peaked for solvents with surface energy close to 70 mJ/m(2), implying that all four have surface energy close to this value. Inverse gas chromatography measurements showed MoS(2) and MoSe(2) to have surface energies of ∼75 mJ/m(2), in good agreement with dispersibility measurements. However, this method suggested MoTe(2) to have a considerably larger surface energy (∼120 mJ/m(2)). While surface-energy-based solubility parameters are perhaps more intuitive for two-dimensional materials, Hansen solubility parameters are probably more useful. Our analysis shows the dispersed concentration of all four layered materials to show well-defined peaks when plotted as a function of Hansen's dispersive, polar, and H-bonding solubility parameters. This suggests that we can associate Hansen solubility parameters of δ(D) ∼ 18 MPa(1/2), δ(P) ∼ 8.5 MPa(1/2), and δ(H) ∼ 7 MPa(1/2) with all four types of layered material. Knowledge of these properties allows the estimation of the Flory-Huggins parameter, χ, for each combination of nanosheet and solvent. We found that the dispersed concentration of each material falls exponentially with χ as predicted by solution thermodynamics. This work shows that solution thermodynamics and specifically solubility parameter analysis can be used as a framework to understand the dispersion of two-dimensional materials. Finally, we note that in good solvents, such as cyclohexylpyrrolidone, the dispersions are

  8. Solvent-free fluidic organic dye lasers.

    Science.gov (United States)

    Choi, Eun Young; Mager, Loic; Cham, Tran Thi; Dorkenoo, Kokou D; Fort, Alain; Wu, Jeong Weon; Barsella, Alberto; Ribierre, Jean-Charles

    2013-05-06

    We report on the demonstration of liquid organic dye lasers based on 9-(2-ethylhexyl)carbazole (EHCz), so-called liquid carbazole, doped with green- and red-emitting laser dyes. Both waveguide and Fabry-Perot type microcavity fluidic organic dye lasers were prepared by capillary action under solvent-free conditions. Cascade Förster-type energy transfer processes from liquid carbazole to laser dyes were employed to achieve color-variable amplified spontaneous emission and lasing. Overall, this study provides the first step towards the development of solvent-free fluidic organic semiconducting lasers and demonstrates a new kind of optoelectronic applications for liquid organic semiconductors.

  9. NMR spectroscopy using liquid crystal solvents

    CERN Document Server

    Emsley, JW

    2013-01-01

    NMR Spectroscopy using Liquid Crystal Solvents covers the importance of using a liquid crystal solvent in NMR to derive nuclear dipolar spin-spin coupling constants. This book is composed of ten chapters, and begins with a brief description of the features and benefits of liquid crystal in NMR spectroscopic analysis. The succeeding chapters deal with the mode of operation of nuclear spin Hamiltonian for partially oriented molecules and the analysis of NMR spectra of partially oriented molecules, as well as the determination of rigid molecule structure. These topics are followed by discussions

  10. Solvent-resistant microporous polymide membranes

    Science.gov (United States)

    Miller, Warren K.; McCray, Scott B.; Friesen, Dwayne T.

    1998-01-01

    An asymmetric microporous membrane with exceptional solvent resistance and highly desirable permeability is disclosed. The membrane is made by a solution-casting or solution-spinning process from a copolyamic acid comprising the condensation reaction product in a solvent of at least three reactants selected from certain diamines and dianhydrides and post-treated to imidize and in some cases cross-link the copolyamic acid. The membrane is useful as an uncoated membrane for ultrafiltration, microfiltration, and membrane contactor applications, or may be used as a support for a permselective coating to form a composite membrane useful in gas separations, reverse osmosis, nanofiltration, pervaporation, or vapor permeation.

  11. Occupational exposure to solvents and bladder cancer

    DEFF Research Database (Denmark)

    Hadkhale, Kishor; Martinsen, Jan Ivar; Weiderpass, Elisabete;

    2017-01-01

    logistic regression model was used to estimate hazard ratios (HR) and their 95% confidence intervals (95% CI). Increased risks were observed for trichloroethylene (HR 1.23, 95% 95% CI 1.12-1.40), toluene (HR 1.20, 95% CI 1.00-1.38), benzene (HR 1.16, 95% CI 1.04-1.31), aromatic hydrocarbon solvents (HR 1...... of occupational exposure to trichloroethylene, perchloroethylene, aromatic hydrocarbon solvents, benzene and toluene and the risk of bladder cancer. This article is protected by copyright. All rights reserved....

  12. TODGA Process Development: an Improved Solvent Formulation

    Energy Technology Data Exchange (ETDEWEB)

    Geist, Andreas [Forschungszentrum Karlsruhe, Institut fuer Nukleare Entsorgung, 76021 Karlsruhe (Germany); Modolo, Giuseppe [Forschungszentrum Juelich, Institute for Energy Research, Safety Research and Reactor Technology, 52425 Juelich (Germany)

    2009-06-15

    Introduction: TODGA (N,N,N',N'-tetra-n-octyl diglycolamide) is studied in the European ACSEPT project as a promising extractant for actinide separations. A mixture of TODGA and TBP in TPH (a kerosene) [1] was successfully used for spiked and hot continuous counter-current tests for the separation of actinides(III) and lanthanides(III) from PUREX raffinate [2, 3]. Furthermore this solvent composition is used for GANEX (group actinide extraction) process development, i.e., co-extraction of Np, Pu, Am, Cm, and Ln from PUREX raffinate with selective stripping of the actinides [4, 5]. We address two of this solvent's drawbacks by replacing TBP (which acts as phase modifier to prevent third phase formation) with 1-octanol: (1) The presence of a non-CHON compound (TBP); (2) The pronounced co-extraction of nitric acid (e.g., 0.2 M TODGA + 0.5 M TBP in TPH extracts approx. 0.6 M HNO{sub 3} from 4 M HNO{sub 3}). Results: When contacting 0.2 M TODGA in TPH with 0.1 M Nd(NO{sub 3}){sub 3} in 5 M HNO{sub 3}, as little as 3 % vol. 1-octanol suppresses the formation of a third phase. Thus, the following solvent composition is used for further studies: 0.2 M TODGA + 5 % vol. 1-octanol in TPH. Due to the absence of TBP, the amount of HNO{sub 3} extraction is reduced to approx. 50 % as compared to the solvent consisting of 0.2 M TODGA + 0.5 M TBP in TPH. Am(III) and Eu(III) distribution ratios are similar to those with the TODGA + TBP solvent [1]. Loading the solvent by extracting from solutions of up to 0.2 M Nd(NO{sub 3}){sub 3} in 3 M or 4 M HNO{sub 3} confirms a 1:3 stoichiometry of the extracted complex. Further investigations are under way. Conclusion: The improved solvent formulation reduces the HNO{sub 3} co-extraction which may be advantageous especially for GANEX process development. Furthermore, the solvent complies with the CHON principle. 1) G. Modolo, H. Asp, C. Schreinemachers, H. Vijgen, Development of a TODGA based process for partitioning of

  13. Sann: solvent accessibility prediction of proteins by nearest neighbor method.

    Science.gov (United States)

    Joo, Keehyoung; Lee, Sung Jong; Lee, Jooyoung

    2012-07-01

    We present a method to predict the solvent accessibility of proteins which is based on a nearest neighbor method applied to the sequence profiles. Using the method, continuous real-value prediction as well as two-state and three-state discrete predictions can be obtained. The method utilizes the z-score value of the distance measure in the feature vector space to estimate the relative contribution among the k-nearest neighbors for prediction of the discrete and continuous solvent accessibility. The Solvent accessibility database is constructed from 5717 proteins extracted from PISCES culling server with the cutoff of 25% sequence identities. Using optimal parameters, the prediction accuracies (for discrete predictions) of 78.38% (two-state prediction with the threshold of 25%), 65.1% (three-state prediction with the thresholds of 9 and 36%), and the Pearson correlation coefficient (between the predicted and true RSA's for continuous prediction) of 0.676 are achieved An independent benchmark test was performed with the CASP8 targets where we find that the proposed method outperforms existing methods. The prediction accuracies are 80.89% (for two state prediction with the threshold of 25%), 67.58% (three-state prediction), and the Pearson correlation coefficient of 0.727 (for continuous prediction) with mean absolute error of 0.148. We have also investigated the effect of increasing database sizes on the prediction accuracy, where additional improvement in the accuracy is observed as the database size increases. The SANN web server is available at http://lee.kias.re.kr/~newton/sann/.

  14. Kinetics and Thermodynamics of Oil Extraction from Jatropha curcas L. Using Ethanol as a Solvent

    Directory of Open Access Journals (Sweden)

    Silmara Bispo dos Santos

    2015-01-01

    Full Text Available In the study the yield and kinetic and thermodynamic parameters of the oil extraction process from Jatropha curcas L. using ethanol as a solvent were evaluated for different temperatures, moisture contents of the solid phase, and particle sizes. The extraction process yield increased with contact time of solid particles with the solvent until reaching equilibrium (saturation of the solvent, for all the temperatures, moisture contents, and average particle sizes. These parameters significantly influenced (95% confidence the extracted oil yield. A convective mass transfer model was used to simulate the extraction process and estimate the kinetic and thermodynamic parameters. For all conditions evaluated, values of oil yield in the liquid phase close to equilibrium were obtained in approximately 20 min. The variations of enthalpy and entropy were positive, indicating that the process is endothermic and irreversible. Values obtained for the variation in Gibbs free energy showed that the extraction process using ethanol as a solvent is spontaneous and thermodynamically favorable for the moisture content of 0%, where the smaller the average particle size the greater the spontaneity of the process.

  15. EFFECT OF SOLVENT COMPOSITION ON THE SULFONATION DEGREE OF OLY(PHENYLENE OXIDE) (PPO)

    Institute of Scientific and Technical Information of China (English)

    Tong-wen Xu; Wei-hua Yang; Bing-lin He

    2002-01-01

    This paper investigates the possibility of attaining sulphonated poly(phenylene oxide) (SPPO) with a relatively higher sulfonation degree. To achieve this aim, the approach we adopt is to improve the solubility of the final product in the mixed solvent so that the sulfonation may take place between the bulk solutions and PPO powders even at higher sulfonation degree. It is shown that the addition of a proper amount of dimethyl formide (DMF) to the conventional PPO-chloroform system can actually enhance the sulfonation effect. The solvent composition is then correlated with the sulfonation degree based on the solubility parameters. It is interesting to find that solubility parameters between the mixed solvent and the precipitated products keep an approximately unchanged value at about 4.9, which is just equal to that when pure chloroform is used, though the solubility parameters of both solvents increase with the content of DMF in solution. This may be the main reason why the addition of DMF can reduce the precipitation and improve the ion exchange capacity (IEC) of SPPO polymer.

  16. Molecular, vibrational and electronic structure of 4-bromo-2-halogenobenzaldehydes: Halogen and solvent effects

    Science.gov (United States)

    Fernández, David; Parlak, Cemal; Bilge, Metin; Kaya, Mehmet Fatih; Tursun, Mahir; Keşan, Gürkan; Rhyman, Lydia; Ramasami, Ponnadurai; Şenyel, Mustafa

    2017-09-01

    The halogen and solvent effects on the structure of 4-bromo-2-halogenobenzaldehydes [C7H4BrXO; X = F (BFB), Cl (BCB) or Br (BBB)] were investigated by the density functional theory (DFT) and time-dependent density functional theory (TDDFT) methods. The B3LYP functional and HF and MP2 levels of theory were used with the 6-311+G(3df,p) or aug-cc-pVDZ basis sets. Computations were focused on the cis and trans conformers of the investigated compounds in the gas phase and solutions of 18 different polar or non-polar organic solvents. The computed frequencies of the C=O stretching vibration of the compounds were correlated with some empirical solvent parameters such as the Kirkwood-Bauer-Magat (KBM) equation, solvent acceptor number (AN), Swain parameters and linear solvation energy relationships (LSERs). The electronic properties of the compounds were also examined. The present work explores the effects of the medium and halogen on the conformation, geometrical parameters, dipole moment, ν(C=O) vibration, UV data, frontier orbitals and density-of-states diagram of the compounds. The findings of this research can be useful for studies on benzaldehydes.

  17. Factors affecting high-pressure solvent extraction (accelerated solvent extraction) of additives from polymers.

    Science.gov (United States)

    Vandenburg, H J; Clifford, A A; Bartle, K D; Zhu, S A; Carroll, J; Newton, I D; Garden, L M

    1998-05-01

    Irganox 1010 (pentaerythritol tetrakis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)] propionate) is successfully extracted from polypropylene using solvents at high temperatures and pressures in a homemade accelerated solvent extraction system. For example, using freeze-ground polymer, 90% extraction is possible within 5 min with 2-propanol at 150 °C. Extraction curves for 2-propanol and acetone fit well to the "hot ball" model, previously developed for supercritical fluid extraction. Diffusion coefficients are determined for extractions with 2-propanol, acetone, and cyclohexane over a range of temperatures, and the activation energies for the diffusion are 134, 107, and 61 kJ mol(-)(1), respectively. The lower figure for acetone and cyclohexane indicates that these solvents swell the polymer more than does 2-propanol. The polymer dissolves in the solvent at too high a temperature, which causes blockage of the transfer lines. For maximum extraction rates, the highest temperature for each solvent that avoids dissolution of the polymer should be used. The use of mixed solvents is investigated and shows advantages in some cases, with the aim of producing a solvent that will swell the polymer but not dissolve it.

  18. Preferential Solvation of a Highly Medium Responsive Pentacyanoferrate(II) Complex in Binary Solvent Mixtures: Understanding the Role of Dielectric Enrichment and the Specificity of Solute-Solvent Interactions.

    Science.gov (United States)

    Papadakis, Raffaello

    2016-09-08

    In this work, the preferential solvation of an intensely solvatochromic ferrocyanide(II) dye involving a 4,4'-bipyridine-based ligand was examined in various binary solvent mixtures. Its solvatochromic behavior was rationalized in terms of specific and nonspecific solute-solvent interactions. An exceptional case of solvatochromic inversion was observed when going from alcohol/water to amide/water mixtures. These effects were quantified using Onsager's solvent polarity function. Furthermore, the sensitivity of the solvatochromism of the dye was determined using various solvatochromic parameters such as π* expressing the dipolarity/polarizability of solvents and α expressing the hydrogen-bond-donor acidity of solvents. This analysis was useful for the rationalization of the selective solvation phenomena occurring in the three types of alcohol/water and amide/water mixtures studied. Furthermore, two preferential solvation models were employed for the interpretation of the experimental spectral results in binary solvent mixtures, namely, the model of Suppan on dielectric enrichment [J. Chem. Soc. Faraday Trans. 1 1987, 83, 495-509] and the model of Bosch, Rosés, and co-workers [J. Chem. Soc., Perkin Trans. 2, 1995, 8, 1607-1615]. The first model successfully predicted the charge transfer energies of the dye in formamide/water and N-methylformamide/water mixtures, but in the case of MeOH/water mixtures, the prediction was less accurate because of the significant contribution of specific solute-solvent interactions in that case. The second model gave more insights for both specific solute-solvent as well as solvent-solvent interactions in the cybotactic region. The role of dielectric enrichment and specific interactions was discussed based on the findings.

  19. Next Generation Solvent Performance in the Modular Caustic Side Solvent Extraction Process - 15495

    Energy Technology Data Exchange (ETDEWEB)

    Smith, Tara E. [Savannah River Remediation, LLC., Aiken, SC (United States); Scherman, Carl [Savannah River Remediation, LLC., Aiken, SC (United States); Martin, David [Savannah River Remediation, LLC., Aiken, SC (United States); Suggs, Patricia [Savannah River Site (SRS), Aiken, SC (United States)

    2015-01-14

    Changes to the Modular Caustic Side Solvent Extraction Unit (MCU) flow-sheet were implemented in the facility. Implementation included changing the scrub and strip chemicals and concentrations, modifying the O/A ratios for the strip, scrub, and extraction contactor banks, and blending the current BoBCalixC6 extractant-based solvent in MCU with clean MaxCalix extractant-based solvent. During the successful demonstration period, the MCU process was subject to rigorous oversight to ensure hydraulic stability and chemical/radionuclide analysis of the key process tanks (caustic wash tank, solvent hold tank, strip effluent hold tank, and decontaminated salt solution hold tank) to evaluate solvent carryover to downstream facilities and the effectiveness of cesium removal from the liquid salt waste. Results indicated the extraction of cesium was significantly more effective with an average Decontamination Factor (DF) of 1,129 (range was 107 to 1,824) and that stripping was effective. The contactor hydraulic performance was stable and satisfactory, as indicated by contactor vibration, contactor rotational speed, and flow stability; all of which remained at or near target values. Furthermore, the Solvent Hold Tank (SHT) level and specific gravity was as expected, indicating that solvent integrity and organic hydraulic stability were maintained. The coalescer performances were in the range of processing results under the BOBCalixC6 flow sheet, indicating negligible adverse impact of NGS deployment. After the Demonstration period, MCU began processing via routine operations. Results to date reiterate the enhanced cesium extraction and stripping capability of the Next Generation Solvent (NGS) flow sheet. This paper presents process performance results of the NGS Demonstration and continued operations of MCU utilizing the blended BobCalixC6-MaxCalix solvent under the NGS flowsheet.

  20. Supergranular Parameters

    Science.gov (United States)

    Udayashankar, Paniveni

    2016-07-01

    I study the complexity of supergranular cells using intensity patterns from Kodaikanal solar observatory. The chaotic and turbulent aspect of the solar supergranulation can be studied by examining the interrelationships amongst the parameters characterizing supergranular cells namely size, horizontal flow field, lifetime and physical dimensions of the cells and the fractal dimension deduced from the size data. The findings are supportive of Kolmogorov's theory of turbulence. The Data consists of visually identified supergranular cells, from which a fractal dimension 'D' for supergranulation is obtained according to the relation P α AD/2 where 'A' is the area and 'P' is the perimeter of the supergranular cells. I find a fractal dimension close to about 1.3 which is consistent with that for isobars and suggests a possible turbulent origin. The cell circularity shows a dependence on the perimeter with a peak around (1.1-1.2) x 105 m. The findings are supportive of Kolmogorov's theory of turbulence.

  1. Used Solvent Testing and Reclamation. Volume 2. Vapor Degreasing and Precision Cleaning Solvents

    Science.gov (United States)

    1988-12-01

    Dependence of the 1,3-Dioxolane/AlCI 3 Reaction Using Arrhenius’ Law 88 36 Effect of 1,4-Dioxane on Reactor Pressure 91 67 Effect of 1,4-Dioxane on HCI...and spent solvent. This process was performed for all of the three solvents. Inhibitor Kinetic Studies Batch Reactions. Batch reactor kinetic studies...acceptor in chlorinated solvents. It is an 4 80. Levenspiel , Chemical Reaction Engineering, 2nd ed. (John Wiley and Sons, 1972), pp 41-86. 490

  2. Controlling Actinide Hydration in Mixed Solvent Systems: Towards Tunable Solvent Systems to Close the Fuel Cycle

    Energy Technology Data Exchange (ETDEWEB)

    Clark, Sue B. [Washington State Univ., Pullman, WA (United States). Dept. of Chemistry

    2016-10-31

    The goal of this project has been to define the extent of hydration the f-elements and other cations in mixed solvent electrolyte systems. Methanol-water and other mixed solvent systems have been studied, where the solvent dielectric constant was varied systematically. Thermodynamic and spectroscopic studies provide details concerning the energetics of complexation and other reactions of these cations. This information has also been used to advance new understanding of the behavior of these cations in a variety of systems, ranging from environmental studies, chromatographic approaches, and ionization processes for mass spectrometry.

  3. Solvent tuned single molecule dual emission in protic solvents: effect of polarity and H-bonding.

    Science.gov (United States)

    Chevreux, S; Allain, C; Wilbraham, L; Nakatani, K; Jacques, P; Ciofini, I; Lemercier, G

    2015-01-01

    Phen-PENMe2 has recently been proposed as a promising new molecule displaying solvent-tuned dual emission, highlighting an original and newly-described charge transfer model. The study of the photophysical behaviour of this molecule was extended to include protic solvents. The effects of polarity and hydrogen bonding lead to an even more evident dual emission associated with a large multi-emission band in some solvents like methanol, highlighting Phen-PENMe2 as a promising candidate for white light emission.

  4. Computer-Aided Solvent Screening for Biocatalysis

    DEFF Research Database (Denmark)

    Abildskov, Jens; Leeuwen, M.B. van; Boeriu, C.G.;

    2013-01-01

    . Esterification of acrylic acid with octanol is also addressed. Solvents are screened and candidates identified, confirming existing experimental results. Although the examples involve lipases, the method is quite general, so there seems to be no preclusion against application to other biocatalysts....

  5. Selective solvent absorption in coal conversion

    Energy Technology Data Exchange (ETDEWEB)

    Larsen, J.W.; Lapucha, A.; Lazarov, L.; Amui, J.

    1992-04-01

    The objectives of this project are: (1) to determine the importance of the presence of added hydrogen donor compounds within the coal in the first stage of direct liquefaction processes; and (2) to determine the composition of the solvent absorbed by and present within the coal in the first stage of direct coal liquefaction.

  6. Spherical polymer brushes under good solvent conditions

    DEFF Research Database (Denmark)

    Lo Verso, Federica; Egorov, Sergei A.; Milchev, Andrey

    2010-01-01

    A coarse grained model for flexible polymers end-grafted to repulsive spherical nanoparticles is studied for various chain lengths and grafting densities under good solvent conditions by molecular dynamics methods and density functional theory. With increasing chain length, the monomer density...

  7. Organic solvents in electromembrane extraction: recent insights

    DEFF Research Database (Denmark)

    Huang, Chuixiu; Gjelstad, Astrid; Pedersen-Bjergaard, Stig

    2016-01-01

    Electromembrane extraction (EME) was invented in 2006 as a miniaturized sample preparation technique for the separation of ionized species from aqueous samples. This concept has been investigated in different areas of analytical chemistry by different research groups worldwide since the introduct......Electromembrane extraction (EME) was invented in 2006 as a miniaturized sample preparation technique for the separation of ionized species from aqueous samples. This concept has been investigated in different areas of analytical chemistry by different research groups worldwide since...... the introduction. Under the influence of an electrical field, EME is based on electrokinetic migration of the analytes through a supported liquid membrane (SLM), which is an organic solvent immobilized in the pores of the polymeric membrane, and into the acceptor solution. Up to date, close to 150 research...... articles with focus on EME have been published. The current review summarizes the performance of EME with different organic solvents and discusses several criteria for efficient solvents in EME. In addition, the authors highlight their personal perspective about the most promising organic solvents for EME...

  8. Mixed Solvent Reactive Recrystallization of Sodium Carbonate

    NARCIS (Netherlands)

    Gaertner, R.S.

    2005-01-01

    Investigation of the reactive recrystallization of trona (sodium sesquicarbonate) and sodium bicarbonate to sodium carbonate (soda) in a mixed solvent led to the design of several alternative, less energy consumptive, economically very attractive process routes for the production of soda from all pr

  9. THE TRAVELLING SOLVENT METHOD OF CRYSTAL GROWTH

    Science.gov (United States)

    dicumene Electron beam melting of Cr on SiC Wetting studies of Cr on SiC in different ambients Etching studies in molten salts Zone movement studies Ga-GaAs System P-N junction formation by solvent doping

  10. Organic solvent nanofiltration: prospects and application

    Energy Technology Data Exchange (ETDEWEB)

    Volkov, A V; Korneeva, G A; Tereshchenko, Gennadii F [A. V. Topchiev Institute of Petrochemical Synthesis, Russian Academy of Sciences, Moscow (Russian Federation)

    2008-11-30

    The key lines of research in a new field of the membrane science and technology, viz., organic solvent nanofiltration, are considered. The prospects for its use in chemical, petrochemical and food industries are discussed. Attention is focused on membranes developed for this method.

  11. ESES: Software for Eulerian solvent excluded surface.

    Science.gov (United States)

    Liu, Beibei; Wang, Bao; Zhao, Rundong; Tong, Yiying; Wei, Guo-Wei

    2017-03-15

    Solvent excluded surface (SES) is one of the most popular surface definitions in biophysics and molecular biology. In addition to its usage in biomolecular visualization, it has been widely used in implicit solvent models, in which SES is usually immersed in a Cartesian mesh. Therefore, it is important to construct SESs in the Eulerian representation for biophysical modeling and computation. This work describes a software package called Eulerian solvent excluded surface (ESES) for the generation of accurate SESs in Cartesian grids. ESES offers the description of the solvent and solute domains by specifying all the intersection points between the SES and the Cartesian grid lines. Additionally, the interface normal at each intersection point is evaluated. Furthermore, for a given biomolecule, the ESES software not only provides the whole surface area, but also partitions the surface area according to atomic types. Homology theory is utilized to detect topological features, such as loops and cavities, on the complex formed by the SES. The sizes of loops and cavities are measured based on persistent homology with an evolutionary partial differential equation-based filtration. ESES is extensively validated by surface visualization, electrostatic solvation free energy computation, surface area and volume calculations, and loop and cavity detection and their size estimation. We used the Amber PBSA test set in our electrostatic solvation energy, area, and volume validations. Our results are either calibrated by analytical values or compared with those from the MSMS software. © 2017 Wiley Periodicals, Inc.

  12. Solvent-Free Synthesis of Chalcones

    Science.gov (United States)

    Palleros, Daniel R.

    2004-01-01

    The synthesis of twenty different chalcones in the absence of solvent is presented. The results indicated that out of the twenty different chalcones investigated seventeen can be obtained in a matter of minutes by mixing the corresponding benzaldehyde and acetophenone in the presence of solid NaOH in a mortar with pestle.

  13. Hydrogenation of diesel aromatic compounds in supercritical solvent environment

    Directory of Open Access Journals (Sweden)

    E.P. Martins

    2000-09-01

    Full Text Available Reactions under supercritical conditions have been employed in many processes. Furthermore, an increasing number of commercial reactions have been conducted under supercritical or near critical conditions. These reaction conditions offer several advantages when compared to conditions in conventional catalytic processes in liquid-phase, gas-liquid interface, or even some gas-phase reactions. Basically, a supercritical solvent can diminish the reactant’s transport resistance from the bulk region to the catalyst surface due to enhancement of liquid diffusivity values and better solubility than those in different phases. Another advantage is that supercritical solvents permit prompt and easy changes in intermolecular properties in order to modify reaction parameters, such as conversion or selectivity, or even proceed with the separation of reaction products. Diesel fractions from petroleum frequently have larger than desirable quantities of aromatic compounds. Diesel hydrogenation is intended to decrease these quantities, i.e., to increase the quantity of paraffin present in this petroleum fraction. In this work, the hydrogenation of tetralin was studied as a model reaction for the aromatic hydrogenation process. A conventional gas-liquid-solid catalytic process was compared with that of supercritical carbon dioxide substrate under similar conditions. Additionally, an equilibrium conversion diagram was calculated for this reaction in a wide range of temperature and reactant ratios, so as to optimize the operational conditions and improve the results of subsequent experiments. An increase in the rate of reaction at 493 K in supercritical fluid, as compared to that in the conventional process, was observed.

  14. Highly Efficient Enzymatic Preparation of Daidzein in Deep Eutectic Solvents

    Directory of Open Access Journals (Sweden)

    Qi-Bin Cheng

    2017-01-01

    Full Text Available Daidzein, which is scarce in nature, has gained significant attention due to its superior biological activity and bioavailability compared with daidzin. So far, it has been widely used in the medicine and health care products industries. The enzymatic approach for the preparation of daidzein has prevailed, benefitted by its high efficiency and eco-friendly nature. Our present research aimed at providing a preparation method of daidzein by enzymatic hydrolysis of daidzin in a new “green” reaction medium-deep eutectic solvents (DESs. Herein, the DESs were screened via evaluating enzyme activity, enzyme stability and the substrate solubility, and the DES (ChCl/EG 2:1, 30 vol % was believed to be the most appropriate co-solvent to improve the bioconversion efficiency. Based on the yield of daidzein, response surface methodology (RSM was employed to model and optimize the reaction parameters. Under these optimum process conditions, the maximum yield of 97.53% was achieved and the purity of daidzein crude product reached more than 70%, which is more efficient than conversions in DESs-free buffer. Importantly, it has been shown that DESs medium could be reused for six batches of the process with a final conversion of above 50%. The results indicated that this procedure could be considered a mild, environmentally friendly, highly efficient approach to the economical production of daidzein, with a simple operation process and without any harmful reagents being involved.

  15. Enzymic peptide synthesis in microaqueous, solvent-free systems.

    Science.gov (United States)

    Kuhl, P; Elchhorn, U; Jakubke, H D

    1995-02-05

    Thermolysin-catalyzed (EC 3.4.24.4) and chymotrypsin-catalyzed (EC 3.4.21.1) peptide synthesis reactions were accomplished without any organic solvent in the presence of low amounts of water under sonication and fluidization. The systems used are considered to be microaqueous solvent-free ones. The influence of several reaction parameters, such as time, the amount of enzyme, the amount of water in free form or bound as hydration water, and the N/C component ratio, on the vield of the thermolysin-catalyzed synthesis of Z-Phe-Leu-NH(2) (up to 87% yield) was investigated in a sonicated system. Besides Z-Phe-Leu-NH(2), the tripeptide derivatives Ac-Xaa-Trp-Leu-NH(2), (Xaa = Gly, Ala) were also obtained in good yields of 79 and 71% respectively. In the latter case, no hydrolytic side reactions were observed. Using a fluidized-bed reactor, chymotrypsin- and thermolysin-catalyzed syntheses of N-protected di- and tripeptide amides could be perfromed with yields in the range of 10 to 40%. (c) 1995 John Wiley & Sons, Inc.

  16. Hydrogenation of diesel aromatic compounds in supercritical solvent environment

    Energy Technology Data Exchange (ETDEWEB)

    Martins, E.P.; Aranda, D.A.G.; Pessoa, F.L.P. [Universidade Federal, Rio de Janeiro, RJ (Brazil). Escola de Quimica. Dept. de Engenharia Quimica. E-mail: donato@h2o.eq.ufrj.br; pessoa@h2o.eq.ufrj.br; Zotin, J.L. [PETROBRAS, Rio de Janeiro, RJ (Brazil). Centro de Pesquisas. E-mail: zotin@cenpes.petrobras.com.br

    2000-09-01

    Reactions under supercritical conditions have been employed in many processes. Furthermore, an increasing number of commercial reactions have been conducted under supercritical or near critical conditions. These reaction conditions offer several advantages when compared to conditions in conventional catalytic processes in liquid-phase, gas-liquid interface., or even some gas-phase reactions. basically, a supercritical solvent can diminish the reactant's transport resistance from the bulk region to the catalyst surface due to enhancement of liquid diffusivity values and better solubility than those in different phases. Another advantage is that supercritical solvents permit prompt and easy changes in intermolecular properties in order to modify reaction parameters, such as conversion or selectivity, or even proceed with the separation of reaction products. Diesel fractions from petroleum frequently have larger than desirable quantities of aromatic compounds. Diesel hydrogenation is intended to decrease these quantities, to increase the quantity of paraffin present in this petroleum fraction. In this work, the hydrogenation of tetralin was studied as a model reaction for the aromatic hydrogenation process. A conventional gas-liquid-solid catalytic process was compared with that of supercritical carbon dioxide substrate under similar conditions. Additionally, an equilibrium conversion diagram was calculated for this reaction in a wide range of temperature and reactant ratios, so as to optimize the operational conditions and improve the results of subsequent experiments. An increase in the rate of reaction at 493 K in supercritical fluid, as compared to that in the conventional process, was observed. (author)

  17. Effects of organic solvent and solution temperature on electrospun polyvinylidene fluoride nanofibers.

    Science.gov (United States)

    Wei, Kai; Kim, Han-Ki; Kimura, Naotaka; Suzuki, Hiroaki; Satou, Hidekazu; Lee, Ki-Hoon; Park, Young-Hwan; Kim, Ick-Soo

    2013-04-01

    In this study, the Poly(vinylidene fluoride-trifluoethylene) (PVDF) electrospun fibers were successfully prepared by electrospinning. Processing parameters, such as solvents and solution temperature were varied to study their influence on fiber dimensions. Electrospun PVDF fibers were characterized by scanning electron microscope (SEM), Fourier transform infrared spectrophotometer (FT-IR), wide angle X-ray diffraction (WAXD) and differential scanning calorimetry (DSC). The result indicated that the solvent component and temperature have great influence on fiber dimensions. 19% PVDF dissolved in DMF/MEK mixed solvents with the ratio of 8:2 was considered to be most suitable in this study. Furthermore, the increasing of solution temperature can probably induce the formation of beta-phases in electrospun PVDF Fibers.

  18. Optimizing the surface density of polyethylene glycol chains by grafting from binary solvent mixtures

    Science.gov (United States)

    Arcot, Lokanathan; Ogaki, Ryosuke; Zhang, Shuai; Meyer, Rikke L.; Kingshott, Peter

    2015-06-01

    Polyethylene glycol (PEG) brushes are very effective at controlling non-specific deposition of biological material onto surfaces, which is of paramount importance to obtaining successful outcomes in biomaterials, tissue engineered scaffolds, biosensors, filtration membranes and drug delivery devices. We report on a simple 'grafting to' approach involving binary solvent mixtures that are chosen based on Hansen's solubility parameters to optimize the solubility of PEG thereby enabling control over the graft density. The PEG thiol-gold model system enabled a thorough characterization of PEG films formed, while studies on a PEG silane-silicon system examined the versatility to be applied to any substrate-head group system by choosing an appropriate solvent pair. The ability of PEG films to resist non-specific adsorption of proteins was quantitatively assessed by full serum exposure studies and the binary solvent strategy was found to produce PEG films with optimal graft density to efficiently resist protein adsorption.

  19. Solvent density mode instability in non-polar solutions

    Indian Academy of Sciences (India)

    Susmita Kar; Ranjit Biswas; J Chakrabarti

    2008-08-01

    We analyse the origin of the multiple long time scales associated with the long time decay observed in non-polar solvation dynamics by linear stability analysis of solvent density modes where the effects of compressibility and solvent structure are systematically incorporated. The coupling of the solute–solvent interactions at both ground and excited states of the solute with the compressibility and solvent structure is found to have important effects on the time scales. The present theory suggests that the relatively longer time constant is controlled by the solvent compressibility, while the solvent structure at the nearest-neighbour length scale dominates the shorter time constant.

  20. Efficient Regeneration of Physical and Chemical Solvents for CO2 Capture

    Energy Technology Data Exchange (ETDEWEB)

    Tande, Brian [Univ. of North Dakota, Grand Forks, ND (United States); Seames, Wayne [Univ. of North Dakota, Grand Forks, ND (United States); Benson, Steve [Univ. of North Dakota, Grand Forks, ND (United States)

    2013-12-01

    The objective of this project was to evaluate the use of composite polymer membranes and porous membrane contactors to regenerate physical and chemical solvents for capture of carbon dioxide (CO2) from synthesis gas or flue gas, with the goal of improving the energy efficiency of carbon capture. Both a chemical solvent (typical for a post-combustion capture of CO2 from flue gas) and a physical solvent (typical for pre- combustion capture of CO2 from syngas) were evaluated using two bench-scale test systems constructed for this project. For chemical solvents, polytetrafluoroethylene and polypropylene membranes were found to be able to strip CO2 from a monoethanolamine (MEA) solution with high selectivity without significant degradation of the material. As expected, the regeneration temperature was the most significant parameter affecting the CO2 flux through the membrane. Pore size was also found to be important, as pores larger than 5 microns lead to excessive pore wetting. For physical solvents, polydimethyl-siloxane (PDMS)-based membranes were found to have a higher CO2 permeability than polyvinylalcohol (PVOH) based membranes, while also minimizing solvent loss. Overall, however, the recovery of CO2 in these systems is low – less than 2% for both chemical and physical solvents – primarily due to the small surface area of the membrane test apparatus. To obtain the higher regeneration rates needed for this application, a much larger surface area would be needed. Further experiments using, for example, a hollow fiber membrane module could determine if this process could be commercially viable.

  1. Efficient Regeneration of Physical and Chemical Solvents for CO{sub 2} Capture

    Energy Technology Data Exchange (ETDEWEB)

    Tande, Brian; Seames, Wayne; Benson, Steve

    2013-05-31

    The objective of this project was to evaluate the use of composite polymer membranes and porous membrane contactors to regenerate physical and chemical solvents for capture of carbon dioxide (CO{sub 2}) from synthesis gas or flue gas, with the goal of improving the energy efficiency of carbon capture. Both a chemical solvent (typical for a post-combustion capture of CO{sub 2} from flue gas) and a physical solvent (typical for pre- combustion capture of CO{sub 2} from syngas) were evaluated using two bench-scale test systems constructed for this project. For chemical solvents, polytetrafluoroethylene and polypropylene membranes were found to be able to strip CO{sub 2} from a monoethanolamine (MEA) solution with high selectivity without significant degradation of the material. As expected, the regeneration temperature was the most significant parameter affecting the CO{sub 2} flux through the membrane. Pore size was also found to be important, as pores larger than 5 microns lead to excessive pore wetting. For physical solvents, polydimethyl-siloxane (PDMS)-based membranes were found to have a higher CO{sub 2} permeability than polyvinylalcohol (PVOH) based membranes, while also minimizing solvent loss. Overall, however, the recovery of CO{sub 2} in these systems is low – less than 2% for both chemical and physical solvents – primarily due to the small surface area of the membrane test apparatus. To obtain the higher regeneration rates needed for this application, a much larger surface area would be needed. Further experiments using, for example, a hollow fiber membrane module could determine if this process could be commercially viable.

  2. Morphological control in polymer solar cells using low-boiling-point solvent additives

    Science.gov (United States)

    Mahadevapuram, Rakesh C.

    In the global search for clean, renewable energy sources, organic photovoltaics (OPVs) have recently been given much attention. Popular modern-day OPVs are made from solution-processible, carbon-based polymers (e.g. the model poly(3-hexylthiophene) that are intimately blended with fullerene derivatives (e.g. [6,6]-phenyl-C71-butyric acid methyl ester) to form what is known as the dispersed bulk-heterojunction (BHJ). This BHJ architecture has produced some of the most efficient OPVs to date, with reports closing in on 10% power conversion efficiency. To push efficiencies further into double digits, many groups have identified the BHJ nanomorphology---that is, the phase separations and grain sizes within the polymer: fullerene composite---as a key aspect in need of control and improvement. As a result, many methods, including thermal annealing, slow-drying (solvent) annealing, vapor annealing, and solvent additives, have been developed and studied to promote BHJ self-organization. Processing organic photovoltaic (OPV) blend solutions with high-boiling-point solvent additives has recently been used for morphological control in BHJ OPV cells. Here we show that even low-boiling-point solvents can be effective additives. When P3HT:PCBM OPV cells were processed with a low-boiling-point solvent tetrahydrafuran as an additive in parent solvent o-dichlorobenzene, charge extraction increased leading to fill factors as high as 69.5%, without low work-function cathodes, electrode buffer layers or thermal treatment. This was attributed to PCBM demixing from P3HT domains and better vertical phase separation, as indicated by photoluminescence lifetimes, hole mobilities, and shunt leakage currents. Dependence on solvent parameters and applicability beyond P3HT system was also investigated.

  3. Solvent and temperature induced switching between structural isomers of Rh(I) phosphinoalkyl thioether (PS) complexes.

    Science.gov (United States)

    Wiester, Michael J; Braunschweig, Adam B; Yoo, Hyojong; Mirkin, Chad A

    2010-08-02

    To develop functional systems based on the weak-link approach (WLA), it is important to understand how solvent and ligand binding strength alter the coordination geometry of complexes formed from this method. A series of phosphinoalkyl thioether (PS) hemilabile ligands with varying electron donating abilities were synthesized and incorporated into homoligated Rh(I)(PS)2Cl complexes to help understand the effects of solvent and ligand binding strength on the preferred coordination modes. The switching between closed and semiopen structural isomers of these Rh(I)(PS)2Cl complexes was studied by variable temperature 31P NMR spectroscopy in different solvent mixtures of CH2Cl2 and tetrahydrofuran (THF) to obtain thermodynamic parameters (DeltaG(o), DeltaH(o), TDeltaS(o), and K(eq)). The isomers differ in the position of the chloride counterion. In the closed isomer, the Cl- anion occupies the outer coordination sphere, while in the semiopen isomer, the Cl- has moved inner sphere and displaced one of the Rh-S bonds. The closed isomer is favored in CH2Cl2 and the semiopen isomer is favored in THF. The preference for either isomer at equilibrium depends on the solvent polarity, based upon the E(T)(N) solvent polarity scale, as was determined from 15 different solvents, with more polar solvents favoring the closed isomer. The isomer preference also depends on the electron donating ability of the group attached to the sulfur of the PS ligand, with electron donating groups favoring the closed isomers and electron withdrawing groups favoring the semiopen isomers. The formation of the semiopen isomer from the closed isomer is entropically favored but enthalpically disfavored under all conditions studied. Elucidation of the principles and environments that determine the equilibrium between the two isomers will aid in the design of functional complexes prepared by the WLA.

  4. Toxicity profiles and solvent-toxicant interference in the planarian Schmidtea mediterranea after dimethylsulfoxide (DMSO) exposure.

    Science.gov (United States)

    Stevens, An-Sofie; Pirotte, Nicky; Plusquin, Michelle; Willems, Maxime; Neyens, Thomas; Artois, Tom; Smeets, Karen

    2015-03-01

    To investigate hydrophobic test compounds in toxicological studies, solvents like dimethylsulfoxide (DMSO) are inevitable. However, using these solvents, the interpretation of test compound-induced responses can be biased. DMSO concentration guidelines are available, but are mostly based on acute exposures involving one specific toxicity endpoint. Hence, to avoid solvent-toxicant interference, we use multiple chronic test endpoints for additional interpretation of DMSO concentrations and propose a statistical model to assess possible synergistic, antagonistic or additive effects of test compounds and their solvents. In this study, the effects of both short- (1 day) and long-term (2 weeks) exposures to low DMSO concentrations (up to 1000 µl l(-1) ) were studied in the planarian Schmidtea mediterranea. We measured different biological levels in both fully developed and developing animals. In a long-term exposure set-up, a concentration of 500 µl l(-1) DMSO interfered with processes on different biological levels, e.g. behaviour, stem cell proliferation and gene expression profiles. After short exposure times, 500 µl l(-1) DMSO only affected motility, whereas the most significant changes on different parameters were observed at a concentration of 1000 µl l(-1) DMSO. As small sensitivity differences exist between biological levels and developmental stages, we advise the use of this solvent in concentrations below 500 µl l(-1) in this organism. In the second part of our study, we propose a statistical approach to account for solvent-toxicant interactions and discuss full-scale solvent toxicity studies. In conclusion, we reassessed DMSO concentration limits for different experimental endpoints in the planarian S. mediterranea.

  5. Ionic liquids and deep eutectic solvents in natural products research: mixtures of solids as extraction solvents.

    Science.gov (United States)

    Dai, Yuntao; van Spronsen, Jaap; Witkamp, Geert-Jan; Verpoorte, Robert; Choi, Young Hae

    2013-11-22

    Mixtures of solid chemicals may become liquid under certain conditions. These liquids are characterized by the formation of strong ionic (ionic liquids) or hydrogen bonds (deep eutectic solvents). Due to their extremely low vapor pressure, they are now widely used in polymer chemistry and synthetic organic chemistry, yet little attention has been paid to their use as extraction solvents of natural products. This review summarizes the preparation of ionic liquids and deep eutectic solvents with natural product components and recent progress in their applications to the extraction and analysis of natural products as well as the recovery of extracted compounds from their extracts. Additionally, various factors affecting extraction features of ionic liquids and deep eutectic solvents, as well as potential useful technologies including microwave and ultrasound to increase the extraction efficiency, are discussed.

  6. Effects of polar protic solvents on dual emissions of 3-hydroxychromones

    Indian Academy of Sciences (India)

    Andrey S Klymchenko; Cyril Kenfack; Guy Duportail; Yves Mély

    2007-03-01

    3-Hydroxychromones (3HC), exhibit dual emissions highly sensitive to solvent properties due to excited state intramolecular proton transfer (ESIPT). Therefore, 3HCs find wide applications as fluorescence probes in biological systems. Here, it is particularly important to understand the fluorescence behaviour of 3HCs in polar environments. Herein, we studied 3-hydroxyflavone, 2-(2-furyl)-3-hydroxychromone and 2-(2-benzofuryl)-3-hydroxychromone in high polarity solvents characterized by different H-bond donor abilities, donor concentrations and acceptor abilities. Our results show that the dual emissions of the dyes are insensitive to solvent basicity but strongly depend on the two other parameters. Moreover, furyl- and benzofuryl-substituted dyes were significantly more sensitive than the 3-hydroxyflavone to H-bond donor ability, while all three dyes showed roughly equivalent high sensitivity to H-bond donor concentration. These results can be explained by different mechanisms. Thus, the sensitivity of all three dyes to increasing concentrations of H-bond donors probably results from increase in the population of solvated dye with disrupted intramolecular H-bonds. Meantime, the sensitivity to Hbond donor ability of the solvent, observed mainly with furyl and benzofuryl dyes, is probably related to the strength of the H-bonds between the solvent and the 4-carbonyl group of the dye with intact intramolecular H-bonds. The present results provide new insights for further applications of 3HC derivatives as environment-sensitive probes and labels of biological molecules.

  7. Solvent effects on the morphology and performance of the anode substrates for solid oxide fuel cells

    Science.gov (United States)

    Liu, Tong; Ren, Cong; Zhang, Yanxiang; Wang, Yao; Lei, Libin; Chen, Fanglin

    2017-09-01

    Solvents effects on the microstructure of anode substrates as well as the electrochemical performance of the respective cells are systematically evaluated. The solubility parameters are used to interpret the relationship between the rheological properties of phase inversion slurries and pore formation mechanism of the anode substrates. When N-methyl-2-pyrrolidone (NMP) is chosen as the solvent, a dual-layered anode substrates with hierarchically oriented pores is achieved, while a sponge-like homogeneous anode substrate is obtained using dimethyl sulfoxide (DMSO) as the solvent, indicating that solvent is a key factor to affect the anode substrate microstructure. Two-dimensional and three-dimensional microstructures of the anode substrates prepared using NMP are analyzed by scanning electron microscopy and X-ray microscopy, respectively. Solid oxide fuel cells (SOFCs) with different microstructured anode substrates are prepared, and the maximum power density is significantly enhanced from 320.3 to 719.2 mWcm-2 by varying the anode substrate from homogeneous sponge-like microstructure to dual-layered microstructure, revealing that the finger-like macro-voids layer can facilitate H2-H2O mass diffusion, while the thin sponge-like pores layer can serve as anode functional layer and provide sufficient active reaction sites for H2 oxidation. This study demonstrates that NMP is a promising solvent to fabricate hierarchically oriented anode for high-performance SOFCs application.

  8. Nano-structured gemini-based supramolecular solvent for the microextraction of cyhalothrin and fenvalerate.

    Science.gov (United States)

    Feizi, Neda; Yamini, Yadollah; Moradi, Morteza; Ebrahimpour, Behnam

    2016-09-01

    A novel supramolecular solvent-based microextraction followed by high-performance liquid chromatography with ultraviolet detection method has been developed for the extraction and determination of two pyrethroid analytes, cyhalothrin and fenvalerate, in water and soil samples. The liquid-liquid-phase separation of surfactants has been used in analytical extraction. The surfactant-rich phase is a nano-structured liquid, recently named as a supramolecular solvent, generated from the amphiphiles. The alkyl carboxylic acid based supramolecular solvents were introduced before. Coacervates made up of gemini surfactant, consisting of two amphiphilic moieties, were first used as solvent. The effective parameters on extraction (i.e., type of organic solvent, the amount of surfactant and volume of tetrahydrofuran, sample solution pH, salt addition, ultrasonic and centrifugation time) were investigated and optimized. Under the optimum conditions, preconcentration factors of 110 and 145 were obtained for the analytes. The linearity was 0.5-200.0 μg/L with the correlation of determination of (R(2) ) ≥ 0.9984. The limit of detection of the method was (S/N = 3) 0.2 μg/L, and precisions in the range of 6.3-10.3% (RSDs, n = 5) were obtained. This method has been successfully applied to analyze real samples, and good recoveries in the range of 101.2-108.8% were obtained.

  9. Extraction of Illegal Dyes from Red Chili Peppers with Cholinium-Based Deep Eutectic Solvents.

    Science.gov (United States)

    Zhu, Shuqiang; Liu, Dongling; Zhu, Xinyue; Su, Along; Zhang, Haixia

    2017-01-01

    Deep eutectic solvents (DESs) as a new kind of green solvents have been used to extract bioactive compounds but there are few applications in extracting chrysoidine dyes. In this study, we developed an ultrasonic-assisted extraction method with choline chloride/hydrogen bond donor (ChCl/HBD) DES for the extraction of chrysoidine G (COG), astrazon orange G (AOG), and astrazon orange R (AOR) in food samples. Some experimental parameters, such as extraction time, raw material/solvent ratio, and temperature, were evaluated and optimized as follows: the ratio of ChCl/HBD, 1 : 2 (v/v); the ratio of sample/DES, 1 : 10 (g/mL); extraction time, 20 min; extraction temperature, 50°C. Under the optimized conditions, the limits of detection (μg/mL) were 0.10 for COG and 0.06 for AOG and AOR. The relative standard deviations were in the range of 1.2-2.1%. The recoveries of the three dyes were in the range of 80.2-105.0%. By comparing with other commonly used solvents for extracting chrysoidine dyes, the advantages of DESs proved them to be potential extraction solvents for chrysoidine G, astrazon orange G, and astrazon orange R in foods.

  10. Extraction of Illegal Dyes from Red Chili Peppers with Cholinium-Based Deep Eutectic Solvents

    Directory of Open Access Journals (Sweden)

    Shuqiang Zhu

    2017-01-01

    Full Text Available Deep eutectic solvents (DESs as a new kind of green solvents have been used to extract bioactive compounds but there are few applications in extracting chrysoidine dyes. In this study, we developed an ultrasonic-assisted extraction method with choline chloride/hydrogen bond donor (ChCl/HBD DES for the extraction of chrysoidine G (COG, astrazon orange G (AOG, and astrazon orange R (AOR in food samples. Some experimental parameters, such as extraction time, raw material/solvent ratio, and temperature, were evaluated and optimized as follows: the ratio of ChCl/HBD, 1 : 2 (v/v; the ratio of sample/DES, 1 : 10 (g/mL; extraction time, 20 min; extraction temperature, 50°C. Under the optimized conditions, the limits of detection (μg/mL were 0.10 for COG and 0.06 for AOG and AOR. The relative standard deviations were in the range of 1.2–2.1%. The recoveries of the three dyes were in the range of 80.2–105.0%. By comparing with other commonly used solvents for extracting chrysoidine dyes, the advantages of DESs proved them to be potential extraction solvents for chrysoidine G, astrazon orange G, and astrazon orange R in foods.

  11. Comparison of solvent mixtures for pressurized solvent extraction of soil fatty acid biomarkers.

    Science.gov (United States)

    Jeannotte, Richard; Hamel, Chantal; Jabaji, Suha; Whalen, Joann K

    2008-10-19

    The extraction and transesterification of soil lipids into fatty acid methyl esters (FAMEs) is a useful technique for studying soil microbial communities. The objective of this study was to find the best solvent mixture to extract soil lipids with a pressurized solvent extractor system. Four solvent mixtures were selected for testing: chloroform:methanol:phosphate buffer (1:2:0.8, v/v/v), chloroform:methanol (1:2, v/v), hexane:2-propanol (3:2, v/v) and acetone. Soils were from agricultural fields and had a wide range of clay, organic matter and microbial biomass contents. Total lipid fatty acid methyl esters (TL-FAMEs) were the extractable soil lipids identified and quantified with gas chromatography and flame ionization detection. Concentrations of TL-FAMEs ranged from 57.3 to 542.2 nmole g(-1) soil (dry weight basis). The highest concentrations of TL-FAMEs were extracted with chloroform:methanol:buffer or chloroform:methanol mixtures than with the hexane:2-propanol or acetone solvents. The concentrations of TL-FAMEs in chemical groups, including saturated, branched, mono- and poly-unsaturated and hydroxy fatty acids were assessed, and biological groups (soil bacteria, mycorrhizal fungi, saprophytic fungi and higher plants) was distinguished. The extraction efficiency for the chemical and biological groups followed the general trend of: chloroform:methanol:buffer> or =chloroform:methanol>hexane:2-propanol=acetone. Discriminant analysis revealed differences in TL-FAME profiles based on the solvent mixture and the soil type. Although solvent mixtures containing chloroform and methanol were the most efficient for extracting lipids from the agricultural soils in this study, soil properties and the lipid groups to be studied should be considered when selecting a solvent mixture. According to our knowledge, this is the first report of soil lipid extraction with hexane:2-propanol or acetone in a pressurized solvent extraction system.

  12. Biodiesel production from ethanolysis of palm oil using deep eutectic solvent (DES) as co-solvent

    Science.gov (United States)

    Manurung, R.; Winarta, A.; Taslim; Indra, L.

    2017-06-01

    Biodiesel produced from ethanolysis is more renewable and have better properties (higher oxidation stability, lower cloud and pour point) compared to methanolysis, but it has a disadvantage such as complicated purification. To improve ethanolysis process, deep eutectic solvent (DES) can be prepared from choline chloride and glycerol and used as co-solvent in ethanolysis. The deep eutectic solvent is formed from a quaternary ammonium salt (choline chloride) and a hydrogen bond donor (Glycerol), it is a non-toxic, biodegradable solvent compared to a conventional volatile organic solvent such as hexane. The deep eutectic solvent is prepared by mixing choline chloride and glycerol with molar ratio 1:2 at temperature 80 °C, stirring speed 300 rpm for 1 hour. The DES is characterized by its density and viscosity. The ethanolysis is performed at a reaction temperature of 70 °C, ethanol to oil molar ratio of 9:1, potassium hydroxide as catalyst concentration of 1.2 wt. DES as co-solvent with concentration 0.5 to 3 wt. stirring speed 400 rpm, and a reaction time 1 hour. The obtained biodiesel is then characterized by its density, viscosity, and ester content. The oil - ethanol phase condition is observed in the reaction tube. The oil - ethanol phase with DES tends to form meniscus compared to without DES, showed that oil and ethanol become more slightly miscible, which favors the reaction. Using DES as co-solvent in ethanolysis showed increasing in yield and easier purification. The esters properties meet the international standards ASTM D6751, with the highest yield achieved 83,67 with 99,77 conversion at DES concentration 2 . Increasing DES concentration above 2 in ethanolysis decrease the conversion and yield, because of the excessive glycerol in the systems makes the reaction equilibrium moves to the reactant side.

  13. Isolation of all-trans lycopene by high-speed counter-current chromatography using a temperature-controlled solvent system.

    Science.gov (United States)

    Baldermann, Susanne; Ropeter, Katharina; Köhler, Nils; Fleischmann, Peter

    2008-05-23

    The effect of solvent system, partition coefficient, retention of stationary phase, column, revolution speed, and flow rate of mobile phase are well known parameters to effect HSCCC (high-speed counter-current chromatography) separations. Temperature effects on chromatographic techniques like HPLC and GC are well studied, but the influence of temperature on CCC solvent systems is hardly investigated. This paper presents the influence of temperature on several key parameters (partition coefficient, settling time, volume ratios) in the hydrophobic HSCCC solvent system hexane:dichloromethane:acetonitrile (30:11:18, v/v/v) used for the isolation of lycopene from tomato paste at 10, 15, 20 and 25 degrees C.

  14. Relative ototoxicity of 21 aromatic solvents

    Energy Technology Data Exchange (ETDEWEB)

    Gagnaire, Francois; Langlais, Cristina [Institut National de Recherche et de Securite, Departement Polluants et Sante, Vandoeuvre (France)

    2005-06-01

    Some aromatic solvents (e.g. toluene, p-xylene, styrene, and ethylbenzene) show, in the rat, striking ototoxicity characterized by an irreversible hearing loss, as measured by behavioural or electrophysiological methods, associated with damage to outer hair cells in the cochlea of the exposed animals. To broaden the range of aromatic solvents studied concerning their potential ototoxicity and to compare their ototoxicity quantitatively, 21 aromatic solvents were administered orally by gastric intubation to Sprague-Dawley rats for 5 days/week for a 2-week period. The dose used was 8.47 mmol kg{sup -1} body weight day{sup -1}. The possible ototoxicity of the aromatic solvents was evaluated by morphological investigation of the cochlea. Whole-mount surface preparations of the organ of Corti were made to quantify the number of missing hair cells (cytocochleogram). Among the 21 solvents studied, eight (toluene, p-xylene, ethylbenzene, n-propylbenzene, styrene, {alpha}-methylstyrene, trans-{beta}-methylstyrene, and allylbenzene) caused histological lesions of the organ of Corti. They differed widely in their potency. The least ototoxic solvents caused outer hair cell (OHC) loss in the middle turn of the organ of Corti. The OHC loss was slight in the first row, and greater in the second and third rows. The most ototoxic solvents caused high losses in the three rows of the outer hair cells along the entire length of the basilar membrane. There were also occasional inner hair cell (ICH) losses in the most affected animals. Although no measurements were made of the chemical concentrations reached in the blood or the brain, tentative ranking of an increasing ototoxicity of the eight aromatic solvents could be proposed on the basis of the histological losses observed - {alpha}-methylstyrene

  15. Glassy protein dynamics and gigantic solvent reorganization energy of plastocyanin

    CERN Document Server

    LeBard, David N

    2007-01-01

    We report the results of Molecular Dynamics simulations of electron transfer activation parameters of plastocyanin metalloprotein involved as electron carrier in natural photosynthesis. We have discovered that slow, non-ergodic conformational fluctuations of the protein, coupled to hydrating water, result in a very broad distribution of donor-acceptor energy gaps far exceeding that observed for commonly studied inorganic and organic donor-acceptor complexes. The Stokes shift is not affected by these fluctuations and can be calculated from solvation models in terms of the response of the solvent dipolar polarization. The non-ergodic character of large-amplitude protein/water mobility breaks the strong link between the Stokes shift and reorganization energy characteristic of equilibrium (ergodic) theories of electron transfer. This mechanism might be responsible for low activation barriers in natural electron transfer proteins characterized by low reaction free energy.

  16. Lysozyme gelation in mixtures of tetramethylurea with protic solvents: Use of solvatochromic indicators to probe medium microstructure and solute solvent interactions

    Science.gov (United States)

    da Silva, Marcelo A.; El Seoud, Omar A.; Arêas, Elizabeth P. G.

    2007-09-01

    This work investigated the relationship between the structure of binary mixtures of tetramethylurea and protic solvents and their capacity to induce lysozyme gelation. In order to get an insight into the mechanism of gel formation, the solvatochromic behavior of zwitterionic probes, employed as simple models for the protein, was investigated. We studied two probes of similar p Ka's, but different hydrophobic character, namely 2,6-diphenyl-4-(2,4,6-triphenylpyridinium-1-yl) phenolate, RB, and 4-[2-(1-methylpyridinium-4-yl) ethenyl] phenolate, MC. The protic solvents used included water, 1-propanol and 2- n-butoxyethanol in the temperature range from 10 to 60 °C, and methanol, from 10 to 40 °C. In all cases, the dependence of the empirical solvent polarity parameter, ET, on mixture composition was non-ideal with negative deviation for TMU-water and positive deviation for TMU-organic solvent. For all binary mixtures, the deviation from linearity decreased as a function of increasing the temperature. In TMU/alcohol, the effect became more pronounced with increasing alcohol hydrophobicity.

  17. 29 CFR 1915.32 - Toxic cleaning solvents.

    Science.gov (United States)

    2010-07-01

    ... Preservation § 1915.32 Toxic cleaning solvents. (a) When toxic solvents are used, the employer shall employ one... space. (2) Either natural ventilation or mechanical exhaust ventilation shall be used to remove the...

  18. Organic Solvent Tropical Report [SEC 1 and 2

    Energy Technology Data Exchange (ETDEWEB)

    COWLEY, W.L.

    2000-06-21

    This report provides the basis for closing the organic solvent safety issue. Sufficient information is presented to conclude that risk posed by an unmitigated organic solvent fire is within risk evaluation guidelines.

  19. Selection and evaluation of alternative solvents for caprolactam extraction

    NARCIS (Netherlands)

    Delden, van Mathijs L.; Kuipers, Norbert J.M.; Haan, de André B.

    2006-01-01

    Because of the strict legislation for currently applied solvents in the industrial extraction of caprolactam, being benzene, toluene and chlorinated hydrocarbons, a need exists for alternative, environmentally benign solvents. An experimental screening procedure consisting of several steps was used

  20. Occupational exposure to chlorinated and petroleum solvents and mycosis fungoides

    DEFF Research Database (Denmark)

    Morales-Suárez-Varela, Maria M; Olsen, Jørn; Villeneuve, Sara

    2013-01-01

    To evaluate the potential association between occupational exposure to chlorinated and petroleum solvents and mycosis fungoides (MF).......To evaluate the potential association between occupational exposure to chlorinated and petroleum solvents and mycosis fungoides (MF)....

  1. The Ideal Solvent for Paper Chromatography of Food Dyes.

    Science.gov (United States)

    Markow, Peter G.

    1988-01-01

    Uses paper chromatography with food dyes to provide a simple and inexpensive basis for teaching chromatography. Provides experimental methodology and tabled results. Includes a solvent system comparison (Rf) for seven dyes and twenty-two solvents. (MVL)

  2. Effect of solvents on propylene epoxidation over TS-1 catalyst

    Institute of Scientific and Technical Information of China (English)

    Yulong WU; Qingshan LIU; Xueli SU; Zhentao MI

    2008-01-01

    Solvents have an important effect on the epoxidation of propylene catalyzed by TS-1. The experimental results show that, in different solvents, the catalytic activity of epoxidation is in the following order: methanol > 2-propanol > 2-butanol > acetoni-trile > acetone > tetrahydrofuran. Based on the reaction mechanism, the effects of solvents on the epoxidation were studied from eight aspects, which included the electronic effect, the steric effect, the polarity of solvent, the effect of solvent on sorption and diffusion of reactant, the oxidation of alcohol, the etherification of PO, the deactivation of TS-1 and the solubility of propylene in the solvents. The electronic effect, steric effect and the polarity of solvent were considered to be the main aspects. This work may provide theoretical guidance for choosing solvents for these kinds of reactions and also may serve as basis for further industrialization.

  3. A solvent/non-solvent system for achieving solution-processed multilayer organic light-emitting devices

    Energy Technology Data Exchange (ETDEWEB)

    Yu, Yue; Wu, Zhaoxin, E-mail: zhaoxinwu@mail.xjtu.edu.cn; He, Lin; Jiao, Bo; Hou, Xun

    2015-08-31

    We developed a solvent/non-solvent system to fabricate the multilayer organic light-emitting devices (OLEDs) based on poly(N-vinylcarbazole) (PVK) by solution-process. This solvent system consists of both the solvent and non-solvent of PVK, in which fluorescent small molecules could be fully dissolved and directly spin-coated on top of the PVK layer; it could effectively avoid the redissolution of PVK during the spin-coating process of small molecules emitting layer. In the further investigation of this system, we also demonstrated the three-component solvent system, and found out that the third component, a less volatile solvent of PVK, was crucial for preparing a smoother interface between PVK and emitting layer. Compared with OLEDs through the vacuum deposition, the devices fabricated by solution-process from the solvent/non-solvent system showed comparable efficiency, which indicate that the solvent/non-solvent system can be used as an alternative process to prepare the polymer and small molecule multilayer devices through all-solution-process. - Highlights: • We fabricate the multilayer OLEDs by solution-process using a novel system. • We develop a solvent/non-solvent system of polymer (PVK) to avoid redissolution. • Small molecules could be fully dissolved and directly spin-coated on PVK layer. • The devices fabricated by the system and vacuum deposition show comparable efficiency.

  4. Solid-Liquid Equilibria of Succinic Acid in Cyclohexanone, Cyclohexanol and Their Mixed Solvents

    Institute of Scientific and Technical Information of China (English)

    FAN Lihua; MA Peisheng; SONG Weiwei

    2007-01-01

    Solubilities were measured for succinic acid dissolved in cyclohexanone, cyclohexanol and 5 of their mixed solvents at the temperature range from 291.85 K to 358.37 K using a dynamic method. The solubility data were regressed by λh equation, withthe average absolute relative deviation 3.47%. The binary interaction parameter is 0.306 7 for the mixed solvent of cyclohexanone and cyclohexanol was determined by correlating the experimental solubilities with the modified λh equation. When the binary interaction parameter was determined, it can be used to extrapolate the solubilities of succinic acid in mixed solvents of cyclohexanone and cyclohexanol at any proportion. The average absolute relative deviation was 7.69% by using the modified λh equation to correlate the solubility data, however, the average absolute relative deviation was 8.89% by using NRTL equation to correlate the solubility data. The results show that the accuracy of the modified λh equation is better than that of the NRTL equation for the solubility of succinic acid in the 5 mixed solvents of cyclohexanone and cyclohexanol.

  5. VISCOMETRIC INVESTIGATIONS OF POLYVINYLPYRROLIDONE IN MIXED SOLVENTS AND WITH VARYING TEMPERATURE

    Institute of Scientific and Technical Information of China (English)

    Omar Melad; Omar Abu-Tiem; Rajai Baraka

    2005-01-01

    The viscosity behavior of polyvinylpyrrolidone (PVP) has been determined at 25℃ in mixed solvents comprising water/dimethylformamide (DMF) and water /methanol (MeOH). Analysis of the data has considered the PVP as being both host and guest polymer in solution. The intrinsic viscosity of PVP in DMF is higher than in water and in MeOH, but also increases in a mixed solvent with high water content because of the effect of polymer-solvent interactions. It was also found that the intrinsic viscosity of PVP at finite concentration, [ηPVP]c decreases with an increase in the concentration of PVP in solution. The viscosity behavior of PVP in a mixed solvent is affected by the concentration-dependent intermolecular excluded volume effect, which can be quantitatively expressed by the parameter, bY, which reflects the shrinkage of PVP chain coils, resulting in a decrease of [ηPVP]c . The effect of temperature on the viscosity behavior of PVP in MeOH shows that the interaction parameter increases up to a maximum value, and then decreases after a certain temperature.

  6. Aggregation behavior modulation of 1-dodecyl-3-methylimidazolium bromide by organic solvents in aqueous solution.

    Science.gov (United States)

    Wang, Jianji; Zhang, Lamei; Wang, Huiyong; Wu, Changzeng

    2011-05-05

    Material preparation in ionic liquids and environmental pollution control by ionic liquids are often closely dependent on the aggregation behavior of ionic liquids in solution. In the present work, conductivity, fluorescence probe, and dynamic light scattering techniques have been used to study the effect of organic solvents on the aggregation behavior of 1-dodecyl-3-methylimidazolium bromide in water. It was shown that the critical aggregation concentration (CAC), the ionization degree of the aggregates (α), and the standard Gibbs energy of aggregation (ΔG(m)°) of the ionic liquid increase, while its aggregation number (N(agg)) and aggregates' size decrease with increasing concentration of organic additives in water. These results have been discussed from the favorable interactions of alkyl chain of the ionic liquid with the mixed solvents. It is suggested that the solvophobic parameter, characterized quantitatively by Gibbs energy of transfer of hydrocarbon from gas into a given solvent, can be used to account for the effect of organic additives on the formation and growth of the ionic liquid aggregates in water. Aggregation behavior of ionic liquids in aqueous organic solutions can be modulated simply by the solvophobic parameters of hydrocarbon in the mixed solvents.

  7. Solvent empirical scales and their importance for the study of intermolecular interactions

    Science.gov (United States)

    Babusca, Daniela; Benchea, Andreea Celia; Morosanu, Ana Cezarina; Dimitriu, Dan Gheorghe; Dorohoi, Dana Ortansa

    2017-01-01

    The solvent empirical scales were developed in order to classify the solvents regarding their influence on the absorption or fluorescence spectra of different spectrally active molecules. The intermolecular interactions in binary solutions of three molecule having an intramolecular charge transfer visible absorption band are studied in this paper: 5-[2-(1,2,2,4-tetramethyl-1,2,3,4-tetrahydroquinolin-6-yl)-vinyl]-thiophene-2-carbaldehyde (QTC), 1-cyano-2-{5-[2-(1,2,2,4-tetramethyl-1,2,3,4-tetrahydroquinolin-6-yl)-vinyl]-thiophen-2-yl}-vinyl)-phosphonic acid diethyl ester (QTCP) and p-phenyl pyridazinium-p-nitro-phenacylid (PPNP). The solvent empirical scales with a single parameter (Z scale of Kosower, ET (30) or ETN scale of Reichardt and Dimroth) can be used to describe the strength of intermolecular interactions. The contributions of each type of interactions to the total spectral shift are evaluated using the solvent multiple parameters empirical scales defined by Kamlet and Taft and by Catalan et al.

  8. (Liquid + liquid) equilibria in ternary aqueous mixtures of phosphoric acid with organic solvents at T = 298.2 K

    Energy Technology Data Exchange (ETDEWEB)

    Ghanadzadeh, H., E-mail: hggilani@guilan.ac.i [Department of Chemistry, Faculty of Science, University of Guilan, Rasht (Iran, Islamic Republic of); Department of Chemical Engineering, University of Guilan, Rasht (Iran, Islamic Republic of); Ghanadzadeh, A., E-mail: aggilani@guilan.ac.i [Department of Chemistry, Faculty of Science, University of Guilan, Rasht (Iran, Islamic Republic of); Aghajani, Z.; Abbasnejad, S.; Shekarsaraee, S. [Department of Chemistry, Faculty of Science, University of Guilan, Rasht (Iran, Islamic Republic of)

    2010-06-15

    (Liquid + liquid) equilibrium (LLE) data for the ternary mixtures of left bracewater (1) + phosphoric acid (2) + organic solvents (3)right brace were determined at T = 298.2 K and atmospheric pressure. The organic solvents were cyclohexane, 2-methyl-2-butanol (tert-amyl alcohol), and isobutyl acetate. All the investigated systems exhibit Type-1 behaviour of LLE. The immiscibility region was found to be larger for the (water + phosphoric acid + cyclohexane) ternary system. The experimental LLE results were correlated with the NRTL model, and the binary interaction parameters were obtained. The reliability of the experimental tie-line results was tested through the Othmer-Tobias and Bachman correlation equations. Distribution coefficients and separation factors were evaluated over the immiscibility regions and a comparison of the extracting capabilities of the solvents was made with respect to these factors. The experimental results indicate the superiority of cyclohexane as the preferred solvent for the extraction of phosphoric acid from its aqueous solutions.

  9. Effect of Immerse Temperature and Time on Solvent Debinding Process of Stainless Steel 316L Metal Injection Molding

    Science.gov (United States)

    Hafizah Kamarudin, Nur; Irwan Ibrahim, Mohd Halim

    2017-01-01

    This study was carried out to investigate solvent debinding by conducting the extraction process at temperature ranging from 40 to 80 °C within 2 to 8 hours, while keeping the heptane solvent and 12:1 of solvent to feed ratio as constant. The palm kernel loss was evaluated as an indicator of the process’s performance. It was also supported by the pore evolution that was observed by Field Emission Scanning Electron Micrograph (FESEM). Results show that both parameter give large effect on the solvent debinding performance. The best immerse temperature and time for extracting maximum palm kernel in heptane solution at S/F ratio of 12:1, without sacrificing the ability of producing free defect metal part were given by 80 °C and 6 hours, respectively.

  10. NMR microscopy of tissue in organic and mixed solvents

    OpenAIRE

    Macura Slobodan; Mishra Prasanna K.; Gamez Jeffrey D.; Pirko Istvan

    2013-01-01

    We propose to use organic and mixed solvents for nuclear magnetic resonance microscopy of fixed tissue as a means for improving image information content. NMR properties of some standard solvents (methanol, acetone, DMSO) and solvents in use for tissue processing in pathology (xylenes, paraffin, ‘Clearify’) have been measured, reviewed, and analyzed. It was found that DMSO and paraffin are very useful solvents that provide images of better quality than thos...

  11. Functionalization of graphene using deep eutectic solvents

    Science.gov (United States)

    Hayyan, Maan; Abo-Hamad, Ali; AlSaadi, Mohammed AbdulHakim; Hashim, Mohd Ali

    2015-08-01

    Deep eutectic solvents (DESs) have received attention in various applications because of their distinctive properties. In this work, DESs were used as functionalizing agents for graphene due to their potential to introduce new functional groups and cause other surface modifications. Eighteen different types of ammonium- and phosphonium-salt-based DESs were prepared and characterized by FTIR. The graphene was characterized by FTIR, STA, Raman spectroscopy, XRD, SEM, and TEM. Additional experiments were performed to study the dispersion behavior of the functionalized graphene in different solvents. The DESs exhibited both reduction and functionalization effects on DES-treated graphene. Dispersion stability was investigated and then characterized by UV-vis spectroscopy and zeta potential. DES-modified graphene can be used in many applications, such as drug delivery, wastewater treatment, catalysts, composite materials, nanofluids, and biosensors. To the best of our knowledge, this is the first investigation on the use of DESs for graphene functionalization.

  12. Alternative solvents for post combustion carbon capture

    Directory of Open Access Journals (Sweden)

    Udara S. P. R. Arachchige, Morten C. Melaaen

    2013-01-01

    Full Text Available The process model of post combustion chemical absorption is developed in Aspen Plus for both coal and gas fired power plant flue gas treating. The re-boiler energy requirement is considered as the most important factor to be optimized. Two types of solvents, mono-ethylamine (MEA and di-ethylamine (DEA, are used to implement the model for three different efficiencies. The re-boiler energy requirement for regeneration process is calculated. Temperature and concentration profiles in absorption column are analyzed to understand the model behavior. Re-boiler energy requirement is considerably lower for DEA than MEA as well as impact of corrosion also less in DEA. Therefore, DEA can be recommended as a better solvent for post combustion process for carbon capture plants in fossil fuel fired power industries.

  13. Myoglobin solvent structure at different temperatures

    Energy Technology Data Exchange (ETDEWEB)

    Daniels, B.V.; Korszun, Z.R. [Brookhaven National Laboratory, Upton, NY (United States); Schoenborn, B.P. [Los Alamos National Laboratory, NM (United States)

    1994-12-31

    The structure of the solvent surrounding myoglobin crystals has been analyzed using neutron diffraction data, and the results indicate that the water around the protein is not disordered, but rather lies in well-defined hydration shells. We have analyzed the structure of the solvent surrounding the protein by collecting neutron diffraction data at four different temperatures, namely, 80, 130, 180, and 240K. Relative Wilson Statistics applied to low resolution data showed evidence of a phase transition in the region of 180K. A plot of the liquidity factor, B{sub sn}, versus distance from the protein surface begins with a high plateau near the surface of the protein and drops to two minima at distances from the protein surface of about 2.35{Angstrom} and 3.85{Angstrom}. Two distinct hydration shells are observed. Both hydration shells are observed to expand as the temperature is increased.

  14. Critical bubble radius in solvent sublation

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    The complex compound of dithizone-Co(Ⅱ) was separated and concentrated from the aqueous phase to n-octanol by solvent sublation. From the analysis of the coalescence behavior of bubbles on water-organic interface, the conception of critical bubble radius was proposed, and the value of the critical bubble radius in the water-octanol system was obtained: 1.196 × 10-3 m. The simulation of the mathematical model using CBR and experimental data is completed with perfect results, and the simulation of the mathematical model using CBR is very different with the classic one. The analytical results proved that the critical bubble radius should be adequately considered in mathematical model of solvent sublation.

  15. High performance hydrophobic solvent, carbon dioxide capture

    Energy Technology Data Exchange (ETDEWEB)

    Nulwala, Hunaid; Luebke, David

    2017-05-09

    Methods and compositions useful, for example, for physical solvent carbon capture. A method comprising: contacting at least one first composition comprising carbon dioxide with at least one second composition to at least partially dissolve the carbon dioxide of the first composition in the second composition, wherein the second composition comprises at least one siloxane compound which is covalently modified with at least one non-siloxane group comprising at least one heteroatom. Polydimethylsiloxane (PDMS) materials and ethylene-glycol based materials have high carbon dioxide solubility but suffer from various problems. PDMS is hydrophobic but suffers from low selectivity. Ethylene-glycol based systems have good solubility and selectivity, but suffer from high affinity to water. Solvents were developed which keep the desired combinations of properties, and result in a simplified, overall process for carbon dioxide removal from a mixed gas stream.

  16. Alternative solvents for post combustion carbon capture

    Energy Technology Data Exchange (ETDEWEB)

    Arachchige, Udara S.P.R. [Telemark University College, Porsgrunn (Norway); Melaaen, Morten C. [Telemark University College, Porsgrunn (Norway); Tel-Tek, Porsgrunn (Norway)

    2013-07-01

    The process model of post combustion chemical absorption is developed in Aspen Plus for both coal and gas fired power plant flue gas treating. The re-boiler energy requirement is considered as the most important factor to be optimized. Two types of solvents, mono-ethylamine (MEA) and di-ethylamine (DEA), are used to implement the model for three different efficiencies. The re-boiler energy requirement for regeneration process is calculated. Temperature and concentration profiles in absorption column are analyzed to understand the model behavior. Re-boiler energy requirement is considerably lower for DEA than MEA as well as impact of corrosion also less in DEA. Therefore, DEA can be recommended as a better solvent for post combustion process for carbon capture plants in fossil fuel fired power industries.

  17. Effect of water droplet in solvent sublation

    Institute of Scientific and Technical Information of China (English)

    Peng Yu Bi; Hui Ru Dong; Nan Nan Wang

    2008-01-01

    Aqueous phase layer around bubble and water droplet are two additional processes in solvent sublation. In the dynamic processof mass transfer, they are always neglected, but they are very important in the investigation of thermodynamic equilibrium. In thispaper, the effect of water droplet in solvent sublation was discussed in detail, and the previous mathematical model of solventsubaltion was improved. Matlab 6.5 was used to simulate the process of water droplets, and the comparison between the previoushypothesis and the improvement in this paper showed the superiority, especially in the investigation of thermodynamic equilibrium.Moreover, the separation and concentration of the complex compound dithizone-Co(Ⅱ) from aqueous phase to n-octanol by solventsublation also proved the improved mathematical model was reasonable.2008 Hui Ru Dong. Published by Elsevier B.V. on behalf of Chinese Chemical Society. All rights reserved.

  18. Development of a solvent processed insensitive propellant

    Science.gov (United States)

    Trask, R.; Costa, E.; Beardell, A. J.

    1980-01-01

    Two types of low vulnerability propellants are studied which are distinguished by whether the binder is a rubber, such as polyurethane or CTBN, or a plasticizable polymer such as ethyl cellulose or cellulose acetate. The former propellants are made by a partial cure extrusion process while the latter are made by the conventional solvent process. Emphasis is given to a cellulose binder (plasticizer) RDX composition. The type of binder used, the particle size of the RDX and the presence of small quantities of nitrocellulose in the solvent processed compositions have important influences on the mechanical and combustion characteristics of the propellant. The low temperature combustion is of particular concern because of potential breakup of the grains that can lead to instability.

  19. Solvent extraction of Southern US tar sands

    Energy Technology Data Exchange (ETDEWEB)

    Penney, W.R.

    1990-01-01

    The Department of Chemical Engineering at the University of Arkansas, in association with Diversified Petroleum Recovery, Inc. (DPR) of Little Rock, Arkansas, has been developing a solvent extraction process for the recovery of bitumen from tar sands for the past five years. The unique feature of the process is that the bitumen is recovered from the solvent by contacting with a co-solvent, which causes the bitumen to precipitate. The overall purpose of this project is to study both the technical and economic feasibility of applying this technology for recovery of bitumen from tar sands by (1) investigating the socioeconmic factors which affect (a) plant siting and (b) the market value of recovered bitumen; (2) operating a process demonstration unit at the rate of 1 lb/hr recovered bitumen while producing clean sand and recyclable solvents; and (3) determine the economic conditions which will make a bitumen recovery project economical. DPR has analyzed the historical trends of domestic production, consumption, discoveries and reserves of crude oil. They have started an investigation of the volatility in the price of crude oil and of gasoline prices and of the differential between gasoline and crude oil. DPR continues to analyze the geographical movement and demand for asphalt products. Utah does not appear economically attractive as a site for a bitumen from tar sands asphalt plant. Oklahoma sites are now being studied. This report also contains the quarterly progress report from a University of Nevada study to determine bitumen composition, oxygen uptake rates, and viscosities of Alabama and Utah bitumens. Both reports have been indexed separately for inclusion on the data base.

  20. Solvent extraction of Southern US tar sands

    Energy Technology Data Exchange (ETDEWEB)

    Penney, W.R.

    1990-01-01

    The Department of Chemical Engineering at the University of Arkansas, in association with Diversified Petroleum Recovery, Inc. (DPR) of Little Rock, Arkansas, has been developing a solvent extraction process for the recovery of bitumen from tar sands for the past five years. The unique feature of the process is that the bitumen is recovered from the solvent by contacting with a co-solvent, which causes the bitumen to precipitate. The overall purpose of this project is to study both the technical and economic feasibility of applying this technology for recovery of bitumen from tar sands by (1) investigating the socioeconmic factors which affect (a) plant siting and (b) the market value of recovered bitumen; (2) operating a process demonstration unit at the rate of 1 lb/hr recovered bitumen while producing clean sand and recyclable solvents; and (3) determine the economic conditions which will make a bitumen recovery project economical. DPR has analyzed the historical trends of domestic production, consumption, discoveries and reserves of crude oil. They have started an investigation of the volatility in the price of crude oil and of gasoline prices and of the differential between gasoline and crude oil. DPR continues to analyze the geographical movement and demand for asphalt products. Utah does not appear economically attractive as a site for a bitumen from tar sands asphalt plant. Oklahoma sites are now being studied. This report also contains the quarterly progress report from a University of Nevada study to determine bitumen composition, oxygen uptake rates, and viscosities of Alabama and Utah bitumens. Both reports have been indexed separately for inclusion on the data base.

  1. Solvent Retention Capacities of Oat Flour

    Directory of Open Access Journals (Sweden)

    Qianwen Niu

    2017-03-01

    Full Text Available This study measured the solvent retention capacities (SRCs of flours from eight oat varieties and one wheat variety against different solvents to explore the swelling volume of oat flour with different solvents, and thus provide a theoretical basis for quick β-glucan analysis. The SRC profile consists of water SRC (WSRC, 50% sucrose SRC (SSRC, 5% lactic acid SRC (LASRC, 5% Na2CO3 SRC (SCASRC, NaCl SRC (SCSRC, CaCl2 SRC (CCSRC, FeCl3 SRC (FCSRC, sodium cholate SRC (SCHSRC, NaOH (pH 10 SRC (SHSRC, Na2CO3 (pH 10 SRC (SCABSRC and SDS (pH 10 SRC (SDSSRC values, and a Chopin SRC kit was used to measure the SRC value. SRCs of the oat flours increased when the solvents turned from neutral (water and NaCl to acidic (5% lactic acid or alkaline (5% Na2CO3, CaCl2, FeCl3, NaOH and pH 10 Na2CO3, and rose as the metal ion valencies of the metal salts (NaCl, CaCl2 and FeCl3 increased. The β-glucan contents were significantly positively correlated with the SCSRC (0.83**, CCSRC (0.82**, SCHSRC (0.80** and FCSRC (0.78*. SRC measurements of β-glucan in oat flours revealed that the CCSRC values were related with β-glucan (0.64* but not related with protein and starch. CaCl2 could therefore potentially be exploited as a reagent for β-glucan assay.

  2. Indentation of polydimethylsiloxane submerged in organic solvents

    OpenAIRE

    Hu, Yuhang; Chen, Xin; Whitesides, George McClelland; Vlassak, Joost J.; Suo, Zhigang

    2011-01-01

    This work uses a method based on indentation to characterize a polydimethylsiloxane (PDMS) elastomer submerged in an organic solvent (decane, heptane, pentane, or cyclohexane). An indenter is pressed into a disk of a swollen elastomer to a fixed depth, and the force on the indenter is recorded as a function of time. By examining how the relaxation time scales with the radius of contact, one can differentiate the poroelastic behavior from the viscoelastic behavior. By matching the relaxation c...

  3. Coupling of protein dynamics with the solvent

    Science.gov (United States)

    Caliskan, Gokhan; Sauzan, Azzam; Mehtani, Disha; Sokolov, Alexei

    2003-03-01

    Glycerol and trehalose are among the many viscous solvents that are widely used for biostabilization and controlling the dynamics of proteins. It is believed that the suppression of the structural relaxations by high viscosity of solvent is responsible for improved stability in proteins. However, results of [1] and [2] demonstrate stronger suppression of biochemical activity and dynamics of proteins by liquid glycerol than by solid trehalose in a wide temperature range. The authors tried to explain the counterintuitive observations by a possible decoupling of the dynamics of the protein from trehalose. In order to test the validity of this assumption and to investigate the influence of the fast dynamics in proteins, the low frequency Raman scattering spectroscopy technique is used. Both relaxational and vibrational dynamics of glycerol, trehalose, and lysozyme in glycerol and in trehalose are studied in a wide temperature range. Dynamics of lysozyme in glycerol follows the strong temperature dependence of relaxational and vibrational dynamics of the bulk glycerol. On the other hand, the weak temperature dependence of dynamics of lysozyme in trehalose follows exactly the behavior of pure trehalose. This proves that there is a strong dynamic coupling between the protein and the solvents used. Interestingly, stronger relaxations in solid trehalose as compared to liquid glycerol are observed in the GHz region at low temperatures. This could be the reason for the enhanced protein activity observed in trehalose, compared to that in glycerol in this temperature range. Suppression of these fast relaxations should be the key for providing long-term stability to proteins. 1. Sastry, G.M. and N. Agmon, Trehalose prevents myoglobin collapse and preserves its internal mobility. BIOCHEMISTRY, 1997, 36(23): p. 7097-108. 2. Caliskan, G., et al., Influence of solvent on dynamics and stability of a protein. Journal of Non-Crystalline Solids, 2002, 307-310: p. 887-893.

  4. Solvent Retention Capacities of Oat Flour

    Science.gov (United States)

    Niu, Qianwen; Pu, Yu; Li, Xiaoping; Ma, Zhen; Hu, Xinzhong

    2017-01-01

    This study measured the solvent retention capacities (SRCs) of flours from eight oat varieties and one wheat variety against different solvents to explore the swelling volume of oat flour with different solvents, and thus provide a theoretical basis for quick β-glucan analysis. The SRC profile consists of water SRC (WSRC), 50% sucrose SRC (SSRC), 5% lactic acid SRC (LASRC), 5% Na2CO3 SRC (SCASRC), NaCl SRC (SCSRC), CaCl2 SRC (CCSRC), FeCl3 SRC (FCSRC), sodium cholate SRC (SCHSRC), NaOH (pH 10) SRC (SHSRC), Na2CO3 (pH 10) SRC (SCABSRC) and SDS (pH 10) SRC (SDSSRC) values, and a Chopin SRC kit was used to measure the SRC value. SRCs of the oat flours increased when the solvents turned from neutral (water and NaCl) to acidic (5% lactic acid) or alkaline (5% Na2CO3, CaCl2, FeCl3, NaOH and pH 10 Na2CO3), and rose as the metal ion valencies of the metal salts (NaCl, CaCl2 and FeCl3) increased. The β-glucan contents were significantly positively correlated with the SCSRC (0.83**), CCSRC (0.82**), SCHSRC (0.80**) and FCSRC (0.78*). SRC measurements of β-glucan in oat flours revealed that the CCSRC values were related with β-glucan (0.64*) but not related with protein and starch. CaCl2 could therefore potentially be exploited as a reagent for β-glucan assay. PMID:28335393

  5. Green solvents and technologies for oil extraction from oilseeds.

    Science.gov (United States)

    Kumar, S P Jeevan; Prasad, S Rajendra; Banerjee, Rintu; Agarwal, Dinesh K; Kulkarni, Kalyani S; Ramesh, K V

    2017-01-01

    Oilseeds are crucial for the nutritional security of the global population. The conventional technology used for oil extraction from oilseeds is by solvent extraction. In solvent extraction, n-hexane is used as a solvent for its attributes such as simple recovery, non-polar nature, low latent heat of vaporization (330 kJ/kg) and high selectivity to solvents. However, usage of hexane as a solvent has lead to several repercussions such as air pollution, toxicity and harmfulness that prompted to look for alternative options. To circumvent the problem, green solvents could be a promising approach to replace solvent extraction. In this review, green solvents and technology like aqueous assisted enzyme extraction are better solution for oil extraction from oilseeds. Enzyme mediated extraction is eco-friendly, can obtain higher yields, cost-effective and aids in obtaining co-products without any damage. Enzyme technology has great potential for oil extraction in oilseed industry. Similarly, green solvents such as terpenes and ionic liquids have tremendous solvent properties that enable to extract the oil in eco-friendly manner. These green solvents and technologies are considered green owing to the attributes of energy reduction, eco-friendliness, non-toxicity and non-harmfulness. Hence, the review is mainly focussed on the prospects and challenges of green solvents and technology as the best option to replace the conventional methods without compromising the quality of the extracted products.

  6. 27 CFR 21.125 - Rubber hydrocarbon solvent.

    Science.gov (United States)

    2010-04-01

    ... 27 Alcohol, Tobacco Products and Firearms 1 2010-04-01 2010-04-01 false Rubber hydrocarbon solvent. 21.125 Section 21.125 Alcohol, Tobacco Products and Firearms ALCOHOL AND TOBACCO TAX AND TRADE BUREAU....125 Rubber hydrocarbon solvent. (a) Rubber hydrocarbon solvent is a petroleum derivative....

  7. Dynamics of solvent-free grafted nanoparticles

    KAUST Repository

    Chremos, Alexandros

    2012-01-01

    The diffusivity and structural relaxation characteristics of oligomer-grafted nanoparticles have been investigated with simulations of a previously proposed coarse-grained model at atmospheric pressure. Solvent-free, polymer-grafted nanoparticles as well as grafted nanoparticles in a melt were compared to a reference system of bare (ungrafted) particles in a melt. Whereas longer chains lead to a larger hydrodynamic radius and lower relative diffusivity for grafted particles in a melt, bulk solvent-free nanoparticles with longer chains have higher relative diffusivities than their short chain counterparts. Solvent-free nanoparticles with short chains undergo a glass transition as indicated by a vanishing diffusivity, diverging structural relaxation time and the formation of body-centered-cubic-like order. Nanoparticles with longer chains exhibit a more gradual increase in the structural relaxation time with decreasing temperature and concomitantly increasing particle volume fraction. The diffusivity of the long chain nanoparticles exhibits a minimum at an intermediate temperature and volume fraction where the polymer brushes of neighboring particles overlap, but must stretch to fill the interparticle space. © 2012 American Institute of Physics.

  8. Solubility of C60 in solvent mixtures.

    Science.gov (United States)

    Kulkarni, Pradnya P; Jafvert, Chad T

    2008-02-01

    The potential large-scale production of fullerene C60 and its widespread use in consumer products may translate into occupational and public exposure and in long-term environmental exposure. To assess the risk and fate of C60 in the environment, it is important to understand its solvate formation in common industrial solvents as the solvates may affect various properties of C60 including reactivity and toxicity, particularly when solvates occur in C60 clusters. In this study, the solubility measurements in mixed solvent system can provide useful information about solvate formation. The solubility of C60 was measured in pure toluene, tetrahydrofuran, ethanol, and acetonitrile to be 3000, 11, 1.4, and 0.04 mg/L, respectively. Additionally, the solubility of C60 was measured in mixtures of toluene-acetonitrile, toluene-ethanol, toluene-tetrahydrofuran, and acetonitrile-tetrahydrofuran. The solubility data were modeled with some accuracy using Wohl's equation. The estimated crystal energy term for C60 in tetrahydrofuran was different than that in the other solvents, indicating that the C60 solid phase in equilibrium with tetrahydrofuran solution may be a solvated crystal.

  9. Modeling the temperature dependent interfacial tension between organic solvents and water using dissipative particle dynamics.

    Science.gov (United States)

    Mayoral, E; Goicochea, A Gama

    2013-03-07

    The interfacial tension between organic solvents and water at different temperatures is predicted using coarse-grained, mesoscopic Dissipative Particle Dynamics (DPD) simulations. The temperature effect of the DPD repulsive interaction parameters, aij, for the different components is calculated from the dependence of the Flory-Huggins χ parameter on temperature, by means of the solubility parameters. Atomistic simulations were carried out for the calculation of the solubility parameters for different organic compounds at different temperatures in order to estimate χ and then the aij coefficients. We validate this parametrization through the study of the interfacial tension in a mixture of benzene and water, and cyclohexane and water, varying the temperature. The predictions of our simulations are found to be in good agreement with experimental data taken from the literature, and show that the use of the solubility parameter at different temperatures to obtain the repulsive DPD parameters is a good alternative to introduce the effect of temperature in these systems.

  10. Modelling of retention of pesticides in reversed-phase high-performance liquid chromatography: Quantitative structure-retention relationships based on solute quantum-chemical descriptors and experimental (solvatochromic and spin-probe) mobile phase descriptors

    Energy Technology Data Exchange (ETDEWEB)

    D' Archivio, Angelo Antonio [Dipartimento di Chimica, Ingegneria Chimica e Materiali, Universita degli Studi di L' Aquila, Via Vetoio, 67010 Coppito, L' Aquila (Italy)]. E-mail: darchivi@univaq.it; Ruggieri, Fabrizio [Dipartimento di Chimica, Ingegneria Chimica e Materiali, Universita degli Studi di L' Aquila, Via Vetoio, 67010 Coppito, L' Aquila (Italy); Mazzeo, Pietro [Dipartimento di Chimica, Ingegneria Chimica e Materiali, Universita degli Studi di L' Aquila, Via Vetoio, 67010 Coppito, L' Aquila (Italy); Tettamanti, Enzo [Dipartimento di Scienze Biomediche Comparate, Universita di Teramo, P.zzale A. Moro 45, 64100 Teramo (Italy)

    2007-06-19

    A quantitative structure-retention relationship (QSRR) analysis based on multilinear regression (MLR) and artificial neural networks (ANNs) is carried out to model the combined effect of solute structure and eluent composition on the retention behaviour of pesticides in isocratic reversed-phase high-performance liquid chromatography (RP-HPLC). The octanol-water partition coefficient and four quantum chemical descriptors (the total dipole moment, the mean polarizability, the anisotropy of the polarizability and a descriptor of hydrogen-bonding based on the atomic charges on acidic and basic chemical functionalities) are considered as solute descriptors. In order to identify suitable mobile phase descriptors, encoding composition-dependent properties of both methanol- and acetonitrile-containing mobile phases, the Kamlet-Taft solvatochromic parameters (polarity-dipolarity, hydrogen-bond acidity and hydrogen-bond basicity, {pi} {sup *}, {alpha} and {beta}, respectively) and the {sup 14}N hyperfine-splitting constant (a {sub N}) of a spin-probe dissolved in the eluent are examined. A satisfactory description of mobile phase properties influencing the solute retention is provided by a {sub N} and {beta} or alternatively {pi} {sup *} and {beta}. The two seven-parameter models resulting from combination of a {sub N} and {beta}, or {pi} {sup *} and {beta}, with the solute descriptors were tested on a set of 26 pesticides representative of 10 different chemical classes in a wide range of mobile phase composition (30-60% (v/v) water-methanol and 30-70% (v/v) water-acetonitrile). Within the explored experimental range, the acidity of the eluent, as quantified by {alpha}, is almost constant, and this parameter is in fact irrelevant. The results reveal that a {sub N} and {pi} {sup *}, that can be considered as interchangeable mobile phase descriptors, are the most influent variables in the respective models. The predictive ability of the proposed models, as tested on an

  11. An evaluation of the applicability of the EPA Organic Leachate Model to leaching of solvent and non-solvent wastes

    OpenAIRE

    Bosserman, Carolyn Whitney

    1989-01-01

    The author evaluated the applicability of the Environmental Protection Agency's Organic Leachate Model to wastes containing organic solvents and other organic compounds ("non-solvents"), and determined that the model tends to overestimate the leaching of organic solvents and other organic compounds. Furthermore, when evaluated for its ability to predict leaching of organic compounds, the model was found to predict the leaching of organic solvent compounds with some accuracy, with a correlatio...

  12. Measurement of oxygen transfer from air into organic solvents

    DEFF Research Database (Denmark)

    Ramesh, Hemalata; Mayr, Torsten; Hobisch, Mathias

    2016-01-01

    applications). Subsequently, we measured the oxygen transfer rates from air into these organic solvents. Conclusion The measurement of oxygen transfer rates from air into organic solvents using the dynamic method was established using the solvent resistant optical sensor. The feasibility of online oxygen...... biological reactions require the supply of oxygen, most normally from air. However, reliable on-line measurements of oxygen concentration in organic solvents (and hence oxygen transfer rates from air to the solvent) has to date proven impossible due limitations in the current analytical methods. Results...

  13. The Development of a Microscale Continuous Hot Solvent Extractor

    Science.gov (United States)

    Wesolowski, Steve S.; Mulcahy, Thomas; Zafoni, Christina M.; Wesolowski, Wayne E.

    1999-08-01

    The extraction of soluble materials from organic samples plays an important role in many industries. For example, extraction of oils and grease from soil samples using traditional Soxhlet extractors is an essential procedure in waste management laboratories. These extractors use from 25 to 1000 mL of solvent per sample and the waste solvent is typically distilled or simply disposed of upon completion of the extraction. To minimize the waste solvent produced, we have developed a microscale continuous hot solvent extractor that effectively extracts 100-500-mg samples using about 4 mL of solvent.

  14. Imipramine Drug Delivery Via Swbnnts and Dwcnts: NMR and Solvent Effect

    Directory of Open Access Journals (Sweden)

    Azadeh Nazarian

    2015-09-01

    Full Text Available The drug delivery via multi wall nano tube has been studied using ab-initio and QM/MM methods. We have studied the solvent effects on the relative energies and dipole moment values and the structural properties of water, methanol surrounding single-walled and multi walled carbon and boron nitride nanotubes. In this study we investigated the polar solvents effects on MWCNT within the Onsager self - consistent reaction field (SCRF model using a Hartree-Fock method and the temperature effect on the stability of SWCNT in various. Because some of the physicochemical parameters related to structural properties of SWCNT, we used different force fields to determine energy and other types of geometrical parameters, on the particular SWCNT.

  15. Rapid and solvent-saving liquefaction of woody biomass using microwave-ultrasonic assisted technology.

    Science.gov (United States)

    Lu, Zexiang; Wu, Zhengguo; Fan, Liwei; Zhang, Hui; Liao, Yiqiang; Zheng, Deyong; Wang, Siqun

    2016-01-01

    A novel process to rapidly liquefy sawdust using reduced quantities of solvent, was successfully carried out via microwave-ultrasonic assisted technology (MUAT) in a sulphuric acid/polyethylene glycol 400-glycerol catalytic system. The influences of some key parameters on the liquefaction yield were investigated. The results showed that compared with traditional liquefaction, the introduction of MUAT allowed the solvent dosage to be halved and shortened the liquefaction time from 60 to 20 min. The liquefaction yield reached 91% under the optimal conditions. However, the influence on the yield of some parameters such as catalyst concentration, was similar to that of traditional liquefaction, indicating that the application of MUAT possibly only intensified heat and mass transfer rather than altering either the degradation mechanism or pathway. The introduction of MUAT as a process intensification technology has good industrial application potential for woody biomass liquefaction.

  16. Influência da temperatura na solubilidade de beta-caroteno em solventes orgânicos à pressão ambiente Effect of temperature on the solubility of beta-carotene in organic solvents under ambient pressure

    Directory of Open Access Journals (Sweden)

    Marcus Vinícius Três

    2007-12-01

    Full Text Available O presente trabalho reporta dados experimentais de solubilidade em pressão ambiente de beta-caroteno em solventes orgânicos puros (etanol, acetona, acetato de etila e diclorometano e em misturas de tais solventes no intervalo de temperatura de 10 a 60 °C. Para este fim, adotou-se o método gravimétrico para a determinação da solubilidade, utilizando células encamisadas de equilíbrio. Os resultados mostraram que valores mais elevados de solubilidade são obtidos quando foram empregados solventes com parâmetros de solubilidade mais próximos daquele do soluto. Verificou-se que o aumento da temperatura, tanto para solventes puros, como para as misturas de solventes, acarretou num aumento da solubilidade do beta-caroteno para todas as condições experimentais. Observou-se ainda, que nas condições experimentais investigadas, não houve sinergismo significativo para as misturas de solventes quando comparadas aos valores de solubilidade obtidos para os solventes puros. O modelo UNIFAC se mostrou útil na previsão qualitativa dos resultados de solubilidade.This work reports experimental data of the solubility of beta-carotene in pure acetone, ethyl acetate, ethanol and dichloromethane and in mixtures of these organic solvents in the temperature range of 10 to 60 °C under ambient pressure. The gravimetric method was employed to determine the solubility, using glass equilibrium cells. The results showed that the best solvents were those having solubility parameter values close to that of the solute. It was found that raising the temperature caused the solute solubility values for both pure and solvent mixtures to increase under all the experimental conditions. Moreover, no synergetic effects were observed on the solubility of beta-carotene in solvent mixtures compared to pure solvents in the temperature range investigated. The UNIFAC model proved to be useful in predicting the solubility data.

  17. Enthalpy and entropy contributions to the solubility of sulphamethoxypyridazine in solvent mixtures showing two solubility maxima.

    Science.gov (United States)

    Bustamante, P; Escalera, B

    1995-07-01

    The solubility of sulphamethoxypyridazine was measured at several temperatures in mixtures of water:ethanol and ethanol:ethyl acetate. Sulphamethoxypyridazine was chosen as a model drug to compare the solvation effects of proton donor-proton acceptor (water and ethanol) and proton acceptor (ethyl acetate) solvents and mixtures of these solvents because this drug contains functional groups capable of Lewis acid-base interaction. A plot of the mole fraction solubility against the solubility parameter (delta 1 = 30.87 MPa1/2 (20:80 v/v water:ethanol) and another at delta 1 = 20.88 MPa1/2 (30:70 v/v ethanol:ethyl acetate) at all the temperatures under study. The enthalpies and entropies of mixing as well as the enthalpies and entropies of transfer of sulphamethoxypyridazine from ethanol of mixing as well as the enthalpies and entropies of transfer of sulphamethoxypyridazine from ethanol to water:ethanol and ethanol:ethyl acetate mixtures were calculated to compare solvation characteristics of the solvent mixtures toward the drug. As ethanol is added to water, the entropy increases and the structure of the solvent mixture became less ordered, favouring the interaction of the drug with the solvent mixture. On the other hand, in the case of the ethanol:ethyl acetate mixture, solubility is favoured by the more negative enthalpy values. This way, the same result, i.e. a solubility maximum, is obtained by different routes. In the ethanol:water mixtures, the dissolution process if entropy-controlled while enthalpy is the driving force in the case of ethanol:ethyl acetate mixtures. The two solvent systems show enthalpy-entropy compensation. Water deviates from the linear relationship due possibly to its hydrophobic effect.

  18. Kinetics of 12-Hydroxyoctadecanoic Acid SAFiN Crystallization Rationalized Using Hansen Solubility Parameters.

    Science.gov (United States)

    Rogers, Michael A; Marangoni, Alejandro G

    2016-12-06

    Changes in solvent chemistry influenced kinetics of both nucleation and crystallization of 12-hydroxyoctadecenoic, as determined using differential scanning calorimetry and applying a modified Avrami model to the calorimetric data. Altering solvent properties influenced solvent-gelator compatibility, which in turn altered the chemical potential of the system at the onset of crystallization, the kinetics of gelation, and the resulting 12HOA crystal fiber length. The chemical potential at the onset of crystallization was linearly correlated to both the hydrogen-bonding Hansen solubility parameter and the solvent-gelator vectorial distance in Hansen space, Ra. Our work suggests that solvent properties can be modulated to affect the solubility of 12HOA, which in turn influences the kinetics of crystallization and the self-assembly of this organogelator into supramolecular crystalline structures. Therefore, modulation of solvent properties during organogelation can be used to control fiber length and thus engineer the physical properties of the gel.

  19. The structures of CyMe4-BTBP complexes of americium(iii) and europium(iii) in solvents used in solvent extraction, explaining their separation properties.

    Science.gov (United States)

    Ekberg, Christian; Löfström-Engdahl, Elin; Aneheim, Emma; Foreman, Mark R StJ; Geist, Andreas; Lundberg, Daniel; Denecke, Melissa; Persson, Ingmar

    2015-11-14

    Separation of trivalent actinoid (An(iii)) and lanthanoid (Ln(iii)) ions is extremely challenging due to their similar ionic radii and chemical properties. Poly-aromatic nitrogen compounds acting as tetradentate chelating ligands to the metal ions in the extraction, have the ability to sufficiently separate An(iii) from Ln(iii). One of these compounds, 6,6'-bis(5,5,8,8-tetramethyl-5,6,7,8-tetrahydro-benzol[1,2,4]triazin-3-yl)[2,2]bipyridine, CyMe4-BTBP, has proven to be resistant towards acidic environments and strong radiation from radioactive decomposition. EXAFS studies of the dicomplexes of CyMe4-BTBP with americium(iii) and europium(iii) in nitrobenzene, cyclohexanone, 1-hexanol, 1-octanol and malonamide (DMDOHEMA) in 1-octanol have been carried out to get a deeper understanding of the parameters responsible for the separation. The predominating complexes independent of solvent used are [Am(CyMe4-BTBP)2(NO3)](2+) and [Eu(CyMe4-BTBP)2](3+), respectively, which are present as outer-sphere ion-pairs with nitrate ions in the studied solvents with low relative permittivity. The presence of a nitrate ion in the first coordination sphere of the americium(iii) complex compensates the charge density of the complex considerably in comparison when only outer-sphere ion-pairs are formed as for the [Eu(CyMe4-BTBP)2](3+) complex. The stability and solubility of a complex in a solvent with low relative permittivity increase with decreasing charge density. The [Am(CyMe4-BTBP)2(NO3)](2+) complex will therefore be increasingly soluble and stabilized over the [Eu(CyMe4-BTBP)2](3+) complex in solvents with decreasing relative permittivity of the solvent. The separation of americium(iii) from europium(iii) with CyMe4-BTBP as extraction agent will increase with decreasing relative permittivity of the solvent, and thereby also with decreasing solubility of CyMe4-BTBP. The choice of solvent is therefore a balance of a high separation factor and sufficient solubility of the CyMe4-BTBP

  20. Depleting depletion: Polymer swelling in poor solvent mixtures

    Science.gov (United States)

    Mukherji, Debashish; Marques, Carlos; Stuehn, Torsten; Kremer, Kurt

    A polymer collapses in a solvent when the solvent particles dislike monomers more than the repulsion between monomers. This leads to an effective attraction between monomers, also referred to as depletion induced attraction. This attraction is the key factor behind standard polymer collapse in poor solvents. Strikingly, even if a polymer exhibits poor solvent condition in two different solvents, it can also swell in mixtures of these two poor solvents. This collapse-swelling-collapse scenario is displayed by poly(methyl methacrylate) (PMMA) in aqueous alcohol. Using molecular dynamics simulations of a thermodynamically consistent generic model and theoretical arguments, we unveil the microscopic origin of this phenomenon. Our analysis suggests that a subtle interplay of the bulk solution properties and the local depletion forces reduces depletion effects, thus dictating polymer swelling in poor solvent mixtures.

  1. Preparation of Soybean Protein Concentrate with Mixed Solvents of Hexane-Aqueous Alcohol

    Institute of Scientific and Technical Information of China (English)

    ZhangWeinong; LiuDachuan

    2002-01-01

    Preparation of soybean protein concentrate with the mixed solvents of hexane-aqueous alcohol was studied in this paper.The optimum technology parameters were obtained by orthogonal tests.The results of experiments showed that the qualities of the product were good not only on taste of the product were good not only on tasted and color,but also on high solubility-NSI value was 48.80%.

  2. Single Stage Contactor Testing Of The Next Generation Solvent Blend

    Energy Technology Data Exchange (ETDEWEB)

    Herman, D. T.; Peters, T. B.; Duignan, M. R.; Williams, M. R.; Poirier, M. R.; Brass, E. A.; Garrison, A. G.; Ketusky, E. T.

    2014-01-06

    The Modular Caustic Side Solvent Extraction (CSSX) Unit (MCU) facility at the Savannah River Site (SRS) is actively pursuing the transition from the current BOBCalixC6 based solvent to the Next Generation Solvent (NGS)-MCU solvent to increase the cesium decontamination factor. To support this integration of NGS into the MCU facility the Savannah River National Laboratory (SRNL) performed testing of a blend of the NGS (MaxCalix based solvent) with the current solvent (BOBCalixC6 based solvent) for the removal of cesium (Cs) from the liquid salt waste stream. This testing utilized a blend of BOBCalixC6 based solvent and the NGS with the new extractant, MaxCalix, as well as a new suppressor, tris(3,7dimethyloctyl) guanidine. Single stage tests were conducted using the full size V-05 and V-10 liquid-to-liquid centrifugal contactors installed at SRNL. These tests were designed to determine the mass transfer and hydraulic characteristics with the NGS solvent blended with the projected heel of the BOBCalixC6 based solvent that will exist in MCU at time of transition. The test program evaluated the amount of organic carryover and the droplet size of the organic carryover phases using several analytical methods. The results indicate that hydraulically, the NGS solvent performed hydraulically similar to the current solvent which was expected. For the organic carryover 93% of the solvent is predicted to be recovered from the stripping operation and 96% from the extraction operation. As for the mass transfer, the NGS solvent significantly improved the cesium DF by at least an order of magnitude when extrapolating the One-stage results to actual Seven-stage extraction operation with a stage efficiency of 95%.

  3. Next Generation Solvent Development for Caustic-Side Solvent Extraction of Cesium

    Energy Technology Data Exchange (ETDEWEB)

    Moyer, Bruce A. [Oak Ridge National Laboratory (ORNL), Oak Ridge, TN (United States); Birdwell, Joseph F. [Oak Ridge National Laboratory (ORNL), Oak Ridge, TN (United States); Bonnesen, Peter V. [Oak Ridge National Laboratory (ORNL), Oak Ridge, TN (United States); Bruffey, Stephanie [Oak Ridge National Laboratory (ORNL), Oak Ridge, TN (United States)

    2014-03-01

    This report summarizes the FY 2010 and 2011 accomplishments at Oak Ridge National Laboratory (ORNL) in developing the Next Generation Caustic-Side Solvent Extraction (NG-CSSX) process, referred to commonly as the Next Generation Solvent (NGS), under funding from the U.S. Department of Energy, Office of Environmental Management (DOE-EM), Office of Technology Innovation and Development. The primary product of this effort is a process solvent and preliminary flowsheet capable of meeting a target decontamination factor (DF) of 40,000 for worst-case Savannah River Site (SRS) waste with a concentration factor of 15 or higher in the 18-stage equipment configuration of the SRS Modular Caustic-Side Solvent Extraction Unit (MCU). In addition, the NG-CSSX process may be readily adapted for use in the SRS Salt Waste Processing Facility (SWPF) or in supplemental tank-waste treatment at Hanford upon appropriate solvent or flowsheet modifications. Efforts in FY 2010 focused on developing a solvent composition and process flowsheet for MCU implementation. In FY 2011 accomplishments at ORNL involved a wide array of chemical-development activities and testing up through single-stage hydraulic and mass-transfer tests in 5-cm centrifugal contactors. Under subcontract from ORNL, Argonne National Laboratory (ANL) designed a preliminary flowsheet using ORNL cesium distribution data, and Tennessee Technological University confirmed a chemical model for cesium distribution ratios (DCs) as a function of feed composition. Inter laboratory efforts were coordinated with complementary engineering tests carried out (and reported separately) by personnel at Savannah River National Laboratory (SRNL) and Savannah River Remediation (SRR) with helpful advice by Parsons Engineering and General Atomics on aspects of possible SWPF implementation.

  4. Next Generation Solvent (NGS): Development for Caustic-Side Solvent Extraction of Cesium

    Energy Technology Data Exchange (ETDEWEB)

    Moyer, Bruce A. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Birdwell, Jr, Joseph F. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Bonnesen, Peter V. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Bruffey, Stephanie H. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Delmau, Laetitia Helene [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Duncan, Nathan C. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Ensor, Dale [Tennessee Technological Univ., Cookeville, TN (United States); Hill, Talon G. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Lee, Denise L. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Rajbanshi, Arbin [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Roach, Benjamin D. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Szczygiel, Patricia L. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Sloop, Jr., Frederick V. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Stoner, Erica L. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Williams, Neil J. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

    2014-03-01

    This report summarizes the FY 2010 and 2011 accomplishments at Oak Ridge National Laboratory (ORNL) in developing the Next Generation Caustic-Side Solvent Extraction (NG-CSSX) process, referred to commonly as the Next Generation Solvent (NGS), under funding from the U.S. Department of Energy, Office of Environmental Management (DOE-EM), Office of Technology Innovation and Development. The primary product of this effort is a process solvent and preliminary flowsheet capable of meeting a target decontamination factor (DF) of 40,000 for worst-case Savannah River Site (SRS) waste with a concentration factor of 15 or higher in the 18-stage equipment configuration of the SRS Modular Caustic-Side Solvent Extraction Unit (MCU). In addition, the NG-CSSX process may be readily adapted for use in the SRS Salt Waste Processing Facility (SWPF) or in supplemental tank-waste treatment at Hanford upon appropriate solvent or flowsheet modifications. Efforts in FY 2010 focused on developing a solvent composition and process flowsheet for MCU implementation. In FY 2011 accomplishments at ORNL involved a wide array of chemical-development activities and testing up through single-stage hydraulic and mass-transfer tests in 5-cm centrifugal contactors. Under subcontract from ORNL, Argonne National Laboratory (ANL) designed a preliminary flowsheet using ORNL cesium distribution data, and Tennessee Technological University confirmed a chemical model for cesium distribution ratios (DCs) as a function of feed composition. Interlaboratory efforts were coordinated with complementary engineering tests carried out (and reported separately) by personnel at Savannah River National Laboratory (SRNL) and Savannah River Remediation (SRR) with helpful advice by Parsons Engineering and General Atomics on aspects of possible SWPF implementation.

  5. Block copolymer alignment by shear induced during solvent vapor annealing with a crosslinked elastomer capping layer

    Science.gov (United States)

    Vogt, Bryan

    2014-03-01

    The long range alignment of block copolymers (BCPs) is generally accomplished through application of a gradient shear force or by topographical or chemical cues patterned into the substrate. These techniques require lithographic patterning, specialty substrates or custom built equipment to achieve the alignment, which limits the broad academic application of aligned BCPs. One technique to improve the large range ordering of BCPs is solvent vapor annealing (SVA), which exposes the BCP film to a controlled atmosphere of solvent vapor to swell the BCP and provide significant enhancements in the chain mobility. Here, we discuss a minor modification of the SVA process; a thin piece of crosslinked poly(dimethyl siloxane) (PDMS) is placed on top of the BCP film before SVA. Exposure to organic solvent vapors causes the PDMS to swell, while the solvent also plasticizes the BCP film. Removal of the solvent induces a shear to the BCP film as the PDMS shrinks back to its initial dimensions. The shape of the PDMS cap determines the anisotropy in the stress applied on deswelling that aligns and orients the BCP domains. Polystyrene-block-polyisoprene-block-polystyrene (SIS) is utilized as a model system to illustrate how the processing parameters impact the orientation as determined by both grazing incidence small angle x-ray scattering (GISAXS) and atomic force microscopy (AFM). Quantification of the alignment by Herman's orientational parameter (S) illustrates high degree of alignment (S =0.95) is possible through appropriate selection of processing conditions. This SVA-based alignment method provides a relatively simple method to orient BCP films within general SVA processing protocols.

  6. Compound forming extractants, solvating solvents and inert solvents IUPAC chemical data series

    CERN Document Server

    Marcus, Y; Kertes, A S

    2013-01-01

    Equilibrium Constants of Liquid-Liquid Distribution Reactions, Part III: Compound Forming Extractants, Solvating Solvents, and Inert Solvents focuses on the compilation of equilibrium constants of various compounds, such as acids, ions, salts, and aqueous solutions. The manuscript presents tables that show the distribution reactions of carboxylic and sulfonic acid extractants and their dimerization and other reactions in the organic phase and extraction reactions of metal ions from aqueous solutions. The book also states that the inorganic anions in these solutions are irrelevant, since they d

  7. Steam and solvent injection as an advanced recovering method for heavy oil reservoirs; Injecao de vapor e solvente como um metodo de recuperacao avancada em reservatorios de oleo pesado

    Energy Technology Data Exchange (ETDEWEB)

    Galvao, Edney Rafael V.P.; Rodrigues, Marcos Allyson F.; Barbosa, Janaina Medeiros D.; Barillas, Jennys Lourdes M.; Dutra Junior, Tarcilio V.; Mata, Wilson da [Universidade Federal do Rio Grande do Norte (UFRN), Natal, RN (Brazil)

    2008-07-01

    Currently a resource more and more used by the petroleum industry to increase the efficiency of steam flood mechanism is the addition of solvents. The process can be understood as a combination of a thermal method (steam injection) with a miscible method (solvent injection), promoting, thus, the reduction of interfacial tensions and oil viscosity. The mobility of the displaced fluid is then improved, resulting in an increase of oil recovery. To better understand this improved oil recovery method, a numerical study of the process was driven contemplating the effects of some operational parameters (distance between wells, injection fluids rate, kind of solvent and injected solvent volume) on the accumulated production of oil and recovery factor. Semisynthetic models were used in this study but reservoir data can be extrapolated for practical applications situations on Potiguar Basin. Simulations were performed in STARS (CMG, 2007.11). It was found that injected solvent volumes increased oil recovery and oil rates. Further the majority of the injected solvent was produced and can be recycled. (author)

  8. Extended solvent-contact model for protein solvation: test cases for dipeptides.

    Science.gov (United States)

    Choi, Hwanho; Kang, Hongsuk; Park, Hwangseo

    2013-05-01

    Solvation effects are critically important in the structural stabilization and functional optimization of proteins. Here, we propose a new solvation free energy function for proteins, and test its applicability in predicting the solvation free energies of dipeptides. The present solvation model involves the improvement of the previous solvent-contact model assuming that the molecular solvation free energy could be given by the sum over the individual atomic contributions. In addition to the existing solvent-contact term, the modified solvation free energy function includes the self-solvation term that reflects the effects of intramolecular interactions in the solute molecule on solute-solvent interactions. Four kinds of atomic parameters should be determined in this solvation model: atomic fragmental volume, maximum atomic occupancy, atomic solvation, and atomic self-solvation parameters. All of these parameters for 16 atom types are optimized with a standard genetic algorithm in such a way to minimize the difference between the solvation free energies of dipeptides obtained from high-level quantum chemical calculations and those predicted by the solvation free energy function. The solvation free energies of dipeptides estimated from the new solvation model are in good agreement with the quantum chemical results. Therefore, the optimized solvation free energy function is expected to be useful for examining the structural and energetic features of proteins in aqueous solution.

  9. Computational prediction of octanol-water partition coefficient based on the extended solvent-contact model.

    Science.gov (United States)

    Kim, Taeho; Park, Hwangseo

    2015-07-01

    The logarithm of 1-octanol/water partition coefficient (LogP) is one of the most important molecular design parameters in drug discovery. Assuming that LogP can be calculated from the difference between the solvation free energy of a molecule in water and that in 1-octanol, we propose a method for predicting the molecular LogP values based on the extended solvent-contact model. To obtain the molecular solvation free energy data for the two solvents, a proper potential energy function was defined for each solvent with respect to atomic distributions and three kinds of atomic parameters. Total 205 atomic parameters were optimized with the standard genetic algorithm using the training set consisting of 139 organic molecules with varying shapes and functional groups. The LogP values estimated with the two optimized solvation free energy functions compared reasonably well with the experimental results with the associated squared correlation coefficient and root mean square error of 0.824 and 0.697, respectively. Besides the prediction accuracy, the present method has the merit in practical applications because molecular LogP values can be computed straightforwardly from the simple potential energy functions without the need to calculate various molecular descriptors. The methods for enhancing the accuracy of the present prediction model are also discussed.

  10. Scenarios Evaluation Tool for Chlorinated Solvent MNA

    Energy Technology Data Exchange (ETDEWEB)

    Vangelas, Karen; Michael J. Truex; Charles J. Newell; Brian Looney

    2007-02-28

    Over the past three decades, much progress has been made in the remediation of chlorinated solvents from the subsurface. Yet these pervasive contaminants continue to present a significant challenge to the U.S. Department of Energy (DOE), other federal agencies, and other public and private organizations. The physical and chemical properties of chlorinated solvents make it difficult to rapidly reach the low concentrations typically set as regulatory limits. These technical challenges often result in high costs and long remediation time frames. In 2003, the DOE through the Office of Environmental Management funded a science-based technical project that uses the U.S. Environmental Protection Agency's technical protocol (EPA, 1998) and directives (EPA, 1999) on Monitored Natural Attenuation (MNA) as the foundation on which to introduce supporting concepts and new scientific developments that will support remediation of chlorinated solvents based on natural attenuation processes. This project supports the direction in which many site owners want to move to complete the remediation of their site(s), that being to complete the active treatment portion of the remedial effort and transition into MNA. The overarching objective of the effort was to examine environmental remedies that are based on natural processes--remedies such as Monitored Natural Attenuation (MNA) or Enhanced Attenuation (EA). The research program did identify several specific opportunities for advances based on: (1) mass balance as the central framework for attenuation based remedies, (2) scientific advancements and achievements during the past ten years, (3) regulatory and policy development and real-world experience using MNA, and (4) exploration of various ideas for integrating attenuation remedies into a systematic set of ''combined remedies'' for contaminated sites. These opportunities are summarized herein and are addressed in more detail in referenced project documents and

  11. Alternative Bio-Based Solvents for Extraction of Fat and Oils: Solubility Prediction, Global Yield, Extraction Kinetics, Chemical Composition and Cost of Manufacturing

    Directory of Open Access Journals (Sweden)

    Anne-Gaëlle Sicaire

    2015-04-01

    Full Text Available The present study was designed to evaluate the performance of alternative bio-based solvents, more especially 2-methyltetrahydrofuran, obtained from crop’s byproducts for the substitution of petroleum solvents such as hexane in the extraction of fat and oils for food (edible oil and non-food (bio fuel applications. First a solvent selection as well as an evaluation of the performance was made with Hansen Solubility Parameters and the COnductor-like Screening MOdel for Realistic Solvation (COSMO-RS simulations. Experiments were performed on rapeseed oil extraction at laboratory and pilot plant scale for the determination of lipid yields, extraction kinetics, diffusion modeling, and complete lipid composition in term of fatty acids and micronutrients (sterols, tocopherols and tocotrienols. Finally, economic and energetic evaluations of the process were conducted to estimate the cost of manufacturing using 2-methyltetrahydrofuran (MeTHF as alternative solvent compared to hexane as petroleum solvent.

  12. Alternative bio-based solvents for extraction of fat and oils: solubility prediction, global yield, extraction kinetics, chemical composition and cost of manufacturing.

    Science.gov (United States)

    Sicaire, Anne-Gaëlle; Vian, Maryline; Fine, Frédéric; Joffre, Florent; Carré, Patrick; Tostain, Sylvain; Chemat, Farid

    2015-04-15

    The present study was designed to evaluate the performance of alternative bio-based solvents, more especially 2-methyltetrahydrofuran, obtained from crop's byproducts for the substitution of petroleum solvents such as hexane in the extraction of fat and oils for food (edible oil) and non-food (bio fuel) applications. First a solvent selection as well as an evaluation of the performance was made with Hansen Solubility Parameters and the COnductor-like Screening MOdel for Realistic Solvation (COSMO-RS) simulations. Experiments were performed on rapeseed oil extraction at laboratory and pilot plant scale for the determination of lipid yields, extraction kinetics, diffusion modeling, and complete lipid composition in term of fatty acids and micronutrients (sterols, tocopherols and tocotrienols). Finally, economic and energetic evaluations of the process were conducted to estimate the cost of manufacturing using 2-methyltetrahydrofuran (MeTHF) as alternative solvent compared to hexane as petroleum solvent.

  13. Sharp Interface Tracking in Rotating Microflows of Solvent Extraction

    Energy Technology Data Exchange (ETDEWEB)

    Glimm, James [Stony Brook Univ., NY (United States); Almeida, Valmor de [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Jiao, Xiangmin [Stony Brook Univ., NY (United States); Sims, Brett [City Univ. (CUNY), NY (United States). Borough of Manhattan Community College; Li, Xaiolin [Stony Brook Univ., NY (United States)

    2013-01-08

    The objective of this project is to develop a specialized sharp interface tracking simulation capability for predicting interaction of micron-sized drops and bubbles in rotating flows relevant to optimized design of contactor devices used in solvent extraction processes of spent nuclear fuel reprocessing. The primary outcomes of this project include the capability to resolve drops and bubbles micro-hydrodynamics in solvent extraction contactors, determining from first principles continuum fluid mechanics how micro-drops and bubbles interact with each other and the surrounding shearing fluid for realistic flows. In the near term, this effort will play a central role in providing parameters and insight into the flow dynamics of models that average over coarser scales, say at the millimeter unit length. In the longer term, it will prove to be the platform to conduct full-device, detailed simulations as parallel computing power reaches the exaflop level. The team will develop an accurate simulation tool for flows containing interacting droplets and bubbles with sharp interfaces under conditions that mimic those found in realistic contactor operations. The main objective is to create an off-line simulation capability to model drop and bubble interactions in a domain representative of the averaged length scale. The technical approach is to combine robust interface tracking software, subgrid modeling, validation quality experiments, powerful computational hardware, and a team with simulation modeling, physical modeling and technology integration experience. Simulations will then fully resolve the microflow of drops and bubbles at the microsecond time scale. This approach is computationally intensive but very accurate in treating important coupled physical phenomena in the vicinity of interfaces. The method makes it possible to resolve spatial scales smaller than the typical distance between bubbles and to model some non-equilibrium thermodynamic features such as finite

  14. Mixed solvent system for treating acidic gas

    Energy Technology Data Exchange (ETDEWEB)

    Capobianco, P.J.; Butwell, K.F.; Kossakowski, E.J.

    1987-11-10

    This invention discloses mixtures of alkyl dialcohol amines and mono alkyl ethers of polyethylene glycols which are useful in removing acidic gases from gaseous mixtures. The solvent mixtures contain between 1.5 N and 5.0 N methyl diethanolamine (MDEA), 10 to 40 percent water and the balance is methoxytriglycol (MTG). The overall heat of reaction of the solution is typically less than 500 BTU/lb CO/sub 2/, and remains as a single liquid phase during normal gas scrubber operating conditions.

  15. Cleaning with solvents methods and machinery

    CERN Document Server

    Durkee, John

    2014-01-01

    High-precision cleaning is required across many sectors, including aerospace, defense, medical device manufacturing, pharmaceutical processing, semiconductor/electronics, and more. In this comprehensive reference work, solvent cleaning equipment is thoroughly covered with a focus on the engineering details of its operation and selection. Key data is provided alongside practical guidance, giving scientists and engineers in multiple sectors the information they need not only to choose the correct machine in the first place, but also how to operate it effectively and efficiently. Low emission

  16. PULSED MIXER-SETTLER SOLVENT EXTRACTION CONTACTORS

    Science.gov (United States)

    Figg, W.S.

    1958-08-12

    A mixer-settler extractor is described for contacting immiscible liquids having different specific gravities in order to withdraw one or more components from one liquid with the aid of the other liquid. The extractor consists of a hollow column, a rotary drive shafi extending : through the column with a number of impellers spaced thereon, an equal nunnber of separator plate sets each consisting of one fluorothene and one stainless steel plate with peripheral recesses and flow slots mounted on the column, and a pulse generator. This apparatus is particularly useful in solvent extraction processes for recovering plutonium from aqueous acidic solutions of irradiated uranium.

  17. Solvent extraction of metals with hydroxamic acids.

    Science.gov (United States)

    Vernon, F; Khorassani, J H

    1978-07-01

    Solvent extraction with hydroxamic acids has been investigated. with comparison of aliphatic and aromatic reagents for the extraction of iron, copper, cobalt and nickel. Caprylohydroxamic acid has been evaluated for use in extraction systems for titanium, vanadium, chromium, molybdenum and uranium, both in terms of acidity of aqueous phase and oxidation state of the metal. It has been established that caprylohydroxamic acid in 1-hexanol is a suitable extractant for the removal of titanium(IV), vanadium(V), chromium(VI), molybdenum(VI) and uranium(VI) from 6M hydrochloric acid.

  18. Estimation of the nucleation kinetics for the anti-solvent crystallisation of paracetamol in methanol/water solutions

    Science.gov (United States)

    Ó'Ciardhá, Clifford T.; Frawley, Patrick J.; Mitchell, Niall A.

    2011-08-01

    In this work the primary nucleation kinetics have been estimated for the anti-solvent crystallisation of paracetamol in methanol-water solutions from metastable zone widths (MSZW) and induction times at 25 °C. Laser back-scattering via a focused beam reflectance Measurement (FBRM ®) is utilised to detect the onset of nucleation. The theoretical approach of Kubota was employed to estimate the nucleation kinetics, which accounts for the sensitivity of the nucleation detection technique. This approach is expanded in this work to analyse the induction time for an anti-solvent crystallisation process. Solvent composition is known to have a significant impact on the measured induction times and MSZW. The induction time in this paper was measured from 40% to 70% mass water and the MSZW is measured from 40% to 60% mass water. The primary focus of the paper was to gauge the extent of how solvent composition affects nucleation kinetics so that this effect may be incorporated into a population balance model. Furthermore, the effects of solvent composition on the estimated nucleation rates are investigated. The primary nucleation rates were found to decrease with dynamic solvent composition, with the extent of their reduction linked to the gradient of the solubility curve. Finally, both MSZW and induction time methods have been found to produce similar estimates for the nucleation parameters.

  19. A mixed-solvent strategy for facile and green preparation of graphene by liquid-phase exfoliation of graphite

    Science.gov (United States)

    Yi, Min; Shen, Zhigang; Ma, Shulin; Zhang, Xiaojing

    2012-08-01

    A versatile and scalable mixed-solvent strategy, by which two mediocre solvents could be combined into good solvents for exfoliating graphite, is demonstrated for facile and green preparation of graphene by liquid-phase exfoliation of graphite. Mild sonication of crystal graphite powder in a mixture of water and alcohol could yield graphene nanosheets, which formed a highly stable suspension in the mixed solvents. The graphene yield was estimated as 10 wt%. The optimum mass fraction of ethanol in water-ethanol mixtures and isopropanol in water-isopropanol mixtures was experimentally determined as 40 and 55 % respectively, which could be roughly predicted by the theory of Hansen solubility parameters. Statistics based on atomic force microscopic analysis show that up to 86 % of the prepared nanosheets were less than 10-layer thick with a monolayer fraction of 8 %. High resolution transmission electron microscopy, infrared spectroscopy, X-ray diffraction, and Raman spectrum analysis of the vacuum-filtered films suggest the graphene sheets to be largely free of defects and oxides. The proposed mixed-solvent strategy here extends the scope for liquid-phase processing graphene and gives researchers great freedom in designing ideal solvent systems for specific applications.

  20. Solvent exchange using hollow fiber prior to separation and determination of some antioxidants by high performance liquid chromatography.

    Science.gov (United States)

    Farajzadeh, Mir Ali; Jönsson, Jan Ake

    2007-06-26

    This study presents a simple and rapid solvent exchange procedure using a hollow fiber. Antioxidants (Irganox 1010, Irganox 1076 and Irgafos 168) and solvents such as tetrahydrofuran (THF), carbon tetrachloride and toluene were selected as model compounds and sample solvents, respectively. After injection of the sample solution into the hollow fiber and solvent evaporation, the precipitated analytes in lumen and pores of the fiber were washed with methanol (the mobile phase for separation and determination by HPLC-diode array detection) and good chromatographic peaks were obtained. The effect of different parameters such as fiber length, volumes of sample and washing solvents were investigated and the optimum conditions were selected. The repeatability of the method was tested and it was found that the relative standard deviation (R.S.D.) was less than 10% for all analytes. Also enrichment factors of 3.03, 2.21 and 1.19 times were obtained for Irganox 1010, Irganox 1076 and Irgafos 168, respectively, when 200 microL sample and 50 microL methanol (washing solvent) were used.

  1. European solvent industry group generic exposure scenario risk and exposure tool.

    Science.gov (United States)

    Zaleski, Rosemary T; Qian, Hua; Zelenka, Michael P; George-Ares, Anita; Money, Chris

    2014-01-01

    The European Solvents Industry Group (ESIG) Generic Exposure Scenario (GES) Risk and Exposure Tool (EGRET) was developed to facilitate the safety evaluation of consumer uses of solvents, as required by the European Union Registration, Evaluation and Authorization of Chemicals (REACH) Regulation. This exposure-based risk assessment tool provides estimates of both exposure and risk characterization ratios for consumer uses. It builds upon the consumer portion of the European Center for Ecotoxicology and Toxicology of Chemicals (ECETOC) Targeted Risk Assessment (TRA) tool by implementing refinements described in ECETOC TR107. Technical enhancements included the use of additional data to refine scenario defaults and the ability to include additional parameters in exposure calculations. Scenarios were also added to cover all frequently encountered consumer uses of solvents. The TRA tool structure was modified to automatically determine conditions necessary for safe use. EGRET reports results using specific standard phrases in a format consistent with REACH exposure scenario guidance, in order that the outputs can be readily assimilated within safety data sheets and similar information technology systems. Evaluation of tool predictions for a range of commonly encountered consumer uses of solvents found it provides reasonable yet still conservative exposure estimates.

  2. Ultra-high performance size-exclusion chromatography in polar solvents.

    Science.gov (United States)

    Vancoillie, Gertjan; Vergaelen, Maarten; Hoogenboom, Richard

    2016-12-23

    Size-exclusion chromatography (SEC) is amongst the most widely used polymer characterization methods in both academic and industrial polymer research allowing the determination of molecular weight and distribution parameters, i.e. the dispersity (Ɖ), of unknown polymers. The many advantages, including accuracy, reproducibility and low sample consumption, have contributed to the worldwide success of this analytical technique. The current generation of SEC systems have a stationary phase mostly containing highly porous, styrene-divinylbenzene particles allowing for a size-based separation of various polymers in solution but limiting the flow rate and solvent compatibility. Recently, sub-2μm ethylene-bridged hybrid (BEH) packing materials have become available for SEC analysis. These packing materials can not only withstand much higher pressures up to 15000psi but also show high spatial stability towards different solvents. Combining these BEH columns with the ultra-high performance LC (UHPLC) technology opens up UHP-SEC analysis, showing strongly reduced runtimes and unprecedented solvent compatibility. In this work, this novel characterization technique was compared to conventional SEC using both highly viscous and highly polar solvents as eluent, namely N,N-dimethylacetamide (DMAc), N,N-dimethylformamide (DMF) and methanol, focusing on the suitability of the BEH-columns for analysis of highly functional polymers. The results show a high functional group compatibility comparable with conventional SEC with remarkably short runtimes and enhanced resolution in methanol.

  3. Solvent effects on the structure-property relationship of anticonvulsant hydantoin derivatives: A solvatochromic analysis

    Directory of Open Access Journals (Sweden)

    Trišović Nemanja

    2011-10-01

    Full Text Available Abstract Considering the pharmaceutical importance of hydantoins, a set of 25 derivatives of phenytoin, nirvanol and 5-methyl-5-phenylhydantoin, the lipophilicities of which were gradually increased by the introduction of different alkyl, cycloalkyl and alkenyl groups in position N3, was synthesized. Their properties under consideration were either estimated empirically, by UV/Vis spectroscopy, or calculated using established medicinal chemistry software. The UV absorption spectra of the investigated compounds were recorded in the region from 200 to 400 nm, in selected solvents of different polarities. The effects of solvent dipolarity/polarizability and solvent-solute hydrogen bonding interactions were analyzed by means of the linear solvation energy relationship (LSER concept proposed by Kamlet and Taft. Furthermore, the relationships between solvent-solute interactions and selected structural features of the solutes, which are believed to markedly affect the processes of absorption, distribution, metabolism, excretion and toxicity (ADMETox, were discussed. Satisfactory correlations were found between hydrogen bonding properties and solute size and the in silico calculated bioactivity descriptors, in particular %Abs. (human intestinal absorption, log BB (blood-brain barrier permeation and log kA (protein binding affinities parameters. In view of the results of this study, the investigated hydantoin derivatives met the pharmacokinetic criteria for pre-selection as drug candidates and qualified them for the pharmacodynamic phase of antiepileptic drug development.

  4. Determination of physical properties for the mixtures of [BMIM]Cl with different organic solvents

    Institute of Scientific and Technical Information of China (English)

    Hina Saba; Xinjun Zhu; Ye Chen; Yumei Zhang

    2015-01-01

    Physical properties including refractive index, density, viscosity and conductivity for binary mixtures of 1-butyl-3-methyl imidazolium chloride ([BMIM]Cl) and different organic solvents at 298.15 K have been investigated. Ex-cess molar volumes have been calculated and obtained data has been fitted by the Redlich–Kister equation. The density and refractive index were found to increase with increasing concentration of [BMIM]Cl, however, excep-tions do exist as in the case of dimethyl sulfoxide (DMSO)/[BMIM]Cl. For DMSO/[BMIM]Cl, the density decreases with increasing concentration. The addition of different organic solvents was able to disrupt the interactions within mixtures, leading to free mobility of ions. The free mobility of ions has been found to enhance conductivity and decrease viscosity to varying extents in al mixtures studied. It has been observed that solubility parameters, dielectric constants and composition of the solvents used play a vital role in determining the resultant properties. The data obtained wil play an important role in understanding the effect of the addition of organic solvents in ILs to enhance their applicability.

  5. Extraction of coal with solvents in liquid and supercritical state under nonhydrogenating and hydrogenating conditions

    Science.gov (United States)

    Wilhelm, A.; Hedden, K.

    1982-10-01

    The basic steps of coal extraction to determine the optimum conditions for obtaining a higher coal conversion yield in a technical process of supercritical coal extraction were examined. A fixed bed of coal was slowly heated up in a current of pressurized solvent by a nonisothermal technique. The solvent changes its physical state during extraction from a liquid to a supercritical fluid. The formation rates of extract and gaseous products and their integral yields were measured under different extraction conditions. Various coals and lignites as well as different solvents including H-donor solvents and the effect of the addition of molecular hydrogen to the supercritical phase with and without catalyst were studied. Results are interpreted with an extraction scheme, comprising chemical reactions, phase equilibria and transport processes as single steps of the complex extraction procedure. Using a simplified mathematical model, the formation rates of extract as a function of temperature were quantitatively described with effective kinetic parameters. New process for the hydrogenating supercritical extraction of coal, which produces high coal conversion yields is proposed.

  6. Towards a generalized iso-density continuum model for molecular solvents in plane-wave DFT

    Science.gov (United States)

    Gunceler, Deniz; Arias, T. A.

    2017-01-01

    Implicit electron-density solvation models offer a computationally efficient solution to the problem of calculating thermodynamic quantities of solvated systems from first-principles quantum mechanics. However, despite much recent interest in such models, to date the applicability of such models in the plane-wave context to non-aqueous solvents has been limited because the determination of the model parameters requires fitting to a large database of experimental solvation energies for each new solvent considered. This work presents a simple approach to quickly find approximations to the non-electrostatic contributions to the solvation energy, allowing for development of new iso-density models for a large class of protic and aprotic solvents from only simple, single-molecule ab initio calculations and readily available bulk thermodynamic data. Finally, to illustrate the capabilities of the resulting theory, we also calculate the surface solvation energies of crystalline LiF in various different non-aqueous solvents, and discuss the observed trends and their relevance to lithium battery technology.

  7. FT-IR spectroscopy combined with DFT calculation to explore solvent effects of vinyl acetate.

    Science.gov (United States)

    Chen, Yi; Zhang, Hui; Liu, Qing

    2014-05-21

    The infrared vibration frequencies of vinyl acetate (VAc) in 18 different solvents were theoretically computed at Density Function Theory (DFT) B3LYP/6-311G(*) level based on Polarizable Continuum Model (PCM) and experimentally recorded by FT-IR spectroscopy. The solvent-induced long-range bulk electrostatic solvation free energies of VAc (ΔGelec) were calculated by the SMD model. The C=O stretching vibration frequencies of VAc were utilized as a measure of the chemical reactivities of the CC group in VAc. The calculated and experimental C=O stretching vibration frequencies of VAc (νcal(C=O) and νexp(C=O)) were correlated with empirical solvent parameters including the KBM equation, the Swain equation and the linear solvation energy relationships (LSER). Through ab initio calculation, assignments of the two C=O absorption bands of VAc in alcohol solvents were achieved. The PCM, SMD and ab initio calculation offered supporting evidence to explain the FT-IR experimental observations from differing aspects.

  8. Essential roles of protein-solvent many-body correlation in solvent-entropy effect on protein folding and denaturation: comparison between hard-sphere solvent and water.

    Science.gov (United States)

    Oshima, Hiraku; Kinoshita, Masahiro

    2015-04-14

    In earlier works, we showed that the entropic effect originating from the translational displacement of water molecules plays the pivotal role in protein folding and denaturation. The two different solvent models, hard-sphere solvent and model water, were employed in theoretical methods wherein the entropic effect was treated as an essential factor. However, there were similarities and differences in the results obtained from the two solvent models. In the present work, to unveil the physical origins of the similarities and differences, we simultaneously consider structural transition, cold denaturation, and pressure denaturation for the same protein by employing the two solvent models and considering three different thermodynamic states for each solvent model. The solvent-entropy change upon protein folding/unfolding is decomposed into the protein-solvent pair (PA) and many-body (MB) correlation components using the integral equation theories. Each component is further decomposed into the excluded-volume (EV) and solvent-accessible surface (SAS) terms by applying the morphometric approach. The four physically insightful constituents, (PA, EV), (PA, SAS), (MB, EV), and (MB, SAS), are thus obtained. Moreover, (MB, SAS) is discussed by dividing it into two factors. This all-inclusive investigation leads to the following results: (1) the protein-water many-body correlation always plays critical roles in a variety of folding/unfolding processes; (2) the hard-sphere solvent model fails when it does not correctly reproduce the protein-water many-body correlation; (3) the hard-sphere solvent model becomes problematic when the dependence of the many-body correlation on the solvent number density and temperature is essential: it is not quite suited to studies on cold and pressure denaturating of a protein; (4) when the temperature and solvent number density are limited to the ambient values, the hard-sphere solvent model is usually successful; and (5) even at the ambient

  9. Solvent viscosity dependence for enzymatic reactions

    CERN Document Server

    Sitnitsky, A E

    2008-01-01

    A mechanism for relationship of solvent viscosity with reaction rate constant at enzyme action is suggested. It is based on fluctuations of electric field in enzyme active site produced by thermally equilibrium rocking (cranckshaft motion) of the rigid plane (in which the dipole moment $\\approx 3.6 D$ lies) of a favourably located and oriented peptide group (or may be a few of them). Thus the rocking of the plane leads to fluctuations of the electric field of the dipole moment. These fluctuations can interact with the reaction coordinate because the latter in its turn has transition dipole moment due to separation of charges at movement of the reacting system along it. The rocking of the plane of the peptide group is sensitive to the microviscosity of its environment in protein interior and the latter is a function of the solvent viscosity. Thus we obtain an additional factor of interrelationship for these characteristics with the reaction rate constant. We argue that due to the properties of the cranckshaft ...

  10. Non-Ideal Behavior in Solvent Extraction

    Energy Technology Data Exchange (ETDEWEB)

    Peter Zalupski

    2011-09-01

    This report presents a summary of the work performed to meet FCR&D level 3 milestone M31SW050801, 'Complete the year-end report summarizing FY11 experimental and modeling activities.' This work was carried out under the auspices of the Non-Ideality in Solvent Extraction Systems FCR&D work package. The report summarizes our initial considerations of potential influences that non-ideal chemistry may impose on computational prediction of outcomes in solvent extraction systems. The report is packaged into three separate test cases where a robustness of the prediction by SXFIT program is under scrutiny. The computational exercises presented here emphasize the importance of accurate representation of both an aqueous and organic mixtures when modeling liquid-liquid distribution systems. Case No.1 demonstrates that non-ideal behavior of HDEHP in aliphatic diluents, such as n-dodecane, interferes with the computation. Cases No.2 and No.3 focus on the chemical complexity of aqueous electrolyte mixtures. Both exercises stress the need for an improved thermodynamic model of an aqueous environment present in the europium distribution experiments. Our efforts for year 2 of this project will focus on the improvements of aqueous and non-aqueous solution models using fundamental physical properties of mixtures acquired experimentally in our laboratories.

  11. Solvents, Ethanol, Car Crashes and Tolerance: How Risky is Inhalation of Organic Solvents?

    Science.gov (United States)

    A research program in the National Health and Environmental Effects Research Laboratory of the U.S. EPA has led to some surprising considerations regarding the potential hazard of exposure to low concentrations of solvent vapors. This program involved conducting experiments to ch...

  12. Solvent sorting in (mixed solvent + electrolyte) systems: Time-resolved fluorescence measurements and theory

    Indian Academy of Sciences (India)

    Harun Al Rasidgazi; Hemant K Kashyap; Ranjit Biswas

    2015-01-01

    In this manuscriptwe explore electrolyte-induced modification of preferential solvation of a dipolar solute dissolved in a binary mixture of polar solvents. Composition dependence of solvation characteristics at a fixed electrolyte concentration has been followed. Binary mixtures of two different polarities have been employed to understand the competition between solute-ion and solute-solvent interactions. Time-resolved fluorescence Stokes shift and anisotropy have been measured for coumarin 153 (C153) in moderately polar (ethyl acetate + 1-propanol) and strongly polar (acetonitrile + propylene carbonate) binary mixtures at various mixture compositions, and in the corresponding 1.0M solutions of LiClO4. Both the mixtures show red shifts in C153 absorption and fluorescence emission upon increase of mole fraction of the less polar solvent component in presence of the electrolyte. In addition, measured average solvation times become slower and rotation times faster for the above change in the mixture composition. A semi-molecular theory based on solution density fluctuations has been developed and found to successfully capture the essential features of the measured Stokes shift dynamics of these complex multi-component mixtures. Dynamic anisotropy results have been analyzed by using both Stokes-Einstein-Debye (SED) and Dote-Kivelson-Schwartz (DKS) theories. The importance of local solvent structure around the dissolved solute has been stressed.

  13. Physicochemical and catalytic properties of Au nanorods micro-assembled in solvents of varying dipole moment and refractive index

    Energy Technology Data Exchange (ETDEWEB)

    Kaur, Rupinder; Pal, Bonamali, E-mail: bpal@thapar.edu

    2015-02-15

    Highlights: • Physicochemical activities of Au nanorods in water largely differ from organic solvents. • Au nanorods agglomeration increased with dipole moments of different polar solvents. • Refractive indexes of Au nanorods dispersion in various polar solvents are enhanced. • Electrokinetics significantly altered depending on agglomerated size of Au nanorods. • Catalysis or co-catalysis activity is varied as per the extent of Au nanorods coagulation. - Abstract: This paper deals with the impact of dipole moment (1.66–3.96 D) and refractive index (1.333–1.422) of the dispersion solvent on the plasmon absorption, surface charge, zeta potential, and adsorption properties of Au nanorods (AuNRs). AuNRs (length ≈ 53 nm and width ≈ 20 nm) undergo agglomeration (size 50–180 nm) with increase in the dipole moment of solvent (iPrOH < MeOH < DMF < DMSO). Whereas, no such coagulation occurs in H{sub 2}O and CCl{sub 4} suspension as confirmed by DLS and TEM size distribution. The electrostatic interaction of AuNRs with its surface adsorbed solvent dipoles leads to alteration of the their ionic state, absolute electronic charge and zeta potential (+49.79 mV in H{sub 2}O, +8.99 mV in DMF and −4.65 mV in MeOH dispersion) to a greater extent. This interaction distinctly modifies the adsorption behavior of polar molecules like p-nitrophenol and salicylic acid on AuNRs surface, as evidenced by the measured changes in their electro-kinetic parameters. As a result, we observe a substantial difference in catalytic and co-catalytic activities of AuNRs dispersed in various solvents as mentioned above because the catalytic properties of AuNRs are strongly dependent on the type of solvent in which they are dispersed.

  14. RESEARCH SPECIFIC FLUX OF SOLVENT IN THE PROCESSES OF ULTRAFILTRATION AND REVERSE OSMOSIS OF BIOLOGICAL SOLUTIONS SEPARATION IN BIOCHEMICAL INDUSTRY

    Directory of Open Access Journals (Sweden)

    S. I. Lazarev

    2015-01-01

    Full Text Available This work is devoted to the study of specific solvent stream in baro membrane separation processes in the biochemical industry. The main indicators, which characterize baromembranes technology, are productivity and quality division. Performance of baromembrane separation is estimated by the specific output or specific solvent stream, which is equal to the permeate flow per unit working area of the membrane per unit of time, and also determines the speed of the process of baromembrane division. This parameter depends on the material of the membrane, the nature of the solutes and their concentrations in the solution, the operating pressure, temperature and hydrodynamic processes. The article analyzed the specific solvent flow, which mathematically described by the equation based on Darcy's Law. This law establishes proportional dependence on the driving force of the process, the concentration and type of membrane. For the research was used following technique. The initial stage was to preliminary cleaning of membranes from impurities, checking the integrity of individual units, launching in work mode for a time period of 18 hours. Then there was a preliminary experience for the establishment of a permanent performance with a factor of retention membranes. After that was done a series of basic experiments, the results of which were used for calculate of specific solvent stream. As a result of investigations made certain conclusions. Specific solvent stream decreases with increasing concentration. In ultrafiltration membranes the specific solvent stream is higher than in reverse osmosis membranes. This phenomenon depends on the type of membrane. When the pressure increases the flow of the solvent and performance of baromembrane separation of solutions increases too. Specific solvent stream are influenced by concentrating polarization, gelation and sedimentation, which are formed as a result of increasing pressure and adsorption on the membrane

  15. Response Surface Optimization of Rotenone Using Natural Alcohol-Based Deep Eutectic Solvent as Additive in the Extraction Medium Cocktail

    Directory of Open Access Journals (Sweden)

    Zetty Shafiqa Othman

    2017-01-01

    Full Text Available Rotenone is a biopesticide with an amazing effect on aquatic life and insect pests. In Asia, it can be isolated from Derris species roots (Derris elliptica and Derris malaccensis. The previous study revealed the comparable efficiency of alcohol-based deep eutectic solvent (DES in extracting a high yield of rotenone (isoflavonoid to binary ionic liquid solvent system ([BMIM]OTf and organic solvent (acetone. Therefore, this study intends to analyze the optimum parameters (solvent ratio, extraction time, and agitation rate in extracting the highest yield of rotenone extract at a much lower cost and in a more environmental friendly method by using response surface methodology (RSM based on central composite rotatable design (CCRD. By using RSM, linear polynomial equations were obtained for predicting the concentration and yield of rotenone extracted. The verification experiment confirmed the validity of both of the predicted models. The results revealed that the optimum conditions for solvent ratio, extraction time, and agitation rate were 2 : 8 (DES : acetonitrile, 19.34 hours, and 199.32 rpm, respectively. At the optimum condition of the rotenone extraction process using DES binary solvent system, this resulted in a 3.5-fold increase in a rotenone concentration of 0.49 ± 0.07 mg/ml and yield of 0.35 ± 0.06 (%, w/w as compared to the control extract (acetonitrile only. In fact, the rotenone concentration and yield were significantly influenced by binary solvent ratio and extraction time (P<0.05 but not by means of agitation rate. For that reason, the optimal extraction condition using alcohol-based deep eutectic solvent (DES as a green additive in the extraction medium cocktail has increased the potential of enhancing the rotenone concentration and yield extracted.

  16. Differentiation of Chemical Components in a Binary Solvent Vapor Mixture Using Carbon/Polymer Composite-Based Chemiresistors

    Energy Technology Data Exchange (ETDEWEB)

    Patel, Sanjay V.; Jenkins, Mark W.; Hughes, Robert C.; Yelton, W. Graham; Ricco, Antonio J.

    1999-07-19

    We demonstrate a ''universal solvent sensor'' constructed from a small array of carbon/polymer composite chemiresistors that respond to solvents spanning a wide range of Hildebrand volubility parameters. Conductive carbon particles provide electrical continuity in these composite films. When the polymer matrix absorbs solvent vapors, the composite film swells, the average separation between carbon particles increases, and an increase in film resistance results, as some of the conduction pathways are broken. The adverse effects of contact resistance at high solvent concentrations are reported. Solvent vapors including isooctane, ethanol, dlisopropyhnethylphosphonate (DIMP), and water are correctly identified (''classified'') using three chemiresistors, their composite coatings chosen to span the full range of volubility parameters. With the same three sensors, binary mixtures of solvent vapor and water vapor are correctly classified, following classification, two sensors suffice to determine the concentrations of both vapor components. Polyethylene vinylacetate and polyvinyl alcohol (PVA) are two such polymers that are used to classify binary mixtures of DIMP with water vapor; the PVA/carbon-particle-composite films are sensitive to less than 0.25{degree}A relative humidity. The Sandia-developed VERI (Visual-Empirical Region of Influence) technique is used as a method of pattern recognition to classify the solvents and mixtures and to distinguish them from water vapor. In many cases, the response of a given composite sensing film to a binary mixture deviates significantly from the sum of the responses to the isolated vapor components at the same concentrations. While these nonlinearities pose significant difficulty for (primarily) linear methods such as principal components analysis, VERI handles both linear and nonlinear data with equal ease. In the present study the maximum speciation accuracy is achieved by an array

  17. DFT-based simulations of amide I' IR spectra of a small protein in solution using empirical electrostatic map with a continuum solvent model.

    Science.gov (United States)

    Welch, William R W; Kubelka, Jan

    2012-09-01

    A continuum solvent model was tested for simulations of amide I' IR spectra for a 40-residue subdomain of P22 viral coat protein in aqueous solution. Spectra obtained using DFT (BPW91/6-31G**) parameters for a reduced all-Ala representation of the protein were corrected by an electrostatic potential map obtained from the solvent cavity surface and AMBER99 side-chain atom partial charges. Various cavity sizes derived from van der Waals atomic radii with an added effective solvent radius up to 2.0 Å were tested. The interplay of the side-chain and solvent electrostatic effects was investigated by considering the side chains and solvent separately as well as together. The sensitivity to side-chain conformational fluctuations and to the parametrization of C(β) group partial charges was also tested. Simulation results were compared to the experimental amide I' spectra of P22 subdomain, including two (13)C isotopically edited variants, as well as to the previous simulations based on the molecular dynamics trajectory in explicit solvent. For small cavity sizes, between van der Waals and that with added solvent radius of 0.5 Å, better qualitative agreement with experiment was obtained than with the explicit solvent representation, in particular for the (13)C-labeled spectra. Larger protein cavities led to progressively worse predictions due to increasingly stronger electrostatic effects of side chains, which could no longer be well compensated for by the solvent potential. Balance between side-chain and solvent electrostatic effects is important in determining the width and shape of the simulated amide I', which is also virtually unaffected by side-chain-geometry fluctuations. The continuum solvent model combined with the electrostatic map is a computationally efficient and potentially robust approach for the simulations of IR spectra of proteins in solution.

  18. Reactivity of Imidazole Derivatives toward Phosphate Triester in DMSO/Water Mixtures: A Comprehensive Study on the Solvent Effect.

    Science.gov (United States)

    Campos, Renan B; Santos, Everton H; Oliveira, Alfredo R M; Ocampos, Fernanda Maria Marins; Souza, Bruno S; Barison, Andersson; Orth, Elisa S

    2015-08-07

    Many imidazole (IMZ) derivatives of pharmaceutical interest, which are potentially catalytic in dephosphorylation reactions, are soluble solely in mixtures of water and organic solvent. In order to understand these poorly explored reactions and properly compare them, a thorough study related to solvent effects for the analogous spontaneous reaction and with common IMZ derivatives is necessary, which is lacking in the literature. Herein, we report a quantitative solvent effect analysis in DMSO/water mixtures for (i) the hydrolysis reaction of diethyl 2,4-dinitrophenylphosphate (DEDNPP) and (ii) the nucleophilic reaction of IMZ and 1-methylimidazole (MEI) with DEDNPP. The solvent effect was fitted satisfactorily with multiple regression analysis, correlating the obtained second-order rate constants with solvent parameters such as acidity, basicity, and polarity/polarizability from Catalán's scale. The contribution of these parameters can be taken into account to elucidate the reactivity in these media. Interestingly, IMZ is more reactive than MEI in DMSO, compared to water alone, which is attributed to the availability of hydrogen-bond formation. Nuclear magnetic resonance spectroscopy ((1)H, (13)C, and (31)P), mass spectrometry, thermodynamic analysis, and density functional theory calculations were carried out to corroborate the proposed nucleophilic mechanism.

  19. Growth and Solvent Effects of a Promising Nonlinear Optical Sodium Paranitrophenolate Dihydrate (NO2-C6H4-ONa·2H2O) Single Crystal

    Institute of Scientific and Technical Information of China (English)

    B.Milton Boaz; A.Leyo Rajesh; S. Xavier Jesu Raja; S. Jerome Das

    2004-01-01

    Sodium paranitrophenolate dihydrate (NPNa·2H2O) is an excellent semiorganic nonlinear optical (NLO) material, crystallizes both in water and methanol with high degree of transparency. Good optical quality single crystals of dimension upto 18 mmx6 mmx3 mm are obtained by isothermal solvent evaporation technique. The solubility of the crystal in different solvents was measured gravimetrically. The single crystals of NPNa·2H2O show variation in physical properties and growth rate in different solvents. Methanol or ethanol solution yields crystals of bipyramidal shape with clear morphology. However, methanol grown crystal is exhibiting improved hardness parameters and possesses excellent thermal stability as compared to water grown crystals. The effects of solvent on hardness parameter along with thermal and optical properties of NPNa·2H2O was revealed in this paper.

  20. Stochastic level-set variational implicit-solvent approach to solute-solvent interfacial fluctuations.

    Science.gov (United States)

    Zhou, Shenggao; Sun, Hui; Cheng, Li-Tien; Dzubiella, Joachim; Li, Bo; McCammon, J Andrew

    2016-08-01

    Recent years have seen the initial success of a variational implicit-solvent model (VISM), implemented with a robust level-set method, in capturing efficiently different hydration states and providing quantitatively good estimation of solvation free energies of biomolecules. The level-set minimization of the VISM solvation free-energy functional of all possible solute-solvent interfaces or dielectric boundaries predicts an equilibrium biomolecular conformation that is often close to an initial guess. In this work, we develop a theory in the form of Langevin geometrical flow to incorporate solute-solvent interfacial fluctuations into the VISM. Such fluctuations are crucial to biomolecular conformational changes and binding process. We also develop a stochastic level-set method to numerically implement such a theory. We describe the interfacial fluctuation through the "normal velocity" that is the solute-solvent interfacial force, derive the corresponding stochastic level-set equation in the sense of Stratonovich so that the surface representation is independent of the choice of implicit function, and develop numerical techniques for solving such an equation and processing the numerical data. We apply our computational method to study the dewetting transition in the system of two hydrophobic plates and a hydrophobic cavity of a synthetic host molecule cucurbit[7]uril. Numerical simulations demonstrate that our approach can describe an underlying system jumping out of a local minimum of the free-energy functional and can capture dewetting transitions of hydrophobic systems. In the case of two hydrophobic plates, we find that the wavelength of interfacial fluctuations has a strong influence to the dewetting transition. In addition, we find that the estimated energy barrier of the dewetting transition scales quadratically with the inter-plate distance, agreeing well with existing studies of molecular dynamics simulations. Our work is a first step toward the inclusion of

  1. Effect of some organic solvents on oxidative phosphorylation in rat liver mitochondria: Choice of organic solvents.

    Science.gov (United States)

    Syed, Muzeeb; Skonberg, Christian; Hansen, Steen Honoré

    2013-12-01

    The effect of acetone, acetonitrile, dimethyl sulfoxide (DMSO), ethanol and methanol on oxidative phosphorylation (ATP synthesis) in rat liver mitochondria has been studied. All the organic solvents inhibited the oxidative phosphorylation in a concentration dependent manner, but with differences in potencies. Among the tested organic solvents, acetonitrile and acetone were more potent than ethanol, methanol, and DMSO. There was no significant difference in oxidative phosphorylation, compared to controls, when the concentrations of acetone was below 1% (v/v), of acetonitrile below 2% (v/v), of DMSO below 10% (v/v), of ethanol below 5% or of methanol below 2%, respectively. There was complete inhibition of oxidative phosphorylation at 50% (v/v) of acetone, acetonitrile and ethanol. But in the case of DMSO and methanol there were some residual activities observed at the 50% concentration level. DMSO showed least effect on oxidative phosphorylation with an IC50 value of 13.3±1.1% (v/v), followed by methanol (IC50 value 8.3±1.0), ethanol (IC50 value 4.6±1.1), acetone (IC50 value 4.3±1.0) and finally acetonitrile (IC50 value 2.1±1.0). All the organic solvents showed modulatory effects on 2,4-dinitrophenol (DNP) mediated inhibition of oxidative phosphorylation with potentiation of the action of DNP. Acetonitrile showed the highest potentiation effect followed by acetone, ethanol, methanol, and DMSO in presence of DNP. The use of organic solvents for investigation of the effects of compounds on oxidative phosphorylation in mitochondria should therefore include the use of relevant concentrations of the organic solvent in order to validate the contribution.

  2. Simple measurements for prediction of drug release from polymer matrices - Solubility parameters and intrinsic viscosity.

    Science.gov (United States)

    Madsen, Claus G; Skov, Anders; Baldursdottir, Stefania; Rades, Thomas; Jorgensen, Lene; Medlicott, Natalie J

    2015-05-01

    This study describes how protein release from polymer matrices correlate with simple measurements on the intrinsic viscosity of the polymer solutions used for casting the matrices and calculations of the solubility parameters of polymers and solvents used. Matrices of poly(dl-lactide-co-glycolide) (PLGA) were cast with bovine serum albumin (BSA) as a model drug using different solvents (acetone, dichloromethane, ethanol and water). The amount of released protein from the different matrices was correlated with the Hildebrand and Hansen solubility parameters of the solvents, and the intrinsic viscosity of the polymer solutions. Matrix microstructure was investigated by transmission and scanning electron microscopy (TEM and SEM). Polycaprolactone (PCL) matrices were used in a similar way to support the results for PLGA matrices. The maximum amount of BSA released and the release profile from PLGA matrices varied depending on the solvent used for casting. The maximum amount of released BSA decreased with higher intrinsic viscosity, and increased with solubility parameter difference between the solvent and polymer used. The solvent used also had an effect on the matrix microstructure as determined by TEM and SEM. Similar results were obtained for the PCL polymer systems. The smaller the difference in the solubility parameter between the polymer and the solvent used for casting a polymer matrix, the lower will be the maximum protein release. This is because of the presence of smaller pore sizes in the cast matrix if a solvent with a solubility parameter close to the one of the polymer is used. Likewise, the intrinsic viscosity of the polymer solution increases as solubility parameter differences decrease, thus, simple measurements of intrinsic viscosity and solubility parameter difference, allow the prediction of protein release profiles. Copyright © 2015 Elsevier B.V. All rights reserved.

  3. Hansen solubility parameter analysis on the dispersion of zirconia nanocrystals.

    Science.gov (United States)

    Wang, Sho-Hsun; Liu, Jia-Hong; Pai, Chin-Tung; Chen, Chien-Wei; Chung, Pao-Tang; Chiang, Anthony Shiaw-Tseh; Chang, Shinn-Jen

    2013-10-01

    Nanoparticle dispersible in a broad range of solvents is desirable when preparing an organic/inorganic nanocomposite. In this report, the dispersion behavior of carboxylate-grafted zirconia nanoparticle in 25 solvents covering a wide range of polarity was analyzed based on their Hansen solubility parameters (HSP). Particles grafted with alkyl-chain longer than four carbons could only be dispersed in non-polar solvents, while that grafted with acetic acid was dispersible in polar ones. However, particle modified with methacrylic acid (MA) was compatible with both types of solvents, which was rather unexpected. Further NMR analysis showed that the carboxylate-grafted samples contained a trace amount of triethanolamine (TEA) due to the particular ZrO2 synthesis process employed. The combination of the hydrophilic TEA ligand with the short hydrophobic tail of methacrylate broadened the range of compatible solvents from benzene to methanol. Such an extended solvent compatibility was observed previously only for nanoparticles covered with large polymer surfactants having both hydrophilic and hydrophobic groups. Achieving this with two small molecules having separate functional groups is crucial when one needs to maximize the inorganic content in a composite.

  4. A new solvent suppression method via radiation damping effect

    Institute of Scientific and Technical Information of China (English)

    Cui Xiao-Hong; Peng Ling; Zhang Zhen-Min; Cai Shu-Hui; Chen Zhong

    2011-01-01

    Radiation damping effects induced by the dominated solvent in a solution sample can be applied to suppress the solvent signal.The precession pathway and rate back to equilibrium state between solute and solvent spins are different under radiation damping.In this paper,a series of pulse sequences using radiation damping were designed for the solvent suppression in nuclear magnetic resonance (NMR) spectroscopy.Compared to the WATERGATE method,the solute signals adjacent to the solvent would not be influenced by using the radiation damping method.The one-dimensional (1D) 1H NMR,two-dimensional (2D) gCOSY,and J-resolved experimental results show the practicability of solvent suppression via radiation damping effects in 1D and 2D NMR spectroscopy.

  5. GREEN TECHNIQUE-SOLVENT FREE SYNTHESIS AND ITS ADVANTAGES

    Directory of Open Access Journals (Sweden)

    M.Himaja

    2011-04-01

    Full Text Available Green Chemistry, the design of chemical products and processes that reduce or eliminate the use and generation of hazardous substances is an overarching approach that is applicable to all aspects of chemistry. All synthetic processes involve the use of different solvents. Unfortunately many of the solvents are used in industry and retail are volatile organic compounds (VOCs which lead to environmental damage, through pollution, risks to human health and to resource depletion, we need to develop and apply more environmentally friendly approaches. So, all traditional and old synthetic routes obviously give adverse effects to the mankind and all living beings. Green chemistry provides “Green” paths for different synthetic routes using non-hazardous solvents and environmental- friendly chemicals. Solvent free synthesis has several advantages over the classical method of synthesis. Due to enormous advantages of solvent free reactions, new solvent-free approaches are being discovered for eco-friendly synthesis of many compounds.

  6. Influence of processing procedure on the quality of Radix Scrophulariae: a quantitative evaluation of the main compounds obtained by accelerated solvent extraction and high-performance liquid chromatography.

    Science.gov (United States)

    Cao, Gang; Wu, Xin; Li, Qinglin; Cai, Hao; Cai, Baochang; Zhu, Xuemei

    2015-02-01

    An improved high-performance liquid chromatography with diode array detection combined with accelerated solvent extraction method was used to simultaneously determine six compounds in crude and processed Radix Scrophulariae samples. Accelerated solvent extraction parameters such as extraction solvent, temperature, number of cycles, and analysis procedure were systematically optimized. The results indicated that compared with crude Radix Scrophulariae samples, the processed samples had lower contents of harpagide and harpagoside but higher contents of catalpol, acteoside, angoroside C, and cinnamic acid. The established method was sufficiently rapid and reliable for the global quality evaluation of crude and processed herbal medicines.

  7. Σpider diagram: a universal and versatile approach for system comparison and classification: application to solvent properties.

    Science.gov (United States)

    Lesellier, E

    2015-04-10

    Classification methods based on physico-chemical properties are very useful in analytical chemistry, both for extraction and separation processes. Depending on the number of parameters, several classification approaches can be used: by plotting two- or three-dimensional maps (triangles, cubes, spheres); by calculating comparison values for one system with reference to another one, i.e. the ranking factor F, or the Neue selectivity difference s(2); or with chemometric methods (principal component analysis-PCA or hierarchical cluster analysis-HCA). All these methods display advantages and drawbacks: some of them are limited by the number of studied parameters (e.g. three for triangle or sphere plots); others require a new calculation when changing the reference point (F; s(2)), while for chemometric methods (PCA, HCA), the relationships between the clusters and the physico-chemical properties are not always easily understandable. From previous studies performed in supercritical fluid chromatography for stationary phase classification on the basis of linear solvation energy relationships (LSER) including five parameters, we developed a classification map called the Σpider diagram. This diagram allows plotting in a two-dimensional map the location of varied systems, having as many parameters as the ones required getting a satisfactory classification. It can be three, five, eight, or any number. In the present paper, we apply this diagram, and the calculation mode to obtain this diagram, to different solvent classifications: Snyder triangle, solvatochromic solvent selectivity, Hansen parameters, and also to LSER Abraham descriptors and COSMO-RS parameters. The new figure based on Snyder data does not change the global view of groups, except by the use of corrected data from literature, and allows adding the polarity value onto the map. For the solvatochromic solvent selectivity, it leads to achieve a better view of solvents having no acidic character. For Hansen

  8. Deep eutectic solvents: sustainable media for nanoscale and functional materials.

    Science.gov (United States)

    Wagle, Durgesh V; Zhao, Hua; Baker, Gary A

    2014-08-19

    Deep eutectic solvents (DESs) represent an alternative class of ionic fluids closely resembling room-temperature ionic liquids (RTILs), although, strictly speaking, they are distinguished by the fact that they also contain an organic molecular component (typically, a hydrogen bond donor like a urea, amide, acid, or polyol), frequently as the predominant constituent. Practically speaking, DESs are attractive alternatives to RTILs, sharing most of their remarkable qualities (e.g., tolerance to humidity, negligible vapor pressure, thermostability, wide electrochemical potential windows, tunability) while overcoming several limitations associated with their RTIL cousins. Particularly, DESs are typically, less expensive, more synthetically accessible (typically, from bulk commodity chemicals using solvent/waste-free processes), nontoxic, and biodegradable. In this Account, we provide an overview of DESs as designer solvents to create well-defined nanomaterials including shape-controlled nanoparticles, electrodeposited films, metal-organic frameworks, colloidal assemblies, hierarchically porous carbons, and DNA/RNA architectures. These breakthroughs illustrate how DESs can fulfill multiple roles in directing chemistry at the nanoscale: acting as supramolecular template, metal/carbon source, sacrificial agent (e.g., ammonia release from urea), and/or redox agent, all in the absence of formal stabilizing ligand (here, solvent and stabilizer are one and the same). The ability to tailor the physicochemical properties of DESs is central to controlling their interfacial behavior. The preorganized "supramolecular" nature of DESs provides a soft template to guide the formation of bimodal porous carbon networks or the evolution of electrodeposits. A number of essential parameters (viscosity, polarity, surface tension, hydrogen bonding), plus coordination with solutes/surfaces, all play significant roles in modulating species reactivity and mass transport properties governing the

  9. A new method to determine the partial solubility parameters of polymers from intrinsic viscosity.

    Science.gov (United States)

    Bustamante, Pilar; Navarro-Lupión, Javier; Escalera, Begoña

    2005-02-01

    A modification of the extended Hansen method, formerly used to determine the partial solubility parameters of drugs and non-polymeric excipients is tested with a polymer for the first time. The proposed method relates the logarithm of the intrinsic viscosities of the polymer in a series of solvents and solvent mixtures with the Hansen (three parameter model) and Karger (four parameter model) partial solubility parameters. The viscosity of diluted solutions of hydroxypropyl methylcellulose (HPMC) was determined in pure solvents and binary mixtures of varying polarity. The intrinsic viscosity was obtained from the common intercept of the Huggins and Kraemer relationships. The intrinsic viscosity tends to increase with increasing the solubility parameter of the medium. The results show that hydrogen bonding and polarity of the polymer largely determine polymer-solvent interactions. The models proposed provided reasonable partial and total solubility parameters for the polymer and enable one to quantitatively characterize, for the first time, the Lewis acid-base ability of a polymer thus, providing a more realistic picture of hydrogen bonding for solvent selection/compatibility and to predict drug-polymer interactions. Combination of the dispersion and polar parameters into a single non-specific solubility parameter was also tested. The results extend earlier findings and suggest that the models are quite versatile and may be applied to drugs, non-polymeric and polymeric excipients.

  10. Hot and cold water as a supercritical solvent

    Science.gov (United States)

    Fuentevilla, Daphne Anne

    This dissertation addresses the anomalous properties of water at high temperatures near the vapor-liquid critical point and at low temperatures in the supercooled liquid region. The first part of the dissertation is concerned with the concentration dependence of the critical temperature, density, and pressure of an aqueous sodium chloride solution. Because of the practical importance of an accurate knowledge of critical parameters for industrial, geochemical, and biological applications, an empirical equation for the critical locus of aqueous sodium chloride solutions was adopted in 1999 by the International Association for the Properties of Water and Steam (IAPWS) as a guideline. However, since this original Guideline on the Critical Locus of Aqueous Solutions of Sodium Chloride was developed, two new theoretical developments occurred, motivating the first part of this dissertation. Here, I present a theory-based formulation for the critical parameters of aqueous sodium chloride solutions as a proposed replacement for the empirical formulation currently in use. This formulation has been published in the International Journal of Thermophysics and recommended by the Executive Committee of IAPWS for adoption as a Revised Guideline on the Critical Locus of Aqueous Solutions of Sodium Chloride. The second part of the dissertation addresses a new concept, considering cold water as a supercritical solvent. Based on the idea of a second, liquid-liquid, critical point in supercooled water, we explore the possibility of supercooled water as a novel supercooled solvent through the thermodynamics of critical phenomena. In 2006, I published a Physical Review letter presenting a parametric scaled equation of state for supercooled-water. Further developments based on this work led to a phenomenological mean-field "two-state" model, clarifying the nature of the phase separation in a polyamorphic single-component liquid. In this dissertation, I modify this two-state model to

  11. Terpenes as Green Solvents for Extraction of Oil from Microalgae

    OpenAIRE

    Celine Dejoye Tanzi; Maryline Abert Vian; Christian Ginies; Mohamed Elmaataoui; Farid Chemat

    2012-01-01

    Herein is described a green and original alternative procedure for the extraction of oil from microalgae. Extractions were carried out using terpenes obtained from renewable feedstocks as alternative solvents instead of hazardous petroleum solvents such as n-hexane. The described method is achieved in two steps using Soxhlet extraction followed by the elimination of the solvent from the medium using Clevenger distillation in the second step. Oils extracted from microalgae...

  12. Modeling post-combustion CO2 capture with amine solvents

    OpenAIRE

    Léonard, Grégoire; Heyen, Georges

    2010-01-01

    In order to avoid the emission of large amounts of greenhouse gas, CO2 capture in fossil fuel power plants and subsequent underground CO2 sequestration is studied. The capture occurs by reactive CO2 absorption into chemical solvent systems at moderate temperature (~50°C) followed by solvent regeneration at higher temperature (~120°C). So far, the most employed solvent for acid gas capture is monoethanolamine (MEA). One main drawback of this technology is the high energy consumption necessary ...

  13. Alcohols as hydrogen-donor solvents for treatment of coal

    Science.gov (United States)

    Ross, David S.; Blessing, James E.

    1981-01-01

    A method for the hydroconversion of coal by solvent treatment at elevated temperatures and pressure wherein an alcohol having an .alpha.-hydrogen atom, particularly a secondary alcohol such as isopropanol, is utilized as a hydrogen donor solvent. In a particular embodiment, a base capable of providing a catalytically effective amount of the corresponding alcoholate anion under the solvent treatment conditions is added to catalyze the alcohol-coal reaction.

  14. Solvent effects on enzymes - Implications for extraterrestrial life.

    Science.gov (United States)

    Heinrich, M. R.

    1972-01-01

    Review of several studies on the alterations taking place in the structure, catalytic activity, specificity, and stability of an enzyme when some or all of the water in the medium is replaced by another solvent. These studies show the utility of solvents as a tool for probing enzyme function. They also suggest that solvents other than water should be investigated as media for controlling and directing enzyme reactions.

  15. Solvent effect modelling of isocyanuric products synthesis by chemometric methods

    OpenAIRE

    Havet, Jean-Louis; Billiau-Loreau, Myriam; Porte, Catherine; Delacroix, Alain

    2002-01-01

    Chemometric tools were used to generate the modelling of solvent e¡ects on the N-alkylation of an isocyanuric acid salt. The method proceeded from a central composite design applied on the Carlson solvent classification using principal components analysis. The selectivity of the reaction was studied from the production of different substituted isocyanuric derivatives. Response graphs were obtained for each compound and used to devise a strategy for solvent selection. The prediction models wer...

  16. Relationship between swelling of hydroxypropylmethylcellulose and the Hansen and Karger partial solubility parameters.

    Science.gov (United States)

    Navarro-Lupión, Francisco-Javier; Bustamante, Pilar; Escalera, Begoña

    2005-07-01

    A model that relates the equilibrium swelling of hydroxypropylmethylcellulose to the partial solubility parameters of both the polymer and the solvents is proposed to interpret and correlate the experimental data. The non-specific interactions are expressed as the dispersion delta(d) and polar delta(p) solubility parameters of Hansen, or as a combination of both. Hydrogen bonding is represented by the acidic delta(a) and the basic delta(b) Karger solubility parameters. The results are compared with models including the same parameters for non-specific interactions (delta(d) and delta(p)) and the Hansen hydrogen bonding parameter delta(h). Equilibrium swelling of this hydrophilic polymer that is widely used in drug formulation is measured in pure solvents covering a wide polarity range. In a qualitative way, swelling increases in solvents with higher Hildebrand solubility parameters and stronger hydrogen bonding capability, and it decreases in non-polar solvents. Single polarity indexes, such as the Hildebrand solubility parameter or the partition coefficient (PC), do not fit well the overall experimental data. The best correlations were obtained with the proposed model, providing at the same time an interpretation consistent with the physical meaning of the terms included in the equation. Swelling increases as the non-specific interactions of the polymer and the solvents become alike, and as the Lewis acid-base interactions of the polymer (1) and the solvent (2) represented by the products delta(1a)delta(2b) and delta(1b)delta(2a) become greater. Conversely, hydrogen bonding self association of the solvents (the product delta(1a)delta(1b)) lowers swelling. The results show that the Karger hydrogen bonding parameters provide a better approach than the Hansen hydrogen bonding parameter to correlate the swelling behavior of a hydrophilic polymer. (c) 2005 Wiley-Liss, Inc.

  17. NMR microscopy of tissue in organic and mixed solvents

    Directory of Open Access Journals (Sweden)

    Macura Slobodan

    2013-01-01

    Full Text Available We propose to use organic and mixed solvents for nuclear magnetic resonance microscopy of fixed tissue as a means for improving image information content. NMR properties of some standard solvents (methanol, acetone, DMSO and solvents in use for tissue processing in pathology (xylenes, paraffin, ‘Clearify’ have been measured, reviewed, and analyzed. It was found that DMSO and paraffin are very useful solvents that provide images of better quality than those obtained in water (neutralized formalin buffer. This is illustrated on the formalin fixed mouse brain sections imaged at 16.4 teslas (700 MHz.

  18. Discrete solvent effects on the effective interaction between charged colloids

    CERN Document Server

    Allahyarov, E

    2000-01-01

    Using computer simulations of two charged colloidal spheres with their counterions in a hard sphere solvent, we show that the granular nature of the solvent significantly influences the effective colloidal interaction. For divalent counterions, the total effective force can become attractive generated by counterion hydration, while for monovalent counterions the forces are repulsive and well-described by a solvent-induced colloidal charge renormalization. Both effects are not contained in the traditional "primitive" approaches but can be accounted for in a solvent-averaged primitive model.

  19. The development of Gallstone solvent temperature adaptive PID control system

    Institute of Scientific and Technical Information of China (English)

    MA; BING; QIAO; BO; YAN

    2012-01-01

    The paper expatiated the work principle,general project,and the control part of the corresponding program of the temperature system in the gallstone dissolving instrument.Gallstone dissolving instrument adopts automatic control solvent cycle of direct solution stone treatment,replacing the traditional external shock wave rock row stone and gallblad-der surgery method.PID control system to realize the gall stone solvent temperature intelligent control,the basic principle of work is as solvent temperature below the set temperature,the relay control heater to solvent to be heated,conversely,no heating,achieve better able to dissolve the the rapeutic effect of gallstones.

  20. Efficiency of bulky protic solvent for SN2 reaction.

    Science.gov (United States)

    Lee, Sung-Sik; Kim, Ho-Sung; Hwang, Tae-Kyu; Oh, Young-Ho; Park, Sung-Woo; Lee, Sungyul; Lee, Byoung Se; Chi, Dae Yoon

    2008-01-03

    We calculate and compare the effects of aprotic vs protic solvent on the rate of SN2 reaction [F- + C3H7OMs--> C3H7F + OMs-]. We find that aprotic solvent acetonitrile is more efficient than a small protic solvent such as methanol. Bulky protic solvent (tert-butyl alcohol) is predicted to be quite efficient, giving the rate constant that is similar to that in CH3CN. Our calculated relative activation barriers of the SN2 reaction in methanol, tert-butyl alcohol, and CH3CN are in good agreement with experimental observations.

  1. A study of parameters affecting the solvent extraction of lactic acid from fermentation broth

    OpenAIRE

    Udachan,I. S.; Sahoo, A.K.

    2014-01-01

    Lactic acid has recently been drawing much interest as a raw material for biodegradable polymer. One of the promising technologies for recovery of lactic acid from fermentation broth is reactive liquid - liquid extraction. Equilibrium studies on the reactive extraction of lactic acid with trioctylamine (TOA) in various organic phases and its re-extraction into aqueous solutions were carried out. In this study distribution coefficient, extractability, stripping efficiency of various active and...

  2. A study of parameters affecting the solvent extraction of lactic acid from fermentation broth

    Directory of Open Access Journals (Sweden)

    I. S. Udachan

    2014-09-01

    Full Text Available Lactic acid has recently been drawing much interest as a raw material for biodegradable polymer. One of the promising technologies for recovery of lactic acid from fermentation broth is reactive liquid - liquid extraction. Equilibrium studies on the reactive extraction of lactic acid with trioctylamine (TOA in various organic phases and its re-extraction into aqueous solutions were carried out. In this study distribution coefficient, extractability, stripping efficiency of various active and inert diluents with TOA as extractant were investigated, which were higher for active diluents. The effects of operating temperature, speed of agitation, agitation time and diluent composition on extraction efficiency were also studied. Temperature and extraction efficiency were inversely proportional to each other, whereas extraction efficiency was little affected by speed of agitation and agitation time.

  3. A New Method for the Characterisation of Solutes and Solvent Phases Using Solvatochromic Parameters

    Science.gov (United States)

    1991-01-01

    propanoate 1.34 -074 -208 2.15 2.459 0.31Methyl butanoate 144 -11.50’ - 141) -2.84 2.08 2.943 086Methyl pentanoate 1 70 - 12.33’ -2.08 -378 1.88 3.442...6.69 -1.95 409 203 2 16 2.376 0.22Ethyl propanoate 159 -1.31 -2.90 1.97 2.881 091Ethyl butanoate I 77 - 1 99 -376 183 3.379 1.55Ethyl pentanoate 177...0.606 2.290 2954 Butanoic acid 0.00 0.241 0.210 0.60 2.820 0.54 0.42 0.747 2.830 2956 Pentanoic acid 0.00 0.247 0205 0.60 2.590 0.54 0.41 0.887 3.380

  4. Enzyme catalysis in organic solvents: influence of water content, solvent composition and temperature on Candida rugosa lipase catalyzed transesterification.

    Science.gov (United States)

    Herbst, Daniela; Peper, Stephanie; Niemeyer, Bernd

    2012-12-31

    In the present study the influence of water content, solvent composition and reaction temperature on the transesterification of 1-phenylpropan-2-ol catalyzed by Candida rugosa lipase was examined. Reactions were carried out in different mixtures of hexane and tetrahydrofurane. The studies showed that an increasing water content of the organic solvent results in an increasing enzyme activity and a decreasing enantiomeric excess. Furthermore, a significant influence of the solvent hydrophilicity both on the enzyme activity and on the enantiomeric excess was found. An increase in solvent hydrophilicity leads to a decrease of enzyme activity and an increase of the enantiomeric excess. This indicates that the enzyme becomes more selective with decreasing flexibility. Similar effects were found by variation of the reaction temperature. Taken together, the decrease in conversion and the increase in selectivity with increasing solvent hydrophilicity are induced by the different water contents on the enzyme surface and not by the solvent itself.

  5. Design of protonation constant measurement apparatus for carbon dioxide capturing solvents

    Science.gov (United States)

    Ma'mun, S.; Amelia, E.; Rahmat, V.; Alwani, D. R.; Kurniawan, D.

    2016-11-01

    Global warming phenomenon has led to world climate change caused by high concentrations of greenhouse gases (GHG), e.g. carbon dioxide (CO2), in the atmosphere. Carbon dioxide is produced in large amount from coal-fired power plants, iron and steel production, cement production, chemical and petrochemical manufacturing, natural gas purification, and transportation. Carbon dioxide emissions seem to rise from year to year; some efforts to reduce the emissions are, therefore, required. Amine-based absorption could be deployed for post-combustion capture. Some parameters, e.g. mass transfer coefficients and chemical equilibrium constants, are required for a vapor-liquid equilibrium modeling. Protonation constant (pKa), as one of those parameters, could then be measured experimentally. Therefore, an experimental setup to measure pKa of CO2 capturing solvents was designed and validated by measuring the pKa of acetic acid at 30 to 70 °C by a potentiometric titration method. The set up was also used to measure the pKa of MEA at 27 °C. Based on the validation results and due to low vapor pressure of CO2 capturing solvents in general, e.g. alkanolamines, the setup could therefore be used for measuring pKa of the CO2 capturing solvents at temperatures up to 70 °C.

  6. Field test results of the physical solvent N-Formyl morpholine for gas treating applications

    Energy Technology Data Exchange (ETDEWEB)

    Palla, N.; Lee, A.L.

    1997-12-31

    The Institute of Gas Technology (IGT) is developing gas processing technology that will reduce gas processing costs for current production and allow subquality gas to be economically produced that would have been otherwise, not produced. The experimental program has primarily focused on the evaluation of N-Formyl Morpholine (NFM) as a physical solvent for the cost-effective upgrading of subquality natural gas to pipeline quality. The selection of NFM for this program was based on previous work conducted by IGT in the selective removal of hydrogen sulfide, and carbon dioxide from coal gasifier effluents. That work showed that the use of NFM resulted in a significant cost advantage over 107 other solvents for that application. The project approach for the development of NFM process has been divided into following main categories: obtain vapor-liquid equilibrium, physical properties and additional published literature data; obtain mass-transfer coefficients using 2 inch absorber/stripper apparatus and calculate equation of state parameters and binary interaction parameters using VLE data; develop a gas processing model using Aspen Plus simulation program and evaluate economic advantages of the NFM process compared to commercial physical solvent; and design a pilot plant skid mounted field test unit and conduct field test experiments.

  7. Understanding dissolution behavior of 193nm photoresists in organic solvent developers

    Science.gov (United States)

    Lee, Seung-Hyun; Park, Jong Keun; Cardolaccia, Thomas; Sun, Jibin; Andes, Cecily; O'Connell, Kathleen; Barclay, George G.

    2012-03-01

    Herein, we investigate the dissolution behavior of 193-nm chemically amplified resist in different organic solvents at a mechanistic level. We previously reported the effect of solvent developers on the negative tone development (NTD) process in both dry and immersion lithography, and demonstrated various resist performance parameters such as photospeed, critical dimension uniformity, and dissolution rate contrast are strongly affected by chemical nature of the organic developer. We further pursued the investigation by examining the dependence of resist dissolution behavior on their solubility properties using Hansen Solubility Parameter (HSP). The effects of monomer structure, and resist composition, and the effects of different developer chemistry on dissolution behaviors were evaluated by using laser interferometry and quartz crystal microbalance. We have found that dissolution behaviors of methacrylate based resists are significantly different in different organic solvent developers such as OSDTM-1000 Developer* and n-butyl acetate (nBA), affecting their resist performance. This study reveals that understanding the resist dissolution behavior helps to design robust NTD materials for higher resolution imaging.

  8. Organogels thermodynamics, structure, solvent role, and properties

    CERN Document Server

    Guenet, Jean-Michel

    2016-01-01

    This book provides a physics-oriented introduction to organogels with a comparison to polymer thermoreversible gels whenever relevant. The past decade has seen the development of a wide variety of newly-synthesized molecules that can spontaneously self-assemble or crystallize from their organic or aqueous solutions to produce fibrillar networks, namely organogels, with potential applications in organic electronics, light harvesting, bio-imaging, non-linear optics, and the like. This compact volume presents a detailed outlook of these novel molecular systems with special emphasis upon their thermodynamics, morphology, molecular structure, and rheology. The definition of these complex systems is also tackled, as well as the role of the solvent. The text features numerous temperature-phase diagrams for a variety of organogels as well as illustrations of their structures at the microscopic, mesoscopic and macroscopic level. A review of some potential applications is provided including hybrid functional materials ...

  9. Solvent control of intramolecular proton transfer

    DEFF Research Database (Denmark)

    Manolova, Y.; Marciniak, Heinz; Tschierlei, S.

    2017-01-01

    The solvent dependent excited state dynamics of 4-hydroxy-3-(piperidin-1-ylmethyl)-1-naphthaldehyde (compound 2), a candidate for a molecular switch based on intramolecular proton transfer, was investigated by ultrafast spectroscopy and quantum-chemical calculations. In acetonitrile a mixture...... of molecules in the enol and zwitterionic proton transfer (PT) form exists in the ground state. However, the zwitterion is the energetically favored one in the electronically excited state. Optical excitation of the enol form results in intramolecular proton transfer and formation of the PT form within 1.4 ps....... In addition we observe the appearance of a long living species with a rate of 1/(330 ps) which returns to the original ground state on time scales beyond 2 ns and which is attributed to the triplet state. In toluene the enol form is the only observed ground state tautomer, but no light induced proton transfer...

  10. Solvent Extraction in Hydrometallurgy: Present and Future

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    During the past 10 years, there have been incremental advances in the application of solvent extraction to process hydrometallurgy. The most cited areas in the literature include chemistry, chemical engineering, pilot plants, and plant operation. Within these areas, there were considerable interest in synergism,diluents, degradation, contactors, surfactants, hydrometallurgical applications, environmental and secondary applications, and health and safety. The summary to the present is followed by a prediction for the future in the above areas of interest. These include the use of speciation; improved understanding of the role of surfactants on the system; optimization through modelling, pilot plants, and contactor selection; improvements in plant operation; further new applications; and plant safety. The review has indicated that considerable knowledge is now available to optimize and improve on process design and plant applications.

  11. Investigation of the dispersion behavior of fluorinated MWCNTs in various solvents.

    Science.gov (United States)

    Liu, Yang; Zhang, Yichun; Wang, Zaoming; Lai, Wenchuan; Zhang, Xiaojiao; Wang, Xu; Liu, Xiangyang

    2017-08-16

    The investigation of the dispersion behavior of fluorinated MWCNTs (F-MWCNTs) is very important to understand their structure and take full advantage of their good properties. In this present paper, the dispersion behavior of F-MWCNTs with a low content and a high content of fluorine (denoted as lF-MWCNTs and hF-MWCNTs) was explored in 18 kinds of common solvents. The surface of hF-MWCNTs is considered to be a heterostructure consisting of fluorinated regions and aromatic regions, while lF-MWCNTs are inclined to be a homogeneous structure on the basis of their dispersion behavior. According to dispersion theory based on surface energy and Hansen solubility parameters (HSPs), it was indicated that the corresponding preferable solvents are different for different regions. As a result, good solvents of hF-MWCNTs are distributed in a quite wide scope while lF-MWCNTs can be dispersed only in a significantly narrow range of solvents. The HSPs of lF-MWCNTs and hF-MWCNTs are determined to be δD = 17.6 MPa(1/2), δP = 11.8 MPa(1/2), δH = 8.8 MPa(1/2) and δD = 16.9 MPa(1/2), δP = 9.3 MPa(1/2), δH = 13.5 MPa(1/2), respectively. As a result, mixed solvents of acetone and water were carefully tuned to be compatible with hF-MWCNTs. The dispersion behaviors of lF-MWCNTs and hF-MWCNTs in epoxy were also predicted according to HSPs. It was found that hF-MWCNTs maintain a stable dispersion in epoxy due to their heterogeneous structure at elevated temperatures.

  12. Preparation of Ibuprofen-loaded Eudragit S100 nanoparticles by Solvent evaporation technique.

    Directory of Open Access Journals (Sweden)

    VINEELA CH

    2014-07-01

    Full Text Available Aim The aim of the present study is to prepare Ibuprofen loaded Eudragit-S100 nanoparticles by means of Solvent evaporation method. Span 80 is used as surfactant. The model drug, Ibuprofen is a non-steroidal antiinflammatory drug (NSAID commonly used for the relief of symptoms of arthritis, primary dysmenorrheal, alleviating fever and reducing inflammation. It also has an analgesic effect, anti-platelet effect and vasodilation effect. Ibuprofen is available in the form of extended release tablets, chewable tablets, sustained release capsules, liquid filled capsules, syrup and suspension. Methodology Solvent evaporation technique was adapted for the preparation of Ibuprofen loaded Eudragit S100 nanoparticles. Preformed polymeric and drug solution was used as internal phase and mineral oil with 1% span 80 is used as external phase and allowed for stirring resulting in the formation of nanoparticles. Parameters like stirring rate, polymer to drug concentration and organic solvent quantity were optimized. Results and Conclusion In order to optimize the concentration of drug, polymer and organic solvent, three formulations were prepared by varying the concentration of polymer and solvents. The results obtained were compared. On comparision formulation 3(1:2 was showing particles in nanorange (345nm, higher stability (-26.9mV and better entrapment efficiency (96.47. Invitro drug release studies were performed for a period of 10hrs and 46.02% of the drug has been released from the formulation. Conclusion It was observed that as the polymer ratio increases the release rate is sustained and encapsulation efficiency also increased.

  13. Investigation of solvent effect and cyclodextrins on fluorescence properties of ochratoxin A

    Science.gov (United States)

    Hashemi, Javad; Alizadeh, Naader

    2009-07-01

    Fluorescence properties of ochratoxin A (OTA) solutions depend on the pH, solvent polarity and can be influenced by the presence of cyclodextrins (CDs). In this work, the effect of b-cyclodextrin (b-CD) and heptakis-2,6-dimethyl-o-b-cyclodextrin (ome-CD), on fluorescence properties of OTA in aqueous solutions has been investigated by means of steady-state fluorescence at different pHs (range 2-10). Binding constants of OTA/CDs inclusion complexes have been determined by applying by non-linear regression analysis. A 1:1 stoichiometry of OTA/CDs complexes has been observed at all tested pHs. The use of ome-CD generally resulted in the greatest fluorescence intensity. The effects of solvent and pH on the positions of λmax (excitation) and λmax (emission) of OTA was determined. Correlations between the excitation and emission wavelength of OTA (monoanion and dianionic forms) and the solvent parameters were analysed with Lippert-Mataga plots. Results show that the peak position is affected mainly by specific and non-specific types of interactions between the solvent and solute. The fluorescence quenching of OTA by chloroform (aprotic) and water (protic) were studied in methanol as solvent at room temperature. The quenching was found to be appreciable and a non-linear curve with downward curvature was obtained in the Stern-Volmer (SV) plot for the water in the concentration range studied. The quenching efficiency is related to hydrogen bond-donating capacity of the quencher molecule. It was inferred that non-linearity can be attributed to fractional accessibility of fluorophore to quencher. The quenching constant was calculated from the modified SV equation.

  14. Innovative eco-friendly bio- solvent for combating sea surface and sedimented oil pollution

    Science.gov (United States)

    Theodorou, Paraskevas

    2017-04-01

    The combating of oil spill at sea surface by chemical dispersants accelerates the evaporation and disperse the oil into the water column, where it is broken down by natural processes and/or is sedimented at the sea bottom, especially at near coastal shallow areas, ports and marinas. The usual methodology for cleaning the sedimented oil from the sea bottom is mainly carried out via excavation and dumping of the polluted sediment into deeper sea areas, where the contamination is transferred from one area to another. The eco-friendly bio-solvent MSL Aqua 250 is an innovative new solution based mainly on natural constituents. The action mechanism and the effectiveness of this eco-friendly solvent is based on the high surface tension process. Organic compounds, including hydrocarbons upon coming in contact with MSL Aqua 250 solvent generate a significant surface tension reaction, which is able to alter the organic compounds to liquid form and then to drastically evaporate it. The use of MSL Aqua 250 solvent, both at sea surface and at the bottom, has the following advantages compared to the dispersants: • Efficient solution without transferring the pollution from sea surface to the water column and to the bottom or disturbing the Aquatic Eco System. • Non-Toxic. • Environmentally friendly with a restoration of marine life in the Eco System. • Cost effective. The MSL Aqua 250 solvent has been tested in cooperation with the Cyprus Department of Fisheries and Marine Research and the Technological University of Cyprus and used during the years 2015 and 2016 in marinas and fishing shelters in Cyprus faced oil pollution, with high concentration in the sea water and at the sea bottom of chemical parameters (BOD5, COD, FOG, TKN, TP, TPH), with excellent results.

  15. Solvent extraction of chlorinated compounds from soils and hydrodechlorination of the extract phase.

    Science.gov (United States)

    Murena, Fabio; Gioia, Francesco

    2009-03-15

    The remediation of soils contaminated with chlorinated compounds was investigated. The process consists of solvent extraction followed by catalytic hydroprocessing (hydrodechlorination) of the extract phase. A mixture of ethylacetate-acetone-water (E-A-W) was adopted as solvent in the extraction process. Tests of extraction of chlorobenzene from a model contaminated soil were carried out and the Langmuir adsorption equation was characterized. The solvent, contaminated with different chlorinated compounds was then hydrotreated with a Pd/C catalyst. The chlorinated compounds tested are: chlorobenzene, hexachlorobenzene and hexachloroethane at various initial concentrations. The reaction runs were carried out at room temperature and at a hydrogen pressure of 1bar. Hydrotreating of these compounds takes place according to a Langmuir-Hinshelwood mechanism whose kinetic parameters were determined. The experiments show that high destruction efficiencies may be reached in reasonably short times, particularly for hexachloroethane. Longer times are necessary for the aromatic compounds (chlorobenzene and hexachlorobenzene) for which the CCl bond is much stronger than that in the aliphatic compound. Time for a 95% destruction efficiency for all experimental runs was determined. A noteworthy finding is that ethylacetate and acetone do not undergo any reaction during hydrotreating. Thus the treated extract solution may be recycled inasmuch as it conserves its full extracting capacity towards chlorinated compounds. A limitation in recycling is the inhibiting effect of benzene on the HDCl rate: benzene produced by HDCl of chlorinated compounds, accumulates in the solvent mixture in the event of recycling. Simulation of the process with the recycling of the solvent was carried out, accounting for the inhibiting effect of benzene.

  16. Effects of temperature and solvent concentration on the solvent crystallization of palm-based dihydroxystearic acid with isopropyl alcohol

    Institute of Scientific and Technical Information of China (English)

    Gregory F.L.Koay; Teong-Guan Chuah; Sumaiya Zainal-Abidin; Salmiah Ahmad; Thomas S.Y.Choong

    2012-01-01

    Palm-based dihydroxystearic acid of 69.55% purity was produced in a 500-kg-per-batch operation pilot plant and purified through solvent crystallization in a custom fabricated simultaneous batch crystallizer unit.The effects of temperature and solvent concentration on yield,particle size distribution and purity were studied.The purity was higher,while the yield and particle size were lower and smaller,respectively,at higher temperature and solvent concentration.The solvent crystallization process efficiency was rated at 66-69% when carried out with 70-80% isopropyl alcohol at 20 ℃.

  17. STABILITY OF A CYLINDRICAL SOLUTE-SOLVENT INTERFACE: EFFECT OF GEOMETRY, ELECTROSTATICS, AND HYDRODYNAMICS*

    OpenAIRE

    Li, Bo; Sun, Hui; Zhou, Shenggao

    2015-01-01

    The solute-solvent interface that separates biological molecules from their surrounding aqueous solvent characterizes the conformation and dynamics of such molecules. In this work, we construct a solvent fluid dielectric boundary model for the solvation of charged molecules and apply it to study the stability of a model cylindrical solute-solvent interface. The motion of the solute-solvent interface is defined to be the same as that of solvent fluid at the interface. The solvent fluid is assu...

  18. Mechanism of transport and distribution of organic solvents in blood

    Science.gov (United States)

    Lam, C. W.; Galen, T. J.; Boyd, J. F.; Pierson, D. L.

    1990-01-01

    Little is known about the mechanism of transport and distribution of volatile organic compounds in blood. Studies were conducted on five typical organic solvents to investigate how these compounds are transported and distributed in blood. Groups of four to five rats were exposed for 2 hr to 500 ppm of n-hexane, toluene, chloroform, methyl isobutyl ketone (MIBK), or diethyl ether vapor; 94, 66, 90, 51, or 49%, respectively, of these solvents in the blood were found in the red blood cells (RBCs). Very similar results were obtained in vitro when aqueous solutions of these solvents were added to rat blood. In vitro studies were also conducted on human blood with these solvents; 66, 43, 65, 49, or 46%, respectively, of the added solvent was taken up by the RBCs. These results indicate that RBCs from humans and rats exhibited substantial differences in affinity for the three more hydrophobic solvents studied. When solutions of these solvents were added to human plasma and RBC samples, large fractions (51-96%) of the solvents were recovered from ammonium sulfate-precipitated plasma proteins and hemoglobin. Smaller fractions were recovered from plasma water and red cell water. Less than 10% of each of the added solvents in RBC samples was found in the red cell membrane ghosts. These results indicate that RBCs play an important role in the uptake and transport of these solvents. Proteins, chiefly hemoglobin, are the major carriers of these compounds in blood. It can be inferred from the results of the present study that volatile lipophilic organic solvents are probably taken up by the hydrophobic sites of blood proteins.

  19. Solvent and Substituent Effects on the Thermolysis of Antimalarial Fluorophenyl Substituted 1,2.4-Trioxanes

    Directory of Open Access Journals (Sweden)

    Ruben S. Rimada

    2003-08-01

    Full Text Available The kinetics and mechanism of the thermal decomposition reaction of cis-6-(4-fluoropheny1-5,6-[2-(4-fluorophenyl-propylidene]-3,3-tetramethylene-l,2,4-trioxacyclohexane (I were investigated separately in n-hexane and in methanol solutions over the temperature and concentration ranges of 393.2-443.2 K and 2.7-54 x l0-5 M, respectively. The values of the activation parameters for both reactions were compared with the corresponding ones for the thermolysis of cis-6-(4-fluorophenyl-5,6-[2-(4-fluorophenyl-3-hydroxypropylidene]-3,3-tetramethylene-1,2,4-trioxacyclohexane (II, investigated in the same solvents and temperature range. Substituent and solvent effects on the initial homolytic rupture of the O-O peroxydic bonds of those molecules were evaluated.

  20. Effect of Pressure on Absorption Spectra of Lycopene in n-Hexane and CS2 Solvents

    Science.gov (United States)

    Zhang, Wei; Liu, Wei-Long; Zheng, Zhi-Ren; Huo, Ming-Ming; Li, Ai-Hua; Yang, Bin

    2010-01-01

    The absorption spectra of lycopene in n-hexane and CS2 are measured under high pressure and the results are compared with β-carotene. In the lower pressure range, the deviation from the linear dependence on the Bayliss parameter (BP) for β-carotene is more visible than that for lycopene. With the further increase of the solvent BP, the 0-0 bands of lycopene and β-carotene red shift at almost the same rate in n-hexane; however, the 0-0 band of lycopene red shifts slower than that of β-carotene in CS2. The origins of these diversities are discussed taking into account the dispersion interactions and structures of solute and solvent molecules.

  1. Influence of solvents on properties of solar selective coatings obtained by spray pyrolysis

    Indian Academy of Sciences (India)

    Mihaela Dudita; Luminita Isac; Anca Duta

    2012-11-01

    Solar selective coatings for solar thermal flat-plate collectors consisting of crystalline copper oxides and amorphous nickel oxide composites were obtained by robotic spray pyrolyzed deposition. The parameters were optimized for increased spectral selectivity (): high solar absorptance and low thermal emittance. The coatings were deposited using nickel and copper acetate, dissolved in mixed solvents with various water: ethanol ratios. The coatings’ properties were characterized in terms of crystalline composition (XRD), surface morphology (AFM, contact angle) and optical properties (solar absorptance, thermal emittance and spectral selectivity). Considering the precursor solutions composition (solvent, wetting behaviour), the growth processes were modelled for two different systems: predominant hydrophilic and predominant hydrophobic. The high selectivity values ( > 30) of the optimized composite coatings were explained based on two parallel mechanisms: intrinsic absorption and multiple reflections generated when absorbers with controlled roughness are deposited.

  2. Spectral characteristics of tramadol in different solvents and β-cyclodextrin

    Science.gov (United States)

    Anton Smith, A.; Manavalan, R.; Kannan, K.; Rajendiran, N.

    2009-10-01

    Effect of solvents and β-cyclodextrin on the absorption and fluorescence spectra of tramadol drug has been investigated and compared with anisole. The solid inclusion complex of tramadol with β-CD is investigated by FT-IR, 1H NMR, scanning electron microscope (SEM), DSC and semiempirical methods. The thermodynamic parameter (Δ G) of inclusion process is determined. A solvent study shows (i) the spectral behaviour of both tramadol and anisole molecules is similar to each other and (ii) the cyclohexanol group in tramadol is not effectively conjugated with anisole group. However, in β-CD, due to space restriction of the CD cavity, a weak interaction is present between the above groups in tramadol. β-Cyclodextrin studies show that tramadol forms 1:2 inclusion complex with β-CD. A mechanism is proposed for the inclusion process.

  3. Electron Donor-Acceptor Interaction of 8-Hydroxyquinoline with Citric Acid in Different Solvents: Spectroscopic Studies

    Directory of Open Access Journals (Sweden)

    Demelash Jado

    2014-01-01

    Full Text Available Charge transfer complex formation between 8-hydroxyquinoline as the electron donor and citric acid as the electron acceptor has been studied spectrophotometrically in ethanol and methanol solvents at room temperature. Absorption band due to charge transfer complex formation was observed near 320 and 325 nm in ethanol and methanol, respectively. The stoichiometric ratio of the complex has been found 3 : 1 by using Job’s and conductometric titration methods. Benesi-Hildebrand equation has been applied to estimate the formation constant and molecular extinction coefficient. It was found that the value of formation constant was larger in ethanol than in methanol. The physical parameters, ionization potential, and standard free energy change of the formed complex were determined and evaluated in the ethanol and methanol solvents.

  4. A parametric simulation study for solvent co-injection process in bitumen deposits

    Energy Technology Data Exchange (ETDEWEB)

    Yazdani, A.; Alvestad, J.; Kjonsvik, D.; Gilje, E.; Kowalewski, E. [Statoil Canada (Canada)

    2011-07-01

    The extraction of very large Canadian extra heavy oil and bitumen deposits is facing major challenges, such as energy requirements and access to sustainable water resources. Steam assisted gravity drainage (SAGD) is the most common commercial in-situ recovery process used for the extraction but it has many associated economic and environmental challenges. Moreover, current knowledge of the fundamental physics and mechanics involved in the process is not satisfactory. This paper presents a parametric simulation study for a solvent co-injection (SCI) process in bitumen deposits. This process has the potential to improve the efficiency of steam processes as well as to reduce energy use and CO2 emissions. The study contributes to further understanding of the development process. Several operational and geological parameters were evaluated to assess their impact on SAGD operations. The results demonstrated that the basis for selecting the optimum solvent should not only be mobility improvement capability but should also include other operational and geological conditions.

  5. [Identification of organic solvents in the water of a freshly coated drinking-water reservoir].

    Science.gov (United States)

    Karrenbrock, F; Haberer, K

    1982-01-01

    Chloro-caoutschouc coatings on reservoirs made of concrete can release organic solvents to the drinking water for several month after applying. These solvents can be identified directly in the water by highly sensitive analytical methods (GC/MS). The concentrations verified distinctly exceed the maximum permissible concentration of 10 micrograms/l as suggested by the EEG for the parameter: "dissolved or emulsified hydrocarbons (after extraction by petroleum ether); mineral oils" (2). Protective chloro-caoutchouc coatings should therefore be tested for the release of organic substances to water according to the KTW-Recommendations of the German Federal Health Bureau (1). In future drinking water reservoirs should not be coated unless compelling reasons exist, such as to protect concrete against aggressive water.

  6. Structural rearrangements in a lamellar diblock copolymer thin film during treatment with saturated solvent vapor

    Science.gov (United States)

    Di, Zhenyu; Posselt, Dorthe; Smilgies, Detlef-M.; Papadakis, Christine M.

    2010-01-01

    We have investigated the structural changes in thin films of lamellar poly(styrene-b-butadiene) diblock copolymers during treatment with saturated cyclohexane vapor, a solvent slightly selective for polybutadiene. Using real-time, in-situ grazing-incidence small-angle X-ray scattering (GISAXS), the swelling and the rearrangement of the lamellae were investigated with a time resolution of a few seconds, and the underlying processes on the molecular level were identified. After a few minutes in vapor, a transient state with a more well-defined and more long-range ordered lamellar orientation was encountered. Additional parallel lamellae formed which we attribute to the increased degree of coiling of the polymers in the swollen state. Eventually, the film became disordered. These changes are attributed to the increased mobility of the swollen polymers and the gradually decreasing segment-segment interaction parameter in the film as solvent is absorbed. PMID:20305742

  7. GPU/CPU Algorithm for Generalized Born/Solvent-Accessible Surface Area Implicit Solvent Calculations.

    Science.gov (United States)

    Tanner, David E; Phillips, James C; Schulten, Klaus

    2012-07-10

    Molecular dynamics methodologies comprise a vital research tool for structural biology. Molecular dynamics has benefited from technological advances in computing, such as multi-core CPUs and graphics processing units (GPUs), but harnessing the full power of hybrid GPU/CPU computers remains difficult. The generalized Born/solvent-accessible surface area implicit solvent model (GB/SA) stands to benefit from hybrid GPU/CPU computers, employing the GPU for the GB calculation and the CPU for the SA calculation. Here, we explore the computational challenges facing GB/SA calculations on hybrid GPU/CPU computers and demonstrate how NAMD, a parallel molecular dynamics program, is able to efficiently utilize GPUs and CPUs simultaneously for fast GB/SA simulations. The hybrid computation principles demonstrated here are generally applicable to parallel applications employing hybrid GPU/CPU calculations.

  8. A newly isolated organic solvent tolerant Staphylococcus saprophyticus M36 produced organic solvent-stable lipase.

    Science.gov (United States)

    Fang, Yaowei; Lu, Zhaoxin; Lv, Fengxia; Bie, Xiaomei; Liu, Shu; Ding, Zhongyang; Xu, Weifeng

    2006-12-01

    Thirty-eight high lipase activity strains were isolated from soil, seawater, and Brassica napus. Among them, a novel organic solvent tolerant bacterium (strain M36) was isolated from the seawater in Jiangsu, China. Isolate M36 was able to grow at high concentration of benzene or toluene up to 40% (vol/vol), and later identified as Staphylococcus saprophyticus by biochemical test and 16s ribosomal DNA sequence. No work on Staphylococcus producing lipase with organic solvent tolerance has been reported so far. The lipase of strain M36 whose activity in liquid medium was 42 U mL(-1) at 24-h incubation time was stable in the presence of 25% (vol/vol) p-xylene, benzene, toluene, and hexane.

  9. Influence of solvent on the morphology and microstructure of YSZ films obtained by spray pyrolysis technique; Influencia do solvente na morfologia e microestrutura de filmes de YSZ obtidos pela tecnica spray pirolise

    Energy Technology Data Exchange (ETDEWEB)

    Falcade, T.; Oliveira, G.B.; Mueller, I.L.; Malfatti, C.F., E-mail: tiagocoti@gmail.co, E-mail: celia.malfatti@ufrgs.b [Universidade Federal do Rio Grande do Sul (LAPEC/PPGEM/UFRGS), Porto Alegre, RS (Brazil). Programa de Pos-graduacao em Engenharia de Minas. Lab. de Pesquisa em Corrosao; Tarrago, D.P.; Sousa, V.C.; Bergmann, C.P. [Universidade Federal do Rio Grande do Sul (PPGEM/UFRGS), Porto Alegre, RS (Brazil). Programa de Pos-graduacao em Engenharia de Minas; Souza, M.M.V.M. [Universidade Federal do Rio de Janeiro (UFRJ), RJ (Brazil)

    2010-07-01

    This work aims to investigate the influence of solvent used for the deposition of thin films of yttria stabilized zirconia (YSZ) on porous substrate. The films were obtained directly on the porous LSM substrate by spray pyrolysis technique, which consists of spraying a precursor solution containing salts of zirconium (Zr (C{sub 6}H{sub 7}O{sub 2}) 4) and yttrium (YCl{sub 3}.6H{sub 2}O), dissolved in specific solvents, on the heated substrate. The use of solvents with different boiling points and viscosity aims the optimization of experimental operating parameters to obtain homogeneous and dense films suitable for application as electrolyte in fuel cells, solid oxide (SOFC). The films were characterized by scanning electron microscopy, infrared spectroscopy and X-ray diffraction. (author)

  10. Solvent Effects upon Electrochemical Kinetics: Influences of Interfacial Solvation and Solvent Relaxation Dynamics.

    Science.gov (United States)

    1984-09-01

    by block number) incganic and organometallic complexes ; inner-shell barrier; electrochemical kinetics Z-. ASS-ACT (Continue on reverse aid* If...valuable class of model systems is provided by one- electron couples involving substitutionally inert inorganic and organometallic complexes . Important...specific ligand- solventOs interactions, perhaps with accompanying decreases in Kel (6). This explanation is consisterwith the observation that ksb decreases

  11. Ultrasound induced green solvent extraction of oil from oleaginous seeds.

    Science.gov (United States)

    Sicaire, Anne-Gaëlle; Vian, Maryline Abert; Fine, Frédéric; Carré, Patrick; Tostain, Sylvain; Chemat, Farid

    2016-07-01

    Ultrasound-assisted extraction of rapeseed oil was investigated and compared with conventional extraction for energy efficiency, throughput time, extraction yield, cleanness, processing cost and product quality. A multivariate study enabled us to define optimal parameters (7.7 W/cm(2) for ultrasonic power intensity, 40 °C for processing temperature, and a solid/liquid ratio of 1/15) for ultrasound-assisted extraction of oil from oilseeds to maximize lipid yield while reducing solvent consumption and extraction time using response surface methodology (RSM) with a three-variable central composite design (CCD). A significant difference in oil quality was noted under the conditions of the initial ultrasound extraction, which was later avoided using ultrasound in the absence of oxygen. Three concepts of multistage cross-current extraction were investigated and compared: conventional multistage maceration, ultrasound-assisted maceration and a combination, to assess the positive impact of using ultrasound on the seed oil extraction process. The study concludes that ultrasound-assisted extraction of oil is likely to reduce both economic and ecological impacts of the process in the fat and oil industry.

  12. Solvent fluctuations around solvophobic, solvophilic, and patchy nanostructures and the accompanying solvent mediated interactions

    Science.gov (United States)

    Chacko, Blesson; Evans, Robert; Archer, Andrew J.

    2017-03-01

    Using classical density functional theory (DFT), we calculate the density profile ρ (𝐫 ) and local compressibility χ (𝐫 ) of a simple liquid solvent in which a pair of blocks with (microscopic) rectangular cross section are immersed. We consider blocks that are solvophobic, solvophilic and also ones that have both solvophobic and solvophilic patches. Large values of χ (𝐫 ) correspond to regions in space where the liquid density is fluctuating most strongly. We seek to elucidate how enhanced density fluctuations correlate with the solvent mediated force between the blocks, as the distance between the blocks and the chemical potential of the liquid reservoir vary. For sufficiently solvophobic blocks, at small block separations and small deviations from bulk gas-liquid coexistence, we observe a strongly attractive (near constant) force, stemming from capillary evaporation to form a low density gas-like intrusion between the blocks. The accompanying χ (𝐫 ) exhibits a structure which reflects the incipient gas-liquid interfaces that develop. We argue that our model system provides a means to understanding the basic physics of solvent mediated interactions between nanostructures, and between objects such as proteins in water that possess hydrophobic and hydrophilic patches.

  13. Carboxymethylation of Cassava Starch in Different Solvents and Solvent-Water Mixtures: Optimization of Reaction Conditions

    Science.gov (United States)

    Nwokocha, Louis M.; Ogunmola, Gabiel B.

    The influence of reaction medium on carboxymethylation process was investigated by treating cassava starch with sodium monochloroacetate in different solvents and solvent-water mixtures under alkaline conditions. The amount of carboxyl groups introduced into the starch moiety was determined titrimetrically and used to calculate the Degree of Substitution (DS) and Reaction Efficiency (RE). The results showed that carboxymethylation is significantly affected by the nature of reaction medium at p<0.05. Carboxymethylation in different solvent-water mixtures showed that aqueous 80% n-propanol offered the best medium for carboxymethylation. Optimization of reaction conditions in aqueous 80% n-propanol showed that the best condition for carboxymethylation was at starch-liquor ratio of 1:3, NaOH/reagent molar ratio of 4.0 and reagent-starch molar ratio of 0.35. An increase in temperature was required to effect the reaction at shorter time. At 55°C the highest values of DS and RE achieved in 0.5 h would require three hours to achieve the same values of DS and RE at 45°C.

  14. Coprocessing of coal and heavy petroleum crudes and residua: a solvent evaluation and a parametric study

    Energy Technology Data Exchange (ETDEWEB)

    Curtis, C.W.; Guin, J.A.; Tsai, K.J.; Pass, M.C.

    1984-01-01

    This study has investigated the combined hydroprocessing of coal with petroleum solvents consisting of heavy and reduced crudes and residua to determine the feasibility of simultaneous upgrading of both materials to lighter products. Six hydrogen-rich heavy petroleum materials have been processed with Illinois No. 6 coal at 400/sup 0/C and 425/sup 0/C for 30 minutes under three reaction conditions: a N/sub 2/ atmosphere, a H/sub 2/ atmosphere and a H/sub 2/ atmosphere using hydrotreating extrudates. Liquefaction of bituminous coal can be achieved in the petroleum solvents with coal conversion being dependent upon the reaction conditions. Noncatalytic coal conversions of 45 to 50% are achieved in a H/sub 2/ atmosphere. Addition of a catalyst increases conversion to near 70%. Only approximately 35% conversion is obtained in a N/sub 2/ atmosphere. In the catalytic environment substantial conversions to pentane soluble material occur. Hydrotreatment and extraction of the solvent prior to coprocessing increases the amount of coal conversion and, in some cases, increases the amount of pentane soluble material produced. The influence of the solvent appears to be related to the molecular weight, viscosity and Conradson Carbon number of the petroleum materials. Evaluation of the reaction parameters of temperature, hydrogen pressure, time and catalyst extrudate size for coprocessing has been undertaken. Based on the production of pentane soluble oil and coal conversion, feasible parameters are established: 425/sup 0/C, 1250 psig H/sub 2/ pressure at ambient temperature, long reaction time and a hydrogenation catalyst with a small particle size. Combined processing is shown to be sensitive to catalyst extrudate size, with powdered catalyst giving substantially more oil yield and coal conversion than the extrudates. 6 references, 11 figures, 4 tables.

  15. Solvent dynamical behavior in an organogel phase as studied by NMR relaxation and diffusion experiments.

    Science.gov (United States)

    Yemloul, Mehdi; Steiner, Emilie; Robert, Anthony; Bouguet-Bonnet, Sabine; Allix, Florent; Jamart-Grégoire, Brigitte; Canet, Daniel

    2011-03-24

    An organogelation process depends on the gelator-solvent pair. This study deals with the solvent dynamics once the gelation process is completed. The first approach used is relaxometry, i.e., the measurement of toluene proton longitudinal relaxation time T(1) as a function of the proton NMR resonance frequency (here in the 5 kHz to 400 MHz range). Pure toluene exhibits an unexpected T(1) variation, which has been identified as paramagnetic relaxation resulting from an interaction of toluene with dissolved oxygen. In the gel phase, this contribution is retrieved with, in addition, a strong decay at low frequencies assigned to toluene molecules within the gel fibers. Comparison of dispersion curves of pure toluene and toluene in the gel phase leads to an estimate of the proportion of toluene embedded within the organogel (found around 40%). The second approach is based on carbon-13 T(1) and nuclear Overhauser effect measurements, the combination of these two parameters providing direct information about the reorientation of C-H bonds. It appears clearly that reorientation of toluene is the same in pure liquid and in the gel phase. The only noticeable changes in carbon-13 longitudinal relaxation times are due to the so-called chemical shift anisotropy (csa) mechanism and reflect slight modifications of the toluene electronic distribution in the gel phase. NMR diffusion measurements by the pulse gradient spin-echo (PGSE) method allow us to determine the diffusion coefficient of toluene inside the organogel. It is roughly two-thirds of the one in pure toluene, thus indicating that self-diffusion is the only dynamical parameter to be slightly affected when the solvent is inside the gel structure. The whole set of experimental observations leads to the conclusion that, once the gel is formed, the solvent becomes essentially passive, although an important fraction is located within the gel structure.

  16. Origin of Asymmetric Solvation Effects for Ions in Water and Organic Solvents Investigated Using Molecular Dynamics Simulations: The Swain Acity-Basity Scale Revisited.

    Science.gov (United States)

    Reif, Maria M; Hünenberger, Philippe H

    2016-08-25

    The asymmetric solvation of ions can be defined as the tendency of a solvent to preferentially solvate anions over cations or cations over anions, at identical ionic charge magnitudes and effective sizes. Taking water as a reference, these effects are quantified experimentally for many solvents by the relative acity (A) and basity (B) parameters of the Swain scale. The goal of the present study is to investigate the asymmetric solvation of ions using molecular dynamics simulations, and to connect the results to this empirical scale. To this purpose, the charging free energies of alkali and halide ions, and of their hypothetical oppositely charged counterparts, are calculated in a variety of solvents. In a first set of calculations, artificial solvent models are considered that present either a charge or a shape asymmetry at the molecular level. The solvation asymmetry, probed by the difference in charging free energy between the two oppositely charged ions, is found to encompass a term quadratic in the ion charge, related to the different solvation structures around the anion and cation, and a term linear in the ion charge, related to the solvation structure around the uncharged ion-sized cavity. For these simple solvent models, the two terms are systematically counteracting each other, and it is argued that only the quadratic term should be retained when comparing the results of simulations involving physical solvents to experimental data. In a second set of calculations, 16 physical solvents are considered. The theoretical estimates for the acity A are found to correlate very well with the Swain parameters, whereas the correlation for B is very poor. Based on this observation, the Swain scale is reformulated into a new scale involving an asymmetry parameter Σ, positive for acitic solvents and negative for basitic ones, and a polarity parameter Π. This revised scale has the same predictive power as the original scale, but it characterizes asymmetry in an

  17. The experimental design approach to eluotropic strength of 20 solvents in thin-layer chromatography on silica gel.

    Science.gov (United States)

    Komsta, Łukasz; Stępkowska, Barbara; Skibiński, Robert

    2017-02-03

    The eluotropic strength on thin-layer silica plates was investigated for 20 chromatographic grade solvents available in current market. 35 model compounds were used as test subjects in the investigation. The use of modern mixture screening design allowed to estimate each solvent as a separate elution coefficient with an acceptable error of estimation (0.0913 of RM value). Additional bootstrapping technique was used to check the distribution and uncertainty of eluotropic estimates, proving very similar confidence intervals to linear regression. Principal component analysis proved that the only one parameter (mean eluotropic strength) is satisfactory to describe the solvent property, as it explains almost 90% of variance of retention. The obtained eluotropic data can be good appendix to earlier published results and their values can be interpreted in context of RM differences. Copyright © 2017 Elsevier B.V. All rights reserved.

  18. Effect of solvent evaporation temperature on the structure of two-dimensional melamine networks on Au(111)

    Science.gov (United States)

    Okada, Arifumi; Nakata, Yohei; Minou, Kosuke; Yoshimura, Masamichi; Kadono, Kohei

    2016-12-01

    By scanning tunneling microscopy (STM), we investigated two-dimensional (2D) structures of melamine formed on Au(111) surfaces by solvent evaporation. By increasing the evaporation temperature, the well-known ordered honeycomb 2D molecular phase, in which all molecules are linked by hydrogen bonding, changes to four coexisting phases, i.e., a 2D network consisting of linear segments, 1D molecular rows, and hexagonal and distorted hexagonal structures. The first two phases are sometimes observed in ultrahigh vacuum (UHV) on metallic substrates other than Au. The last two phases have lattice parameters close to those of the well-known honeycomb structure. The structural change observed in this study is attributed to local temperature and concentration distributions of the solution and substrate surface during solvent evaporation. From the results, we found that the molecular nanostructures can be tailored by the solvent evaporation method with small changes in temperature.

  19. Solvent pre-wetting as an effective start-up method for point-of-use filter

    Science.gov (United States)

    Umeda, Toru; Sugiyama, Shinichi; Nakamura, Takashi; Momota, Makoto; Sevegney, Michael; Tsuzuki, Shuichi; Numaguchi, Toru

    2012-03-01

    An effective filter start-up method has been required by device manufacturers, mainly in order to reduce waste volume of lithography process chemicals, which become more expensive as lithography technology advances. Remaining air was monitored during static-pressure-driven filter start-up. As a result, 3500 ml of the resist was needed to eliminate remaining air. For improvement, cyclohexanone pre-wetting was applied prior to the resist introduction. As a result, the resist volume needed for the solvent displacement was 1900 ml, approximately half the volume required for staticpressure- driven start-up. Other solvents were evaluated for the pre-wetting start-up method. Results, in descending order of performance were PGME (best) Hansen solubility parameter distance between each solvent and nylon 6,6 material.

  20. Solvent effect on the stability and properties of platinum-substituted borirene and boryl isomers: The polarizable continuum model

    Science.gov (United States)

    Ghiasi, Reza; Peikari, Ali

    2016-11-01

    The structure and properties of platinum borirene complex trans-[Cl(PMe3)2Pt{μ-BN(SiMe3)2C=C}Ph] and its isomer the platinum boryl complex trans-[Cl(PMe3)2PtBN(SiMe3)2C≡CPh] were investigated theoretically. The solvent effect on the stability, structural parameters, frontier orbital energies, HOMO-LUMO gaps, and hardness of isomers was investigated using the polarizable continuum model (PCM). It was found that borirene isomer is the most stable isomer in the gas phase and solvent. The calculated results show that the presence of solvent reduces the frontier orbital energy of the studied molecules. Geometries obtained from calculations were used to perform NBO analysis.