WorldWideScience

Sample records for 1,4-dioxane

  1. Butallylonal 1,4-dioxane hemisolvate

    Ulrich J. Griesser

    2010-10-01

    Full Text Available The asymmetric unit of the title compound [systematic name: 5-(1-bromoprop-2-en-1-yl-5-sec-butylpyrimidine-2,4,6-trione 1,4-dioxane hemisolvate], C11H15BrN2O3·0.5C4H8O2, contains one half-molecule of 1,4-dioxane and one molecule of butallylonal, with an almost planar barbiturate ring [largest deviation from the mean plane = 0.049 (5 Å]. The centrosymmetric dioxane molecule adopts a nearly ideal chair conformation. The barbiturate molecules are linked together by an N—H...O hydrogen bond, giving a single-stranded chain. Additionally, each dioxane molecule acts as a bridge between two antiparallel strands of hydrogen-bonded barbiturate molecules via two hydrogen bonds, N—H...O(dioxaneO...H—N. Thus, a ladder structure is obtained, with the connected barbiturate molecules forming the `stiles' and the bridging dioxane molecules the `rungs'.

  2. Cytenamide–1,4-dioxane (2/1

    Colin T. Bedford

    2008-07-01

    Full Text Available In the crystal structure of the title compound [systematic name: 5H-dibenzo[a,d]cycloheptatriene-5-carboxamide–1,4-dioxane (2/1], 2C16H13NO·C4H8O2, the cytenamide molecules form a hydrogen-bonded R22(8 dimer. The solvent molecule is located between two adjacent cytenamide dimers and forms N—H...O hydrogen bonds with one cytenamide molecule from each dimer.

  3. Urea derivatives on the basis of 6-amino benzo-1.4-dioxan

    Present work is devoted to urea derivatives on the basis of 6-amino benzo-1.4-dioxan. The results of studies of condensation of 6-amino benzo-1.4-dioxan with urea and its derivatives are given. The new urea derivatives synthesized by fragment of 1.4-dioxan. (author)

  4. Degradation of 1,4-Dioxane and Cyclic Ethers by an Isolated Fungus

    Nakamiya, Kunichika; Hashimoto, Syunji; Ito, Hiroyasu; Edmonds, John S.; Morita, Masatoshi

    2005-01-01

    By using 1,4-dioxane as the sole source of carbon, a 1,4-dioxane-degrading microorganism was isolated from soil. The fungus, termed strain A, was able to utilize 1,4-dioxane and many kinds of cyclic ethers as the sole source of carbon and was identified as Cordyceps sinensis from its 18S rRNA gene sequence. Ethylene glycol was identified as a degradation product of 1,4-dioxane by the use of deuterated 1,4-dioxane-d8 and gas chromatography-mass spectrometry analysis. A degradation pathway invo...

  5. 5,5-Dihydroxybarbituric acid 1,4-dioxane hemisolvate

    Thomas Gelbrich

    2010-05-01

    Full Text Available The asymmetric unit of the title compound,, C4H4N2O5·0.5C4H8O2, contains one molecule of 5,5-dihydroxybarbituric acid with a nearly planar barbiturate ring and half a molecule of 1,4-dioxane. The geometry of the centrosymmetric dioxane molecule is close to an ideal chair conformation. The crystal structure exhibits a complex three-dimensional hydrogen-bonded network. Barbiturate molecules are connected to one another via N—H...O=C, O—H...O=C and N—H...O(hydroxy interactions, while the barbituric acid molecule is linked to dioxane by an O—H...O contact.

  6. The fragmentation pattern of 1,4-dioxane ion

    Dunbar, Robert C.; Huang, Fu-Shiuan; Klippenstein, Stephen J.

    1993-09-01

    Fragmentation of 1,4-dioxane ions at low internal energies was studied by photodissociation in the ion cyclotron resonance (ICR) ion trap. Branching ratios, rate--energy curves and kinetic parameters were assigned for the m/z 58, 57 and 45 fragment ions. M/z 58 is formed through a slightly tight rate-limiting transition state (E0 = 1.46 eV, [Delta]S+1000K = -1.4 e.u.) which probably corresponds to rupture of the dioxane ring. M/z 45 is formed through a tight transition state (E0 = 1.42 eV, [Delta]S++1000K = -10.9 eV) which presumably reflects a cyclic rearrangement pathway. The kinetic data for formation of 57 are almost equally well fitted by assuming competitive (RRKM) fragmentation from the parent ion, or assuming sequential fragmentation through an intermediate 58 ion. If the mechanism is solely competitive, the transition state is extraordinary loose (E0 = 1.87 eV, [Delta]S++1000K = 14.8 e.u.) which would be very surprising for this rearrangement dissociation. Accordingly we lean toward a sequential dissociation mechanism leading to the 57 product, and suggest further experimental testing of this possibility via structural studies of the 57 fragment.

  7. Implications of matrix diffusion on 1,4-dioxane persistence at contaminated groundwater sites.

    Adamson, David T; de Blanc, Phillip C; Farhat, Shahla K; Newell, Charles J

    2016-08-15

    Management of groundwater sites impacted by 1,4-dioxane can be challenging due to its migration potential and perceived recalcitrance. This study examined the extent to which 1,4-dioxane's persistence was subject to diffusion of mass into and out of lower-permeability zones relative to co-released chlorinated solvents. Two different release scenarios were evaluated within a two-layer aquifer system using an analytical modeling approach. The first scenario simulated a 1,4-dioxane and 1,1,1-TCA source zone where spent solvent was released. The period when 1,4-dioxane was actively loading the low-permeability layer within the source zone was estimated to be solvent source zones, suggesting that back diffusion of 1,4-dioxane mass may be serving as the dominant long-term "secondary source" at many contaminated sites that must be managed using alternative approaches. PMID:27096631

  8. Biodegradation Kinetics of 1,4-Dioxane in Chlorinated Solvent Mixtures.

    Zhang, Shu; Gedalanga, Phillip B; Mahendra, Shaily

    2016-09-01

    This study investigated the impacts of individual chlorinated solvents and their mixtures on aerobic 1,4-dioxane biodegradation by Pseudonocardia dioxanivorans CB1190. The established association of these co-occurring compounds suggests important considerations for their respective biodegradation processes. Our kinetics and mechanistic studies demonstrated that individual solvents inhibited biodegradation of 1,4-dioxane in the following order: 1,1-dichloroethene (1,1-DCE) > cis-1,2-diochloroethene (cDCE) > trichloroethene (TCE) > 1,1,1-trichloroethane (TCA). The presence of 5 mg L(-1) 1,1-DCE completely inhibited 1,4-dioxane biodegradation. Subsequently, we determined that 1,1-DCE was the strongest inhibitor of 1,4-dioxane biodegradation by bacterial pure cultures exposed to chlorinated solvent mixtures as well as in environmental samples collected from a site contaminated with chlorinated solvents and 1,4-dioxane. Inhibition of 1,4-dioxane biodegradation rates by chlorinated solvents was attributed to delayed ATP production and down-regulation of both 1,4-dioxane monooxygenase (dxmB) and aldehyde dehydrogenase (aldH) genes. Moreover, increasing concentrations of 1,1-DCE and cis-1,2-DCE to 50 mg L(-1) respectively increased 5.0-fold and 3.5-fold the expression of the uspA gene encoding a universal stress protein. In situ natural attenuation or enhanced biodegradation of 1,4-dioxane is being considered for contaminated groundwater and industrial wastewater, so these results will have implications for selecting 1,4-dioxane bioremediation strategies at sites where chlorinated solvents are present as co-contaminants. PMID:27486928

  9. Synthesis and antiinflammatory activity of 6-Acylsubstituted benzo-1,4-dioxanes and dihydrobenzopyrans

    Daukshas, V.K.; Brukshtus, A.B.; Gaidyalis, P.G.; Pyatrauskas, O.Yu.; Udrenaite, E.B.

    1986-07-01

    6-Acylsubstituted benzo-1,4-dioxanes and dihydrobenzopyrans were synthesized by the Friedel-Crafts reaction by the acylation of benzo-1,4-dioxane or corresponding dihydrobenzopyran with an acid chloride in the presence of anhydrous AlCl/sub 3/; the ketone was obtained by the hydrogenation of the chalcone using Raney nickel. The antiinflammatory activity was studied on experimental models of carragheen and bentonite edema of the foot of white rats. Results indicate that derivatives of benzo-1,4-dioxane and dihydrobenzopyran of the type studied show promise as antiinflammatory agents.

  10. Low level estimation of 1,4-dioxane in ambient air

    The chemical, 1,4-dioxane does have much relevance with respect to Indian Nuclear Power Programme for counting of Tritium, which is mainly generated during the operation of nuclear research reactors and power reactors which use heavy water. Tritium analysis is routinely carried out at BARC. The scintillation solutions which are used for tritium counting, consist of mainly 1,4 dioxane and naphthalene along with minor concentration of PPO/POPOP. Each sample analysis generates about 10 ml of tritium contaminated spent scintillation liquid waste. Total generation rate of the waste in a typical PHWR reactor is about 2-3 m3 /year. Controlled incineration of scintillation liquids has been opted at BARC for the treatment of radioactive organic waste. Now that 1,4-dioxane has shown threat to human health and environment, it is important and necessary to know its levels (concentrations) in different environmental compartments to evaluate the risks associated with it. Standard methods are available for the measurement of 1,4-dioxane in air. Higher concentration can be estimated by direct analysis but estimation at lower levels (parts per billion-ppb) requires pre concentration prior to its analysis. Here an improved method that offers increased sensitivity has been used for determining lower levels of 1,4-dioxane. This report presents (1) the development of the methodology for the estimation of 1,4-dioxane at ppb levels using cryogenic pre-concentration and subsequent analysis by Gas Chromatograph with Electron Capture detector (GC-ECD) (2) techniques to check the incineration efficiency and release of 1,4-dioxane to the environment. The data generated by this study could be further used in the evaluation of risk. (author)

  11. Enantioselective Synthesis of Homo-N-Nucleosides Containing a 1,4-Dioxane Sugar Analog

    Qiang Yu

    2008-12-01

    Full Text Available A dioxane homo-sugar analog, (2S,5S-and (2R,5S-5-[(4S-2,2-dimethyl-1,3-dioxolan-4-yl]-2-iodomethyl-1,4-dioxane was prepared from (2R,3R-dimethyl tartrate, and further elaborated into the corresponding homo-N-nucleoside analogs by its reactions with uracil and adenine, respectively.

  12. Hydrate phase equilibria of furan, acetone, 1,4-dioxane, TBAC and TBAF

    Highlights: • Experimental hydrate dissociation conditions are reported for CO2/methane + some water soluble/insoluble hydrate formers. • An isochoric pressure-search method was used to generate the experimental data. • The data are compared with the corresponding literature data in the presence of pure water. • The hydrate promotion effects of acetone, 1,4-dioxane, furan, TBAC and TBAF are discussed. -- Abstract: In this communication, we first report experimental hydrate dissociation pressures for the methane/carbon dioxide + furan/acetone/1,4-dioxane + water and the methane + tetra n-butyl ammonium chloride (TBAC) + water as well as the carbon dioxide + tetra n-butyl ammonium floride (TBAF) + water systems in the temperature ranges of (269.9 to 303.3) K. An isochoric pressure-search method was used to generate the experimental data. The hydrate dissociation data are compared with the corresponding literature data, if exists, and the literature data in the presence of pure water and acceptable agreement is observed. A discussion is made on hydrate promotion effects of acetone, 1,4-dioxane, furan, TBAC and TBAF

  13. 1,4-Dioxane enhances properties and biocompatibility of polyanionic collagen for tissue engineering applications.

    Forti, Fabio L; Bet, Marcos R; Goissis, Gilberto; Plepis, Ana M G

    2011-08-01

    Polyanionic collagen obtained from bovine pericardial tissue submitted to alkaline hydrolysis is an acellular matrix with strong potential in tissue engineering. However, increasing the carboxyl content reduces fibril formation and thermal stability compared to the native tissues. In the present work, we propose a chemical protocol based on the association of alkaline hydrolysis with 1,4-dioxane treatment to either attenuate or revert the drastic structural modifications promoted by alkaline treatments. For the characterization of the polyanionic membranes treated with 1,4-dioxane, we found that (1) scanning electron microscopy (SEM) shows a stronger reorientation and aggregation of collagen microfibrils; (2) histological evaluation reveals recovering of the alignment of collagen fibers and reassociation with elastic fibers; (3) differential scanning calorimetry (DSC) shows an increase in thermal stability; and (4) in biocompatibility assays there is a normal attachment, morphology and proliferation associated with high survival of the mouse fibroblast cell line NIH3T3 in reconstituted membranes, which behave as native membranes. Our conclusions reinforce the ability of 1,4-dioxane to enhance the properties of negatively charged polyanionic collagen associated with its potential use as biomaterials for grafting, cationic drug- or cell-delivery systems and for the coating of cardiovascular devices. PMID:21643966

  14. Anodic oxidation of 1,4-dioxane on boron-doped diamond electrodes for wastewater treatment

    A study of the anodic oxidation of 1,4-dioxane, a refractory water pollutant, by boron-doped diamond (BDD) electrodes was carried out under a range of major system variables: initial concentration, current density, temperature, pH, and electrolyte concentration. The 1,4-dioxane removal behavior was monitored by chemical oxygen demand (COD), and the results were compared with theoretical models for the electrochemical incineration of organic compounds. The removal efficiency of COD was shown to be greater than 95% in most cases, and no electrode fouling was observed during the reaction. Experimental degradation behavior agreed well with the theoretical models, implying that system variables can be predicted, even when the process is applied at pilot scale. Processes conducted at lower initial concentrations and higher temperatures yielded better energy consumption efficiency. Conditions of higher current density yielded faster degradation but need greater quantities of charge loading into the system. Therefore, a compromise between treatment time and energy consumption is required to achieve the desired efficiency. Meanwhile, pH and electrolyte concentrations did not affect reaction efficiency, suggesting that pH adjustment prior to wastewater treatment is not necessary. Thus, anodic oxidation of 1,4-dioxane by BDD electrodes promises to be both an economical and an efficient in wastewater treatment process.

  15. Peroxone activated persulfate treatment of 1,4-dioxane in the presence of chlorinated solvent co-contaminants.

    Eberle, Dylan; Ball, Raymond; Boving, Thomas B

    2016-02-01

    1,4-dioxane is often found as a co-contaminant with chlorinated volatile organic compounds (VOCs) at solvent release sites such as landfills, solvent recycling facilities, or fire training areas. Historically, soil and groundwater samples were not routinely analyzed for 1,4-dioxane and therefore the number of known 1,4-dioxane sites is still increasing. Due to its co-occurrence with chlorinated compounds, remediation strategies are needed that simultaneously treat both 1,4-dioxane as well as chlorinated VOC co-contaminants. In this proof of concept laboratory study, the fate of 1,4-dioxane was examined during the targeted destruction of aqueous phase VOC, using a peroxone activated persulfate (PAP) chemical oxidation method. Bench-scale experiments were carried out to evaluate the treatability of 1,4-dioxane as both a single-contaminant and in the presence of trichloroethene (TCE), and 1,1,1-trichloroethane (1,1,1-TCA). Possible dependencies on oxidant concentration and reaction kinetics were studied. The oxidative destruction of 1,4-dioxane, TCE and 1,1,1-TCA in single-contaminant batch systems followed pseudo-first-order reaction kinetics and even at the most dilute oxidant concentration lasted for at least 13 days. The rate of oxidation for each contaminant increased linearly with increasing persulfate concentration over the range of oxidant concentrations tested. The rate of oxidative destruction, from most easily degraded to least, was: TCE > 1,4-dioxane > 1,1,1-TCA. Oxidation rates were up to 87% slower in a mixture of these three compounds. Although additional tests are necessary, our data suggest that PAP oxidation of 1,4-dioxane might aid in the cleanup of VOC contaminated sites. PMID:26408980

  16. Electro–oxidation of industrial wastewater containing 1,4-dioxane in the presence of different salts

    Barndok, Helen; Hermosilla, Daphne; Cortijo, Luis; Torres, Esperanza; Blanco, Ángeles

    2014-01-01

    The treatment of 1,4-dioxane solution by electrochemical oxidation on boron-doped diamond was studied using a central composite design and the response surface methodology to investigate the use of SO42- and HCO3- as supporting electrolytes considering the applied electric current, initial COD value, and treatment time. Two industrial effluents containing bicarbonate alkalinity, one just carrying 1,4-dioxane (S1), and another one including 1,4-dioxane and 2-methyl-1,3-dioxolane (S2), were tre...

  17. Short-chain grafting of tetrahydrofuran and 1,4-dioxane cycles on vinylchloride-maleic anhydride copolymer

    2009-01-01

    Full Text Available Mass increase of vinylchloride-maleic anhydride (VC-MA copolymer samples aged in tetrahydrofuran (THF or in 1,4-dioxane results from chemical interaction of VC-MA macromolecules with 1,4-dioxane or THF. Microstructure of the products of such modification was proved by infrared spectroscopy (IR- and nuclear magnetic resonance spectroscopy (13C NMR and 1H NMR. Mechanism of modification has been proposed. The results of microstructure research of VC-MA samples aged in THF and in 1,4-dioxane coincide with already known data on the reactions of opening of these and other oxygen-containing cycles under mild conditions.

  18. Experimental and Theoretical Investigation of Valence Orbitals in 1,4-Dioxane by Electron momentum Spectroscopy

    YANG Tie-Cheng; NING Chuan-Gang; SU Guo-Lin; DENG Jing-Kang; ZHANG Shu-Feng; REN Xue-Guang; HUANG Yan-Ru

    2006-01-01

    @@ The binding energy spectrum of all valence orbitals and the momentum distributions of highest occupied molecular orbital (HOMO: 8ag), 7bu + 7ag, 4bu, 2bg + 4ag and 2au in 1, 4-dioxane are investigated by electron momentum spectroscopy (EMS) with 600 e V impact energy. The experimental results are consistent with theoretical calculations of C2h chair conformation using the Hartree-Fock method and density functional theory with 6-311++G**and A UG-CC-PVTZ basis sets.

  19. Elastic scattering of low-energy electrons by 1,4-dioxane

    Barbosa, Alessandra Souza; Bettega, Márcio H. F.

    2014-05-01

    We report calculated cross sections for elastic collisions of low-energy-electrons with 1,4-dioxane. Our calculations employed the Schwinger multichannel method with pseudopotentials and were carried out in the static-exchange and static-exchange plus polarization approximations for energies up to 30 eV. Our results show the presence of three shape resonances belonging to the Bu, Au, and Bg symmetries and located at 7.0 eV, 8.4 eV, and 9.8 eV, respectively. We also report the presence of a Ramsauer-Townsend minimum located at around 0.05 eV. We compare our calculated cross sections with experimental data and R-matrix and independent atom model along with the additivity rule corrected by using screening coefficients theoretical results for 1,4-dioxane obtained by Palihawadana et al. [J. Chem. Phys. 139, 014308 (2013)]. The agreement between the present and the R-matrix theoretical calculations of Palihawadana et al. is relatively good at energies below 10 eV. Our calculated differential cross sections agree well with the experimental data, showing only some discrepancies at higher energies.

  20. Improvement of Lithium Interface Stability with 1,4-dioxane Pretreatment

    2007-01-01

    1,4-dioxane (DOA) was originally used to pretreat the lithium metal electrode in order to improve its interface stability. Electrochemical impedance spectra (EIS) measurements reveal that with DOA pretreatment, lithium electrode has a low and stable interracial resistance during the storage in electrolyte for a long time. And it is also found that the pretreated lithium electrode has an improved inteffacial performance in repeated charge/discharge cycles. Furthermore, it is proved by SEM that the pretreated one has smooth morphology after long-time storage or repeated charge/discharge cycles. Consequentially, because of more stable interface characteristics of lithium electrode, the rechargeable lithium cell with DOA pretreated lithium anode has an obviously enhanced discharging performance and a better cycleability, compared with that of the cell using the untreated lithium anode.

  1. Synthesis of a Novel Benzoyl Adenosine Analog Containing a 1, 4-Dioxane Sugar Analog and the Synthesis of a Corresponding Uracil Adenine Dinucleotide

    Per Carlsen

    2011-05-01

    Full Text Available Adenosine analogs in which the sugar unit was replaced by a 1,4-dioxane sugar equivalent, were prepared by coupling the 1,4-dioxane sugar analog as its anomeric acetates, with N6-benzoyl protected adenine. The 1,4-dioxane system was obtained in an enantioselective synthesis from (R,R-dimethyl tartrate. Using standard phosphorimidite methodology, the adenine analog was further reacted with a 1,4-dioxane uridine analog to give the corresponding, protected dinucleotide, set-up for further condensation into larger oligonucleotides.

  2. Advanced Electrochemical Oxidation of 1,4-Dioxane via Dark Catalysis by Novel Titanium Dioxide (TiO2) Pellets.

    Jasmann, Jeramy R; Borch, Thomas; Sale, Tom C; Blotevogel, Jens

    2016-08-16

    1,4-dioxane is an emerging groundwater contaminant with significant regulatory implications. Because it is resistant to traditional groundwater treatments, remediation of 1,4-dioxane is often limited to costly ex situ UV-based advanced oxidation. By varying applied voltage, electrical conductivity, seepage velocity, and influent contaminant concentration in flow-through reactors, we show that electrochemical oxidation is a viable technology for in situ and ex situ treatment of 1,4-dioxane under a wide range of environmental conditions. Using novel titanium dioxide (TiO2) pellets, we demonstrate for the first time that this prominent catalyst can be activated in the dark even when electrically insulated from the electrodes. TiO2-catalyzed reactors achieved efficiencies of greater than 97% degradation of 1,4-dioxane, up to 4.6 times higher than noncatalyzed electrolytic reactors. However, the greatest catalytic enhancement (70% degradation versus no degradation without catalysis) was observed in low-ionic-strength water, where conventional electrochemical approaches notoriously fail. The TiO2 pellet's dark-catalytic oxidation activity was confirmed on the pharmaceutical lamotrigine and the industrial solvent chlorobenzene, signifying that electrocatalytic treatment has tremendous potential as a transformative remediation technology for persistent organic pollutants in groundwater and other aqueous environments. PMID:27420906

  3. Kinetics and energy efficiency for the degradation of 1,4-dioxane by electro-peroxone process

    Highlights: • E-peroxone couples electrolysis with ozonation to driven peroxone reaction for pollutant degradation. • Significant amounts of ·OH can be efficiently produced in the E-peroxone process. • E-peroxone greatly enhances 1,4-dioxane degradation kinetics compared with ozonation and electrolysis. • E-peroxone consumes less energy for 1,4-dioxane mineralization than ozonation and electrolysis. • E-peroxone offers a cost-effective and energy-efficient alternative to degrade 1,4-dioxane. - Abstract: Degradation of 1,4-dioxane by ozonation, electrolysis, and their combined electro-peroxone (E-peroxone) process was investigated. The E-peroxone process used a carbon-polytetrafluorethylene cathode to electrocatalytically convert O2 in the sparged ozone generator effluent (O2 and O3 gas mixture) to H2O2. The electro-generated H2O2 then react with sparged O3 to yield aqueous ·OH, which can in turn oxidize pollutants rapidly in the bulk solution. Using p-chlorobenzoic acid as ·OH probe, the pseudo-steady concentration of ·OH was determined to be ∼0.744 × 10−9 mM in the E-peroxone process, which is approximately 10 and 186 times of that in ozonation and electrolysis using a Pt anode. Thanks to its higher ·OH concentration, the E-peroxone process eliminated 96.6% total organic carbon (TOC) from a 1,4-dioxane solution after 2 h treatment with a specific energy consumption (SEC) of 0.376 kWh g−1 TOCremoved. In comparison, ozonation and electrolysis using a boron-doped diamond anode removed only ∼6.1% and 26.9% TOC with SEC of 2.43 and 0.558 kWh g−1 TOCremoved, respectively. The results indicate that the E-peroxone process can significantly improve the kinetics and energy efficiency for 1,4-dioxane mineralization as compared to the two individual processes. The E-peroxone process may thus offer a highly effective and energy-efficient alternative to treat 1,4-dioxane wastewater

  4. Kinetics and energy efficiency for the degradation of 1,4-dioxane by electro-peroxone process

    Wang, Huijiao; Bakheet, Belal; Yuan, Shi; Li, Xiang; Yu, Gang [School of Environment, Tsinghua University, Beijing 100084 (China); Murayama, Seiichi [Power and Industrial Systems R& D Center, Toshiba Corporation, Fuchu-shi, Tokyo (Japan); Wang, Yujue, E-mail: wangyujue@tsinghua.edu.cn [School of Environment, Tsinghua University, Beijing 100084 (China)

    2015-08-30

    Highlights: • E-peroxone couples electrolysis with ozonation to driven peroxone reaction for pollutant degradation. • Significant amounts of ·OH can be efficiently produced in the E-peroxone process. • E-peroxone greatly enhances 1,4-dioxane degradation kinetics compared with ozonation and electrolysis. • E-peroxone consumes less energy for 1,4-dioxane mineralization than ozonation and electrolysis. • E-peroxone offers a cost-effective and energy-efficient alternative to degrade 1,4-dioxane. - Abstract: Degradation of 1,4-dioxane by ozonation, electrolysis, and their combined electro-peroxone (E-peroxone) process was investigated. The E-peroxone process used a carbon-polytetrafluorethylene cathode to electrocatalytically convert O{sub 2} in the sparged ozone generator effluent (O{sub 2} and O{sub 3} gas mixture) to H{sub 2}O{sub 2}. The electro-generated H{sub 2}O{sub 2} then react with sparged O{sub 3} to yield aqueous ·OH, which can in turn oxidize pollutants rapidly in the bulk solution. Using p-chlorobenzoic acid as ·OH probe, the pseudo-steady concentration of ·OH was determined to be ∼0.744 × 10{sup −9} mM in the E-peroxone process, which is approximately 10 and 186 times of that in ozonation and electrolysis using a Pt anode. Thanks to its higher ·OH concentration, the E-peroxone process eliminated 96.6% total organic carbon (TOC) from a 1,4-dioxane solution after 2 h treatment with a specific energy consumption (SEC) of 0.376 kWh g{sup −1} TOC{sub removed}. In comparison, ozonation and electrolysis using a boron-doped diamond anode removed only ∼6.1% and 26.9% TOC with SEC of 2.43 and 0.558 kWh g{sup −1} TOC{sub removed}, respectively. The results indicate that the E-peroxone process can significantly improve the kinetics and energy efficiency for 1,4-dioxane mineralization as compared to the two individual processes. The E-peroxone process may thus offer a highly effective and energy-efficient alternative to treat 1,4-dioxane

  5. Dielectric Relaxation Studies of Alkylacrylates with Ortho-Substituted Benzoic acids in 1, 4 - Dioxane

    F. Liakath Ali Khan*,1

    2014-07-01

    Full Text Available Dielectric absorption studies of Hydrogen bonded complexes of alkyl acrylates with ortho substituted benzoic acid (2 - Fluro benzoic acid, 2 - Iodo benzoic acid, 2 - Chloro benzoic acid, 2 - Bromo benzoic acid, and 2 - Nitro benzoic acid were studied at microwave frequency 9.43GHz in dilute solution of 1,4 - Dioxane at room temperature. Different dielectric parameters like dielectric constant ( and dielectric loss ( at microwave frequency, and static dielectric constant (0 and dielectric constant ( at optical frequency were determined. The validity of the single frequency equation proposed by Higasi et.al., for multiple relaxation time (1 was found to be a function of the hydrogen bonding strength in benzoic acid, whereas the group rotation relaxation time (2 was a function of the steric interaction of proton donor. The relaxation time was maximum at 1:1 molar ratios of alky acrylates with ortho substituted benzoic acid.

  6. Near infrared cavity enhanced absorption spectra of atmospherically relevant ether-1, 4-Dioxane

    Chandran, Satheesh; Varma, Ravi

    2016-01-01

    1, 4-Dioxane (DX) is a commonly found ether in industrially polluted atmosphere. The near infrared absorption spectra of this compound has been recorded in the region 5900-8230 cm- 1 with a resolution of 0.08 cm- 1 using a novel Fourier transform incoherent broadband cavity-enhanced absorption spectrometer (FT-IBBCEAS). All recorded spectra were found to contain regions that are only weakly perturbed. The possible combinations of fundamental modes and their overtone bands corresponding to selected regions in the measured spectra are tabulated. Two interesting spectral regions were identified as 5900-6400 cm- 1 and 8100-8230 cm- 1. No significant spectral interference due to presence of water vapor was observed suggesting the suitability of these spectral signatures for spectroscopic in situ detection of DX. The technique employed here is much more sensitive than standard Fourier transform spectrometer measurements on account of long effective path length achieved. Hence significant enhancement of weaker absorption lines above the noise level was observed as demonstrated by comparison with an available measurement from database.

  7. Hyperconjugative and Electrostatic Interactions as Anomeric Triggers in Archetypical 1,4-Dioxane Derivatives.

    Ortega, Pilar Gema Rodríguez; Montejo, Manuel; López González, Juan Jesús

    2016-02-01

    The anomeric effect accounts for the greater thermodynamic stability of axially arranged six-membered heterocycles holding an electronegative substituent at the C1 position. Within a frame of no general consensus, two different theories are typically claimed to justify this effect mostly based on either hyperconjugative or electrostatic factors. Here we report a theoretical-experimental study of the role of both as anomeric triggers in two archetypical 1,4-dioxane derivatives, using a suitable combination of spectroscopic (IR and vibrational circular dichroism) and computational techniques for the analysis of the solvation environment effect in their anomeric choices. VCD and IR spectroscopies are used as conformer-discriminating tools: a detailed analysis of the evolution of the spectral profiles allows assessing the theoretically predicted changes in the experimental α/β ratios when changing the polar solvent, which are fully explained on the basis of an extensive NBO energy partition scheme that provides a detailed view of the role of hyperconjugative and electrostatic interactions as anomeric regulators. Our results suggest that the anomeric equilibrium cannot be described by a single stereoelectronic effect but by the combined contribution of hyperconjugation and electrostatic repulsions, so that the β-anomeric choice in polar solvents is markedly driven by the strong attenuation of electrostatic repulsive interactions that occurs in solution. PMID:26663638

  8. Pilot test of biological removal of 1,4-dioxane from a chemical factory wastewater by gel carrier entrapping Afipia sp. strain D1.

    Isaka, Kazuichi; Udagawa, Makiko; Sei, Kazunari; Ike, Michihiko

    2016-03-01

    A pilot-scale (120 L) bioreactor system using a gel carrier-entrapped pure bacterial strain, Afipia sp. strain D1, capable of degrading 1,4-dioxane as a sole carbon and energy source was constructed and applied to treat real industrial wastewater containing 1,4-dioxane from a chemical factory. Although the wastewater not only contained high concentrations of 1,4-dioxane but also considerable amounts of other organic compounds (73 mg-TOCL(-1) on average), the bioreactor could efficiently remove 1,4-dioxane without significant inhibitory effects. The reactor startup could be completed within approximately 1 month by increasing the 1,4-dioxane loading rate (0.09-0.47 kg-dioxanem(-3)d(-1)) in a stepwise manner. Effective 1,4-dioxane removal was stably maintained for 3 months with an influent 1,4-dioxane of 570-730 mg L(-1), giving an average effluent concentration and removal rate of 3.4 mg L(-1) and 0.46 kg-dioxanem(-3)d(-1), respectively. A 1,4-dioxane loading fluctuation between 0.14 and 0.72 kg-dioxanem(-3)d(-1) did not significantly affect its removal, and more than 99% removal efficiency was constantly maintained. The Monod model could well describe the relationship between the effluent 1,4-dioxane concentration and 1,4-dioxane removal rates of the bioreactors, showing that the half-saturation constant (Ks) was 28 mg L(-1). PMID:26561749

  9. 1,4-Dioxane biodegradation at low temperatures in Arctic groundwater samples.

    Li, Mengyan; Fiorenza, Stephanie; Chatham, James R; Mahendra, Shaily; Alvarez, Pedro J J

    2010-05-01

    1,4-Dioxane biodegradation was investigated in microcosms prepared with groundwater and soil from an impacted site in Alaska. In addition to natural attenuation conditions (i.e., no amendments), the following treatments were tested: (a) biostimulation by addition of 1-butanol (a readily available auxiliary substrate) and inorganic nutrients; and (b) bioaugmentation with Pseudonocardia dioxanivorans CB1190, a well-characterized dioxane-degrading bacterium, or with Pseudonocardia antarctica DVS 5a1, a bacterium isolated from Antarctica. Biostimulation enhanced the degradation of 50 mg L(-1) dioxane by indigenous microorganisms (about 0.01 mg dioxane d(-1) mg protein(-1)) at both 4 and 14 degrees C, with a simultaneous increase in biomass. A more pronounced enhancement was observed through bioaugmentation. Microcosms with 50 mg L(-1) initial dioxane (representing source-zone contamination) and augmented with CB1190 degraded dioxane fastest (0.16 +/- 0.04 mg dioxane d(-1) mg protein(-1)) at 14 degrees C, and the degradation rate decreased dramatically at 4 degrees C (0.021 +/- 0.007 mg dioxane d(-1) mg protein(-1)). In contrast, microcosms with DVS 5a1 degraded dioxane at similar rates at 4 degrees C and 14 degrees C (0.018 +/- 0.004 and 0.015 +/- 0.006 mg dioxane d(-1) mg protein(-1), respectively). DVS 5a1 outperformed CB1190 when the initial dioxane concentration was low (500 microg L(-1), which is representative of the leading edge of plumes). This indicates differences in competitive advantages of these two strains. Natural attenuation microcosms also showed significant degradation over 6 months when the initial dioxane concentration was 500 microg L(-1). This is the first study to report the potential for dioxane bioremediation and natural attenuation of contaminated groundwater in sensitive cold-weather ecosystems such as the Arctic. PMID:20199795

  10. Possible Protective Effect Of Quercetin Against 1,4-Dioxane And Gamma Radiation Induced Oxidative Stress In Male Albino Rats Key words: Quercetin, 1,4-Dioxane, Irradiated rats

    Quercetin, a bioflavonoid, is frequently found in consumed foods including apples, berries, onion, tea and vegetables. Quercetin has many beneficial effects on human health including cardiovascular protection, anti-cancer activity, cataract prevention, anti-viral activity and anti inflammatory effects. The present study is an attempt to evaluate the radio-protective properties of quercetin in gamma irradiated rat and the toxic effect of administration of 1,4-dioxane as well as the efficacy of quercetin as one of the most important antioxidant flavonoid in diet. At the 3rd and 10th days after the last dose of dioxane injection (one month) and radiation exposure (6 Gy, fractionated), the biochemical analysis in the serum showed significant elevation in lipid peroxide content (MDA), gamma glutamyl transferase (GGT), lactate dehydrogenase (LDH) and alpha fetoprotein (AFP) accompanied by significant depletion in glutathione (GSH). Also, the results showed significant increase in the level of DNA fragmentation in liver tissues of rats. Supplementation of quercetin to rats before and during exposure to gamma radiation and/or administration of 1,4-dioxane induced significant amelioration in the levels of all studied parameters. According to the results obtained, it could be concluded that quercetin might provide a protection against oxidative stress and metabolic disorders induced by gamma irradiation and 1,4-dioxane.

  11. (2,2′-Bipyridine-κ2N,N′dichloridopalladium(II 1,4-dioxane hemisolvate

    Ricardo Alfredo Gutiérrez Márquez

    2014-06-01

    Full Text Available The asymmetric unit of the title compound, [PdCl2(C10H8N2]·0.5C4H8O2, consists of one PdII complex molecule and a half-molecule of 1,4-dioxane, the complete molecule being generated by inversion symmetry. The PdII atom has an almost square-planar coordination formed by the 2,2′-bipyridine ligand and two chloride ligands. Two intramolecular C—H...Cl hydrogen bonds occur. In the crystal, the PdII complex and 1,4-dioxane molecules are connected by C—H...O hydrogen bonds, forming a layer parallel to (10-1. Within the layer, weak π–π interactions [centroid–centroid distance = 3.817 (4 Å] are observed between the pyridine rings.

  12. In vitro BALB/3T3 cell transformation assay of nonoxynol-9 and 1,4-dioxane

    Sheu, C.W.; Moreland, F.M.; Lee, J.K.; Dunkel, V.C.

    1988-01-01

    The spermicidal surfactant nonoxynol-9 (Igepal CO-630, GAF Corp.) and a potential impurity, 1,4-dioxane, were tested in the in vitro cell transformation assay using BALB/3T3 cells. Two treatment periods, 48 hr and 13 days, were used. Nonoxynol-9, tested at levels up to 10 /sup +/g/ml, did not induce transformation, whereas dioxane was very active in the induction type II foci in the cultured BALB/3T3 cells.

  13. Activation of cellulose by 1,4-dioxane for dissolution in N,N-dimethylacetamide/LiCl

    Raus, Vladimír; Šturcová, Adriana; Dybal, Jiří; Šlouf, Miroslav; Vacková, Taťana; Šálek, Petr; Kobera, Libor; Vlček, Petr

    2012-01-01

    Roč. 19, č. 6 (2012), s. 1893-1906. ISSN 0969-0239 R&D Projects: GA ČR GAP108/12/0703; GA ČR GA106/09/1348 Institutional research plan: CEZ:AV0Z40500505 Institutional support: RVO:61389013 Keywords : cellulose activation * cellulose dissolution * 1,4-dioxane Subject RIV: CD - Macromolecular Chemistry Impact factor: 3.476, year: 2012

  14. Metabolism and toxicokinetics of 1,4-dioxane in humans after inhalational exposure at rest and under physical stress.

    Göen, Thomas; von Helden, Franziska; Eckert, Elisabeth; Knecht, Udo; Drexler, Hans; Walter, Dirk

    2016-06-01

    The present study investigated the toxicokinetics of 1,4-dioxane in humans exposed at rest and during physical stress. Eighteen volunteers were divided into three groups of six individuals each, who were exposed separately in three experiments to 20 ppm (73 mg/m(3)) 1,4-dioxane for 8 h. The first group was exposed at rest (Experiment 1), whereas the other groups performed exercises on a bicycle ergometer for 10 min every hour, corresponding to a physical exercise of 50 W (Experiment 2) and 75 W (Experiment 3), respectively. Blood samples were collected after 4 and 8 h, and all urine samples were collected over 24 h. The samples were analysed for 1,4-dioxane and its metabolite 2-(2-hydroxyethoxy)acetic acid (HEAA). The amount of urinary-eliminated HEAA increased during exposure and showed its maximum 9.8 ± 1.9 h after the beginning of exposure. The levels of 1,4-dioxane in blood and urine, however, barely rose above the limit of detection. Depending on the physical stress of the volunteers, the maximum elimination rate of HEAA in urine was significantly increased with 23.2 ± 7.7, 30.4 ± 7.2 and 41.8 ± 23.8 mg/h for Experiments 1, 2 and 3, respectively. Likewise, the cumulative HEAA excretion over 24 h increased with increasing physical stress; 53 ± 15 % of the theoretical inhaled 1,4-dioxane dose was excreted as HEAA in urine during the first 24 h. The average maximum level of HEAA ranged between 378 and 451 mg/g creatinine and increased with the applied physical stress. The half-life of HEAA was found to be 3.4 ± 0.5 h. Twenty-four hours after the beginning of the exposure, 31-51 mg HEAA/g creatinine were still detected in urine, indicating only a low accumulation of the metabolite during a working week. The study results revealed an increasing effect of the applied physical stress on the total eliminated amounts of HEAA as well as on the maximum HEAA levels at the end of exposure. For the estimation of biomonitoring equivalents to

  15. Neutron Scattering of Residual Hydrogen in 1,4-Dioxane-D8 Liquid. Understanding Measurements with Molecular Dynamics Simulations

    de Almeida, Valmor F. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Liu, Hongjun [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Herwig, Kenneth W. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Kidder, Michelle [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

    2016-01-25

    That incoherent scattering from protiated molecular liquids adds a constant background to the measured scattering intensity is well known, but less appreciated is the fact that coherent scattering is also induced by the presence of hydrogen in a deuterated liquid. In fact, the scattering intensity can be very sensitive, in the small-q region, with respect to the amounts and distribution of residual H in the system. We used 1,4-dioxane liquid to demonstrate that the partial structure factors of the HD and DD atom pairs contribute significantly to inter-molecular scattering and that uncertainty in the extent of deuteration account for discrepancies between simulations and measurements. Both contributions to uncertainty have similar magnitudes: scattering interference of the hydrogen-deuterium pair, and complementary interference from the deuterium-deuterium pair by virtue of chemical inhomogeneity. This situation arises in practice since deuteration of liquids is often 99% or less. A combined experimental and extensive computational study of static thermal neutron scattering of 1,4-dioxane demonstrates the foregoing. We show, through simulations, that the reason for the differences is the content of protiated dioxane (vendors quote 1%). We estimate that up to 5% (at 298K and at 343K) protiated mole fraction may be involved in generating the scattering differences. Finally, we find that the particular distribution of hydrogen in the protiated molecules affects the results significantly; here we considered molecules to be either fully protiated or fully deuterated. This scenario best reconciles the computational and experimental results, and leads us to speculate that the deuteration synthesis process tends to leave a molecule either fully deuterated or fully protiated. Although we have used 1,4-dioxane as a model liquid, the effects described in this study extend to similar liquids and similar systematic experimental/computational studies can be performed to either

  16. Neutron Scattering of Residual Hydrogen in 1,4-Dioxane-D8 Liquid. Understanding Measurements with Molecular Dynamics Simulations

    That incoherent scattering from protiated molecular liquids adds a constant background to the measured scattering intensity is well known, but less appreciated is the fact that coherent scattering is also induced by the presence of hydrogen in a deuterated liquid. In fact, the scattering intensity can be very sensitive, in the small-q region, with respect to the amounts and distribution of residual H in the system. We used 1,4-dioxane liquid to demonstrate that the partial structure factors of the HD and DD atom pairs contribute significantly to inter-molecular scattering and that uncertainty in the extent of deuteration account for discrepancies between simulations and measurements. Both contributions to uncertainty have similar magnitudes: scattering interference of the hydrogen-deuterium pair, and complementary interference from the deuterium-deuterium pair by virtue of chemical inhomogeneity. This situation arises in practice since deuteration of liquids is often 99% or less. A combined experimental and extensive computational study of static thermal neutron scattering of 1,4-dioxane demonstrates the foregoing. We show, through simulations, that the reason for the differences is the content of protiated dioxane (vendors quote 1%). We estimate that up to 5% (at 298K and at 343K) protiated mole fraction may be involved in generating the scattering differences. Finally, we find that the particular distribution of hydrogen in the protiated molecules affects the results significantly; here we considered molecules to be either fully protiated or fully deuterated. This scenario best reconciles the computational and experimental results, and leads us to speculate that the deuteration synthesis process tends to leave a molecule either fully deuterated or fully protiated. Although we have used 1,4-dioxane as a model liquid, the effects described in this study extend to similar liquids and similar systematic experimental/computational studies can be performed to either

  17. Physico-chemical and excess thermodynamic properties of methanol & ethanol with 1, 4-dioxane at 308 K

    Bedare, G. R.; Bhandakkar, V. D.; Suryavanshi, B. M.

    2012-12-01

    The molecular interaction studies in the binary liquid mixtures of two aliphatic alcohols with 1, 4-dioxane has been carried out at 308 K using ultrasonic technique. Using measured values of ultrasonic velocity, density and viscosity, acoustical parameters such as adiabatic compressibility, free volume, free length and their excess values like VfE, ßaE, LfE are evaluated. From the properties of these excess parameters, the nature and the strength of interactions in these binary systems are discussed. It has been observed that, weak dispersive type intermolecular interactions are confirmed in the systems investigated. Dipole inducement is found to be more predominant in methanol system.

  18. PERFORMANCE ANALYSIS OF 1,4 DIOXANE-ETHANOL-DIESEL BLENDS ON DIESEL ENGINES WITH AND WITHOUT THERMAL BARRIER COATING

    Chockalingam Sundar Raj

    2010-01-01

    Full Text Available 1,4 dioxane, a new additive allows the splash blending of ethanol in diesel in a clear solution. The objective of this investigation is to first create a stable ethanol-diesel blended fuel with 10% 1,4 dioxane additive, and then to generate performance, combustion and emissions data for evaluation of different ethanol content on a single cylinder diesel engine with and without thermal barrier coating. Results show improved performance with blends compared to neat fuel for all conditions of the engine. Drastic reduction in smoke density is found with the blends as compared to neat diesel and the reduction is still better for coated engine. NOx emissions were found to be high for coated engines than the normal engine for the blends. The oxygen enriched fuel increases the peak pressure and rate of pressure rise with increase in ethanol ratio and is still superior for coated engine. Heat release pattern shows higher premixed combustion rate with the blends. Longer ignition delay and shorter combustion duration are found with all blends than neat diesel fuel.

  19. Experimental and theoretical analysis of the kinetics of the reaction of atomic bromine with 1,4-dioxane.

    Giri, Binod Raj; Roscoe, John M; González-García, Núria; Olzmann, Matthias

    2010-01-14

    The rate coefficient for the reaction of atomic bromine with 1,4-dioxane was measured from approximately 300 to 340 K using the relative rate method. Iso-octane and iso-butane were used as reference compounds, and the experiments were made in a bath of argon containing up to 210 Torr of O(2) at total pressures between 200 and 820 Torr. The rate coefficients were not affected by changes in pressure or O(2) concentration over our range of experimental conditions. The ratios of rate coefficients for the reaction of dioxane relative to the reference compound were put on an absolute basis by using the published absolute rate coefficients for the reference reactions. The variation of the experimentally determined rate coefficients with temperature for the reaction of Br with 1,4-dioxane can be given by k(1)(exp)(T) = (1.4 +/- 1.0) x 10(-11)exp[-23.0 +/- 1.8) kJ mol(-1)/(RT)] cm(3) molecule(-1) s(-1). We rationalized our experimental results in terms of transition state theory with molecular data from quantum chemical calculations. Molecular geometries and frequencies were obtained from MP2/aug-cc-pVDZ calculations, and single-point energies of the stationary points were obtained at CCSD(T)/CBS level of theory. The calculations indicate that the 1,4-dioxane + Br reaction proceeds in an overall endothermic addition-elimination mechanism via a number of intermediates. The rate-determining step is a chair-to-boat conformational change of the Br-dioxane adduct. The calculated rate coefficients, given by k(1)(calc)(T) = 5.6 x 10(-11)exp[-26.6 kJ mol(-1)/(RT)] cm(3) molecule(-1) s(-1), are in very good agreement with the experimental values. Comparison with results reported for the reactions of Br with other ethers suggests that this multistep mechanism differs significantly from that for abstraction of hydrogen from other ethers by atomic bromine. PMID:19848396

  20. Tetrakis(3-cyanopyridine-κN1bis(thiocyanato-κNcobalt(II 1,4-dioxane disolvate

    Stephan Diehr

    2011-12-01

    Full Text Available In the crystal structure of the title compound, {[Co(NCS2(C6H4N24]·2C4H8O2}, the CoII cations are octahedrally coordinated by two terminal N-bonded thiocyanate anions and four N-bonded 3-cyanopyridine ligands. The asymmetric unit consists of one CoII cation, which is located on a special position with site symmetry 2/m, one thiocyanate anion and one dioxane molecule, located on a crystallographic mirror plane, as well as one 3-cyanopyridine ligand in a general position. The crystal structure consists of discrete complexes of [Co(NCS2(3-cyanopyridine4], as well as two non-coordinating 1,4-dioxane solvent molecules which are disordered due to symmetry.

  1. Compatibility and thermal studies of blends of PMMA 350000 in 1,4-dioxane by ultrasonic technique

    Padmanaban, R.; Girivel, S.; Venkatramanan, K.

    2016-05-01

    The scientific and commercial progress in the area of polymer blends during the past two decades has been tremendous and was driven by the realization that new molecules are not always required to meet the needs of new materials and that blending can usually be implemented to meet the needs of new materials more rapidly and economically than the development of new chemistry. In the present study, activation energy of Poly(methyl methacrylate) (molar mass 350000) in 1,4-Dioxane is determined using viscometry technique. PMMA 350000 is blended with PS 35000 and the miscibility nature of the blend is analysed by ultrasonic velocity, density, viscosity and refractive index techniques at 303K. Molecular interaction properties of the blend is also discussed.

  2. Thermodynamics of the complexation between salicylaldehyde thiosemicarbazone with Cu2+ ion in methanol +1,4-dioxane binary solutions

    Biswas Rashmidipta

    2014-01-01

    Full Text Available The complexation reaction between salicylaldehyde thiosemicarbazone, abbreviated as STSC, with Cu2+ ion was studied in the binary mixtures of methanol + 1,4-dioxane binary by using UV-Visible spectrophotometric and conductometric methods at different temperatures. The formation constants (Kf for the 1:1 complex, Cu2+-STSC, were calculated from computer fitting of the absorbance and molar conductance data against various mole ratios (cM:cL or cL:cM in different binary solvent mixtures. A non-linear correlation was observed for the variation of logKf for the complex against the solvent compositions. Various thermodynamic parameters (ΔH, ΔS and ΔG for the formation of Cu2+-STSC complex were also determined from the temperature dependence of the stability constants (Kf. The results showed that the complexation reaction is affected by the nature and composition of the mixed solvents.

  3. Synthesis of Novel Homo-N-Nucleoside Analogs Composed of a Homo-1,4-Dioxane Sugar Analog and Substituted 1,3,5-Triazine Base Equivalents

    Qiang Yu

    2008-12-01

    Full Text Available Enantioselective syntheses from dimethyl tartrate of 1,3,5-triazine homo-N-nucleoside analogs, containing a 1,4-dioxane moiety replacing the sugar unit in natural nucleosides, were accomplished. The triazine heterocycle in the nucleoside analogs was further substituted with combinations of NH2, OH and Cl in the 2,4-triazine positions.

  4. The Natural Activation Ability of Subsurface Media During In-Situ Chemical Oxidation of 1,4-Dioxane

    Yan, N.; Brusseau, M. L. L.; Zhong, H.; Li, M.

    2015-12-01

    The ability of soils and sediments to produce in-situ activation of persulfate was investigated for treatment of 1,4-dioxane (dioxane). Experiments were conducted with both batch-reactor and column systems to examine reaction rates and activation mechanisms. Four soils and aquifer sediments were used. ICP-MS, SEM-EDS, and XRD analyses were used to characterize geochemical properties. For the batch experiments, degradation of dioxane was significantly greater in the presence of each of the four subsurface geomedia compared to the controls with no geomedia. This indicates that all four geomedia induced persulfate activation. The use of a binary oxidant system, with the addition of hydrogen peroxide, further enhanced dioxane degradation. It is hypothesized that iron associated with the geomedia is primarily responsible for activation, and that the degree of degradation enhancement relates in part to iron content. For the miscible-displacement experiments, slight retardation and minimal mass loss of persulfate was observed for transport in the column packed with the selected soil. And no dioxane degradation was observed, likely due to the low hydraulic residence time. Conversely, oxidant decomposition, sulfate generation, and dioxane degradation were observed upon injection of persulfate and H2O2. The results of this study indicate that geomedia can induce activation of persulfate to enhance in-situ chemical oxidation applications.

  5. Method 522 - Determination of 1,4-Dioxane in Drinking Water by Solid Phase Extraction (SPE) and Gas Chromatography Mass Spectrometry (GC/MS) with Selected Ion Monitoring (SIM)

    1,4-Dioxane has been identified as a probable human carcinogen and an emerging contaminant in drinking water. The National Exposure Research Laboratory (NERL) has developed a method for the analysis of 1,4-dioxane in drinking water at ng/L concentrations. The method consists of...

  6. Speeds of Sound and Excess Molar Volume for Binary Mixture of 1,4-Dioxane with 1-Heptanol at Five Temperatures

    Anil Kumar Koneti

    2014-01-01

    Full Text Available Speed of sound and density data for dilute liquid solutions of cyclic ether 1,4-dioxane with 1-heptanol was obtained using the Anton-Paar DSA 5000 at five temperatures  T = (298.15, 303.15, 308.15, 313.15, and 318.15 K at atmospheric pressure. The excess parameters were calculated from experimental data and fitted with a Redlich-Kister polynomial function and concluded the presence of weak molecular interactions.

  7. The effect of dissolved oxygen on the 1,4-dioxane degradation with TiO2 and Au-TiO2 photocatalysts

    In order to enhance the photocatalytic activity of TiO2, the recombination of photogenerated electron-hole pairs needs to be suppressed. Noble metals, e.g. Au nanoparticles, have been incorporated with TiO2 to efficiently separate charge carriers created in/on TiO2. On the other hand, dissolved oxygen (DO) in an aqueous solution was also known to scavenge the electrons, which avoid the recombination of electrons and holes. In this study, we investigated the combined system of Au nanoparticles incorporated with TiO2 and DO to gain insight into the relationship between them using a photocatalytic degradation of 1,4-dioxane. The rate constants of 1,4-dioxane photodegradation with respect to TiO2 catalysts with three different Au loadings, as well as DO levels, indicated the DO dependency is disproportional to the Au loading amount, implying that there is an overlapping function in capturing electrons between Au nanoparticles and DO.

  8. Characteristics of 1,4-Dioxane Degradation by Xanthobacter flavus DT8%Xanthobacter flavus DT8降解二噁烷的特性研究

    金小君; 陈东之; 朱润晔; 陈静; 陈建孟

    2012-01-01

    A strain DT8 was isolated from the activated sludge using culture enrichment technique, and subsequently identified as Xanthobacter flavus based on the analysis of morphological and physiological characteristics as well as cellular fatty acid composition and 16S rRNA sequence. X. flavus DT8 could effectively utilize 1,4-dioxane as the sole carbon and energy source, and was able to completely degrade 100 mg. L ^-1 substrate within 48 h. The values of biomass yield and energy discrepancy index were 0.62 g·g^-1 and 1.00, respectively, indicating that low energy share was dissipated. The optimum pH and temperature for 1,4-dioxane degradation were 7.0 and 34℃ , respectively. The degradation could also be performed in poor nutrition solution, e.g. the degradation ratio reached 65.6% even though in a 100-fold diluted medium. The induction process was not required in 1,4-dioxane degradation from this investigation. The characteristics of 1,4-dioxane degradation by X. flavus DT8 in direct metabolic mode was therefore revealed in this paper, and it will built a solid foundation for the application of biological purification of waste water and off-gas containing 1,4- dioxane.%对上海某医药厂污水站好氧池的活性污泥进行长期驯化,分离到1株能以二噁烷为唯一碳源和能源生长的菌株DT8.经生理生化、脂肪酸鉴定和16S rRNA序列分析,确定该菌株为黄黄色杆菌DT8(Xanthobacter flavus DT8).序批实验表明X.flavus DT8可于48 h内完全降解100 mg.L-1二噁烷,并可实现污染物的矿化.随着生物量的增加,该降解过程的细胞得率(以二噁烷计)为0.62 g.g-1,能量消耗系数(δe)为1.00,表明X.flavus DT8代谢二噁烷消耗的能量较少.研究不同温度、pH和营养条件对二噁烷降解的影响,发现二噁烷降解较适宜的温度和初始pH分别为34℃和7.0;在贫营养条件下,即无机盐培养基稀释100倍时,100 mg.L-1二噁烷于48 h的降解率达到65.6%.

  9. Simultaneous correlation of the excess enthalpy and W-shaped excess heat capacity of 1,4-dioxane+n-alkane systems by PRSV-HVOS CEOS

    SLOBODAN P. SERBANOVIC

    2003-01-01

    Full Text Available In this work the Peng-Robinson-Stryjek-Vera (PRSV equation of state coupled with the Huron-Vidal-Orbey-Sandler (HVOS rule was tested for the correlation of the excess enthalpy (HE and the excess heat capacity (cpE alone and simultaneously. The HVOS mixing rule incorporates the NRTL equation as the GE model. All calculations were performed using the linear and reciprocal forms of the temperature dependent parameters of the models. For all the evaluations the 1,4-dioxane+n-alkane systems were chosen having in mind the unusually W-shaped concentration dependence of cpE for these systems. The correlation of the HE and cpE data alone for all the investigated systems using four coefficients and for the simultaneous correlation of HE+cpE data using six coefficients of the temperature dependent parameters of the PRSV-HVOS models could be considered as being very satisfactory.

  10. Excess molar enthalpies of ternary mixtures of (methanol, ethanol + 2-propanol + 1,4-dioxane) at T=298.15 K

    Ternary excess molar enthalpies for the {x1CH3OH + x2i-C3H7OH + (1-x1-x2)c-C4H8O2} and {x1C2H5OH + x2i-C3H7OH + (1-x1-x2)c-C4H8O2} mixtures have been measured by a flow microcalorimeter at T=298.15 K and ambient pressure. The experimental results are correlated with a polynomial equation and used to construct constant excess enthalpy contours. Furthermore, the results have been compared with those calculated from a UNIQUAC associated-solution model. This model considers the self-association of like alcohols, multicross-association of unlike alcohols, and solvation between alcohols and 1,4-dioxane. The model with the association constants, solvation constants, and binary information alone predict the ternary excess molar enthalpies satisfactorily

  11. Spectrophotometric and conductometric study of the complexation of N-salicylidene-2-aminophenol with Cu2+ in methanol + 1,4-dioxane binary solutions

    Biswas Rashmidipta

    2014-01-01

    Full Text Available The complexation reaction between N-salicylidene-2-aminophenol, abbreviated as SAP, with Cu2+ ion was studied in binary mixtures of methanol and 1,4-dioxane by using conductometric and spectrophotometric method at different temperatures. The stability constants (Kf for the 1:1 complex, Cu2+-SAP, were calculated from computer fitting of absorbance and molar conductance data against various mole ratios (cM:cL or cL:cM in different binary solvent mixtures. A non-linear behaviour was observed for the variation of logKf for the complex against the solvent compositions. Various thermodynamic parameters (ΔH, ΔS and ΔG for the formation of Cu2+-SAP complex were determined from the temperature dependence of stability constants (Kf. The overall results showed that the complexation reaction is entropy driven and is affected by the nature and composition of the mixed solvents.

  12. SINGLE LANTHANUM TRIS(N-PHENYLETHYL-3,5-DI-t-BUTYLSALICYLALDIMINATO)S INITIATOR FOR RING-OPENING POLYMERIZATION OF 1,4-DIOXAN-2-ONE IN BULK

    Hao Zheng; Guo-rong Shen; Xu-feng Ni; Zhi-quan Shen

    2008-01-01

    A rare earth Schiff base complex:lanthanum tris(N-phenylethyl-3,5-di-t-butylsalicylaldiminato)s [La(OPEBS)3] was successfully applied as single component initiator for the ring-opening polymerization of 1,4-dioxan-2-one (PDO) in bulk.The influence of reaction conditions,such as polymerization temperature,the molar ratio of the monomer to initiator (M/I) on the monomer conversion and molecular weight of the polymer has been investigated.Poly(1,4-dioxan-2-one) with a viscosity-average molecular weight (My) of 8.29×104 and yield of 91.5% was prepared.

  13. Influence of temperature and organic solvents (isopropanol and 1,4-dioxane) on the micellization of cationic gemini surfactant (14-4-14).

    Das, Sibani; Naskar, Bappaditya; Ghosh, Soumen

    2014-04-28

    The micellar properties of gemini surfactant, tetramethylene-1,4-bis(dimethyltetradecylammonium bromide) (14-4-14) in binary aqueous mixtures of isopropanol (IP) and 1,4-dioxane (DO) were investigated by tensiometric, conductometric and microcalorimetric methods in the temperature range of 298 to 323 K. The values of both critical micelle concentration (cmc) and degree of dissociation increase with increasing temperature and concentration of cosolvent. The energetics of micellization was determined from the temperature dependence of critical micelle concentration values. The standard Gibbs free energy of micellization (ΔG) was found to be negative and the negative value decreases with both temperature and concentration of cosolvent. The Gibbs free energy of micellization (ΔG) is mainly controlled by tail transfer free energy. The enthalpy of micellization obtained from direct calorimetry, Gibbs-Helmholtz equation and van't Hoff methods are presented and compared. Entropic contribution is found to be larger than the enthalpy and for all the systems, an enthalpy-entropy compensation phenomenon was obtained. Some interfacial parameters, e.g., Gibbs surface excess (Γmax), minimum area per surfactant molecule (Amin), surface pressure (Πcmc) were been calculated. The fluorimetric technique was used to understand the microenvironment of the solution under the influence of cosolvent. The micellar aggregation number of 14-4-14 in a binary mixed solvent was also determined from fluorimetry using pyrene as a probe. Two fluorophores, fluorescein and curcumin delivered the information of the peripheral region of the micellar interface and palisade region. The self-diffusion coefficients of the micellar media were evaluated using the cyclic voltammetry (CV) method. Such multi-technique investigation provides a new look into the role of solvation in micellization. PMID:24668039

  14. Microcosm Studies to Evaluate Aerobic Cometabolism of Low Concentrations of 1,4-Dioxane by Isobutane-utilizing Microorganisms in the Presence of Chlorinated Solvent Co-contaminants

    Rolston, H. M.; Azizian, M.; Hyman, M. R.; Semprini, L.

    2015-12-01

    Due to its use as a stabilizer for chlorinated solvents, 1,4-dioxane (1,4D), a probable human carcinogen, is a common co-contaminant in solvent spills at industrial and military sites and landfills. Its persistence in large groundwater plumes at low concentrations makes it a relevant candidate for in-situ bioremediation via cometabolism. Microcosm studies are being performed to evaluate the capability of aerobic microorganisms to cometabolize mixtures of 1,4D and chlorinated solvents, such as trichloroethylene (TCE), 1,1,1-trichloroethane (1,1,1TCA), and 1,1-dichloroethene (1,1DCE), with isobutane as the primary substrate. Microcosms were constructed using aquifer solids from Fort Carson, Colorado, a site contaminated with 1,4D and TCE, to assess the isobutane uptake and transformation of 1,4D and chlorinated solvents by microorganisms native to the site. Additional microcosms were augmented with Rhodococcus rhodochrous, a bacterium shown to cometabolize 1,4D and chlorinated solvents. Results indicate that native microcosms cometabolized 1,4D upon stimulation with isobutane after a lag period of about 15 days. TCE was also transformed, but at significantly slower rates. The presence of 1,4D and TCE at 500 and 300 ppb, respectively, did not inhibit the growth of native microorganisms on isobutane, with isobutane uptake and 1,4D transformation occurring simultaneously. Bioaugmented microcosms transformed 1,4D immediately after inoculation with R. rhodochrous. Tests in bioaugmented microorganisms indicated that the presence of TCE at low concentrations inhibits but does not block the transformation of 1,4D. Results from the microcosms will be used to design field tests to be performed at Fort Carson. Additional microcosm studies will compare the stimulation of native and bioaugmented microcosms and the transformation of mixtures of 1,4D, 1,1,1TCA and 1,1DCE. Molecular methods will analyze the monoxygenase enzymes expressed in the native and bioaugmented microcosms.

  15. Densities and speeds of sound for binary mixtures of (1,3-dioxolane or 1,4-dioxane) with (2-methyl-1-propanol or 2-methyl-2-propanol) at the temperatures (298.15 and 313.15) K

    This paper reports densities and speeds of sound for the binary mixtures of (1,3-dioxolane or 1,4-dioxane) with (2-methyl-1-propanol or 2-methyl-2-propanol) at the temperatures (298.15 and 313.15) K. Excess volumes and excess isentropic compressibility coefficients have been calculated from experimental data and fitted by means of a Redlich-Kister type equation. The ERAS model has been used to calculate the excess volumes of the four systems at both temperatures

  16. Thermodynamics of the amalgam cells {Cs-amalgam|CsX (m)|AgX|Ag} (X=Cl, Br, I) and primary medium effects in (methanol+water) (acetonitrile+water), and (1,4-dioxane+water) solvent mixtures

    The potential difference E of the amalgam cell {CsxHg1-x|CsX (m)|AgX|Ag} (X=Cl, Br, I) has been measured as a function of the mole fraction xCs of Cs metal in amalgams and of the molality m of CsX in (methanol+water) (acetonitrile+water), and (1,4-dioxane+water) solvent mixtures containing up to 0.75 mass fraction of the organic component, at the temperature 298.15K. The respective standard molal potential differences Emo have been determined together with the relevant activity coefficients γ+/- as functions of the CsX molality. The found Emo values show a parabolic decrease with increasing proportion of the organic component in the solvent mixture. Analysis of the relevant primary medium effects upon CsX shows that the CsX transfer from the standard state in water to the standard state in the (aqueous+organic) mixture is always unfavoured, and the acetonitrile is the least unfavoured co-solvent studied. Analysis of the primary medium effect upon CsI in terms of Feakins and French's theory leads to a primary hydration number close to zero, which is consistent with the results of supplementary EXAFS experiments on Cs+ and I- in (acetonitrile+water) solvent mixtures

  17. Acoustical Studies of Schiff Bases in 1,4-dioxane and Dimethylformamide at 308.15K%用声学方法研究308.15K时Schiff碱在1,4-二氧杂环已环和二甲基甲酰胺溶液中的性质

    Shipra Baluja; Pranav Inamdar; Mayur Soni

    2004-01-01

    Density,viscosity and ultrasonic velocity of solutions of four Schiff basesin 1,4-dioxane and dimethylformamide(DMF)were measured at308.15K.Various acoustical properties such as specific impedance(Z),adiabatic compressibility(κs),Rao'smolar sound function(Rm),the van der Waals constant(b),molar compressibility(W),intermolecular free length(Lf),relaxation strength(r),solvation number(Sn),were calculated.The results are interpreted in terms of molecular interactions occurring in the solutions.

  18. 77 FR 7576 - Draft Toxicological Review of 1,4-Dioxane: In Support of Summary Information on the Integrated...

    2012-02-13

    ... Register Notices published August 31, 2011, (76 FR 54225) and September 16, 2011 (76 FR 57739). DATES: The... primarily via the Internet on the NCEA home page under the Recent Additions and Publications menus at http... Development, Research Triangle Park, NC 27711; telephone: (919) 541- 1964; facsimile: (919) 541-2985; or...

  19. Tetrakis(3-cyanopyridine-κN1)bis(thiocyanato-κN)cobalt(II) 1,4-dioxane disolvate

    Stephan Diehr; Susanne Wöhlert; Jan Boeckmann; Christian Näther

    2011-01-01

    In the crystal structure of the title compound, {[Co(NCS)2(C6H4N2)4]·2C4H8O2}, the CoII cations are octahedrally coordinated by two terminal N-bonded thiocyanate anions and four N-bonded 3-cyanopyridine ligands. The asymmetric unit consists of one CoII cation, which is located on a special position with site symmetry 2/m, one thiocyanate anion and one dioxane molecule, located on a crystallographic mirror plane, as well as one 3-cyanopyridine ligand in a general position. The crystal...

  20. Tetra­kis(3-cyano­pyridine-κN 1)bis­(thio­cyanato-κN)cobalt(II) 1,4-dioxane disolvate

    Diehr, Stephan; Wöhlert, Susanne; Boeckmann, Jan; Näther, Christian

    2011-01-01

    In the crystal structure of the title compound, {[Co(NCS)2(C6H4N2)4]·2C4H8O2}, the CoII cations are octa­hedrally coordinated by two terminal N-bonded thio­cyanate anions and four N-bonded 3-cyano­pyridine ligands. The asymmetric unit consists of one CoII cation, which is located on a special position with site symmetry 2/m, one thio­cyanate anion and one dioxane mol­ecule, located on a crystallographic mirror plane, as well as one 3-cyano­pyridine ligand in a general position. The crystal st...

  1. Crystal structure of N-[(8E-12-methyl-14-phenyl-10,13,14,16-tetraazatetracyclo[7.7.0.02,7.011,15]hexadeca-1(16,2,4,6,9,11(15,12-heptaen-8-ylidene]hydroxylamine 1,4-dioxane hemisolvate

    Shaaban K. Mohamed

    2015-02-01

    Full Text Available In the title solvate, C19H13N5O·0.5C4H8O2, the main molecule is almost planar (r.m.s. deviation for the non-H atoms = 0.066 Å. The hydroxylamine group is disordered over two orientations in a 0.761 (4:0.239 (4 ratio. The complete dioxane solvent molecule is generated by a crystallographic inversion centre. In the crystal, both disorder components of the hydroxylamine group form O—H...N hydrogen bonds to the same N-atom acceptor, thereby generating [010] chains. The chains encompass [010] channels occupied by the solvent molecules. Aromatic π–π stacking is also observed [shortest centroid–centroid separation = 3.3394 (19 Å].

  2. Discovery of N-(4-Fluoro-3-methoxybenzyl)-6-(2-(((2S,5R)-5-(hydroxymethyl)-1,4-dioxan-2-yl)methyl)-2H-tetrazol-5-yl)-2-methylpyrimidine-4-carboxamide. A Highly Selective and Orally Bioavailable Matrix Metalloproteinase-13 Inhibitor for the Potential Treatment of Osteoarthritis.

    Ruminski, Peter G; Massa, Mark; Strohbach, Joseph; Hanau, Cathleen E; Schmidt, Michelle; Scholten, Jeffrey A; Fletcher, Theresa R; Hamper, Bruce C; Carroll, Jeffery N; Shieh, Huey S; Caspers, Nicole; Collins, Brandon; Grapperhaus, Margaret; Palmquist, Katherine E; Collins, Joe; Baldus, John E; Hitchcock, Jeffrey; Kleine, H Peter; Rogers, Michael D; McDonald, Joseph; Munie, Grace E; Messing, Dean M; Portolan, Silvia; Whiteley, Laurence O; Sunyer, Teresa; Schnute, Mark E

    2016-01-14

    Matrix metalloproteinase-13 (MMP-13) is a zinc-dependent protease responsible for the cleavage of type II collagen, the major structural protein of articular cartilage. Degradation of this cartilage matrix leads to the development of osteoarthritis. We previously have described highly potent and selective carboxylic acid containing MMP-13 inhibitors; however, nephrotoxicity in preclinical toxicology species precluded development. The accumulation of compound in the kidneys mediated by human organic anion transporter 3 (hOAT3) was hypothesized as a contributing factor for the finding. Herein we report our efforts to optimize the MMP-13 potency and pharmacokinetic properties of non-carboxylic acid leads resulting in the identification of compound 43a lacking the previously observed preclinical toxicology at comparable exposures. PMID:26653735

  3. From Symmetric Glycerol Derivatives to Dissymmetric Chlorohydrins

    Gemma Villorbina

    2011-03-01

    Full Text Available The anticipated worldwide increase in biodiesel production will result in an accumulation of glycerol for which there are insufficient conventional uses. The surplus of this by-product has increased rapidly during the last decade, prompting a search for new glycerol applications. We describe here the synthesis of dissymmetric chlorohydrin esters from symmetric 1,3-dichloro-2-propyl esters obtained from glycerol. We studied the influence of two solvents: 1,4-dioxane and 1-butanol and two bases: sodium carbonate and 1-butylimidazole, on the synthesis of dissymmetric chlorohydrin esters. In addition, we studied the influence of other bases (potassium and lithium carbonates in the reaction using 1,4-dioxane as the solvent. The highest yield was obtained using 1,4-dioxane and sodium carbonate.

  4. Molar extinction coefficients of solutions of some organic compounds

    Singh, Kulwant; Sandhu, G. K.; Lark, B. S.

    2004-05-01

    Molar extinction coefficients of aqueous solutions of some organic compounds, viz. formamide (CH_{3}NO), N-methylformamide (C_{2}H_{5}NO), NN-dimethylformamide (C_{3}H_{7}NO), NN-dimethylacetamide (C_{4}H_{9}NO), 1,4-dioxane (C_{4}H_{8}O_{2}), succinimide (C_{4}H_{5}NO_{2}) and solutions of acetamide (C_{2}H_{5}NO) and benzoic acid (C_{7}H_{6}O_{2}) in 1,4-dioxane (C_{4}H_{8}O_{2}) have been determined by narrow beam gamma-ray transmission method at 81, 356, 511, 662, 1173 and 1332 keV. The experimental values of mass attenuation coefficients of these compounds have been used to calculate effective atomic numbers and electron densities. The additivity rule earlier used for aqueous solution has been extended to non-aqueous (1,4-dioxane) solutions.

  5. Crystal and molecular structures of glycolide and lactide: Association through CH···O hydrogen bonds

    The x-ray crystal structures of glycolide (1,4-dioxane-2.5-dione) and L(-)- and DL-lactide (3,6-dimethyl-1,4-dioxane-2,5-dione) are reported. The geometric parameters of the molecules, which have flattened boat conformations, were determined. Short intermolecular H···O distances 2.3-2.4 A between the methylene and carbonyl groups are considered as hydrogen bonds. This interpretation is supported by spectroscopic data and quantum-chemical calculations

  6. Cellulose decomposition behavior in hot-compressed aprotic solvents

    BAO GuiRong; Shiro SAKA; WANG Hua

    2008-01-01

    Microcrystalline cellulose (avicel) is treated in hot-compressed aprotic solvents, sulfolane and 1,4-dioxane, using a batch-type reaction system with a molten tin bath in a range from 290 to 390℃. The corresponding densities of the solvent are 0.25-1.26 g/cm3 and 0.21-1.03 g/cm3 for sulfolane and 1,4-dioxane, respectively. As a result, in both solvents, more than 90% of cellulose is found to be de-composed to the solvent-soluble portion in which levoglucosan is the main component with the high-est yield of about 35% on original cellulose basis. The decomposition rate to levoglucosan is, however, faster in sulfolane than in 1,4-dioxane, while levoglucosan is more stable in 1,4-dioxane. In addition, its yield is found to be solvent-density dependent to be highest around 0.4-0.5 g/cm3 for both solvents. To elucidate these decomposition behaviors, the results obtained in this study with aprotic solvents are compared with protic solvents such as water and methanol in previous works.

  7. Cellulose decomposition behavior in hot-compressed aprotic solvents

    Shiro; SAKA

    2008-01-01

    Microcrystalline cellulose (avicel) is treated in hot-compressed aprotic solvents,sulfolane and 1,4-dioxane,using a batch-type reaction system with a molten tin bath in a range from 290 to 390℃. The corresponding densities of the solvent are 0.25-1.26 g/cm3 and 0.21-1.03 g/cm3 for sulfolane and 1,4-dioxane,respectively. As a result,in both solvents,more than 90% of cellulose is found to be de-composed to the solvent-soluble portion in which levoglucosan is the main component with the high-est yield of about 35% on original cellulose basis. The decomposition rate to levoglucosan is,however,faster in sulfolane than in 1,4-dioxane,while levoglucosan is more stable in 1,4-dioxane. In addition,its yield is found to be solvent-density dependent to be highest around 0.4-0.5 g/cm3 for both solvents. To elucidate these decomposition behaviors,the results obtained in this study with aprotic solvents are compared with protic solvents such as water and methanol in previous works.

  8. 2-[(4-Bromophenyliminomethyl]-5-pentadecylphenol

    Basavaraj Padmashali

    2012-08-01

    Full Text Available 2-[(4-Bromophenyliminomethyl]-5-pentadecylphenol has been synthesized by reaction of 2-hydroxy-4-pentadecylbenzaldehyde with 4-bromoaniline in 1,4-dioxane and its IR, 1H-NMR, 13C-NMR and MS spectroscopic data are presented.

  9. Effect of the Solvent on the Microstructure of Bi2Te3 Obtained Solvothermal Microwave-assisted Synthesis

    R.A. Lyubushkin

    2014-04-01

    Full Text Available In the present work, nanoparticles and nanowires have been prepared by solvothermal microwave-assisted synthesis using isopropyl alcohol, dimethylformamide (DMF and 1,4-dioxane respectively as the solvents. The microstructures of the synthesized powders have been characterized and the relationship with the solvent has been investigated.

  10. Surface-modified functionalized polycaprolactone scaffolds for bone repair

    Jensen, Jonas; Rölfing, Jan Hendrik Duedal; Svend Le, Dang Quang;

    2014-01-01

    -PCL). Afterward, the FDM-PCL scaffolds were infused with a mixture of PCL, water, and 1,4-dioxane and underwent a thermal-induced phase separation (TIPS) followed by lyophilization. The TIPS process lead to a nanoporous structure shielded by the printed microstructure (NSP-PCL). Sixteen Landrace pigs were divided...

  11. 5-Pentadecyl-2-((p-tolyliminomethylphenol

    Amorn Petsom

    2013-07-01

    Full Text Available 5-Pentadecyl-2-((p-tolyliminomethylphenol has been synthesized by reaction of 2-hydroxy-4-pentadecylbenzaldehyde with 4-amino-1-methyl-aniline in 1,4-dioxane under reflux. The structure of the synthesized compound was assigned on the basis of elemental analysis, UV, IR, 1H-NMR, 13C-NMR and mass spectral data.

  12. Laboratory shake flask batch tests can predict field biodegradation of aniline in the Rhine

    Toräng, Lars; Reuschenbach, P.; Müller, B.; Nyholm, Niels

    2001-01-01

    calculated from measurements of conductivity, sulfate and a non-readily biodegradable substance, 1,4-dioxane. Compensating dilution, field first-order degradation rate constants downstream the discharge of BASF were estimated at 1.8 day(-1) for two different dates with water temperatures of 21.9 and 14...

  13. A novel convenient preparation of dihydroxyacetone phosphate and its use in enzymatic aldol reactions

    Effenberger, Franz; Straub, Alexander

    1987-01-01

    A new preparation of the stable barium salt of 2,5-bis(phosphonooxymethyl)-2,5-diethoxy-1,4-dioxane Ba-Image is described, which by treatment with DOWEX 50 H+ gives dihydroxyacetone phosphate (DHAP) in high yield. DHAP prepared by this method was used for aldolase-catalyzed condensations.

  14. Solid–liquid equilibria for binary and ternary systems with the Cubic-Plus-Association (CPA) equation of state

    Fettouhi, André; Thomsen, Kaj

    2010-01-01

    A systematic investigation of the CPA model's performance within solid-liquid equilibria (SLE) in binary mixtures (methane + ethane, methane + heptane, methane + benzene, methane + CO2, ethane + heptane, ethane + CO2, 1-propanol + 1,4-dioxane, ethanol + water, 2-propanol + water) is presented. Th...

  15. Quantum Cascade Laser-Based Photoacoustic Spectroscopy for Trace Vapor Detection and Molecular Discrimination

    Almon Fisher

    2010-03-01

    Full Text Available We report on the development of a microelectromechanical systems (MEMS-scale photoacoustic sensor for the detection of trace gases. A mid-infrared quantum cascade laser (QCL was used to determine detection limits for acetic acid, acetone, 1,4-dioxane, and vinyl acetate. The source was continuously tunable from 1015 cm-1 to 1240 cm-1, allowing for the collection of photoacoustic vibrational spectra for these gases. Exceptional agreement between the measured photoacoustic spectra and the infrared spectra for acetic acid, acetone, 1,4-dioxane, and vinyl acetate was observed. Partial least-squares (PLS regression was used to develop an algorithm for classification of these compounds based solely on photoacoustic spectra.

  16. Quantum Cascade Laser-Based Photoacoustic Spectroscopy for Trace Vapor Detection and Molecular Discrimination

    Holthoff, Ellen; Bender, John; Pellegrino, Paul; Fisher, Almon

    2010-01-01

    We report on the development of a microelectromechanical systems (MEMS)-scale photoacoustic sensor for the detection of trace gases. A mid-infrared quantum cascade laser (QCL) was used to determine detection limits for acetic acid, acetone, 1,4-dioxane, and vinyl acetate. The source was continuously tunable from 1015 cm−1 to 1240 cm−1, allowing for the collection of photoacoustic vibrational spectra for these gases. Exceptional agreement between the measured photoacoustic spectra and the infrared spectra for acetic acid, acetone, 1,4-dioxane, and vinyl acetate was observed. Partial least-squares (PLS) regression was used to develop an algorithm for classification of these compounds based solely on photoacoustic spectra. PMID:22294910

  17. Near-infrared Raman spectroscopy using a diode laser and CCD detector for tissue diagnostics

    This paper surveys the possibility to observe high-quality NIR Raman spectra of both fluorescent and non-fluorescent samples with the use of a diode laser, a fibre optic sample, a single spectrometer and a charge-coupled device (CCD) detector. A shifted excitation difference technique was implemented for removing the broad-band fluorescence emission from Raman spectra of the highly fluorescent samples. Raman spectra of 1.4-dioxane, toluene, rhodamine 6G, and HITCI in the 640 to 1840 cm-1 spectral region and 1.4-dioxane and toluene in the 400 to 3400 cm-1 spectral region have been recorded. The results open the field of sensitive tissue characterisation and the possibility of optical biopsy in vivo by using NIR Raman spectroscopy with fibre optic sampling, a single spectrometer, and a CCD detector

  18. Metal-coordination-driven mixed ligand binding in supramolecular bisporphyrin tweezers.

    Ikbal, Sk Asif; Dhamija, Avinash; Rath, Sankar Prasad

    2015-09-25

    Mg(II)bisporphyrin has been used as an efficient host for the selective binding of guest ligands. In the presence of heterogeneous guest pairs, 2-aminopyrimidine/pyrazine and 2-aminopyrimidine/1,4-dioxane, 2-aminopyrimidine is bound selectively inside the bisporphyrin cavity whereas pyrazine/1,4-dioxane is bound outside to produce 1D mixed ligand polymers. UV-vis, (1)H NMR spectra and X-ray structure confirm such a selective and orthogonal binding of the guest ligands. The mixed ligand polymer has been synthesized just by mixing the host and guests in one pot and easily isolated as a solid in nearly quantitative yield due to its high stability. PMID:26256242

  19. Electron-ion dissociative recombination rate constants relevant to the Titan atmosphere and the Interstellar Medium

    Osborne, David; Lawson, Patrick; Adams, Nigel, E-mail: ngadams@uga.edu [University of Georgia, Department of Chemistry, 101 Cedar St., Athens, Georgia 30602 (United States)

    2014-01-21

    Following the arrival of Cassini at Titan in 2004, the Titan atmosphere has been shown to contain large complex polycyclic-aromatic hydrocarbons. Since Cassini has provided a great deal of data, there exists a need for kinetic rate data to help with modeling this atmosphere. One type of kinetic data needed is electron-ion dissociative recombination (e-IDR) rate constants. These data are not readily available for larger compounds, such as naphthalene, or oxygen containing compounds, such as 1,4 dioxane or furan. Here, the rate constants for naphthalene, 1,4 dioxane, and furan have been measured and their temperature dependencies are determined when possible, using the University of Georgia's Variable Temperature Flowing Afterglow. The rate constants are compared with those previously published for other compounds; these show trends which illustrate the effects which multi-rings and oxygen heteroatoms substitutions have upon e-IDR rate constants.

  20. Solution small-angle x-ray scattering as a screening and predictive tool in the fabrication of asymmetric block copolymer membranes

    Dorin, Rachel Mika

    2012-05-15

    Small-angle X-ray scattering (SAXS) analysis of the diblock copolymer poly(styrene-b-(4-vinyl)pyridine) in a ternary solvent system of 1,4-dioxane, tetrahydrofuran, and N,N-dimethylformamide, and the triblock terpolymer poly(isoprene-b-styrene-b-(4-vinyl)-pyridine) in a binary solvent system of 1,4-dioxane and tetrahydrofuran, reveals a concentration-dependent onset of ordered structure formation. Asymmetric membranes fabricated from casting solutions with polymer concentrations at or slightly below this ordering concentration possess selective layers with the desired nanostructure. In addition to rapidly screening possible polymer solution concentrations, solution SAXS analysis also predicts hexagonal and square pore lattices of the final membrane surface structure. These results suggest solution SAXS as a powerful tool for screening casting solution concentrations and predicting surface structure in the fabrication of asymmetric ultrafiltration membranes from self-assembled block copolymers. (Figure presented) © 2012 American Chemical Society.

  1. Morphology phase diagram of ultrathin anatase TiO2 films templated by a single PS-b-PEO block copolymer.

    Cheng, Ya-Jun; Gutmann, Jochen S

    2006-04-12

    Ultrathin TiO2 films showing rich morphologies are prepared on Si(100) substrates using sol-gel chemistry coupled with an amphilic polystyrene-block-poly(ethylene oxide) (PS-b-PEO) diblock copolymer as a structure-directing agent. The block copolymer undergoes a good-poor solvent pair induced phase separation in a mixed solution of 1,4-dioxane, concentrated hydrochloric acid (HCl), and titanium tetraisopropoxide (TTIP). By adjusting the weight fractions of 1,4-dioxane, HCl, and TTIP, inorganic block copolymer composite films containing a variety of different morphologies are obtained. On the basis of the results a ternary phase diagram of the morphologies is mapped. By calcination, anatase TiO2 films are achieved. The morphologies and crystallographic phase of the films are studied with AFM, SEM, and XRD, respectively, and the formation mechanisms of the different morphologies are discussed. PMID:16594703

  2. Synthese funktionalisierter Phenolpolymere durch HRP-katalysierte Polyrekombination

    Reihmann, Matthias

    2002-01-01

    ZUSAMMENFASSUNG: Die durch das Enzym Horseradish Peroxidase katalysierte oxidative Polymerisation substituierter Phenole gewährt einen bequemen Zugang zu funktionalisierten Phenolpolymeren, deren Anwendung als Ersatz für konventionelle Phenol-Formaldehyd-Harze zur Zeit intensiv erforscht wird. Zur Zeit werden Polymerisation dieser Art in Mischungen aus organischen Lösungsmitteln (z.B. 1,4-Dioxan) und Puffer durchgeführt. Im Rahmen dieser Arbeit wurde eine HRP-katalysierte Phenolpolymerisation...

  3. Controlling the crystallization of porous organic cages: molecular analogs of isoreticular frameworks using shape-specific directing solvents

    Hasell, Tom; Culshaw, Jamie L.; Chong, Samantha Y.; Little, Marc A.; Jelfs, Kim E.; Pyzer-Knapp, Edward O.; Shepherd, Hilary; Adams, Dave J.; Day, Graeme M.; Cooper, Andrew I.

    2014-01-01

    Small structural changes in organic molecules can have a large influence on solid-state crystal packing, and this often thwarts attempts to produce isostructural series of crystalline solids. For metal–organic frameworks and covalent organic frameworks, this has been addressed by using strong, directional intermolecular bonding to create families of isoreticular solids. Here, we show that an organic directing solvent, 1,4-dioxane, has a dominant effect on the lattice energy for a series of or...

  4. An Investigation of the Behavior of Solvent based Polycaprolactone ink for Material Jetting

    Yinfeng He; Ricky D. Wildman; Chris J. Tuck; Steven D. R. Christie; Steven Edmondson

    2016-01-01

    An initial study of processing bioresorbable polycaprolactone (PCL) through material jetting was conducted using a Fujifilm Dimatix DMP-2830 material printer. The aim of this work was to investigate a potential solvent based method of jetting polycaprolactone. Several solvents were attempt to prepared PCL solvent based ink and 1, 4-dioxane was chosen with the consideration of both solubility and safety. The morphology of PCL formed under different substrate temperatures, droplet spacings were...

  5. Duloxetine hydrochloride

    Mohan Bhadbhade

    2009-09-01

    Full Text Available The title compound [systematic name: N-methyl-3-(1-naphthyloxy-3-(2-thienylpropan-1-aminium chloride], C18H20NOS+·Cl−, was crystallized from 1,4-dioxane. Twofold rotational disorder exhibited by the thiophene ring in a 0.580 (5:0.420 (5 ratio represents two different conformations of the molecule that exist in the same crystal form. The crystal structure contains strong N—H...Cl hydrogen bonds.

  6. A Method for Synthesizing Partially Substituted Cucurbit[n]uril

    Rodney J. Blanch

    2003-01-01

    Full Text Available A novel approach to cucurbituril synthesis is described where partial substitution is introduced into cucurbit[n]uril. The identification of homologues (and their substitution in reaction mixtures is achieved by a combination of ESMS and the use of the molecular probes (guests 1,4-dioxane and 1,9-octanediamine. A unique symmetrical hexamethylcucurbit[3,3]uril, the major product, was isolated and characterized.

  7. (2-Chlorophenyl-3-methylchromeno[2,3-c]pyrazol-4(1H-one

    Wolfgang Holzer

    2010-03-01

    Full Text Available The title compound was prepared by treatment of 1-(2-chlorophenyl-3-methyl-2-pyrazolin-5-one with 2-chlorobenzoyl chloride / Ca(OH2 in 1,4-dioxane and subsequent cyclization of the thus obtained 4-aroyl-5-hydroxypyrazole with sodium hydride in dry DMF. Detailed spectroscopic data (1H NMR, 13C NMR, 15N NMR, IR, MS are presented.

  8. 3-Methyl-1-phenyl-1H-pyrazol-5-yl 2-Bromo-3-furan-carboxylate

    Karin Schalle

    2009-07-01

    Full Text Available The reaction of 3-methyl-1-phenyl-2-pyrazolin-5-one and 2-bromo-3-furoyl chloride in the presence of Ca(OH2 in 1,4-dioxane gave the title compound. The latter was also obtained in much higher yield upon reaction of the starting materials in the system dichloromethane / triethylamine. Detailed spectroscopic data (1H NMR, 13C NMR, 15N NMR, IR, MS are presented.

  9. Maleimide-functionalized closo-dodecaborate albumin conjugates (MID-AC): Unique ligation at cysteine and lysine residues enables efficient boron delivery to tumor for neutron capture therapy.

    Kikuchi, Shunsuke; Kanoh, Daisuke; Sato, Shinichi; Sakurai, Yoshinori; Suzuki, Minoru; Nakamura, Hiroyuki

    2016-09-10

    Maleimide-conjugating closo-dodecaborate sodium form 5c (MID) synthesized by the nucleophilic ring-opening reaction of closo-dodecaborate-1,4-dioxane complex 2 with tetrabutylammonium (TBA) azide was found to conjugate to free SH of cysteine and lysine residues in BSA under physiological conditions, forming highly boronated BSA that showed high and selective accumulation in tumor and significant tumor growth inhibition in colon 26 tumor-bearing mice subjected to thermal neutron irradiation. PMID:27422608

  10. Synthesis and Determination of Absolute Configuration of a Divergent Polyhydroxy Enyne Compound

    Zhi Jie XUE; Yuan Chao LI

    2005-01-01

    Polyhydroxy enyne compound (+)-(1'S, 2R, 3S, 5S, 6S)-5,6-dimethoxy-5, 6-dimethyl-2-(1'-hydroxylpropyl-2-ne)-3-vinyl-1,4-dioxane has been synthesized from D-(-)-tartaric acid. A new chiral center was established by nucleophilic addition with 87% de. The modified Mosher's method was employed to confirm the absolute configuration of 17, which assigned the S-configuration at the new chiral center.

  11. Two new compounds from the marine Nigrospora sphaerica.

    Zhang, Qi-Hui; Tian, Li; Zhou, Lian-Di; Zhang, Ying; Li, Zhi-Feng; Hua, Hui-Ming; Pei, Yue-Hu

    2009-11-01

    Two new compounds, 1-(5-oxotetrahydrofuran-2-yl)ethyl 2-phenylacetate (1) and 3-hydroxybutan-2-yl 2-hydroxy-3-phenylpropanoate (2), along with three known compounds, harzialactone A (3), benzeneethanol 4-hydroxy-1-acetate (4), and 1,4-dioxane-2,5-dione-3,6-bis(penylmethyl)-homopolymer (5), have been isolated from the fungus Nigrospora sphaerica. Their structures were determined on the basis of chemical and spectroscopic methods. PMID:20183261

  12. Quantum Cascade Laser-Based Photoacoustic Spectroscopy for Trace Vapor Detection and Molecular Discrimination

    Almon Fisher; Paul Pellegrino; John Bender; Ellen Holthoff

    2010-01-01

    We report on the development of a microelectromechanical systems (MEMS)-scale photoacoustic sensor for the detection of trace gases. A mid-infrared quantum cascade laser (QCL) was used to determine detection limits for acetic acid, acetone, 1,4-dioxane, and vinyl acetate. The source was continuously tunable from 1015 cm-1 to 1240 cm-1, allowing for the collection of photoacoustic vibrational spectra for these gases. Exceptional agreement between the measured photoacoustic spectra and the infr...

  13. Copper-Catalyzed Oxidative C-H Amination of Tetrahydrofuran with Indole/Carbazole Derivatives.

    Yang, Qingjing; Choy, Pui Ying; Fu, Wai Chung; Fan, Baomin; Kwong, Fuk Yee

    2015-11-01

    A simple α-C-H amination of cyclic ether with indole/carbazole derivatives has been accomplished by employing copper(II) chloride/bipy as the catalyst system. In the presence of the di-tert-butyl peroxide oxidant, cyclic ethers such as tetrahydrofuran, 1,4-dioxane, and tetrahydropyran successfully undergo C-H/N-H cross dehydrogenative coupling (CDC) with various carbazole or indole derivatives in good-to-excellent yields. PMID:26485515

  14. Biodegradable and macroporous polylactide implants for cell transplantation : 1. Preparation of macroporous polylactide supports by solid-liquid phase separation

    Schugens, Ch; Maquet, Véronique; Grandfils, Christian; Jérôme, Robert; Teyssié, Philippe

    1996-01-01

    Freeze-drying of polylactide solutions in 1,4-dioxane has been studied as a way to produce microcellular foams. The thermally induced phase separation has been studied in relation to several processing and formulation parameters. The effects of polymer concentration, chain stereoregularity, polymer molecular weight and cooling rate have been investigated in connection with the porous morphology and the physico-mechanical characteristics of the final foams. As a rule, bundles of channels are f...

  15. Dielectric relaxation and hydrogen bonding studies of 1,3-propanediol–dioxane mixtures using time domain reflectometry technique

    Madhukar N Shinde; Ravindra B Talware; Pravin G Hudge; Yogesh S Joshi; Ashok C Kumbharkhane

    2012-02-01

    The complex permittivity, static dielectric constant and relaxation time for 1,3-propanediol, 1,4-dioxane and their mixtures have been studied using time domain reflectometry (TDR). The excess permittivity, excess inverse relaxation time and Kirkwood correlation factor have also been determined at various concentrations of dioxane. Hydrogen bonded theory was applied to compute the correlation terms for the mixtures. The Bruggeman model for the nonlinear case has been fitted to the dielectric data for mixtures.

  16. Proposing nanofiltration as acceptable barrier for organic contaminants in water reuse

    Yangali-Quintanilla, Victor

    2010-10-01

    For water reuse applications, " tight" nanofiltration (NF) membranes (of polyamide) as an alternative to reverse osmosis (RO) can be an effective barrier against pharmaceuticals, pesticides, endocrine disruptors and other organic contaminants. The use of RO in existing water reuse facilities is addressed and questioned, taking into consideration that tight NF can be a more cost-effective and efficient technology to target the problem of organic contaminants. It was concluded that tight NF is an acceptable barrier for organic contaminants because its removal performance approaches that of RO, and because of reduced operation and maintenance (O&M) costs in long-term project implementation. Average removal of neutral compounds (including 1,4-dioxane) was about 82% and 85% for NF and RO, respectively, and average removal of ionic compounds was about 97% and 99% for NF and RO, respectively. In addition, " loose" NF after aquifer recharge and recovery (ARR) can be an effective barrier against micropollutants with removals over 90%. When there is the presence of difficult to remove organic contaminants such as NDMA and 1,4-dioxane; for 1,4-dioxane, source control or implementation of treatment processes in wastewater treatment plants will be an option; for NDMA, a good strategy is to limit its formation during wastewater treatment, but there is evidence that biodegradation of NDMA can be achieved during ARR. © 2010 Elsevier B.V.

  17. A rapid spectrophotometric method for the determination of mercury in environmental, biological, soil and plant samples using diphenylthiocarbazone

    AHMED, M. Jamaluddin; Alam, Md Shah

    2003-01-01

    A simple, sensitive and highly selective direct spectrophotometric method for the determination of trace levels of mercury(II) in various samples is described. Diphenylthiocarbazone (dithizone) reacts in slightly acidic 50% aqueous 1,4-dioxane media (0.18–1.80 M sulphuric acid) with mercury(II) to give an orange chelate which has an absorption maximum at 488 nm. The average molar absorption co-efficient and Sandell's sensitivity were found to be 2.5×104l mol−1 cm−1 and 0.015 μg of Hg(II) cm−2...

  18. Desenvolvimento de um método de MEFS com CG-DIC para determinação de 1,4 dioxana em amostras de cosméticos

    Silva Fernando C.

    2001-01-01

    Full Text Available A headspace solid-phase microextraction (HS-SPME for the determination of 1,4 dioxane in cosmetics by gas chromatography is described. A manual SPME holder with 85 µm polyacrylate coating is utilized. The method is determined to have good resolution, satisfactory linerity (correlation coefficient r=0.997 for 0.20-10.00 mg Kg-1 range, a relative standard deviation of 6.3% and a detection limit of 5.00 µg Kg-1. Some cosmectic products were analyzed.

  19. Surface-modified functionalized polycaprolactone scaffolds for bone repair: In vitro and in vivo experiments

    Jensen, Jonas; Rolfing, Jan Hendrik Duedal; Svend Le, Dang Quang; Kristiansen, Asger Albæk; Nygaard, Jens Vinge; Bjerre Hokland, Lea; Bendtsen, Michael; Kassem, Moustapha; Lysdahl, Helle; Bunger, Cody Eric

    2014-01-01

    A porcine calvaria defect study was carried out to investigate the bone repair potential of three-dimensional (3D)-printed poly-ε-caprolactone (PCL) scaffolds embedded with nanoporous PCL. A microscopic grid network was created by rapid prototyping making a 3D-fused deposition model (FDM-PCL). Afterward, the FDM-PCL scaffolds were infused with a mixture of PCL, water, and 1,4-dioxane and underwent a thermal-induced phase separation (TIPS) followed by lyophilization. The TIPS process lead to a...

  20. New enzymatically polymerized copolymers from 4-tert-butylphenol and 4-ferrocenylphenol and their modification and inclusion complexes with β-cyclodextrin

    Adam Mondrzyk

    2012-12-01

    Full Text Available The enzymatically catalyzed synthesis of a copolymer of 4-tert-butylphenol and 4-ferrocenylphenol by horse radish peroxidase (HRP in the presence of H2O2 in a 1,4-dioxane/water system is described. Furthermore, polymer-analogous alkylation of the free hydroxy groups and subsequent click reaction with mono-6-azido-6-desoxy-β-cyclodextrin (N3-β-CD was carried out. The formation of inter- and intramolecular inclusion complexes was investigated by DLS measurement.

  1. A new ether-based electrolyte for dendrite-free lithium-metal based rechargeable batteries.

    Miao, Rongrong; Yang, Jun; Xu, Zhixin; Wang, Jiulin; Nuli, Yanna; Sun, Limin

    2016-01-01

    A new ether-based electrolyte to match lithium metal electrode is prepared by introducing 1, 4-dioxane as co-solvent into lithium bis(fluorosulfonyl)imide/1,2-dimethoxyethane solution. Under the synergetic effect of solvents and salt, this simple liquid electrolyte presents stable Li cycling with dendrite-free Li deposition even at relatively high current rate, high coulombic efficiency of ca. 98%, and good anodic stability up to ~4.87 V vs Li RE. Its excellent performance will open up a new possibility for high energy-density rechargeable Li metal battery system. PMID:26878890

  2. An Investigation of the Behavior of Solvent based Polycaprolactone ink for Material Jetting

    He, Yinfeng; Wildman, Ricky D.; Tuck, Chris J.; Christie, Steven D. R.; Edmondson, Steven

    2016-02-01

    An initial study of processing bioresorbable polycaprolactone (PCL) through material jetting was conducted using a Fujifilm Dimatix DMP-2830 material printer. The aim of this work was to investigate a potential solvent based method of jetting polycaprolactone. Several solvents were used to prepare a PCL solvent based ink and 1, 4-dioxane was chosen with the consideration of both solubility and safety. The morphology of PCL formed under different substrate temperatures, droplet spacings were investigated. Multi-layer PCL structures were printed and characterized. This work shows that biodegradable polycaprolactone can be processed through material jetting.

  3. 4-Amino-13-(1-naphthyl-[2,2]paracyclophane

    Yudao Ma

    2008-04-01

    Full Text Available The title compound [systematic name: 12-amino-42-(1-naphthyl-1,4(1,4-dibenzenacyclohexaphane], C26H23N, was synthesized from 4-amino-13-bromo-[2,2]paracyclophane and 1-naphthaleneboronic acid in the presence of 1,4-dioxane. It is a new cyclophane-derived compound which can be regarded as a prospective ligand for asymmetric synthesis and catalysis. The benzene rings of the paracyclophane units are very slightly deformed from planarity as shallow boats.

  4. Synthesis and biological activity of some heterocyclic compounds containing quinoxaline and coumarin moieties

    M. E. ABD EL-FATTAH

    2000-02-01

    Full Text Available 2,3-Dichloroquinoxaline (2 condensed with 7,8-dihydroxy-4-methylcoumarin to give the 1,4-dioxane derivative 4. 2.3-Dichloroquinoxaline (2 reacted with 4-hydroxycoumarin, 7-hydroxy-4-methylcoumarin and acyl hydrazide 13 to give either the 2,3-(dicoumarin-4-yloxyquinoxaline (6 or the 2,3-di-(4-methylcoumarin-7-yloxyquinoxaline (7 or the 2-chloro-3-(coumarin-4-yloxyquinoxaline (8 or the 2-chloro-3-(4-methylcoumarin-7-yloxy quinoxaline (9 or the ditriazoloquinoxaline 14 or the oxa-diazinoquinoxaline 16, depending on the relative ratios of the reactants and the reaction conditions.

  5. On the activity loss of hydrolases in organic solvents: II. a mechanistic study of subtilisin Carlsberg

    Ferrer Amaris

    2006-12-01

    Full Text Available Abstract Background Enzymes have been extensively used in organic solvents to catalyze a variety of transformations of biological and industrial significance. It has been generally accepted that in dry aprotic organic solvents, enzymes are kinetically trapped in their conformation due to the high-energy barrier needed for them to unfold, suggesting that in such media they should remain catalytically active for long periods. However, recent studies on a variety of enzymes demonstrate that their initial high activity is severely reduced after exposure to organic solvents for several hours. It was speculated that this could be due to structural perturbations, changes of the enzyme's pH memory, enzyme aggregation, or dehydration due to water removal by the solvents. Herein, we systematically study the possible causes for this undesirable activity loss in 1,4-dioxane. Results As model enzyme, we employed the protease subtilisin Carlsberg, prepared by lyophilization and colyophilization with the additive methyl-β-cyclodextrin (MβCD. Our results exclude a mechanism involving a change in ionization state of the enzyme, since the enzyme activity shows a similar pH dependence before and after incubation for 5 days in 1,4-dioxane. No apparent secondary or tertiary structural perturbations resulting from prolonged exposure in this solvent were detected. Furthermore, active site titration revealed that the number of active sites remained constant during incubation. Additionally, the hydration level of the enzyme does not seem to affect its stability. Electron paramagnetic resonance spectroscopy studies revealed no substantial increase in the rotational freedom of a paramagnetic nitroxide inhibitor bound to the active site (a spin-label during incubation in neat 1,4-dioxane, when the water activity was kept constant using BaBr2 hydrated salts. Incubation was also accompanied by a substantial decrease in Vmax/KM. Conclusion These results exclude some of the

  6. From Spherical Mesopores to Worm-Shaped Mesopores: Morphology Transition in Titania-Polystyrene- b -poly(ethylene oxide) Composite Films with Increasing Sol-Gel Reaction Time

    Cheng, Ya-Jun; Zhou, Shaoying; Gutmann, Jochen S; Wolkenhauer, Markus; Bumbu, Gina-Gabriela; Lenz, Sebastian; Memesa, Mine; Nett, Sebastian; Emmerling, Sebastian; Steffen, Werner; Roth, Stephan V.

    2014-01-01

    A morphology transition from spherical mesopores to worm-shaped mesopores within titania block copolymer composite thin films has been observed by varying the sol–gel reaction time from 40 min to 48 h in the four-component templating system of polystyrene-$\\mathit{b}$-poly(ethylene oxide) (PS-$\\mathit{b}$-PEO), 1,4-dioxane, concentrated HCl, and titanium tetraisopropoxide (TTIP) with a PS-$\\mathit{b}$-PEO mass concentration of 0.25 wt.-%. The impact of the sol–gel reaction time on the local s...

  7. A novel methyl pyridinium salt for the detection of water content in organic solvents

    ZHANG Mingyu

    2014-12-01

    Full Text Available A novel pyridinium salt,TM was synthesized from 2,6-dimethylpyridin.TM exhibits pronounced negative solvatochromism and possesses high absorption spectral sensitivities to water content changes.TM could be used to measure the water content in organic solvents such as THF,1,4-dioxane,acetone,and methanol.The detection limit was 0.04% for THF.The calibration curve for the determination of water in THF was obtained.TM exhibited high selectivity and sensitivity in the absorbance detection of water in organic solvents.

  8. Facile synthesis of α-hydroxy carboxylic acids from the corresponding α-amino acids

    Stuhr-Hansen, Nicolai; Padrah, Shahrokh; Strømgaard, Kristian

    2014-01-01

    An effective and improved procedure is developed for the synthesis of α-hydroxy carboxylic acids by treatment of the corresponding protonated α-amino acid with tert-butyl nitrite in 1,4-dioxane-water. The amino moiety must be protonated and located α to a carboxylic acid function in order to...... undergo initial diazotization and successive hydroxylation, since neither β-amino acids nor acid derivatives such as esters and amides undergo hydroxylations. The method is successfully applied for the synthesis of 18 proteinogenic amino acids. © 2014 Elsevier Ltd. All rights reserved....

  9. A new ether-based electrolyte for dendrite-free lithium-metal based rechargeable batteries

    Rongrong Miao; Jun Yang; Zhixin Xu; Jiulin Wang; Yanna Nuli; Limin Sun

    2016-01-01

    A new ether-based electrolyte to match lithium metal electrode is prepared by introducing 1, 4-dioxane as co-solvent into lithium bis(fluorosulfonyl)imide/1,2-dimethoxyethane solution. Under the synergetic effect of solvents and salt, this simple liquid electrolyte presents stable Li cycling with dendrite-free Li deposition even at relatively high current rate, high coulombic efficiency of ca. 98%, and good anodic stability up to ~4.87 V vs Li RE. Its excellent performance will open up a new ...

  10. Dielectric relaxation studies of methyl cellulose with phenol derivatives in non-polar solvents using time domain reflectometry

    Dielectric relaxation measurements of methyl cellulose with substituted phenols p-cresol, m-cresol and o-cresol mixture in different non-polar solvents CCl4, benzene and 1,4-dioxan for different concentrations over the frequency range of 10 MHz-20 GHz at 303 K have been carried out using Time Domain Reflectometry (TDR). Dielectric parameters such as static permittivity (ε0) and relaxation time (τ) were determined and discussed to yield information on the molecular structure and dynamics of the mixture. The dielectric constant and relaxation time were found to be high for methyl cellulose with p-cresol in CCl4 compared with the other mixtures.

  11. SYNTHESIS OF NOVEL HYDROPHILIC BIODEGRADABLE POLYESTER WITH FUNCTIONALIZED SIDE CHAIN GROUPS

    Ji-yuan Yang; Jian Yu; Huai-zhong Pan; Zhong-wei Gu; Wei-xiao Caoa; Xin-de Feng

    2001-01-01

    A substituted glycolide, 3-benzyloxymethyl-1,4-dioxane-2,5-dione, was synthesized. It is a suitable precursor for the preparation of a new hydrophilic biodegradable poly(a-hydroxy acid). The polymerizations were carried out in bulk in the presence of Sn(Oct)2 at 120-140℃. The resulting polymers were subjected to hydrogenolysis with a Pd/C catalyst in a mixed solvent to remove the protecting benzyl groups. A novel poly(a-hydroxy acid) with pendant hydroxy groups was obtained. The hydrophilicity of the resulting polymer was evaluated preliminarily.``

  12. Studies on Excess Volume, Viscosity, and Speed of Sound of Binary Mixtures of Methyl Benzoate in Ethers at T=(303.15,308.15, and 313.15) K

    Rathnam, M. V.; Ambavadekar, Devappa R.; Nandini, M.

    2013-01-01

    Densities, viscosities, and speed of sound have been determined at T = (303.15, 308.15, and 313.15) K for the binary mixtures of methyl benzoate with tetrahydrofuran, 1,4-dioxane, anisole, and butyl vinyl ether over the entire range of composition. Using these measured values, excess volume VE, deviation in viscosities Δη, excess Gibb’s free energy of activation for viscous flow ΔG*E, and deviation in isentropic compressibility Δks have been calculated. These calculated binary data have been...

  13. Recent progress in electron scattering from atoms and molecules

    Brunger, M. J. [Centre for Antimatter-Matter Studies, CAPS, Flinders University, GPO Box 2100, Adelaide, SA 5001, Australia and Institute of Mathematical Sciences, University of Malaya, Kuala Lumpur (Malaysia); Buckman, S. J. [Institute of Mathematical Sciences, University of Malaya, Kuala Lumpur, Malaysia and Centre for Antimatter-Matter Studies, AMPL, Australian National University, Canberra, ACT 0200 (Australia); Sullivan, J. P.; Palihawadana, P. [Centre for Antimatter-Matter Studies, AMPL, Australian National University, Canberra, ACT 0200 (Australia); Jones, D. B. [School of Chemical and Physical Sciences, Flinders University, GPO Box 2100, Adelaide, SA 5001 (Australia); Chiari, L.; Pettifer, Z. [Centre for Antimatter-Matter Studies, CAPS, Flinders University, GPO Box 2100, Adelaide, SA 5001 (Australia); Silva, G. B. da [Centre for Antimatter-Matter Studies, CAPS, Flinders University, GPO Box 2100, Adelaide, SA 5001, Australia and Universidade Federal de Mato Grosso, Barra do Garças, Mato Grosso (Brazil); Lopes, M. C. A. [Centre for Antimatter-Matter Studies, CAPS, Flinders University, GPO Box 2100, Adelaide, SA 5001, Australia and Departamento de Fisica, Universidade Federal de Juiz de Fora, Juiz de Fora, MG (Brazil); Duque, H. V. [Departamento de Fisica, Universidade Federal de Juiz de Fora, Juiz de Fora, MG (Brazil); Masin, Z.; Gorfinkiel, J. D. [Department of Physical Sciences, The Open University, Walton Hall, Milton Keynes, MK7 6AA (United Kingdom); Garcia, G. [Instituto de Fisica Fundamental, CSIC, Madrid E-28006 (Spain); Hoshino, M.; Tanaka, H. [Department of Physics, Sophia University, Tokyo, 102-8554 (Japan); Limão-Vieira, P. [Laboratório de Colisões Atómicas e Moleculares, CEFITEC, Universidade Nova de Lisboa, 2829-516 Caparica (Portugal)

    2014-03-05

    We present and discuss recent results, both experimental and theoretical (where possible), for electron impact excitation of the 3s[3/2 ]{sub 1} and 3s′[1/2 ]{sub 1} electronic states in neon, elastic electron scattering from the structurally similar molecules benzene, pyrazine, and 1,4-dioxane and excitation of the electronic states of the important bio-molecule analogue α-tetrahydrofurfuryl alcohol. While comparison between theoretical and experimental results suggests that benchmarked cross sections for electron scattering from atoms is feasible in the near-term, significant further theoretical development for electron-molecule collisions, particularly in respect to discrete excitation processes, is still required.

  14. Reactivity of unsymmetrically substituted natural porphyrins with copper (2), zinc (2) and cadmium (2) nitrates in oxygen-containing organic solvents

    Complex formation of mesoporphyrin, pyroporphyrin and rhodoporphyrin with copper(2), zinc(2) and cadmium(2) nitrates in acetone, 1.4-dioxane and ethyl acetate at a temperature of 295-318 K was studied. The data obtained were used for estimating constant rates, activation energy and entropy of reaction. By transfer from acetone to dioxane and ethylacetate complex formation rate was decreasing by one-two orders independently of metal cation nature. Solventleveling effect on complex formation is attributed to steric properties of solvate shell of salts

  15. Synthesis and click chemistry of a new class of biodegradable polylactide towards tunable thermo-responsive biomaterials†

    Zhang, Quanxuan; Ren, Hong; Baker, Gregory L.

    2015-01-01

    A new class of clickable and biodegradable polylactide was designed and prepared via bulk polymerization of 3,6-dipropargyloxymethyl-1,4-dioxane-2,5-dione (1) which was synthesized from easily accessible propargyloxylactic acid (5). A homopolymer of 1 and random copolymer of 1 with l-lactide were obtained as amorphous materials and exhibit low Tg of 8.5 and 34 °C, respectively, indicating their promising potentials for biomedical applications. The statistical nature of random copolymers was i...

  16. A new ether-based electrolyte for dendrite-free lithium-metal based rechargeable batteries

    Miao, Rongrong; Yang, Jun; Xu, Zhixin; Wang, Jiulin; Nuli, Yanna; Sun, Limin

    2016-02-01

    A new ether-based electrolyte to match lithium metal electrode is prepared by introducing 1, 4-dioxane as co-solvent into lithium bis(fluorosulfonyl)imide/1,2-dimethoxyethane solution. Under the synergetic effect of solvents and salt, this simple liquid electrolyte presents stable Li cycling with dendrite-free Li deposition even at relatively high current rate, high coulombic efficiency of ca. 98%, and good anodic stability up to ~4.87 V vs Li RE. Its excellent performance will open up a new possibility for high energy-density rechargeable Li metal battery system.

  17. Fabrication and characterization of modified nanofibrous poly(L-lactic acid) scaffolds by thermally induced phase separation technique and aminolysis for promoting cyctocompatibility.

    Chen, Shunyu; He, Zhihang; Xu, Guojie; Xiao, Xiufeng

    2016-07-01

    Modified nanofibrous Poly(L-lactic acid) (PLLA) scaffolds were fabricated by aminolysis combined with thermally induced phase separation technique using PLLA/1,4-dioxane/urea-NaOH-H2O system at -40 °C freeze temperature. Aminolysis led to the modification of scaffold resulting in enhancement in the bioactivity. The surface of the modified nanofibrous scaffold provided a good environment for attachment and proliferation of MC3T3-E1 subclone 14 cells, exhibiting significant potential for bone tissue regeneration and for promoting cytocompatibility. PMID:27095503

  18. Removal of micro-pollutants from drinking water with advanced oxidation processes

    Sander, Fabian

    2009-01-01

    This thesis determines the feasibility of ozone gas and ultraviolet (UV)technologies to reduce pollutants from drinking water. The merging of both techniques, ozone and UV, is known as a so called advanced oxidation process (AOP). ITT Wedeco is developing new technologies to meet the growing concern of water works to remove micro-pollutants from their water. The emphasis of this work was put on the formation of the oxidation by-product bromate and the removal of the solvent 1.4 dioxane fr...

  19. Electrochemical behaviour and application of a cadmium-selective electrode in mixed solvents

    A study was made on performance characteristics of solid membrane cadmium-selective electrode in organic-water media, containing 10-90 vol.% dimethylsulfoxide, dimethylformamide (DMFA), ethanol, 1,4-dioxane and acetonitrile. It was established that linearity range of electrode ion function, detection limit of Cd(2) ions and the time of electrode response differed, depending on Cd(2) concentration in different media. In media, containing 50-75% of ethanol or DMFA the detection limit for Cd(2) decreases by one order as compared to aqueous solutions

  20. Comparison of UVC/S2O8 2- with UVC/H2O2 in terms of efficiency and cost for the removal of micropollutants from groundwater

    Antoniou, Maria; Andersen, Henrik Rasmus

    2015-01-01

    This study compared the UVC/S2O8(2-) system with the more commonly used AOP in water industry, UVC/H2O2, and examined whether the first one can be an economically feasible alternative technology. Atrazine and 4 volatile compounds (methyl tert-butyl ether, cis-dichlorethen, 1,4-dioxane and 1,1,1-trichloroethane) were chosen as model contaminants because they exhibit different susceptibility to UVC photolysis and AOPs. A collimated beam apparatus was utilized for the majority of the experiments...

  1. Preparation of porous poly(L-lactic acid) honeycomb monolith structure by phase separation and unidirectional freezing.

    Kim, Jin-Woong; Taki, Kentaro; Nagamine, Shinsuke; Ohshima, Masahiro

    2009-05-01

    A honeycomb monolith structure with micro/nanoscale porous walls was successfully fabricated in poly(l-lactic acid) (PLLA) by integrating polymer-solvent and polymer-polymer phase separations induced during a pseudosteady-state unidirectional freezing process. Poly(ethylene glycol) (PEG) and PLLA were dissolved in 1,4-dioxane to prepare a single phase polymer solution. The direction of freezing created a honeycomb monolith structure of PLLA/PEG polymers. Crystallization of the solvent reduced the solvent concentration and induced liquid-liquid phase separation during the unidirectional freezing. A sea-and-island morphology, where PEG domains were dispersed in the PLLA matrix, was developed, and pores were created in the channel walls of the honeycomb monolith structure by leaching out the PEG domain. The effects of the PEG molecular weight and the PLLA/PEG weight ratio on the aligned honeycomb structure and the pores in the channel walls were investigated. A ternary phase diagram for PLLA, PEG, and 1,4-dioxane was created from cloud point temperature measurements. Based on this phase diagram, hypotheses for the mechanism of the cellular-dendritic transition and the formation mechanism of the pores in the channel walls are proposed. PMID:19290649

  2. Recovery of Uranium (Vi) From Treated Technological Sample, El Sela Area, South Eastern Desert, Egypt

    The extraction of uranium from aqueous nitrate solution was studied using the organic extractant tributyl phosphate or 1,4 Dioxane dissolved in different diluents. The parameters affecting the extraction and stripping of U (Vi) include types of diluents, extractants concentrations, aqueous to organic phase ratio (A/O), shaking time and stripping agents. The factors studied were followed by application of the suitable extraction system to extract U content from two fractions of the solid waste (slime and coarse size) from El Sela area, Egypt. The data obtained showed that, best results were obtained using each of the following systems; 20 % TBP dissolved in toluene, A/O 1:1, 4 min. of shaking time and 5 M HNO3 acid stripping solution, or; 5 % 1,4 Dioxane dissolved in CCl4, A/O 1:1, 5 min. of shaking time and 0.5 M HNO3 acid for the stripping process. It was recommended to wash the slime sample by acidified water to decrease the range of ph to 1 to overcome the problem of hydrolysis and precipitation of uranium. The data obtained from statistical calculations showed that, Error (%) in studied samples is less than 2 %. While, the accuracy (Δ) is less than ±3 declaring high accuracy and precision for the obtained results.

  3. Synthesis and antibacterial activity of some Schiff base complexes

    R. NAIR

    2006-07-01

    Full Text Available Two Schiff bases were synthesized from raceacetophenone: 1 ADS1: 4-ethyl-6-{(E-1-[(3-nitrophenylimino]ethyl}benzene-1,3-diol and 2 ADS3: 4-ethyl-6-{(E-1-[(2-nitrophenylimino]ethyl}benzene-1,3-diol. Then their metal complexes were formed. The metals selected for the preparation of complexes were copper, nickel, iron and zinc. Hence, in total 8 metal complexes were synthesized and screened for antibacterial activity against some clinically important bacteria, such as Pseudomonas aeruginosa, Proteus vulgaris, Proteus mirabilis, Klebsiella pneumoniae and Staphylococcus aureus. The in vitro antibacterial activity was determined by the Agar Ditch technique using DMF (polar and 1,4-dioxane (non polar as solvents. The Schiff bases showed greater activity than theirmetal complexes; themetal complexes showed differential effects on the bacterial strains investigated and the solvent used, suggesting that the antibacterial activity is dependent on the molecular structure of the compound, the solvent used and the bacterial strain under consideration. The Schiff base ADS3 in the polar solvent DMF showed better antibacterial activity towards the investigated bacterial strains. Amongst the four metals, Zn showed the best antibacterial activity followed by Fe in 1,4-dioxane while Ni followed by Zn and Fe showed the best antibacterial activity in DMF. P. vulgaris was the most resistant bacteria.

  4. Synthesis and antibacterial activity of some Schiff bases derived from 4-aminobenzoic acid

    JIGNA PAREKH

    2005-10-01

    Full Text Available The following Schiff bases have been synthesized: (1 4-[(2-chlorobenzylidene amino]benzoic acid [JP1], (2 4-[(furan-2-ylmethyleneamino]benzoic acid [JP2], (3 4-[(3-phenylallylideneamino]benzoic acid [JP3], (4 4-[(2-hydroxybenzylidene amino]benzoic acid [JP4], (5 4-[(4-hydroxy-3-methoxybenzylideneamino]benzoic acid [JP5] and (6 4-[(3-nitrobenzylideneamino]benzoic acid [JP6]. They were screened as potential antibacterial agents against a number of medically important bacterial strains. The antibacterial activity was studied against A. faecalis ATCC 8750, E. aerogenes ATCC 13048, E. coli ATCC 25922, K. pneumoniae NCIM 2719, S. aureus ATCC 25923, P. vulgaris NCIM 8313, P. aeruginosa ATCC 27853 and S. typhimurium ATCC 23564. The antibacterial activity was evaluated using the Agar Ditch method. The solvents used were 1,4-dioxane and dimethyl sulfoxide. Different effects of the compounds were found in the bacterial strains investigated and the solvents used, suggesting, once again, that the antibacterial activity is dependent on the molecular structure of the compound, the solvent used and the bacterial strain under consideration. In the present work, 1,4-dioxane proved to be a good solvent in inhibiting the above stated bacterial strains.

  5. Optimized and Validated Spectrophotometric Methods for the Determination of Enalapril Maleate in Commercial Dosage Forms

    Sk Manirul Haque

    2008-01-01

    Full Text Available Four simple, rapid and sensitive spectrophotometric methods have been proposed for the determination of enalapril maleate in pharmaceutical formulations. The first method is based on the reaction of carboxylic acid group of enalapril maleate with a mixture of potassium iodate (KIO3 and iodide (KI to form yellow colored product in aqueous medium at 25 ± 1°C .The reaction is followed spectrophotometrically by measuring the absorbance at 352 nm. The second, third and fourth methods are based on the charge transfer complexation reaction of the drug with p-chloranilic acid (pCA in 1, 4-dioxan-methanol medium, 2, 3-dichloro 5, 6-dicyano 1, 4-benzoquinone (DDQ in acetonitrile-1,4 dioxane medium and iodine in acetonitrile-dichloromethane medium. Under optimized experimental conditions, Beer’s law is obeyed in the concentration ranges of 2.5–50, 20–560, 5–75 and 10–200 μg mL−1, respectively. All the methods have been applied to the determination of enalapril maleate in pharmaceutical dosage forms. Results of analysis are validated statistically.

  6. Solvent selection causes remarkable shifts of the ``Ouzo region'' for poly(lactide-co-glycolide) nanoparticles prepared by nanoprecipitation

    Beck-Broichsitter, Moritz; Nicolas, Julien; Couvreur, Patrick

    2015-05-01

    Polymer nanoparticles (NPs) offer versatile novel biological features of interest for drug delivery applications. ``Ouzo diagrams'' allowed for a systematic manufacture of specified colloidal formulations by the widely used nanoprecipitation process. Surprisingly, despite the well-documented relevance of the applied organic solvent for nanoprecipitation, its effect on the actual status of the ``Ouzo region'' was so far not studied. Herein, investigations were undertaken to account for the potential impact of the solvent type on the ``Ouzo diagrams'' for poly(lactide-co-glycolide) (PLGA) and tetrahydrofuran (THF), 1,4-dioxane, acetone and dimethyl sulfoxide (DMSO). The ``Ouzo region'' shifted considerably to higher polymer fractions upon solvent change (rank order: THF documented relevance of the applied organic solvent for nanoprecipitation, its effect on the actual status of the ``Ouzo region'' was so far not studied. Herein, investigations were undertaken to account for the potential impact of the solvent type on the ``Ouzo diagrams'' for poly(lactide-co-glycolide) (PLGA) and tetrahydrofuran (THF), 1,4-dioxane, acetone and dimethyl sulfoxide (DMSO). The ``Ouzo region'' shifted considerably to higher polymer fractions upon solvent change (rank order: THF Electronic supplementary information (ESI) available. See DOI: 10.1039/c5nr01695a

  7. 纤维素酶催化与三液相萃取偶联制备盾叶薯蓣皂苷元%Preparation of diosgenin by integrated bioprocess of cellulase catalysis and extration in three-liquid-phase system

    魏夺; 董悦生; 韩松; 修志龙

    2012-01-01

    Using coupling biotech of cellulase-catalysis and extrusion in three-liquid-phase system that composed of n-hexane, 1,4-dioxane and ammonium sulfate to hydrolyze dioscin in Chinese yan and glucose connected to steroidal saponins, and extration separation to collect diosgenin. The distribution of several steroidal saponins, hydrolyzed glucose, enzyme and its activity in the three-phase system were studied, and catalytic conversion by cellulase-enzyme and formation of diosgenin in three-liquid, organic and aqueous phases were compared. The results showed that diosgenin yield in the three-liquid-phase system could compare with that in organic phase and aqueous phase. The three-liquid-phase system could be suitable for simultaneous enzymatic hydrolysis of steroidal saponins and extration of diosgenin and glucose. The substrate and enzyme were held in the middle phase of 1,4-dioxane, whiles the products, diosgenin and glucose, were partitioned into the top and bottom phase, respectively. The yields of diosgenin was 69. 4% at 96 h in the three-liquid-phase system, which was twice and 27. 6 folds obtained in organic phase and aqueous phase respectively.

  8. Experimental Results on Electrorheology of Liquid Crystalline Polymer Solutions

    Neves, S.; Leal, C. R.; Cidade, M. T.

    2008-07-01

    The electrorheological (ER) effect is known as the enhancement of the apparent viscosity upon application of an external electric field. Suspensions of polarizable particles in non-conducting solvents are the most studied electrorheological fluids, however, liquid crystalline materials may also present ER effect as long as their dielectric anisotropy is positive. In the liquid crystalline state of a positive dielectric anisotropy, the application of the electric field makes the director align perpendicular to the flow direction, thus increasing the apparent viscosity. In this work results of two liquid crystalline polymer solutions, acetoxypropylcellulose (APC) in dimethylacetamide (DMAc) and poly-γ-benzyl-L-glutamate (PBLG) in 1,4-dioxane, presenting opposite behavior upon application of the electric field, will be presented. APC/DMAc (negative dielectric anisotropy) presents a decrease of the apparent viscosity upon application of the electric field, as expected, while PBLG/1,4-dioxane (positive dielectric anisotropy) presents the opposite behavior. For this last solution we will present the shear flow curves for different electric fields in function of polymer molecular weight and solution concentration.

  9. Microscopic observation of ordered colloids in sedimentation equilibrium and important role of Debye-screening length. VI. Organic solvent aqueous mixtures for heavy and monodisperse spheres (specific gravity=1.50)

    Okubo, Tsuneo

    1988-02-01

    A metallurgical microscope is used to directly observe the ordered structures of heavy and monodisperse polystyrene-type spheres (specific gravity=1.50) in sedimentation equilibrium and in organic solvent aqueous mixtures. Eight kinds of water miscible organic solvents, i.e., methanol, ethanol, propanol, 1,4-dioxane, ethylene glycol, propylene glycol, N-methylformamide (NMF), and N-methylacetamide (NMA) are used. The center-to-center interparticle distances (D) in the hexagonal ordering increase by the addition of organic solvents of dielectric constants lower than that of water, whereas D decreases in the presence of NMF or NMA, which has a dielectric constant higher than that of water. Young's modulus for the ordered lattices is estimated to be from 0.44 to 1.5 Pa in methanol (0 to 30 vol %) aqueous mixtures. These results show that electrostatic interparticle repulsion and the elongated Debye-screening length around the spheres are essential for the ordering.

  10. Dielectric Relaxation Study of Some Solutions Containing β-Cyclodextrin and Dimethylsulfoxide

    Betting, H.; Stockhausen, M.

    1999-07-01

    Dielectric spectra have been measured up to 72 GHz at 20°C for solutions of β-cyclodextrin (CD) in the following solvents over the whole solubility range of CD: dimethylsulfoxide (DMSO), DMSO/ 1,4-dioxane mixture (2:1 molar ratio), DMSO/water mixtures (2:1 and 1:2). The spectra are analyzed into a sum of Debye type spectral components. These are likely to be caused by different physical pro-cesses. The discussion shows (i) that there is a preferential CD-DMSO interaction, by far exceeding the CD-water interaction, and (») that, concerning CD-DMSO, a loose interaction can be distinguished from the formation of an inclusion complex.

  11. Antibacterial and preliminary phytochemical and physico-chemical analysis of Eucalyptus citriodora Hk leaf.

    Vaghasiya, Y; Nair, R; Chanda, S

    2008-06-15

    The present communication deals with some studies on the antibacterial, physico-chemical and phytochemical parameters of different extracts of Eucalyptus citriodora leaf. The antibacterial study was performed using the agar ditch method on some clinically important bacteria, namely Pseudomonas pseudoalcaligenes, Proteus vulgaris, Citrobacter freundii, Staphylococcus subflava, Bacillus megaterium, and Enterobacter aerogenes. Physico-chemical parameters namely water, methanol, 1,4-dioxane, DMF, acetone soluble extractives, total ash, melting point, and pH were determined according to pharmacopoeial procedures. Methanol gave the maximum extract while it was minimum in water. Phytochemical parameters were screened for alkaloids, tannins, cardiac glycosides, saponins, steroids and flavonoids. Tannins and flavonoids gave positive results, while steroids and glycosides were absent. The most susceptible bacteria was C. freundii, while the most resistant was P. vulgaris. PMID:18569717

  12. PDMS/glass microfluidic cell culture system for cytotoxicity tests and cells passage

    Ziolkowska, K.; Jedrych, E.; Kwapiszewski, R.; Lopacinska, Joanna M.; Skolimowski, Maciej; Chudy, M.

    2010-01-01

    In this paper, hybrid (PDMS/glass) microfluidic cell culture system (MCCS) integrated with the concentration gradient generator (CGG) is presented. PDMS gas permeability enabled cells' respiration in the fabricated microdevices and excellent glass hydrophilicity allowed successful cells' seeding....... The human lung carcinoma cells (A549) were cultured in the microdevice for several days. The growth and proliferation of cells was monitored using an inverted fluorescence microscope. After the cells' confluence was achieved in the microchambers, the novel method of cells' passaging in the designed...... microdevice was developed and successfully tested. The MCCS microdevice is fully reusable, i.e. it can be used several times for various cell culture and cytotoxic experiments. The suitability of designed MCCS for cell-based cytotoxicity assay application was verified using 1,4-dioxane as a model toxic agent...

  13. A Tin Analogue of Carbenoid: Isolation and Reactivity of a Lithium Bis(imidazolin-2-imino)stannylenoid.

    Ochiai, Tatsumi; Franz, Daniel; Wu, Xiao-Nan; Irran, Elisabeth; Inoue, Shigeyoshi

    2016-06-01

    The lithium bis(imino)stannylenoid (NIPr)2 Sn(Li)Cl (1; NIPr=bis(2,6-diisopropylphenyl)imidazolin-2-imino) was prepared by the reaction of LiNIPr with 0.5 equiv of SnCl2 ⋅diox (diox=1,4-dioxane) and the ambiphilic character of the compound was demonstrated by investigations into its reactivity. Treatment of 1 with I2 or MeI yielded the oxidative addition products (NIPr)2 SnI2 and (NIPr)2 Sn(Me)I, respectively. In contrast, the reaction of 1 with one equivalent of Me3 SiCl resulted in the formation of Me3 SiNIPr and the chlorostannylene dimer [NIPrSnCl]2 . Moreover, the substitution reaction of compound 1 with MeLi led to the formation of the methyl-substituted stannate (NIPr)2 Sn(Li)Me. PMID:27100133

  14. Gold(I-catalyzed hydroarylation reaction of aryl (3-iodoprop-2-yn-1-yl ethers: synthesis of 3-iodo-2H-chromene derivatives

    Pablo Morán-Poladura

    2013-10-01

    Full Text Available An efficient entry to the preparation of elusive 4-unsubstituted-3-iodo-2H-chromenes has been accomplished as result of a catalytic cyclization. Thus, upon exposition of [(3-iodoprop-2-yn-1-yloxy]arenes to IPrAuNTf2 (3 mol %, in 1,4-dioxane at 100 °C, the desired heterocyclic motif is readily assembled. This process nicely tolerates a variety of functional groups and, interestingly, it is compatible with the presence of strong electron-withdrawing groups attached to the arene. The overall transformation can be termed as a new example of a migratory cycloisomerization and, formally, it involves well-blended 1,2-iodine shift and hydroarylation steps.

  15. Efecto de solvente sobre la descomposición térmica de trans-3,6-dimetil-3,6-difenil-1,2,4,5-tetraoxaciclohexano en solución

    Eyler Gladys N.

    2004-01-01

    Full Text Available The thermal decomposition reaction of trans-3,6-dimethyl-3,6-diphenyl-1,2,4,5-tetraoxacyclohexane (acetophenone cyclic diperoxide, DPAF, in different solvents (methanol, 1,4-dioxane, acetonitrile and 2-propanol/benzene mixtures in the initial concentration and temperature ranges of (4.2-10.5 x 10-3 M and 140.0 to 185.0 ºC, respectively, follows a pseudo first order kinetic law up to at least 70% DPAF conversion. An important solvent effect on the rate constant values, activation parameters (DH# and DS# and reaction products obtained in different solvents is detected, showing that the reaction is accelerated in alcohols.

  16. Selective hydrogenation of maleic anhydride over Pd/Al2O3 catalysts prepared via colloid deposition

    Hongjing Yuan; Chunlei Zhang; Weitao Huo; Chunli Ning; Yong Tang; Yi Zhang; Dequan Cong; Wenxiang Zhang; Jiahuan Luo; Su Li; Zhenlu Wang

    2014-01-01

    Pd/Al2O3 catalysts were prepared via colloid deposition and the performance of the catalysts was examined in the selective hydrogenation of maleic anhydride to succinic anhydride. When the reaction was carried on in a batch system with 1,4-dioxane as the solvent (353K and 1.0MPa), high conversion of maleic anhydride (>98%) and high selectivity (>99%) for succinic anhydride were observed after 5 h. The as-prepared Pd/Al2O3 catalyst also showed excellent performance in solvent-free system and fixed-bed systems. The maleic anhydride (MA) conversion was greater than 98%, and high selectivity (>99%) for succinic anhydride was obtained after 1600 h in a fixed bed reacter. The results showed that the activity of the Pd/Al2O3 catalysts was excellent due to its high active surface area.

  17. Hydrolysis of 4-Acetoxystyrene Polymers Prepared by Atom Transfer Radical Polymerization

    Chen, Xianyi; Jankova, Katja; Kops, Jørgen;

    1999-01-01

    Hydrolysis of 4-acetoxystyrene polymers prepared by atom transfer radical polymerization was carried out under various reaction conditions. It was found that hydrazinolysis of 4-acetoxystyrene homopolymers, random and block copolymers with styrene in 1,4-dioxane, afforded the corresponding narrow...... dispersed materials with phenolic groups which were substantially free from crosslinkages. Gel permeation chromatographic (GPC) analysis of these polymers revealed different extents of molecular weight distribution (MWD) broadening for the hydrolysis products for the different structures. On the other hand......, by NaOH catalyzed deprotection, the 4-acetoxystyrene polymers including triblock copolymer poly(4-acetoxystyrene-b-isobutylene-b-4-toxystyrene) suffered from some degrees of coupling or even gelation, except for poly(styrene-b-4-acetoxystyrene-b-styrene) which also by this method could be...

  18. Total lipid production of the green alga Nannochloropsis sp. QII under different nitrogen regimes

    The green alga Nannochloropsis sp. QII was cultivated in media with sufficient and growth-limiting levels of nitrogen (nitrate). Nitrogen deficiency promoted lipid synthesis yielding cells with lipids comprising 55% of the biomass. The major lipids were triacylglycerols (79%), polar lipids (9%) and hydrocarbons (2.5%). The polar lipids consisted of a broad range of phospholipids, glycolipids and sulfolipids. Other lipids identified were pigments, free fatty acids, saponifiable and unsaponifiable sterol derivatives, various glycerides, a family of alkyl-1, 4-dioxane derivatives and a series of alkyl- and hydroxy-alkyl-dimethyl-acetals. Experiments in which 14CO2 was provided at different times in the growth cycle demonstrated that enhanced lipid biosynthesis at low nitrogen levels resulted principally from de novo CO2 fixation

  19. Characteristic occurrence patterns of micropollutants and their removal efficiencies in industrial wastewater treatment plants.

    Lee, In-Seok; Sim, Won-Jin; Kim, Chang-Won; Chang, Yoon-Seok; Oh, Jeong-Eun

    2011-02-01

    The concentrations and removal efficiencies of various kinds of micropollutants were investigated and the relationships between the input sources of industrial wastewater and occurrence patterns of each micropollutant were identified at nine on-site industrial wastewater treatment plants (WWTPs). The distribution pattern of each compound varied according to the WWTP type and several micropollutants were significantly related with specific industries: chlorinated phenols (ClPhs) with paper and metal industries, polycyclic aromatic hydrocarbons (PAHs) with petrogenic- and pyrogenic-related industries, polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) with the paper industry, and chlorinated benzenes (ClBzs) with dye-related industries. The activated sludge (AS) process was very efficient in the removal of ClPhs and PAHs, and the filtration process in the removal of PCDD/Fs and 1,4-dioxane. Generally, the removal efficiencies of each micropollutant varied according to the WWTP type. PMID:21140016

  20. Studies of linear correlation factor of dielectric polarization and excess dipolar free energies of amides in apolar solvents

    M Malathi; R Sabesan; S Krishnan

    2005-09-01

    The Kirkwood–Frohlich correlation factor (), Eyring's parameters and * and the dipolar excess free energies of dilute solutions of formamide, acetamide, -methyl acetamide, , -dimethyl formamide and , -dimethyl acetamide in 1,4-dioxan/benzene were obtained from a measurement of their static dielectric permittivities at 308 K. The fluid structure of these amides is discussed. Both in formamide and acetamide a dimeric linear chain with the individual dipoles more or less parallely oriented is preferred. In -methyl acetamide, the antiparallel orientation of dipoles at lower concentrations turns into a parallel orientation with increase of concentration. In tertiary amides, with increase of concentration, parallel orientation of dipoles with global value of tending to unity is observed. The dipolar excess free energy of mixing in a given solvent is of the order primary amide > secondary amide > tertiary amide.

  1. 利用二元体系的C-H红外光谱推算汽液平衡数据%Prediction of Vapor-Liquid Equilibrium Data from C-H Band Shift of IR Spectra in Some Binary Systems

    朱霄; 姚加; 李浩然; 韩世钧

    2007-01-01

    Prediction of vapor-liquid equilibrium (VLE) is extremely necessary to separate liquid mixture in chemical production, especially when the required experimental data are difficult to measure, or the measurement is not economical. The infinite dilution activities can be used to predict VLE. However, it needs both thc ends of the activities that are difficult to obtain for many systems. In the present study, a new model is proposed for correlating the frequency shift of C-H stretching band of IR spectra over the whole concentration. Investigated mixtures include water/2-propanol, water/N, N-dimethylformamide (DMF), water/methanol, water/ethanol, water/1, 4-dioxane,and water/dimethylsulfoxidc (DMSO) systems. Simultaneous correlations of C-H frequency shift and VLE data arc made. Furthermore, the VLE data were predicted with satisfactory results by the parameters obtained from IR spectra coupled with one of the infinite dilution activity coefficients.

  2. Optimised conditions for the synthesis of (17)O and (18)O labelled cholesterol.

    de la Calle Arregui, Celia; Purdie, Jonathan A; Haslam, Catherine A; Law, Robert V; Sanderson, John M

    2016-02-01

    Conditions are described for the preparation of cholesterol with (17)O and (18)O labels from i-cholesteryl methyl ether using minimal amounts of isotopically enriched water. Optimum yields employed trifluoromethanesulfonic acid as catalyst in 1,4-dioxane at room temperature with 5 equivalents of water. An isotopic enrichment >90% of that of the water used for the reaction could be attained. Tetrafluoroboric acid could also be used as catalyst, at the expense of a lower overall reaction yield. Byproducts from the reaction included dicholesteryl ether, methyl cholesteryl ether, compounds formed by ether hydrolysis, and olefins arising from elimination reactions. Reactions in tetrahydrofuran yielded significant amounts of cholesteryl ethers formed by reaction with alcohols arising from hydrolysis of the solvent. PMID:26724708

  3. Studies on Excess Volume, Viscosity, and Speed of Sound of Binary Mixtures of Methyl Benzoate in Ethers at T=(303.15,308.15, and 313.15 K

    M. V. Rathnam

    2013-01-01

    Full Text Available Densities, viscosities, and speed of sound have been determined at T = (303.15, 308.15, and 313.15 K for the binary mixtures of methyl benzoate with tetrahydrofuran, 1,4-dioxane, anisole, and butyl vinyl ether over the entire range of composition. Using these measured values, excess volume VE, deviation in viscosities Δη, excess Gibb’s free energy of activation for viscous flow ΔG*E, and deviation in isentropic compressibility Δks have been calculated. These calculated binary data have been fitted to Redlich-Kister equation to determine the appropriate coefficients. The values of excess volume VE and deviation in viscosities Δη are negative over the entire range of composition for all the binary systems at the studied temperatures. The behavior of these parameters with composition of the mixture has been discussed in terms of molecular interactions between the components of liquids.

  4. Henry’s constants and activity coefficients of some organic solutes in 1-butyl,3-methylimidazolium hydrogen sulfate and in 1-methyl,3-trimethylsilylmethylimidazolium chloride

    Highlights: ► New solubility data are reported for two ionic liquids. ► Density data are reported. ► Thermo-gravimetric analysis data are obtained. - Abstract: Using a customized capillary gas–liquid chromatography column, Henry’s constants and activity coefficients at infinite dilution are reported for benzene, toluene, ethyl acetate, 1,4-dioxane, 1,2-dimethoxyethane, acetonitrile, nitromethane, tetrahydrofuran, chloroform, methanol, ethanol, and 1-propanol in ionic liquids 1-butyl,3-methylimidazolium hydrogen sulfate [BMIM][HSO4] and 1-methyl,3-trimethylsilylmethylimidazolium [SiMIM][Cl] chloride from 313 to 413 K. These acidic ionic liquids may provide suitable media for acid-catalyzed chemical reactions.

  5. Control of pore size in L-lactide/epsilon-caprolactone copolymer foams for tissue regeneration by the freeze-drying method.

    Nakao, Hiroyuki; Hyon, Suong-Hyu; Tsutsumi, Sadami; Matsumoto, Takuya; Takahashi, Junzo

    2003-09-01

    In the regeneration and repair of missing tissues, synthetic polymer scaffolds need many pores to involve cells and to supply cells with nutrients. The control of the pore size of biodegradable L-lactide/epsilon-caprolactone copolymer foams was studied by changing the polymer concentration and the cooling temperature in the freeze-drying method. The mixtures of polymer and 1, 4-dioxane solution were poured into an 18-8 stainless steel Petri dish and frozen. The pore size of a polymer foam tends to increase from the bottom towards the top of a Petri dish. The pore size decreased to one-half with increasing polymer concentration (1 to 10 wt%). The mean pore size in foams of 8% polymer concentration decreased from 100 microm to 20 microm as cooling temperature was lowered. This suggests that the higher cooling rate due to lower cooling temperature can produce smaller ice-crystals and result in smaller pores. PMID:14620993

  6. Calix[4]arene coated QCM sensors for detection of VOC emissions: Methylene chloride sensing studies.

    Temel, Farabi; Tabakci, Mustafa

    2016-06-01

    This paper describes the sensing studies of QCM sensors with coated some calixarene derivatives bearing different functional groups for some selected Volatile Organic Compounds (VOCs) such as acetone, acetonitrile, carbon tetrachloride, chloroform, methylene chloride (MC), N,N-dimethylformamide, 1,4-dioxane, ethanol, ethyl acetate, xylene, methanol, n-hexane and toluene. The initial experiments have revealed that whole the calix[4]arene modified QCM sensors exhibited strongest sensing ability to MC emissions. Thus, the detailed studies were performed for only MC emissions after the determination of relatively more effective calix-coated QCM sensors for MC emissions in aqueous media. The results demonstrated that QCM sensor coated with calix-7 bearing both amino and imidazole groups was most useful sensor for MC emissions with 54.1ppm of detection limit. Moreover, it was understood that cyclic structures, H-bonding capabilities and also good preorganization properties of calixarene derivatives played an important role in VOC sensing processes. PMID:27130112

  7. Heterocyclic Analogues of Xanthone and Xanthione. 1H-Pyrano[2,3-c:6,5-c]dipyrazol-4(7H-ones and Thiones: Synthesis and NMR Data

    Wolfgang Holzer

    2010-09-01

    Full Text Available The synthesis of the title compounds is described. Reaction of 1-substituted 2-pyrazolin-5-ones with 5-chloro-1-phenyl-1H-pyrazole-4-carbonyl chloride or 5-chloro-3-methyl-1-phenyl-1H-pyrazole-4-carbonyl chloride, respectively, using calcium hydroxide in refluxing 1,4-dioxane gave the corresponding 4-heteroaroylpyrazol-5-ols, which were cyclized into 1H-pyrano[2,3-c:6,5-c]dipyrazol-4(7H-ones by treatment with K2CO3/DMF. The latter were converted into the corresponding thiones upon reaction with Lawesson’s reagent. Detailed NMR spectroscopic investigations (1H, 13C, 15N of the ring systems and their precursors are presented.

  8. Palladium-catalyzed direct desulfitative C2 arylations of 3-halo-N-protected indoles using (hetero)arenesulfonyl chlorides.

    Hfaiedh, Anoir; Ben Ammar, Hamed; Soulé, Jean-François; Doucet, Henri

    2016-06-01

    The direct arylation of N-protected 3-haloindole derivatives with benzenesulfonyl chlorides as coupling partners using 5 mol% of bis(acetonitrile)dichloropalladium(ii) catalyst and lithium carbonate as a base in 1,4-dioxane was investigated. We demonstrated that both iodo and chloro substituents at the indolyl C3 position act as temporary blocking groups allowing the formation of 2-arylindoles through a direct desulfitative arylation, followed by in situ dehalogenation. While, from 3-bromoindole derivatives, 2-aryl-3-bromoindoles were obtained without debromination, and could be converted into 2,3-diarylindoles through a second palladium coupling. This method allows one to prepare in a few steps a very wide variety of indole derivatives, which are of interest in the synthesis of bioactive molecules. PMID:27171489

  9. Effect of porogenic solvent on selective performance of molecularly imprinted polymer for quercetin

    Xingliang Song

    2009-09-01

    Full Text Available Molecularly imprinted polymers (MIP's for quercetin were successfully synthesized by a thermal polymerization method using quercetin as template molecule, acrylamide as functional monomer and ethylene glycol dimethacrylate as cross-linker in the presence of four different porogenic solvents: 1,4-dioxane, tetrahydrofuran (THF, acetone, and acetonitrile. The selective performance of obtained MIP's was evaluated through HPLC analysis. The results indicated that the MIP obtained in THF showed the highest capacity and selectivity. The Scatchard method also supported HPLC results. The results were interpreted by computational quantum chemical analysis through Onsager self-consistent reaction field (SCRF technique in term of stabilization energy. It was also found that the amount of porogenic solvent used had impact on the adsorption effectiveness of MIP's.

  10. Structural and Magnetic Diversity in Alkali-Metal Manganate Chemistry: Evaluating Donor and Alkali-Metal Effects in Co-complexation Processes.

    Uzelac, Marina; Borilovic, Ivana; Amores, Marco; Cadenbach, Thomas; Kennedy, Alan R; Aromí, Guillem; Hevia, Eva

    2016-03-24

    By exploring co-complexation reactions between the manganese alkyl Mn(CH2 SiMe3 )2 and the heavier alkali-metal alkyls M(CH2 SiMe3 ) (M=Na, K) in a benzene/hexane solvent mixture and in some cases adding Lewis donors (bidentate TMEDA, 1,4-dioxane, and 1,4-diazabicyclo[2,2,2] octane (DABCO)) has produced a new family of alkali-metal tris(alkyl) manganates. The influences that the alkali metal and the donor solvent impose on the structures and magnetic properties of these ates have been assessed by a combination of X-ray, SQUID magnetization measurements, and EPR spectroscopy. These studies uncover a diverse structural chemistry ranging from discrete monomers [(TMEDA)2 MMn(CH2 SiMe3 )3 ] (M=Na, 3; M=K, 4) to dimers [{KMn(CH2 SiMe3 )3 ⋅C6 H6 }2 ] (2) and [{NaMn(CH2 SiMe3 )3 }2 (dioxane)7 ] (5); and to more complex supramolecular networks [{NaMn(CH2 SiMe3 )3 }∞ ] (1) and [{Na2 Mn2 (CH2 SiMe3 )6 (DABCO)2 }∞ ] (7)). Interestingly, the identity of the alkali metal exerts a significant effect in the reactions of 1 and 2 with 1,4-dioxane, as 1 produces coordination adduct 5, while 2 forms heteroleptic [{(dioxane)6 K2 Mn2 (CH2 SiMe3 )4 (O(CH2 )2 OCH=CH2 )2 }∞ ] (6) containing two alkoxide-vinyl anions resulting from α-metalation and ring opening of dioxane. Compounds 6 and 7, containing two spin carriers, exhibit antiferromagnetic coupling of their S=5/2 moments with varying intensity depending on the nature of the exchange pathways. PMID:26916525

  11. Aqueous foam toxicology evaluation and hazard review

    Archuleta, M.M.

    1995-10-01

    Aqueous foams are aggregates of bubbles mechanically generated by passing air or other gases through a net, screen, or other porous medium that is wetted by an aqueous solution of surface-active foaming agents (surfactants). Aqueous foams are important in modem fire-fighting technology, as well as for military uses for area denial and riot or crowd control. An aqueous foam is currently being developed and evaluated by Sandia National Laboratories (SNL) as a Less-Than-Lethal Weapon for the National Institute of Justice (NIJ). The purpose of this study is to evaluate the toxicity of the aqueous foam developed for the NIJ and to determine whether there are any significant adverse health effects associated with completely immersing individuals without protective equipment in the foam. The toxicity of the aqueous foam formulation developed for NIJ is determined by evaluating the toxicity of the individual components of the foam. The foam is made from a 2--5% solution of Steol CA-330 surfactant in water generated at expansion ratios ranging from 500:1 to 1000:1. SteoI CA-330 is a 35% ammonium laureth sulfate in water and is produced by Stepan Chemical Company and containing trace amounts (<0.1%) of 1,4-dioxane. The results of this study indicate that Steol CA-330 is a non-toxic, mildly irritating, surfactant that is used extensively in the cosmetics industry for hair care and bath products. Inhalation or dermal exposure to this material in aqueous foam is not expected to produce significant irritation or systemic toxicity to exposed individuals, even after prolonged exposure. The amount of 1,4-dioxane in the surfactant, and subsequently in the foam, is negligible and therefore, the toxicity associated with dioxane exposure is not significant. In general, immersion in similar aqueous foams has not resulted in acute, immediately life-threatening effects, or chronic, long-term, non-reversible effects following exposure.

  12. a Study of Volatile Precursors for the Growth of Cadmium Sulphide and Cadmium Selenide by Metal Organic Chemical Vapour Deposition.

    Beer, Michael P.

    Available from UMI in association with The British Library. The wide-band-gap semiconductors, cadmium sulphide and cadmium selenide, may be grown by Metal Organic Chemical Vapour Deposition (MOCVD). This method typically involves the reaction of gaseous streams of Me_2 Cd and H_2Y (Y = S, Se) over a heated substrate (usually gallium arsenide) on which the desired compound is grown as an epitaxial layer. Unfortunately, the precursors start to react in the cold zone of the reactor, that is before they reach the heated substrate. This problem is known as prereaction. The problem of prereaction is partially reduced by the use of adducts of dimethyl cadmium in place of the free dialkyl compound although the mechanism by which such adducts block prereaction is unknown. Accordingly, a study of adducts of dimethyl cadmium was undertaken with a view to determining their properties in all phases. The adduct of Me_2Cd with 2,2^ '-bipyridyl was found to be monomeric in the solid state while that with 1,4-dioxane, a volatile compound used for prereaction reduction, was found to be polymeric. A study of adducts in the gas phase using mass spectrometry and gas phase Fourier transform infrared spectroscopy gave no evidence to suggest there is any gas phase association between 1,4-dioxane and dimethyl cadmium. With the 2,2 ^'-bipyridyl adduct some evidence for partial retention of coordinate bonds upon sublimation was obtained. The solid adduct of Me _2Cd with N,N,N^' ,N^'-tetramethylethylenediamine (TMEDA) was prepared as it was hoped that the flexibility of the aliphatic Lewis base would permit the formation of an adduct containing strong co-ordinate bonds which would remain intact upon sublimation. Using gas phase electron diffraction, the structure of the adduct of Me_2Cd and TMEDA was determined. It was shown to exist in the gas phase purely as the associated monomeric species. The adduct was then employed for the growth of CdS and CdSe in an industrial MOCVD apparatus. The

  13. 木质素模型化合物香草醛Mannich反应及其产物化学结构表征%Mannich Reaction of Lignin Model Compound Vanillin and Chemical Structure Characterization of Its Product

    聂明才; 孔振武; 霍淑平; 吴国民; 陈健

    2012-01-01

    Vanillin aminated polyol(VAP) was prepared by vanillin, diethanolamine and paraformaldehyde in 1,4-dioxane by Mannich reaction. The effects of material ratio, reaction temperature, reaction time and solvent dosage on the Mannich reaction were investigated. It was observed the highest conversion rate of diethanolamine was up to 84.92 % by dropping 1,3-oxazolidine which was the reaction product of formaldehyde and diethanolamine at 60℃ for 2 h, into vanillin and reacting at 80 ℃ for 3 h in the molar ratio of n( vanillin) : n( formaldehyde) : n(diethanolamine) as 1 : 1 : 1 in 1,4-dioxane of 100 mL/mol vanillin. The chemical structure of vanillin aminated polyol was characterized by HPLC, LC-MS, FT-IR and 'H NMR, respectively.%以木质素模型化合物香草醛、二乙醇胺及多聚甲醛为原料,1,4-二氧杂环己烷为溶剂,通过Mannich反应合成了香草醛胺基多元醇,研究了物料配比、反应温度、时间及溶剂用量等因素对Mannich反应的影响.实验结果表明:反应物料按物质的量比n(香草醛):n(甲醛):n(二乙醇胺)1:1:1,甲醛与二乙醇胺60℃反应2h生成1,3-氧氮杂环戊烷,再将其滴入香草醛中,80℃反应3h,二氧六环溶剂用量为100 mL/mol(以香草醛的物质的量计),二乙醇胺的转化率最高可达到84.92%.采用HPLC、LC- MS、FT-IR及H NMR表征了香草醛胺基多元醇的化学结构,相对分子质量269.

  14. 相平衡法测定氯化聚丙烯在不同溶剂中的θ温度%Determination of Theta(θ)Temperature of Chlorinated Polypropylene in Different Solutions by Phase Equilibrium Method

    唐四叶; 曹欣祥; 李仕辉

    2012-01-01

    The aim of this work was to determine the theta( 9) temperatures of chlorinated polypropylene in various solvents. Chlorinated polypropylene was separated into some fractions with different molecular weights using fractional precipitations by solvent/nonsolvent technique. The chlorinated polypropylene with different molecular weight was dissolved in different solvents at room temperature. The cloud point temperature of chlorinated polypropylene in ethylacetate, cyclohe.xane, butanone, 1,4 - dioxane were determined. The theta( 0) temperatures of chlorinated polypropylene in relative solvents were determined by linear regression analysis. The theta(0) temperatures of chlorinated polypropylene in ethylacetate, clohexane, butanone, 1,4 -dioxane were 362. 06 K, 354. 36 K, 351. 12 K and 349. 16 K respectively. The theta(0) temperature increased with the increase of interaction parameter.%本研究的目的是测定氯化聚丙烯在不同溶剂中的θ温度.用浊度法将氯化聚丙烯进行分级,得到相对分子质量不等的若干级分,将不同级分的氯化聚丙烯于室温下溶解在不同溶剂中,测定了不同级分的氯化聚丙烯在乙酸乙酯、环己烷、丁酮和1,4-二氧六环中的浊点温度,依据线性回归获得了氯化聚丙烯在乙酸乙酯、环己烷、丁酮和1,4-二氧六环中的θ温度.氯化聚丙烯在乙酸乙酯、环己烷、丁酮和二氧六环中的θ温度分别为362.06K、354.36K、351.12K和349.16K.θ温度随相互作用参数的增大而增大.

  15. Aggregation properties and thermodynamics of micellization of gemini surfactants with diethyl ether spacer in water and water–organic solvent mixed media

    Highlights: • Micellization behavior of gemini surfactants with diethyl ether spacer discussed. • Thermodynamic properties of the micellization of gemini surfactants discussed. • Effect of hydrocarbon tail length and diethyl ether spacer group demonstrated. • Effect of organic co-solvents (ethylene glycol and 1,4-dioxane) discussed. • Effect of temperature demonstrated. -- Abstract: The aggregation properties and thermodynamics of micellization of three cationic gemini surfactants (n–EO1–n) containing diethyl ether spacer group with varying carbon number (n = 12, 14 and 16) in the hydrophobic tails have been studied in water and water–organic solvents mixed media over the range of temperature (298.15 to 328.15) K using the conductometric method. Ethylene glycol (EG) and 1,4-dioxane (DO) were used as organic co-solvents with three different volume percentages due to their unique nature than other solvents. With increasing tail length, the critical micellar concentration (cmc) of gemini surfactants decreased. The effect of the diethyl ether spacer group on aggregation behaviour has been compared with other reported spacer groups. The micellization process is delayed in the presence of organic co-solvents as compared to pure water giving a positive value for the Gibbs energy of transfer (ΔGtranso). The degree of counter ion dissociation (α) increases with increasing tail length of gemini surfactants. It also increases with increase in the percentage of organic co-solvents and it is more prominent in DO–WR than EG–WR mixed media. The standard Gibbs energy of micellization (ΔGmo) is found to increase with increasing volume percentage of an organic co-solvent and also with decrease in the chain length of gemini surfactants. The ΔGmo has been correlated with Gordon parameter. The ΔGmo increases with increasing temperature which is more prominent in the presence of high percentage of an organic co-solvent and also in the presence of an organic co

  16. Dielectric behaviour of some amides and formamides dissolved in nonpolar solvents under static electric field

    S Sahoo; S K Sit

    2011-08-01

    Structural and associational aspects of polar amides () like formamide, acetamide, Nmethyl acetamide (NMA), N,N-dimethyl formamide (DMF), N,N-dimethyl acetamide (DMA) and acetanilide dissolved in the nonpolar solvent () benzene or 1,4-dioxan have been estimated from the measured static relative permittivity 0 and high-frequency permittivity ∞ at different weight fractions s of polar solute at 35°C under static electric field using Debye model of polar liquid molecule. The static dipole moments s are compared with s reported from conductivity method and theoretical theos to get exact cal $\\cdot$ theos of the molecules are predicted from the available bond angles and bond moments where difference in electron affinity exists between two adjacent atoms of a polar group due to inductive, mesomeric and electromeric effects in them. Solute–solute molecular association for NMA in benzene and solute–solvent association for other amides are ascertained to arrive at their conformational structures.

  17. Protective effect of black seed oil of nigella sativa in rats during tumour induction and radiotherapy

    the present study was conducted to evaluate the potency of nigella sativa freshly crushed seeds (0.42 g/kg body weight) or oil ( 2.5 ml/kg body weight) for preventing tumor induction through exposure of rats to a common pollutant (1,4- dioxane) as a promoter under condition of the presence of an initiator ( N-nitrosodiethylamine). the antitumor effect was evaluated alone or in combination with low doses of γ-irradiation as a route of cancer treatment. female swiss albino rats were administered orally twice weekly with nigella sativa before and during exposure of rats to the carcinogenic compounds. animals were exposed to 3 doses of radiation (3 Gy/dose) day after day 2 weeks before the end of the experiment . the animals were sacrificed after one week of radiation, homocysteine, glutathione, lipid peroxide, GGT activity, nitric oxide, total protein, albumin and bilirubin levels were estimated in blood after 7 and 12 months from the start of the experiment .this work also includes histopathological study.rats injected with the carcinogenic compounds showed marked elevation in homocysteine, GGT activity, nitric oxide, bilirubin and lipid peroxide levels accompanied by a significant decrease in glutathione, total proteins and albumin levels

  18. Improved process for the synthesis of [2,2]-paracyclophane

    Zhang, Long; Wang, Juan; Gao, Leng; Xu, Yulun; Gao, Weimin

    2006-01-01

    An improved method for the preparation of [2,2]-paracyclophane, which is the monomer of poly-p-xylene widely used as high quality electrical coating material, by Hoffmann elimination employing p-methyl-benzyl chloride and trimethyl amine as main raw materials was developed. Influence of solvent, reaction time, reaction temperature etal on the yield of paracyclophane was investigated experimentally. Suitable reaction parameters were obtained as follows: n(Alkali) : n(Quaternary ammonium) is 5:1; catalyst: 0.2% cupric salt; with 1,4-dioxane as solvent and 0.2% sodium borohydride as reducer, and N II as protection gas; reaction temperature 110°C, reaction time is 30 hr, at the condition, the yield of [2,2]-paracyclophane is 78.6%, its purity is over 99.5%, with melting point 284-285°C. Analysis results by IR and melting temperature measurement etal identify the substance synthesized is [2,2]-paracyclophane. And the materials used is industrially available and better yield was obtained comparing with the values present in the patent literatures.

  19. Synthesis and biological evaluation of some novel furan derivatives.

    Sen, Sandip; De, Biplab; Easwari, T S

    2014-11-01

    The present work involved cyclization of Schiff bases to azetidine-2-one and thiazolidine 4-one derivatives. The schiff bases (IIIa-j) were obtained upon reaction between electrophillic carbon atom of furfuraldehyde and nucleophillic nitrogen atom of amines. Azetidine-2-one derivatives (IVa-j) were obtained by reaction between imines and monochloro acetyl chloride in the presence of triethyl amine and 1, 4 dioxan. On the other hand, preparations of thiazolidine-4-ones (Va-j) were preceded by nucleophilic attack of sulphur of thioglycolic acid on imine carbon followed by intramolecular cyclization in the presence of SnCl2. The structures of the compounds were confirmed by spectral and elemental analysis. The biological evaluation of the compounds like anti-microbial, antioxidant, analgesic, CNS depressant and anti-diabetic activity were determined. From the pharmacological investigation it was found that out of all the compounds IVa, IVb, IVe, IVf, IVh,Va, Vb, Ve, Vf, Vh had shown more potent activity. PMID:25362600

  20. Synthesis and structural characterization of base-stabilized oligomeric heterovinylidenes.

    Leung, Wing-Por; Chiu, Wang-Kin; Mak, Thomas C W

    2013-08-19

    Metalation of the (iminophosphoranyl)phosphine PPh2CH2(PPh2═NSiMe3) (1) with an equimolar amount of n-BuLi afforded the monolithium salt [Li{CH(PPh2)(PPh2═NSiMe3)}(THF)2] (2). The reaction of 2 with GeCl2·1,4-dioxane has led to the formation of a germavinylene moiety, which trimerized to form a new heterocyclic cage compound, [{(PPh2═NSiMe3)(PPh2)C═Ge:}{(PPh2═NSiMe3)(PPh2)C}2Ge→Ge:] (3). A similar reaction of the lithium methanide complex 2 with SnCl2 afforded the stannavinylidene moiety, which underwent a "head-to-tail" cycloaddition to form a stable 1,3-distannacyclobutane, 4. A trapping reaction of 4 with diiron nonacarbonyl gave the novel iron stannavinylidene complex 5. The solid-state structure analysis of 5 reveals that it contains two stannavinylidene moieties bonded in a Sn-P "head-to-tail" fashion, with one of the tin(II) centers coordinating to a Fe(CO)4 moiety. The X-ray structures of 2-5 have been determined by X-ray crystallography. In addition, the dynamic behavior of 5 has been studied by means of variable-temperature (31)P and (119)Sn NMR spectroscopy. PMID:23924072

  1. Innovative Protocols for in SITU MTBE Degradation by Using Molecular Probes-An Enhanced Chemical-Bio Oxidation Technique

    Paul Fallgren

    2009-02-20

    In situ chemical oxidation (ISCO) is a common technology to cleanup petroleum hydrocarbon-contaminated soils and groundwater. Sodium percarbonate (SPC) is an oxidant which is activated by iron (Fe) to produce Fenton-like reactions. Western Research Institute, in conjunction with Regenesis and the U.S. Department of Energy, conducted a study that investigated the performance of a 'safe' oxidant, SPC, to cleanup groundwater and soils contaminated with petroleum hydrocarbons and associated contaminants (e.g., MTBE). Results from a field pilot test in Frenchglen, Oregon showed VOC concentrations in groundwater decreased substantially within 2 weeks after injecting activated SPC (RegenOx). A protocol was established for determining RegenOx TOD in soils and groundwater. Total oxidant demand tests were necessary to determine the correct dosage of RegenOx to apply in the field and sufficiently degrade the contaminants of concern. Bench studies with RegenOx showed this technology was effective in degrading diesel fuel and 1,4-dioxane. The Fe-silica activator (RegenOx Part B) was tested with another oxidant, sodium persulfate. Bench tests results showed the combination of sodium persulfate and RegenOx Part B was effective in reducing PCE, MTBE, benzene, and n-heptane concentrations in water. Overall, the results of this project indicated that most petroleum contaminants in soil and groundwater can be sufficiently degraded using the RegenOx technology.

  2. Photoinduced intramolecular charge transfer of sodium 4-(N,N-dimethylamino)benzenesulfonate

    林丽榕; 江云宝

    2000-01-01

    A new dual fluorescent N,N-dimethylaniline derivative, sodium 4-(N,N-dimethylamino)-benzenesulfonate (SDMAS), is reported. In SDMAS, the electron acceptor is linked to the phenyl ring via a sulfur atom at the para-position of the electron donor. It was found that SDMAS emits dual fluorescence only in highly polar solvent water but not in organic solvents such as formamide, methanol and acetonitrile. In organic solvents only a single-band emission at ca.360 nm was observed in the short wavelength region. The dual fluorescence of SDMAS in water was found at 365 and 475 nm, respectively. Introduction of organic solvent such as ethanol, acetonitrile, and 1,4-dioxane into aqueous solution of SDMAS leads to blue-shift and quenching of the long-wavelength emission. Measurements of steady-state and picosecond time-resolved fluorescence indicate that the long wavelength fluorescence is emitted from a charge transfer (CT) state that is populated from the locally excited (LE) state, with the latter giving off the

  3. Synthesis and properties of malic acid-containing functional polymers.

    Yamaoka, T; Hotta, Y; Kobayashi, K; Kimura, Y

    1999-01-01

    Poly-L-lactides containing beta-alkyl alpha-malate-units were prepared by ring-opening copolymerizations of L-lactide with 3-(s)-[(benzyloxycarbonyl)methyl]- (BMD) and 3-(s)-[(dodecyloxycarbonyl)methyl]-1,4-dioxane-2,5-diones (DMD). The solution-cast films of these copolymers were alkali-treated to form a carboxyl-functionalized surface on which cell-binding Arg-Gly-Asp tripeptide (RGD) was immobilized with dicyclohexylcarbodiimide as coupling agent. For the copolymer of L-lactide and BMD the benzyl groups were removed by catalytic hydrogenolysis to obtain a fully carboxyl-functionalized copolymer (PLGM), and RGD was immobilized on the surface of its cast film. All the RGD-immobilized films thus prepared exhibited improved cell attachment compared with the original films. The cell attachment increased with increasing amount of immobilized RGD, which depended on the composition of the alpha-malate units in the copolymer. The RGD-immobilized PLGM films were degraded rapidly during the cell culture, while the RGD-immobilized films of the beta-alkyl alpha-malate-containing polymers survived the cell culture with little degradation. The rate of hydrolysis increased with increasing content of alpha-malate units for both series, depending on the structure of the protecting groups of the beta-carboxyl. These results suggest that the RGD-immobilized polymers could be a new class of functional bioresorbable polymer having improved cell-attachment and adjustable hydrolysis rate. PMID:10416674

  4. DEVELOPMENT AND VALIDATION OF HPTLC METHOD FOR SIMULTANEOUS ANALYSIS OF LOPINAVIR AND RITONAVIR IN THEIR COMBINED TABLET DOSAGE FORM

    Mardia RB

    2012-03-01

    Full Text Available Simultaneous quantification of Lopinavir and Ritonavir in tablet by HPTLC method was developed andvalidated. The chromatograms were developed using a mobile phase of Chloroform: 1, 4 - Dioxane (7:3%v/v on pre-coated plate of silica gel GF aluminum TLC plate and quantified by densitometricabsorbance mode at 210 nm. The Rf value for lopinavir and ritonavir was 0.74 and 0.58 respectively.The linearity of the method was found to be within the concentration range of 160-960 ng/spot forLopinavir and for Ritonavir, it was 40-240 ng/spot. The lower limits of detection and quantificationwere 9.56 ng/spot and 28.96 ng/spot for Lopinavir and 6.82 ng/spot and 20.66 ng/spot for Ritonavir. Themethod was also validated for precision, specificity and recovery. This developed method was used toanalyze fixed-dose tablet (Lopimune, Cipla Ltd sample of Lopinavir and Ritonavir.

  5. THEORETICALLY EVALUATING THE FORMATION OF HYDROPHOBIC CLUSTERS IN CERTAIN ELEMENTS USING ULTRASONIC FREQUENCY

    J.THENNARASU

    2013-03-01

    Full Text Available Particularly the anomalous increase of ultrasound attenuation near the critical region of binary liquid mixtures has been widely studied. The solutions have been carried out at some temperature range with the frequency range of about 200 Hz/sec. The data can be described quantitatively in terms of the Relaxation process, which can be approximated as Ideal solutions. In the case of ethyl alcohol & Dioxane, all of the ultrasonic data are consistent with the formation of intermolecular Hydrogen bonding associated with thermodynamic and kinetic constants. The results are discussed together with corresponding data for the above solution from previous works. It was concluded that for the solvent effects in an aqueous alcohol binary mixture are limited almost entirely to the hydrophobic ground-state stabilization by the organic co-solvent. This can be evaluated in pure water with “hydrophobic” clusters of hydrocarbon portion of 1,4 Dioxane. The composition dependence of absorption is analyzed in the light of Gordon G.Hammes theory together with Eigen & Maeyer's solution model.

  6. A Validated HPTLC Method for Simultaneous Quantification of Nebivolol and Hydrochlorothiazide in Bulk and Tablet Formulation

    S. T. Kumbhar

    2011-01-01

    Full Text Available A HPTLC method for the estimation of Nebivolol (NBV and Hydrochlorothiazide (HCTZ has been developed. It employs aluminum backed silica gel 60 F254 TLC plates, (20 cm × 10 cm, layer thickness 0.2 mm pre-washed with methanol and mobile phase comprising of 1,4-dioxane: toluene: triethylamine (5:3:0.1 v/v. The developing solvent was run up to 80 mm in Camag chamber previously saturated with 10.0 ml of solvent mixture for 30 min. Densitometric scanning was then performed with Camag TLC Scanner-3 equipped with winCATS (version 1.3.0 at λ max 281 nm. The Rf values were found to be 0.75 and 0.43 for Nebivolol and Hydrochlorothiazide respectively. The limit of detection and limit of quantitation were found to be 43ng/spot & 130ng/spot for Nebivolol and 25ng/spot & 76ng/spot for Hydrochlorothiazide respectively. The % RSD of intra-day variation and inter day variation were 0.54 and 0.41 respectively for NBV and 0.46 and 0.39 for HCTZ respectively. The proposed method can also be used for routine quality control to accurately determine Nebivolol and Hydrochlorothiazide in bulk and tablet dosage form.

  7. Conventional and atom transfer radical copolymerization of phenoxycarbonylmethyl methacrylate-styrene and thermal behavior of their copolymers

    2007-08-01

    Full Text Available The atom transfer radical polymerization (ATRP of phenoxycarbonylmethyl methacrylate (PCMMA with styrene (St were performed in bulk at 110°C in the presence of ethyl 2-bromoacetate, cuprous(Ibromide (CuBr, and N,N,N’,N”,N”-pentamethyldiethyltriamine. Also, a series conventional free-radical polymerization (CFRP of PCMMA and styrene were carried out in the presence of 2,2’-azobisisobutyronitrile in 1,4-dioxane solvent at 60°C. The structure of homo and copolymers was characterized by IR, 1H and 13C-NMR techniques. The composition of the copolymers was calculated by 1H-NMR spectra. The average-molecular weight of the copolymers were investigated by Gel Permeation Chromatography (GPC. For copolymerization system, their monomer reactivity ratios were obtained by using both Kelen-Tüdõs and Fineman-Ross equations. Thermal analysis measurements of homo- and copolymers prepared CFRP and ATRP methods were measured by TGA-50 and DSC-50. Blends of poly(PCMMA and poly(St obtained via ATRP method have been prepared by casting films from dichlorormethane solution. The blends were characterized by differential scanning calorimetry. The initial decomposition temperatures of the resulting copolymers increased with increasing mole fraction of St.

  8. Preparation and characterization of biopolymers comprising chitosan-grafted-ENR via acid-induced reaction of ENR50 with chitosan

    M. R. H. Mas Haris

    2014-02-01

    Full Text Available This paper describes the first detailed tailored-approach for the preparation of biopolymers comprising chitosan (CTS grafted onto the backbone of epoxidized natural rubber (CTS-g-ENR. In a typical experiment, appropriate amount of CTS and AlCl3•6H2O was added to a specified amount of ENR50 (ENR with about 50% epoxy content dissolved in a dual-solvent consisting of 1,4-dioxane and water (97.5:2.5% v/v and the resulting mixture refluxed with continuous stirring for 6 hours. Nuclear magnetic resonance (NMR spectral analysis of a biocomposite, CTS-g-ENR-P1, revealed that its epoxy content is 22.36% which is considerably lower than 44.93% as determined for ENR50-control (ENR50 derivative obtained under similar experimental condition but in the absence of CTS. This means that the grafting of CTS onto the backbone of ENR had occurred. The revelation is affirmed by the presence of the characteristic absorption bands of CTS and ENR, and the appearance of new bands at 1219, 902 and 733 cm–1 in the Fourier transform infrared (FTIR spectrum of CTS-g-ENR-P1. Further evidence that CTS had been successfully grafted onto the backbone of ENR can be deduced and described in this paper from the data obtained by means of Differential Scanning Calorimetric analysis, Thermogravimetric analysis and Variable Pressure Scanning Electron Microscopy.

  9. The influence of γ-ray irradiation on the thermal stability and molecular weight of Poly(L-Lactic acid) and its nanocomposites

    Yıldırım, Yeliz; Oral, Ayhan

    2014-03-01

    The gamma (γ) radiation effects on the thermal properties of Poly(L-Lactic acid) (PLLA), and three PLLA nanocomposites containing 1, 3 and 5% montmorillonite MK10 clay were investigated in different solvents such as tetrahydrofuran, chloroform and 1,4 dioxane. The polymers were irradiated by gamma radiation at low absorbed doses of 1, 5, and 10 kGy. The thermal properties and molecular weight of the unirradiated and irradiated PLLA and its nanocomposites were characterized by Thermogravimetry (TG) and Gel Permeation Chromatography (GPC), respectively. The TG curves showed that the thermal degradation of the unirradiated PLLA and its nanocomposites occurred in only one stage. The activation energies of thermal degradation (E) for irradiated and unirradiated PLLA and its nanocomposites were determined by the Flynn-Wall-Ozawa (FWO) method. The E values of the polymer irradiated with gamma radiation seem to be smaller than those of unirradiated sample due to polymer bond scission. In addition, the calculated G values of the polymer and nanocomposites showed that the polymer structure was less stable when exposed to radiation with increasing % MK10 content.

  10. Occupational exposure to airborne chemical substances in paintings conservators

    Anna Jeżewska

    2014-02-01

    Full Text Available Background: This paper presents the results of the quantitative study of the airborne chemical substances detected in the conservator's work environment. Material and Methods: The quantitative tests were carried out in 6 museum easel paintings conservation studios. The air test samples were taken at various stages of restoration works, such as cleaning, doubling, impregnation, varnishing, retouching, just to name a few. The chemical substances in the sampled air were measured by the GC-FID (gas chromatography with flame ionization detector test method. Results: The study results demonstrated that concentrations of airborne substances, e.g., toluene, 1,4-dioxane, turpentine and white spirit in the work environment of paintings conservators exceeded the values allowed by hygiene standards. It was found that exposure levels to the same chemical agents, released during similar activities, varied for different paintings conservation studios. It is likely that this discrepancy resulted from the indoor air exchange system for a given studio (e.g. type of ventilation and its efficiency, the size of the object under maintenance, and also from the methodology and protection used by individual employees. Conclusions: The levels of organic solvent vapors, present in the workplace air in the course of painting conservation, were found to be well above the occupational exposure limits, thus posing a threat to the worker's health. Med Pr 2014;65(1:33–41

  11. Assessing acute toxicity of effluent from a textile industry and nearby river waters using sulfur-oxidizing bacteria in continuous mode.

    Gurung, Anup; Hassan, Sedky H A; Oh, Sang-Eun

    2011-10-01

    Bioassays are becoming an important tool for assessing the toxicity of complex mixtures of substances in aquatic environments in which Daphnia magna is routinely used as a test organism. Bioassays outweigh physicochemical analyses and are valuable in the decision-making process pertaining to the final discharge of effluents from wastewater treatment plants as they measure the total effect of the discharge which is ecologically relevant. In this study, the aquatic toxicity of a textile plant effluent and river water downstream from the plant were evaluated with sulfur-oxidizing bacterial biosensors in continuous mode. Collected samples were analysed for different physicochemical parameters and 1,4-dioxane was detected in the effluent. The effluent contained a relatively high chemical oxygen demand of 60 mg L(-1), which exceeded the limit set by the Korean government for industrial effluent discharges. Results showed that both the effluent and river waters were toxic to sulfur-oxidizing bacteria. These results show the importance of incorporating bioassays to detect toxicity in wastewater effluents for the sustainable management of water resources. PMID:22329151

  12. EFFECT OF SOLVENT ON THE BETA-O-4 BOND CLEAVAGE OF A LIGNIN MODEL COMPOUND BY TERT-BUTOXIDE UNDER MILD CONDITIONS

    Yuji Matsumoto

    2011-11-01

    Full Text Available The beta-O-4 bond cleavage of a non-phenolic β-O-4 type dimeric lignin model compound, 2-(2-methoxyphenoxy-1-(3,4-dimethoxyphenyl-ethanol (III, was examined in systems using potassium tert-butoxide as a base (0.5 mol/l and tert-butanol (tBuOH, dimethylsulfoxide, 1,4-dioxane, or tetrahydrofuran as a solvent. The β-O-4 bond of compound III was cleaved in any system at 30°C, and 2-methoxyphenol (II was liberated. The amount of compound II liberated was close to the quantitative yield on the basis of the amount of compound III that disappeared, except for the treatment in the t-BuOH system. The reaction rate was dependent on what solvent was used. Half-life periods for these systems were roughly about 6.0, 3.0, 0.7, and 0.2h, respectively. It seemed that the rates were very high when the polarity of the solvents was low. Two reaction products generated from the aromatic ring with two methoxyl groups of compound III, 4-acetyl-1,2-dimethoxybenzene and 3,4-dimethoxybenzoic acid, were detected in all the systems. A peculiar reaction product, 1,2-dimethoxybenzene, was detected in a fairly large quantity, only when the latter two solvents with low polarities were applied.

  13. Phosphazene-catalyzed ring-opening polymerization of ε-caprolactone: Influence of solvents and initiators

    Alamri, Haleema

    2014-01-01

    Phosphazene base (t-BuP2) catalysed metal-free ring-opening polymerization of ε-caprolactone (ε-CL) at room temperature with various protic initiators in different solvents was investigated. The polymerization proceeded, in most cases, in a controlled manner to afford poly(ε-caprolactone) with low dispersities and expected molecular weights. Kinetic studies showed that when a primary alcohol was used as an initiator the polymerization rate in different solvents followed the order of dichloromethane ≫ toluene > 1,4-dioxane ≈ tetrahydrofuran. Extremely fast polymerization of l-lactide (LLA), which was added as a second monomer, was observed in different solvents giving rise to poly(ε-caprolactone)-b- poly(l-lactide) diblock copolymers with neat PLLA blocks despite incomplete conversion of ε-CL. The dependence of polymerization rate on the concentrations of ε-CL and t-BuP2 was also revealed. In addition to primary alcohol, the feasibility of using other protic initiators, such as secondary alcohol (either on a small molecule or a polymer chain-end), (aliphatic/aromatic) amide, carboxylic acid, phenol and thiophenol, was also investigated. These studies provided important information for designing a metal-free route towards polyester-based (bio)materials. © 2014 the Partner Organisations.

  14. Effect of process variables on morphology and aerodynamic properties of voriconazole formulations produced by thin film freezing.

    Beinborn, Nicole A; Lirola, Hélène L; Williams, Robert O

    2012-06-15

    The particle engineering process, thin film freezing (TFF), was used to produce particulate voriconazole (VRC) formulations with enhanced properties. The effect of various processing parameters on the solid state properties and aerodynamic performance of the TFF-processed powders was investigated in order to evaluate the suitability of these formulations for dry powder inhalation and to optimize the aerodynamic properties. Thin film freezing of VRC solution without stabilizing excipients resulted in microstructured, crystalline low density aggregate particles with specific surface areas of approximately 10m(2)/g. Thin film freezing of VRC-PVP solutions produced nanostructured, amorphous low density aggregate particles with specific surface areas ranging from 15 to 180m(2)/g, depending on the solvent system composition, polymer grade, and drug to polymer ratio utilized. VRC formulations manufactured with 1,4-dioxane, with and without PVP K12, resulted in the lowest specific surface areas but displayed the best aerodynamic properties. Using a Handihaler(®) dry powder inhaler (DPI), microstructured crystalline TFF-VRC and nanostructured amorphous TFF-VRC-PVP K12 (1:2) displayed total emitted fractions of 80.6% and 96.5%, fine particle fractions of 43.1% and 42.4%, and mass median aerodynamic diameters of 3.5 and 4.5μm, respectively. PMID:22433472

  15. Copolymers of N-(4-bromophenyl-2-methacrylamide with 2-hydroxyethyl methacrylate

    2007-09-01

    Full Text Available The radical-initiated copolymerization of N-(4-bromophenyl-2-methacrylamide (BrPMAAm with 2-hydroxyethylmethacrylate (HEMA was carried out in 1,4-dioxane solution at 70°C using 2,2’-azobisisobutyronitrile (AIBN as an initiator with different monomer-to-monomer ratios in the feed. The copolymers were characterized by FTIR, 1H- and 13C-NMR spectral studies. Gel permeation chromatography was employed for estimating the weight average (Mw and number average (Mn molecular weights and polydispersity index (PDI of the copolymers. The copolymer composition was evaluated by nitrogen content (N for BrPMAAm-units in polymers, which allowed the determination of reactivity ratios. Monomer reactivity ratios for BrPMAAm (M1-HEMA (M2 pair were determined by the application of conventional linearization methods such as Fineman-Ross (F-R, Kelen-Tüdõs (KT and Extended Kelen-Tüdõs (EKT and a nonlinear error invariable model method using a computer program RREVM. The characterizations were done thermogravimetric analysis (TGA. The antimicrobial effects of polymers were also tested on various bacteria, and yeast.

  16. Solvent triggered structural diversity of triple-stranded helicates: single molecular magnets.

    Li, Hongfeng; Chen, Peng; Sun, Wenbin; Zhang, Lei; Yan, Pengfei

    2016-02-21

    Multiple-stranded helicates are of interest in respect of their simplicity in geometry and significance in biology and materials. Bis-β-diketones have shown their advantage in terms of structure and geometry in the construction of multiple-stranded helicates, but further studies on their properties are limited due to their poor crystallization. In this study, solvents are found to play a decisive role in the crystallization of triple-stranded helicates. [Dy2(BTB)3(H2O)4] is used as a precursor to solvent-dependently crystallize three complexes [Dy2(BTB)3(CH3OH)4]·3CH3OH (1), [Dy2(BTB)3(DME)2] (2) and [Dy2(BTB)3(DOA)(H2O)2]·4.5DOA (3) (BTB = 3,3'-bis(4,4,4-trifluoro-1,3-dioxobutyl)biphenyl), where the key structural motif of the triple-stranded helicate, [Dy2(BTB)3], is retained. Four methanol molecules are found to ligate to Dy(3+) ions in 1, while each Dy(3+) ion is chelated by one DME molecule in 2. Interestingly, it is observed that 1,4-dioxane as a bridge ligates to two adjacent Dy(3+) ions, giving rise to the formation of a 1D chain structure. Magnetic measurement shows that 1 and 2 display slow magnetic relaxation under zero dc field, while single molecular magnet behavior is obtained for 3 under an applied dc field of 2000 Oe. PMID:26781997

  17. A facile degradable linkage for timed drug delivery

    New drug delivery systems based on hydroxamic acid polymers were evaluated. The system support was the poly acryloyl chloride which was synthesized via free radical polymerization of acryloyl chloride in 1,4-dioxane, initiated with 2,2-azobisisobutyronitrile. Poly(N-alkyl substituted acrylamide) were synthesized in Poly(acryloyl chloride) was modified in two steps, the first is with N-hydroxysuccinimide to give the imide ester of poly(acryloyl). In the second step, the imide ester of poly(acryloyl) was reacted either with hydroxylamine or with (N-methyl hydroxylamine), respectively. The hydroxamic polymers were reacted with, the model drug, ketoprofen, in the presence of dicyclohexylcarbodiimide at -5 degree C. All products were characterized by elemental analysis, FTIR and 1 HNMR spectra. In vitro drug release study was performed at various ph and temperature to elucidate the influence of temperature and ph on the hydrolysis rate of the amido-ester bond that links the drug to the macromolecule. The amount of drug released from N-methyl hydroxamic acid polymers was higher than from hydroxamic acid polymers. All polymers showed higher drug release at 37 degree C than at room temperature (25 degree C) and at higher ph

  18. Thermophysical properties of binary mixtures of N,N-dimethylformamide with three cyclic ethers

    Sinha Biswajit

    2013-01-01

    Full Text Available Densities and viscosities of the binary mixtures consisting of tetrahydrofuran (THF, 1,3-dioxolane (1,3-DO and 1,4-dioxane (1,4-DO with N,N-dimethylformamide (DMF over the entire range of composition were measured at temperatures 298.15, 308.15 and 318.15 K and at atmospheric pressure. Ultrasonic speeds of sound of these binary mixtures were measured at ambient temperature and atmospheric pressure (T = 298.15 K and P = 1.01×105 Pa. The various experimental data were utilized to derive excess molar volumes (VmE, excess viscosities (ηE, and excess isentropic compressibilities (κsE. Using the excess molar volumes (VmE, excess partial molar volumes (and and excess partial molar volumes at infinite dilution (and of each liquid component in the mixtures were derived and discussed. Excess molar volumes (VmE as a function of composition at ambient temperature and atmospheric pressure were used further to test the applicability of the Prigogine-Flory-Patterson (PFP theory to the experimental binaries. The excess properties were found to be either negative or positive depending on the nature of molecular interactions and structural effects of liquid mixtures. Em,1V Em,2VE0,m,1VE0,m,2V.

  19. Muscadine grape seed oil as a novel source of tocotrienols to reduce adipogenesis and adipocyte inflammation.

    Zhao, Lu; Yagiz, Yavuz; Xu, Changmou; Lu, Jiang; Chung, Soonkyu; Marshall, Maurice R

    2015-07-01

    Tocotrienols are unsaturated forms of vitamin E previously shown to reduce adipogenesis and adipose inflammation. In this study, muscadine grape seed oil (MGSO) was identified as a novel source of tocotrienols containing significant amounts of α- and γ-tocotrienol (T3) with minor seasonal changes. The aim of this study was to assess the anti-adipogenic and anti-inflammatory potential of MGSO by using primary human adipose-derived stem cells (hASCs). Differentiating hASCs were treated with MGSO and compared with rice bran and olive oil. Accumulation of triglyceride was significantly lower in MGSO-treated hASCs than rice bran and olive oils. A tocotrienol rich fraction (TRF) from MGSO was prepared by solid phase extraction and eluted with 15% 1,4-dioxane in hexane. The MGSO-derived TRF treatment significantly reduced mRNA and protein expression that are crucial to adipogenesis (e.g., PPARγ and aP2) in hASCs. Furthermore, TRF from MGSO markedly reduced LPS-induced proinflammatory gene expression in human adipocytes and cytokine secretion to the medium (IL-6 and IL-8). Collectively, our work suggests that MGSO is a stable and reliable natural source of T3 and MGSO may constitute a new dietary strategy to attenuate obesity and its associated adipose inflammation. PMID:26073057

  20. Fabricating a pearl/PLGA composite scaffold by the low-temperature deposition manufacturing technique for bone tissue engineering

    Here we developed a composite scaffold of pearl/poly(lactic-co-glycolic acid) (pearl/PLGA) utilizing the low-temperature deposition manufacturing (LDM). LDM makes it possible to fabricate scaffolds with designed microstructure and macrostructure, while keeping the bioactivity of biomaterials by working at a low temperature. Process optimization was carried out to fabricate a mixture of pearl powder, PLGA and 1,4-dioxane with the designed hierarchical structures, and freeze-dried at a temperature of -40 deg. C. Scaffolds with square and designated bone shape were fabricated by following the 3D model. Marrow stem cells (MSCs) were seeded on the pearl/PLGA scaffold and then cultured in a rotating cell culture system. The adhesion, proliferation and differentiation of MSCs into osteoblasts were determined using scanning electronic microscopy, WST-1 assay, alkaline phosphatase activity assay, immunofluorescence staining and real-time reverse transcription polymerase chain reaction. The results showed that the composite scaffold had high porosity (81.98 ± 3.75%), proper pore size (micropores: <10 μm; macropore: 495 ± 54 μm) and mechanical property (compressive strength: 0.81 ± 0.04 MPa; elastic modulus: 23.14 ± 0.75 MPa). The pearl/PLGA scaffolds exhibited better biocompatibility and osteoconductivity compared with the tricalcium phosphate/PLGA scaffold. All these results indicate that the pearl/PLGA scaffolds fulfill the basic requirements of bone tissue engineering scaffold.

  1. Mechanism of Positive Allosteric Modulators Acting on AMPA Receptors

    Jin,R.; Clark, S.; Weeks, A.; Dudman, J.; Gouaux, E.; Partin, K.

    2005-01-01

    Ligand-gated ion channels involved in the modulation of synaptic strength are the AMPA, kainate, and NMDA glutamate receptors. Small molecules that potentiate AMPA receptor currents relieve cognitive deficits caused by neurodegenerative diseases such as Alzheimer's disease and show promise in the treatment of depression. Previously, there has been limited understanding of the molecular mechanism of action for AMPA receptor potentiators. Here we present cocrystal structures of the glutamate receptor GluR2 S1S2 ligand-binding domain in complex with aniracetam [1-(4-methoxybenzoyl)-2-pyrrolidinone] or CX614 (pyrrolidino-1, 3-oxazino benzo-1, 4-dioxan-10-one), two AMPA receptor potentiators that preferentially slow AMPA receptor deactivation. Both potentiators bind within the dimer interface of the nondesensitized receptor at a common site located on the twofold axis of molecular symmetry. Importantly, the potentiator binding site is adjacent to the 'hinge' in the ligand-binding core 'clamshell' that undergoes conformational rearrangement after glutamate binding. Using rapid solution exchange, patch-clamp electrophysiology experiments, we show that point mutations of residues that interact with potentiators in the cocrystal disrupt potentiator function. We suggest that the potentiators slow deactivation by stabilizing the clamshell in its closed-cleft, glutamate-bound conformation.

  2. Synthesis of a new ionic imprinted polymer for the extraction of uranium from seawater

    The ionic imprinted polymer (IIP) of uranyl ion (UO22+) as the template was synthesized by the formation of binary complexes of UO22+ with 2,4-dioxopentan-3-yl methacrylate as functional monomer followed by thermal copolymerization with ethylene glycol dimethacrylate as cross-linking monomer in the presence of 2,2'-azobisisobutyronitrile as initiator and 1,4-dioxane as porogenic solvent. 50 mmol L-1 HCl solution was used to leach out UO22+ ions from the IIP. Similarly, the control polymer was prepared under identical experimental conditions without using UO22+ ions. The above synthesized polymers were characterized by infra-red spectroscopy, thermo-gravimetric analysis and Barrett-Emmett-Teller surface area measurement. The maximum adsorption capacities of IIP and CP in (NH4)4[UO2(CO3)3] solution were 15.3 and 11.2 mg U g-1, respectively. The kinetics of adsorption followed a pseudo-second-order rate equation. The prepared IIP was successfully used to extract uranium from real seawater sample. (author)

  3. Terpene product derivatives from isoprene oligomerization

    Morikawa, H.; Kitazume, S.

    1979-12-01

    Products of isoprene oligomerization at 65/sup 0/-95/sup 0/C with modified Ziegler-type catalysts were separated by distillation into dimer (40/sup 0/-60/sup 0/C bp), trimer (115/sup 0/-140/sup 0/C), and polymer fractions, which were analyzed by gas chromatography. The ratio of cycle to linear dimers, i.e., 2,4-dimethyl-4- vinyl-1-cyclohexene (DMVCH) and 2,6-dimethyl- 1,3-6-octatriene (DMOT), was correlated with the electronic factor (basicity) of the ligands. In pilot-plant studies, maximum yields of DMVCH, 66% at 80/sup 0/C, and DMOT, 64% at 75/sup 0/C, were obtained with Ziegler systems composed of titanium tetrachloride or tetraiodide, respectively, plus diethylaluminum chloride (DEAC) and 1,4-dioxane. The yields of cyclotrimers, mainly 1,6,9- (A) and 1,5,9- (B) trimethyl- 1,5,9-cyclodecatrienes, depended also on the steric factor (cone angle) of the ligands and the nature of the central atom and were highest, 65% at 65/sup 0/C and 63% at 95/sup 0/C, respectively, with catalysts composed of titanium trichloride, p-NO/sub 2/,o-chlorobenzaldehyde, and DEAC (A) and nickel octooate, triethylaluminum, and certain phosphines (B). Potential applications of oligomer derivatives are discussed.

  4. The radiolysis in the nuclear-chemical extraction systems

    In the first part, the progress of research works including spent fuel reprocessing of nuclear power reactor, process chemistry of uranium, plutonium, actinides, lanthanoids and fission products and radiation chemistry including photochemistry is reviewed. in the second part, works of the author in radiation processes and photochemical processes in extraction systems used in spent fuel reprocessing of nuclear power reactor, (namely) in tri-n-butylphosphate, di-n-butylphosphate, tritolylphosphate, di-n-butyl-butylphosphonate bis(2-ethylhexyl)phosphoric acid, cobalt(III) dicarbollide, nitrobenzene, carbon tetrachloride, chlorobenzene and its one-phase and liquid-liquid two-phase systems with water or nitric acid solutions, and crown-ethers (12-crown-4, 15-crown-5, dicyclohexano-24-crown-8 and their analogues tetrahydrofuran and 1,4-dioxane) which were studied with GC-MS, GC-FTIR, HPLC, capillary isotachophoresis, UV-VIS and EPR spectroscopy, preparative or laser flash photolysis, steady state and pulse radiolysis and other methods are reviewed.(author) The 24 papers is presented in the appendix. 469 refs., 17 tabs. 2 figs

  5. Two 2-D 36 tessellated metal-organic frameworks constructed from trimetallic clusters and dicarboxylate ditopic links

    Two metal-organic framework compounds, [Zn3(1,4-BDC)3(Py)2].2(1,4-dioxane) (MOF-CJ6) and [Cd3(bpdc)3(H2O)2] (MOF-CJ7), have been solvothermally synthesized and characterized by single crystal X-ray diffraction, X-ray powder diffraction, ICP, IR and photoluminescence spectroscopy analyses, respectively. MOF-CJ6 crystallizes in monoclinic, space group P2(1)/n (no. 14) with a = 14.6886(14) A, b = 9.6194(6) A, c = 15.9161(16) A and β = 105.687(6)o. Its framework can be described as a 2-D 36 tessellated net based on the assembly of trimeric Zn3(CO2)6 clusters and 1,4-benzenedicarboxylates ditopic links. The 2-D nets can be further linked into a novel 3-D supramolecular hexagonal lattice (hex) network through π-π packing interaction. MOF-CJ7 crystallizes in trigonal, space group R-3 (no. 148) with a = 14.1129(8) A, b = 14.1129(8) A, c = 20.1168(13) A and γ = 120o. MOF-CJ7 exhibits analogous framework topology with that of MOF-CJ6, consisting of trimeric Cd3(CO2)6 clusters and 4,4'-biphenyldicarboxylate links

  6. Electrooptical Absorption Measurements (EOAM) Testify Existence of two Conformers of Prodan and Laurdan with Different Dipole Moments in Equilibrium Ground and Franck-Condon Excited State.

    Nemkovich, N A; Detert, H; Roeder, N

    2016-09-01

    The results from the electrooptical absorption measurements (EOAM) on the equilibrium ground and excited Franck-Condon state dipole moments of Prodan and Laurdan in 1,4-dioxane are presented. As follows from experiments Prodan and Laurdan in the equilibrium ground and excited Franck-Condon state have two conformers with considerably different dipole moments. The electrical dipole moments and the transition dipole moment, obtained from the short-wavelength region of the absorption spectrum are parallel. The electrical dipole moments measured at the long-wavelength spectral region are parallel to each other but not parallel to the transition dipole moment m a. The angle θ between the transition dipole moment m a and the dipole moment in the equilibrium ground state μ g of the long-wavelength conformer is about 30(0) for both probes. Obtained results evidence that donor-acceptor pairs of the short-wavelength and long-wavelength conformers are not located on the same axis. Two low-energy conformers of Prodan have been found by density functional theory (DFT) calculations, differing in the orientation of the carbonyl group towards the naphthalene system. PMID:27396483

  7. Responses of the L5178Y mouse Lymphoma cell forward mutation assay. V: 27 coded chemicals.

    McGregor, D B; Brown, A G; Howgate, S; McBride, D; Riach, C; Caspary, W J

    1991-01-01

    Twenty-seven chemicals were tested for their mutagenic potential in the L5178Y tk+/tk- mouse lymphoma cell forward mutation assay using procedures based upon those described by McGregor et al. (McGregor DB, Martin R, Cattanach P, Edwards I, McBride D, Caspary WJ (1987): Environ Mol Mutagen 9:143-160). Cultures were exposed to the chemicals for 4 hr, then cultured for 2 days before plating in soft agar with or without trifluorothymidine (TFT), 3 micrograms/ml. The chemicals were tested at least twice. Statistically significant responses were obtained with acid orange 10, aniline, benzaldehyde, o-chloroaniline, chlorodibromomethane, cytembena, 1,2-dibromo-4-(1,2-dibromomethyl) cyclohexane, dieldrin, lithocholic acid, oxytetracycline, phenazopyridine HCl, 1-phenyl-3-methyl-5-pyrazolone, sodium diethyldithiocarbamate, solvent yellow 14, tetraethylthiuram disulfide (disulfiram), 2,4-toluene diisocyanate, and 2,6-toluene diisocyanate. Apart from phenazopyridine HCl, acid orange 10, and solvent yellow 14, rat liver S9 mix was not a requirement for the mutagenic activity of these compounds. Chemical not identified as mutagens were N-4-acetylaminofluorene, chlorpheniramine maleate, chloropropamide, 1,4-dioxane, endrin, ethylene glycol, iron dextran, methapyrilene, sodium(2-ethylhexyl)alcohol PMID:1902415

  8. RING OPENING COPOLYMERIZATION OF SUCCINIC ANHYDRIDE-ETHYLENE OXIDE BY Al (Ⅲ) ORGANOMETALLIC CATALYSTS

    CHEN Xianhai; ZHANG Yifeng; SHEN Zhiquan

    1997-01-01

    Ring opening copolymerization of succinic anhydride (SA) with ethylene oxide (EO)was successfully carried out by using a series of aluminum-based catalyst in 1,4-dioxane at 62±2℃. The results showed that in-situ AlR3-H2O (R=ethyl, iso-butyl) catalysts gave higher molecular weight ((-M)w ~ 104), while Al(OR)3 catalysts gave the higher alternating copolymer structure with slightly lower molecular weight. The in-situ AlR3-H2O systems have been evaluated in more detail for the reaction which showed the optimum H2O/Al molar ratio to be 0.5. The copolymers with different composition (FSA/FEO = 36/64 to 45/55 mol/mol) were synthesized by using different monomer feed ratio. The melting point (Tm), glass transition temperature (Tg) and enthalpy of fusion (ΔHf) of these copolymers are depended on the copolymer composition and in the range of 87~ 102℃,-12 ~ -18℃, and 37 ~ 66J/g, respectively. The second heating scan of DSC also indicated that the higher alternating copolymer was more easily recrystallized. The onset decomposition temperature was more than 300℃ under nitrogen and influenced by the copolymer composition.

  9. 表面活性剂对水溶性氮杂环卡宾钯催化Suzuki反应的影响%Influence of surfactant for the water-soluble N-heterocyclic carbene palladium catalyzed Suzuki reaction in water

    柳云玲; 于宏伟; 贾莉; 施继成

    2012-01-01

    The influence of surfactant for the N-heterocyclic carbene palladium catalyst(5) with 15 of glycol units has been evaluated.It was found that those routine surfactants can recover the activity of the catalyst 5 for Suzuki reaction carried out in water to the level in 1,4-dioxane,affording another way to improve the activity of 5 in water.%开展了添加表面活性剂对带15个左右的乙二醇单元的氮杂环卡宾钯催化剂(5)在水介质中催化Suzuki偶联反应性能的影响研究;发现常见的阳离子或阴离子表面活性剂均可将催化剂5在水介质中的催化性能恢复到在二氧六环中的水平;故发现了一条提高催化剂5在水介质的性能途径.

  10. Development of surrogate correlation models to predict trace organic contaminant oxidation and microbial inactivation during ozonation.

    Gerrity, Daniel; Gamage, Sujanie; Jones, Darryl; Korshin, Gregory V; Lee, Yunho; Pisarenko, Aleksey; Trenholm, Rebecca A; von Gunten, Urs; Wert, Eric C; Snyder, Shane A

    2012-12-01

    The performance of ozonation in wastewater depends on water quality and the ability to form hydroxyl radicals (·OH) to meet disinfection or contaminant transformation objectives. Since there are no on-line methods to assess ozone and ·OH exposure in wastewater, many agencies are now embracing indicator frameworks and surrogate monitoring for regulatory compliance. Two of the most promising surrogate parameters for ozone-based treatment of secondary and tertiary wastewater effluents are differential UV(254) absorbance (ΔUV(254)) and total fluorescence (ΔTF). In the current study, empirical correlations for ΔUV(254) and ΔTF were developed for the oxidation of 18 trace organic contaminants (TOrCs), including 1,4-dioxane, atenolol, atrazine, bisphenol A, carbamazepine, diclofenac, gemfibrozil, ibuprofen, meprobamate, naproxen, N,N-diethyl-meta-toluamide (DEET), para-chlorobenzoic acid (pCBA), phenytoin, primidone, sulfamethoxazole, triclosan, trimethoprim, and tris-(2-chloroethyl)-phosphate (TCEP) (R(2) = 0.50-0.83) and the inactivation of three microbial surrogates, including Escherichia coli, MS2, and Bacillus subtilis spores (R(2) = 0.46-0.78). Nine wastewaters were tested in laboratory systems, and eight wastewaters were evaluated at pilot- and full-scale. A predictive model for OH exposure based on ΔUV(254) or ΔTF was also proposed. PMID:23062789

  11. Thermodynamics of Ru(III)-EDTA catalyzed homogeneous oxidation of adamantane by molecular oxygen

    The kinetics and thermodynamics of Ru(III)-EDTA catalyzed oxidation of adamantane by molecular oxygen (pH = 1.5 to 3.0) has been investigated in the temperature range 288-313 K in presence and absence of ascorbic acid in a 1:3 (v/v) mixture of water and 1.4 dioxane. The rate of oxidation is first order with respect to the concentration of catalyst, ascorbic acid and molecular oxygen; fractional order with respect to adamantane and inverse first order with respect to hydrogen ion. In the absence of ascorbic acid the reaction orders with respect to the concentrations of adamantane, dioxygen and hydrogen ion were one, half and zero respectively. Thermodynamic quantities associated with catalytic systems Ru(III)-EDTA-O2 and Ru(III)-EDTA-ascorbate-O2 indicated that activation parameters become more favourable in the presence ascorbic acid where heterolytic cleavage of the O-O bond takes place. In absence of ascorbic acid concerted homolytic cleavage of the O-O bond is associated with higher-activation parameters. (author)

  12. Fragranced consumer products and undisclosed ingredients

    Fragranced consumer products-such as air fresheners, laundry supplies, personal care products, and cleaners-are widely used in homes, businesses, institutions, and public places. While prevalent, these products can contain chemicals that are not disclosed to the public through product labels or material safety data sheets (MSDSs). What are some of these chemicals and what limits their disclosure? This article investigates these questions, and brings new pieces of evidence to the science, health, and policy puzzle. Results from a regulatory analysis, coupled with a chemical analysis of six best-selling products (three air fresheners and three laundry supplies), provide several findings. First, no law in the U.S. requires disclosure of all chemical ingredients in consumer products or in fragrances. Second, in these six products, nearly 100 volatile organic compounds (VOCs) were identified, but none of the VOCs were listed on any product label, and one was listed on one MSDS. Third, of these identified VOCs, ten are regulated as toxic or hazardous under federal laws, with three (acetaldehyde, chloromethane, and 1,4-dioxane) classified as Hazardous Air Pollutants (HAPs). Results point to a need for improved understanding of product constituents and mechanisms between exposures and effects

  13. Cultivation conditions and properties of extracellular crude lipase from the psychrotrophic fungus Penicillium chrysogenum 9'.

    Bancerz, R; Ginalska, G; Fiedurek, J; Gromada, A

    2005-06-01

    Among 97 fungal strains isolated from soil collected in the arctic tundra (Spitsbergen), Penicillium chrysogenum 9' was found to be the best lipase producer. The maximum lipase activity was 68 units mL(-1) culture medium on the fifth day of incubation at pH 6.0 and 20 degrees C. Therefore, P. chrysogenum 9' was classified as a psychrotrophic microorganism. The non-specific extracellular lipase showed a maximum activity at 30 degrees C and pH 5.0 for natural oils or at pH 7.0 for synthetic substrates. Tributyrin was found to be the best substrate for lipase, among those tested. The Km and Vmax were calculated to be 2.33 mM and 22.1 units mL(-1), respectively, with tributyrin as substrate. The enzyme was inhibited more by EDTA than by phenylmethylsulfonyl fluoride and was reactivated by Ca2+. The P. chrysogenum 9' lipase was very stable in the presence of hexane and 1,4-dioxane at a concentration of 50%, whereas it was unstable in presence of xylene. PMID:15895263

  14. Epistemology of contaminants of emerging concern and literature meta-analysis.

    Halden, Rolf U

    2015-01-23

    A meta-analysis was conducted to inform the epistemology, or theory of knowledge, of contaminants of emerging concern (CECs). The CEC terminology acknowledges the existence of harmful environmental agents whose identities, occurrences, hazards, and effects are not sufficiently understood. Here, data on publishing activity were analyzed for 12 CECs, revealing a common pattern of emergence, suitable for identifying past years of peak concern and forecasting future ones: dichlorodiphenyltrichloroethane (DDT; 1972, 2008), trichloroacetic acid (TCAA; 1972, 2009), nitrosodimethylamine (1984), methyl tert-butyl ether (2001), trichloroethylene (2005), perchlorate (2006), 1,4-dioxane (2009), prions (2009), triclocarban (2010), triclosan (2012), nanomaterials (by 2016), and microplastics (2022 ± 4). CECs were found to emerge from obscurity to the height of concern in 14.1 ± 3.6 years, and subside to a new baseline level of concern in 14.5 ± 4.5 years. CECs can emerge more than once (e.g., TCAA, DDT) and the multifactorial process of emergence may be driven by inception of novel scientific methods (e.g., ion chromatography, mass spectrometry and nanometrology), scientific paradigm shifts (discovery of infectious proteins), and the development, marketing and mass consumption of novel products (antimicrobial personal care products, microplastics and nanomaterials). Publishing activity and U.S. regulatory actions were correlated for several CECs investigated. PMID:25294779

  15. Triphenylene discotic liquid crystal trimers synthesized by Co2(CO8-catalyzed terminal alkyne [2 + 2 + 2] cycloaddition

    Bin Han

    2013-12-01

    Full Text Available The synthesis of star-shaped discotic liquid crystal trimers using Co2(CO8-catalyzed terminal alkyne [2 + 2 + 2] cycloaddition reaction is reported. The trimers consist of three triphenylene discotic units linked to a central 1,2,4-trisubstituted benzene ring via flexible spacers. The trimers were synthesized in the yields up to 70% by mixing the monomers with 10 mol % of Co2(CO8 as the catalyst in refluxing 1,4-dioxane. The liquid crystalline properties were investigated by using polarizing optical microscopy (POM, differential scanning calorimetry (DSC and X-ray diffraction (XRD. Trimer 4 with an ester connecting group and a longer spacer exhibited a rectangular columnar mesophase, while 5b and 5c possessing an ether linkage and a shorter spacer display a hexagonal columnar mesophase. The connecting functional group and the length of the flexible spacer between the central benzene ring and the triphenylene units have pivotal influence on the mesomorphism.

  16. Solubilities of some organic solutes in 1-ethyl-3-methylimidazolium acetate. Chromatographic measurements and predictions from COSMO-RS

    Highlights: ► New solubility data are reported. ► Two experimental procedures for measuring solubilities are used. ► The experimental results from both procedures are compared. ► Experiments are compared with the theoretical calculations. - Abstract: Infinite-dilution activity coefficients and Henry’s constants for several organic solutes in 1-ethyl-3-methylimidazolium acetate [EMIM][Ac] were measured from T = 313 K to T = 413 K using two types of gas–liquid chromatography columns: packed columns and an open tubular wall-coated (OTWC) column. The organic solutes include n-hexane, 1-hexene, cyclohexane, heptane, benzene, toluene, ethyl acetate, tetrahydrofuran, 1,4-dioxane, acetonitrile, nitromethane, 1,2-methoxyethane, 1-propanol, 2-propanol, t-butanol and t-amyl alcohol. Results using packed columns are in good agreement with those using the OTWC column. However, there is a useful advantage associated with an OTWC column: for solutes such as alcohols, that have strong interactions with the stationary phase, measurements are faster due to their shorter retention time compared to those in packed columns.

  17. Supramolecular Assemblies from Poly(styrene-block-poly(4-vinylpyridine Diblock Copolymers Mixed with 6-Hydroxy-2-naphthoic Acid

    Jean-François Gohy

    2013-06-01

    Full Text Available Supramolecular assemblies involving interaction of a small organic molecule, 2-hydroxy-6-Naphthoic acid (HNA, with poly(styrene-block-poly(4-vinylpyridine (PS-b-P4VP diblock copolymers are utilized to obtain micellar structures in solution, nanostructured thin films on flat substrates and, finally, nanoporous thin films. The formation of hydrogen bonds between HNA and the poly(4-vinylpyridine (P4VP blocks is confirmed by spectroscopic measurements. The accordingly P4VP/HNA hydrogen-bonded complexes are poorly soluble in 1,4-dioxane, resulting in the formation of micellar structures with a P4VP/HNA core and a polystyrene (PS corona. Those micelles have been spin-coated onto silicon wafers, resulting in nanostructured thin films consisting of P4VP/HNA dot-like features embedded in a PS matrix. The morphology of those films has been tuned by solvent annealing. Selective dissolution of HNA by methanol results in the formation of a nanoporous thin film. The P4VP/HNA nanodomains have been also cross-linked by borax, and the thin films have been further dissolved in a good solvent for PS, leading to micelles with a structure reminiscent of the thin films.

  18. Preparation and properties of cellulose triacetate forward osmosis membrane%三乙酸纤维素正渗透膜的制备与性能

    解利昕; 辛婧; 解奥

    2014-01-01

    Cellulose triacetate based membranes for forward osmosis were prepared by immersion precipitation. The polymer solution consisted of cellulose triacetate as the membrane material, 1,4-dioxane and acetone as solvent,methanol and lactic acid as additives. Casting composition and preparation conditions-1,4-dioxane/acetone ratio,lactic acid content,evaporation time,casting thickness and annealing temperature-were tested for their effects on membrane performance. The optimized membrane showed 14.10L/(m2·h) water flux and 0.031mol/(m2·h) reverse solute flux using a feed solution of pure water and draw solution of 0.56mol/L CaCl2. When 0.1mol/L NaCl was used as the feed solution and 4mol/L glucose was used as the draw solution,water flux was above 5L/(m2·h) and rejection for NaCl was above 99%. The optimized membrane had a more hydrophilic surface, higher water flux,higher salt resistance and better membrane performance than the HTI membrane.%以三乙酸纤维素(CTA)为膜材料,1,4-二氧六环、丙酮为溶剂,甲醇、乳酸为添加剂,采用相转换法制备了三乙酸纤维素正渗透膜。研究了不同1,4-二氧六环/丙酮配比、添加剂乳酸含量、挥发时间、膜厚度、热处理温度条件下正渗透膜性能的变化规律。研究表明,当采用纯水为原料液,0.56mol/L CaCl2为汲取液时,优化制备的CTA正渗透膜的水通量达到14.10L/(m2·h),溶质反扩散量为0.031mol/(m2·h);采用0.1mol/L NaCl为原料液,4mol/L葡萄糖为汲取液时,优化制备的CTA正渗透膜的水通量保持在5L/(m2·h)以上,对NaCl的截留率大于99%。CTA正渗透膜相比于HTI膜,具有较高的亲水性、水通量、截留率,稳定性更好。

  19. Dithio- and Diselenophosphinate Thorium(IV) and Uranium(IV) Complexes: Molecular and Electronic Structures, Spectroscopy, and Transmetalation Reactivity.

    Behrle, Andrew C; Kerridge, Andrew; Walensky, Justin R

    2015-12-21

    We report a comparison of the molecular and electronic structures of dithio- and diselenophosphinate, (E2PR2)(1-) (E = S, Se; R = (i)Pr, (t)Bu), with thorium(IV) and uranium(IV) complexes. For the thorium dithiophosphinate complexes, reaction of ThCl4(DME)2 with 4 equiv of KS2PR2 (R = (i)Pr, (t)Bu) produced the homoleptic complexes, Th(S2P(i)Pr2)4 (1S-Th-(i)Pr) and Th(S2P(t)Bu2)4 (2S-Th-(t)Bu). The diselenophosphinate complexes were synthesized in a similar manner using KSe2PR2 to produce Th(Se2P(i)Pr2)4 (1Se-Th-(i)Pr) and Th(Se2P(t)Bu2)4 (2Se-Th-(t)Bu). U(S2P(i)Pr2)4, 1S-U-(i)Pr, could be made directly from UCl4 and 4 equiv of KS2P(i)Pr2. With (Se2P(i)Pr2)(1-), using UCl4 and 3 or 4 equiv of KSe2P(i)Pr2 yielded the monochloride product U(Se2P(i)Pr2)3Cl (3Se-U(iPr)-Cl), but using UI4(1,4-dioxane)2 produced the homoleptic U(Se2P(i)Pr2)4 (1Se-U-(i)Pr). Similarly, the reaction of UCl4 with 4 equiv of KS2P(t)Bu2 yielded U(S2P(t)Bu2)4 (2S-U-(t)Bu), whereas the reaction with KSe2P(t)Bu2 resulted in the formation of U(Se2P(t)Bu2)3Cl (4Se-U(tBu)-Cl). Using UI4(1,4-dioxane)2 and 4 equiv of KSe2P(t)Bu2 with UCl4 in acetonitrile yielded U(Se2P(t)Bu2)4 (2Se-U-(t)Bu). Transmetalation reactions were investigated with complex 2Se-U-(t)Bu and various CuX (X = Br, I) salts to yield U(Se2P(t)Bu2)3X (6Se-U(tBu)-Br and 7Se-U(tBu)-I) and 0.25 equiv of [Cu(Se2P(t)Bu2)]4 (8Se-Cu-(t)Bu). Additionally, 2Se-U-(t)Bu underwent transmetalation reactions with Hg2F2 and ZnCl2 to yield U(Se2P(t)Bu2)3F (6) and U(Se2P(t)Bu2)3Cl (4Se-U(tBu)-Cl), respectively. The molecular structures were analyzed using (1)H, (13)C, (31)P, and (77)Se NMR and IR spectroscopy and structurally characterized using X-ray crystallography. Using the QTAIM approach, the electronic structure of all homoleptic complexes was probed, showing slightly more covalent bonding character in actinide-selenium bonds over actinide-sulfur bonds. PMID:26636609

  20. Thin nanostructured crystalline TiO{sub 2} films and their applications in solar cells

    Cheng Yajun

    2007-06-15

    Research on thin nanostructured crystalline TiO{sub 2} films has attracted considerable interests because of their intriguing physical properties and potential applications in photovoltaics. Nanostructured TiO{sub 2} film plays an important role in the TiO{sub 2} based dye-sensitized solar cells because they act as a substrate for the adsorption of dye molecules and a matrix for the transportation of electrons as well. Thus they can influence the solar cell performance significantly. Consequently, the control of the morphology including the shape, size and size distribution of the TiO{sub 2} nanostructures is critical to tune and optimize the performance of the solar cells. To control the TiO{sub 2} morphology, a strategy using amphiphilic block copolymer as templating agent coupled with sol-gel chemistry has been applied. Especially, a good-poor solvent pair induced phase separation process has been developed to guide the microphase separation behavior of the block copolymers. The amphiphilic block copolymers used include polystyrene-block-poly (ethylene oxide) (PS-b-PEO), poly (methyl methacrylate)-block-poly (ethylene oxide) (PMMA-b-PEO), and poly (ethylene oxide)-block-polystyrene-block-poly (ethylene oxide) (PEO-b-PS-b-PEO). The block copolymer undergoes a good-poor-solvent pair induced phase separation in a mixed solution of 1, 4-dioxane or N, N-dimethyl formamide (DMF), concentrated hydrochloric acid (HCl) and Titanium tetraisopropoxide (TTIP). Specifically, in the system of PS-b-PEO, a morphology phase diagram of the inorganic-copolymer composite films was mapped by adjusting the weight fractions among 1, 4-dioxane, HCl, and TTIP in solution. The amorphous TiO{sub 2} within the titania-block copolymer composite films was crystallized by calcination at temperatures above 400 C, where the organic block copolymer was simultaneously burned away. This strategy is further extended to other amphiphilic block copolymers of PMMA-b-PEO and PEO-b-PS-b-PEO, where the

  1. A review of quality surveillance projects on cosmetics in Taiwan

    Meng-Hsuan Chung

    2014-12-01

    Full Text Available The Food and Drug Administration in Taiwan is responsible for the quality regulation and control of cosmetics. In order to have a clear understanding of the trends in the product quality monitoring outcomes and the regulatory control measures over the past years, this study has put together the reports of nine cosmetic surveillance projects conducted between 1982 and 2012. The findings can be used as a reference in developing a more solid quality monitoring plan and management system for cosmetic products. Results show that permanent wave products, hair dye products, and phthalate esters in cosmetic products have the highest average noncompliance rates at 39.2%, 14.2%, and 11.2%, respectively. These are followed by the average noncompliance rates of mercury in products, sunscreen products, and microorganisms in products, at 8.5%, 7.1%, and 5.5%, respectively, and the remaining three projects averaging below 4.1%. Since 1997, when new standards were announced and assistance to manufacturers was reinforced, the noncompliance rates of permanent wave products decreased annually, until 2007, when it was fully qualified for the standards. Overall, the study showed that the noncompliance rates of permanent wave products and for levels of phthalate esters, mercury, and hydroquinone in cosmetic products have all decreased in the previous years. The results of surveillance projects conducted after 2005 revealed only one noncompliance sample with lead, arsenic, and cadmium, whereas the surveillance projects on permanent wave products and chloroform- and 1,4-dioxane-containing products revealed full compliance with regulation standards. However, the noncompliance rates for microorganisms in cosmetics and the ingredients in hair dye products and sunscreen products were still high. These high-risk products must be monitored. These surveillance projects are conducted to ensure the safety of cosmetics in the market.

  2. 3d-4f Metal-Organic Framework with Dual Luminescent Centers That Efficiently Discriminates the Isomer and Homologues of Small Organic Molecules.

    Zeng, Guang; Xing, Shanghua; Wang, Xiuru; Yang, Yulin; Ma, Dingxuan; Liang, Hongwei; Gao, Lu; Hua, Jia; Li, Guanghua; Shi, Zhan; Feng, Shouhua

    2016-02-01

    A 3d-4f luminescent metal-organic framework (MOF), [Tb2(Cu8I8)(C12H8NO2)6(H2O)4]·5C4H8O2 (4), and three analogues {[La2(Cu8I8)(C12H8NO2)6(C4H8O2)2(H2O)2]·3C4H8O2·2H2O (1), [Ce2(Cu8I8)(C12H8NO2)6(H2O)4]·5C4H8O2 (2), and [Eu2(Cu8I8)(C12H8NO2)6(H2O)4]·5C4H8O2 (3)}, were self-assembled from copper(I) halide clusters and lanthanide metal ions with an organic linker [3-(pyridin-4-yl)benzoic acid] under solvothermal conditions. Compound 4 with high quantum yield (Φ = 68%) exhibits reversible luminescence behavior, accompanying the removal and recovery of guest molecules (1,4-dioxane). Because of the unique porous structure and dual luminescent centers of compound 4, it can efficiently differentiate benzene series with different sizes and provide readouts in corresponding optical signals. Furthermore, it also can unambiguously discriminate the isomers, homologues, and other small molecules with similar structural motifs from one another. The luminescent color of the MOF sensor in different guest solvents has obvious changes that can be clearly distinguished by the naked eye. This multicolor luminescence originates from emissions of the dual luminescent centers, and the emissions have shifted, enhanced, weakened, or quenched to different degrees. PMID:26756250

  3. Thermodynamics of mixtures containing oxaalkanes. 6. Random mixing in ether + benzene, or + toluene systems

    Gonzalez, Juan Antonio, E-mail: jagl@termo.uva.es [G.E.T.E.F., Departamento de Fisica Aplicada, Facultad de Ciencias, Universidad de Valladolid, 47071 Valladolid (Spain); Garcia De La Fuente, Isaias; Cobos, Jose Carlos; Mozo, Ismael; Alonso, Ivan [G.E.T.E.F., Departamento de Fisica Aplicada, Facultad de Ciencias, Universidad de Valladolid, 47071 Valladolid (Spain)

    2011-02-20

    The Flory model has been applied to linear or cyclic ether + benzene, or +toluene mixtures. In addition, the relative variation of the molar excess enthalpy, H{sub m}{sup E}, along homologous series of the considered systems, has been discussed taking into account the contributions to H{sub m}{sup E} from the ether-ether, aromatic-aromatic and ether-aromatic interactions. It has been shown that in CH{sub 3}(CH{sub 2}){sub u-1}O(CH{sub 2}CH{sub 2}O){sub v}(CH{sub 2}){sub u-1}CH{sub 3} + benzene mixtures, the u increase (v fixed) leads to a weakening of interactions between unlike molecules, and that proximity effects also weaken this type of interactions. In contrast, the v increase (u fixed) or cyclization lead to stronger interactions between unlike molecules. From the application of the model, it is concluded that the random mixing hypothesis may be considered to be valid to a large extent for many of the investigated solutions. Erroneously, strong orientational effects are predicted for 1,3-dioxolane, or 1,4-dioxane + benzene systems, but this has been attributed to the model can not describe asymmetric H{sub m}{sup E} curves when the mixture compounds show close values for V{sub i} (molar volume) and for V{sub i}{sup *} (reduction parameter for volume). Previous calculations on the basis of the Kirkwood-Buff integrals formalism confirm that the mixture structure is close to random mixing. Flory results on the excess molar volumes have been discussed taking into account the so-called curvature and P* contributions to this excess function.

  4. Preparation and Characterization of a Novel Smart Polymeric Hydrogel for Drug Delivery of Insulin

    Soodabeh Davaran

    2011-08-01

    Full Text Available Introduction: Over the past years, temperature and pH-sensitive hydrogels was developed as suitable carriers for drug delivery. In this study temperature and pH-sensitive hydrogels was designed for an oral insulin delivery modeling. Methods: NIPAAm-MAA -HEM copolymers were synthesized by radical chain reaction with 86:4:10 (5% w/v ratios respectively. Reaction was carried out in 1,4-Dioxane under Nitrogen gas-flow. The copolymers were characterized with FT-IR, 1H-NMR and DSC. Copolymers were loaded with regular insulin by modified double emulsion method with ratio of 1:10. Release study carried out in two different pH (pH=2 and 7.4 for stomach and intestine simulation respectively at 37ºC. For each pH, a 5 mL suspension of the insulin containing hydrogel was taken in to a cellulose acetate dialysis membrane, and the dialysis membrane was allowed to float in a beaker containing 15 mL of buffer solution. The beakers were placed in a shaker incubator maintained at 37ºC. Phosphate buffer (0.1 M, pH 3/ acetonitrile (60/40 was used as the mobile phase in HPLC assay. Results: Yield of reaction was 86% with an optimum Lower Critical Solution Temperature point (30ºC. In-vitro studies showed a control release behavior via pH changes which the amount of insulin releases was 80% and 20% at pH=2 and 7.4 respectively. Conclusion: Results showed that by optimizing polymerization and loading method we could achieve a suitable nano system for oral delivery of insulin.

  5. Protective Effect of Nigella Sativa Black Seed Oil And Freshly Crushed Seeds In Rats During Tumour Induction And Radiotherapy

    The present study was conducted to evaluate the potency of Nigella sativa freshly crushed seeds (0.42 g/ kg body weight) or oil (2.5 ml/kg body weight) for preventing tumor induction through exposure of rats to a common pollutant (1,4- Dioxane) as a promoter under condition of the presence of an initiator (N-nitrosodiethylamine). The antitumor effect was evaluated alone or in combination with low doses of irradiation as a route of cancer treatment. Female Swiss albino rats were administrated orally twice weekly with Nigella sativa before and during exposure of rats to the carcinogenic compounds. Animals were exposed to 3 doses of radiation (3 Gy/ dose) day after day 2 weeks before the end of the experiment. The animals were scarified after one week of radiation. Homocysteine,'glutathione, lipid peroxide, GGT activity, nitric oxide, total protein, albumin and bilirubin levels were estimated in blood after 7 and 12 months from the start of the experiment. Rats injected with the carcinogenic compounds showed marked elevation in homocysteine, GGT activity, nitric oxide, bilirubin and lipid peroxide levels accompanied by a significant decrease in glutathione, total proteins and albumin levels. Pretreatment with Nigella sativa alone or combined with γ- irradiation potentially reversed the investigated parameters. Moreover, Nigella sativa significantly suppressed the growth of the tumor and efficiently produced synergistic effect with γ-irradiation. Therefore, Nigella sativa may be a good candidate to prevent tumor induction and so, it is advicable to use freshly crushed seeds during irradiation treatment in cancer patients as they gave more effective protection than the oil extract.

  6. Transport of Indium, Gallium and Thallium Metal Ions Through Chromatographic Fiber Supported Solid Membrane in Acetylacetone Containing Mixed Solvents

    Abaji Gaikwad

    2011-01-01

    The transport of metal ions of indium, gallium and thallium from source solution to receiving phase through the chromatographic fiber supported solid membrane in the acetylacetone (HAA) containing mixed solvent system has been explored. The fibers supported solid membranes were prepared with chemical synthesis from cellulose fibers and citric acid with the carboxylic acid ion exchange groups introduced. The experimental variables, such as concentration of metal ions (10^-2 to 10^-4 mol.L^-1) in the source solution, mixed solvent composition [for exampl, e, acetylacetone, (2,4-pentanedione), (HAA) 20% (by volume), 1,4-dioxane 10% to 60% and HC1 0.25 to 2 mol.L^-1] in the receiving phase and stirring speed (50-130 r.min ) of the bulk source and receiving phase, were explored. The efficiency of mixed solvents for the transport of metal ions from the source to receiving phase through the fiber supported solid membrane was evaluated. The combined ion exchange solvent extraction (CIESE) was observed effective for the selective transport of thallium, indium and gallium metal ions through fiber supported solid membrane in mixed solvents. The oxonium salt formation in the receiving phase enhances thallium, indium and gallium metal ion transport through solid membrane phase. The selective transport of thallium metal ions from source phase was observed from indium and gallium metal ions in the presence of hydrochloric acid in organic solvents in receiving phase. The separation of thallium metal ions from the binary mixtures of Be(II), Ti(IV), AI(III) Ca(II), Mg(II), K (I), La(III) and Y(III) was carried out in the mixed solvent system using cellulose fiber supported solid membrane.

  7. Study on the decomposition mechanism of alkyl carbonate on lithium metal by pyrolysis-gas chromatography-mass spectroscopy

    Mogi, Ryo; Inaba, Minoru; Iriyama, Yasutoshi; Abe, Takeshi; Ogumi, Zempachi

    The surface films formed on deposited lithium in electrolyte solutions based on ethylene carbonate (EC), diethyl carbonate (DEC), and dimethyl carbonate (DMC) were analyzed by pyrolysis-gas chromatography-mass spectroscopy (Py-GC-MS). In 1 M LiClO 4/EC, the main component of the surface film was easily hydrolyzed to give ethylene glycol after exposure to air, and hence was considered to have a chemical structure of ROCH 2CH 2OR', of which OR and OR' are OLi or OCO 2Li. Ethylene oxide, acetaldehyde, and 1,4-dioxane were detected in decomposition products, and they were considered to have been formed by pyrolysis of ROCH 2CH 2OR' in the pyrolyzer. The presence of ethanol in decomposition products confirmed that ring cleavage at the CH 2O bonds of EC occurs by one electron reduction. In addition, the presence of methanol implied the cleavage of the CC bond of EC upon reduction. From the surface films formed in 1 M LiClO 4/DEC and /DMC, ethanol and methanol, respectively, were detected, which suggested that corresponding lithium alkoxides and/or lithium alkyl carbonates were the main components. In 1 M LiClO 4/EC+DEC (1:1), EC dominantly decomposed to form the surface film. The surface film formed in 1 M LiPF 6/EC+DEC (1:1) contained a much smaller amount of organic compounds.

  8. Micellization behaviour and thermodynamic parameters of 12-2-12 gemini surfactant in (water + organic solvent) mixtures

    Batigoec, Cigdem [Department of Chemistry, Faculty of Sciences, Trakya University, 22030 Edirne (Turkey); Akbas, Halide, E-mail: hakbas34@yahoo.com [Department of Chemistry, Faculty of Sciences, Trakya University, 22030 Edirne (Turkey); Boz, Mesut [Department of Chemistry, Faculty of Sciences, Trakya University, 22030 Edirne (Turkey)

    2011-09-15

    Highlights: > The cmc and {alpha} values of surfactant increased with increasing solvent content and temperature. > The values of ({Delta}G{sub m}{sup 0}) are negative in all cases for the micelle formation becomes less favourable. > The values of negative enthalpy indicate importance of the London dispersion forces for the micellization. > The positive entropy is due to a contribution supplied from the solvent. - Abstract: The effect of organic solvents on micellization behaviour and thermodynamic parameters of a cationic gemini (dimeric) surfactant, C{sub 12}H{sub 25}(CH{sub 3}){sub 2}N{sup +}-(CH{sub 2}){sub 2}-N{sup +}(CH{sub 3}){sub 2}C{sub 12}H{sub 25}.2Br{sup -}, (12-2-12) was studied in aqueous solutions over the range of T = (293.15 to 323.15) K using the conductometric technique. Ethylene glycol (EG), dimethylsulfoxide (DMSO) and 1,4-dioxan (DO) were used as organic solvents with three different contents. The critical micelle concentration (cmc) and the degree of counter ion dissociation ({alpha}) of micelles in the water and in the (water + organic solvent) mixtures including 10%, 20%, and 30% solvent contents were determined. The standard Gibbs free energy ({Delta}G{sub m}{sup 0}), enthalpy ({Delta}H{sub m}{sup 0}) and entropy ({Delta}S{sub m}{sup 0}) of micellization were estimated from the temperature dependence of the cmc values. It was observed that the critical micelle concentration of the gemini surfactant and the degree of counter ion dissociation of the micelle increased as the volume percentage of organic solvent, and temperature increased. The standard Gibbs free energy of micellization was found to be less negative with the increase in the organic solvent content and temperature.

  9. Solvent dependence of Stokes shift for organic solute-solvent systems: A comparative study by spectroscopy and reference interaction-site model-self-consistent-field theory

    Nishiyama, Katsura; Watanabe, Yasuhiro; Yoshida, Norio; Hirata, Fumio

    2013-09-01

    The Stokes shift magnitudes for coumarin 153 (C153) in 13 organic solvents with various polarities have been determined by means of steady-state spectroscopy and reference interaction-site model-self-consistent-field (RISM-SCF) theory. RISM-SCF calculations have reproduced experimental results fairly well, including individual solvent characteristics. It is empirically known that in some solvents, larger Stokes shift magnitudes are detected than anticipated on the basis of the solvent relative permittivity, ɛr. In practice, 1,4-dioxane (ɛr = 2.21) provides almost identical Stokes shift magnitudes to that of tetrahydrofuran (THF, ɛr = 7.58), for C153 and other typical organic solutes. In this work, RISM-SCF theory has been used to estimate the energetics of C153-solvent systems involved in the absorption and fluorescence processes. The Stokes shift magnitudes estimated by RISM-SCF theory are ˜5 kJ mol-1 (400 cm-1) less than those determined by spectroscopy; however, the results obtained are still adequate for dipole moment comparisons, in a qualitative sense. We have also calculated the solute-solvent site-site radial distributions by this theory. It is shown that solvation structures with respect to the C-O-C framework, which is common to dioxane and THF, in the near vicinity (˜0.4 nm) of specific solute sites can largely account for their similar Stokes shift magnitudes. In previous works, such solute-solvent short-range interactions have been explained in terms of the higher-order multipole moments of the solvents. Our present study shows that along with the short-range interactions that contribute most significantly to the energetics, long-range electrostatic interactions are also important. Such long-range interactions are effective up to 2 nm from the solute site, as in the case of a typical polar solvent, acetonitrile.

  10. A Convenient Approach to Heterocyclic Building Blocks: Synthesis of Novel Ring Systems Containing a [5,6]Pyrano[2,3-c]pyrazol-4(1H-one Moiety

    Wolfgang Holzer

    2007-01-01

    Full Text Available Starting from commercially available educts, a straightforward synthetic route to new heterocyclic building blocks is exemplified with the one- or two-step synthesis of tri-, tetra-, or pentacyclic ring systems. Representatives of the following novel ring systems are prepared from 3-methyl-1-phenyl-2-pyrazolin-5-one and the corresponding o-halo-arenecarbonyl chloride using calcium hydroxide in refluxing 1,4-dioxane: pyrimidino[4',5':5,6]pyrano[2,3-c]pyrazol-4(1H-one, thieno[3',2':5,6]pyrano[2,3c]pyrazol- 4-(1H-one, thieno[3',4':5,6]pyrano[2,3-c]pyrazol-4(1H-one, thieno[3'',2'':4',5']thieno[2',3':5,6]-pyrano[2,3-c]pyrazol-4(1H-one, [1,3]dioxolo[5',6'][1]benzothieno[2',3':5,6]pyrano-[2,3-c]- pyrazol-4(1H-one, pyridazino[4',3':5,6]pyrano[2,3-c]pyrazol-4(1H-one and pyrazolo-[4'',3'':5',6']pyrido[3',4':5,6]pyrano[2,3-c]pyrazol-4(1H-one. While the latter two ring systems are directly obtained due to a spontaneous intramolecular substitution reaction, in the other reactions uncyclised 4-aroylpyrazol-5-ols are produced, which are cyclised into the target heterocycles in a subsequent synthetic step (i.e. treatment with NaH in DMF. Detailed NMR spectroscopic investigations (1H-, 13C-, 15N- with the obtained compounds were undertaken to unambiguously prove the new structures.

  11. Combined use of titration calorimetry and spectrofluorimetry for the screening of the acidity of solid catalysts in different liquids

    Gervasini, Antonella, E-mail: antonella.gervasini@unimi.it [Dipartimento di Chimica, Università degli Studi di Milano, via Camillo Golgi, 19, 20133 Milano (Italy); Auroux, Aline, E-mail: aline.auroux@ircelyon.univ-lyon1.fr [Université Lyon 1, CNRS, UMR 5256, Institut de Recherches sur la Catalyse et l‘Environnement de Lyon (IRCELYON), 2 Avenue A. Einstein, 69626 Villeurbanne (France)

    2013-09-10

    Graphical abstract: Measurements of acidity of oxides of catalytic importance in various liquids open the possibility to know their effective acidity, which is related with their activity in liquid-heterogeneous catalysis. Titration-calorimetry alone or in connection with spectrofluorimetry is efficient for this scope. - Highlights: • Measurements of acidity of oxides of catalytic importance in various liquids. • Titration-calorimetry alone or in connection with spectrofluorimetry is efficient for this scope. • Effective acidities are expressed by given sample in various liquids. • Nb-containing samples are able to maintain acidity in protic liquids. - Abstract: The effective acid and base surface properties of selected acidic and basic samples of catalytic interest (alumina, titania, zirconia, silica–alumina, niobium oxide, niobium phosphate, boron nitride, and hydrotalcite) were measured by titration with basic and acidic molecular probes (aniline, 2-phenylethylamine, and phenol) in various liquids (cyclohexane, 1,4-dioxane, isopropanol, n-decane, and toluene) with different polar and protic characteristics. The combined use of a reaction calorimeter and a spectrofluorimeter has been performed. The set-up of the coupled technique and the most interesting results are shown here. The study confirmed that the acid–base properties of solids are deeply affected by the nature and properties of the liquid surrounding the samples. Few oxides are able to maintain their surface acidity in highly polar and protic solvents, in particular whose containing niobium. In general, the solvating and coordinative ability of the most polar and protic liquids caused remarkable loss of acidity/basicity of the oxide surfaces.

  12. Thermodynamics of mixtures containing oxaalkanes. 6. Random mixing in ether + benzene, or + toluene systems

    The Flory model has been applied to linear or cyclic ether + benzene, or +toluene mixtures. In addition, the relative variation of the molar excess enthalpy, HmE, along homologous series of the considered systems, has been discussed taking into account the contributions to HmE from the ether-ether, aromatic-aromatic and ether-aromatic interactions. It has been shown that in CH3(CH2)u-1O(CH2CH2O)v(CH2)u-1CH3 + benzene mixtures, the u increase (v fixed) leads to a weakening of interactions between unlike molecules, and that proximity effects also weaken this type of interactions. In contrast, the v increase (u fixed) or cyclization lead to stronger interactions between unlike molecules. From the application of the model, it is concluded that the random mixing hypothesis may be considered to be valid to a large extent for many of the investigated solutions. Erroneously, strong orientational effects are predicted for 1,3-dioxolane, or 1,4-dioxane + benzene systems, but this has been attributed to the model can not describe asymmetric HmE curves when the mixture compounds show close values for Vi (molar volume) and for Vi* (reduction parameter for volume). Previous calculations on the basis of the Kirkwood-Buff integrals formalism confirm that the mixture structure is close to random mixing. Flory results on the excess molar volumes have been discussed taking into account the so-called curvature and P* contributions to this excess function.

  13. A study on fluorescence quenching of LD-425 by aromatic amines in 1,4-dioxane–acetonitrile mixtures

    The fluorescence quenching of 4-methyl-7-(4-morpholiny)-2H-pyrano[2,3-b]pyridin-2-one (LD-425) by aromatic amines aniline (AN), dimethyl aniline (DMAN) and diethyl aniline (DEAN) in solvent mixtures of 1,4-dioxane and acetonitrile has been studied at room temperature by steady-state and time-resolved methods. The positive deviation from linearity has been observed in the Stern–Volmer (S–V) plots. Various quenching rate parameters have been determined using the extended S–V equation and are found to be dependent on solvent polarity. The quenching ability of amines increases with increase in their ionization energies. Further, with the use of the sphere of action static quenching model and finite sink approximation model, it is concluded that the bimolecular quenching reactions are due to the presence of both dynamic and static quenching processes. - Graphical abstract: 4-methyl-7-(4-morpholiny)-2H-pyrano[2,3-b]pyridin-2-one (LD-425) Highlights: ► S–V plots of LD-425 show positive deviation in DIO–ACN solvent mixtures with all aromatic amines. ► r>R and kq>4πN′R′D indicate that quenching reactions are due to static quenching with diffusion limited. ► The time resolved measurements indicate the presence of the dynamic quenching process. ► The increase in kq with dielectric constant of solvents indicates the charge transfer character. ► Quenching efficiency increasing with amines ionization energies shows electron transfer nature.

  14. Comparison of UVC/S2O8(2-) with UVC/H2O2 in terms of efficiency and cost for the removal of micropollutants from groundwater.

    Antoniou, Maria G; Andersen, Henrik R

    2015-01-01

    This study compared the UVC/S2O8(2-) system with the more commonly used AOP in water industry, UVC/H2O2, and examined whether the first one can be an economically feasible alternative technology. Atrazine and 4 volatile compounds (methyl tert-butyl ether, cis-dichlorethen, 1,4-dioxane and 1,1,1-trichloroethane) were chosen as model contaminants because they exhibit different susceptibility to UVC photolysis and AOPs. A collimated beam apparatus was utilized for the majority of the experiments (controlled environment, without mass transfer phenomena), while selected experiments were performed in a flow-through reactor to simulate industrial applications. Initial experiments on the activation of oxidants with a LP lamp indicated that S2O8(2-) is photolysed about 2.3 times faster than H2O2 and that the applied treatment times were not sufficient to utilize the majority of the oxidant. The effect of oxidants' concentrations were tested with atrazine alone and in the micropollutants' mixture and it was decided to use 11.8 mg L(-1) S2O8(2-) and 14.9 mg L(-1) H2O2 for further testing since is closer to industrial applications and to minimize the residual oxidant concentration. Changes of the matrix composition of the treated water were investigated with the addition of chloride, bicarbonate and humic acids at concentrations relevant to a well-water-sample, the results showed that the system least affected was UVC/H2O2. Only when bicarbonate was used, UVC/S2O8(2-) performed better. Overall, testing these systems with the mixture of micropollutants gave better insights to their efficiency than atrazine alone and UVC/S2O8(2-) is recommended for selective oxidation of challenging matrices. PMID:24745559

  15. A Simple Spectrophotometric Method for the Determination of Copper in Some Real, Environmental, Biological, Food and Soil Samples Using Salicylaldehyde Benzoyl Hydrazone

    M. Jamaluddin Ahmed

    2012-06-01

    Full Text Available A very simple, ultra-sensitive, highly selective and non-extractive spectrophotometric method for the determination of trace amounts copper(II has been developed. Salicylaldehy debenzoyl hydrazone (SAL-BH has been proposed as a new analytical reagent for the direct non-extractive spectrophotometric determination of copper(II. SAL-BH reacts with copper in a slightly acidic (0.0001-0.005 M H2SO4 in 40% 1,4-dioxane media with copper(II to give a highly absorbent greenish yellow chelate with a molar ratio 1:1(CuII: SAL-BH The reaction is instantaneous and the maximum absorption was obtained at 404 nm and remains stable for 72 h. The average molar absorptivity and Sandell’s sensitivity were found to be 1.4×105 L mol-1 cm-1 and 5.0 ng cm-2 of copper(II, respectively. Linear calibration graphs were obtained for 0.01 – 18 mg L-1 of CuII. The detection limit and quantification limit of the reaction system were found to be 1 ng mL-1 and 10 µg L-1, respectively. A large excess of over 50 cations, anions and complexing agents (e.g., tartrate, oxalate, citrate, phosphate, thiocyanate etc. do not interfere in the determination. The method is highly selective for copper and was successfully used for the determination of copper in several standard reference materials (steels and alloys as well as in some environmental waters (portable and polluted, biological (human blood and urine, food and soil samples and solutions containing both copper(I and copper(II as well as some complex synthetic mixtures. The results of the proposed method for biological and food samples were comparable with AAS and were found to be in good agreement. The method has high precision and accuracy (s = ± 0.01 for 0.5 mg L-1.

  16. The fate of organic micropollutants during long-term/long-distance river bank filtration.

    Hamann, Enrico; Stuyfzand, Pieter J; Greskowiak, Janek; Timmer, Harrie; Massmann, Gudrun

    2016-03-01

    The fate of organic micropollutants during long-term/long-distance river bank filtration (RBF) at a temporal scale of several years was investigated along a row of monitoring wells perpendicular to the Lek River (the Netherlands). Out of 247 compounds, which were irregularly analyzed in the period 1999-2013, only 15 were detected in both the river and river bank observation wells. Out of these, 10 compounds (1,4-dioxan, 1,5-naphthalene disulfonate (1,5-NDS), 2-amino-1,5-NDS, 3-amino-1,5-NDS, AOX, carbamazepine, EDTA, MTBE, toluene and triphenylphosphine oxide) showed fully persistent behavior (showing no concentration decrease at all), even after 3.6 years transit time. The remaining 5 compounds (1,3,5-naphthalene trisulfonate (1,3,5-NTS), 1,3,6-NTS, diglyme, iopamidol, triglyme) were partially removed. Their reactive transport parameters (removal rate constants/half-lives, retardation coefficients) were inferred from numerical modeling. In addition, maximum half-lives for 14 of the fully removed compounds, for which the data availability was sufficient to deduce 100% removal during sub-surface passage, were approximated based on travel times to the nearest well. The study is one of very few reporting on the long-term field-scale behavior of organic micropollutants. It highlights the efficiency of RBF for water quality improvement as a pre-treatment step for drinking water production. However, it also shows the very persistent behavior of various compounds in groundwater. PMID:26766391

  17. Covalent immobilization of glucose oxidase within organic media%葡萄糖氧化酶的有机相共价固定化

    周涛; 朱雄军; 苏建华; 姚冬生; 刘大岭

    2012-01-01

    将葡萄糖氧化酶(GOD)在最适pH条件下冻干后,以戊二醛活化的壳聚糖为载体,分别在传统水相和1,4-二氧六环、乙醚、乙醇三种不同的有机相中进行共价固定化.通过比较水相固定化酶和有机相固定化酶的酶比活力、酶学性质及酶动力学参数,考察酶在有机相中的刚性特质对酶在共价固定化过程中保持酶活力的影响.结果表明,戊二醛浓度为0.1%、加酶量为80 mg/1 g载体、含水1.6%的1,4-二氧六环有机相固定化GOD与水相共价固定化GOD相比,酶比活力提高2.9倍,有效酶活回收率提高3倍;在连续使用7次后,1,4-二氧六环有机相固定化GOD的酶活力仍为相应水相固定化酶的3倍.在酶动力学参数方面,不论是表观米氏常数,最大反应速度还是转换数,1,4-二氧六环有机相固定化的GOD (Km app=5.63 mmol/L,Vmax=1.70 μmol/(min·mg GOD),Kcat=0.304 s-1)都优于水相共价固定化GOD (Km app=7.33 mmol/L,V max=1.02 μmol/(min·mg GOD),Kcat=0.221 s-1).因此,相比于传统水相,GOD在合适的有机相中进行共价固定化可以获得具有更高酶活力和更优催化性质的固定化酶.该发现可能为酶蛋白在共价固定化时因构象改变而丢失生物活性的问题提供解决途径.%Activity losing during the covalent immobilization of enzyme is a serious problem. Here we studied organic phase immobilization by using glucose oxidase (GOD) as a model. After lyophilized at optimum pH, GOD is covalently immobilized onto glutaraldhy de-activated chitosan microsphere carrier under the condition of water, 1, 4-dioxane, ether and ethanol separately. The special activities, enzyme characterization and kinetic parameters are determined. Results show that all of the organic phase immobilized GODs have higher special activities and larger Kcat than that of aqueous phase. Under the conditions of 0.1% of glutaraldehyde,1.6% moisture content with 80 mg of GOD added to per gram of carrier, 2

  18. Solvent-controlled synthesis of tetranuclear cage-like copper(II) silsesquioxanes. Remarkable features of the cage structures and their high catalytic activity in oxidation with peroxides.

    Dronova, Marina S; Bilyachenko, Alexey N; Yalymov, Alexey I; Kozlov, Yuriy N; Shul'pina, Lidia S; Korlyukov, Alexander A; Arkhipov, Dmitry E; Levitsky, Mikhail M; Shubina, Elena S; Shul'pin, Georgiy B

    2014-01-14

    Two principally different in their molecular architecture isomeric tetranuclear copper(ii) silsesquioxanes, "Globule"-like compound [(PhSiO1.5)12(CuO)4(NaO0.5)4] (1) and "Sandwich"-like derivative [(PhSiO1.5)6(CuO)4(NaO0.5)4(PhSiO1.5)6] (2), were synthesized by the partial cleavage of polymeric copper(ii) silsesquioxane [(PhSiO1.5)2(CuO)]n by tetraphenylcyclotetrasiloxanolate. The route leading to the formation of either 1 or 2 entirely depends on the nature and composition of the solvent used for this reaction. Thus, the process in an ethanol-1-butanol solution gives compound 1. When a 1,4-dioxane-methanol mixture was used, compound 2 was prepared. The structures and unusual crystal packing of the cages were confirmed by the X-ray studies. It has been found that the reaction of benzene with H2O2 in acetonitrile solution at 50 °C catalyzed by 1 requires addition of trifluoroacetic acid (TFA) in low concentration and gives phenol with a turnover number (TON) of 250 after 3 h. The initial reaction rate W0 linearly depends on the concentration of catalyst 2. The oxidation of 1-phenylethanol to acetophenone with hydrogen peroxide catalyzed by complex 1 in the presence of TFA is not efficient. In contrast, 1 exhibited excellent activity in the oxidation with tert-butyl hydroperoxide (TBHP) in the absence of any acid (the yield of acetophenone was close to the quantitative, TON attained 475 after 2 h). A kinetic study of this reaction led to the conclusion that the process occurs with the participation of radicals tert-BuO˙ produced in the Cu-promoted decomposition of TBHP. The mode of dependence of W0 on the initial concentration of TBHP indicates the formation of an intermediate adduct between the catalyst 1 and TBHP (characterized by the equilibrium constant K1≈ 2 M(-1) for the conditions of conducted experiments) followed by subsequent decomposition of the adduct (k2≈ 0.2 s(-1)) to generate an intermediate species tert-BuO˙ which induces the alcohol oxidation

  19. 超声辅助或无溶剂Claisen-Schmidt反应合成含胡椒环的吲哚查尔酮%A facile synthesis of 1,3-benzodioxole-bearing indole-based chalcone via ultrasound-assisted or solvent-free Claisen-Schmidt condensation reaction

    李阳

    2014-01-01

    A structurally novel 1,3-benzodioxole-bearing indole-based chalcone,namely(E)-3-(benzo[d][1,3]dioxol-5-yl)-1-(2-chloro-1-(4-chlorobenzyl)-1H-indol-3-yl) prop-2-en-1-one(3) was synthesized,involving the ultrasound-assisted or solvent-free Claisen-Schmidt condensation reaction of 3-acetyl-2-chloro-1-(4-chlorobenzyl) indole and piperonaldehyde. The ultrasound-assisted Claisen-Schmidt condensation reaction was carried out using 1,4-dioxane as solvent and KOH as catalyst at room temperature to give the product 3 in 78%yield. Alternatively,the reaction could also be conducted under solvent-free condition by physical grinding in a mortar and pestle to obtain 3 in comparable yield of 75%. The two procedures offered easy access to 1,3-benzodioxole-bearing indole-based chalcone in short reaction time and good yield under mild conditions.%3-乙酰基-2-氯-1-(4-氯苄基)吲哚与胡椒醛通过超声辅助或无溶剂的Claisen-Schmidt缩合反应首次合成含胡椒环的吲哚查尔酮,即(E)-3-(5-胡椒基)-1-(2-氯-1-(4-氯苄基)-1H-3-吲哚查尔酮(3)。超声辅助的合成方法使用5%KOH作为催化剂,1,4-二氧六环作为溶剂,以78%的收率得到产品3。另外,这一 Claisen-Schmidt反应也可以在无溶剂研磨条件下进行,同样也以类似的收率获得产品3(75%)。这两种方法具有操作简便、反应条件温和、收率高等优点。

  20. Cefazolin-containing poly(ε-caprolactone sponge pad to reduce pin tract infection rate in rabbits

    Hirotaka Mutsuzaki

    2014-04-01

    Full Text Available In our previous study, a fibroblast growth factor-2 (FGF-2–apatite composite layer coated on titanium screws effectively prevented pin tract infection in rabbits because of enhanced wound healing; however, the FGF-2–apatite composite layers did not completely prevent pin tract infection. Thus, we recently developed a poly(ε-caprolactone (PCL sponge pad embedded with cefazolin sodium (+CEZ, which has a fast-acting bactericidal effect. The pad is placed on the skin around the screws. The purpose of this study was to determine the anti-infective efficacy of the +CEZ pad on the pin–skin interface of the FGF-2–apatite-coated titanium screws. The +CEZ pads were prepared by mixing PCL and CEZ in 1,4-dioxane, followed by freeze-drying and compaction. They were analyzed regarding their surface structure, in vitro CEZ release profile, and bactericidal activity. The FGF-2–apatite-coated screws were implanted percutaneously in bilateral rabbit proximal tibial metaphyses—with and without the +CEZ pad—for 4 weeks (n = 20. The + CEZ pads consisted of a porous matrix of PCL in which CEZ was embedded. The CEZ-release profile showed an initial burst on Day 1 and a sustained release lasting for 30 days. The +CEZ pad retained its bactericidal activity against Staphylococcus aureus after preincubation on an agar plate for 7 days. Based on visual inspection, the pin tract infection rate was successfully reduced from 72.2% to 15.0% with the +CEZ pad (p < 0.05, which reduced the bacterial count, especially S. aureus (p < 0.05. The histological inflammation rate of the soft tissues was also significantly lower with the +CEZ pad than without it (p < 0.05. The pin tract infection rate was reduced to one-fifth with the +CEZ pad. Using it as described improves infection resistance during percutaneous implantation.

  1. 四正丁基溴化铵催化的氮杂环丙烷与水合羧酸铜的开环反应%Efficient ring-opening reactions of N-tosylaziridines with hydrous cupric carboxylate mediated by tetra-n-butyl ammonium bromide

    张万轩; 周洁; 黄巍; 苏莉; 汤从国

    2012-01-01

    β-amino alcohol esters could be obtained from the reactions of aziridines with hydrated cupric acetate which were catalysed by tetran-butyl ammonium bromide. Firstly, condition was optimized, such as using different hydration carboxylic acid salts, solvents, reaction temperatures, catalyst of quaternary ammonium salts and the ratios of reaction raw materials to the reaction. 1, 4-dioxane was the best solvent and the preferential molar ratio of aziridine, hydrated cupric acetate and tetrabutyl ammonium bromide was 1 : 0. 6:0. 2. Finally, we expanded the substrate of aziridine and hydrated cupric carboxylates for an excellent yields ( 85%—99%) in a short time. The regioselectivities were 83%—95% for the major products. In the case of cycloalkyl aziridines, the stereochemistry of the ring product was found to be trans-form. Alkyl N-tosyl aziridines and aryl N-tosyl aziridines both mainly underwent cleavage at the terminal carbon atom. A new convenient method for the preparation of β-amino alcohol esters was developed and the role of cation Cu2+ was discussed.%氮杂环丙烷与水合羧酸铜在溴化四丁基铵的催化下可以合成β-胺基醇酯,首先通过条件优化,分别对不同水合羧酸盐、溶剂、反应温度、季铵盐催化剂、反应物料配比对该反应的影响进行研究,得到最优条件:溶剂为1,4-二氧六环,反应条件为回流,氮杂环丙烷、一水乙酸铜、四正丁基溴化铵的摩尔比为1∶0.6∶0.2.然后在此条件下拓展不同反应底物,反应时间短,产物的产率高(85%~99%),产物的区域选择性也高(83%~95%).这种方法对于N-Ts活化的环状氮杂环丙烷,开环产物的立体结构为反式;对芳基和烷基取代的N-Ts活化的氮杂环丙烷,主要开环产物为端位开环产物.对反应条件和Cu2+的作用进行了讨论.

  2. A simple spectrophotometric method for the determination of copper in some real, environmental, biological, food and soil samples using salicylaldehyde benzoyl hydrazone

    A very simple, ultra-sensitive, highly selective and non-extractive spectrophotometric method for the determination of trace amounts copper (II) has been developed. Salicylaldehyde debenzoyl hydrazone (SAL-BH) has been proposed as a new analytical reagent for the direct non-extractive spectrophotometric determination of copper (II). SAL-BH reacts with copper in a slightly acidic (0.0001-0.005 M H/sub 2/SO/sub 4/) in 40% 1,4-dioxane media with copper(lI) to give a highly absorbent greenish yellow chelate with a molar ratio 1:1(CuII: SAL-BH) The reaction is instantaneous and the maximum absorption was obtained at 404 nffi and remains stable for 72 h. The average molar absorptivity and Sandell's sensitivity were found to be 1.4x105 L mol-I cm/sup -1/ and 5.0 ng cm-2 of copper (II), respectively. Linear calibration graphs were obtained for 0.01 -18 mg L-1 of C/sup 11/. The detection limit and quantification limit of the reaction system were found to be 1 ng mL/sup -1/ and 10 micro.g L/sup -1/, respectively. A large excess of over 50 cations, anions and complexing agents (e.g., tartrate, oxalate, citrate, phosphate, thiocyanate etc.) do not interfere in the determination. The method is highly selective for copper and was successfully used for the determination of copper in several standard reference materials (steels and alloys) as well as in some environmental waters (portable and polluted), biological (human blood and urine), food and soil samples and solutions containing both copper (I) and copper( II) as well as some complex synthetic mixtures. The results of the proposed method for biological and food samples were comparable with AAS and were found to be in good agreement. The method has high precision and accuracy (s = t 0.01 for 0.5 mgL/sup -1/). (author)

  3. Theoretical study of the reaction kinetics of atomic bromine with tetrahydropyran

    Giri, Binod

    2015-02-12

    A detailed theoretical analysis of the reaction of atomic bromine with tetrahydropyran (THP, C5H10O) was performed using several ab initio methods and statistical rate theory calculations. Initial geometries of all species involved in the potential energy surface of the title reaction were obtained at the B3LYP/cc-pVTZ level of theory. These molecular geometries were reoptimized using three different meta-generalized gradient approximation (meta-GGA) functionals. Single-point energies of the stationary points were obtained by employing the coupled-cluster with single and double excitations (CCSD) and fourth-order Møller-Plesset (MP4 SDQ) levels of theory. The computed CCSD and MP4(SDQ) energies for optimized structures at various DFT functionals were found to be consistent within 2 kJ mol-1. For a more accurate energetic description, single-point calculations at the CCSD(T)/CBS level of theory were performed for the minimum structures and transition states optimized at the B3LYP/cc-pVTZ level of theory. Similar to other ether + Br reactions, it was found that the tetrahydropyran + Br reaction proceeds in an overall endothermic addition-elimination mechanism via a number of intermediates. However, the reactivity of various ethers with atomic bromine was found to vary substantially. In contrast with the 1,4-dioxane + Br reaction, the chair form of the addition complex (c-C5H10O-Br) for THP + Br does not need to undergo ring inversion to form a boat conformer (b-C4H8O2-Br) before the intramolecular H-shift can occur to eventually release HBr. Instead, a direct, yet more favorable route was mapped out on the potential energy surface of the THP + Br reaction. The rate coefficients for all relevant steps involved in the reaction mechanism were computed using the energetics of coupled cluster calculations. On the basis of the results of the CCSD(T)/CBS//B3LYP/cc-pVTZ level of theory, the calculated overall rate coefficients can be expressed as kov.,calc.(T) = 4.60 × 10

  4. The role of water in solvating the hydrogen-bonding center of 2-(2‧-hydroxyphenyl)benzoxazole

    Abou-Zied, Osama K.

    2007-08-01

    2-(2'-Hydroxyphenyl)benzoxazole (HBO) has been useful as a probe to study tautomerization in DNA. In order to clarify the role of water in solvating the hydrogen-bonding center of HBO, we examine here the effect of water on the ground- and excited-state properties of HBO by steady state absorption and fluorescence spectroscopy, and by ab initio calculations. The study was carried out in solvents of varying polarity and hydrogen-bonding capability and in binary mixtures of 1,4-dioxane/water and methanol/water. HBO exists in three equilibrium structures in its ground state which are solvent-dependent, solvated and closed syn-enols and anti-enol. Only closed syn-enol is able to undergo tautomerization in the excited state to form syn-keto tautomer. Fluorescence due to solvated HBO was observed at 370 nm. The intensity change in the fluorescence peak at 370 nm as a function of water content in the binary solvents was quantitatively analyzed. Two water molecules were found to solvate the hydrogen-bonding center of the syn-enol tautomer in the ground state. The ground-state structures of the syn-enol tautomer with one to four water molecules were calculated by performing ab initio calculations at the MP2/6-31G(d) level and it was found that only two water molecules interact with the hydrogen-bonding center of HBO, confirming the above results. As water content increased in the binary mixtures, the keto tautomer fluorescence shifted to the blue and increased in intensity. This change was attributed to the formation of an anion species in the excited state which is stabilized in high polar binary mixtures. This result was confirmed by measuring the fluorescence in aqueous solution of pH 13. At high water contents, the behavior of the binary mixtures approaches that of pure water in which HBO undergoes water-assisted tautomerization to give the syn-keto tautomer.

  5. Forest Irrigation Of Tritiated Water: A Proven Tritiated Water Management Tool

    Vangelas, Karen; Blount, Gerald; Kmetz, Thomas; Prater, Phil

    2012-11-08

    Tritium releases from the Old Radioactive Waste Burial Ground (ORWBG) at the SRS in South Carolina has impacted groundwater and surface water. Tritiated groundwater plumes discharge into Fourmile Branch which is a small tributary of the Savannah River, a regional water resource. Taking advantage of the groundwater flow paths and the local topography a water collection and irrigation system was constructed and has been used at the SRS for over a decade to reduce these tritiated water releases to Fourmile Branch. The tritiated water is transferred to the atmosphere by evaporation from the pond surface, and after irrigation, wetted surface evaporation and evapotranspiration through the forest vegetation. Over the last decade SRS has irrigated over 120,000,000 gallons of tritiated water, which diverted over 6000 curies away from Fourmile Branch and the Savannah River. The system has been effective in reducing the flux of tritiated groundwater by approximately 70%. Mass balance studies of tritium in the forest soils before operations and over the last decade indicate that approximately 90% of the tritiated water that is irrigated is transferred to the atmosphere. Dose studies indicate that exposure to site workers and offsite maximally exposed individual is very low, approximately 6 mrem/year and 0.004 mrem/year, respectively. To consistently meet the flux reduction goal of tritium into Fourmile Branch optimization activities are proposed. These efforts will increase irrigation capacity and area. An additional 17 acres are proposed for an expansion of the area to be irrigated and a planting of approximately 40 acres of pine forest plantations is underway to expand irrigation capacity. Co-mingled with the tritiated groundwater are low concentrations of chlorinated volatile organic compounds (cVOCs), and 1,4-dioxane. Research studies and SRS field data indicate the forest irrigation system may have an added benefit of reducing the mass of these co-contaminants via

  6. Acid-base formalism in dispersion-stabilized S-H···Y (Y═O, S) hydrogen-bonding interactions.

    Bhattacherjee, Aditi; Matsuda, Yoshiyuki; Fujii, Asuka; Wategaonkar, Sanjay

    2015-02-19

    The role of sulfhydryl (S-H) group as hydrogen bond donor is not as well studied as that of hydroxyl (O-H). In this work we report on the hydrogen-bonding properties of S-H donor in 1:1 complexes of H2S with diethyl ether (Et2O), dibutyl ether (Bu2O), and 1,4-dioxane (DO). The complexes were prepared in supersonic jet and investigated using infrared predissociation spectroscopy based on VUV photoionization detection. The IR spectra of all the complexes showed the presence of a broad, intensity-enhanced, and red-shifted hydrogen-bonded S-H stretching transition. The S-H stretching frequency was red-shifted by 46, 63, and 49 cm(-1) in H2S-Et2O, H2S-Bu2O, and H2S-DO complexes, respectively, suggesting that all the complexes are S-H···O bound. Computationally, two different S-H···O bound structures, namely, "coplanar" and "perpendicular", were obtained as the minimum energy structures for these complexes at the MP2/6-311++G** level, with the former being the global minimum. However, with Dunning-type basis sets (aug-cc-pVDZ and aug-cc-pVTZ) only the perpendicular structures were found to be stable at the MP2 level. The large widths of the bound S-H stretch observed in the experimental spectra (fwhm of 35 to 80 cm(-1)) were attributed to inhomogeneous broadening due to multiple conformations of the alkyl chains in the coplanar and perpendicular structures populated in the jet. The frequency shifts in the hydrogen-bonded S-H stretching mode as well as the bond dissociation energies of all S-H···Y (Y═O,S) complexes of H2S, which includes the H2S dimer and H2S-methanol (H2S-MeOH) complexes reported in our previous work (ChemPhysChem 2013, 14, 905-914), were found to scale linearly with the proton affinity of the acceptor molecule. In this regard the S-H group, like O-H, is found to conform to the widely accepted acid-base nature of hydrogen-bonding interactions. PMID:25611613

  7. Scientific Opinion on the safety of polyvinyl alcohol-polyethylene glycol-graft-co-polymer as a food additive

    EFSA Panel on Food Additives and Nutrient Sources added to Food (ANS

    2013-08-01

    Full Text Available Following a request from the European Commission, the EFSA Panel on Food Additives and Nutrient Sources added to Food (ANS was asked to deliver a scientific opinion on the safety of polyvinyl alcohol-polyethylene glycol-graft-co-polymer (PVA-PEG graft co-polymer as a film coating for food supplements. PVA-PEG graft co-polymer is a branched molecule consisting of about 75 % PVA and 25 % PEG units. The polymer is currently approved in pharmaceuticals in the EU. The specifications proposed are consistent with those for other already approved film-coating agents for use in the EU, including PVA and PEG, however, the Panel noted that no specifications for the impurities ethylene glycol, diethylene glycol, 1,4-dioxane and ethylene oxide are presently included. The co-polymer is not absorbed from the gastrointestinal tract. In repeated dose oral toxicity studies in animals (rat, rabbit, and dogs no adverse effects were shown. No chronic toxicity/carcinogenicity studies were provided, but no adverse effects following long-term consumption of PVA-PEG graft co-polymer are expected given the absence of any substance-related adverse effects in the shorter-term toxicity studies and the fact that the co-polymer is virtually not absorbed following oral administration. Based on in vitro and in vivo assays the co-polymer is found to be not genotoxic. From a subchronic feeding study in the dog a NOAEL of approximately 800 mg/kg bw/day (highest dose tested was identified. Conservative intake estimates from food supplements amounted to 4.3 mg/kg bw/day for children and 5 mg/kg bw/day for adults leading to a sufficient Margin of Safety compared to the NOAEL. From the maximum residual level of vinyl acetate Margins of Exposure of > 106 were calculated. The Panel concluded that the use of PVA-PEG graft co-polymer food supplements as a film coating is of no safety concern at the proposed uses.

  8. Safety assessment on polyethylene glycols (PEGs) and their derivatives as used in cosmetic products

    , however, considered safe as they are not expected to be systemically available. As all PEGs and PEG derivatives, they must not be applied to damaged skin. Manufacturers of PEGs and PEG derivatives must continue their efforts to remove impurities and by-products such as ethylene oxide and 1,4-dioxane. Overall, it is concluded, that the PEGs covered in this review are safe for use in cosmetics under the present conditions of intended use

  9. Synthesis, properties and applications of bio-based materials

    Srinivasan, Madhusudhan

    silanes on the polyester in short reaction times of 5 minutes. This improved the compatibility with the talc filler. This biodegradable polyester product was characterized by high tensile strength and moderate elongation. The modification method is simple is applicable to a variety of aliphatic biodegradable polyesters. Finally a rapid polymerization of 1, 4-dioxan-2-one in very short times was accomplished with titanium alkoxides as initiators. At low [monomer]/ [initiator] ratios (100:1), nearly all the alkoxide groups initiated polymerization. High conversions up to 90% were achieved even at high ratios (2400:1). The activation energy for polymerization for titanium tetraisopropoxide is the lowest reported (33.5 kJ/mol) for this monomer system.

  10. Final report of the amended safety assessment of PEG-5, -10, -16, -25, -30, and -40 soy sterol.

    2004-01-01

    PEGs Soy Sterol are polyethylene glycol (PEG) derivatives of soybean oil sterols used in a variety of cosmetic formulations as surfactants and emulsifying agents, skin-conditioning agents, and cleansing and solubilizing agents. When the safety of these ingredients were first reviewed, the available data were insufficient to support safety. New data have since been received and the safety of these ingredients in cosmetics has been substantiated. Current concentration of use ranges from a low of 0.05% in makeup preparations to 2% in moisturizers and several other products. PEGs Soy Sterol are produced by the reaction of the soy sterol hydroxyl with ethylene oxide. In general, ethoxylated fatty acids can contain 1,4-dioxane as a byproduct of ethoxylation. The soy sterols include campesterol, stigmasterol, and beta-sitosterol. The distribution of sterols found in oils derived from common plants is similar, with beta-sitosterol comprising a major component. Impurities include sterol hydrocarbons and cholesterol (4% to 6%) and triterpine alcohols, keto-steroids, and other steroid-like substances (4% to 6%). No pesticide residues were detected. PEGS: Because PEGs are an underlying structure in PEGs Soy Sterols, the previous assessment of PEGs was considered. It is generally recognized that the PEG monomer, ethylene glycol, and certain of its monoalkyl ethers are reproductive and developmental toxins. Given the methods of manufacture of PEGs Soy Sterol, there is no likelihood of ethylene glycol or its alkyl ethers being present. Also, the soybean oil sterol ethers in this ingredient are chemically different from the ethylene glycol alkyl ethers of concern. PEGs are not carcinogenic, although sensitization and nephrotoxicity were observed in burn patients treated with a PEG-based cream. No evidence of systemic toxicity or sensitization was found in studies with intact skin. Plant Phytosterols: Intestinal absorption of ingested plant phytosterols is on the order of 5%, with

  11. One barbiturate and two solvated thiobarbiturates containing the triply hydrogen-bonded ADA/DAD synthon, plus one ansolvate and three solvates of their coformer 2,4-diaminopyrimidine.

    Hützler, Wilhelm Maximilian; Egert, Ernst; Bolte, Michael

    2016-09-01

    A path to new synthons for application in crystal engineering is the replacement of a strong hydrogen-bond acceptor, like a C=O group, with a weaker acceptor, like a C=S group, in doubly or triply hydrogen-bonded synthons. For instance, if the C=O group at the 2-position of barbituric acid is changed into a C=S group, 2-thiobarbituric acid is obtained. Each of the compounds comprises two ADA hydrogen-bonding sites (D = donor and A = acceptor). We report the results of cocrystallization experiments of barbituric acid and 2-thiobarbituric acid, respectively, with 2,4-diaminopyrimidine, which contains a complementary DAD hydrogen-bonding site and is therefore capable of forming an ADA/DAD synthon with barbituric acid and 2-thiobarbituric acid. In addition, pure 2,4-diaminopyrimidine was crystallized in order to study its preferred hydrogen-bonding motifs. The experiments yielded one ansolvate of 2,4-diaminopyrimidine (pyrimidine-2,4-diamine, DAPY), C4H6N4, (I), three solvates of DAPY, namely 2,4-diaminopyrimidine-1,4-dioxane (2/1), 2C4H6N4·C4H8O2, (II), 2,4-diaminopyrimidine-N,N-dimethylacetamide (1/1), C4H6N4·C4H9NO, (III), and 2,4-diaminopyrimidine-1-methylpyrrolidin-2-one (1/1), C4H6N4·C5H9NO, (IV), one salt of barbituric acid, viz. 2,4-diaminopyrimidinium barbiturate (barbiturate is 2,4,6-trioxopyrimidin-5-ide), C4H7N4(+)·C4H3N2O3(-), (V), and two solvated salts of 2-thiobarbituric acid, viz. 2,4-diaminopyrimidinium 2-thiobarbiturate-N,N-dimethylformamide (1/2) (2-thiobarbiturate is 4,6-dioxo-2-sulfanylidenepyrimidin-5-ide), C4H7N4(+)·C4H3N2O2S(-)·2C3H7NO, (VI), and 2,4-diaminopyrimidinium 2-thiobarbiturate-N,N-dimethylacetamide (1/2), C4H7N4(+)·C4H3N2O2S(-)·2C4H9NO, (VII). The ADA/DAD synthon was succesfully formed in the salt of barbituric acid, i.e. (V), as well as in the salts of 2-thiobarbituric acid, i.e. (VI) and (VII). In the crystal structures of 2,4-diaminopyrimidine, i.e. (I)-(IV), R2(2)(8) N-H...N hydrogen-bond motifs are preferred and, in two

  12. Influence of inorganic acids on the dehydration of fructose to 5-hydroxymethylfurfural over AlCl3 catalyst%无机酸对 AlCl3催化果糖脱水制备5-羟甲基糠醛的影响

    李振斌; 顾运江; 王维; 魏作君; 刘迎新

    2014-01-01

    The dehydration of fructose to 5-hydroxymethylfurfural is the research hotspot of the compre-hensive utilization of biomass resources. Using AlCl3 as the catalyst,the influence of reaction conditions on the dehydration of fructose to 5-hydroxymethylfurfural,especially the addition of different inorganic acids on the catalytic performance of AlCl3 was investigated. Using inorganic acid and AlCl3 as the co-catalyst, the effects of different solvents(1,4-dioxane,N,N-dimethylformamide,2-dimethyl sulfoxide),reaction temperature and the mass ratio of sulphuric acid to phosphoric acid(1: 2、2: 3、3: 2、2: 1)were tested. The results showed that 5-hydroxymethylfurfural yield of 92. 1% was attained under the condition as follows:N,N-dimethylformamide as the solvent,AlCl3 dosage 7. 5 mmol,sulphuric acid concentration 20 mmol·L -1 , phosphoric acid concentration 30 mmol·L - 1 and reaction temperature 120 ℃.%果糖脱水降解为5-羟甲基糠醛是生物质资源综合利用的研究热点。以 AlCl3为催化剂,考察反应条件对果糖脱水制备5-羟甲基糠醛的影响,重点研究不同无机酸对 AlCl3催化果糖降解生成5-羟甲基糠醛反应的影响。以 AlCl3和无机酸为共催化剂,考察在不同溶剂(1,4-二氧六环、N,N -二甲基甲酰胺、2-甲基亚砜)、反应温度和硫酸与磷酸质量比(1:2、2:3、3:2、2:1)条件下对果糖脱水降解制5-羟甲基糠醛的影响。结果表明,以温和的 N,N -二甲基甲酰胺为溶剂,在反应温度120℃、AlCl3用量为7.5 mmol、硫酸为20 mmol·L -1和磷酸为30 mmol·L -1共催化剂条件下,5-羟甲基糠醛收率达92.1%。

  13. Final report on the safety assessment of Hexamidine and Hexamidine Diisethionate.

    2007-01-01

    clastogenic in mammalian cells. Hexamidine Diisethionate at 0.10% did not provoke primary irritation, inflammation, or sensitization in a clinical test of 200 human subjects. One case report of photosensitivity to Hexamidine and one of contact sensitivity to Hexamidine were reported. There were nine case reports of contact sensitivity to Hexamidine Diisethionate. A European safety assessment recommended a limit of 0.1% Hexamidine Diisethionate in leave-on and rinse-off cosmetic products. In considering the available data, the Cosmetic Ingredient Review (CIR) Expert Panel acknowledged the lack of carcinogenicity and reproductive/developmental toxicity data. Because genotoxicity studies were negative, and there were no structural alerts, the Panel concluded that it was unlikely that these ingredients would be carcinogenic. Because the rate of absorption of Hexamidine and Hexamidine Diisethionate is slow, there is no tissue accumulation, and excretion is rapid and complete, and there was no toxicity in a subchronic study, the Panel concluded that dermal exposures would not likely present a risk of reproductive/developmental toxicity. The Panel noted that a guinea pig maximization study using Hexamidine Diisethionate produced no dermal reactions and that a clinical test at 0.1% produced no irritation or sensitization. The Panel also expressed concern regarding the possible presence of 1,4-dioxane as an impurity, and stressed that the cosmetic industry should continue to use the necessary purification procedures to remove these impurities from the ingredient before blending into cosmetic formulations. The Panel noted that there are no data for concentration of use for eye makeup and baby products, and was concerned that there should not be unrestricted concentration levels in these product categories. Although there are gaps in knowledge about product use, the overall information available on the types of products in which these ingredients are used and at what concentration

  14. Ground-Water Quality Data in the San Fernando-San Gabriel Study Unit, 2005 - Results from the California GAMA Program

    Land, Michael; Belitz, Kenneth

    2008-01-01

    Ground-water quality in the approximately 460 square mile San Fernando-San Gabriel study unit (SFSG) was investigated between May and July 2005 as part of the Priority Basin Assessment Project of the Groundwater Ambient Monitoring and Assessment (GAMA) Program. The GAMA Priority Basin Assessment Project was developed in response to the Groundwater Quality Monitoring Act of 2001 and is being conducted by the U.S. Geological Survey (USGS) in cooperation with the California State Water Resources Control Board (SWRCB). The San Fernando-San Gabriel study was designed to provide a spatially unbiased assessment of raw ground-water quality within SFSG, as well as a statistically consistent basis for comparing water quality throughout California. Samples were collected from 52 wells in Los Angeles County. Thirty-five of the wells were selected using a spatially distributed, randomized grid-based method to provide statistical representation of the study area (grid wells), and seventeen wells were selected to aid in the evaluation of specific water-quality issues or changes in water chemistry along a historic ground-water flow path (understanding wells). The ground-water samples were analyzed for a large number of synthetic organic constituents [volatile organic compounds (VOCs), pesticides and pesticide degradates], constituents of special interest [perchlorate, N-nitrosodimethylamine (NDMA), 1,2,3-trichloropropane (1,2,3-TCP), and 1,4-dioxane], naturally occurring inorganic constituents (nutrients, major and minor ions, and trace elements), radioactive constituents, and microbial indicators. Naturally occurring isotopes (tritium, and carbon-14, and stable isotopes of hydrogen, oxygen, and carbon), and dissolved noble gases also were measured to help identify the source and age of the sampled ground water. Quality-control samples (blanks, replicates, samples for matrix spikes) were collected at approximately one-fifth (11 of 52) of the wells, and the results for these

  15. Final report on the safety assessment of octoxynol-1, octoxynol-3, octoxynol-5, octoxynol-6, octoxynol-7, octoxynol-8, octoxynol-9, octoxynol-10, octoxynol-11, octoxynol-12, octoxynol-13, octoxynol-16, octoxynol-20, octoxynol-25, octoxynol-30, octoxynol-33, octoxynol-40, octoxynol-70, octoxynol-9 carboxylic acid, octoxynol-20 carboxylic acid, potassium octoxynol-12 phosphate, sodium octoxynol-2 ethane sulfonate, sodium octoxynol-2 sulfate, sodium octoxynol-6 sulfate, and sodium octoxynol-9 sulfate.

    Johnson, Wilbur

    2004-01-01

    Octoxynols are ethoxylated alkylphenols in which the size of the molecule is related to the number of moles of ethylene oxide used in synthesis. Reactions are performed at elevated temperature, under pressure, and in the presence of NaOH. It is possible that the synthesis may leave trace amounts of ethylene oxide, 1,4-dioxane, and unreacted C9 phenols. Octoxynols of various chain lengths as well as octoxynol salts and organic acids function in cosmetics either as surfactants--emulsifying agents, surfactants--cleansing agents, surfactant--solubilizing agents, or surfactants--hydrotropes in a wide variety of cosmetic products at concentrations ranging from 0.0008% to 25%, with most less than 5.0%. The octoxynols are chemically similar to nonoxynols, the safety of which were previously considered. Long-chain nonoxynols (9 and above) were considered safe as used, whereas short-chain nonoxynols (8 and below) were considered safe as used in rinse-off products and safe at concentrations less than 5% in leave-on formulations. Acute exposure of hamsters to Octoxynol-9 by bronchopulmonary lavage produced pneumonia, pulmonary edema, and intra-alveolar hemorrhage. Octoxynol-9 at doses over 1 g/kg was toxic in rats and in mice in acute oral toxicity studies. No significant effects were noted in short-term oral studies of Octoxynol-9 in rats, in subchronic oral studies of Octoxynol-40 in rats and dogs, or in chronic oral studies of Octoxynol-40 in rats. The intraperitoneal LD50 of Octoxynol-9 in rats and mice was around 100 mg/kg. In skin irritation studies, octoxynols ranged from nonirritating to moderately irritating. Octoxynols were not ocular irritants in one rabbit study, but in others there was ocular irritation. No immune system toxicity in CF-1 female mice was noted following the intraperitoneal injection of Octoxynol-9 followed by subcutaneous immunization with sheep red blood cells (SRBCs). Octoxynol-9 produced no humoral and cell-mediated immune responses, or

  16. A Development of Rapid, Practical and Selective Process for Preparation of Z-Oximes

    potassium carbonate in refluxing 1,4-dioxane to afford the corresponding ketoxime 2a in excellent yield. Acetophenone oxime (2a) was also obtained by the use of ethanol or methanol as the solvent at room temperature or at reflux temperature in excellent yields (Entries 9-12 in Table 1), whereas the side reaction was detected for the reaction of 1a with hydroxylamine hydrochloride in the presence of potassium carbonate in refluxing water. According to our preliminary results, we selected the methanol as the solvent due to short reaction time and low price. As shown in Table 2, aliphatic and aromatic ketones except for benzophenone (1f) were rapidly and selectively converted to the corresponding Z-oximes in good yields. Also, various types of aromatic aldehydes 1g. with electron donating and withdrawing groups were rapidly and selectively converted to the corresponding Zaldoximes in good to excellent yields. In our condition, the oximation of aldehydes is more Z-selective than the oximation of ketones. In order to evaluate the utility of industrial process, we examined the one mole scale reaction. Treatment of one mole acetophenone (1a) and benzaldehyde (1g) with hydroxylamine hydrochloride and potassium carbonate in methanol afforded the corresponding oximes 2a (E/Z ratio = 15:85, 92%) and 2g (E/Z ratio = 10:90, 92%). The structures of the oximes were established by IR and NMR. In the case of ketoximes, we distinguished two isomers by using the carbon chemical shifts of C=NOH, that is, the chemical shifts of the Z-isomer are detected higher field than the chemical shifts of the E-isomer. In the case of aldoximes, E/Z-isomers were distinguished by using the proton chemical shifts of HC=N for aldoximes, that is, the proton chemical shifts of the Z-isomer are detected lower field than the chemical shifts of the E-isomer. In summury, we have demonstrated the rapid and convenient oximation of ketones and aldehydes with potassium carbonate in methanol at room or reflux temperature