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2006-01-01
Henry's law constants and infinite dilution activity coefficients of cis-2-butene, dimethylether, chloroethane, and 1,1-difluoroethane in methanol, 1-propanol, 2-propanol, 1-butanol, 2-butanol, isobutanol, tert-butanol, 1-pentanol, 2-pentanol, 3-pentanol, 2-methyl-1-butanol, 3-methyl-1-butanol, and 2-methyl-2-butanol in the temperature range of 250 K to 330 K were measured by a gas stripping method and partial molar excess enthalpies were calculated from the activity coefficients. A rigorous formula for evaluating the Henry's law constants from the gas stripping measurements was used for the data reduction of these highly volatile mixtures. The uncertainty is about 2% for the Henry's law constants and 3% for the estimated infinite dilution activity coefficients. In the evaluation of the infinite dilution activity coefficients, the nonideality of the ...
Comparative dielectric study of pentanol isomers with terahertz time-domain spectroscopy
2010-01-01
Using terahertz (THz) time-domain spectroscopy, we have measured the complex permittivity of seven pentanol isomers (1-pentanol, 2-pentanol, 3-pentanol, 2-methly-1-butanol, 3-methyl-1-butanol, 2-methyl-2-butanol, and 3-methyl-2-butanol) in the frequency range of 0.2-2.5THz at temperatures from 253 to 323K. For all samples, the complex permittivity contains the following three components: (i) a high-frequency side of dielectric relaxation processes, (ii) a broad vibration mode around 1.5THz, and (iii) a low-frequency side of an intermolecular stretching mode located above 2.5THz. At low temperatures, the relaxation process moves to a low-frequency range and a peak of the broad vibration mode, which is independent of temperature, is clearly observed around 1.5THz. Spectra in the THz region c...
Densities, refractive indices, speeds of sound, and isentropic compressibilities at 298.15 K for benzene + cyclohexane + 1-pentanol and the binary benzene + 1-pentanol and cyclohexane + 1-pentanol mixtures have been measured as a function of the mole fraction at atmospheric pressure. Densities and speeds of sound were determined by density and sound analyzer Anton Paar DSA-48 and refractive indices by the automatic refractometer ABBEMAT-HP Dr Kernchen.
1996-03-01
Experiments on equilibrium adsorption loadings of various probe compounds on 60-200 mesh Illinois {number_sign}6 coal (PSOC-1539), Adaville {number_sign}1 coal (PSOC-1544), Wyodak coal (PSOC-1545) and Pittsburgh {number_sign}8 coal (PSOC-1549) were performed. the probe compounds include m-cresol, p-cresol, o-cresol, phenol, n-octanol, n-heptanol, n-propanol, isopropanol n-butanol, s-butanol, 2-butanol, t-butanol, 2-naphthol, cyclohexanol, 2-methyl-1-pentanol (2M1P), 4-methyl-2-pentanol (4M2P), benzene and toluene. Equilibrium adsorption of various probe compounds on the coals were measured with the inverse liquid chromatography method. Experiments on flotation of various 60-200 mesh treated coals such as Illinois {number_sign}6 coal (PSOC-1539), Adaville {number_sign}1 coal (PSOC-1544), Wyodak coal (PSOC-1545) and Pittsburgh {number_sign}8 coal (PSOC-1549) were performed. The chosen coals were treated with steam, nitrogen and air at 1 atm and 125-225{degrees}C for 24 hours. The coals were treated with water as well as 20-1000 ppm aqueous alcohol solutions for 3-24 hours at 150-225{degrees}C. The coals also were treated with 20-ppm alcohol aqueous solutions for 1-24 hours at the 0.002-g/min mass flow rate of alcohol aqueous solutions and at 225{degrees}C. Flotation experiments were conducted with a 500-cm{sup 3} batch-type micro flotation apparatus, introducing nitrogen at the bottom of the apparatus. This final report was prepared with the experimental data obtained during the period of September 1991-March 1994.
2006-01-01
The excess molar volumes (VmE) and viscosities () for binary mixtures of dipropylene glycol tert-butyl ether with methanol, 1-propanol, 1-pentanol, and 1-heptanol and viscosities of dipropylene glycol monomethyl ether and dipropylene glycol monobutyl ether with methanol, 1-pentanol, and 1-heptanol have been reported at 298.15 K. The VmE are negative for the mixtures investigated. Sign and magnitude of VmE and viscosity deviations were used to analyze the mixing behavior of the components.
1994-01-01
Excess molar volumes of mixtures of heptane + 1-propanol, 1-pentanol, or 1-heptanol were determined from density measurements at 278.15, 288.15, 298.15, and 308.15 K. From these results ([delta]V[sup E]/[delta]T)[sub P] and ([delta]H[sup E]/[delta]P)[sub T] at 298.15 K were calculated. The results were compared with the values calculated using the Nitta-Chao theory of liquid mixtures.
2008-01-01
A high pressure flow-mixing isothermal microcalorimeter was used to determine molar excess enthalpies of six binary systems for 2,4-pentanedione + (1-butanol, + 2-methyl-1-propanol, + 1-pentanol, + 1-heptane, + ethyl acetate, and + water) at T=298.15, 313.15, and 328.15K and p=0.1 and 10.0MPa. The molar excess enthalpies increased with an increase of the temperature and the molecular size of alcohols and decreased slightly with an increase of pressure. The experimental data were correlated by the Redlich-Kister equation and three local composition models (Wilson, NRTL, and UNIQUAC).
2008-02-15
Measurements of compressed liquid densities for 1-pentanol and for {l_brace}CO{sub 2} (1) + 1-pentanol (2){r_brace} system were carried out at temperatures from 313 K to 363 K and pressures up to 25 MPa. Densities were measured for binary mixtures at 10 different compositions, x{sub 1} = 0.0816, 0.1347, 0.3624, 0.4651, 0.6054, 0.7274, 0.8067, 0.8573, 0.9216, and 0.9757. A vibrating tube densimeter was used to perform density measurements using two reference calibration fluids. The uncertainty is estimated to be better than {+-}0.2 kg . m{sup -3} for the experimental density measurements. For each mixture and for 1-pentanol, the experimental densities were correlated using an explicit volume equation of six parameters and an 11-parameter equation of state (EoS). Excess molar volumes were determined for the (CO{sub 2} + 1-pentanol) system using 1-pentanol densities calculated from the 11-parameter EoS and CO{sub 2} densities calculated from a multiparameter reference EoS.
Thermodynamic study of the n-octane-1-pentanol-sodium dodecyl sulfate solutions in water
2007-01-01
The thermodynamic properties, PVTx (T S, P S, rho S) (partial derivP/partial derivT) VX, and C V VTx, of three microemulsions (water + n-octane + sodium dodecylsulfate + 1-pentanol) with composition of solution-1: 0.0777 (H2O):0.6997 (n-C8H18):0.0777 (SDS):0.1449 (1-C5H11OH) mass fraction. Solution-2: 0.6220 (H2O):0.1555 (n-C8H18):0.0777 (SDS):0.1448 (1-C5H11OH) mass fraction. And solution-3: 0.2720 (H2O):0.5054 (n-C8H18):0.0777 (SDS):0.1449 (1-C5H11OH) mass fraction were measured. Sodium dodecylsulfate (SDS) was used as an ionic surfactant, 1-pentanol used as ...
1990-08-15
Surface Raman scattering is used to study the adsorption of several straight-chain alcohols (methanol, 1-propanol, 1-pentanol) and a straight-chain alkanethiol (1-butanethiol) at Ag electrodes. Surface-enhanced Raman scattering (SERS) studies are carried out on both in situ and emersed roughened electrodes. Normal surface Raman scattering is performed on mechanically polished, mirrored polycrystalline electrodes that have been emersed from solution. It is generally observed that the Raman scattering results, in terms of the orientation and bonding for the alcohols and the thiol, are similar on rough and mirrored electrodes. This observation suggests that SERS probes the average surface molecules in these cases and not only those existing at chemically distinct surface sites. The utility of emersed electrode approaches for molecular characterization of the electrochemical interface is demonstrated for these systems. The interfacial molecular structure for these in situ organic species appears to be maintained upon emersion.
Solubilization and biodegradation of polycyclic aromatic hydrocarbons in microemulsions
2009-07-01
This study investigated the feasibility of using microemulsions to enhance the biodegradation of polycyclic aromatic hydrocarbons (PAHs). Microemulsions are commonly used in soil washing as a means of enhancing the solubility of hydrophobic pollutants. The microemulsions were composed of Tween-80, 1-pentanol and linseed oil. Phenanthrene (PHE) was dissolved in dichloromethane and added to a glass vial. Microemulsions were added separately to the vials. A high performance liquid chromatograph (HPLC) was used to determine PHE concentrations. The vials were inoculated with an isolated PAH degradative bacterium Bacillus subtilis B-UM. Soil collected from abandoned shipyards in Hong Kong were then spiked with the mixtures and aged for 3 months. One way analysis of variance (ANOVA) analyses were conducted. Results of the study showed that a microemulsion composed of 0.4 Tween-80, 0.1 per cent 1-pentanol, and 0.05 linseed oil effectively enhanced the biodegradation of PHE in the aqueous phase. It was concluded that microemulsions can be used to remediate soils contaminated by PAHs. 26 refs., 2 tabs., 4 figs.
2006-01-15
Density and viscosity measurements for binary mixtures of (1,1,2,2-tetrabromoethane + 1-pentanol, or + 1-hexanol, or + 1-heptanol, or + 1-octanol, or + 1-decanol) at T = (293.15 and 303.15) K, have been conducted at atmospheric pressure. The excess molar volumes V {sup E}, have been calculated from the experimental measurements, and the results were fitted to Redlich-Kister equation. The viscosity data were correlated with the model of Grunberg and Nissan, and McAllister four-body model. The excess molar volumes of (1,1,2,2-tetrabromoethane + 1-pentanol, or + 1-haxanol, or + 1-heptanol, or + 1-octanol) had a sigmoidal shape and the values varied from negative to positive with the increase in the molar fraction of 1,1,2,2-tetrabromoethane. The remaining binary mixture of (1,1,2,2-tetrabromoethane + 1-decanol) was positive over the entire composition range. The effects of the 1-alkanol chain length as well as the temperature on the excess molar volume have been studied. The results have been qualitatively used to explain the molecular interaction between the components of these mixtures.
2010-01-01
A flow-mixing isothermal microcalorimeter has been used to determine the excess molar enthalpies for five binary systems of diethyl malonate+ (1-butanol, 2-methyl-1-propanol, 1-pentanol, n-heptane, and ethyl acetate) at T= (288.2, 298.2, 313.2, 328.2, 338.2, and 348.2K) and p=101.3kPa. The Hm^E values increase with increasing temperature. The experimental data have been correlated by the Redlich-Kister equation and two local composition models (NRTL and UNIQUAC).
Neurotoxic metabolites of ''commercial hexane'' in the urine of shoe factory workers
1981-12-01
Urinary metabolites were tested in 41 shoe-factory workers exposed to a mixture of 10 solvents among which ''commercial hexane'' was the prevailing component. Cyclohexanol, 2-methyl-2-pentanol, 3-methyl-2-pentanol, and trichloroethanol were determined in connection with exposure to cyclohexane, 2-methylpentane, 3-methylpentane, and trichloroethylene, respectively. 2-Hexanol, 2,5-hexanedione, 2,5-dimethylfuran, and gamma-valerolactone were all determined in connection with n-hexane exposure only. 2,5-Hexanedione was the principal n-hexane metabolite found in the workers' urine. This finding of the experimentally proven neurotoxin 2,5-hexanedione in the urine of shoe-factory workers exposed to ''commercial hexane'' is consistent with the idea that this compound is responsible for the development of neuropathy in this group of individuals.
2007-01-01
The molecular interaction between alkyl methacrylates (methyl methacrylate, ethyl methacrylate and butyl methacrylate) and primary alcohols (1-propanol, 1-butanol, 1-pentanol, 1-heptanol, 1-octanol and 1-decanol) has been studied in carbon tetrachloride by FTIR spectroscopic and dielectric methods. The results show that the most likely association between alcohol and ester is 1:1 complex through the free hydroxyl group of the alcohol and the carbonyl group of ester, and the alkyl chain length of both the alcohols and esters plays an important role in the determination of the strength of hydrogen bond (O-H:O=C) formed
2007-01-01
The molecular interaction between alkyl methacrylates (methyl methacrylate, ethyl methacrylate and butyl methacrylate) and primary alcohols (1-propanol, 1-butanol, 1-pentanol, 1-heptanol, 1-octanol and 1-decanol) has been studied in carbon tetrachloride by FTIR spectroscopic and dielectric methods. The results show that the most likely association between alcohol and ester is 1:1 complex through the free hydroxyl group of the alcohol and the carbonyl group of ester, and the alkyl chain length of both the alcohols and esters plays an important role in the determination of the strength of hydrogen bond (O-H:OC) formed.
Cholesterol autoxidation: identification of the volatile fragments.
The volatile fragments of air-aged cholesterol were analysed by means of gas chromatography-mass spectrometry; The following fourteen compounds were identified: ethanol, acetic acid, acetone, 2-methylpropene, 2-methyl-1-propanol, 2-methyl-2-propanol, 2-butanone, 2-methylpropionic acid, 2-methyl-2-butanol, 2-pentanone, 3-methyl-2-butanone, 2-methyl-1-pentene, 2-methyl-2-pentanol, and 2-methyl-4-penten-2-ol. Their formation via decomposition of initially formed sterol hydroperoxides is discussed.
1982-03-01
Excess volumes for binary mixtures of 1-chlorobutane with 1-propanol, 1-butanol, 1-pentanol, 1 hexanol, 1-heptanol and 1-octanol have been determined at 303.15 K. V/sup E/ is positive over the whole range of composition for the mixtures of 1-chlorobutane with 1-propanol and 1-butanol. An inversion in the sign of V/sup E/ is observed over certain ranges of concentration of the halogenated alkane in the remaining four mixtures. The results are explained in terms of depolymerisation of hydrogen-bonded alcohol aggregates, decrease in dipolar association, and weak hydrogen-bonding interaction of the type Cl---H/EN DASH/O between unlike molecules. 7 refs.
2007-01-01
Densities (rho), speeds of sound (u), isentropic compressibilities (ks), refractive indices (nD), and surface tensions (sigma) of binary mixtures of methyl salicylate (MSL) with 1-pentanol (PEN) have been measured over the entire composition range at the temperatures of 278.15K, 288.15K, and 303.15K. The excess molar volumes (VE), excess surface tensions (sigmaE), deviations in speed of sound (DELTAu), deviations in isentropic compressibility (DELTAks), and deviations in molar refraction (DELTAR) have been calculated. The excess thermodynamic properties VE, sigmaE, DELTAu, DELTAks, and DELTAR were fitted to the Redlich-Kister ...
Temperature dependence of the volumetric properties of some alkoxypropanols + n-alkanol mixtures
2004-01-01
The excess molar volumes VmE for binary liquid mixtures containing dipropylene glycol monomethyl ether or dipropylene glycol monobutyl ether and methanol, 1-propanol, 1-pentanol and 1-heptanol have been measured as a function of composition using a continuous dilution dilatometer at T=(288.15, 298.15, and 308.15) K and atmospheric pressure over the whole concentration range. The excess volume results allowed the following mixing quantities to be reported in all range of concentrations or at equimolar concentrations: alpha, volume expansivity. (partial derivVmE/partial derivT)p. (partial derivHE/partial derivP)T at T=298.15 K. The obtained results have been compared at T=298.15 K with the calculated values ...
1991-01-01
A method is described for the synthesis, purification and radiolabelling of [123I/131I]2-left brace5-(4-iodophenyl)-pentylright braceoxirane-2-carboxylic acid ethyl ester. For the synthesis of this new agent, 5-phenylpentyl bromide, synthesized by reacting 5-phenyl-1-pentanol with sodium bromide under acidic conditions, was converted to diethyl 5-phenylpentylmalonate, which, on alkaline hydrolysis, yielded ethyl 5-phenyl-pentylmalonate. Ethyl 7-phenyl-2-methyleneheptanoate, prepared from the monoester, was oxidized with m-chloroperbenzoic acid to yield ethyl 2-(5-phenylpentyl)oxirane-2-carboxylate 5. The method of radiolabelling, based on the thallation of compound and the subsequent treatment with radioiodide, resulted in a regioselective radioiodination with a 54% radiochemical ...
Synthesis of ZnO nanostructures in organic solvents and their photoluminescence properties
2010-01-01
Various zinc oxide (ZnO) nanostructures were prepared in different polar organic solution of NaOH via a facile self-assembly solvothermal growth process. ZnO nanoparticles, nanowires, nanorods and nanoneedles with different sizes were fabricated depending on the properties of polar organic solvents. The effects of polar organic solvents including methanol, ethanol, 1-propanol, 1-butanol, 1-pentanol, 1-hexanol, acetone and isopropanol on the forms and morphologies of ZnO nanostructures were investigated, and the corresponding reaction mechanism was preliminarily proposed. The corresponding photoluminescence (PL) spectra exhibited different optical properties of the ZnO nanostructures. We deduce that surface defects of the nanostructures are the main reason for the PL properties observed in ...
The substrate utilization rates of human cutaneous alcohol dehydrogenase were determined for 7 lower aliphatic primary alcohols: ethanol, propanol, butanol, pentanol, 2-methylpropanol, 3-methylbutanol, and 2,2-dimethyl-propanol. 1-Pentanol gave the highest relative activity and 2,2-dimethylpropanol the lowest. The frequency of erythemogenesis was determined in vivo for these 7 lower aliphatic primary alcohols. The frequency of erythemogenesis correlated strongly and significantly with the rate of substrate utilization by alcohol dehydrogenase. These results are consistent with the view that the reaction to primary alcohols applied topically to human skin is provoked, in large part, by the corresponding aldehyde.
2010-01-01
Measurements of ultrasonic speeds, isentropic compressibilities and viscosities were carried out for six ternary mixtures namely dimethylsulphoxide (1) + 1,2-dichlorobenzene (2) + 1-alkanols (3) at 303.15 K. The 1-alkanols include 1-propanol, 1-butanol, 1-pentanol, 1-hexanol, 1-heptanol and 1-octanol. The ultrasonic speeds of these ternary mixtures were also evaluated on the basis of Jacobson's free length theory and Schaaff's collision factor theory. From the viscosity data, deviations in viscosity and interaction parameters for various models were also calculated. An attempt has also been made to explain the nature of intermolecular interactions in the light of deviation in isentropic compressibilities and interaction parameter.
Molecular interaction of alcohols with acrylic esters in non-polar solvents
2006-01-01
The molecular interaction between alcohols (1-propanol, 1-pentanol, 1-heptanol, and 1-octanol) and acrylic esters (methyl methacrylate (MMA), ethyl methacrylate (EMA) and butyl methacrylate (BMA)) have been studied in carbon tetrachloride and benzene at 298 K using dielectric and FTIR spectroscopic methods. The result shows that, 1:1 complex is predominant in these systems. The strength of hydrogen bond (O–H:C=O) formation shows a significant dependence of on alkyl chain length of both alcohols and acrylic esters and the nature of the solvent used. To cite this article: K. Dharmalingam, et al., C. R. Chimie 9 (2006).
Molar excess enthalpies at T=298.15K for (1-alkanol+dibutylether) systems
2010-01-01
Molar excess enthalpies, Formula Not Shown , at T=298.15K and atmospheric pressure have been measured using a microcalorimeter Tian-Calvet for the (methanol, 1-propanol, 1-butanol, 1-pentanol, 1-hexanol, 1-octanol, or 1-decanol+dibutylether) systems. Experimental results have been compared with those obtained from the ERAS, DISQUAC, and Dortmund UNIFAC models. DISQUAC and ERAS yield similar Formula Not Shown , results. Larger differences between experimental and calculated Formula Not Shown , values are obtained from UNIFAC. ERAS represents quite accurately the excess molar volumes, Formula Not Shown , of these systems. The excess molar internal energy at constant volume, Formula Not Shown , is nearly constant for the solutions with the longer 1-alkanols. This points out that the different...
Molar excess enthalpies at T = 298.15 K for (1-alkanol + dibutylether) systems
2010-01-01
Molar excess enthalpies, HmE, at T = 298.15 K and atmospheric pressure have been measured using a microcalorimeter Tian-Calvet for the (methanol, 1-propanol, 1-butanol, 1-pentanol, 1-hexanol, 1-octanol, or 1-decanol + dibutylether) systems. Experimental results have been compared with those obtained from the ERAS, DISQUAC, and Dortmund UNIFAC models. DISQUAC and ERAS yield similar HmE, results. Larger differences between experimental and calculated HmE, values are obtained from UNIFAC. ERAS represents quite accurately the excess molar volumes, VmE, of these systems. The excess molar internal energy at constant volume, UV,mE, is nearly constant for the solutions with the longer 1-alkanols. This points out that the different ...
2010-01-01
An apparatus based on a static-analytic method assembled in this work was utilized to perform high pressure (vapour + liquid) equilibria measurements with uncertainties estimated at 2 + 1-propanol), (CO2 + 2-methyl-1-propanol), (CO2 + 3-methyl-1-butanol), and (CO2 + 1-pentanol) binary systems at temperatures of (313, 323, and 333) K, and at pressure range of (2 to 12) MPa. For all the (CO2 + alcohol) systems, it was visually monitored to insure that there was no liquid immiscibility at the temperatures and pressures studied. The experimental results were correlated with the Peng-Robinson equation of state using the quadratic mixing rules of van der Waals with two adjustable parameters. The calculated (vapour + liquid) ...
2008-04-15
The solubilities of trans-resveratrol in methanol, ethanol, 1-propanol, 2- propanol, 1-butanol, 1-pentanol, 1-hexanol, ethyl acetate, tetrahydrofuran, acetone, and water (pH 6.0) solvents were measured at T = (278.2, 288.2, 298.2, 308.2, and 318.2) K. The solubilities of trans-resveratrol in selected solvents increase with temperature, but decrease with increasing the number of carbon in alcohol solvents. The experimental data were correlated using a thermodynamic equation.
Liquid-liquid equilibrium of (water+1-propanol+1-pentanol) system at 298.15 and 323.15K
2010-01-01
Liquid-liquid equilibrium data for the ternary system water+1-propanol+1-pentanol have been determined experimentally at 298.15 and 323.15K using ''static-analytic'' apparatus involving ROLSI(TM) samplers. The experimental data are correlated considering both NRTL and UNIQUAC activity coefficient models. The results obtained show the ability of both models for the determination of liquid-liquid equilibrium data of the studied system. The reliability of the experimental tie-line data is determined through the Othmer-Tobias and Bachman equations.
1993-11-01
Experiments were performed on equilibrium adsorption of probes (2-methyl-1-pentanol (2M1P), 1-heptanol, benzene, toluene) on 60-200 mesh Illinois 6 coal, Adaville 1 coal, Wyodak coal, and Pittsburgh 8 coal. Equil. loadings of toluene are higher than those of benzene on the 4 coals. The aromatics (tolene, benzene) obey the Langmuir isotherm model for single-layer adsorption up to 100 ppM. Loadings of 2M1P and 1-heptanol do not follow both the Langmuir and the Freundlich empirical model. Flotation of the coals, equilibrated with aq. solns. of 2M1P and 1-heptanol, increase linearly with Equil. loadings. Equil. adsorption loadings of 1-heptanol on Illinois 6 coal increase with decreased adsorption temperature.
High-pressure vapor-liquid equilibria for mixtures containing a supercritical fluid
1994-08-01
Supercritical fluid extraction has been proven as an efficient separation method for some specific industrial applications. The knowledge of the phase behavior of supercritical systems plays an important role in the process design. High pressure vapor-liquid phase equilibrium compositions were measured for the binary systems of carbon dioxide + 2-methyl-1-pentanol, carbon dioxide + 1-octanol, and carbon dioxide + 1-decanol over a temperature range between 348.15 and 453.15 K. In addition to the new data, a variety of supercritical fluid systems was used to test the validity of the Peng-Robinson and Patel-Teja equations of state accompanied by several types of mixing rules. In general, the Peng-Robinson equation incorporated with the cubic mixing rule yielded the best representation.
Excess volumes of binary mixtures of benzene + 1-alkanols at 298. 15 and 308. 15 K
1994-07-01
Excess molar volumes V[sup E] of the binary mixtures of benzene + 1-butanol, + 1-pentanol, + 1-hexanol, + 1-heptanol, + 1-octanol, + 1-nonanol, or + 1-decanol are presented at 298.15 and 308.15 K. The values of V[sup E] are positive over the entire range of composition for these mixtures. All the measurements were made at constant temperature, employing a thermostat that could be maintained to [+-]0.01 K. The error in V[sup E] is estimated to be less than 0.02 cm[sup 3]/mol.
Effect of temperature on the stress corrosion cracking of zircaloy-4 in iodine alcoholic solutions
2007-01-01
Zircaloy-4 is susceptible to stress corrosion cracking (SCC) in solutions of iodine dissolved in different alcohols (methanol, ethanol, 1-propanol, 1-butanol, 1-pentanol and 1-octanol). The crack propagation rate is known to decrease as the solvent molecular weight increases, as a consequence of steric hindrance. However, the mechanism that operates during SCC is still unknown. In the present work the effect of temperature on SCC susceptibility was evaluated in 1-butanol and 1-pentanol iodine containing solutions. The dependence of the crack growth rate with temperature follows an Arrhenius law, and the activation energy obtained from experimental data is consistent with a process controlled by volume diffusion of the active species (the iodine-alcohol complex) to the crack tip.
2010-01-01
The surface tensions of pure ionic liquid, 1-butyl-3-methylimidazolium thiocyanate ([BMIM][SCN]), and binary mixtures of [BMIM][SCN] with alcohols (1-butanol, 1-pentanol, 1-hexanol) have been measured at atmospheric pressure at five temperatures in the range from 298.15 to 328.15K. These measurements have been provided to complete information of the influence of temperature on surface tension for the selected ionic liquid, which was chosen as a possible new entrainer in extraction processes. The surface thermodynamic functions such as surface entropy and enthalpy have been derived from the temperature dependence of the surface tension values, as well as the critical temperature, parachor, and speed of sound for pure ionic liquid. The investigations include the effect of the alkyl chain len...
Bacterial fermentations generally produce 1-butanol together wth acetone, ethanol, 2-propanol, or 1-pentanol. The effect of these materials on the extraction of 1-butanol from aqueous solution by the ethyl ester of soybean oil fatty acids was determined using a factorial experimental design. Concentrations of 1-butanol ranged from 0.1 to 4.1% w/v, while the concentrations of coproduced alcohols and ketones ranged up to 4.0% w/v. Acetone, ethanol, and 2-propanol had little effect on 1-butanol extraction, while a slight increase in extraction appeared with increasing 1-pentanol. The extraction of acetone, ethanol, 2-propanol, and 1-pentanol was not measured. 9 refs., 4 tabs.
1985-01-01
Bacterial fermentations generally produce 1-butanol together wth acetone, ethanol, 2-propanol, or 1-pentanol. The effect of these materials on the extraction of 1-butanol from aqueous solution by the ethyl ester of soybean oil fatty acids was determined using a factorial experimental design. Concentrations of 1-butanol ranged from 0.1 to 4.1% w/v, while the concentrations of coproduced alcohols and ketones ranged up to 4.0% w/v. Acetone, ethanol, and 2-propanol had little effect on 1-butanol extraction, while a slight increase in extraction appeared with increasing 1-pentanol. The extraction of acetone, ethanol, 2-propanol, and 1-pentanol was not measured. 9 refs., 4 tabs.
1993-06-01
Dielectric constant ([epsilon]) of Tri-n-butyl phosphate (TBP), in binary mixtures with five long-chain primary alcohols viz; 1-butanol, 1-pentanol, 1-hexanol, 1-heptanol and 1-octanol has been measured at [nu] = 455 kHz and at temperature 302 K. The data is used to evaluate mutual correlation factor g[sub ab], excess molar polarization [Delta]P and excess free energy of mixing [Delta]F[sub ab] by using Winkelmann-Quitzsch eqn. for binary mixtures to assess the suitability of the alcohols as modifiers. The trend of variation of these parameters exhibit marked dependence on chain-length of the alcohols indicating 1-heptanol to be an efficient modifier. (author).
Determination of C/sub 1/-C/sub 4/ alcohols in gasoline using multiple ion detection
A method for the determination of C/sub 1/-C/sub 4/ alcohol content in gasoline by capillary column gas chromatography-ion trap detector system (GC-ITDS) is described. The method involves the direct injection of gasoline into the GC-ITDS, and subsequent detection of the alcohols using the multiple ion detection method. The detection method uses the mass-to-charge ratio peaks at 31 and 45 for the quantification of the alcohols. 1-Pentanol is used as an internal standard. The method was evaluated over the range of 0-20% for methanol and ethanol and 0-1% for 2-propanol, 1-propanol, 2-methyl-2-propanol, 1-methylpropanol, 2-methylpropanol, and 1-butanol. Detection limits for each of the alcohols are less than 0.1%.
Determination of C/sub 1/-C/sub 4/ alcohols in gasoline using multiple ion detection
1986-10-01
A method for the determination of C/sub 1/-C/sub 4/ alcohol content in gasoline by capillary column gas chromatography-ion trap detector system (GC-ITDS) is described. The method involves the direct injection of gasoline into the GC-ITDS, and subsequent detection of the alcohols using the multiple ion detection method. The detection method uses the mass-to-charge ratio peaks at 31 and 45 for the quantification of the alcohols. 1-Pentanol is used as an internal standard. The method was evaluated over the range of 0-20% for methanol and ethanol and 0-1% for 2-propanol, 1-propanol, 2-methyl-2-propanol, 1-methylpropanol, 2-methylpropanol, and 1-butanol. Detection limits for each of the alcohols are less than 0.1%.
2006-04-15
Densities, excess molar volumes, refractive indices, and changes in refractive index on mixing for 1,1,2,2-tetrachloroethane + 1-pentanol, or 1-hexanol, or 1-heptanol, or 1-octanol, or 1-decanol have been determined at T = (293.15 and 303.15) K. The excess molar volumes and changes in refractive index have been fitted to Redlich-Kister polynomials. The effect of the chain length of the 1-alkanol on the excess molar volume and the change in the refractive index of its mixtures with 1,1,2,2-tetrachloroethane was discussed. In addition, the refractive indices were compared with calculated values using mixing rules proposed by several authors, and a very good agreement was obtained.
2006-09-15
Densities, excess molar volumes, refractive indices, and changes in refractive index on mixing for (1,1,2,2-tetrabromoethane + 1-pentanol, or 1-hexanol, or 1-heptanol, or 1-octanol, or 1-decanol) have been determined at T = 293.15 K and at T = 303.15 K. The excess molar volumes and changes in refractive index have been fitted to Redlich-Kister polynomials. The effect of the chain length of the 1-alkanol on the excess molar volume and the change in the refractive index of its mixtures with 1,1,2,2-tetrabromoethane are discussed. In addition, the refractive indices are compared with calculated values using mixing rules proposed by several authors, and a good agreement is obtained.
Cloud point measurements of 1-butyl-2,3-dimethylimidazolium tetrafluoroborate with alcohols
2010-01-01
Mutual solubility data of imidazolium-based ionic liquid, 1-butyl-2,3-dimethylimidazolium tetrafluoroborate ([bmmim][BF4]) with the alcohols, 1-propanol, 2-propanol, 1-butanol, 1-pentanol, and 1-hexanol were obtained by a cloud point method. The upper critical solution temperatures of the ionic liquid and alcohol mixtures were determined from the mutual solubility data. The upper critical solution temperature of the binary mixtures gradually increased as the chain length of the alcohol increased. The mutual solubility data of binary systems ([bmmim][BF4]+alcohols) have been correlated by the original UNIQUAC model as well as the extended and modified form of the UNIQUAC model. The temperature dependence of the mutual solubility data could be represented in terms of the temperature dependen...
Experiments on equilibrium adsorption of various alcohols on 60--200 mesh Illinois No. 6 coal (DECS-2; Randolph county) were performed during the July--September period. The alcohols include ethanol, methanol, isobutanol, t-butanol, 1-heptanol, 1-octanol, 1-hexadecanol, 4-methyl-2-pentanol, and 2-methyl-l-pentanol. Amounts of equilibrium adsorption of alcohols (ALCO) on 60--200 mesh Illinois No. 6 coal are 1 - 230 {times} 10{sup {minus}6} mg-ALCO/g-coal, whereas equilibrium concentrations of alcohols are 3--40 ppM. Relations between equilibrium loadings of alcohols on the coal and equilibrium concentrations of alcohols in aqueous solutions are shown to be linear.
1992-12-15
Experiments on equilibrium adsorption of various alcohols on 60--200 mesh Illinois No. 6 coal (DECS-2; Randolph county) were performed during the July--September period. The alcohols include ethanol, methanol, isobutanol, t-butanol, 1-heptanol, 1-octanol, 1-hexadecanol, 4-methyl-2-pentanol, and 2-methyl-l-pentanol. Amounts of equilibrium adsorption of alcohols (ALCO) on 60--200 mesh Illinois No. 6 coal are 1 - 230 {times} 10{sup {minus}6} mg-ALCO/g-coal, whereas equilibrium concentrations of alcohols are 3--40 ppM. Relations between equilibrium loadings of alcohols on the coal and equilibrium concentrations of alcohols in aqueous solutions are shown to be linear.
Liquid chromatographic analysis of coal surface properties
1992-12-15
Experiments on equilibrium adsorption of various alcohols on 60--200 mesh Illinois No. 6 coal (DECS-2; Randolph county) were performed during the July--September period. The alcohols include ethanol, methanol, isobutanol, t-butanol, 1-heptanol, 1-octanol, 1-hexadecanol, 4-methyl-2-pentanol, and 2-methyl-l-pentanol. Amounts of equilibrium adsorption of alcohols (ALCO) on 60--200 mesh Illinois No. 6 coal are 1 - 230 [times] 10[sup [minus]6] mg-ALCO/g-coal, whereas equilibrium concentrations of alcohols are 3--40 ppM. Relations between equilibrium loadings of alcohols on the coal and equilibrium concentrations of alcohols in aqueous solutions are shown to be linear.
1987-04-09
Electron spin echo modulation (ESEM) and electron spin resonance (ESR) spectra of the photogenerated N,N,N',N'-tetramethylbenzidine cation radical (TMB/sup +/) in frozen micellar solutions of sodium dodecyl sulfate containing 2-propanol, 1-propanol, 1-pentanol, 1-octanol, 2-propanol-d/sub 7/, and 1-octanol-d/sub 17/ in H/sub 2/O and D/sub 2/O have been studied as a function of the alcohol concentration from 0 to 200 mM. Modulation effects due to the TMB/sup +/ interactions with deuteriums in D/sub 2/O and in 2-propanol-d/sub 7/ or 1-octanol-d/sub 17/ give direct evidence that 2-propanol is mainly located at the micellar interface whereas the alkyl chain of 1-octanol is located deeper into the micelle. Alcohol addition leads to an increase of water penetration into the micellar interface in the order 1-propanol < 2-propanol approx.= 1-pentanol < 1-octanol. The initial efficiency of charge separation upon potoionization of TMB as a function of alcohol concentration correlates with the degree of water penetration into the micelle, but the maximum photoionization efficiency seems more related to the degree of water organization at the micellar surface due to specific perturbing effects on the micellar structure dependent on the alcohol structure.
The solubility of hydrophobic aromatic chemicals in organic solvent/water mixtures
1989-01-01
The influence of dissolved organic solvents on the aqueous phase solubility of hydrophobic aromatic chemicals was investigated. To provide a basis for a comprehensive evaluation of the importance of cosolvent properties on solubility, the effects of several different organic cosolvents on the solubility of a model hydrophobic solute, naphthalene, were determined. Naphthalene solubility was measured in binary, ternary, and quaternary alcohol/water (methanol, ethanol, 1-propanol, 1-butanol, 1-pentanol) mixtures, binary ketone/water (acetone, methylethylketone, diethylketone), and aromatic organic solvent/water (benzene, toluene) mixtures. The solubility data were statistically evaluated and used to obtain an estimate of the overall accuracy of solubility measurements of hydrophobic chemicals in organic solvent/water mixtures. An accurate data base for mixed solvent solubility was established by combining the solubility data with additional solubility data obtained experimentally and from the literature. Thermodynamic models for predicting solubility in organic solvent/water mixtures were tested against the experimental data. The effects of organic cosolvent properties and solute hydrophobicity on solubility behavior and model predictive capability were evaluated. The results were used to evaluate the accuracy of existing models for predicting solubility and to explore possible molecular interactions in organic solvent/water mixtures.
2010-01-01
Non-viral gene delivery vectors were developed for efficient gene transfer to hard-to-transfect mouse mammary epithelial cells. Ten modified versions of the same base poly(beta-amino ester), poly(1,4-butanediol diacrylate-co-5-amino-1-pentanol), were tested in both traditional 2-D monolayer and in 3-D organotypic cultures. The polymers self-assembled with plasmid DNA encoding enhanced green fluorescent protein to form nanoparticles (100 nm) used to transfect the cells. Nanoparticle transfection efficacy was tuned by changes in synthesis and fabrication conditions and the transfection efficacy was analyzed using confocal microscopy and flow cytometry. The best performing polymeric nanoparticles transfected 57 +- 6% of the cells in 2-D culture and 6 +- 1% of the cells in 3-D culture. Small m...
1994-04-01
The effect of medium chain length alcohols on the micellar size and shape of sodium dodecyl sulfate in electrolyte solutions has been investigated by means of small angle neutron scattering (SANS), dynamic light scattering (DLS), and viscosity measurements. The surfactant content was kept constant throughout, at 0.04 m, and the alcohols used were 1-butanol, 1-pentanol, and 1-hexanol. The data from the various techniques are qualitatively in agreement. The SANS data generally fit a model for prolate ellipsoids with varying ratios of the major to minor axis. Addition of butanol first leads to a decrease in micellar size, the major to minor axis ratio decreases from about 6 to less than 2. However, as the butanol concentration exceeds 0.5 m, the micelles starts to grow again. The same can be seen from the diffusion coefficient as measured by DLS. Addition of pentanol or hexanol do not bring about this minimum in micellar size. The minor axis decreases and the major axis increases as these alcohols are added. Thus these alcohols make the prolate ellipsoidal micelles grow continuously towards large rod-like structures. The viscosity data are less detailed, but confirm the general trend upon alcohol addition.
1991-01-01
A method is described for the synthesis, purification and radiolabelling of ({sup 123}I/{sup 131}I)2-{l brace}5-(4-iodophenyl)-pentyl{r brace}oxirane-2-carboxylic acid ethyl ester. For the synthesis of this new agent, 5-phenylpentyl bromide, synthesized by reacting 5-phenyl-1-pentanol with sodium bromide under acidic conditions, was converted to diethyl 5-phenylpentylmalonate, which, on alkaline hydrolysis, yielded ethyl 5-phenyl-pentylmalonate. Ethyl 7-phenyl-2-methyleneheptanoate, prepared from the monoester, was oxidized with m-chloroperbenzoic acid to yield ethyl 2-(5-phenylpentyl)oxirane-2-carboxylate 5. The method of radiolabelling, based on the thallation of compound and the subsequent treatment with radioiodide, resulted in a regioselective radioiodination with a 54% radiochemical yield. (author).
Solvothermal synthesis of vanadium phosphate catalysts for n-butane oxidation
2009-01-01
In this paper, we have developed a simple, low-cost, template-free and surfactant-free solvothermal process for synthesis of vanadyl hydrogen phosphate hemihydrate (VOHPO4.0.5H2O) with well defined crystal size. The synthesis was performed by reaction of VPO4.2H2O with an aliphatic alcohol (isobutyl alcohol, 1-pentanol, 1-hexanol, 1-heptanol or 1-decanol). This afforded well crystallized VOHPO4.0.5H2O by solvothermal methods at 120^oC temperature. This new method significantly reduced the preparation time and lowered production temperature (50%) of catalyst precursor (VOHPO4.0.5H2O) when compared to conventional hydrothermal synthesis methods. By varying the reducing agent, the solvothermal evolution process from layered tetragonal phase VOPO4.2H2O to orthorhombic phase VOHPO4.0.5H2O was o...
Solubility and limiting activity coefficient of simvastatin in different organic solvents
2009-01-01
Equilibrium mole fraction solubility of Zocor (simvastatin) a pharmaceutically important compound, was measured between 279 and 315K, in fifteen different industrial-relevant organic solvents including: methyl acetate, ethyl acetate, propyl acetate, iso-propyl acetate, butyl acetate, iso-butyl acetate, sec-butyl acetate, tert-butyl acetate, and ethanol, propanol, 1-butanol, 2-butanol, 1-pentanol, 1-hexanol, and 1-octanol. Fusion enthalpy, DfusH, melting point temperature, Tm, were measured to be 32,169J/mol, 412.6K, respectively; and the difference in the molar heat capacity (at constant pressure) of the liquid, and solid form of simvastatin, DCP, was approximated (by extrapolation) to be 230J/molK. Dissolution of simvastatin was found to be endothermic, and entropically favorable. The act...
2010-01-01
In this paper we report an investigation of the effects of E/N over the range of 90-140Td on the product ions resulting from the reactions of H3O^+ with 12 saturated alcohols using a proton transfer reaction mass spectrometer (PTR-MS). The alcohols included in this study are methanol, ethanol, 1-propanol, 2-propanol, 1-butanol, 2-methyl-1-propanol, 2-methyl-2-propanol, 2-butanol, cyclopentanol, 1-pentanol, cyclohexanol, and 1-hexanol. Only in the cases of methanol and ethanol are any substantial amounts of the protonated parent observed at any E/N. For the other saturated alcohols predominantly fragment ions are observed. This implies that attempts to identify and hence monitor saturated alcohols in trace concentrations in a complex chemical environment using PTR-MS will be fraught with di...
Oil-in-water microemulsion globules as carriers of lipophilic substances across liquid membranes
1983-11-10
The carrier properties of microemulsion droplets were investigated by using biphasic systems of the Winsor I type (constituted of an oil-phase floating on the top of an oil-in-water microemulsion phase). The systems investigated were constituted of sodium dodecyl sulfate/1-pentanol/n-dodecane/ (or brine). The microemulsion was used as a liquid membrane between 2 oil phases (a source phase and a receiving phase) and the rate of transfer of neutral arenes (pyrene, perylene, and anthracene), practically insoluble in the water continuous phase of the microemulsion, was determined from ultraviolet spectrophotometric measurements. The influence of different parameters on the transported solutes was studied: initial concentration of solute in the source phase, composition of the microemulsion, salt concentration. The results are shown to be consistent with a model in which the diffusion of droplets is coupled with a fast solubilization-desolubilization process and other possible mechanisms are critically examined. 32 references.
1987-01-01
The Fischer-Tropsch reaction is a complex combination of many reactions. Among those that have been demonstrated to occur on the catalyst surface are CO dissociation, build-up of carbon chains by a polymerization process, desorption of products such as olefins and oxygen-containing compounds, water formation and its subsequent shift reaction to form CO/sub 2/, olefin hydrogenation, isomerization and reincorporation in the synthesis and, probably, other reactions yet to be identified and studied. The tracer technique, involving the feeding of /sup 14/C-labeled compounds to the synthesis, is being used here in an effort to learn how catalyst additives and supports influence these reactions and determine the final product distribution. The results presented in this paper utilized (1-/sup 14/C)-1-pentanol as the label. Product separations were utilized in order to evaluate the /sup 14/C distribution in alkene and alkane components over a range of carbon numbers. Results pertaining to the two alpha values are presented in this paper. 21 refs., 13 figs.
Graphite furnace-atomic absorption spectrophotometric determination of palladium in soil
2000-08-01
A new and sensitive procedure for the graphite furnace-atomic absorption spectrophotometric (GF-AAS) determination of Pd in soil at nanogram level is described. The method is based on prior separation and enrichment of the metal as Pd(II)-SnCl{sub 3}{sup -}-N-butylacetamide (BAA) complex into 1-pentanol (PN) by solvent extraction method. The value of the molar absorptivity of the complex in three solvents, i.e. ethyl acetate, 1-pentanol, chloroform, lie in the range of (0.70-2.75) x 10{sup 4} L mol{sup -1} cm{sup -1} at {lambda}{sub max} 360-440 nm. The metal could be enriched into organic solvent, i.e. PN, up to 10-folds. The sensitivity (A = 0.0044) of the method in the term of the peak height was 0.5 ng Pd/mL of the aqueous solution at an enrichment factor (EF) of 5. Optimization of analytical variables during enrichment and GF-AAS determination of the metal are discussed. The method has been applied for the analysis of Pd to soil samples derived from roads and highways in Germany. (orig.)
2010-01-01
Solid-liquid phase diagrams (SLE) have been determined for {cholesterol+1-alcohol (1-heptanol, 1-octanol, 1-nonanol, 1-decanol}, or binary solvent mixture {1-alcohol (1-butanol, 1-pentanol, 1-hexanol, 1-heptanol, 1-octanol, 1-nonanol, 1-decanol)+cyclohexane} using a dynamic method at ambient pressure. Simple eutectic systems with complete miscibility in the liquid phase were observed. The solubility increases with an increase in the number of carbon atoms in the 1-alcohol chain length. The temperature of the eutectic points shifts to the lower cholesterol mole fractions as the alkyl chain length of the 1-alcohol decreases. The higher cross-intermolecular interaction was observed for the longer length of an alcohol, especially with 1-decanol. The solubility data in 1-alcohols were compared ...
Determination of absolute photoionization cross-sections of oxygenated hydrocarbons
2010-01-01
The near-threshold absolute photoionization cross-sections of 12 oxygenated hydrocarbons, including 1-butanol, 2-butanol, iso-butanol, tert-butanol, 1-pentanol, tert-pentanol, iso-pentanol, methyl tert-butyl ether (MTBE), ethyl tert-butyl ether (ETBE), furan, 2-methylfuran, 2,5-dimethylfuran, were measured in the photon energy range from respective ionization thresholds to 11.5eV. The experiments were performed with photoionization mass spectrometry and tunable synchrotron vacuum ultraviolet (VUV) light. Binary-liquid-mixtures of the investigated sample and benzene were used in the measurements where benzene acts as a calibration standard, due to its well known photoionization cross-section at the photon energies from its ionization energy (9.24eV) to 11.5eV. Photodissociative fragments fr...
2008-05-15
The densities, {rho} and the speeds of sound, u, for {l_brace}2-(2-hexyloxyethoxy)ethanol (C{sub 6}E{sub 2}) + methanol, +1-propanol, +1-pentanol, and +1-heptanol{r_brace} have been measured as a function of composition using an Anton-Paar DSA 5000 densimeter at temperatures (288.15, 293.15, 298.15, 303.15, and 308.15) K and atmospheric pressure over the whole concentration range. The {rho} and u values were used to calculate excess molar volumes, V{sup E}, and excess molar isentropic compressibility, K{sub S,m}{sup E}, respectively. Also, thermal expansivity, {alpha}, partial molar volume, V-bar{sub i}, and partial molar volume of the components at infinite dilution, V-bar{sub i}{sup 0}, have been calculated. The variation of these properties with composition and temperature of the mixtures are discussed in terms of molecular interactions.
2008-01-01
The densities, rho and the speeds of sound, u, for left brace2-(2-hexyloxyethoxy)ethanol (C6E2) + methanol, +1-propanol, +1-pentanol, and +1-heptanolright brace have been measured as a function of composition using an Anton-Paar DSA 5000 densimeter at temperatures (288.15, 293.15, 298.15, 303.15, and 308.15) K and atmospheric pressure over the whole concentration range. The rho and u values were used to calculate excess molar volumes, VE, and excess molar isentropic compressibility, KS,mE, respectively. Also, thermal expansivity, alpha, partial molar volume, V-bari, and partial molar volume of the components at infinite dilution, V-bari0, have been calculated. The variation of these properties ...
Binary mutual diffusion coefficients of aqueous alcohols. Methanol to 1-heptanol
1996-03-01
Mutual diffusion coefficients, measured by Taylor dispersion at 25 C, are reported for binary aqueous solutions of methanol, ethanol, isomeric propanols and butanols, 1-pentanol, 1-hexanol, and 1-heptanol. Limiting diffusion coefficients (D{sup 0}) for the 1-alkanols are found to decrease with alcohol molar volume V approximately as V{sup {minus}1/2}. Although values of D{sup 0} for aqueous 1-propanol and 2-propanol are nearly identical within experimental error, the limiting diffusion coefficients of the isomeric butanols differ by up to 10% and increase in the order D{sup 0}(2-methyl-2-propanol) < D{sup 0}(2-butanol) {approx} D{sup 0}(2-methyl-1-propanol) < D{sup 0}(1-butanol). The butanol results illustrate the difficulty of predicting accurate diffusion coefficients for aqueous solutions.
An investigation on ion association and ion solvation of potassium acetate in alcohol solutions
2009-01-01
The molar conductivities (Λ) of potassium acetate in methanol (MeOH), ethanol (EtOH), 1-propanol (PrOH), 2-propanol (isoPrOH), 2-methyl-1-propanol (MPrOH), 1-butanol (BuOH), 1-pentanol (PeOH), and benzyl alcohol (BeOH) were measured at 293.15 K. The concentration dependence of Λ was analysed by means of the Lee-Wheaton conductivity equation in the form proposed by Pethybridge and Taba. From the analysis of the experimental Λ values, the limiting molar conductivities (Λo) and the association equilibrium constants (κα) were determined. The centre-to-centre distance (a) of the formed ion pairs were assumed to be equal to the Bjerrum's distance of closest approach. Furthermore, the ultrasonic velocities (u) and the densities (ρ) were measured in order ...
The preparation of ester enantiomers (acetates, butanoates, hexanoates and octanoates) of the secondary alcohols 2-pentanol, 2-heptanol and 2-nonanol via lipase-catalyzed kinetic resolutions was investigated. Conversion rates and stereochemical courses of esterification and hydrolysis reactions catalyzed by commercially available enzyme preparations were followed for the homologous series of these passion fruit-typical 2-alkyl esters by capillary gas chromatography using heptakis(2,3-di-O-methyl-6-O-tert-butyldimethylsilyl)-beta-cyclodextrin as chiral stationary phase. An efficient method was developed to prepare the ester enantiomers via lipase-catalyzed esterifications: optically pure (R)-2-alkyl esters (ee > 99.9%) were obtained by esterification of the racemic alcohols with enantioselective Candida antarctica lipase B (immobilized) as catalyst. The subsequent esterification of the unreacted alcohols using lipase from Candida cylindracea yielded the optically enriched (S)-esters (ee > 81.4%). The separation of the products via liquid solid chromatography using a mixture of silica gel and aluminum oxide (basic) resulted in high chemical purities and yields (> 40 mol %).
Mechanistic studies of the pathways leading to ethers via coupling of alcohols
The reaction mechanisms for the solid acid-catalyzed dehydrative coupling of methanol and ethanol with isobutanol and 2-pentanol to form ethers were examined by using isotope labelling and chiral inversion experiments. When the reactions were carried out it 110{degrees}C and 1 MPa with {sup 18}O-ethanol and {sup 16}O-isobutanol over the Amberlyst-35 resin catalyst, 95% of the major product ethyl isobutyl ether (EIBE) contained {sup 16}O, while 96% of the minor product ethyl tertiarybutyl ether (ETBE) contained {sup 18}O. Similar results were obtained with methanol and isobutanol over Nafion-H and Amberlyst-35 catalysts, with methyl isobutyl ether (MIBE) and methyl tertiarybutyl ether (MTBE) as the products. These results indicate that EIBE (MIBE) was produced by a surface-catalyzed S{sub N}2 reaction, while the ETBE (MTBE) product arose via a carbenium intermediate. The analogous reaction carried out over Nafion-H and HZSM-5 catalysts with chiral 2-pentanol verified the surface-mediated S{sub N}2 reaction, wherein chiral inversion of the product ether was observed relative to the S- and R-2-pentanol reactants.
Mechanistic studies of the pathways leading to ethers via coupling of alcohols
1995-12-31
The reaction mechanisms for the solid acid-catalyzed dehydrative coupling of methanol and ethanol with isobutanol and 2-pentanol to form ethers were examined by using isotope labelling and chiral inversion experiments. When the reactions were carried out it 110{degrees}C and 1 MPa with {sup 18}O-ethanol and {sup 16}O-isobutanol over the Amberlyst-35 resin catalyst, 95% of the major product ethyl isobutyl ether (EIBE) contained {sup 16}O, while 96% of the minor product ethyl tertiarybutyl ether (ETBE) contained {sup 18}O. Similar results were obtained with methanol and isobutanol over Nafion-H and Amberlyst-35 catalysts, with methyl isobutyl ether (MIBE) and methyl tertiarybutyl ether (MTBE) as the products. These results indicate that EIBE (MIBE) was produced by a surface-catalyzed S{sub N}2 reaction, while the ETBE (MTBE) product arose via a carbenium intermediate. The analogous reaction carried out over Nafion-H and HZSM-5 catalysts with chiral 2-pentanol verified the surface-mediated S{sub N}2 reaction, wherein chiral inversion of the product ether was observed relative to the S- and R-2-pentanol reactants.
Synthesis and structures of zinc alkoxo, aryloxo and hydroxo complexes with an amidodiamine ligand
2010-01-01
The synthesis and characterization of zinc complexes bearing an amidodiamine ligand, (EtO)4Zn3[N(CH2CH2NMe2)2]2 (1), [(Et3CO)ZnN(CH2CH2NMe2)2]2 (2) and [(2,6-iPr2C6H3O)ZnN(CH2CH2NMe2)2]2 (3), [(Me3Si)2N]Zn[N(CH2CH2NMe2)2] (4) and [(Me3Si)2N]2Zn2(OH)[N(CH2CH2NMe2)2] (5), are reported. Compounds 1-3 are synthesised in the reactions of {Zn[N(CH2CH2NMe2)2]2}2 with 2equiv. of ethanol, 3-ethyl-3-pentanol and 2,6-diisopropylphenol, respectively. Compound 4 is obtained by the reaction of Zn[N(SiMe3)2]2 with HN(CH2CH2NMe2)2, and compound 5 is synthesised by reacting 4 with 1equiv. of H2O. Compound 4 is characterized by NMR and MS while all of the other compounds are characterized with NMR, MS, elemental analysis and single-crystal X-ray diffraction. Compound 1 is a trinuclear species containing a Z...
Yields and decay kinetics of the solvated electron in pulse radiolysis of 1-alkanols
1983-01-01
The products of the yields of the solvated electron in 1-alkanols, G(e/sup -/sub(alk)), and the extinction coefficient of e/sup -/sub(alk) at its absorption maximum, epsilon(e/sup -/sub(alk)) sub(max), relative to the same product for the hydrated electron, G(e/sup -/sub(aq))epsilon(e/sup -/sub(aq))sub(max), for a 60 nsec irradiation at room temperature are given in parentheses after the name of each 1-alkanol: methanol (0.38), ethanol (0.42), 1-propanol (0.33), 1-butanol (0.30), 1-pentanol (0.28), 1-hexanol (0.31), 1-heptanol (0.27), 1-octanol (0.29), 1-nonanol (0.26), and 1-decanol (0.24). The decay kinetics of e/sup -/sub(alk) after 60 or 400 nsec of pulse irradiation of 1-alkanols, C/sub 1/-C/sub 10/, fit competitive pseudo-first order and second order (initial concentrations of both reactants the same) processes. Except for 1-propanol to 1-pentanol, the observed second order specific rates are a function of the dose per pulse. A mechanism is proposed for the above given decay kinetics of e/sup -/sub(alk) in C/sub 1/-C/sub 10/ 1-alkanols.
Temperature dependence of the volumetric properties of some alkoxypropanols + n-alkanol mixtures
2004-03-01
The excess molar volumes V{sub m}{sup E} for binary liquid mixtures containing dipropylene glycol monomethyl ether or dipropylene glycol monobutyl ether and methanol, 1-propanol, 1-pentanol and 1-heptanol have been measured as a function of composition using a continuous dilution dilatometer at T=(288.15, 298.15, and 308.15) K and atmospheric pressure over the whole concentration range. The excess volume results allowed the following mixing quantities to be reported in all range of concentrations or at equimolar concentrations: {alpha}, volume expansivity; ({partial_derivative}V{sub m}{sup E}/{partial_derivative}T){sub p}; ({partial_derivative}H{sup E}/{partial_derivative}P){sub T} at T=298.15 K. The obtained results have been compared at T=298.15 K with the calculated values by using the Flory theory of liquid mixtures. The theory predicts the {alpha}, and {alpha}{sup E} values rather well, while the calculated values of ({partial_derivative}V{sub m}{sup E}/{partial_derivative}T){sub p} and ({partial_derivative}H{sup E}/{partial_derivative}P){sub T} show general variation with the alkyl chain length of the alkoxypropanols. The results are discussed in terms of order or disorder creation.
2008-01-01
A thermostable alcohol dehydrogenase (ADH-I) isolated from the potential thermophilic ethanologen Geobacillus thermoglucosidasius strain M10EXG has been characterised. Inverse PCR showed that the gene (adhI) was localised with 3-hexulose-6-phosphate synthase (HPS) and 6-phospho-3 hexuloisomerase (PHI) on its genome. The deduced peptide sequence of the 1020-bp M10EXG adhI, which corresponds to 340 amino acids, shows 96% and 89% similarity to ADH-hT and ADH-T from Geobacillus stearothermophilus strains LLD-R and NCA 1503, respectively. Over-expression of M10EXG ADH-I in Escherichia coli DH5α (pNF303) was confirmed using an ADH activity assay and SDS-PAGE analysis. The specific ADH activity in the extract from this recombinant strain was 9.7(±0.3) U mg-1 protein, compared to 0.1(±0.01) U mg-1 protein in the control strain. The recombinant E. coli showed enzymatic activity towards ethanol, 1-butanol, 1-pentanol, 1-heptanol, 1-hexanol, 1-octanol and 2-propanol, but not methanol. In silico analysis, including phylogenetic reconstruction and protein modeling, confirmed that the thermostable enzyme from G. thermoglucosidasius is likely to belong to the NAD-Zn-dependent family of alcohol dehydrogenases. Publisher: Netherlands: Elsevier BV Relation: Journal of Biotechnology Other identifier: URN:ISSN:0168-1656
The methyl, ethyl, propyl and butyl esters of vegetable and tree oils are effective solvent extractants for 1-butanol from aqueous solution. Early applications of this process will probably involve bacterial mixed solvent fermentations of relatively impure waste and low-valued carbohydrates. Two types of materials, salts and solvents, could be expected to affect the extraction of 1-butanol from such industrial fermentation systems. The effect of four salts, three alcohols, and a ketone were evaluated using factorial experiments. Variations in NaCl, Na2SO4, Na2SO3, and KHPO4 from 0 to 0.15 M on the extraction of 0.1 to 4.1% 1-butanol from aqueous solutions at 25, 40, and 55 C gave small changes in distribution coefficient. Mild in creases occurred with increasing temperature and increasing NaCl, Na2SO4, and KH2PO4. Mild decreases in 1-butanol extraction occurred with increasing Na2SO3. Variations in acetone, ethanol, and 2-propanol concentrations ranging between 0 and 4% w/v at 25, 40 and 55 C gave small changes in distribution coefficient at 1-butanol concentrations ranging between 0.1 and 4.1% w/v had little effect. A slight increase in 1-butanol extraction was observed with increasing 1-pentanol under similar conditions.
2006-02-15
Speeds of sound u, isentropic compressibilities {kappa}{sub S}, viscosities {eta}, excess isentropic compressibilities {kappa}{sub S}{sup E}, excess molar volumes V{sub m}{sup E}, excess viscosities {eta}{sup E}, and excess Gibbs energy of activation {delta}G{sup *E} of viscous flow have been investigated for seven binary mixtures of methylcyclohexane (MCH) with ethanol, 2-propanol, 2-butanol, 2-pentanol, 2-hexanol, 2-heptanol, and 2-octanol at 298.15K. Excess properties were calculated therefrom and were correlated by Redlich-Kister type function in terms of mole fractions. For mixtures of MCH with used 2-alkanols, over the entire range of mole fractions, V{sub m}{sup E} is positive and both {eta}{sup E} and {delta}G{sup *E} are negative. The {kappa}{sub S}{sup E} values are large and positive over the entire range of composition for mixtures of MCH with ethanol, 2-propanol, 2-butanol and for mixtures of MCH with 2-pentanol, 2-hexanol, 2-heptanol and 2-octanol change sign from positive in the 2-alkanol rich regions to negative in MCH rich regions. These results are consistent with the self-association of 2-alkanols and the nonpolar character of MCH, which produces the dissociation of the 2-alkanols. The viscosity, speeds of sound and isentropic compressibility data have been correlated with the various equations.
Mechanistic studies of the pathways leading to ethers via coupling of alcohols
1995-12-01
The reaction mechanisms for the solid acid-catalyzed dehydrative coupling of methanol and ethanol with isobutanol and 2-pentanol to form ethers were examined by using isotope labelling and chiral inversion experiments. When the reactions were carried out at 110{degrees}C and 1 MPa with Et{sup 18}OH and {sup 16}O-isobutanol over Amberlyst-35, 95% of the major product ethyl isobutyl ether (EIBE) contained {sup 16}O, while 96% of the minor product ethyl tertiarybutyl ether (ETBE) contained {sup 18}O. Similar results were obtained with methanol and isobutanol over Nafion-H and Amberlyst-35 catalysts, with MIBE and MTBE as the products. These results indicate that EIBE (MIBE) was produced by a surface-catalyzed S{sub N}2 reaction, while the ETBE (MTBE) product arose via a carbenium intermediate. The analogous reactions carried out over Nafion-H and H-ZSM-5 catalysts with chiral 2-pentanol verified the surface-mediated S{sub N}2 reaction, where in chiral inversion of the product ether was observed relative to the S- and R-2-pentanol reactants. In addition, a remarkable shape selectivity with chiral inversion was observed over the H-ZSM-5 zeolite to selectively form 2-ethoxypentane but not 3-ethoxypentane.
2010-01-01
A headspace-solid-phase micro-extraction–gas chromatography–mass spectrometry (HS-SPME–GC–MS) method has been developed to quantify a range of volatile compounds in Hunter Valley Semillon wines. The fibre selected for the method was a 50/30 μm divinylbenzene/carboxen/polydimethylsiloxane fibre, a three-phase fibre that allows extraction and desorption of a wide range of volatile compounds of different chemical functionalities and polarities. Four internal standards, methyl isobutyl ketone, n-dodecane, 4-methyl-2-pentanol and ethyl nonanoate were used to monitor the SPME fibre extraction efficiency and integrity. Fibre integrity was monitored by plotting the ratio of the peak area for each internal standard divided by the sum of the peak area for all internal standards as a function of analysis number. The advantage of using four internal standards for better quality control of the fibre integrity is described. The identity of twenty-one volatile compounds was ascertained by comparison of their chemical characteristics (retention indices, mass spectra) with reference compounds using two columns of different polarities. Quantification was achieved using calibration curves constructed for each compound with linear regression equations having correlation coefficients (R2) ranging from 0.9717 to 0.9999. The method was applied to two Semillon wines (recent vintage and aged) representative of the Hunter Valley styles. As is typical of white wines, 3-methyl-1-butanol was quantified as the most concentrated volatile compound (83 and 66 mg L−1 for the 2006 and the 1996 wines, respectively). The study highlights the use of well-defined procedures to ensure integrity of quantitative data where several fibres may be required during an extended study over one or more vintages. Publisher: Netherlands: ELSEVIER Relation: Analytica Chimica Acta Other identifier: URN:ISSN:0003-2670
An efficient and general method for the synthesis of reduced polypropionates has been developed through the application of asymmetric carboalumination of alkenes catalyzed by dichlorobis(1-neomenthylindenyl)zirconium [(NMI)2ZrCl2]. In this investigation, attention has been focused on those reduced polypropionates that are α-monoheterofunctional and either ω-ethyl or ω-n-propyl. The reaction of 3-buten-1-ol with triethylaluminum (Et3Al) or tripropylaluminum (nPr3Al) in the presence of (NMI)2ZrCl2 and isobutylaluminoxane gave, after protonolysis, (R)-3-methyl-1-pentanol as well as (R)- and (S)-3-methyl-1-hexanols in 88–92% yield in 90–92% enantiomeric excess in one step. These 3-monomethyl-1-alkanols were then converted to two stereoisomers each of 2,4-dimethyl-1-hexanols and 2,4-dimethyl-1-heptanols via methylalumination catalyzed by (NMI)2ZrCl2 and methylaluminoxane followed by oxidation with O2. The four-step (or three-isolation-step) protocol provided syn-2,4-dimethyl-1-alkanols of ≥98% stereoisomeric purity in ≈50% overall yields, whereas (2S,4R)-2,4-dimethyl-1-hexanol of comparable purity was obtained in 40% overall yield. Commercial availability of (S)-2-methyl-1-butanol as a relatively inexpensive material suggested its use in the synthesis of (2S,4S)- and (2R,4S)-2,4-dimethyl-1-hexanols via a three-step protocol consisting of (i) iodination, (ii) zincation followed by Pd-catalyzed vinylation, and (iii) Zr-catalyzed methylalumination followed by oxidation with O2. This three-step protocol is iterative and applicable to the synthesis of reduced polypropionates containing three or more branching methyl groups, rendering this method for the synthesis of reduced polypropionates generally applicable. Its synthetic utility has been demonstrated by preparing the side chain of zaragozic acid A and the C11–C20 fragment of antibiotics TMC-151 A–F.
Tritium, {sup 3}H, is one of the hydrogen isotopes, created in coolant of a fission reactor and to be utilized as fuel for nuclear fusion reactors. Since a large amount of tritium will be contained in a fusion reactor or in a fission reactor, a small fraction of the tritiated chemical species, in most cases, tritiated water, may leak to the environment. Tritium is, however, a radioactive isotope whose specific radioactivity is 4 x 10{sup 17} Bq kg{sup -1}, and easy to transfer in human body, its confinement is very important from the safety aspect. One of the problems of tritium confinement and decontamination of tritiated chemical species is related with necessity of its isotope separation from lighter hydrogen isotopes, {sup 2}H and {sup 1}H. Most of principles for the isotope separations are based on fractionations of isotopes in different chemical species. A large fractionation for hydrogen isotopes is observed in a chemical exchange of hydrogen atoms between water, Q{sub 2}O, and hydrogen gas, Q{sub 2}, where 'Q' denotes one of the hydrogen isotopes. Heavier isotopes are enriched significantly into Q{sub 2}O rather than Q{sub 2}. Therefore practical method of tritium removal would be established by hydrogen isotope separation with chemical exchange of water and hydrogen gas. At first, we prepared a catalyst, by reducing Pt{sup 4+} in reversed micelles where the reducing agent, aqueous solution of sodium tetra borohydrate, NaBH{sub 4} was also contained in reversed micelles prepared separately. In this situation, micelles containing Pt{sup 4+} and reducing reagent collided and produced Pt nanoparticles, which were expected to be impregnated in the hydrophobic structure after depressurization. After this type of earlier experiment we determined a mass of impregnated Pt by total dissolution of gauze with aqua regia followed by concentration measurement of Pt with ICP-AES. We performed several trials, unfortunately, however, the mass of Pt deposited on the gauze was very small to detect, and this approach turns to be not successful. As the second approach, we utilize CO{sub 2} soluble Pt precursor, CODMe{sub 2}Pt purchased from Sigma-Aldrich Co. and H{sub 2} gas as reducing agent, which could be completely mixed with SC-CO{sub 2}. This system was well-known for Pt particle formation by auto-catalytic growth. The second approach was aiming at increasing Pt amount deposited in the gauze. This approach was successful in increasing Pt amount, but the Pt particle size also increased to be more than 50 nm, which was not suitable for catalyst. Finally, we synthesized the catalyst by the following procedure: firstly, a reducing agent of NaBH{sub 4} was deposited on the nano-textured hydrophobic layer on the gauze. This step was realized by forming reversed micelles of aqueous NaBH{sub 4} solution using a surfactant AOT and a co-surfactant 2,2,3,3,4,4,5,5,-octafluoro-1-pentanol (F-pentanol) in SC-CO{sub 2}. This system of surfactant combination of AOT and F-pentanol has been found to work successfully in recent studies. In the second step, the gauze was contacted with CODMe{sub 2}Pt dissolved in SC-CO{sub 2} to synthesize seeds of Pt particles for the auto-catalytic reaction proceeding by CODMe{sub 2}Pt with hydrogen. The seeds were formed by the reaction between deposited NaBH{sub 4} and CODMe{sub 2}Pt in SC-CO{sub 2}. The physical characterization of this catalyst was performed by SEM-EDS. By this procedure, the Pt hydrophobic catalyst where Pt nanoparticle of 10 nm in diameter was locally deposited in the nano-textured layer was successfully prepared. Hydrophobicity after the chemical Pt deposition was tested by measurement of water absorbed on the gauze and the catalyst performance was evaluated by {sup 1}H{sup 2}H formation through the scrambling reaction from {sup 1}H{sub 2} and {sup 2}H{sub 2} and the reaction was successfully observed. We demonstrated a new hydrophobic catalyst preparation using SC-CO{sub 2} effectively. We can conclude that the approach of creating Pt nanoparticles in SC-CO{sub 2} and depositing them in the super-hydrophobic structure on the metal surface is useful for synthesizing hydrophilic catalysts for the hydrogen isotope separation.
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