Showing papers on "Hexane published in 1997"
TL;DR: In this paper, a waveguide technique has been employed to determine the refractive indices of the plasma polymer films in the visible and near infrared regions of the dielectric spectrum.
156 citations
TL;DR: In this paper, the authors present experimental values of the density, refractive index, speed of sound, and dynamic viscosity of the binary mixtures (methanol, ethanol or 1-propanol) with (n-pentane, n-hexane, N-heptane, and n-octane) at 298.15 K and atmospheric pressure, as a function of the molar fraction.
149 citations
TL;DR: A theoretical model is presented to describe the adsorption of surfactant molecules at the water/oil interface for the case when transport across the interface must be considered due to the solubility of the Surfactant in both liquid phases.
98 citations
TL;DR: In this paper, the surface tension of the aqueous surfactant solution after equilibration with the second liquid phase was measured to determine the partition coefficient between water and hexane of some n-alkyldimethylphosphine oxides and octylphenyl poly(ethylene glycol) ethers.
Abstract: The partition coefficients between water and hexane of some n-alkyldimethylphosphine oxides (CnDMPO) and octylphenyl poly(ethylene glycol) ethers (Triton X-100 and Triton X-405) and of one poly(oxyethylene) cetyl ether (C16E20) have been determined by using an indirect technique based on the measurement of the surface tension of the aqueous surfactant solution after equilibration with the second liquid phase. Though some of the surfactants studied have been described in the past as insoluble in alkanes, the results show that at monomeric concentrations, most of them have a non-zero value of the partition coefficient. These results are particularly important when dynamics adsorption phenomena at liquid−liquid interfaces are concerned.
74 citations
TL;DR: There are very small variations in lambda max for all four carotenoids between hexane and methanol, due to differences in molar extinction coefficients.
72 citations
TL;DR: The enantiomeric excess of reductions of keto esters with baker's yeast (Saccharomyces cerevisiae) can conveniently be altered in organic solvents such as diethyl ether, toluene, hexane and ethyl acetate, when compared to corresponding transformations in water as mentioned in this paper.
65 citations
TL;DR: A simple and rapid method for the determination of 13 organophosphorus insecticides and the metabolites in olive oil by GC is described in this paper, where the pesticide was extracted from oil with acetonitrile and no cleanup was needed.
53 citations
TL;DR: In this article, the catalytic effects of a sulfated zirconium oxide and a platinum-sulfated zirconium oxide during the isomerization of hexane are described.
39 citations
Patent•
15 May 1997
TL;DR: In this paper, a process of treating an oil, the process comprising contacting the oil with a polar solvent to extract at least one compound that is soluble in the solvent, and then separating the solvent containing the compound from the so treated oil, is described.
Abstract: The present invention relates to a process of treating an oil, the process comprising contacting the oil with a polar solvent to extract at least one compound that is soluble in the solvent, and then separating the solvent containing the compound from the so treated oil. The oil is microbially derived, and extracted either from a fermentation broth or a filtrate thereof using hexane. The compound to be extracted is usually a sterol or a diglyceride. The solvent is ethanol having up to 5 % water. The oil can contain a polyunsaturated fatty acid such as C18, C20 or C22 φ-3 or φ-6 fatty acid, such as arachidonic acid.
33 citations
TL;DR: In this article, a ternary diagram of waste oil/basic organic component/polar compound containing 3 g/L KOH where the phase envelope and the curves of constant sludge removal are plotted are plotted.
Abstract: Waste lubricating oils may be re-refined with organic solvents that dissolve base oil and segregate the additives and solid particles. The present paper emphasizes the composition effect on the efficiency of a ternary solvent composed by n-hexane/2-propanol/1-butanol. Using the ternary diagram of waste oil/basic organic component/polar compound containing 3 g/L KOH where the phase envelope and the curves of constant sludge removal are plotted, it is proposed the composition of 0.25 waste oil/0.35 n-hexane/0.40 polar compound (80% 2-propanol + 20% 1-butanol, with 3 g/L KOH) for the process. A contribution for the understanding of polymethacrylate flocculation supported on infrared spectra is given.
32 citations
TL;DR: Lipase from Candida rugosa immobilized on a nylon support has been used to synthesize lovastatin by the regioselective acylation of a diol lactone precursor with 2-methylbutyric acid in mixtures of organic solvents.
Abstract: Lipase from Candida rugosa immobilized on a nylon support has been used to synthesize lovastatin, a drug which lowers serum cholesterol levels, by the regioselective acylation of a diol lactone precursor with 2-methylbutyric acid in mixtures of organic solvents. Analogs of lovastatin having a different side chain were also obtained through this method by reacting the diol substrate with different carboxylic acids. The selection of reaction conditions that maximize the initial reaction rate is investigated. Since the diol substrate has very low solubility in non-polar solvents, reaction solvents consisting of mixtures of hexane with a different, more polar cosolvent are considered. For each of the cosolvent mixtures studied, the reaction rate is maximum for an intermediate percentage of cosolvent in hexane. With total concentrations of the diol lactone in the range 6.25-12.5 mM, maximum initial rates correspond approximately to those cosolvent concentrations that permit a complete solubilization of the substrate. At higher cosolvent concentrations, lower rates are obtained. When considering the same dissolved substrate concentration, the reaction rate was found to increase with increasing values of logP(mix) and decreasing values of the dielectric constant, when varying the composition of a binary solvent mixture. However, when comparing different cosolvents, no general trend with respect to these properties was observed. (c) 1997 John Wiley & Sons, Inc. Biotechnol Bioeng 56:671-680, 1997.
TL;DR: Isoamyl acetate was synthesised in high yields (>90%) via lipase catalysed acylation of the corresponding alcohol by ammonium acetate in supercritical carbon dioxide (SCCD) and by acetic acid in hexane.
TL;DR: In this article, an isosteric method was used to determine the adsorption equilibrium of hexane in silicalite-1 from 333 K to 423 K, and loadings of 2.8 to 5.5 molecules per unit cell.
TL;DR: In this paper, the abilities of two association models to predict anthracene solubilities in a number of binary alkane + alcohol solvent mixtures are compared, and the Kretschmer-Wiebe and mobile order models were obtained from binary VLE data.
TL;DR: The interaction of hydrocarbon chains at aqueous interfaces is a major factor in defining the interfacial structures of monolayers and membranes formed by surfactants as mentioned in this paper, and the intermolecular pair poten...
Abstract: The interaction of hydrocarbon chains at aqueous interfaces is a major factor in defining the interfacial structures of monolayers and membranes formed by surfactants. The intermolecular pair poten...
TL;DR: In this article, the authors measured the excess molar volumes for binary mixtures of butanol (n-C4H9OH) + pentane, hexane, heptane, octane, and carbon tetrachloride (CCl4) at both temperatures 288.15 K and 298.15K.
Abstract: Excess molar volumes, have been measured for binary mixtures of butanol (n-C4H9OH) + pentane (n-C5H12), + hexane (n-C6H14), + heptane (n-C7H16), + octane (n-C8H18), + 2,2,4-trimethylpentane (2,2,4-TMP), and + carbon tetrachloride (CCl4) at 288.15 K and 298.15 K, and refractive indexes, nD, have been measured for these mixtures at 298.15 K. At both temperatures has been found to be positive throughout the entire range of composition for xn-C4H9OH + (1 − x)n-C7H16 and + (1 − x)n-C8H18. At both temperatures 288.15 K and 298.15 K, is positive at low mole fractions of n-C4H9OH and negative at its higher mole fractions in the case of mixtures of n-C4H9OH with n-C5H12, n-C6H14, 2,2,4-TMP, and CCl4. Values of and nD for the various mixtures of n-C4H9OH have been fitted in smoothing equations.
TL;DR: In this paper, the incorporation of TS-1 and Ti-MCM-41 catalysts in PDMS is proven to enable the oxidation of hexane and epoxidation of C-cyclooctene.
TL;DR: The reaction of indium(I) bromide with α,ω-alkanediylbis(bromomercury) complexes (alkane = butane, pentane, and hexane) resulted in formation of the corresponding α, δ-alkane-βromoindium compounds, which were isolated as THF adducts as discussed by the authors.
TL;DR: In this article, the equilibrium relationship in the extraction process that was developed in a research laboratory for the treatment of canola were studied, where hexane is used as well as CH3OH that contains 5% (vol/vol) H2O and 0.08% (w/w) NaOH to simultaneously produce improved meal and high quality oil.
Abstract: The equilibrium relationships in the extraction process that was developed in our research laboratory for the treatment of canola were studied. In the process, hexane is used as well as CH3OH that contains 5% (vol/vol) H2O and 0.08% (w/w) NaOH to simultaneously produce improved meal and high-quality oil. Equilibrium data for canola oil in the hexane-CH3OH/H2o/NaOH, meal-hexane, and meal-CH3OH/H2O/NaOH-hexane systems are reported. A high partition coefficient for oil between hexane and the polar phase provided a large driving force for mass transfer. The presence of the CH3OH phase improved oil extraction, probably by rupturing the cell structure. The process proved to be a somewhat less desirable replacement for CH3OH/H2O/NH3 extraction and recovered 93.5% of the oil and 91.8% of the protein in the seed, while with CH3OH/H2O/NH3, the oil and protein recoveries were 96.8 and 94.0%, respectively. The NaOH treatment removed only 50.2% of the glucosinolates, and some of the oil was hydrolyzed by the NaOH, making the process less effective, despite its simplicity.
TL;DR: Kinematic viscosities ν have been measured for binary liquid mixtures of butanol (n-C4H9OH) + pentane (n −C5H12), + hexane (N −C6H14), + heptane ( n −C7H16), and + octane(n -C8H18) at T = 298.15 K as mentioned in this paper.
Abstract: Kinematic viscosities ν have been measured for binary liquid mixtures of butanol (n-C4H9OH) + pentane (n-C5H12), + hexane (n-C6H14), + heptane (n-C7H16), and + octane (n-C8H18) at T = 298.15 K. Val...
TL;DR: In this paper, the reproducible separation of ten compounds with gradient elution was shown for solvents of low and moderate polarity, such as hexane and dichloromethane.
TL;DR: In this paper, the vapor-liquid equilibrium at 94 kPa has been determined for the binary systems of methyl 1,1-dimethylethyl ether (MTBE) with hexane and with heptane.
Abstract: The vapor-liquid equilibrium at 94 kPa has been determined for the binary systems of methyl 1,1-dimethylethyl ether (MTBE) with hexane and with heptane. Both systems deviate slightly from ideal behavior, can be described as regular solutions, and do not present an azeotrope. The activity coefficients and boiling point of the solutions were correlated with its composition by the Redlich-Kister, Wohl, Wilson, UNIQUAC, NRTL, and Wisniak-Tamir equations.
TL;DR: In this article, the UNIQUAC equation was used for predicting ternary VLE data with an inclined ebulliometer at the temperature 308.15 k, 318.15 K, and 101.33 kPa.
TL;DR: In this paper, the excess molar volume data for mixtures containing hexane with three edible oils: olive, corn, and pip of grape have been determined from density measurements at various temperatures between 298.15 and 313.15 K using a vibrating tube densimeter.
Abstract: Excess molar volume data for mixtures containing hexane with three edible oils: olive, corn, and pip of grape have been determined from density measurements at various temperatures between 298.15 and 313.15 K using a vibrating tube densimeter. Results have been correlated by the Redlich−Kister equation. Systems showed negative deviations from ideality in the whole composition range.
TL;DR: In this article, the authors used the Redlich−Kister, NRTL, Wilson, UNIQUAC, and Wisniak−Tamir equations to predict the activity coefficients of the ternary system from those of binary systems.
Abstract: Vapor−liquid equilibrium at 94 kPa has been determined for the systems hexane + heptane and methyl 1,1-dimethylethyl ether (MTBE) + hexane + heptane. The binary system exhibits regular, almost ideal behavior, and no azeotrope is present in the ternary system. The data were correlated by the Redlich−Kister, NRTL, Wilson, UNIQUAC, and Wisniak−Tamir equations and the appropriate parameters are reported. The models allow prediction of the activity coefficients of the ternary system from those of the pertinent binary systems.
TL;DR: In this paper, the hexane + squalane (2,6,10,15,19,23-hexamethyltetracosane) system at (469.8, 524.3, 574.6, and 623.3) K and at pressures ranging from (5.5 to 54.8) bar were measured.
Abstract: Vapor and liquid equilibrium compositions have been measured for the hexane + squalane (2,6,10,15,19,23-hexamethyltetracosane) system at (469.8, 524.3, 574.6, and 623.3) K and at pressures ranging from (5.5 to 54.8) bar. A continuous-flow apparatus was used both to minimize squalane degradation and to measure the lower squalane concentrations in the vapor phase. Mixture critical pressures and compositions were also obtained.
TL;DR: In this paper, the authors presented a method for the disentalization of DITHIOLANES with FERRIC NITRATE and SILICA GEL in HEXANE.
TL;DR: In this article, the cracking of n-hexane at different temperatures over H-ZSM-48 was analyzed using an established kinetic model, which includes a monomolecular cracking path based on Langmuir adsorption isotherm as well as a bimolecular path following rideal kinetics.
Abstract: The cracking of n -hexane at different temperatures over H-ZSM-48 has been analyzed using an established kinetic model. The model includes a monomolecular cracking path based on Langmuir adsorption isotherm as well as a bimolecular path following Rideal kinetics which accounts for the possibility of a chain mechanism being involved. Catalyst decay is accounted by using a time on stream decay function. The scrutiny of the optimal parameters for the model describing n -hexane conversion suggests that the catalyst surface composition is sensitive to temperature owing to the difference in the enthalpy of adsorption between the reactant and the average product of the cracking. As the temperature increases, the reactant competes more successfully for the active sites. The average activation energy for protolytic cracking of n -hexane on H-ZSM-48 was found to be 20.2 kcal mol −1 . Steric inhibition during hydrogen transfer between n -hexane and C 4 and C 3 olefins is also observed.
TL;DR: In this paper, the influence of various reaction parameters such as temperature, WHSV and H2 ton-C6 molar ratio on n-hexane cracking at atmospheric pressure over ZSM-48 has been studied.
Abstract: The influence of various reaction parameters such as temperature, WHSV and H2 ton-C6 molar ratio onn-hexane cracking at atmospheric pressure over ZSM-48 has been studied. The influence of SiO2/Al2O3 variations and isomorphous substitution by Ga and Fe has also been investigated. A linear relationship between the specific catalytic activity for the cracking ofn-hexane and the concentration of strong acid sites has been found.