Showing papers on "Hexane published in 1992"
TL;DR: In this article, a novel experimental apparatus was used to measure hexane, acetone, water, hexane/water, and acetone/water isotherms on BPL activated carbon.
Abstract: A novel experimental apparatus is used to measure hexane, acetone, water, hexane/water, and acetone/water isotherms on BPL activated carbon. Isotherms for pure components are measured from 25 to 125°C with hydrocarbon pressures varied by a factor of 10 7 , from low values to saturation. Emphasis is placed on measuring the hysteresis loop in the water and hydrocarbon/water systems. For adsorption of pure water, the location and size of the hysteresis loop is found to be temperature dependent, with the loop shifting toward higher relative pressures and narrowing as temperature is increased. For the hydrocarbon/water mixtures, the hydrocarbon loading is held constant and water isotherms are measured at 25 and 100°C. The partial pressure of the hydrocarbon is found to increase dramatically at constant hydrocarbon loading as the water loading is increased. Also, hysteresis is observed in the hydrocarbon partial pressure depending on whether the system is on the adsorption or desorption branch of the water isotherms. Behavior is complex and is interpreted qualitatively
128 citations
Patent•
10 Aug 1992TL;DR: In this article, a Ziegler-Natta type suitable for producing ethylene copolymers having a reduced hexane extractable content comprising an organoaluminum component and a titanium trichloride component was presented.
Abstract: A catalyst system of the Ziegler-Natta type suitable for producing ethylene copolymers having a reduced hexane extractable content comprising (a) an organoaluminum component and (b) a titanium trichloride component which has been prepared by reducing titanium tetrachloride with magnesium metal.
121 citations
TL;DR: In this article, the surface tension of normal pentane, hexane, heptane, octane, and octane was investigated with a differential capillary-rise method.
Abstract: New experimental results are reported for the surface tension of normal pentane, hexane, heptane, and octane. The data were obtained with a differential capillary-rise method and cover the entire liquid range from the triple-point temperature to the critical temperature. Equations for calculating the surface tension of these n-alkanes as a function of temperature are presented.
63 citations
TL;DR: Palladium-containing titanium silicalite zeolites catalyse the hydroxylation of benzene and hexane by O2-H2 under mild conditions to give phenol and hexanols, respectively as discussed by the authors.
Abstract: Palladium-containing titanium silicalite zeolites catalyse the hydroxylation of benzene and hexane by O2–H2 under mild conditions to give phenol and hexanols, respectively.
61 citations
TL;DR: Direct esterifications using a nylon-immobilized lipase from Candida cylindracea using a packed-bed reactor was operated successfully for the continuous synthesis of esters, and the steady-state performance could be accurately predicted on the basis of batch reaction experiments.
49 citations
TL;DR: Excess volumes of mixing were measured at 20 o C for mixtures of three linear alkanes (hexane, heptane, and octane) and cyclohexane with five alkyl acetates (methyl, ethyl, propyl, butyl, and amyl acetates) and two ketones (acetone and 2-butanone).
Abstract: Excess volumes of mixing were measured at 20 o C for mixtures of three linear alkanes (hexane, heptane, and octane) and cyclohexane with five alkyl acetates (methyl, ethyl, propyl, butyl, and amyl acetates) and two ketones (acetone and 2-butanone). The whole composition range was studied for all 28 binary systems. For a given alkane, the excess volume decreases with the increasing size of the carbonyl compound. For a given carbonyl compound, the excess volume increases with the size of the alkane
48 citations
TL;DR: In this paper, a simplified mechanism consisting of 31 free radical reactions is used to calculate the overall rate of pyrolysis of n-hexane over the 77-500°C temperature range, at 210, 2000, 6000 and 15,000 bar.
48 citations
47 citations
35 citations
TL;DR: Of the organic solvents tested, highest biotransformation activities were observed with hexane and hexadecane, and lowest activities occurred with chloroform and toluene, while phospholipids were detected in reaction media from biocatalytic systems which exhibited cell damage in electron micrographs.
Abstract: Biotransformation of benzaldehyde and pyruvate to (R)-phenylacetyl carbinol bySaccharomyces cerevisiae was investigated in two-phase aqueous-organic reaction media. With hexane as organic solvent, maximum biotransformation activity was observed with a moisture content of 10%. Of the organic solvents tested, highest biotransformation activities were observed with hexane and hexadecane, and lowest activities occurred with chloroform and toluene. Biocatalyst samples from biphasic media containing hexane, decane and toluene manifested no apparent cell structural damage when examined using scanning electron microscopy. In contrast, cellular biocatalyst recovered from two-phase systems containing chloroform, butylacetate and ethylacetate exhibited damage in the form of cell puncturing after different incubation periods. Phospholipids were detected in reaction media from biocatalytic systems which exhibited cell damage in electron micrographs. Phospholipid release was much lower in the two-phase systems containing toluene or hexane or in 100% aqueous biocatalytic system.
32 citations
TL;DR: The transesterification rate in near-critical carbon dioxide proved to be much lower than in hexane at comparable conditions of temperature, water content, and substrate and enzyme concentration.
TL;DR: In this paper, the volatile components of violet leaves were extracted with 1,1,2-trichloro-1, 2,2, 2-trifluoroethane as well as hexane and analysed using GC, GC-MS and GC-FTIR.
TL;DR: In this article, the selectivity in the reaction is revealed in the presence of catalytic amounts of FeCI 3 : unusual selectivity has been observed in the reactions of cyclohexane, pentane, hexane, heptane and 3-methylhexane.
TL;DR: In this article, the catalytic activity of H3PW12O40 has been investigated in n-hexane cracking as a function of the reaction temperature, and it has been shown that both the polyacid and the anhydride phase formed by its dehydration are active catalysts for this reaction.
Abstract: The catalytic activity of H3PW12O40 has been investigated in n-hexane cracking as a function of the reaction temperature. It has been shown that both the polyacid and the anhydride phase formed by its dehydration are active catalysts for this reaction.
TL;DR: In this paper, a method for the determination of ionic alkyllead compounds in natural waters is described, which is based on the extraction of organolead compounds in the form of diethyldithiocarbamate complexes into hexane, their re-extraction with dilute nitric acid (pH 1.5), purification of the aqueous acidic solution from interfering co-extracted DICs, and determination of alkylead species by differential-pulse anodic stripping voltammetry.
TL;DR: In this paper, the rate constants for the spin exchange of various types of nitroxides were determined from the concentration dependence of the ESR line-broadening, and the exchange integral and steric factor were estimated from the pressure dependence of kex.
Abstract: The rate constants (kex) for the spin exchange of various types of nitroxides were determined from the concentration dependence of the ESR line-broadening. The exchange integral (J) and the steric factor (fs) for the spin exchange were estimated from the pressure dependence of kex. The estimated J-values are about 1011 s−1 and are almost independent of the radical species. For nitroxides having –OH or –NH2 in acetone and nitroxides having long-chain in acetone and toluene, the fs-values are about 0.3, while for other nitroxides in hexane and pentane, the fs-values are about 0.5. The results are discussed in terms of the solute–solvent interaction as well as the steric effect.
TL;DR: In this article, the effect of solvent on the stereochemistry of deprotonation of 4-heptanone in THF-hexane mixtures is plotted in the figure on the following page.
TL;DR: Excess molar enthalpies at the temperature 298.15 K were measured for (propan-1-ol + pentan-3-one + hexane) as well as for (Propan- 1-ol+ pentan 3-one), (proPan- 1 -ol+ hexane), and (pentan- 3 -one+hexane), using a Calvet microcalorimeter as discussed by the authors.
TL;DR: Trans-alkenyl iodides are treated with tert-butyllithium in hexane at room temperature to provide pure transalkenyllithiums in good yield as discussed by the authors.
TL;DR: In this paper, the results obtained in the simultaneous passive sampling of toluene, hexane, methyl ethyl ketone and ethyl acetate on activated charcoal are compared with results obtained when the compounds were tested individually.
TL;DR: In this paper, the relative reactivity to further oxidation is 4b > 4a and 5b > 5a, which suggests that the attractive 1,3-transannular interaction operative in 1,4-dithietane part of 4a, 5a and 6a decreases the reactivity of 4b and 5a.
Abstract: Oxidation of 2,2,3,3-tetramethyl-1,4-diphenyl-5,6-dithiabicyclo[2.1.1]hexane with m-chloroperbenzoic acid gives two isomeric endo- (4a) and exo-sulfoxides (4b), three S,S′-dioxides (endo, exo-5a, exo, exo-5b, and endo, endo-5c), and an S,S,S′-trioxide (6). The relative reactivity to further oxidation is 4b >> 4a and 5b > 5a, which suggests that the attractive 1,3-transannular interaction operative in 1,3-dithietane part of 4a and 5a decreases the reactivity of 4a and 5a. 4b isomerizes to 4a on standing over silica gel at room temperature and also 5b is converted to 5a on heating. Heating 6 in refluxing toluene yields 3,3,4,4-tetramethyl-1,2-diphenylcyclobutene, 2,5-dimethyl-3,4-diphenyl-2,4-hexadiene, and the isomeric trioxide.
TL;DR: The excess molar enthalpies of (N,N-dimethylformamide or N,Ndimethylacetamide + hexane, at 313.15 K) have been determined experimentally as a function of mole fraction.
Journal Article•
TL;DR: In this article, a working relationship between the solute binding energy and the solvent selectivity has been derived and this provides a good correlation for a variety of solvents interacting with the toluene/heptane system.
Abstract: Liquid phase solute-solvent interaction energies have been computed using a molecular graphics system coupled with mainframe Monte Carlo simulations. A working relationship between the solute binding energy and the solvent selectivity has been derived and this provides a good correlation for a variety of solvents interacting with the toluene/heptane system. Similarly, a relationship between the solute binding energy and the partition coefficient has been derived and this has been tested for various solvents interacting with the phenol/water system. The temperature dependence of the solvent selectivity has been examined for organo-sulphur solvents interacting with the benzene/hexane system
TL;DR: The capacity factors for multifunctional solutes with hydroxyl and carboxyl groups were measured on silica-immobilized bovine serum albumin (BSA) using various compositions of hydrogen chloride saturated diethyl ether, hexane, and neat diethodyl ether as discussed by the authors.
Abstract: The capacity factors, k', for multifunctional solutes with hydroxyl and carboxyl groups are measured on silica-immobilized bovine serum albumin (BSA) using various compositions of hydrogen chloride saturated diethyl ether, hexane, and neat diethyl ether. The values of k' are smaller at higher concentrations of free ether and larger as more of the ether is complexed with hydrogen chloride. Additionally, solute retention increases with increasing hydroxyl and carboxyl substituents in the molecule. The data indicate that solute retention is consistent with normal-phase behavior, which, to our knowledge, makes this work the first successful normal-phase application of silica-immobilized BSA to be reported.
TL;DR: In this paper, the authors measured data for the binary system hexane-aniline, along with published data for hexanebenzene and benzene-anILine, were correlated using Wilson, non-random two-liquid (NRTL), and UNIQUAC equations.
Abstract: Isobaric vapor-liquid equilibria at 101.325 kPa have been measured for the systems hexane-aniline and hexane-benzene-aniline. The measured data for the binary system hexane-aniline, along with published data for hexane-benzene and benzene-aniline, were correlated using Wilson, nonrandom two-liquid (NRTL), and UNIQUAC equations. The binary parameters, thus determined, were used to predict the ternary vapor-liquid equillibria (VLE) for the system hexane-benzene-aniline in good agreement with the measured data
Patent•
03 Apr 1992TL;DR: In this article, the oxazaborolidine-borane complexes are prepared by adding a C 5-8 alkane, typically hexane, to an aged solution of oxaborolidines and a source of borane such as boranes-dimethyl sulfide or gaseous diborane to crystallize the oxaborlinine complex.
Abstract: Oxazaborolidine-borane complexes are prepared by adding a C 5-8 alkane, typically hexane, to an aged solution of oxazaborolidine and a source of borane such as borane-dimethyl sulfide or gaseous diborane to crystallize the oxazaborolidine complex.
TL;DR: In this paper, isosteric heat of n-hexane on M x Na 56-2 x Y zeolites (M = Co, Ni, Zn, Cd) was determined from isotherms at two temperatures (288 and 298 K).
Patent•
27 May 1992
TL;DR: In this paper, a diphenyl ethane derivative was used as C-C labile polymerization initiator for polyethylenes at 260° to 400° C at a pressure of 60,000 to 350,000 kgfa.
Abstract: For the preparation of polyethylenes using a diphenyl ethane derivative as C-C labile polymerization initiator, 1 to 40 mole 3,4-dimethyl-3,4-diphenyl hexane, based on 1 million mole ethylene used, are polymerized at 260° to 400° C. at a pressure of 60,000 to 350,000 kgfa.