Showing papers on "Hexane published in 1972"
TL;DR: In this paper, a review of diffusivities in carbon tetrachloride and hexane at 25°C indicated that the diffusivity of essentially linear molecules were, in general, about 30 per cent higher than for substances composed of essentially spherical molecules having the same molar volume at the normal boiling point.
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TL;DR: In this article, the critical temperature T c and critical pressure p c were measured at five compositions for each of five binary mixtures formed by propane with perfluoropropane, perfluoro- n -hexane, hexafluoroacetone,hexafluorobenzene, and trifluoroacetonitrile.
27 citations
TL;DR: In this paper, precise concentrations of n-butyllithium in solutions of hexane in various ethers were determined by direct titration at −78° with sec-butanol.
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TL;DR: In this article, the enthalpies of mixing at 25 °C for binary and ternary mixtures composed of 1-pentanol, n-hexane, and cyclohexane were fitted to smooth curves using a power-series.
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TL;DR: The hydration constants for the TOPO HOH associate have been determined in the solvents n -hexane, cyclo hexane, m -xylene, carbon tetrachloride, benzene, toluene, carbon disulphide, chloro benzene and 1,2-dichloro ethane as discussed by the authors.
TL;DR: In this paper, experiments to confirm Kubo's conclusion on the complex formation of 1,2-dichloroethane with benzene were carried out following his procedure.
Abstract: Experiments to confirm Kubo’s conclusion on the complex formation of 1,2-dichloroethane with benzene were carried out following his procedure. Dielectric measurements were carried out with inert solvents hexane and cyclohexane. The interactions between 1,2-dichloroethane and each of the compounds toluene and p-xylene were also studied with inert solvents hexane, cyclohexane, and carbon tetrachloride. The results are discussed in relation to complex formation.
TL;DR: In this article, specific interaction of aqueous solutions of cyclodextrin derivatives has been investigated with respect to the isomers hexane and 2,3-dimethylbutane.
Abstract: Specific interaction of aqueous solutions of cyclodextrin derivatives has been investigated with respect to the isomers hexane and 2,3-dimethylbutane.
Saturated vapour of hexane or 2,3-dimethylbutane is equilibrated with aqueous solutions of different concentrations of cyclodextrin derivatives at 1, 10, 20, 30 and 40°. The solubilities of the hydrocarbons in these solutions and in water are measured gaschromatographically. It appears that linear interaction isotherms are formed, from which the degree of occupation of the cyclodextrin voids can be calculated, assuming for the present a 1 : 1 composition of the inclusion complex.
The complex association constant has been calculated for the equilibrium: saturated vapour + cyclodextrin derivative ⇆ inclusion complex.
Plots of the natural logarithms of the association constants vs 1/T show linear relationships. The standard molar values of the free enthalpy, enthalpy and entropy pertaining to the above-mentioned equilibrium have been calculated.
TL;DR: In this paper, the authors measured the rate constants for the gas phase isomerization of bicyclo[2.2.0] and 1,4-dichlorobicyclo[1.2] hexane and showed that the radical stabilization energy of an α-bromine atom is 1.0 ± 1.8 kcal/mole.
Abstract: The kinetics of the gas phase isomerization of 1-chloro-4-bromobicyclo[2.2.0]hexane to 2-chloro-5-bromohexa-1,5-diene have been measured in a static system over the temperature range of 135–215°C, with a variation in the total pressure from 0.6 to 400 torr. For these conditions the rate constants are well represented by the Arrhenius equation:
where θ = 2.303RT kcal/mole. Transition state estimates for the biradical mechanism for the isomerization of bicyclo[2.2.0]hexanes are shown to be in good agreement with these Arrhenius parameters. By comparison of the activation energy with that for the isomerization of bicyclo[2.2.0]hexane and 1,4-dichlorobicyclo[2.2.0]hexane, the radical stabilization energy of an α-bromine atom is shown to be 1.0 ± 1.8 kcal/mole. Rates are also reported in the liquid phase at temperatures of 155°C and 175°C with diphenyl ether, nitrobenzene, and dimethylsulfoxide as solvents. The observed rate constants are all faster (by a factor of 1.1–1.7) than those measured in the gas phase and display no correlation between rate and solvent polarity.
TL;DR: In this paper, Catalytic cracking of n-hexane over NaX and various samples of the nickel-exchanged zeolite have been studied, showing that the initial chemisorption of hexane appears to occur on a relatively small number of preferentially exchanged nickel ions, which can each lead to the removal of many hexane molecules from the gas phase before losing their activity.
TL;DR: In this article, the authors studied the thermal isomerization of 1-chloro-4-methoxymethyl-log(kb/s-1) = (14.1 ± 0.2)-(36.2 ± 1.5)/θ where θ = 2.303RT kcal/mol and the subscripts g, a, and b refer to the gas phase.
Abstract: The kinetics of the thermal isomerization of 1-chloro-4-methoxymethyl- log(kb/s-1) = (14.1 ± 0.2)-(36.2 ± 0.5)/θwhere θ = 2.303RT kcal/mol and the subscripts g, a, and b refer to the gas phase, nitrobenzene-d5 as solvent, and diphenyl ether as solvent respectively. The Arrhenius parameters are discussed in terms of transition state estimates for a biradical mechanism. With reference to the isomerization of bicyclo[2,2,0]hexane and 1,4 dichlorobicyclo[2,2,O]hexane, the α-methoxymethyl group is shown to destabilize the biradical by 6.1 ± 2.4 kcal/mol by comparison with an α-propyl group. This radical destabilization by the β-ether oxygen atom is explained in terms of the inductive effect of the β-electronegative atom.
TL;DR: In this article, the effect of pressure on the various contributions to the total ultrasonic absorption in toluene and hexane in the pressure range (1⧀v10000) kg/cm2 under some specific assumpons has also been exploited.
Abstract: Hirai and Eyring’s notion of holes in a liquid lattice has been employed to demonstrate the effect of pressure on the various contributions to the total ultrasonic absorption in toluene and hexane in the pressure range (1⧀v10000) kg/cm2 Under some specific assumpons, the pressure dependence of the thermal relaxation time for these Kneser-type liquids has also been exploited
TL;DR: Methods are reported for the manual spectrophotometric or fluorometric estimation of tocopherol in human cerebrospinal fluid and color developed by adding bathophenanthroline, ferric chloride, and orthophosphoric acid.
Abstract: Methods are reported for the manual spectrophotometric or fluorometric estimation of tocopherol in human cerebrospinal fluid. The fluid is centrifuged, an equal volume of ethanol is added, and the tocopherol is extracted with hexane, which is then used for the direct estimation by fluorometry. The fluorescence of tocopherol is significantly affected by the proportion of ethanol in the hexane solvent. The standards used for comparison should therefore be dissolved in hexane that had been previously equilibrated with twice its volume of ethanol:water (1:1 by vol). For spectrophotometry, the original hexane extract is dried at 40°C under reduced pressure, the residue dissolved in hexane, and color developed by adding bathophenanthroline, ferric chloride, and orthophosphoric acid. The color is measured at 536 nm. Concentrations of tocopherol in the spinal fluid samples analyzed so far ranged from 40 to 210 µg/ liter.
TL;DR: In this article, a cyclohexa-1,4-diene formed from the thermal isomerization of tricyclohexane undergoes a hot molecule decomposition to benzene and hydrogen.
Abstract: At low pressures cyclohexa-1,4-diene formed from the thermal isomerization of tricyclohexane undergoes a hot molecule decomposition to benzene and hydrogen; theoretical calculations (RRKM) give a good description of the experimental results.
TL;DR: In this article, the potassium naphthalenide system has been studied in various mixtures of 1, 2-dimethoxyethane and hydrocarbon solvent (benzene, cyclohexane and n -hexane).