Review of experimental and recommended data for the excess molar volumes of 1-alkanol + n-alkane binary mixtures

Partition coefficients for a number of varied compounds were determined for the n-heptane-methanol and n-heptane-DMF partition systems and used to derive a general model for the distribution of neutral compounds in the biphasic systems. The partition coefficient, log Kp, was correlated through the solvation parameter model giving log Kp = -0.056 + 0.164E-0.620S-1.337A-0.957B + 0.507V for the n-heptane-methanol system with a multiple correlation coefficient of 0.986, standard error of the estimate 0.086, and Fischer statistic 413 for 65 compounds. For n-heptane-DMF, the model is log Kp = 0.065 + 0.030E-1.405S-2.039A-0.806B + 0.721V with a multiple correlation coefficient of 0.991, standard error of the estimate 0.080, and Fischer statistic 560 for 59 compounds. In the models the solute descriptors are excess molar refraction E, dipolarity/polarizability S, overall hydrogen bond acidity, and basicity A and B, respectively, and McGowan's characteristic volume V. Either model is expected to be able to estimate further values of the partition coefficient to about 0.08 log units and is applicable to a wide range of compounds. Applications include the choice of partitioning systems for sample clean-up, countercurrent chromatography, and estimation of solute descriptors for water insoluble or unstable compounds.

Distribution of neutral organic compounds between n-heptane and methanol or N,N-dimethylformamide.

Molecular transport of toluene, methanol, and cyclohexane and their mixtures in Chemraz 505 elastomer has been investigated using gravimetric techniques for short and long time exposure in these solvents. The sorption-desorption results have been used to calculate the diffusion coefficients by solving Fick's equation under appropriate boundary conditions. The dependence of sorption, desorption, diffusion, and permeation on temperature and composition changes was also studied. The results are discussed in terms of possible interactions between Chemraz 505 polymer and the solvent molecules.

Sorption equilibria and diffusion of toluene, methanol, and cyclohexane in/through elastomers

The dynamic shear viscosity of the binary liquid mixture methanol cyclohexane for different temperatures and concentrations is measured using digital viscometer with UL adapter. Shear viscosity anomaly is clearly observed near the critical temperature T c = 45.2 °C and the critical concentration X c = 30% by weight of methanol. The specific heat at constant pressure of the critical mixture methanol  cyclohexane was calculated using two scale factor universality. The dynamic scaling theory of Ferrell and Bhattacharjee is applied to the data of the ultrasonic absorption coefficients á c at different frequencies. The linear relation of versus was obtained. The adiabatic coupling constant g, isobaric thermal expansion coefficient á p and diffusion coefficient D were calculated. The experimental values of were plotted as a function of the reduced frequency ù* and it showed a good agreement with the theoretical scaling functionF(ù*) presented by Ferrell and Bhattacharjee.  2015 Trade Science Inc. INDIA

Adiabatic Coupling Constant g of the Binary Liquid Mixture Methanol – Cyclohexane

The volume change of mixing data for the methanol+hydrocarbon binary mixtures have been compiled and the best sets of data identified. The needs for new experimental data have been defined.

B. D. Smith

Papers

Evaluation of Binary Excess Volume Data for the Methanol+Hydrocarbon Systems