Diffusion of Salts across a Butanol-Water Interface

Abstract

Diffusion of the chloride salts of Li, Na, K, Rb, and Cs from water into 1-butanol and from 1-butanol into water was examined at temperatures from 13-40 degrees C. Distribution coefficients, interfacial transfer coefficients, Arrhenius activation energy, free energy of activation, enthalpy, and entropy of activation were determined for the diffusion of these salts across the alcohol-water interface. The results indicate that the entropy decrease made the major contribution to the change in the free energy of activation.

Intestinal mucous membranes: The role of interfacial phenomena

“…The value of the kow was 0.00417 cm sec -1. This is greater than the interfacial transfer coefficient for NaOH transfer from butanol to water (0.0012 cm sec -1) [20]. This suggests that some of the energy stored in the interfacial film about the micelle was available to facilitate the transfer of the Na across the hexane-water interface.…”

“…The apparatus is shown in Fig. 2, and the experimental techniques and the theoretical considerations have been reported previously [20]. The salt is added to the water phase, and its appearance in the butanol phase is followed by taking samples from the butanol phase at set time intervals.…”

Thermodynamics and membrane processes

“…This free-energy term is composed of both enthalpic, AH°O W , entropic, AS°0 W , and molar volume change A V°o w , terms. Many partitioning phenomena have been shown to be of substantially entropic origin (Kauzmann, 1959;Ting, Bertrand & Sears, 1966;Rosano, Duby & Schulman, 1961). Diamond and Katz (Katz & Diamond, 1974a, b;Diamond & Katz, 1974) in a series of papers have examined rather closely the thermodynamic interpretation of partition coefficients by comparing dimyristoyl lecithin liposomes with a variety of bulk solvents.…”

Mass transfer through a liquid/liquid interface, a useful model for membrane permeation?

“…By employing inference obtained through variation of the temperature, some investigators even went so far as to separate this free energy into an enthalpic and an entropic contribution (5,6).…”