Infinite dilution liquid—gas partition coefficients of some volatile solutes with binary solvents exhibiting upper consolute temperatures
Abstract
Measurements of liquid—gas infinite dilution partition coefficients (KR) for furan, methyl formate and diethyl ether, as a function of volume fraction, in each of the mixtures (i) ethyl benzoate + propylene glycol and (ii) tributyl phosphate + ethylene glycol, are reported. Both solvent mixtures exhibit consolute behaviour, with upper consolute temperatures in the range 40–55 °C. It is shown that KR, for all six ternary systems, varies according to the equation KR=ΣK°Rϕ where K°R is the partition coefficient for a pure liquid and ϕ is its volume fraction in the mixture. The continuity of behaviour observed on passing through the sequence single-phase—two-phase—single-phase is shown to be consistent with behaviour previously reported upon for many single-phase g.l.c. solvent mixtures and with a solution model based on microscopic immiscibility of these solvents. The generality of the foregoing equation is thus considerably extended.