Properties of polar gases and their association in the liquid phase

Abstract

Using the second virial coefficients of polar gases the liquid-phase dimerization constants are calculated independently of any assumptions about the formation of higher multimers. The higher multimerization constants are determined by assuming that the two-constant athermal Mecke—Kempter (MK2) and Kretschmer—Wiebe models hold for a polar liquid. In agreement with the experimental evidence, the one- and two-constant models predict that plots of the mean mole fraction of free OH groups in n-alkanol + alkane systems vs. the molar concentration of a solute form corresponding states isotherms. The mean mole fractions of free OH groups in neat alcohols and in alkane solutions predicted using the MK2 model agree well with the experimental values. The MK2 model predicts also the partial molar excess enthalpies of alcohols and amines at infinite dilution with satisfactory accuracy.