Activity coefficients of benzene in solution of n-alkanes and the second virial coefficients of benzene + nitrogen mixtures. Gas-chromatographic investigation

Abstract

The activity coefficients of benzene in a series of n-alkanes and the mixed second virial coefficients of benzene + carrier gas have been determined by gas chromatography. Nitrogen has been used as carrier gas in most cases. The experimental procedure and method of data analysis have been discussed in previous papers. The mixed second virial coefficients have been compared with values predicted by the principle of corresponding states. The activity coefficients of several of the benzene + n-alkane mixtures were studied over a temperature range and the excess partial molar enthalpies at infinite dilution have been calculated for these systems. These enthalpies have been compared with data obtained calorimetrically by other workers on the lower n-alkane + benzene mixtures. The activity coefficients, extrapolated to the same temperature, have been discussed in terms of the quasi-lattice theory. Both “segment” and “contact point” treatments, previously used for n-alkane mixtures, have been extended to binary mixtures of n-alkanes with substances having one type of contact point or segment. The experimental results are adequately explained in terms of constant “benzene-end” group, “benzene middle group” and “end-middle” group interchange energies.