Calculation of the heats of solutions of alkylbenzenes in a nonpolar stationary phase

The heats of solution of 32 alkylbenzenes in nonpolar stationary phases (pentadecane, squalane, and Apiezon L) have been determined by gas-liquid chromatography. It is shown that the heats of solution of these substances may be calculated a priori as the sum of three quantities: a) the calculated dispersion force taking into account intramolecular screening; b) the energy of vacancy formation; and c) the interaction of the solvent molecules and the methyl groups of the solute. The presence of a double bond in the alkyl substituent increases the heat of solution of an alkylbenzene in the nonpolar stationary phase.