Thermodynamic study of 1,1,2,2-tetrachloroethane plus hydrocarbon mixtures I. Excess and solvation enthalpies.

The excess enthalpies, H-E, at 298.15 K for binary mixtures of 1, 1,2,2-tetrachloroethane (TCE) + an hydrocarbon (n-heptane, cyclohexane, benzene, toluene, ethyl-, n-propyl-, iso-propyl-, n-butyl-, sec-butyl-, and tert-butylbenzene) have been measured by flow microcalorimetry. All mixtures containing an aromatic hydrocarbon as second constituent exhibit negative H-E while mixtures with n-heptane or cyclohexane are endothermic. The H-E data have been analysed in terms of the DISQUAC model. Using a limited number of adjusted interchange energy parameters, C, taken as structure dependent, the model provides a fairly consistent description of H-E as a function of concentration. The enthalpies of solvation, Delta H degrees, of hydrocarbons in TCE, as obtained from heats of solution at infinite dilution and known vaporization enthalpies, have been described using an additive scheme of surface interactions. The effects of aromatic ring, chain lengthening, branching, and cyclization on both H-E and Delta H degrees have been discussed.