On the use of dilution calorimetry in the study of hydrogen-bonding self-association reactions: benzoic acid in benzene

Abstract

A calorimetric dilution method was applied to the system benzoic acid in benzene at 25 °C. Two different calorimeters, a batch calorimeter (at Guelph) and a flow microcalorimeter (at Sherbrooke), were used in this study. Our results were inconsistent with an ideal monomerdimer model, which had been used in previous calorimetrie studies on this and other similar systems. Our results were consistent with an ideal monomer–dimer–trimer model, for which we obtained: K 2 = 625 ± 100 L/mol, [Formula: see text] for the dimerization and trimerization constants respectively, and ΔH 2 0 = −8.52 ± 0.50 kcal/mol, ΔH 3 0 = −13.48 ± 2 kcal/mol for the molar enthalpies of dimerization and trimerization, respectively.