氨基苯甲酸异构体在水—乙醇混合溶剂中的离解焓和熵

Dissociation Enthalpies and Entropies of Amino Benzoic Acids in Water - ethanol Mixtures

利用流动混合微量热法测定298.15 K时单取代氨基苯甲酸邻,间,对三个异构体在水-乙醇混合溶剂中两个官能团分步离解的离解焓,结合相应的Gibbs自由能数据计算离解熵,从溶剂效应和取代基位置效应探讨其离解热力学行为.

The dissociation enthalpies of o -, m -, p - amino benzoic acid in water - ethanol mixtures ranging from pure water up to 0.477 molar fraction of ethanol have been determined at 298. 15 K by the method of mixing - now microcalorimetry. Combined with the available values of Gibbs free energy reported in the literature, the corresponding values of dissociation entropy were calculated. The enthalpic and entropic effects arising from solvent and substituent are discussed in terms of solute - solvent interaction and tautomeric equilibrium.