Thermochemistry of the Dissolution of Tetra-4-(4'-carboxyphenyoxy)- and Tetra-4-(4'-carboxyphenylthio)phthalocyanines of Copper in Aqueous Solutions of KOH at 298.15 K

Abstract

The authors obtain complexes CuPc(4-S-C6H4-COOH)4 and CuPc(4-O-C6H4-COOH)4 that are insoluble in water. The standard enthalpies of formation of these compounds are calculated using additive groups based on group systematics with Benson-type classification of fragments, allowing for the influence of the atoms’ primary environment. Thermal effects of the dissolution of crystalline phthalocyanines in aqueous solutions of various KOH concentrations at a temperature of 298.15 K were determined via direct calorimetry. Thermal effects of the stepwise dissociation of CuPc(4-S-C6H4-COOH)4, CuPc(4-O-C6H4-COOH)4 are calculated using the HEAT computer program. Standard enthalpies of formation are calculated for products of the dissociation of CuPc(4-S-C6H4-COOH)4 and CuPc(4-O-C6H4-COOH)4 in an aqueous solution.