A thermochemical study on the coordination complex of cerium trichloroacetic acid with 8-hydroxyquinoline

The standard molar reaction enthalpies of two reactions, CeCl3·7H2O(s) + 3CCl3COOH(s)(or TCA) = Ce(TCA)3·3H2O(s) + 3HCl(g) + 4H2O(l) and Ce(TCA)3·3H2O(s) + 2C9H7NO(s) = Ce(TCA)(C9H6NO)2(s) + 2CCl3COOH(s) + 3H2O(l), were studied by classical solution calorimetry at 298.15 K. The molar dissolution enthalpies of the reactants and the products in certain solvent (the first reaction in 1 mol/l HCl, the second in a mixed solution consisting of absolute ethyl alcohol, dimethyl sulfoxide and 4 mol/l HCl) have been measured by using an isoperibolic calorimeter at 298.15 K. From the results and other auxiliary quantities, the standard molar formation enthalpies of [Ce(TCA)3·3H2O, s, 298.15 K] and [Ce(TCA)(C9H6NO)2, s, 298.15 K] were determined to be ΔfHmθ [Ce(TCA)3·3H2O, s, 298.15 K] = −3059.9 kJ/mol and ΔfHmθ [Ce(TCA)(C9H6NO)2, s, 298.15 K] = −1368.9 kJ/mol.