Thermochemical Study on Coordination Complex of Neodymium Trichloroacetic Acid with 8-Hydroxyquinoli

Two coordinate reactions, NdCl3*6H2O(s) +3CCl3COOH(s)( or TCA) =Nd(TCA)3*3H2O(s) +3HCl(g) +3H2O(l) and Nd(TCA)3*3H2O(s) +2C9H7NO(s)= Nd(TCA)(C9H6NO)2 (s) +2CCl3COOH(s) +3H2O(l), were studied by the classical solution calorimetry at 298.15K. The molar dissolution enthalpies of the reactants and the products in certain solvent (the first reaction in 1 mol*L-1 HCl, the second in a mixed solution consisting of absolute ethyl alcohol, dimethyl sulfoxide and 4 mol*L-1 HCl ) were measured by using an isoperibol calorimeter at 298.15K . From the results and other auxiliary quantities, the standard molar formation enthalpies of [Nd(TCA)3*3H2O,s,298.15K] and [Nd(TCA) (C9H6NO)2 ,s, 298.15K] are determined as ΔfHm°[Nd(TCA)3*3H2O,s,298.15K]= -3053.3 kJ*mol-1 and ΔfHm°[Nd(TCA) (C9H6NO)2 ,s, 298.15K] = -1355.6 kJ*mol-1.