A thermochemical study of the coordination reactions of La(III) with alanine and glycine

摘要

The solid-state coordination reactions of lanthanum chloride with alanine and glycine, and lanthanum nitrate with alanine have been studied by classical solution calorimetry. The molar dissolution enthalpies of the reactants and the products in 2 mol L~(-1) HCl solvent of these three solid-solid coordination reactions have been measured using an isoperibol calorimeter. From the results and other auxiliary quantities, the standard molar formation enthalpies have been determined to be △_fH_m~θ[La(Ala)_3Cl_3·3H_2O(s), 298.2 K] = -3716.3 kJ mol~(-1), △_fH_m~θ[La(Gly)_3Cl_3·5H_2O(s), 298.2 K] = -4223.0 kJ mol~(-1) and △_fH_m~θ[La(Ala)_4(NO_3)_3·H_2O(s), 298.2 K] = -3867.57 kJ mol~(-1), respectively.