The Thermal Decomposition and Hydrolysis of Calcium Carbamoyl Phosphate

Article abstract of DOI:10.1246/bcsj.61.379

Calcium carbamoyl phosphate (1) was prepared by adding an aqueous calcium chloride to a reaction solution of KH2PO4 with KOCN. 1 was unstable at room temperature. 1 was dehydrated to make anhydrous salt and thermally decomposed to liberate ammonia, cyanic acid, and carbon dioxide, finally resulting in the formation of calcium pyrophosphate in air.The aaparent activation energies for the three endothermic peaks of the DTA curve were estimated to be 50.0, 83.9, and 148.3 kJ/mol respectively.The hydrolysis of 1 in an aqueous solution apparently obeyed the first-order kinetics.The activation parameters for the hydrolysis of 1 were evaluated by using the 31P NMR spectra of 1 with the lapse of the reaction time.The activation energy was 92.2 kJ/mol; the activation enthalpy, 89.7 kJ/mol, and the activation entropy, -6.3 e.u.