The urea decomposition in the process of the heterogeneous catalytic denitration of nitric acid solutions: Part II. Reaction’s products and stoichiometry

The reaction products and the stoichiometry of the urea catalytic decomposition in the system HNO3–HCOOH–Pt/SiO2 were studied with an application of the IR spectroscopy, the mass spectroscopy methods and chemical analysis. It was found that in the presence of 0.1 g ml−1 1% Pt/SiO2, the 0.1–0.4 M (NH2)2CO decomposes at 50–90 °C in the solutions of 2.5–6.4 M HNO3 containing 0.25–1.5 M HCOOH according to a stoichiometric equation: 3(NH2)2CO+3HCOOH+5HNO3→Pt2N2+N2O+2NH4NO3+NH2CHO+5CO2+6H2O. e reaction products—the ammonium nitrate and the formamide—undergo further a gradual degradation under the conditions of a catalytic denitration reaction that starts when the urea decomposition is completed.