Thermal degradation kinetics of Co(II), Ni(II), and Zn(II) hydrazinesulfinates in air, oxygen and nitrogen atmospheres

Abstract

Cobalt, nickel and zinc hydrazinesulfinate complexes of the molecular formula M(N 2H 3SOO) 2 where MCo, Ni and Zn, respectively, have been prepared and characterized by analytical and spectral techniques. The thermal decomposition of these complexes have been studied in three different atmospheres, viz. static air, oxygen and nitrogen. In static air, cobalt and zinc complexes give respective metal sulfites while the nickel complex yield nickel sulfate. In oxygen atmosphere, cobalt complex gives a mixture of oxide and sulfate while the nickel and zinc complexes yield the respective metal oxide. In the nitrogen atmosphere, the complexes decompose to yield a mixture of metal sulfide and metal sulfite in the case of cobalt and nickel while zinc complex gives ZnO. The above complexes have also been subjected to sudden heating at high temperatures ca. 500 °C, i.e. combustion, which resulted in the formation of metal oxide in the case of cobalt while the nickel complex gives nickel sulfide as the final product. However, the zinc complex gives mixture of zinc oxide and zinc sulfate. The kinetic parameters were evaluated for these complexes using Coats–Redfern equation. The parameters have been studied on the basis of TG-data and in most of the cases, the decomposition is found to follow first order kinetics.