Kinetic and Mechanistic Studies on the Decomposition of Nickel Salicylate

Nickel salicylate has been prepared, characterized and its mode of thermal decomposition investigated by thermogravimetric analysis, differential thermal analysis and analysis of the intermediates. It was found from these studies that nickel salicylate decomposes by a three-step mechanism. The first step, in the temperature range 25-105°C. involves the loss of the water of crystallization, yielding the anhydrous material. The second step. in the temperature range 105-285°C is the loss of one of the salicylate ions, and the third and final step, in the temperature range 285-430°C. is the oxidation of this intermediate to the oxide. By following the rate of $CO_2$, evolution from the intermediates obtained after steps I and II of decomposition by mass spectral technique, the activation energies have been obtained. The activation energies for steps II and III were found to be 12 and 44 kcal $mole^{-1}$. respectively. While the former has been assigned to some physical process such as diffusion, the latter has been attributed to the process of Ni-0 bond breakage