The thermal decomposition of nickel terephthalate and nickel salts of other carboxylic acids

Abstract

The thermal decomposition of solid nickel terephthalate in the range 365–440° yielded carbon dioxide, carbon monoxide, benzene, biphenyl, nickel metal, and other products. Kinetic measurements showed that the carbon dioxide formation reaction obeyed the Avrami equation though the reaction rate and the Avrami exponent varied for different salt preparations; samples having small crystallite size obeyed the first-order equation. The activation energy for the decomposition of all samples was 54·0 ± 2·0 kcal. mole^–1. The Arrhenius parameters measured have been compared with similar data for those nickel salts of other carboxylic acids for which measurements were available. It is concluded, from these comparisons, that the reaction of nickel terephthalate involved rupture of two metal–carboxyl group linkages, within the amorphous reactant matrix, to form a nucleus of nickel metal, the growth of which was largely confined to decomposition of the crystallite on which nucleation occurred.