Heterogeneous Decomposition of Hydrazine: Part 1.—On a Supported Rhodium Catalyst

Abstract

A study has been made of the kinetics of the decomposition of aqueous hydrazine solutions on a supported rhodium catalyst. The decomposition may be represented by the reaction : 2N2H4->N2 + H2 + 2NH3 and it has been shown, using N15 as a tracer, that the nitrogen molecule is formed from the two nitrogen atoms of one hydrazine molecule without N—N bond fission. The kinetics exhibit a change from one-half order at low concentrations of hydrazine to zero order at high concentrations of hydrazine. The activation energy of the reaction was calculated to be 41.28 ±0.33 kJ mol'1 and the prc-exponential factor 3.45 x 102 mole g-1 s'1. A reaction mechanism is postulated which involves the dissociative chemisorption of hydrazine followed by reaction between adsorbed NH radicals and molecularly adsorbed hydrazine molecules.