The effect of zinc oxide was studied on the vapor-phase decomposition of perchloric acid. The interaction between the catalyst and the substrate was investigated by infrared spectroscopy, electric conductivity, thermal and chemical analysis. The interaction was most pronounced at 250° when a great amount of zinc perchlorate was formed. Zinc oxide catalyzed the decomposition of perchloric acid above 310°. The reaction followed first-order kinetics. The value of the activation energy was 45 kcal/mol. Experiments were performed with magnesium and cadmium oxides too; however, both oxides were found to be inactive substances. Taking into account the stability of perchlorate salts and the activity order of the oxides, the conclusion was drawn that the formation and decomposition of surface perchlorate may play an important role in the catalytic decomposition of perchloric acid. Measurements were also carried out on the catalysis of the gas-phase decomposition of ammonium perchlorate; in this process zinc oxide was found to be an outstanding catalyst.
ASJC Scopus subject areas
- Physical and Theoretical Chemistry