Catalytic decomposition of sodium chlorate
1970; Elsevier BV; Volume: 19; Issue: 2 Linguagem: Inglês
10.1016/0021-9517(70)90279-4
ISSN1090-2694
Autores Tópico(s)Thermal and Kinetic Analysis
ResumoThermogravimetry (TG) and differential scanning calorimetry (DSC) were used to study the catalytic decomposition kinetics of sodium chlorate. Cobalt oxide (Co3O4) preparations of known crystal structure, particle size, surface area, electrical conductivity, and chemical composition were used for catalysts. Co3O4 powder prepared from cobalt carbonate was found to be a sufficiently active catalyst to initiate decomposition of solid NaClO3 as well as sodium perchlorate. As much as 60% of the total amount of NaClO3 decomposed was found to occur in the solid state with 6.84% Co3O4 using TG at various heating rates. A change in phase from solid to liquid NaClO3 was accompanied by an increase in the catalytic decomposition rate. The Freeman-Rudloff mechanism for the decomposition of chlorates is used to explain the high activity of the p-type semiconductor, Co3O4. The apparent activation energy for the catalytic decomposition of solid NaClO3 increased from 28.5 to 47.6 kcal/mole in the range from 5 to 50% decomposition with 6.84% catalyst. Gamma preirradiation of the catalysts in air decreased their activity. There was no evidence of an induction period in the catalytic decomposition of solid NaClO3 thus showing rapid nucleation of decomposition. The average measured heat of fusion of NaClO3 using DSC was 5330 cal/mole with an average deviation of ±144 cal/mole.
Referência(s)