OXYGEN EVOLUTION FROM PRODUCTS CONDENSED AT LIQUID-AIR TEMPERATURE IN DISSOCIATED WATER-VAPOR SYSTEM

Kinetics of the oxygen evolution from products (≈0.02 g) condensed at liquid-air temperature from water vapor dissociated in a microwave discharge at low flow rates (1.875 mmoles H2O/h) and low pressures (0.12 mm Hg) were studied at -80°C by the method of isothermal decomposition. Although one-third of the oxygen was evolved in about 1 h, the oxygen evolution was completed over a period of several days only, suggesting the occurrence of an initial fast reaction followed by a much slower reaction. The shape of the kinetic curves varied somewhat for products from different experiments under apparently the same conditions, and the data did not follow first- or second-order kinetics. These results are compared to data earlier obtained using both uniform heating and isothermal decomposition methods, and it is shown that H2O2 decomposition cannot adequately explain the oxygen evolution. On the other hand, the slower reaction can be explained by decomposition of the postulated hydrogen Superoxides. Copyright ©1969 by the Americn Institute of Physics.