The effect of catalysts on the thermal decomposition of sodium superoxide

Abstract

Simultaneous differential thermal, thermogravimetric and differential thermogravimetric analysis have been made on samples of sodium superoxide and sodium superoxide containing l% (w/w) copper(I) oxide. Decomposition of the superoxide involving oxygen production (weight loss) does not occur at a meaningful rate until temperatures approach 250°. The effects of 12 metallic oxide catalysts and one metalloorganic catalyst on the decomposition of sodium superoxide have been studied by differentialthermal analysis. Six metallic oxides had no effect while 3 oxides, (palladium oxide, titanium oxide and cadmium oxide) caused small but distinct changes in the DTA plots. A polymeric phthalocyanine, and the oxides of vanadium(III), vanadium(V) and manganese (IV) apparently reacted with the superoxide above 250°. Pretreatment of the superoxide by brief exposure to 100% humidity resulted in the formation of peroxyhydrates of sodium peroxide which upon dissociation produced water vapor in turn causing the release of oxygen from the superoxide and peroxide at lower temperatures than those experienced with untreated superoxide samples.