The thermal decomposition of sodium nitrate

The kinetics of the thermal decomposition of molten sodium nitrate have been studied as a function of temperature in the range 570–760°. The effect of replacing the air over the reactant by argon has been examined. From these measurements, it is concluded that atmospheric oxygen does not participate in the reaction and that, under isothermal conditions, the decomposition divides into two consecutive but overlapping parts, namely: (a) the initial decomposition of sodium nitrate to sodium nitrite, and (b) the subsequent break-down of sodium nitrite to form sodium oxide. A mechanism is postulated.