Electrical Synthesis of Nitric Oxide

Abstract

THE synthesis of nitric oxide from its elements by means of an electric discharge has long been recognised as highly anomalous, since the data upon the reaction N₂ + O₂ 2NO – 43.2 kcal. indicate that if the discharge be regarded simply as a zone of exceedingly high temperature, the maximum yield of product should be obtained by the passage of an equimolecular mixture, followed by the most rapid cooling to c. 1,000° C., and independently of the pressure of the gas. In practice, however, the best results are obtained with slow circulation at c. 100 mm., a mixture of one part of nitrogen and four parts of oxygen being nearly as effective as the other. It has therefore been supposed that, apart from possible errors in the calculations due to extended extrapolation, the reaction is primarily electrical and incapable of simple thermodynamic interpretation, although conditions of experiment may in some cases permit of the superposition of a thermal process so strong that predictions are fulfilled.