Hydrazine Synthesis in the Silent Electrical Discharge

Abstract

THE synthesis of hydrazine from ammonia in the silent discharge was first reported by Besson¹. Subsequent investigations by other workers on flowing systems^2,3 only led to both low conversion and very low hydrazine yields being obtained. The yields are normally expressed as grams of hydrazine per kilowatt hour of energy dissipated in the actual discharge. More recent work claims substantially increased yields by withdrawal from the discharge of the desired product in an absorbent⁴. A reasonable working explanation for the increase in yield reported in this case could well be as follows. The reactions in the discharge are undoubtedly of a very complex nature probably consisting of a series of competing formation and degradation reactions for any particular species in the discharge. The use of an absorbent is equivalent to reducing the residence time of the chemical species in the discharge, that is, it reduces the possibility of its decomposition by either further electron bombardment or other collision phenomena. Ideally, the absorbent would be selective only for the product and allow the activation reactions to take place virtually unhindered by its presence. Furthermore, if the effect of the absorbent is assumed to be entirely physical in nature, it follows that any method of reducing the residence time of the product in the discharge would be expected to enhance yields. Other possible methods of achieving this same end are increased flow rate, pulsing of the discharge or removal of product by condensation, adsorption or chemical combination.