GB948772A - Improvements in and relating to the production of hydrosine - Google Patents

Abstract

N2H4 is produced by subjecting gaseous NH3 to an electric discharge in the presence of O2 in a minor proportion by moles relative to the NH3 taking part in the reaction and optionally a liquid. The electric discharge may be spark, arc, glow, or corona used with A.C. or D.C., or A.C. with a field of constant alternating polarity, and the electrical energy may be in pulses and the A.C. may be applied capacitively or an electrodeless discharge may be used. The liquid is water or anhydrous or aqueous NH3 and may be injected into the discharge as one or more jets or droplets, e.g. 0.2-2 mm. diameter, large enough to fall under gravity, or may be present as a pool, mist or falling film on the electrode or reaction chamber walls. The O2 may be fed to the centre of the discharge through a nozzle in the electrode, radially toward the axis of discharge from the periphery, through an annular opening outside one or more electrode or towards the cathode fall region of the discharge, and may be fed beneath the surface of a liquid. Rate of feed of the O2 may be 40/400 moles/Faraday and the O2 may be mixed with NH3 or inert gases, e.g. A or N2, as air. The gas pressure may be below 2 atmospheres, e.g. 5-100 mm. Hg, and the temperature below 1000 DEG C. The electrodes may be of or plated with corrosion-free metal or alloys, e.g. Pt, W, Ni, stainless steel or Ni or Cr plated Cu. A catalyst, e.g. for recombining H atoms or reacting H2 and O2 may be present in the reaction. In an example, a heat resistant vessel fitted with 2 Pt electrodes was cooled to - 75 to - 78 DEG C. and filled with NH3 at 50 mm. Hg. Liquid anhydrous NH3 containing NH4 NO3 (for electrical conductivity) which may be in equilibrium with the gaseous NH3, immersed the plate cathode electrode which was vertically beneath the anode, in the form of a tube, which was fed with a mixture of O2 (0.012 mole/hour) and NH3 (0.04 mole/hour). A D.C. discharge was struck between the electrodes and the liquid was then withdrawn for the N2H4. Aq. NH3 is used to produce N2H4 hydrate. Specification 735,655 is referred to.