GB958778A - Improvements in and relating to the production of hydrazine - Google Patents

Abstract

N2H4 is produced in a system containing a gas and liquid by subjecting an ammoniacontaining gas to an intermittent, i.e. in pulses, electric discharge in the presence of anhydrous liquid NH3, H2O or aq. NH3. The liquid may be injected into the discharge as a pool, mist, falling film, jets or droplets large enough to fall under gravity, e.g. 0.2-2 mm. diameter. The gas may be NH3, N2 or another inert gas at a pressure up to 0.5 atm. and preferably below 1000 DEG C., e.g. by cooling surfaces in the discharge chamber. The discharge may be a spark, arc, glow or corona with A.C., R.F., or D.C. which may be combined with a superimposed field and may be electrodeless, e.g. separated by a dielectric, e.g. glass or quartz, or using corrosion-free electrodes of or plated with a metal or alloy, e.g. Pt, W, Ni, stainless steel, Ni- or Cr-Cu alloys. The liquid may contact the reactant present either in the positive column or cathode fall region of the discharge and may cover at least the cathode. The pulse length may be up to 10-2 sec., the current density at least 10-3 amp./cm.2 and the product of these two may be from 10-4 to 10-7. The field strength/unit pressure may be up to 100v./cm./mm. Hg. A catalyst, e.g. for recombination of H atoms may be present. In an example, a heat resistant glass cylinder surrounded by a cooling jacket and fitted with a hollow Ni cylinder as cathode and Pt wire as anode was fed with 35% aq. NH3. The cylinder was cooled to - 78 DEG C. by methanol/CO2 and evacuated to 2.5-3.0 mm. Hg. A D.C. glow discharge was struck and then pulsated, and N2H4 was produced. Specifications 735,655, 948,772, 958,776 and 958,777 are referred to.