GB778451A - Improvements in or relating to the manufacture of hydrazine - Google Patents

Abstract

In the production hydrazine by a two stage reaction of sodium hypochlorite with ammonia as aqueous medium, sufficient ammonia is initially employed to produce chloramine in an intermediate reaction zone, e.g. at a temperature less than 15 DEG C., the amount of ammonia emplayed being less than one-tenth of the total ammonia employed in the reaction, whereafter the intermediate reaction product is passed without back mixing to the final reaction zone, in the presence of a negative catalyst, after admixture with gaseous ammonia at elevated pressure to provide a molar ratio of ammonia to chloramine of 15-45 : 1 and to heat the reaction mixture to 120-150 DEG C., the reaction period in the final reaction zone being limited to 3-30 sec. The solution may be heated, if necessary, by means of a heat exchanger after introduction of the gaseous ammonia. A pressure of 200-400 p.s.i.g., preferably 300 p.s.i.g., may be maintained in the final reaction zone which may be in the form of a tubular reactor having a length to diameter ratio of 15-18 to 1. After completion of the reaction ammonia is flashed off and returned to the process. Hydrazine is recovered from the liquid remaining in known manner. As catalyst 0.066-0.33 gm. of fish glue or gelatin per litre may be employed. Specifications 22957/07 and 139/08 [both in Class I] are referred to.