Improvements in the production of nitriles

摘要

A catalyst for use in converting N-formyl amines to the corresponding nitriles is prepared by treating a silica gel containing 90% of pores with a radius ranging between 10 and 200 , the mean pore radius being 48,9 , and having an internal surface of 314 square metres per gram and an exchange acidity of between pH 5 and 6,6, with an alcoholic solution of titanium tetrachloride, allowing to stand in air for 15 minutes, treating with water and finally heating in a current of ammonia for 10 hours at 300 DEG C. Specification 263,198 is referred to.ALSO:Nitriles are prepared by reacting an N-formylated primary amino compound at 400 DEG to 600 DEG C in the gas phase on a catalyst of silicic acid gel or a silicate, said materials having more than 50% of pores with a radius ranging from 10 to 200 , a mean pore radius of 20 to 100 and an internal surface of less than 550 square metres per gram. The catalyst preferably additionally contains an oxide of a metal of one of the Group III to VI of the Periodic System and may be regenerated by heating to between 400 and 750 DEG C. in a current of oxygen or oxygen-containing gas, followed, if desired, by treatment with a dilute acid. The N-formylated amine reactant may be prepared from the appropriate amine and formic acid or an ester thereof in a zone of elevated temperature preceding the catalyst zone. Starting materials may be aliphatic, aromatic or heterocyclic in nature and may be further substituted by methoxy, chloro and nitrile substituents, as well as containing more than one formylamino group. The examples describe the preparation of benzonitrile, ortho-and para-tolunitriles, ortho-chlorobenzonitrile (saponified to ortho-chlorobenzoic acid), alpha - naphthonitrile, hexahydrobenzonitrile, benzyl cyanide, acetonitrile, suberic acid dinitrile, amino-oenanthic nitrile, sebacic acid dinitrile and omega-amino-pelargonic nitrile. Specification 263,198 is referred to.