GB856822A - Preparation of pyrrolidinone - Google Patents

Abstract

Pyrrolidinone is prepared by catalytic hydrogenation of a C1-4 alkyl beta-cyano propionate by mixing a nickel hydrogenation catalyst and an inert organic solvent, supplying hydrogen under elevated pressure to the resulting mixture, agitating and heating the mixture under hydrogen to a temperature of 150 DEG -260 DEG C., gradually adding the alkyl cyano propionate to the agitated heated mixture and holding the temperature of the reaction mixture between 150 DEG and 300 DEG C. under a total pressure of at least 200 p.s.i. while the alkyl cyano propionate is being added to the reaction mixture. The catalyst may be Raney nickel or reduced nickel on silica or atomaceous earth. The solvent may be pyrrolidinone itself, an alkanol or an ether such as butyl ether. Hydrogen may be supplied initially at 30-300 p.s.i. and thereafter as necessary to maintain the desired total pressure. Alkanol formed in the reaction may be vented off. The reaction may be effected in the presence of a small quantity of ammonia, e.g. 0,1-0,5 mole per mole of alkyl cyano propionate. Examples 1-3 describe the batchwise conversion of methyl, ethyl and butyl b -cyano propionates. In example 4, the methyl ester is converted to pyrrolidinone by a continuous process wherein an autoclave is charged with methanol and Ni catalyst and heated under hydrogen pressure whereupon a feed of the methyl ester, methanol and ammonia is continuously fed in with make-up hydrogen while product mixture is continuously withdrawn via a micro-metallic filter within the autoclave.