Patent ID: 6462201
Filing Date: 2002-10-08
Classification: C07D

Abstract:
A single stage process, with recycle, for making an N-vinyl lactam which comprises:(a) forming a reaction mixture by saturating a non-aqueous liquid mixture of about 10 to 99.5% by wt of a lactam selected from the group consisting of 2-pyrrolidone (2-Py) and caprolactam (CL), 0 to 90% by wt of vinyl pyrrolidone (VP) or vinyl caprolactam (VCL), 0.1 to 5% by wt of an alkali metal salt of said lactam, or equivalent thereof, as a catalyst in said process, with acetylene at a temperature of about 5 to 50Â° C. and at an acetylene pressure of about 5 to 100 psig, thereby to provide an acetylene concentration in said mixture of about 0.5 to 3% by wt, (b) pumping the reaction mixture at a pressure of about 200 to 3000 psig into a reactor heated to a temperature of about 90 to 200Â° C., (c) reacting the mixture as a single liquid phase to produce the desired N-vinylpyrrolidone or N-vinyl caprolactam at a high reaction rate and selectivity and at a predetermined conversion, (d) cooling the reaction product, (e) withdrawing a predetermined portion of the cooled reaction product mixture, (f) recirculating the rest of the cooled reaction product into step (a), and (g) continuously feeding additional lactam and catalyst into step (a).