The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Oct. 23, 1990
Filed:
Aug. 21, 1989
Kenneth D Goetz, Bartlesville, OK (US);
Bradley L Munro, Bartlesville, OK (US);
Phillips Friedman Company, Bartlesville, OK (US);
Abstract
A process for recovering N-methyl-2-pyrrolidone from an effluent stream in a poly(arylene sulfide) process containing N-methyl-2-pyrrolidone contaminated with acidic compounds and high boiling contaminants by contacting the kettle liquid from a heavies fractionation zone with an inorganic compound selected from the group consisting of alkaline earth oxides and alkaline earth hydroxides in an amount effective to reduce the acidic compound content of the kettle liquid, and introducing the treated kettle liquid into a thin film evaporation zone to produce an overhead product containing N-methyl-2-pyrrolidone and a bottoms stream containing N-methyl-2-pyrrolidone soluble reaction products of the acidic compounds with the inorganic compound, unreacted acidic compounds and high boiling contaminants. The thin film evaporation zone overhead product stream can be recycled to the heavies fractionation zone, or introduced to an N-methyl-2-pyrrolidone recovery zone and fractionated to produce an overhead product stream consisting essentially of N-methyl-2-pyrrolidone and an intermediate heavies bottoms stream. In a further embodiment, the N-methyl-2-pyrrolidone recovery zone overhead product can be recycled to the heavies fractionation zone.