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:
Sep. 14, 1993
Filed:
Nov. 15, 1991
Ube Industries, Ltd., Yamaguchi, JP;
Abstract
Disclosed is an ion exchange purification method of an aqueous caprolactam solution in a process for producing caprolactam and laurolactam by subjecting a mixture of cyclohexanone oxime and cyclododecanone oxime to Beckmann rearrangement in the presence of sulfuric acid and fuming sulfuric acid, which comprises, after neutralization of the rearrangement reaction products, and first extraction thereof with an organic solvent and second extraction of the first extract with water to obtain a second extract of an aqueous caprolactam solution, treating the aqueous caprolactam solution obtained by extraction with an organic solvent immiscible with water with a strongly acidic cation exchange resin, and subsequently with a weakly basic anion exchange resin or further with a strongly basic anion exchange resin.