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:
May. 17, 1994
Filed:
May. 20, 1993
Rhone-Poulenc Chimie, Courbevoie, FR;
Abstract
Dicarboxylic acids, e.g., adipic acid, are prepared by reactively distilling and hydrolyzing admixture of a C.sub.1 -C.sub.4 alkyl aliphatic dicarboxylate and water, e.g., dimethyl adipate/water admixture, in liquid phase, in a distillation column, the lower end of which distillation column being charged with a gel of a crosslinked styrene/divinylbenzene resin bearing sulfonic acid substituents, the amount by weight of divinylbenzene comprising such resin ranging from 1% to 12% based on the total weight thereof and such resin having an exchange capacity of from 3 to 6.5 milliequivalents H.sup.+ /gram of dry resin, and including introducing the dicarboxylate/water admixture into the middle region of the column, withdrawing dicarboxylic acid from the base thereof and overhead distilling the alcohol of hydrolysis.