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:
Aug. 03, 2004
Filed:
Oct. 16, 2001
Anna Giatti, Arnhem, NL;
Fred Korpel, Roosendaal, NL;
Roger Keranen Rains, Richfield, OH (US);
Gerrit Jan Boerman, Deventer, NL;
Flexsys B.V., Deventer, NL;
Abstract
The present invention relates to a process for improving the purity of a composition comprising a quaternary ammonium hydroxide comprising the steps of (a) providing an electrolysis cell which comprises an anolyte compartment containing an anode, a catholyte compartment containing a cathode, and at least one intermediate compartment, said at least one intermediate compartment being separated from the anolyte and catholyte compartments by cation selective membranes, (b) charging water, optionally containing a supporting electrolyte, to the anolyte compartment, charging water, optionally containing a quaternary ammonium hydroxide, to the catholyte compartment, and charging the composition comprising the quaternary ammonium hydroxide to be purified to the intermediate compartment, (c) passing a current through the electrolysis cell to produce a purified aqueous quaternary ammonium hydroxide solution in the catholyte compartment, and (d) recovering the purified aqueous quaternary ammonium hydroxide solution from the catholyte compartment. The process is particularly suitable for improving the purity of an aqueous solution comprising tetramethylammonium hydroxide which has been used in the production of 4-aminodiphenylamine for a number of reaction cycles.