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:
Jan. 03, 1978
Filed:
Sep. 08, 1976
Manfred Schroeder, Marl, DT;
Chemische Werke Huels Aktiengesellschaft, Marl, DT;
Abstract
A process for the production of pure diglycolic acid by oxidation of diethylene glycol with nitric acid, comprises the steps of: A. cooling the reaction mixture formed during the oxidation to a temperature of -10.degree. to +25.degree. C. and separating a first quantity of thus-crystallized diglycolic acid; B. concentrating the first mother liquor at 5 - 530 millibars to a concentration of 35-45% by weight of HNO.sub.3 and cooling to a temperature of -10.degree. to +25.degree. C.; c. separating a further quantity of thus-crystallized diglycolic acid; and D. recycling the remaining second mother liquor to the reactor for oxidizing diethylene glycol with nitric acid.