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. 25, 1977
Filed:
Nov. 20, 1974
Ferdinand List, Marl, DT;
Wilfried Uhlenbrock, Bochum, DT;
Norbert Wilke, Marl, DT;
Kurt Wember, Marl, DT;
Chemische Werke Huls Aktiengesellschaft, Marl, DT;
Abstract
The process of recovering methanolic mother liquor obtained by the esterification of terephthalic acid with methanol, where the terephthalic acid may be unprepurified, is improved by adjusting to a specific gravity of about 0.85 - 0.98 by addition of water and/or methanol distillate, a mother liquor containing esterification water and dissolved solids at a concentration of about 1.0 to 6.0 percent by weight and cooling the mother liquor from a temperature of about 65.degree. - 85.degree. C to a temperature of about 10.degree. - 30.degree. C to separate the solids and remove the separated solids. The separated solids may be recycled into the esterification reaction and the unseparated solids may be recycled for oxidation to terephthalic acid following distillation to remove the methanol.