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. 10, 1983
Filed:
Oct. 19, 1981
Udo Rudolph, Krefeld, DE;
Dieter Freitag, Krefeld, DE;
Ludwig Bottenbruch, Krefeld, DE;
Manfred Schmidt, Krefeld, DE;
Bayer Aktiengesellschaft, Leverkusen, DE;
Abstract
A single-stage process for the production of pure, particularly sulphur-free, aromatic carboxylic acid chlorides by reacting an aromatic carboxylic acid containing from 1 to 3 carboxyl groups or a corresponding mixture of aromatic carboxylic acids with thionyl chloride in the presence of a catalyst, wherein tertiary phosphine oxides or their reaction products with thionyl chloride and/or the acid chloride to be formed are used as catalysts, and the use of the aromatic dicarboxylic acid dichlorides and tricarboxylic acid trichlorides obtained for the production of polycondensates.