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. 04, 1976
Filed:
Feb. 12, 1975
Klaus Gehrmann, Erfstadt Lechenich, DT;
Heinz Erpenbach, Surth near Cologne, DT;
Georg Kohl, Hurth-Burbach, DT;
Hans Klaus Kuebbeler, Surth near Cologne, DT;
Hoechst Aktiengesellschaft, Frankfurt am Main, DT;
Abstract
Monomeric acrylic acid is recovered from residues originating from processed crude acrylic acid and containing .beta.-acryloyloxypropionic acid, .beta.-acetoxypropionic acid, hydracrylic acid, dihydracrylic acid and polymeric hydracrylic acid. To this end, the residues are heated to temperatures within the range 130.degree. and 250.degree.C under pressures within the range 0.01 and 1 atmosphere absolute in contact with catalysts selected from alkali metal or alkaline earth metal carboxylates, phosphates or borates, or from alkali metal or alkaline earth metal compounds producing carboxylates together with the carboxylic acids being contained in the residues.