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:
Nov. 02, 1999
Filed:
Sep. 08, 1998
Manfred Bergfeld, Erlenbach, DE;
Ludwig Eisenhuth, Obernburg, DE;
Akzo Nobel N.V., , US;
Abstract
A process is provided for preparing polyhydroxycarboxylic acids by the selective oxidation of di-, tri-, oligo- and polysaccharides in an alkaline medium using an oxygenous gas in the presence of palladium on a carrier as catalyst and bismuth as promoter at a palladium concentration in the reaction mixture of at least about 40 mg/l and a molar ratio of bismuth to palladium in the range of from about 1:5 to about 1:40, in which process towards the end of the reaction, as soon as a strong increase is observed in the oxygen concentration in the liquid phase, the oxygen supply is reduced until it is not more than about 20 ppm. In this manner, virtually all of the polysaccharide added beforehand is converted into the desired end product without an unacceptably high concentration of bismuth in the end product.