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:
Apr. 20, 1982
Filed:
Jul. 25, 1980
Christian Wandrey, Julich, DE;
Rolf Wichmann, Julich, DE;
Wolfgang Leuchtenberger, Bruchkobel, DE;
Maria-Regina Kula, Wolfenbuttel, DE;
Andreas Buckmann, Braunschweig-Stockheim, DE;
Degussa AG, Frankfurt, DE;
Abstract
Water soluble .alpha.-ketocarboxylic acids are continuously converted in a membrane reactor into the corresponding .alpha.-hydrocarboxylic acids. The conversion takes place in the presence of a substrate specific dehydrogenase and of a nicotinamide-adenine-dinucleotide (NAD.sup.+ /NADH) enlarged in molecular weight through linkage to a water soluble polymer as coenzyme. Simultaneously NADH is regenerated continuously from NAD.sup.+ in presence of a formate dehydrogenase and from formate ion. The membrane must have a mean pore diameter of 1 to 3 nm. As coenzyme there is employed 0.1 to 10 mmol/l of NAD.sup.+ /NADH present bound to a water soluble polymer having an average molecular weight between 500 and 50,000. There is continuously supplied to the reactor a substrate stream which contains 50 to 100% of the maximum amount soluble, but not over 2,000 mmol/l, of the reacting .alpha.-ketocarboxylic acid in the form of a water soluble salt and 100 to 6,000 mmol/l of a formate. There is maintained over the membrane a differential pressure of 0.1 to 15 bar. There is continuously drawn off behind the membrane a filtrate stream containing the .alpha.-hydroxy acid formed.