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:
Aug. 15, 2006
Filed:
Nov. 07, 2003
Thomas Domschke, Speyer, DE;
Martin Merger, Ludwigshafen, DE;
Georg Grossmann, Mannheim, DE;
Tillmann Faust, Weisenheim, DE;
Thomas Domschke, Speyer, DE;
Martin Merger, Ludwigshafen, DE;
Georg Grossmann, Mannheim, DE;
Tillmann Faust, Weisenheim, DE;
BASF Aktiengesellschaft, Ludwigshafen, DE;
Abstract
The invention relates to a method for producing 2-keto-L-gulonic acid-C–Calkyl ester by esterifying 2-keto-L-gulonic acid (KGS) with an unsaturated, branched or unbranched C–Calcohol. The inventive method is characterized by the fact that an aqueous KGS solution is reacted with a C–Calcohol up to an esterification degree of 20 to 70 percent in a pre-esterification process carried out under acidic catalysis conditions; and the obtained product is dehydrogenated with an unsaturated, branched or unbranched C–Calcohol in a continuous rectification device, whereby the esterification reaction continues, n-butanol preferably being used as the alkyl alcohol. In a preferred embodiment, the aqueous KGS solution is concentrated up to or beyond the limit of solubility prior to the esterification process, preferably by catalyzing a homogeneous or heterogeneous catalyst, especially sulfonic acid, at temperatures of 50 to 120° C. In another embodiment, the produced KGS ester is reacted in one or several additional steps so as to obtain L-ascorbic acid.