Basf Aktiengesellschaft

Thomas Domschke

Ulrich Steinbrenner

Christoph Sigwart

Martin Merger

Martin Haubner

Gerd Kaibel

Rolf-Hartmuth Fischer

Kaspar Bott

Friedrich Sauer

Christian Tragut

Stefan Käshammer

Tillmann Faust

Gerd Bohner

Petra Deckert

Achim Gerstlauer

Andreas Joa

Klaus Steinebrunner

Michael Bohn

Georg Grossmann

The invention relates to a method for the separation of ascorbic acid from a mixture containing ascorbic acid and-keto-L-gulonic acid in a polar, preferably aqueous solvent, by means of liquid/liquid extraction using an amide. The method preferably also comprises steps for the back-extraction of the ascorbic acid, recycling of the extraction solvent and/or the back extraction solvent and for isolation of the ascorbic acid from the back extraction solvent. The invention further relates to a method for the production of ascorbic acid from KGA and isolation of the ascorbic acid so produced.

Method for the separation of ascorbic acid from a polar solvent containing ascorbic acid and 2-keto-L-gulonic acid

The invention relates to a method for producing 2-keto-L-gulonic acid-C&#x2013;Calkyl ester by esterifying 2-keto-L-gulonic acid (KGS) with an unsaturated, branched or unbranched C&#x2013;Calcohol. The inventive method is characterized by the fact that an aqueous KGS solution is reacted with a C&#x2013;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&#x2013;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&#xb0; C. In another embodiment, the produced KGS ester is reacted in one or several additional steps so as to obtain L-ascorbic acid.

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In a process for the single-stage preparation of polytetrahydrofuran and/or tetrahydrofuran copolymers having a mean molecular weight of from 650 to 5000 dalton by polymerization of tetrahydrofuran over an acid catalyst in the presence of at least one telogen and/or comonomer, the telogen and/or comonomer is added at at least two addition points in different segments of the polymerization apparatus.

Method for producing polytetrahydrofuran

Method for the single-step production of polytetrahydrofuran and tetrahydrofuran copolymers

A process for the thermal treatment of incombustible liquids in a combustion space of a combustion apparatus by contacting the incombustible liquid with a supplementary fuel in the combustion space in the presence of at least one reactive gas. The process of the invention comprises feeding the incombustible liquid and the supplementary fuel into the combustion space (,) at different points, mixing the incombustible liquid with at least one reactive gas and the supplementary fuel with at least one inert gas prior to the contacting, and vaporizing the incombustible liquid and supplementary fuel prior to the contacting in the combustion space. The advantage of this invention is that environmentally harmful waste waters in particular are disposed of by burning these using a supplementary fuel. The required amounts of supplementary fuel are minimal in the process and only small amounts of nitrogen oxides, carbon monoxide and soot are generated.

Thermal treatment of incombustible liquids

Preparation of crystalline n-methylol-(meth) acrylamide

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Speyer, Germany

Thomas Domschke