Evonik Degussa Gmbh

Evonik Operations Gmbh

Evonik Industries Ag

Benjamin Fonfe

Harald Jakob

Stephan Kretz

Sebastian Fuss

Martin Koerfer

Chiu Kee Cheung

Nadine Duerr

Andreas Doerflein

Hans Joachim Hasselbach

Wolfgang Boeck

Pablo Zacchi

Caspar Heinrich Finkeldei

Chuanhua He

Ali Hartwig

Christoph Weckbecker

Dieter Buss

Martin Körfer

Martin Steurenthaler

Wolfgang Böck

Michael R Rinner

Frank Wilz

Xiangyu Yang

Markus Held

Joachim Hans Hasselbach

Andreas DÖRFLEIN

The present invention relates to a process for the preparation of an alkanesulfonic acid by oxidation of a sulfur containing starting compound with an oxygen containing fluid, wherein the sulfur containing starting compound is provided in a reaction system, comprising a reaction vessel () with an expansion vessel () on its top, wherein the reaction vessel and the expansion vessel are connected to allow a flow of a fluid stream from the reaction vessel into the expansion vessel.

Process for the preparation of an alkanesulfonic acid

The present invention relates to a process for operating a plant for preparing an alkanesulfonic acid, wherein said alkanesulfonic acid is prepared by oxidation of an alkylmercaptan, dialkydisulfide and/or dialkylpolysulfide and the one or more alkyl radicals of the alkylmercaptan, dialkydisulfide and/or dialkylpolysulfide are identical with the alkyl radical of the alkylsulfonic acid to be prepared, characterized in that the oxidation is performed in the presence of an at least stoichiometric amount of an oxoacid of nitrogen, e.g. nitric acid, relative to the amount of said alkylmercaptan, dialkyldisulfide and/or dialkylpolysulfide during the start-up phase of the plant of the plant, wherein the start up phase comprises the steps adding an oxoacid of nitrogen to the reactor, adding sulfur-containing reactant progressively so that it is converted to alkanesulfonic acid, filling up the compile volume of the reactor by adding progressively sulfur-containing reactant and if needed oxoacid of nitrogen to make sure that it is in excess, once the reactor is full, transitioning out of the start-up phase by adding an oxygen containing fluid, and during the running phase, keeping the reaction volume full by balancing the volume of product withdrawn with the volume of sulfur-containing reactant added.

Process for operating a plant for preparing an alkanesulfonic acid

A method for determining dimethyl disulphide proceeds by carrying out a chromatographic separation of an analyte containing at least dimethyl disulphide and methanesulphonic acid, and determining the dimethyl disulphide by pulsed amperometric detection.

Method for determining dimethyl disulphide

The present invention relates to a process for preparing alkanesulphonic acid by oxidizing an alkyl mercaptan, a dialkyl disulphide and/or a dialkyl polysulphide having three to nine sulphur atoms with an oxidizing agent, wherein additional oxidizing agent is fed into the oxidation if as yet unoxidized alkyl mercaptan and/or unoxidized dialkyl disulphide and/or at least one intermediate from the oxidation of the dialkyl disulphide and/or of the dialkyl polysulphide is present in the reaction output, and a corresponding apparatus for performance of oxidation reactions.

Process for preparing an alkanesulphonic acid

The present invention relates to a catalyst for oxidation reactions, particularly for oxidation of mercaptan dialkyldisulfides and/or dialklypolysulfides with oxygen to alkanesulfonic acids.

Catalyst for oxidation reactions, a method for its preparation and the use thereof

The present invention relates to a process for preparing alkanesulfonic acids from dialkyl disulfides with nitric acid and oxygen.

Process for preparing alkanesulfonic acids

An alkyl mercaptan is prepared by reacting an aliphatic alcohol with hydrogen sulfide in the presence of a heterogeneous catalyst at varying temperatures.

Process for the preparation of alkyl mercaptans

The present invention relates to a catalyst which comprises a support material and an oxidic composition containing at least one alkali metal and tungsten, a process for producing such catalysts and also a process for preparing alkyl mercaptans by reaction of alkanols with hydrogen sulphide in the presence of such a catalyst.

Catalyst for the synthesis of alkyl mercaptans and process for producing it

A process for preparing methylmercaptopropionaldehyde in a single reaction unit, is provided. According to the preferred embodiment, the process comprises, simultaneously contacting a gaseous mixture comprising acrolein with a liquid mixture comprising methylmercaptopropionaldehyde, methyl mercaptan, a catalyst and methylmercaptopropionaldehyde methyl thiohemiacetal in the reactive absorber; absorbing the acrolein from the gaseous mixture into the liquid mixture; reacting the absorbed acrolein with the methyl mercaptan or the methylmercaptopropionaldehyde methyl thiohemiacetal to obtain methylmercapto-propionaldehyde; removing gaseous impurities and by-products from the liquid mixture; and separating the obtained methylmercaptopropionaldehyde product from the reactive absorber, directing a portion of the separated product to storage or further processing and recycling the remaining portion to the reactive absorber; wherein the methyl mercaptan optionally comprises dimethyl sulfide or dimethyl ether.

Process for preparing methylmercaptopropionaldehyde

A storage stable mixture containing 86 to 97% by weight of 2-hydroxy-4-methylthiobutyronitrile, 2 to 14% by weight of water, 0.05 to 0.5% by weight of HCN and having a pH of 1 to 4, measured using a pH electrode at 23&#xb0; C. is provided. A method to produce the storage stable mixture and its use in manufacture of DL-methionine or 2-hydroxy-4-methylthiobutyric acid is also provided.

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Frankfurt-am-Main, Germany

Benjamin Fonfe