Degussa Aktiengesellschaft

Evonik Degussa Gmbh

Degussa - Huls Ag

Wolfgang Boeck

Dietrich Arntz

Joerg Sauer

Willi Hofen

Stephan Rautenberg

Werner Burkhardt

Wolfgang Taugner

Hans Joachim Hasselbach

Martin Koerfer

Guenter Prescher

Stephan Kretz

Ralf Goedecke

Lukas M Von Hippel

Benjamin Fonfe

Raymund Sonnenschein

Pablo Zacchi

Caspar Heinrich Finkeldei

Mathias Hoepp

Adolf Schaefer-Sindlinger

Udo Gruber

Stephan Bartsch

Klaus Raible

Andreas Bosse-Plois

The invention relates to a process for separating acrolein from the process gas of a heterogeneously catalyzed oxidation of propene by means of atmospheric oxygen, wherein high boilers (including acrylic acid) are firstly separated off from the process gas by means of quenching and technical-grade acrolein having small proportions of low boilers is then obtained by means of absorption and subsequent distillation. Small amounts of a solvent by means of which, in particular, oligomers formed are separated off and the tendency for foam to be formed in the apparatuses or columns is reduced is added in the columns and heat exchangers in the work-up process. The solvent is, according to the invention, separated off and recycled in the form of an organic phase in-situ within the existing process.

Method for removing acrolein from the process gas of a heterogeneously catalysed oxidation of propene

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 catalyst for the synthesis of methyl mercaptan from hydrogen sulfide and methanol as well as a process for preparation of the catalyst. The catalyst is an active aluminum oxide onto which 5 to 25% by weight potassium tungstate is deposited as an activator. A two-stage impregnation with intermediate drying produces a catalyst which exhibits distinctly better selectivity for formation of methyl mercaptan than catalysts obtained by single-stage impregnation.

Catalyst, process for its preparation, and use for synthesis of methyl

A process for continuous production of methyl mercaptan by catalytic reaction of methanol and hydrogen sulfide. Significant improvements in the pretreatment of the feed gas mixture and in utilization of the heat of reaction and the heat content of the product gas mixture. The energy required to vaporize the methanol is derived partly from utilization of the heat of compression of the hydrogen sulfide gas and from the heat content of the product gas leaving the reactor. The heat of reaction is utilized to heat the feed gas mixture to the reaction temperature, with the help of an external gas heater.

Process for continuous production of methyl mercaptan

A process for separating the product gas mixture from the catalytic synthesis of methyl mercaptan. Because of improved separation of the product gas mixture into its components, less hydrogen sulfide and methyl mercaptan are lost in discharging the inert gases than in the known process. The inert gases can be burned without after-treatment of the exhaust gas. Likewise, the process water that is discharged is less contaminated with polysulfides.

Process for separating the product gas mixture from the catalytic

A catalyst for the synthesis of methyl mercaptan from hydrogen sulfide and methanol, as well as a process for preparing the catalyst. The catalyst contains active aluminum oxide on which 15% to 40% by weight cesium tungstate is deposited as the activator. The activator, cesium tungstate, gives an unexpected increase in activity and selectivity as compared with potassium tungstate, which is used exclusively at the present state of the art.

Process for the production of 2-vinyl-1,3-dioxolane reacting acrolein with ethylene glycol in the presence of a solid, acidic catalyst and recovery of the reaction mixture. Selectivity may be increased in comparison with known prior art processes by performing the reaction in the presence of a solid acidic catalyst at a temperature of below 50.degree. C.; the reaction mixture, from which the catalyst has been removed, is treated by extraction using an organic solvent which substantially does not dissolve ethylene glycol and has a boiling point of above 130.degree. C.; the two phases obtained on extraction are treated for recovery by distillation and recovered educts and the organic solvent are recycled.

Process for the production of 2-vinyl-1,3-dioxolane

Mixed cyclic acrolein glycerol acetals can be obtained by reacting acrolein with glycerol in the presence of a solid acidic catalyst and by a distillation workup in a higher space-time yield and in very high selectivity in comparison to the state of the art if the reaction is carried out in the presence of the reaction mixture as solvent, which mixture consists essentially of acrolein, glycerol, cyclic acrolein glycerol acetals and water, and in the absence of heterogeneous solvents and, to the extent necessary, the reaction mixture freed of catalyst is compounded prior to being worked up by distillation with such an amount of pH-increasing substance that it exhibits a pH in a range of 4.5 to 7 in tenfold dilution with water. The reaction preferably takes place at 10.degree. to 30.degree. C. using strongly acidic organic or inorganic ion exchangers.

Method of producing mixtures of cyclic acrolein glycerol acetals

A catalyst is described for the production of unsaturated aldehydes by means of oxidation with a oxygen-containing gas where an active mass, containing at least the elements Mo, Bi, P and O, as well as Si-containing carrier material, is used in the form of a catalyst body with a certain ratio between the outer surface and the volume and with a defined extent in terms of space, porosity, density, specific surface, breaking strength, abrasion, and gas through-flow capability. Also described is a method of making the catalyst.

Catalyst for catalytic gas phase oxidation of olefins into unsaturated

The present invention relates to a process for the production of acrolein by catalytic gas-phase oxidation of propene with air in the presence of steam and an inert gas or waste gas from the reaction, the starting materials being passed in defined quantitative ratios at 300.degree. to 380.degree. C. under 1.4 to 2.2 bar pressure over a catalyst containing the combination of elements MoFeCoNiBiP(As)K(Rb,Cs)SmSiO in the form of a bed of individual elements, the catalyst elements fulfilling certain geometric conditions and a number of critical physico-chemical parameters and a specific load of 2 to 8 mol propene/dm.sup.3 catalyst bed/h being adjusted.

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Langenselbold, Germany

Wolfgang Boeck