Basf Aktiengesellschaft

Badische Anilin- & Soda-fabrik Aktiengesellschaft

Gerd Duembgen

Richard Krabetz

Franz Merger

Fritz Thiessen

Heinz Engelbach

Carl-Heinz Willersinn

Gerd Fouquet

Friedbert Nees

Ulrich Lebert

Matthias Schwarzmann

Franz J Broecker

Walter Frey

Ulrich Hammon

Herbert Vogel

Karl-Heinz Boehning

Peter Bassler

Karl Baer

Ernest Miesen

Gerhard Pforr

Erfried Voelkl

Guenter Weber

Norbert Scholz

Gottfried Schlichthaerle

Walter Herrmann

Gerd-Juergen Engert

Ekhart Lucas

Wolfgang Pies

Helmut Glietenberg

Walter Beitelschmidt

Herbert Vogal

Michael Jaeger

Hermann Spitzl

Compositions of the formula Mo.sub.12 P.sub.a V.sub.b X.sup.1 c X.sup.2

Compositions of the formula MO.sub.12 P.sub.a V.sub.b X.sup.1.sub.c

Methacrylic acid can be prepared with advantage by gas phase oxidation of methacrolein or isobutyraldehyde over Mo- and P-containing catalysts at from 250.degree. to 400.degree. C. with cooling of the hot reaction gas to below 100.degree. C., absorption of the methacrylic acid in a water-operated absorption column, at below 100.degree. C. and partial recycling into the oxidation reactor after admixture of methacrolein or isobutyraldehyde and oxygen by feeding a quantity of methacrolein or isobutyraldehyde equal to the quantity of methacrolein or isobutyraldehyde consumed in the reaction in liquid form together with a polymerization inhibitor into the reactor gas in the lower two-thirds of the absorber column and upstream of the feed point for the fresh methacrolein or isobutyraldehyde or down-stream of the absorption column splitting off the reactor off-gas a side stream which is washed in a wash column operated with water at &lt;10.degree. C. to remove unconverted methacrolein or isobutyraldehyde which is fed as an aqueous solution to the top of the absorption column.

Preparation of methacrylic acid

Oxidation catalysts of the general formula

Process and catalyst for the preparation of methacrylic acid

A catalyst which is free from alkali metal compounds and alkaline earth metal compounds, contains palladium and lead as active constituents and is supported on a carrier which contains two or more of the oxides ZnO, Al.sub.2 O.sub.3, La.sub.2 O.sub.3 and TiO.sub.2, and the use of this catalyst for the preparation of methyl methacrylate from methacrolein, methanol and oxygen.

Preparation of methyl methacrylate from methacrolein

Methanol is prepared by catalytic conversion of a synthesis gas mixture, containing hydrogen, carbon monoxide, carbon dioxide and/or water, at from 200.degree. to 320.degree. C. and under from 30 to 300 bar in adiabatic and/or isothermal reactions in the presence of a catalyst containing copper and zinc, by a process in which the fresh catalyst is reduced with a hydrogen-containing gas before the start-up of the process, and then the synthesis is started under conventional conditions and is continued until the formation of methanol in the reaction zone has declined substantially, after which the reaction is interrupted and the catalyst is regenerated.

Preparation of methanol

Preparation of methacrylic acid and catalyst therefor

Catalysts for the preparation of carboxylates from an aldehyde and an alkanol in the presence of oxygen, which contain palladium and lead as active components, these being present on a carrier containing zinc oxide, and the palladium being applied as a palladium salt in a solution containing hydrochloric acid and then being liberated by reduction, and whose carrier consists solely of zinc oxide, are particularly active and selective.

Catalyst for the preparation of methyl methacrylate

.alpha.-Alkylacroleins are prepared by a process wherein an alkanal is reacted with formaldehyde in the presence of a secondary amine and in the presence or absence, of an acid, in the liquid phase, under superatmospheric pressure and at above 150.degree. C., for not more than 25 minutes. The .alpha.-alkylacroleins obtainable by the process are useful starting materials for dyes, drugs and pesticides.

Process for the preparation of .alpha.-alkylacroleins

To destroy phosgene contained in gases, the phosgene is decomposed catalytically in the presence of active carbon by hydrolysis with water vapor, in the absence of liquid water, at above the dew point of water.

Process for destroying phosgene

Acrolein and methacrolein are prepared advantageously by oxidizing propylene or isobutylene, respectively, with an oxygen-containing gas mixture under conventional conditions over a supported catalyst possessing a firmly adhering coating, from 150 to 1,500 .mu.m thick, which contains calcined catalytic material based on molybdenum oxide and has a carrier core with a surface area of less than 15 m.sup.2 /g and a diameter of more than 100 .mu.m, if a coated catalyst is used which has been prepared by applying calcined catalytic material having a particle size of from 0.1 to 300 .mu.m, in an amount of from 1 to 40 g/min/liter of carrier and water in a weight ratio of catalytic material to water of from 1:1 to 8:1, continuously and separately from one another, each at a constant speed, at below 100.degree. C. to vigorously agitated carrier particles which may or may not have been premoistened with water in an amount of up to 95% of the water absorbency of the particles, the prepartion of the catalyst being carried out in such a way that the water content of the coating which forms is less than the maximum degree of saturation of the catalytic material.

Preparation of .alpha.,.beta.-olefinically unsaturated aldehydes of 3 or

Catalysts which consist of a molded carrier, the surface of which is coated with an active catalyst composition of the general formula Mo.sub.12 A.sub.a B.sub.b C.sub.c D.sub.d O.sub.x, where A is V and/or W, B is Cu and/or Fe and/or Mn and/or Ni and/or Cr, C is Nb and/or Ta and/or Bi and/or Sb and/or Sn and/or Th and/or Ce and/or U, D is Li and/or Na and/or K and/or Rb and/or Cs and/or Tl and a is from 0.1 to 18, b is from 0 to 8, c is from 0 to 10, d is from 0 to 2 and x is from 36 to 135, which are particularly active and selective for the oxidation of acrolein and methacrolein with oxygen-containing gases to give acrylic acid and methacrylic acid, respectively, are obtained by first manufacturing the catalyst composition, before applying it to the carrier, from thermally easily decomposed salts of the components by mixing aqueous solutions, slurries or moist solid masses of the salts of the components, drying the mixture and calcining the dried composition at from 140.degree. to 600.degree. C., then milling it to a particle size of less than 150 .mu.m and thereafter applying it, as a mixture with water, as a layer from 10 to 1,500 .mu.m thick, to the premolded carrier, which has a rough surface.

Catalyst for the oxidation of acrolein and methacrolein to acrylic acid

.gamma.-Butyrolactone is manufactured by hydrogenating maleic anhydride in the presence of butyrolactone as the solvent. The hydrogenated reaction mixture, which contains butyrolactone, succinic anhydride and succinic acid, is fractionated in a thin film evaporator.

Manufacture of .gamma.-butyrolactone from maleic anhydride

In the oxidation of propylene and/or acrolein, high-boiling or non-volatile byproducts are separated from the solvents used for absorbing the acrylic acid by treating the said solvents laden with byproducts with the hot reaction gases in such amounts that the major portion of the solvents evaporates, the residual solvent containing a high percentage of said byproducts then being discarded or worked up.

Method of separating high-boiling or non-volatile materials

In the oxidation of .alpha.-olefins in the gas phase to .alpha.,.beta.-olefinically unsaturated aldehydes and carboxylic acids with molecular oxygen in the presence of an inert gas using a catalyst containing molybdenum and bismuth with elements as oxides or mixed oxides at from 280.degree. to 450.degree. C a content of indium and/or aluminum and/or lanthanum and/or gallium as oxide or mixed oxide results in an improvement in the conversion and/or activity and/or life of the catalyst.

Catalytic oxidation of .alpha.-olefins

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Dannstadt-Schauernheim, Germany

Gerd Duembgen