Basf Aktiengesellschaft

Herbert Exner

Toni Dockner

Karl Gerhard Baur

Albrecht Dams

Gerhard Nestler

Holger Herbst

Herbert Vogel

Christiane Potthoff

Alexander Weck

Heinrich Aichinger

Gabriele Iffland

Hans-Josef Sterzel

Andreas Tenten

Detlef Kratz

Hans-Peter Neumann

Hans Martan

Helmut Lermer

Ulrich Annen

Michael Fried

Ulrich Rauh

Willi Schmidt

Gerd Bohner

Matthias Geisendorfer

Brudermuller

Crude (meth)acrylic acid is purified by a process in which a primary amine compound and an organic sulfonic acid are added to the crude (meth)acrylic acid and the latter is then worked up by distillation.

Purification of crude (meth) acrylic acid

In a process and an apparatus for the continuous preparation of alkyl esters of (meth)acrylic acid by reacting (meth)acrylic acid with alkanols having from 1 to 5 carbon atoms in a homogeneous, liquid, solvent-free phase at elevated temperature and in the presence of an acid esterification catalyst, in which the (meth)acrylic acid, the alkanol and the catalyst are fed to a reaction zone, the water formed is removed by rectification during a residence time as constituent of a mixture comprising alkanol in a rectification unit superposed on the reaction zone, the distillate thus obtained is separated into an organic phase comprising alkanol and an aqueous phase comprising water, the organic phase is returned to the rectification unit, the reaction mixture is discharged from the reaction zone and conveyed into a distillative separation zone comprising further rectification units and in the latter the alkyl (meth)acrylate formed is separated off.

Continuous preparation of alkyl esters of (meth) acrylic acid

In a process and an apparatus for the continuous preparation of alkyl esters of (meth)acrylic acid by reacting (meth)acrylic acid and monohydric alkanols of 1 to 8 carbon atoms in the homogeneous, liquid, solvent-free phase at elevated temperatures and in the presence of an acidic esterification catalyst, by feeding the (meth)acrylic acid, the alkanol and the acid catalyst continuously to a reaction zone, the reaction zone consists of a cascade of at least two reaction regions connected in series, and the discharge stream of one reaction region forms a feed stream of a downstream reaction region. The cascade may have from two to four reaction regions is spatially separated from one another.

Continuous preparation of alkyl esters of (meth)acrylic acid and

In the process for the continuous preparation of alkyl esters of (meth)acrylic acid by reacting (meth)acrylic acid with monohydric alkanols having from 1 to 8 carbon atoms in the presence of an acid esterification catalyst in a reaction zone, there is discharged from the reaction zone a product mixture which comprises the alkyl (meth)acrylate formed, the catalyst and the by-products formed during the course of the esterification having boiling points higher than that of the alkyl (meth)acrylate, and from which the alkyl (meth)acrylate is separated by distillation in a separation zone. The product mixture discharged from the reaction zone is fed to a rectification unit (I), in this unit the product mixture discharged is separated by rectification into at least one product (I) comprising the alkyl ester of (meth)acrylic acid and a product (II) comprising the catalyst, the product (I) is fed to a further rectification unit (II) and in this the alkyl ester of (meth)acrylic acid is separated off by rectification.

Continuous preparation of alkyl esters of (meth)acrylic acid

In a process and an apparatus for the continuous preparation of alkyl esters of (meth)acrylic acid by reacting (meth)acrylic acid and monohydric alkanols of 1 to 8 carbon atoms in the homogeneous, liquid, solvent-free phase at elevated temperatures and in the presence of an acidic esterification catalyst, by feeding the (meth)acrylic acid, the alkanol and the acid catalyst continuously to a reaction zone, the reaction zone consists of a cascade of at least two reaction regions connected in series, and the discharge stream of one reaction region forms a feed stream of a downstream reaction region. The cascade may have from two to four reaction regions spatially separated from one another.

A process for the preparation of C.sub.1 -C.sub.4 -alkyl esters of (meth)acrylic acid from esters of the formula I ##STR1## and in case from esters of the formula (II) ##STR2## where R.sup.1 is hydrogen or --CH.sub.3,

Preparation of alkyl esters of (meth)acrylic acid

The continuous esterification of a C.sub.1 -C.sub.8 -alkanol with (meth)acrylic acid in a molar ratio of from 1:1 to 2:1 in the presence of proton-donating catalysts in a homogeneous, liquid, solvent-free phase, in which the water of reaction and resulting alkyl (meth)acrylate are separated off continuously as part of an aqueous azeotropic mixture via the top of a rectification zone attached to the reaction zone, at a top pressure of from 0.1 to 1 atm, and worked up to give pure (meth)acrylate, is carried out by a process wherein the reaction temperature is from 100.degree. to 150.degree. C., the residence time is from 1 to 5 hours and from 5 to 20% by weight, based on the amount of reaction mixture, of sulfuric acid or an equimolar amount, based on such an amount of sulfuric acid, of an organic sulfonic acid is added as a protic acid catalyst to the reaction mixture present in the reaction zone.

Cesium based multimetal oxide compositions which are suitable as catalysts for the gas-phase-catalytic oxidative preparation of methacrolein from isobutene or tert-butanol or its methyl ether. The catalysts are characterized by increased selectivity for the formation of methacrolein. The catalysts have locally delimited regions of an oxide composition, preferably (Bi.sub.2 W.sub.2 O.sub.9), surrounded by the remaining constituents of the multimetal oxide.

Cesium containing multimetal oxide catalyst compositions for the

A process for the preparation of lactates by fermentation of mixtures containing sugars, conversion of the lactic acid obtained during fermentation to its salts, followed by esterification, in which

Preparation of lactates

Methacrolein is removed from a gaseous mixture by absorption by means of an aqueous solution which contains from 60 to 90% by weight of methacrylic acid.

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Waldsee, Germany

Herbert Exner