Evonik Rohm Gmbh

Evonik Roehm Gmbh

Roehm Gmbh & Co Kg

Horst Hiltner

Hermann Siegert

Udo Gropp

Gerhard Koelbl

Dirk Broell

Jochen Ackermann

Ruediger Carloff

Lorenza Sartorelli

Dirk Bröll

Zhengfeng Zhang

Huisheng Wang

Mirko Michel

Thomas Krauss

Jochen Ackerman

Hans-Rolf Rausch

Ingrid Lunt-Rieg

This invention relates to a process of preparing highly pure, non-yellowing (meth)acrylic acid necessary for high-tech applications requiring long-tem color stability in the presence of amines. Process for the preparation of highly pure, non-yellowing (meth)acrylic acid comprising the steps: f) Condensation of a (meth)acrylic acid-containing gas phase obtained via a gas phase oxidation process of a C4-compound to generate an aqueous (meth)acrylic acid solution g) Separation of the (meth)acrylic acid from the aqueous (meth)acrylic acid solution to obtain crude (meth)acrylic acid h) Rectification of the crude (meth)acrylic acid to obtain pure (meth)acrylic acid via a sidestream outlet of the rectification column i) Treatment of the pure (meth)acrylic acid generated in step c) with an ion exchange resin j) Distillation of the (meth)acrylic acid generated in step d).

Process for preparation of highly pure, non-yellowing methacrylic acid

The present invention relates to a process for preparing methacrylic acid based on the hydrolysis of methacrylic esters.

Process for preparing methacrylic acid

The invention relates to an improved method for the continuous production of alkyl(methyl)acrylates by transesterification of methyl(meth)acrylate with alcohols that are heavy in comparison with methanol. A special processing technique makes it possible to obtain new levels of product quality. Very high space-time-overall yields can also be obtained. The invention is characterized by the multiple use of a homogeneous catalyst which thereby reduces the costs of auxiliary agents significantly.

Method for the continuous production of alkyl(meth)acrylates with multiple catalyst recycling

The invention relates to a process for continuous preparation of alkyl (meth)acrylates by transesterification of methyl (meth)acrylate using alcohols which are high-boiling relative to methanol. A particular workup technique achieves product qualities which have hitherto not been attained. Very high space-time and overall yields can also be achieved.

Method for the continuous production of alkyl (meth)acrylates

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Muenster, Germany

Horst Hiltner