Basf Aktiengesellschaft

Baf Aktiengesellschaft

J&uuml;rgen Schr&ouml;der

Gerhard Nestler

Heinrich Aichinger

Volker Schliephake

Heinz Friedrich Sutoris

Gerhard Wagenblast

Harald Keller

Holger Herbst

Thomas Jaworek

Klaus Joachim M&uuml;ller-Engel

Otto Machhammer

Stefan Beckmann

Joachim Thiel

Knut Kessel

Albrecht Dams

Friedrich-Georg Martin

Konrad Mitulla

J&uuml;rgen Decker

Rainer Rahm

Roland Merger

Gerhard Bolz

Susanne Haupt

Reinhard Herzog

Hermann Uhr

Nicole McGlone

The invention relates to a method for producing (meth)acrylic acid esters by transesterification of the (meth)acrylic acid with a higher alkanol in the presence of an acid catalyst, at least one polymerization inhibitor and one organic solvent that forms an azeotropic mixture with water. The reaction mixture is heated to the boiling point of the mixture in a reactor that comprises a distillation unit with a column and a condenser. The content of the reactor is recirculated via an external evaporator and heated to the boiling point, and the azeotropic mixture is distilled off. The organic solvent forms a reflux and at least a part of the solvent reflux is recirculated between the reactor and the evaporator. The inventive method allows for the production of higher (meth)acrylic acid esters in a reactor with a circulation evaporator without using copper salts as the polymerization inhibitors.

Method for producing higher (meth)acrylic acid esters

Polymerizable compounds are prepared and/or worked up using at least one liquid ring pump by a process in which a working liquid which contains a material stream from the preparation and/or working-up of the polymerizable compound is used in a liquid ring pump.

Preparation of polymerizable compounds

An inhibitor mixture containing, as components, a) at least one nitroxyl radical (derivative), b) at least one phenol (derivative) and c) at least one chemical compound which contains at least one phosphorus atom which has the oxidation state &plus;3 is preferably used for stabilizing compounds capable of free radical polymerization.

Inhibitor composition for stabilizing substances capable of free radical polymerization

Method for producing acrylic acid and acrylic acid esters

In a process for the fractional condensation of an acrylic acid-containing product gas mixture of a gas-phase partial oxidation of C precursors of acrylic acid with molecular oxygen under heterogeneous catalysis, the separation column used contains both dual-flow trays and hydraulically sealed cross-flow trays as baffles having separation activity.

Fractional condensation of a product gas mixture containing acrylic acid

An ester of an &agr;,&bgr;-unsaturated carboxylic acid is prepared by reacting the carboxylic acid with a C -C -alkanol, cyclopentanol or cyclohexanol in the presence of an acidic esterification catalyst and of an entraining agent for removing the water of reaction formed in the esterification, by a process in which the entraining agent used is the olefin on which the alkanol is based.

Method for producing esters of &agr;, &bgr;-unsaturated carboxylic acids

In a process for esterifying (meth)acrylic acid with an alkanol in the presence of an esterification catalyst, in which unconverted starting compounds and (meth)acrylic ester to be formed are separated off by distillation and an oxyester-containing bottom product is formed, the bottom product is first separated off and then the oxyesters contained in it are cleaved in the presence of a relatively long-chain alkylbenzenesulfonic acid at elevated temperatures.

Method for esterifying (meth)acrylic acid with an alkanol

Method of cleaning plant parts for the preparation or processing of (meth)acrylic esters

Method for producing acrylic acid and acrylic acids esters

In a process for stabilizing chemical compounds having at least one ethylenically unsaturated bond to undesired free radical polymerization, a nitroxyl radical and a chemical compound containing phosphorus in chemically bonded form are added to the unsaturated compound present as pure substance or as a component of a mixture.

Method for stabilizing chemical compounds containing at least one ethylenically unsaturated bond in order to prevent undesirable radical polymerization

Free radical polymerizations immediately terminated by a process comprising the addition of an inhibitor solution which contains phenothiazine and at least 50% (w/w) N-alkylpyrrolidone to a system undergoing free radical polymerization, wherein the inhibitor solution also contains p-methoxyphenol (MEHQ).

Method of immediately terminating free-radical polymerisation processes

Preparation of (meth)acrylates

In a process for the preparation of acrylic acid, a product gas mixture obtained by catalytic gas-phase oxidation of a C -precursor of acrylic acid and containing acrylic acid is directly cooled with a quench liquid and then subjected to fractional condensation in a separation column provided with baffles, said product gas mixture ascending into itself and a crude acrylic acid being removed via a side take-off, and the acrylic acid oligomers formed are cleaved and recycled.

Method for producing acrylic acid

An article having a metallic surface treated with polymeric complexing agent is described. Particularly suitable polymeric complexing agents are phosphonoalkylated polyethyleneimines and/or carboxyalkylated polyethyleneimines and/or vinylimidazole polymers. As a rule, the treated metallic surface forms the total inner surface or a part of the inner surface of a process apparatus or of a container. The surface is protected by the treatment, in particular from the adhesion of polymer.

Apparatus having a metallic surface protected from undesired deposition of polymer

Growing community of inventors

Ludwigshafen, Germany

Jürgen Schröder

Growing community of inventors

Ludwigshafen, Germany

J&uuml;rgen Schr&ouml;der

Jürgen Schröder