Basf Aktiengesellschaft

Basfaktiengesellschaft

Gerhard Nestler

Franz Merger

Heinrich Aichinger

Holger Herbst

J&uuml;rgen Schr&ouml;der

Toni Dockner

Michael Fried

Ulrich Hammon

Albrecht Dams

Friedrich Towae

Hans Martan

Helmut Lermer

Alexander Weck

Jürgen Schröder

Herbert Exner

Ulrich Rauh

Matthias Geisendorfer

Jerry Darlington

Klaus Joachim Mueller-Engel

Andreas Deckers

Guenter Hansen

Juergen Schroeder

Georg Zeidler

Norbert Guentherberg

Siegmund Besecke

Gabriele Iffland

Karl-Heinz Wassmer

Martin Brudermueller

Rolf Henn

Willi Schmidt

Ruprecht Kroker

Klaus Joachim M&uuml;ller-Engel

Hans Hellbach

Paul Leon Kageler

Reinhard Herzog

Werner Schmitt

Peter Ruckh

Winfried Schumm

Matthias Geisendoerfer

Knut Oppenlaender

Wolfgang Harder

Otto Machhammer

Heinz Eilingsfeld

Oral Aydin

Eberhard Fuchs

Gerd Rehmer

Klaus Joachim Müller-Engel

Rolf Platz

Bernd Eck

Andreas Boettcher

Stefan Beckmann

Wolfgang Schwarz

Joachim Thiel

Uwe Kempe

Max Strohmeyer

Heinz Hohenschutz

Friedrich-Georg Martin

Herbert Vogel

Hans-Martin Hutmacher

Rudolf Mueller-Mall

Guenter Uhl

Ernest Miesen

Gerhard Sandrock

Peter Pfoehler

Stefan Wickel

Klaus Bittins

Gerhard Bolz

Hugues Vandenmersch

Oliver Odenwald

Maria G Szucsanyi

Gundo Brauch

Ruediger Wissler

Lawrence Edwin James

Gerhard Dietrich

Ludwig Schroff

Theodor Jacobsen

Nicole McGlone

Manfred Lazarus

Klaus Lehnert

This invention relates to a process for preparing a low-odor hydrogel-forming acrylic acid polymer, which comprises the steps of: a) preparing a polymeric hydrogel by free-radically polymerizing a monomer composition comprising at least 50% by weight of acrylic acid in an aqueous polymerization medium and converting said hydrogel into a particulate hydrogel or into hydrogel-forming powder; and optionally b) treating said particulate hydrogel or said hydrogel-forming powder with a crosslinking substance which, actually or latently, contain at least two functional groups capable of reacting with the carboxyl groups on the addition polymer; characterized by the acrylic acid used in step a) containing less than 400 ppm of acetic acid and propionic acid. It further relates to the hydrogel-forming addition polymers obtainable by the process and to their use.

Method for producing low-odor hydrogel-forming polymers

Basic (meth)acrylates IV are prepared by transesterification of alkyl (meth)acrylates I in the presence of a catalyst and working-up of the reaction mixture by distillation, by a process in which a gas or gas mixture which is inert under the reaction conditions is passed through the reaction zone and/or heat exchanger.

Method for producing (meth)acrylic acid esters

The invention relates to a method for producing (meth)acrylic acid esters IV by means of transesterification of a (meth)acrylic acid ester I with an alcohol ROH comprising at least one more carbon atom than the alcohol constituents (RO&#x2014;) in the (meth)acrylic acid ester I to be subjected to transesterification, in the presence of a catalyst or a catalyst mixture. Either essentially the (meth)acrylic acid ester I is separated and then the catalyst used is separated by distillation (catalyst separation), or the catalyst used is separated by distillation first (catalyst separation), and then essentially the (meth)acrylic acid ester I is separated, from the reaction product of the transesterification. Constituents from the mixture obtained, which have a lower boiling point than the (meth)acrylic acid ester IV, are essentially separated by distillation (separation of constituents at low boiling point), and the (meth)acrylic acid ester IV is then purified by distillation (purification by distillation).

Method for producing (meth) acrylic acid esters

Acrylic acid is prepared from propene by means of gas-phase oxidation by a process in which a starting gas mixture which contains propene and steam and whose molar propene/steam ratio is &#x2267;1 and whose propane content is &#x2266;5% is passed at elevated temperatures through a fixed catalyst bed comprising successive catalyst part-beds A and B, the part-bed A passed through first containing, as active material, a mixed oxide containing the elements Mo, Bi and Fe and the part-bed B containing, as active material, a mixed oxide containing the elements Mo and V, in a manner such that at least 96.5 mol % of propene are converted in a single pass through part-bed A.

Method for the production of acrylic acid by heterogeneously-catalysed gas-phase oxidation

In a process for preparing water-absorbent resins based on acrylic acid, crude acrylic acid is firstly isolated from the reaction gases from the catalytic gas-phase oxidation of propane, propylene and/or acrolein. This is treated with an aldehyde scavenger and pure acrylic acid is separated by distillation from the treated crude acrylic acid, and this pure acrylic acid can be subjected directly to a free-radical polymerization.

Method for producing water-absorbent resins

Higher (meth)acrylates IV are prepared by transesterification of a lower (meth)acrylate I with a higher alcohol ROH in the presence of a stabilizer or stabilizer mixture and of a catalyst or catalyst mixture, by a process in which the liberated lower alkanol ROH is separated off and is fed at least partly to the preparation of the lower (meth)acrylate I.

A tert-C&#x2013;C-alkyl (meth)acrylate is prepared by reacting (meth)acrylic acid with an olefin of the formulawhere The novel process makes it possible to use acetic acid-containing (meth)acrylic acid. The danger of cleavage of the ester and of polymerization of (meth)acrylic compounds is reduced.

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In a process for preparing an ester of an unsaturated carboxylic acid by reacting an ester of the unsaturated carboxylic acid and a C-C-alkanol with an alcohol ROH, where Ris a C-C-alkyl radical, a C-C-cycloalkyl radical, a phenyl-C-C-alkyl radical or a C-C-alkyl radical substituted by at least one NRRgroup or by from 1 to 3 hydroxyl groups or C-C-alkoxyl groups or interrupted by one or more oxygen atoms, where the radicals Rare, independently of one another, C-C-alkyl or together with the nitrogen atom form a 5- to 7-membered heterocyclic ring which may contain a further nitrogen or oxygen atom, in the presence of a transesterification catalyst, the transesterification catalyst used is at least one metal alkanolate containing at least one ORgroup, where Ris a 2,2,6,6-tetraalkyl-1-oxylpiperidin-4-yl radical.

Method for the production of esters of unsaturated carboxylic acids

Mixtures containing monomers having at least one ethylenically unsaturated group are chemically and/or physically treated in the presence of the reaction products of alkylsuccinic anhydrides and stable N-oxyl radicals having a hydroxyl group.

Treatment of mixtures that contain at least one compound with at least one ethylenically unsaturated group

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

In a process for rectificative isolation of (meth)acrylic acid from a mixture containing, as main components, (meth)acrylic acid and an organic liquid having a higher boiling point than (meth)acrylic acid, the rectification is carried out with the addition of a surfactant.

Rectification of (meth)acrylic acid with the addition of a tenside

Method for producing tert-butyl esters of aliphatic c1-c4-carboxylic acids

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

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Ludwigshafen, Germany

Gerhard Nestler