Basf Aktiengesellschaft

Gerhard Laqua

Franz Merger

Tom Witzel

Bernd Bruchmann

Klaus Joachim Mueller-Engel

Stefan Wolff

Andreas Otterbach

Rainer Becker

Ulrich Hammon

Martin Dieterle

Ulrike Wegerle

Peter Pfab

Herbert Helfert

Joachim Pfeffinger

Klaus Mundinger

Ulrich Cremer

Martin Schmidt-Radde

Andreas Johann Schmidt

Hans Volkmar Schwarz

David Agar

Stephan Scholl

Christoph Übler

Volker Krase

Ulrich Eiden

Peter Brandt

Ursula Siebenhaar

Matthias Kl&ouml;tzer

Ulrich Schoner

Konrad Stiefenhofer

A process for the long-term operation of a heterogeneously catalyzed gas phase partial oxidation of at least one organic compound over a catalyst bed, in which, in order to counteract the deactivation of the catalyst bed, the working pressure in the gas phase is increased during the operating time of the catalyst bed.

Long-term operation of a heterogeneously catalyzed gas phase partial oxidation of at least one organic compound

A process for heterogeneously catalyzed gas phase partial oxidation of an organic starting compound over a fixed catalyst bed freshly installed into a reaction chamber, in which the reduction in the quality of the fixed catalyst bed is restored with increasing operating time by replacing a portion of the fixed catalyst bed by a replacement fixed catalyst bed part whose volume-specific activity is lower than the volume-specific activity of the replaced fixed catalyst bed part in its freshly installed state.

Process for heterogeneously catalyzed gas phase partial oxidation of at least one organic starting compound

A process for working up residues from the preparation of pyrrolidone and/or N-vinylpyrrolidone comprises subjecting the residues to a thermolysis.

Method for processing pyrollidone and n-vinyl pyrollidone residues

The present invention relates to a process for the dissociation of allophanates, in which a thermal dissociation is carried out in a reaction vessel and the gaseous dissociation products obtained are removed from the reaction vessel using an inert carrier gas or the vapor of a liquid as stripping medium and are condensed.

Thermal dissociation of allophanates

Organic diurethanes and/or polyurethanes are prepared by reacting organic diamines and/or polyamines (a) with urea and/or alkyl cabamates (b) and alcohols (c) in the presence of soluble zirconium compounds, preferably zirconium alkoxides, zirconium acetate or zirconium acetylacetonate, as catalyst (d). They can be used for preparing diisocyanates and/or polyisocyanates by thermal dissociation.

Method of producing organic diurethanes and/or polyurethanes and their use in the production of di and/or polyisocyanates

Stable (cyclo)aliphatic polyisocyanate compositions obtainable by phosgene-free methods, preferably by thermal cleavage of (cyclo)aliphatic polycarbamates, are stabilized with carbon dioxide, advantageously in an amount of up to 0.3% by weight.

Stable polyisocyanate copositions obtainable by phosgene-free methods

(Cyclo)aliphatic polyisocyanate compositions which have a long shelf life, are obtainable by phosgene-free methods, preferably by thermal cleavage of (cyclo)aliphatic polycarbamates, and, for stabilization, contain at least one primary stabilizer (2a), preferably a sterically hindered phenol and/or an aromatic amine, or at least one secondary stabilizer (2b), preferably an organic phosphite and/or a thioether, or at least one acidic stabilizer (2c), preferably a carboxylic acid, an acyl chloride, an inorganic acid, an inorganic acid chloride and/or a diester of phosphoric acid, or a stabilizer system comprising at least 2 of the stabilizers (2a) to (2c), a process for the preparation of the (cyclo)aliphatic polyisocyanate compositions and their preferred use for the preparation of isocyanurate-containing polyisocyanates.

Polyisocyanate compositions having a long shelf life and obtainable by

A process for the preparation of 3-cyano-3,5,5-trimethylcyclohexanone by the reaction of isophorone with hydrogen cyanide in the presence of quaternary ammonium catalysts at temperatures ranging from 80.degree. to 180.degree. C. and pressures ranging from 0.5 to 20 bar, in which the ammonium catalysts used are salts of the general formula I ##STR1## in which R.sup.1, R.sup.2, R.sup.3, R.sup.4 denote C.sub.1 -C.sub.18 alkyl, C.sub.5 -C.sub.8 cycloalkyl, aryl, C.sub.7 -C.sub.18 aralkyl or C.sub.2 -C.sub.18 hydroxyalkyl and

Preparaion of 3.cyano-3,5,5-trimethylcyclohexanone

Polyisocyanates containing isocyanurate groups are prepared by a partial trimerization of (cyclo)aliphatic diisocyanates in the presence of at least one trimerization catalyst selected from the group consisting of tetraalkylammonium alkyl carbonates of the formula (I) ##STR1## (quaternary ammonioalkyl) carbonates having a betaine structure of the formula (II) ##STR2## and the preferred use of the polyisocyanates containing isocyanurate groups which are obtainable in this way is aspolyisocyanate component in polyurethane finishes.

Preparation of polyisocyanates containing isocyanurate groups and use

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Kapellen, Belgium

Gerhard Laqua