Bayer Aktiengesellschaft

Lutz Frohn

Reinhard Langer

Gerhard Darsow

Eberhard Zirngiebl

Jorg-Dietrich Jentsch

Alexander Klausener

Stefan Antons

Erich Wolters

Herbert Diehl

Guido Giffels

Georg Martin

Erich Hammerschmidt

Andreas Schulze Tilling

Frank Arndt

Christoph Tiburtius

Bernd Pennemann

Hanspeter Baumgartner

J&ouml;rg-Dietrich Jentsch

Piperidines are prepared in an advantageous manner by catalytic hydrogenation of activated pyridines in the presence of palladium catalysts if the palladium catalyst is palladium-on-carbon and the solvents are aromatic hydrocarbons.

Process for preparing piperidines

Method for producing catalysts containing ruthenium and the use thereof for hydrogenation

N-phenyl-1-naphthylamine can be prepared by reacting aniline and 1-naphthylamine in the liquid phase at 100-400.degree. C. at a reaction pressure which is higher than atmospheric pressure. Boron and fluorine-containing catalysts, mono or polysulfonic acids, iodine, PCl.sub.3, PCl.sub.5, or POCl.sub.3, for example, may be used as catalysts.

Preparation of N-phenyl-1-naphthylamine

2-Pyrrolidones can be prepared by simultaneous reaction of maleic acid, ammonia or a primary amine and hydrogen at elevated temperature and elevated pressure in the liquid phase over a supported catalyst, with the supported catalyst containing both palladium and rhenium in metallic or bound form.

Process for preparing 2-pyrrolidones

Hydroxymethylcyclopropane is prepared from alkyl cyclopropanecarboxylates by reduction with hydrogen in a process in which use is made of a reduced pelletized catalyst which is obtainable by pressing a mixture of pulverulent copper, zinc and aluminum oxides and subsequent reduction. This process has the advantage that it uses a low-toxicity catalyst which has a long operating life and is particularly suitable for a continuous process and requires relatively low reaction temperatures.

Process for preparing hydroxymethylcyclopropane

Hydroxymethyl-cyclopropane (cyclopropyl-methanol) can be obtained in a manner which is both economical and environment-friendly by catalytic hydrogenation of cyclopropanecarboxylic acid alkyl esters under increased pressure at elevated temperature if a chromium-free zinc oxide catalyst is employed as the catalyst.

Process for the preparation of hydroxymethyl-cyclopropane

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Erkrath, Germany

Lutz Frohn