Huels Aktiengesellschaft

Gerhard Thelen

Stefan Frentzen

Dietrich Maschmeyer

Wilhelm Droste

Heinz-Werner Voges

Udo Jegelka

Guenter Kreilkamp

Gerhard Wachholz

Otto Hallmann

Guthard Mock

Elmhart Neuber

Harald Bartels

Gerhard Bachstaedter

Herbert Deppe

A process for the continuous preparation of 4-amino-2,2,6,6-tetramethylpiperidine (TAD), comprising: passing triacetoneamine, ammonia and hydrogen over a catalyst of at least two layers in a reactor, wherein at least one catalyst layer comprises at least one element of the 4th, 5th, or 6th row of the 8th transition group of the Periodic Table or combinations of these metal elements on a suitable support, where the catalyst content with respect to each individual catalytically active element changes independently from the reactor inlet to the reactor outlet.

Continuous process for the preparation of

A process for preparing 4-amino 2,2,6,6-tetramethylpiperidine (TAD) from 2,2,6,6-tetramethylpiperidone (TAA), ammonia and hydrogen using a cobalt or nickel catalyst on a support which allows the omission of any added solvent, and provides substantially simplified work-up and increased space-time yields by significantly reducing the amounts of excess ammonia and catalyst needed to accomplish the reaction.

Solvent-free process for preparing 4-amino-2,2,6,6-tetramethylpiperidine

A catalyst for preparing bis-para-aminocyclohexylmethane by hydrogenation of methylenedianiline, comprising ruthenium or rhodium in an amount of from 0.05 to 8% by weight, applied in a layer thickness of from 5 to 150 .mu.m to a support comprising a calcined and surface-rehydrated transition alumina, wherein a suspension of 10 g of the transition alumina in 300 ml of water at 25.degree. C. has an equilibrium pH of at least 8.2 after 60 minutes and after addition of 10 ml of 0.1N hydrochloric acid to this suspension it has a pH of at least 6.0 after 30 minutes.

Catalyst for preparing bis-para-aminocyclohexylmethane containing a low

The present invention relates to a process for the preparation of 4-hydroxy-2,2,6,6-tetramethylpiperidine by heterogeneous catalytic hydrogenation of 4-oxo-2,2,6,6-tetramethylpiperidine in a melt or solution at temperatures of 60.degree. C. to 200.degree. C. and hydrogen pressures of 10 to 300 bar, in the presence of a catalyst comprising

Process for the preparation of 4-hydroxy-2,2,6,6-tetramethylpiperidine

Deactivated hydrogenation catalysts of ruthenium metal deposited on an aluminum oxide support are regenerated by treatment with ultrasound.

Ultrasound method of reactivating deactivated hydrogenation catalyts

A process for manufacturing an alkynediol is disclosed. In this process, a C.sub.3-12 ketone is reacted with acetylene in the presence of potassium hydroxide in an C.sub.1-4 alkyl-tert-butyl ether solvent. The potassium hydroxide is used in a molar ratio, relative to the amount of ketone used, of from 1.0:1.0 to 1.6:1.0.

Process for the manufacture of alkynediols by reaction of ketones with

Vinyl chloride is prepared by reacting acetylene with hydrogen chloride in the presence of a palladium compound catalyst in a solvent of an aliphatic and/or cycloaliphatic carboxylic acid amide at temperatures higher than room temperature.

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Nottuln, Germany

Gerhard Thelen