Basf Aktiengesellschaft

Peter Wahl

Hermann Luyken

Boris Breitscheidel

Tom Witzel

Guido Voit

Karl-Heinz Ross

Joachim Simon

Rolf Pinkos

Michael Hesse

Wolfgang Harder

Karsten Eller

Peter Pfab

Joachim Wulff-Doring

Axel Paul

Willi Schmidt

Dieter Franz

In a process for purifying crude pyrrolidine to give a pyrrolidine composition comprising more than 99% (m/m) of pyrrolidine and less than 0.3% (m/m) of water, crude pyrrolidine comprising from 40 to 98% (m/m) of pyrrolidine and having a water content of more than 2% (m/m) is subjected to continuous distillation at a pressure at the top of less than 950 hPa in a column having a stripping section and a rectifying section.

Dewatering and purification of crude pyrrolidine

Hydrogenation of aldehydes

A process for preparing pyrroles of the formula I: ##STR1## where R.sub.1, R.sup.2, R.sup.3 and R.sup.4 are identical or different and are hydrogen atoms, alkyl groups having from 1 to 12 carbon atoms or cycloalkyl groups having from 3 to 12 carbon atoms, by dehydrogenation of pyrrolidines of the formula II: ##STR2## where R.sup.1, R.sup.2, R.sup.3 and R.sup.4 are as defined above, in the presence of a supported noble metal catalyst is described. In this process, the dehydrogenation is carried out at from 150 to 300.degree. C. and pressures of from 0.01 to 50 bar and the noble metal catalyst comprises from 30 to 100% by weight of:

Preparation of pyrroles

A process for the preparation of 3-aminomethyl-3,5,5-trimethylcyclohexylamine having a cis/trans isomer ratio of at least 70:30 by

Preparation of 3-aminomethyl-3,5,5-trimethylcyclohexylamine having a

A process for the preparation of 3-aminomethyl-3,5,5-trimethylcyclohexylamine from 3-cyano-3,5,5-trimethylcyclohexanone which requires three spatially separated reaction spaces, in order to carry out the following three steps in sequence: a) reacting the 3-cyano-3,5,5-trimethylcyclohexanone with excess ammonia on acidic metal-oxide catalysts in a first reaction space at from 20.degree. to 150.degree. C. and from 50 to 300 bar, b) hydrogenating the resultant reaction products using hydrogen in a second reaction space in the presence of excess ammonia and preferably liquid ammonia on hydrogenation catalysts, optionally using basic components or on neutral or basic supports at from 50.degree. to 100.degree. C. and at from 50 to 300 bar, and c) hydrogenating the resultant reaction products in the presence of hydrogen and also ammonia in a third reaction space on hydrogenation catalysts, optionally using basic components or on neutral or basic supports at from 110.degree. to 160.degree. C. and at from 150 to 300 bar. These three steps in sequence provide a substantially complete reaction of the original 3-cyano-3,3,5-trimethylcyclohexanone reactant with a yield of 96% of the desired diamino product in which the cis-content of the diamine is 70%.

Preparation of 3-aminomethyl-3,5,5-trimethylcyclohexylamine

A process for purifying crude pyrroles obtained in the preparation of pyrroles of the general formula I ##STR1## where R is hydrogen or a C.sub.1 -C.sub.6 -alkyl radical, which comprises treating the mixture containing the crude pyrrole with an acid or an activated carboxylic acid derivative and removing the pyrrole from the mixture by distillation at reduced pressure and at a bottom temperature of up to 160.degree. C.

Purification of crude pyrroles

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Peter Wahl