Basf Aktiengesellschaft

Uwe Vagt

Rolf Hartmuth Fischer

Franz Merger

Claus-Ulrich Priester

Hans-Martin Hutmacher

Wolfgang Harder

Heinz-Walter Schneider

Rudolf Kummer

Franz J Broecker

Wolfgang Richter

Rainer Becker

Wolfgang Hoelderich

Toni Dockner

Hugo Fuchs

Matthias Schwarzmann

Werner Bertleff

Gerald Neubauer

Josef Ritz

Wolfgang Spiegler

Walter Seufert

Michael Roeper

Wolfgang Franzischka

Manfred Sauerwald

Heinz Eckhardt

Juergen Frank

Martin Decker

David Agar

Fritz Naeumann

5-Methylbutyrolactone is prepared by a process in which a pentenoic ester of the formula I

Preparation of 5-methylbutyrolactone

6-Aminocaproic esters are prepared by reacting alkyl 5-formylvalerates with excess ammonia and hydrogen in the presence of ruthenium catalysts at elevated temperature under superatmospheric pressure in liquid ammonia as reaction medium.

Preparation of 6-aminocaproic esters

Caprolactone is prepared by a process in which a 6-hydroxycaproic ester in vapor form is passed, together with an inert carrier gas, at from 150.degree. to 450.degree. C., over a fixed-bed or fluidized-bed oxidic catalyst.

Preparation of caprolactone

Caprolactam is purified continuously by passing a 75-95% strength by weight aqueous caprolactam solution together with hydrogen at 50.degree.-95.degree. C. and 1.5-100 bar upward through a fixed-bed supported palladium or nickel catalyst in a tubular zone while maintaining a residence time of from 10 to 100 min.

Continuous purification of caprolactam

Caprolactam is prepared in a process comprising the following steps:

Preparation of caprolactam

Preparation of 6-aminocaproic acid

2(5H)-furanones I ##STR1## where R.sup.1 and R.sup.2 are each hydrogen, C.sub.1 -C.sub.6 -alkyl, C.sub.5 - or C.sub.6 -cycloalkyl, C.sub.7 -C.sub.12 -aralkyl or aryl, are prepared by heating a 3-formylcarboxylate or 3-formylcarboxylic acid II ##STR2## where R.sup.3 is hydrogen, C.sub.1 -C.sub.12 -alkyl, C.sub.5 - or C.sub.6 -cycloalkyl, C.sub.7 -C.sub.12 -aralkyl or aryl, to 100.degree.-450.degree. C. in the presence of an acidic catalyst.

Preparation of 2(5H)-furanones

A process for the preparation of esters of tetrahydropyran-4-carboxylic acid of the general formula I, where R.sup.1 is an alkyl, cycloalkyl, or aryl group, by treating butyrolactones of the general formula II, where R.sup.2 is a hydrogen atom, an alkyl group, or an acyl group --CO--R.sup.3, R.sup.3 being a hydrogen atom or an alkyl group with from 1 to 6 carbon atoms, with alcohols of the general formula III at temperatures of from 150.degree. C. to 400.degree. C. in the presence of acid catalysts. ##STR1##

Preparation of esters of tetrahydropyran-4-carboxylic acid

Alkenecarboxylates of the formula I ##STR1## where R.sub.1 is alkyl of 1 to 6 carbon atoms and n is 2, 3 or 4, are prepared by a process which comprises reacting a lactone of the formula II ##STR2## where R.sub.2 is hydrogen or methyl and m is 1 or 2, with an alkanol of 1 to 6 carbon atoms in the presence of an acidic catalyst at from 150.degree. to 400.degree. C.

Preparation of alkenecarboxylates

In an improved process for preparing caprolactam by heating 6-aminocaproic acid, an ester or amide or mixture thereof in the presence of an inert reaction medium which is liquid under the reaction conditions and has a boiling point above that of caprolactam, the improvement comprises using as the reaction medium a hydrocarbon, maintaining a temperature of from 150.degree. to 350.degree. C., charging the 6-aminocaproic acid, ester, amide or mixture thereof at a rate commensurate with their rate of conversion, and separating caprolactam from the reaction mixture at a rate commensurate with its rate of formation.

Preparation of caprolactam from 6-aminocaproic acid, esters and amides

In an improved process for the preparation of 6-aminocaproates by reacting a 5-formylvalerate with ammonia and hydrogen using an alkanol as a solvent in the presence of a hydrogenation catalyst at elevated temperatures and under superatmospheric pressure, the improvement comprises carrying out the reaction at from 40.degree. to 95.degree. C.

Preparation of 6-aminocaproates

Cyclic ketones of the formula ##STR1## where n is an integer from 4 to 6, are prepared by converting an aliphatic dicarboxylate of the formula

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Speyer, Germany

Uwe Vagt