Huels Aktiengesellschaft

Thomas Keil

Manfred Kaufhold

Wolfgang Schroder

Wilhelm Huwels

Georg Doll

Reinhold Gull

Bernd Helpap

The polymerization of a vinylaromatic or vinylaliphatic compound at elevated temperature in the absence of air is inhibited by processing the vinylaromatic or vinylaliphatic compound in the presence of 4-hydroxy-2,2,6,6-tetramethylpiperidine-N-oxyl or 4-acetylamino-2,2,6,6-tetramethylpiperidine-N-oxylalone or in admixture with p-nitrosophenol or 2-methyl-4-nitrosophenol.

Inhibition of polymerization of vinylaromatic or vinylaliphatic

A process for separating ethylbenzene and styrene by distillation is described. The process provides the advantages of a vapor compression/heat pump system, and is designed in such a manner that the energy applied is optimally utilized. The head pressure of the distillation column (1) is controlled in a simple manner, whereby a surprisingly stable column is achieved.

Process for separating ethylbenzene and styrene by distillation

Cyclohexane derivatives containing carboxyl groups with the general structure of formula (I): ##STR1## alone or in mixtures with one another, in which the substituents on the cyclohexane ring are in the 1-, 2-, and 4-positions, Z is a --CH.sub.2 --CH.sub.2 -- group or a ##STR2## group, R is an alkyl group with 1 to 10 carbon atoms, and n is an integer of 1 to 3, are obtained by the hydrocarboxyalkylation of 1,2,4-trivinylcyclohexane and are useful as monomers for the formation of polymers.

Cyclohexane derivatives containing carboxyl groups

Hydrocarboxyalkylation of .alpha.,.omega.-dienes with carbon monoxide and an alcohol in the presence of a cobalt compound and a tertiary amine gives .omega.-enecarboxylic acid esters with high selectivity and in good yields.

Process for the preparation of .omega.-enecarboxylic acid esters

A method of manufacturing cyclooctanedicarboxylic acid diesters by hydrocarboxyalkylation of 1,5-cyclooctadiene over a cobalt catalyst in the presence of tertiary amines is disclosed.

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Marl, Germany

Thomas Keil