Evonik Degussa Gmbh

Jan Caßens

Stephan Kohlstruk

Axel Hengstermann

Anne Rittsteiger

Alexander Martin Rüfer

Jörg-Joachim Nitz

Robert Jansen

Cord Knoop

Andreas Merkel

Stephanie Bajus

Jens Döring

Anja Müller

The present invention is directed to a process for fine purification of isophoronediamine from the production of isophoronediamine wherein the crude isophoronediamine I is subjected to a fine purification by means of two vacuum distillation columns, wherein I. in the first vacuum distillation column K I low-boiling by-products still present are removed, and a crude IPDA II is transferred from the bottom of K I into the vacuum distillation column K II, II. and in the second vacuum distillation column K II the isophoronediamine is obtained in pure form overhead and separated from the organic residues, wherein the first condenser is a partial condenser and the pure IPDA is removed therein, and wherein the second condenser is a total condenser and the residual portion of the vapor stream from K II is completely condensed therein and recycled as return stream into the first vacuum distillation column K I.

Purification of crude isophoronediamine by partial condensation in series with total condensation

The present invention provides a novel process for producing 2,6,6-trimethyl-2-cyclohexene-1,4-dione (keto-isophorone) by catalytic oxidation of 3,5,5-trimethylcyclohexa-3-ene-1-one (&#x3b2;-isophorone) with hydrogen peroxide as the oxidant. In particular, the novel process includes phase transfer reagent in a biphasic system including an organic phase and an aqueous phase wherein the biphasic system includes 1) a tungsten polyoxyometallate as catalyst and hydrogen peroxide, and/or 2) a mixture of a) a mineral acid, b) hydrogen peroxide, and c) a metal tungstate.

Catalytic oxidation of 3,5,5-trimethylcyclohexa-3-ene-1-one (&#x3b2;-isophorone) with hydrogen peroxide to afford 2,6,6-trimethyl-2-cyclohexene-1,4-dione (keto-isophorone)

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Recklinghausen, Germany

Jan Caßens