Bayer Materialscience Ag

Lanxess Deutschland Gmbh

Ludwig Deibele

Jan Thomas Leu

Paul Wagner

Manfred Dietrich

Michael Brockelt

Dieter Heinz

Johannes-Peter Schäfer

Wolfgang Scheinert

Guido Naberfeld

Ralf Dohrn

Kai Fahrenkamp

Markus Hadley

Thomas Schilling

The invention provides a process for the purification of polymer polyols that ensures a reduction of acrylonitrile, styrene as well as the residual amounts of optionally used chain regulator, and of occurring recombination products of the initiator when azo initiators are used, to levels of &#x3c;25 ppm of acrylonitrile, &#x3c;50 ppm styrene, &#x3c;50 ppm chain regulator and &#x3c;280 ppm of recombination products by stripping using packed columns.

Process for stripping polymer polyols

The invention relates to a semibatchwise process for the mild distillative separation of mixtures, in a first stage a column being supplied continuously with a feed and the feed being separated at least into different fractions, one of the fractions being removed continuously into a container, and, in a second step, the fraction removed into the container being recycled to the column and being separated again batchwise into different fractions.

Process for the mild distillative separation of mixtures

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Münich, Germany

Ludwig Deibele