Bayer Aktiengesellschaft

Bayer Materialscience Ag

Bayer Intellectual Property Gmbh

Ralf Dohrn

Manfred Dietrich

Michael Brockelt

Christoph Braden

Jan Thomas Leu

Guido Naberfeld

Ludwig Deibele

Markus Hadley

Thomas Jan Leu

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 chemical reactor is based on a cylindrical vessel with a stirring device. The stirring device consists of a magnetic stirrer 3, 5, 11a, 11b, 12 with magnetic coils which are disposed around the outside of the cylindrical vessel 1 in the form of a star and produce a magnetic field and of a rotor 3 which is mounted in the region of the rotating field in the vessel 1 such that it can rotate about the cylinder axis. The rotor is provided with stirring blades 11a, 11b, 12 and comprises permanent magnets 5 co-operating with the rotating field.

Chemical reactor with magnetic stirring device

Growing community of inventors

Bergisch Gladbach, Germany

Ralf Dohrn