Bayer Aktiengesellschaft

Miles Inc.

Franz-Moritz Richter

Hanns P Muller

Jan Mazanek

Walter Schafer

Berthold Keggenhoff

Wolfgang Oberkirch

Gunther Ellendt

Marcel Petinaux

Christian Konig

Manfred L Gallus

Rudolf Uchdorf

Roland Nast

Reinhold Wullner

William C Forester

A process for production of polyamines of the diphenylmethane series through a condensation reaction of aniline with formaldehyde in the presence of an acid catalyst, neutralization of the acid catalyst after reaction completion, and distillation of the resultant polyamine mixture is described. The key feature of the process is the abrupt increase in reaction temperature after the condensation reaction or after the first rearrangement step.

Process for the production of polyamine mixtures of the

Crude polyisocyanates are purified by extraction at a temperature from 80.degree. to 180.degree. C. to form a two-phase system. The phases are separated and the phase made up of purified polyisocyanate and solvent is cooled to a temperature which is at least 50.degree. C. below the extraction temperature. Upon cooling, a second two-phase system forms. Purified polyisocyanate containing residual solvent is recovered upon separation of these phases. Solvent in which polyisocyanate is present that is reclaimed during this process may be reused in subsequent extractions. The purified polyisocyanates have a viscosity which is lower than that of crude polyisocyanates having substantially the same isocyanate content and average functionality. These purified polyisocyanates are useful in the production of polyurethane foams and moldings as well as adhesives and coatings.

Process for purifying polyisocyanates and the polyisocyanates thus

New alkoxylated aminopolyethers of the formula ##STR1## in which Q denotes a polyalkylene oxide radical which has a valency corresponding to n, which has a structure derived from an aminopolyether by removal of the terminal amino groups and which has an average molecular weight of 82 to 30,000,

Alkoxylated aminopolyethers, a process for their preparation

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Dormagen, Germany

Franz-Moritz Richter