Bayer Aktiengesellschaft

Bayer Materialscience Ag

Studiengesellschaft Kohle Mbh

Covestro Deutschland Ag

Daniel Koch

Torsten Hagen

Stefan Wershofen

Walter Leitner

Hans-Georg Pirkl

Rudolf Uchdorf

Gerhard Wegener

Richard Adamson

Friedhelm K&auml;mper

Heinz-Herbert M&uuml;ller

Klaus Langemann

Dietmar Wastian

Stephan Klein

Christine Mendoza-Frohn

Fritz Pohl

Karl-Heinz Köhler

Stephan Konrad

Heinrich Hähnsen

Marc Buts

Stefan Grabowski

Giancarlo Francio

Spotswood Miller

Christian Six

Alois F&uuml;rstner

Ricardo Serra

Jürgen Kirsch

Dirk Grotjohann

Sabine Kainz

Frank Guldentops

The invention relates to a polycarbonate composition having reduced subsequent yellowing of the mouldings produced therefrom on heat ageing and having good optical properties of the polycarbonate composition on processing.

Polycarbonate composition having improved heat stability

A two-stage process for the preparation of organic isocyanates by reacting primary amines with phosgene in which: a) in a first stage, amine and phosgene are reacted in an adiabatically managed reaction, in which the temperature of reaction is restricted to values between 100 and 220&#xb0; C. by actively adjusting the absolute pressure in the reactor to values between 8 and 50 bar by decompression, and the temperature is held at values between 100 and 220&#xb0; C. until the stoichiometric conversion of phosgene has reached at least 80%; and then b) in a second stage, the reaction mixture from a) is decompressed to an absolute pressure of 1 to 15 bar and the reaction mixture is reacted further at temperatures between 90 and 240&#xb0; C., optionally with the introduction of heat.

Process for preparing polyisocyanates by the adiabatic phosgenation of primary amines

The invention provides a process for the preparation of polyamines of the diphenylmethane series. This process comprises

Process for the preparation of polyamines of the diphenylmethane series at a low degree of protonation

Di- and polyamines of the diphenylmethane series are prepared by a) mixing a first portion of aniline with an acid catalyst, b) mixing a second portion of aniline with formaldehyde, and c) mixing and reacting the mixtures prepared in each of steps a) and b). The diamines produced by this process may then be phosgenated to produce the corresponding di-/polyisocyanate.

Process for the preparation of di- and polyamines of the diphenylmethane series

The invention relates to a method of producing polyisocyanates of the diphenylmethane series including the steps of

Process for the production of polyisocyanates of the diphenylmethane series by phosgenation of non-neutralized polyamine of the diphenylmethane series

Polyisocyanates of the diphenylmethane series are produced by a) reacting aniline and formaldehyde in the presence of an acidic catalyst to produce a polyamine, b) neutralizing the reaction mixture from step a) with a base at a temperature of more than 110&deg; C. or neutralizing the reaction mixture from step a) with a base and heating the neutralized mixture to a temperature of more than 110&deg; C., and c) phosgenating the polyamine from step b) to convert it to the corresponding polyisocyanate.

Process for the production of polyisocyanates of the diphenylmethane series with a reduced color value

The present invention concerns a process for the production of methylenedianiline (MDA) having a high monomer content.

Method for production of diaminodiphenylmethanes

Polyisocyanates of the diphenyl methane series having reduced color values are obtained by a) reacting aniline and formaldehyde in the presence of an acid catalyst to form a polyamine, b) neutralizing the reaction mixture containing polyamine with a base, c) separating the neutralized mixture into the aqueous and the organic phases, d) adding a base to the organic phase and then e) phosgenating the resulting polyamine to produce the corresponding polyisocyanate.

Process for producing polyisocyanates of the diphenyl methane series having a reduced color value

Methods for producing chiral aldehydes

The present invention relates to processes for the preparation of oxo products by the hydroformylation of substrates having C&boxH;C double bonds using unmodified rhodium catalysts in a reaction mixture essentially consisting of the substrates, the catalyst and carbon dioxide in a supercritical state (scCO ). In particular, the invention relates to such processes for the preparation of products which contain substantial proportions of branched i-oxo products. Further, the invention relates to such processes for the hydroformylation of substrates which do not correspond to the general formula C H . The invention further relates to such processes in which the separation of product and catalyst is effected using the special solvent properties of scCO .

Hydroformylation with unmodified rhodium catalysts in supercritical carbon dioxide

Cyclic products are prepared by selective olefin metathesis of bifunctional or polyfunctional substrates in the presence of one or several homogeneous or heterogeneous metathesis catalysts in a reaction medium. The invention is characterized in that the substrates contain two or more functional groups in the form of substituted or non-substituted alkene or alkyne units and in that the reaction medium essentially consists of compressed carbon dioxide. Also disclosed is the preparation of cyclic or polymer products according to the disclosed process, the reaction temperature and total pressure being matched to ensure that the density of the reaction medium lies in a range d&equals;0.2-1.5 g&middot;cm and that the product distribution is essentially controlled by the reaction medium density.

Selective olefin metathesis of bifunctional or polyfunctional substrates in compressed carbon dioxide as reaction medium

Growing community of inventors

Duisburg, Germany

Daniel Koch