Bayer Aktiengesellschaft

Michael Holzbrecher

Norbert Lui

Dietmar Bielefeldt

Reinhold M Klipper

Alfred Mitschker

Otto Neuner

Georg Martin

Holger L&uuml;tjens

Andreas Schulze Tilling

Andreas Gr&ouml;schl

Rolf Bunnenberg

The present invention relates to a process for preparing gel-like anion exchangers by aminating crosslinked gel-like styrene divinybenzene bead polymers that contain halogenoalkyl groups in the presence of an inorganic salt and in the absence of organic solvents.

Method for producing osmotically and mechanically stable gel-like anion exchangers

2,3,4,5-tetrafluorobenzene derivatives can be obtained in a particularly advantageous manner by reacting the corresponding chlorobenzene or (chloro, fluoro)-benzene derivatives with a fluorinating agent in the presence of a solvent and a catalyst at elevated temperature, which comprises carrying out the reaction initially under temperature and pressure conditions such that the respective 2,3,4,5-tetrafluoro-benzene derivative continuously distills off through a column, and subsequently setting temperature and pressure conditions such that residual fractions of the 2,3,4,5-tetrafluorobenzene derivative distill off with the corresponding 2,3,4-trifluoro-5-chloro compound.

Process for the preparation of 2,3,4,5-tetrafluorobenzene derivatives

The invention relates to a process for the preparation of diaminodicyclohexylmethane (&ldquo;PACM&rdquo;) with a proportion of trans,trans-4,4&prime;-diaminodicyclohexylmethane of from 17 to 24% by hydrogenation of diaminodiphenylmethane (&ldquo;MDA&rdquo;) in the presence of a pulverulent catalyst in a continuously operated suspension reactor at a conversion of MDA of at least 95%, based on the amount of MDA used.

Continuous process for the preparation of diaminodicyclohexylmethane

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Engelskirchen, Germany

Michael Holzbrecher