Basf Aktiengesellschaft

Basf Corporation

Wilfried Seyfert

Peter Stops

Hubert Lendle

Paul Panitz

Bernd Bruchmann

Dietrich Scherzer

Roland Minges

Peter Keller

Wolfgang Heider

Gunter Schuch

Siegmund Pohl

Gerhard Frank

Bernhard Otto

Heinrich Reitz

Willy Van Pee

Paul Jacobs

Mixtures of diphenylmethane diisocyanates and polyphenylpolymethylene polyisocyanates (raw MDI) having a reduced iodine color number and a reduced chlorine content are prepared by reacting the corresponding mixtures of diphenylmethanediamines and polyphenylpolymethylenepolyamines with phosgene in the presence of at least one inert organic solvent at elevated temperature, and then, after phosgenation is complete, incorporating into the reaction mixture, in the presence or absence of the phosgene, a mixture of water and at least one monohydric or polyhydric polyoxyalkylene alcohol, preferably having a functionality of from 2 to 3, and advantageously having a hydroxyl number of from 20 to 1800, in an effective amount which advantageously comprises from more than 0.01 to 0.3% by weight of water (i) and from 0.5 to 5% by weight of a polyoxyalkylene alcohol (ii), in each case based on the weight of raw MDI, then removing the excess phosgene or the phosgene residues still present and the inert organic solvent, if desired adding to the reaction product up to 5% by weight, based on the weight of raw MDI, of at least one antioxidant based on phenol and/or aryl phosphite and thermally treating the reaction mixture.

Preparation of mixtures of diphenylmethane diisocyanates and polyphenylpolymethylene polyisocyanates having a reduced iodine color number and a reduced chlorine content

A process for the continuous preparation of alkyl pentenoates comprises the following steps:

Continuous preparation of alkyl pentenoates

Carboxylic esters obtained by reacting olefinically unsaturated compounds with carbon monoxide and alcohols and containing aldehydes, acetals and/or unsaturated compounds are purified by

Purification of carboxylic esters which contain aldehydes, acetals

Pyridine or methylpyridines or mixtures thereof are recovered from methyl butanedicarboxylate containing reaction mixtures obtained by reaction of methyl pentenoate with carbon monoxide and methanol in the presence of pyridine, methylpyridines or mixtures thereof and also cobalt catalysts at elevated temperatures and under superatmospheric pressure and subsequent treatment with molecular oxygen containing gases in aqueous acetic acid by

Recovery of pyridine or methylpyridines or mixtures thereof from methyl

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Weisenheim, Germany

Wilfried Seyfert