Basf Aktiengesellschaft

Jan Jacobs

Ulrich Penzel

Hans Volkmar Schwarz

Volker Scharr

Eckhard Str&ouml;fer

Wilfried Seyfert

Olaf Schweers

Joachim Pfeffinger

Filip Nevejans

Eckhard Ströfer

Frank Poplow

Peter Van Den Abeel

Willy Van Pee

Dieter Starosta

J&uuml;rgen Dosch

Hilmar Boesel

Fritz N&auml;umann

A process for preparing methylenedianiline by reacting aniline with formaldehyde in the presence of acid catalysts comprising, in a semicontinuous process, introducing aniline with or without acid catalyst, feeding formaldehyde with or without acid catalyst through a mixing element into a circuit in which aniline with or without acid catalyst and with or without previously added formaldehyde is circulated and, after feeding in at least 50% of the total amount of formaldehyde to be fed in, heating the reaction mixture to a temperature above 75&#xb0; C. In addition, the invention relates to a process for preparing polyisocyanates by phosgenation of amines obtainable in this manner and to the polyisocyanates obtainable by this process.

Process for preparing methylenedianiline and methylenebis (phenylisocyanate)

Process for preparing methylenedianiline and methylenebis(phenyl isocyanate)

In a process for preparing mixtures of diphenylmethane diisocyanates and polyphenylpolymethylene polyisocyanates having a reduced content of chlorinated by-products and a reduced iodine color number by two-stage reaction of the corresponding mixtures of diphenylmethanediamines and polyphenylpolymethylenepolyamines with phosgene in the presence of at least one inert organic solvent at elevated temperature, separation of the excess phosgene and solvent after the phosgenation is complete and thermal treatment of the reaction product, the mass ratios of phosgene to hydrogen chloride in the residence time apparatus of the second stage of the phosgenation are at the same time 10-30:1 in the liquid phase and 1-10:1 in the gas phase.

METHOD FOR PRODUCING MIXTURES CONSISTING OF DIPHENYLMETHANE DIISOCYANATES AND POLYPHENYLENE-POLYMETHYLENE-POLYISOCYANATES CONTAINING A REDUCED AMOUNT OF CHLORINATED SECONDARY PRODUCTS AND WITH A REDUCED IODINE COLOR INDEX

A process for preparing methylenedianiline by reacting aniline with formaldehyde in the presence of acid catalysts comprising, in a semicontinuous process, introducing aniline with or without acid catalyst, feeding formaldehyde with or without acid catalyst through a mixing element into a circuit in which aniline with or without acid catalyst and with or without previously added formaldehyde is circulated and, after feeding in at least 50% of the total amount of formaldehyde to be fed in, heating the reaction mixture to a temperature above 75&deg; C. In addition, the invention relates to a process for preparing polyisocyanates by phosgenation of amines obtainable in this manner and to the polyisocyanates obtainable by this process.

Method for the production of methylenedi(phenylamine and methylenedi(phenyl isocyanate)

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Hoogerheide, Netherlands

Jan Jacobs