Basf Aktiengesellschaft

Wilfried Seyfert

Ulrich Penzel

Hans Volkmar Schwarz

Volker Scharr

Jan Jacobs

Olaf Schweers

Eckhard Str&ouml;fer

Eckhard Ströfer

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)

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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Kapellen, Belgium

Wilfried Seyfert