Basf Aktiengesellschaft

Eckhard Str&ouml;fer

Hans Volkmar Schwarz

Ulrich Penzel

Volker Scharr

Jan Jacobs

Otto Watzenberger

Michael Sander

Wilfried Seyfert

Olaf Schweers

Markus Maurer

Ekkehard Schwab

Hans-Josef Sterzel

Peter Zehner

Markus Weber

Heiner Schelling

Hans Hasse

Joachim Pfeffinger

Filip Nevejans

Frank Poplow

Dominic Vanoppen

J&ouml;rg Therre

Stephan Scholl

Hans-Michael Schneider

Peter Van Den Abeel

Ralf B&ouml;hling

Dieter Starosta

Willy Van Pee

Dieter St&uuml;tzer

Rene Leuthold

J&ouml;rn M&uuml;ller

Peter Mauer

Siegfried Richter

Burghard Hantel

J&uuml;rgen Dosch

Hilmar Boesel

Fritz N&auml;umann

Process for preparing methylenedianiline and methylenebis(phenyl isocyanate)

Hydroxylamine solutions stabilized using tri(4-(2,3-dihydroxyphenyl)-4-oxabutyl)amine, tri(4-(2,3-dihydroxyphenyl)-4-keto-3-azabutyl)amine or salts thereof, and methods of stabilizing hydroxylamine solutions using these compounds.

Stabilizing agent for hydroxylamine solutions

A process for working up distillation residues from the synthesis of tolylene diisocyanate by reaction of the distillation residues with water comprises reacting the TDI distillation residues with water in a continuous or semicontinuous process in a backmixed reactor in the presence of hydrolysate.

Work-up of distillation residues from the synthesis of toluene diisocyanate

A method of reacting a solution comprising a mixture of chemical compounds which are in chemical equilibrium with one another with at least one further chemical compound ( ) is provided. The method comprises the following steps: fractionation of the solution by means of a separation method to give at least two fractions ( ) which are enriched in different chemical compounds of the mixture; and reaction of a fraction ( ) with the further chemical compound or compounds ( ). The fractionation is advantageously carried out using a film evaporator ( ). Unreacted fractions ( ) can be recirculated via a residence time vessel ( ) back to the fractionation step. The method is particularly suitable for reactions of an aqueous formaldehyde solution in which various components of the solution (formaldehyde, methylene glycol, polyoxymethylene glycols) react in different ways.

Reaction of a solution comprising a mixture

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)

The invention relates to a process for the preparation of amines by hydrogenation of nitro compounds, which comprises carrying out the hydrogenation in a vertical reactor whose length is greater than its diameter, having a downward-facing jet nozzle arranged in the upper region of the reactor through which the starting materials and the reaction mixture are fed in, and having an outlet at any desired point of the reactor, through which the reaction mixture is fed back to the jet nozzle in an external circuit by means of a conveying means, and having flow reversal in the lower region of the reactor.

Method for producing amines

An aqueous solution of free hydroxylamine is prepared by treating a hydroxylammonium salt with ammonia by the countercurrent method in a stripping column by a process in which hydroxylamine is liberated and at the same time the solution obtained is separated by distillation into an aqueous hydroxylamine solution and a salt fraction. The novel process can be carried out in a simple and gentle manner and on a large scale. The danger of decomposition is minimized owing to the low thermal load, the low concentration of hydroxylamine and the short residence time in the process.

Preparation of an aqueous solution of free hydroxylamine

Growing community of inventors

Mannheim, Germany

Eckhard Ströfer

Growing community of inventors

Mannheim, Germany

Eckhard Str&ouml;fer

Eckhard Ströfer