Bayer Aktiengesellschaft

Lanxess Deutschland Gmbh

Klaus-Peter Heise

Karlfried Wedemeyer

Paul Wagner

Winfried Joentgen

Torsten Groth

Lutz Heuer

Thomas Menzel

Ulrich Liesenfelder

Nikolaus Muller

Hans-Georg Pirkl

Dieter Dieterich

Gerhard Grogler

Hans-Joachim Traenckner

Hermann Uhr

Robert Kuth

Ursula Pentling

Andreas Sattler

Frank Dobert

Frank D&ouml;bert

Hellmuth Pantke

J&ouml;rgen Weinschenck

Ute Wollborn

Joergen Weinschenck

Karl-Hermann Brucher

Joachim-Reinhard Wesener

Johannes Kanellakopoulos

Ernst Schneider

Karl Neufang

Axel Ingendoh

Christian Rother

The invention relates to a method for carrying out polycondensation reactions, according to which the polycondensation of a monomeric starting material is carried out with external supply of heat in a reactor combination which has at least two stages and is composed of a pre-reactor and a high-viscosity reactor, where the low-molecular-weight elimination products produced are removed by evaporation. In the pre-reactor, the reaction product is concentrated to give a high-viscosity preliminary product. The high-viscosity preliminary product is then fed to the high-viscosity reactor, in which it reacts to completion with simultaneous introduction of thermal and mechanical energy and with a residence time of from 20 s to 60 min to give a polycondensation product.

Method for carrying out polycondensation reactions

Polymers having recurring succinyl units are obtained by an improved process by reaction of A, an unsaturated C.sub.4 -dicarboxylic acid or a derivative thereof, with B, a nitrogen-donating compound, in a first reaction step to give a reaction mixture comprising at least one low molecular weight reaction product, and subsequent continuous feeding of the reaction mixture into a continuously operated reactor to give the polymer in a second reaction step. In a further embodiment the invention refers to polymers having recurring succinyl units prepared by reaction of an unsaturated C.sub.4 -dicarboxylic acid or a derivative thereof with a nitrogen-donating compound in a first reaction step and subsequent feeding of the reaction mixture, without intermediate isolation, into an optionally continuously operated reactor, with removal of water, and treatment of the reaction mixture at a temperature of 140 to 350.degree. C.

Process for the preparation of polymers having recurring agents

1-alkyl-pyrazole-5-carboxylic acid esters are prepared by reacting the enolate of a 2,4-diketocarboxylic acid ester with an N-alkylhydrazinium salt in the presence of a solvent. This process allows a particularly economic preparation of 1-alkyl-pyrazole-5-carboxylic acid esters in a simple manner and with only little formation of undesirable isomers.

Process for the preparation of 1-alkyl-pyrazole-5-carboxylic acid esters

Washing process using polycarboxylic acid salts

The polymers according to the invention with repeating succinyl units additionally contain iminodisuccinate units.

Iminodisuccinate-containing polymers

This invention relates to diaminoarylsulfones of the formula ##STR1## wherein R.sub.1, R.sub.2, and R.sub.3 are independently C.sub.1 -C.sub.12 alkyl, that are useful as chain extenders in the preparation of polyurethane elastomers.

Diaminoarylsulfones useful for the preparation of polyurethane elastomers

The light fastness of dyed polyamide fibre materials, in particular of the type used for manufacturing car seat covers, can be substantially improved by treating these materials, before, during or after the dyeing, with copper compounds of the compounds of the formula ##STR1## wherein R=H, OH, alkyl or cycloalkyl. The compounds (I) are distinguished by low self-colour and good stability to acid conditions.

Process for improving the light fastness of polyamide dyeings

The invention relates to a process for the preparation of optionally p-chlorine-substituted 2,6-diaminotoluene, which is characterized in that 3,4-dichlorotoluene is dinitrated in the presence of an inert, water-immiscible, organic solvent and/or diluent at temperatures of -10.degree. to +100.degree. C. and is subsequently reduced, optionally after intermediate isolation of the dinitro compound, in the presence of an inert organic solvent and/or diluent and/or of water, with partial or complete splitting-off of the chlorine atoms, to give the diamino compound. 2,6-Diaminotoluenes are valuable intermediates for the preparation of diisocyanates and polyurethanes; the 2,6-diaminotoluene is furthermore used for the preparation of dyestuffs and antioxidants.

Process for the preparation of optionally p-chlorine-substituted

The invention relates to a process for the preparation of 4-nitrodiphenylamines by the reaction of halogenonitrobenzenes with primary aromatic amines in the presence of copper or a copper compound, a neutralizing agent and a cyclic diaza compound.

Process for the preparation of 4-nitrodiphenylamines

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Odenthal, Germany

Klaus-Peter Heise