Basf Aktiengesellschaft

Alfons Ludwig

Gunter Pipper

Gunnar Schornick

Matthias Kroner

Ralf Mohrschladt

Thomas Meyer

Wolfgang Harder

Volker Schwendemann

Volker Hildebrandt

Axel Wilms

Robert Weiss

Rainer Neuberg

Peter Hildenbrand

J&ouml;rg Erbes

Dieter Krauss

Thomas Sauer

Reinhard Lang

Walter G&ouml;tz

Udo Metzmann

Hans-Jacob Feindt

Hans-Harald H&uuml;nger

Dieter Keller

Ragnhild Pille

Uwe Strotmann

J&uuml;rgen Deininger

An apparatus ( ) is proposed for drying and heat-treating pellets with a stream of inert gas, wherein the apparatus has a cuboid base unit ( ) with a feed ( ) for the pellets in its upper part and an outlet ( ) in its lower part, with a feed ( ) on one lateral surface and with an exhaust base ( ) on the opposite lateral surface of the cuboid base unit ( ) for the stream of inert gas, and also with distribution and retention equipment ( ) in the region of the feed ( ) and, respectively, of the exhaust ( ) for the stream of inert gas, where each of these extends essentially over the entire vertical cross section of the cuboid base unit ( ).

Device for drying and thermally treating granulates with an inert gas stream

Method for the continuous production of copolyamides based on a lactam (I), a diamine (II) and a dicarboxylic acid (III)

A process for producing polyamides by reacting at least one lactam and optionally further polyamide-forming monomers with aqueous monomer and oligomer extracts obtained during the extraction with water of the polymer product obtained in the production of polyamides, the water content of the reaction mixture being in the range from 0.5 to 13% by weight comprises conducting the reaction in the presence of metal oxides, beta-zeolites, sheet-silicates or silica gels, which may be doped, as heterogeneous catalysts, the heterogeneous catalysts being used in the form which permits mechanical removal from the reaction mixture and are removed from the reaction mixture in the course of the polymerization or after it has ended.

Method for preparing polyamides from lactams and polyamide extracts

The disclosure is a process for preparing polyamides by concentrating the wash water extract from the extraction of polyamide to an extractables content of not more than 85% by weight, adding fresh lactam down to a water content of from 0.5 to 13% by weight, and effecting at least one adiabatic expansion during the polymerization.

Preparation of polyamides

A process for continuous extraction of polyamide particles using a recirculating extractant in a vertical extraction column that is divided into two zones comprises treating the polyamide with an aqueous extractant comprising from 40 to 95% by weight of &egr;-caprolactam in a first zone at from 100 to 140&deg; C., and then effecting an aftertreatment with water in a second zone. The caprolactam can then be extracted in a conventional manner. The process provides for economical production of polyamide having a low dimer content.

Continuous polyamide extraction process

A process for continuous extraction of polyamide particles in an essentially vertical extraction column using an aqueous extractant comprises using an extraction column that is divided into two zones and performing an extraction with a recirculating 15-40% strength by weight aqueous &egr;-caprolactam solution in the first zone and then with countercurrent water at a from 5 to 40&deg; C. lower temperature in the second zone. The process provides for economical extraction of polyamides with a low level of monomers and oligomers.

Process for producing polyamides from aminonitriles

Preparation of salts of polyaspartic acid and their use in detergents

Preparation of polyaspartic acid

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Höxter, Germany

Alfons Ludwig