Continuous method for producing polyamides from aminonitriles

US6815527B2 · kind B2 · utility

Assignee

• BASF SE

Inventors

• Peter Bassler · Viernheim, DE
• Helmut Winterling · Ludwigshafen, DE
• Rolf Fischer · Heidelberg, DE
• Wolfgang Loth · Bad Dürkheim, DE

Key dates

• Filing date: Jan 10, 2003
• Grant date: Nov 9, 2004
• Expiry date: Jan 10, 2023

Classification

• Technology area (CPC C): Chemistry; Metallurgy
• CPC primary: C08G69/16
• WIPO field: Macromolecular chemistry, polymers
• WIPO sector: Chemistry

Abstract

The continuous process for preparing a polyamide by reacting at least one aminonitrile with water comprises:(1) reacting at least one aminonitrile with water in the presence of an organic liquid diluent at from 90 to 400° C. and from 0.1 to 35×106 Pa in a flow tube containing a Brönsted acid catalyst selected from a beta-zeolite catalyst, a sheet-silicate catalyst or a titanium dioxide catalyst comprising from 70 to 100% by weight of anatase and from 0 to 30% by weight of rutile and in which up to 40% by weight of the titanium dioxide may be replaced by tungsten oxide, to obtain a reaction mixture,(2) further reacting the reaction mixture at from 150 to 400° C. and a pressure which is lower than the pressure in stage 1 in the presence of a Brönsted acid catalyst selected from a beta-zeolite catalyst, a sheet-silicate catalyst or a titanium dioxide catalyst comprising from 70 to 100% by weight of anatase and from 0 to 30% by weight of rutile and in which up to 40% by weight of the titanium dioxide may be replaced by tungsten oxide, the temperature and pressure being selected so as to obtain a first gas phase and a first liquid phase or a first solid phase or …