Method for the continuous production of polybutyleneterephthalate from terephthalic acid and butanediol

US6812321B1 · kind B1 · utility

Assignee

• BASF SE

Inventors

• Thomas Heitz · Ludwigshafen am Rhein, DE
• Martin Klatt · Bad Dürkheim, DE
• Ralf Neuhaus · Drensteinfurt, DE

Key dates

• Filing date: Dec 19, 2001
• Grant date: Nov 2, 2004
• Expiry date: Jan 31, 2022

Classification

• Technology area (CPC C): Chemistry; Metallurgy
• CPC primary: C08G63/183
• WIPO field: Macromolecular chemistry, polymers
• WIPO sector: Chemistry

Abstract

In a process for the continuous preparation of polybutylene terephthalate from terephthalic acid and 1,4-butanediol comprising:a) direct esterification of terephthalic acid with 1,4-butanediol in a reactor cascade comprising at least two reactors,b) precondensation of the esterification product obtained in stage a), andc) polycondensation of the precondensate obtained in stage b),the reaction pressure decreases and the temperature does not increase along the reactor cascade in stage a).