Process for the preparation of terephthalic acid and its isomers

US5679848A · kind A · utility

Assignee

• Huels Aktiengesellschaft · DE

Inventors

• Hermann-Josef Korte · Haltern, DE
• Anton Schoengen · Witten, DE
• Christoph Schwarz · Burnaby, CA
• Thomas Jostmann · Dülmen, DE

Key dates

• Filing date: Jan 18, 1996
• Grant date: Oct 21, 1997
• Expiry date: Jan 18, 2016

Classification

• Technology area (CPC C): Chemistry; Metallurgy
• CPC primary: C07C51/09
• WIPO field: Organic fine chemistry
• WIPO sector: Chemistry

Abstract

A process for the preparation of terephthalic acid (TA) from pure dimethyl terephthalate (DMT) and/or DMT intermediate product by hydrolysis in a countercurrent reactor at a conversion of greater than 99% and crystallization to give the solid product, characterized in that the sum of the stripping steam (S) and reaction water (W) satisfies the relationship EQU L.ltoreq.S+W.ltoreq.2L, wherein (L) represents the amount of water necessary to keep the terephthalic acid (TA) produced largely in solution during the reaction and in the bottom of the reactor, and the terephthalic acid produced is crystallized in a crystallization which is free from washing stages.