Isolation of dimethyl 4,4'-biphenyldicarboxylate

US5397440A · kind A · utility

Assignee

• Hoechst GmbH · DE

Inventors

• Michael Frey · Erfurt, DE
• Ulrich Hertenstein · Gablingen, DE
• Rainer Schaller · Wertingen, DE

Key dates

• Filing date: Apr 13, 1994
• Grant date: Mar 14, 1995
• Expiry date: Apr 13, 2014

Classification

• Technology area (CPC Y): Emerging Cross-Sectional Technologies
• CPC primary: Y10S203/17
• WIPO field: Organic fine chemistry
• WIPO sector: Chemistry

Abstract

Process for isolating dimethyl 4,4'-biphenyldicarboxylate from residues of DMT production, which includes first distilling the residues at a pressure of at most 7 mbar at a boiler temperature from 200.degree. to 350.degree. C., subsequently treating the distillate which distills over in the range from 230.degree. to 270.degree. C. at a pressure of, for example, 0.2 mbar for from 10 to 60 minutes with 0.7 to 10 times the amount of an organic solvent at a temperature from 70.degree. to 180.degree. C., if required, separating the clear solution from undissolved components, cooling the removed clear solution to a temperature from 45.degree. to 65.degree. C. and allowing it to crystallize at this temperature, resulting in a suspension of dimethyl 4,4'-biphenyldicarboxylate crystals from which the crystals are isolated by washing one or more times with the same or a different solvent and by drying.