Preparation of dimethyl butanedicarboxylates

US4256909A · kind A · utility

Assignee

• BASF SE

Inventors

• Rudolf Kummer · Bischofswerda, DE
• Heinz-Walter Schneider · Ludwigshafen, DE
• Franz-Josef Weiss · Schifferstadt, DE
• Otto Lemann · Bad Dürkheim, DE

Key dates

• Filing date: Aug 15, 1979
• Grant date: Mar 17, 1981
• Expiry date: Aug 15, 1999

Classification

• Technology area (CPC C): Chemistry; Metallurgy
• CPC primary: C07C67/38
• WIPO field: Organic fine chemistry
• WIPO sector: Chemistry

Abstract

In a process for the preparation of dimethyl butanedicarboxylates, wherein PA0 (a) butadiene or a hydrocarbon mixture containing butadiene is reacted with carbon monoxide and methanol in the presence of a tertiary nitrogen base and a cobalt carbonyl catalyst at from 80.degree. to 150.degree. C. under superatmospheric pressure, PA0 (b) the greater part of the tertiary nitrogen base and any excess hydrocarbons are removed and PA0 (c) the methyl pentenoate thus obtained is reacted with carbon monoxide and methanol, in the presence of a cobalt carbonyl catalyst and the residual amount of tertiary nitrogen base, at from 140.degree. to 200.degree. C. under superatmospheric pressure, to give the dimethyl butanedicarboxylate, the improvement that the reaction mixture obtained in stage (a) after reaction of the butadiene is cooled until it separates into two phases, and a part-stream of from 20 to 80% by volume of the lower phase is recycled to stage (a).