Preparation of formic acid by thermal cleavage of quaternary ammonium formates

US5294740A · kind A · utility

Assignee

• BASF SE

Inventors

• Hans Kiefer · Leopoldshafen, DE
• Leopold Hupfer · Friedelsheim, DE
• Ferdinand Lippert · Bad Dürkheim, DE

Key dates

• Filing date: Mar 31, 1993
• Grant date: Mar 15, 1994
• Expiry date: Mar 31, 2013

Classification

• Technology area (CPC C): Chemistry; Metallurgy
• CPC primary: C07C51/02
• WIPO field: Organic fine chemistry
• WIPO sector: Chemistry

Abstract

A process for preparing formic acid by thermal cleavage of quaternary ammonium formates of the general formula I ##STR1## where R.sup.1, R.sup.2 and R.sup.3 are C.sub.1 - to C.sub.14 -alkyl, C.sub.3 - to C.sub.8 -cycloalkyl, aryl or C.sub.7 - to C.sub.16 -aralkyl, or together are 1,4- or 1,5-alkylene which is unsubstituted or substituted one to four times by C.sub.1 -to C.sub.4 -alkyl, with the proviso that the sum of the carbon atoms of R.sup.1, R.sup.2 and R.sup.3 in the quaternary ammonium formates I is 7 to 40, comprises carrying out the cleavage in the presence of secondary formamides of the general formula II ##STR2## where R.sup.4 and R.sup.5 are C.sub.2 - to C.sub.10 -alkyl, C.sub.3 - to C.sub.8 -cycloalkyl, aryl or C.sub.7 - to C.sub.16 -aralkyl, or together are 1,4- or 1,5-alkylene which is unsubstituted or substituted one to four times by C.sub.1 - to C.sub.4 -alkyl, which formamides boil 30.degree. to 150.degree. C. lower than the tertiary amine of the general formula III ##STR3## where R.sup.1, R.sup.2 and R.sup.3 have the abovementioned meanings, contained in the formate I.