Isolation of formic acid from its aqueous solutions

US4217460A · kind A · utility

Assignee

• BASF SE

Inventors

• Heinz Hohenschutz · Mannheim, DE
• Johannes E. Schmidt · Ludwigshafen, DE
• Hans Kiefer · Leopoldshafen, DE

Key dates

• Filing date: Apr 6, 1978
• Grant date: Aug 12, 1980
• Expiry date: Apr 6, 1998

Classification

• Technology area (CPC Y): Emerging Cross-Sectional Technologies
• CPC primary: Y10S203/22
• WIPO field: Organic fine chemistry
• WIPO sector: Chemistry

Abstract

Carboxylic acids of the general formula I EQU R.sup.1 -COOH I where R.sup.1 is hydrogen, methyl, ethyl or vinyl, are isolated from their dilute aqueous solutions by extraction followed by distillation of the mixtures obtained, the extractant used being a secondary amide of the general formula II ##STR1## where R.sup.2 and R.sup.3 are alkyl, cycloalkyl, aryl or aralkyl or conjointly are 1,4- or 1,5-alkylene, in each case of not more than 8 carbon atoms, with the proviso that the sum of the carbon atoms of R.sup.2 and R.sup.3 is from 7 to 14 and that only one of these radicals is aryl, and where R.sup.4 is one of the radicals R.sup.1.