METHOD OF ISOLATING LOW-MOLECULAR ALIPHATIC ACIDS FROM AQUEOUS SOLUTIONS CONTAINING FORMIC ACID Russian patent published in 2003 - IPC

FIELD: industrial organic synthesis. SUBSTANCE: formic acid-containing aqueous solutions of mixture of lower aliphatic acids are treated with amines and then subjected to thermal destruction of resulting salts accompanied by distilling acids. Formic acid is bound in initial mixture by adding (i) 0.5-0.53 mole of primary or 1.0-1.03 mole secondary amines of general formula R¹R²NH, in which R¹ represents aliphatic hydrocarbon radical with 6-25 carbon atoms and R² hydrogen or aliphatic hydrocarbon radical with 1-25 carbon atoms, and (ii) 1.0- 1.03 mole of formaldehyde per 1 mole formic acid, and treatment is conducted at 50-80 C. In case of lack of tertiary amines formed in the course of reaction, specified amount of ready tertiary amines is added to provide salt formation with alcohol C2-C5-acids contained in solution. EFFECT: simplified acid separation technology. 2 cl, 5 ex