| abstract |
Formic acid is recovered, by distillation, from its mixtures with solvents of the general formula I <IMAGE> I where R1 is hydrogen, methyl, ethyl or vinyl and R2 and R3 are each alkyl, cycloalkyl, aryl or aralkyl, or R2 and R3 together form a 1,4- or 1,5-alkylene group, in each case of not more than 8 carbon atoms, with the provisos that the sum of the number of carbon atoms in R2 and R3 is 7 to 14 and that only one of these radicals is aryl, by a method in which the distillation is carried out in the presence of a carboxamide II which is selected from the group consisting of formamide, acetamide, propionamide and the same compounds substituted by N-methyl or N,N-dimethyl, and which has a boiling point lower than that of the solvent I. |