Preparation of formic acid from carbon monoxide and water

A process for the preparation of formic acid by the reaction of carbon monoxide with water at temperatures of from 100 DEG to 250 DEG C. and absolute from 100 to 350 bar, in which tertiary amines of the general formula I (I) in which R1, R2, R3 individually denote C1-C14 alkyl, C3-C8 cycloalkyl, aryl, and C7-C16 aralkyl or together denote a 1,4-alkylene group or 1,5-alkylene group optionally mono- to tetra-substituted by C1-C4 alkyl, provided that the total number of carbon atoms in R1, R2, and R3 is from 3 to 40, are added to the reaction mixture.