PROCEDIMENTO PER OTTENERE ACIDO FORMICO

Formic acid (I) is prepd. in a continuous process by the aq. hydrolysis of methyl formate (II) as follows: (II) and water, in the molar ratio 1:3 are added as counter-currents to a vertical column having two zones. The upper zone contains an acid sulphocationite, based on a copolymer of styrene and 2-6% divinylbenzene. Hydrolysis in the upper zone is effected at 60-100 deg.C, whilst methanol and unreacted (II) are removed. Hydrolysis in the lower zone is effected by autocatalysis at pH below 9 at 100-107 deg.C, whilst water, formic acid, and methanol are removed. The upper zone gives 70-99% of the total methanol formed, the lower zone gives 1-30% of the methanol. (I) is used for the prepn. of pharmacuticals, fungicides, herbicides, insecticides, in the leather industry, and for the preservation of prods., esp. green crops. The process gives good yields of pure prods. without requiring excessive quantities of water.