Abstract:
The invention relates to a method for producing formic acid by reacting carbon dioxide (1) with hydrogen (2) in a hydrating reactor (I) in the presence of a catalyst comprising an element from the 8 th , 9 th , or 10 th group of the periodic system; a tertiary amine containing at least twelve carbon atoms per molecule; and a polar solvent comprising one or more monoalcohols selected from methanol, ethanol, propanols, and butanols, forming formic acid / amine adducts as intermediate products, which are subsequently thermally split, wherein a tertiary amine having a boiling point at least 5°C higher than formic acid is used, and wherein a reaction mixture comprising the polar solvent, the formic acid / amine adducts, the tertiary amine, and the catalyst forms from the reaction in the hydrating reactor (I) and is discharged as a discharge (3) from the reactor.
Abstract:
A process is proposed for preparing formic acid by reaction of carbon dioxide (1) with hydrogen (2) in a hydrogenation reactor (I) in the presence of a catalyst containing an element from group 8, 9 or 10 of the Periodic Table, of a tertiary amine containing at least 12 carbon atoms per molecule, and of a polar solvent comprising one or more monoalcohols selected from methanol, ethanol, propanols and butanols, to form formic acid/amine adducts as intermediates, which are subsequently cleaved thermally, the workup of the outputs (3) from the hydrogenation reactor (I) being performed with addition of water, and this increasing the partition coefficient of the catalyst between the upper phase (4) and the lower phase.