| 摘要 |
The invention relates to a process for preparing formic acid, in which catalytic hydrogenation of carbon dioxide with hydrogen over a catalyst which comprises a metal of groups 8 to 10 of the Periodic Table in the presence of a primary, secondary and/or tertiary amine generates the corresponding ammonium formate and the ammonium formate is split by heating into formic acid and the amine, which comprises selecting the primary, secondary or tertiary amine from the amines of the formula I or mixtures thereof where R1 to R3 are the same or different and are each hydrogen, linear or branched alkyl radicals having from 1 to 18 carbon atoms, cycloaliphatic radicals having from 5 to 7 carbon atoms, aryl radicals and/or arylalkyl radicals, and at least one of the R1 to R3 radicals bears a hydroxyl group, and performing the hydrogenation in a solvent which has a boiling point of 105° C. at standard pressure, and obtaining the formic acid in the reaction mixture from the hydrogenation comprising the high-boiling solvent by thermally splitting the ammonium formate and distilling off the formic acid.
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