The Preparation and Catalytic Performance of Novel Amine-Modified Silica Supported Ruthenium Complexes for Supercritical Carbon Dioxide Hydrogenation to Formic Acid

The three kinds of amine-modified silica supported ruthenium complexes developed for the first time are effective catalysts for the synthesis of formic acid from supercritical carbon dioxide and hydrogen, the activity is comparable to that of homogeneous catalysts, TOF up to 1190 h−1 can be obtained at 100% selectivity of formic acid over “Si”—NH2—RuCl3 with bis(1,2-diphenylphosphino)ethane used as ligand. These catalysts also offer the practical advantages such as easy separation and reuse.