Rational design of aqueous tertiary amine solvent for integrated CO2 capture and hydrogenation

Several tertiary amine solutions with different structures were tested in the integrated CO₂ capture and hydrogenation process in the presence of heterogeneous Pd/NAC catalysts. The tertiary amines of 3-dimethylamino-1,2-propanediol (3DMA-1,2-PD) and 3-diethylamino-1,2-propanedio (3DEA-1,2-PD) with high CO₂ absorption capacity and high formate yield were selected as suitable candidates as CO₂ capture and hydrogenation solvents. Under mild reaction conditions, a high formate yield of 68% was achieved when using 1 M 3DMA-1,2-PD solution with CO₂ loading of 0.5 mol amine/mol CO₂. In addition, the physico-chemical properties of the Pd/NAC catalysts were examined and the reaction mechanism of CO₂ absorption and hydrogenation in the presence of Pd/NAC was proposed.