Selective Transfer Hydrogenation of Cinnamaldehyde with Alcohol on Amorphous TiO 2 Catalysts: Competitive Adsorption between H 2 O and Carbonyl

Reduced amorphous TiO 2 (A‐TiO 2 ), with high coverage of electrons and protons on its surface, supplies a steady‐state condition for selective hydrogenation reaction. Generally, there are some complex hydrogenation reaction products ascribed to the presence of multiple adsorption modes of cinnamaldehyde (CAL). In our work, the saturated aldehyde (∼48%) and unsaturated alcohol (52%) coexist in the products with a ratio of near 1 : 1, while the saturated alcohol is not produced in the reaction. Furthermore, the presence of H 2 O could suppress the adsorption of the C=O group while the C=C group could be strongly adsorbed on the surface of A‐TiO 2 , which results in the high selectivity of HCAL (∼84%). We explain these results by proposing a reaction mechanism with several adsorption modes of CAL affected by the solvents. This discovery also puts forward a new method for promoting the selectivity of COL by removing the H 2 O in the reaction system.