One catalyst for two uses: TiOx–C acts as either a photocatalyst or thermocatalyst to promote reductive amination

Abstract

The selective reductive amination of carbonyl compounds is efficiently promoted using titanium oxide uniformly doped with carbon (TiO_x–C), either as a photocatalyst or thermocatalyst. For the reductive amination of 3-phenylpropanal, 82.7% conversion of 3-phenylpropanal and 99.0% selectivity of N,N-dimethyl-3-phenylpropan-1-amine was achieved using TiO_x–C as a photocatalyst at room temperature under visible light irradiation. In addition, 98.9% conversion with 99.0% product selectivity was attained at 90 °C under no light when TiO_x–C was employed as a thermocatalyst. Therein, the efficient separation of photogenerated electron and holes of TiO_x–C is the key factor during the photocatalytic process; while, the acidic sites of the surface and oxygen vacancies of TiO_x–C are responsible for its high efficiency in the thermocatalytic reductive amination reaction.