Hydrazine as facile nitrogen source for direct synthesis of amines over a supported Pt catalyst

Abstract

Facile preparation of secondary amines from alcohols or aldehydes is achieved by using the hydrazine (N2H4) as an easy-to-handle nitrogen source. The anatase titania-supported Pt (Pt/TiO2-A) is discovered to be an efficient catalyst to enable the first alcohols/aldehydes to amines conversion with N2H4 as the only nitrogen and hydrogen source without any additional base or additives. Mechanistic studies suggest that this alcohol-to-amine transformation proceeds by the sequential alcohol dehydrogenation, aldehyde-N2H4 condensation, azine reduction, imine formation, and reduction processes in one pot. As N2H4 is a strong nucleophile that readily reacts with aldehyde, the unique catalytic property of Pt/TiO2-A ensures the high selectivity of amine products by providing multifunctional active sites for dehydrogenation and multiple reductions. This study highlights the considerable potential of hydrazine in direct synthesis of nitrogen-containing fine chemicals with a fine-tuned heterogeneous Pt catalyst, which is safe, green, and easy to handle.