高效可回收多相催化剂SiO_2-Cu_2O催化伯胺和仲胺苄基化反应(英文)

A mild,effective,and selective procedure is reported for the mono N-benzylation and N,N-dibenzylation of primary amines as well as mono N-benzylation of secondary amines using silicasupported copper(I) oxide in water.The silica-supported Cu2O was generated in situ by the reaction of Fehling solution and glucose at 100 °C onto activated silica.The catalyst was filtered,washed with water,and oven-dried,and was characterized by Fourier transform infrared spectroscopy,thermogravimetric analysis,scanning electron microscopy,transmission electron microscopy,and atomic absorption spectroscopy.The prepared Cu2O-SiO2 was found to be thermally stable up to 325 °C.The copper was uniformly distributed onto the surface of the silica,and the mean particle diameter was 7 nm.The catalyst served as a selective heterogenous catalyst for the N-benzylation of primary and secondary amines.The catalyst is recyclable and was used effectively upto fifth run without a significant loss of catalytic activity.Various reaction solvents including water,acetonitrile,and toluene were screened for N-benzylation of amines,and the success of the aqueous system highlights the low environmental impact of the procedure.