A simple preparation of an efficient heterogeneous gold catalyst for aerobic amine oxidation

Numerous sophisticated techniques have been applied in the past years for the preparation of supported gold catalysts designed for oxidation reactions. Here we show that it is possible to arrive at an efficient catalyst without using any conventional step for the synthesis of supported gold nanoparticles. The reaction studied was the oxidative dehydrogenation of amines to imines with molecular oxygen. The catalyst precursors Au(OAc)(3) and an oxide support were simply added to the reaction mixture and the active gold nanoparticles on the support were formed in situ. The corresponding imines were produced in 89-100% yield and the catalyst was proved to be truly heterogeneous and recyclable. Despite of the simplicity of the method, the activity of the catalysts was comparable, or even superior, to other known catalysts of the oxidative dehydrogenation of amines and to some commercially available supported gold catalysts. (C) 2009 Elsevier B.V. All rights reserved.