CuSe₂/CeO₂ as a novel heterogeneous catalyst for reductive carbonylation of nitroarenes for generating urethanes

The reaction of CuCl₂, SeO₂, and cetyltrimethylammonium bromide (CTAB) under the CO pressure in methanol produce a black solid, which is identified as cupric diselenide, Cu^IISe₂ using various spectroscopic analyses. Impregnation of 5 wt% of CuSe₂ onto CeO₂ resulted in much more enhanced catalytic activity due to the uniform and highly dispersed particle. The reductive carbonylation of nitrobenzene (NB) as a model substrate has been examined in the presence of the CuSe₂/CeO₂ as a single component heterogeneous catalyst, which is found to exhibit excellent catalytic activity for generating methyl-N-phenyl carbamate (MPC) in a highly selective fashion. The effects of various reaction parameters such as temperature, pressure, and reaction time have been investigated. A plausible reaction mechanism using this cheap heterogeneous catalyst is also presented, especially invoking the importance of CuSe₂(μ-CO) species.