Activity and selectivity of supported Rh complex catalyst in carbonylation of nitrobenzene

The activity and selectivity behaviour of Rh(py)3Cl3 and Rh(CO)Cl(PPh3)2 complex catalysts on various supports for carbonylation of nitrobenzene to methyl phenyl carbamate has been investigated. The best catalytic activity was shown by Rh(py)3Cl3 on γ-Al2O3 and Rh(CO)Cl(PPh3)2/ zeolites catalysts. The effect of temperature, CO pressure and initial concentration of nitrobenzene on conversion of nitrobenzene and selectivity to methyl phenyl carbamate was studied. The results have been compared with the corresponding homogeneous catalysts. Carbon monoxide interaction with supported Rh catalyst was investigated using in-situ FT-IR spectroscopy. A plausible mechanistic pathway for carbonylation of nitrobenzene has been proposed.