The effect of PdCl2, concentration and of carbon monoxide pressure on the rate of nitrobenzene carbonylation reaction in the presence of PdCl2/Fe/I-2/Py (Py = pyridine) catalytic system was studied. The reaction was shown to be of the first order with respect to palladium chloride and nitrobenzene concentrations as well as to carbon monoxide pressure. The effects of substituents in the aromatic ring on the rates of the nitrobenzene carbonylation, aniline carbonylation with nitrobenzene as an oxidant and the nitrobenzene reduction were also investigated. The first deoxygenation of nitrobenzene by carbon monoxide was shown to be the rate limiting step in the carbonylation reaction. The electron transfer from carbon monoxide to nitrobenzene molecule initiates the reaction. (c) 2005 Elsevier B.V. All rights reserved.