Surfactant Aided Reductive Carbonylation of Nitrobenzene inWater Catalyzed by Pd Complexes

The catalytic carbonylation of nitroarenes is a field of high interest from a technological point of view, since provides an environmentally benign route to a number of important industrial products, such as isocyanates, carbamates, ureas, azoarenes and azoxyarenes, amines, amides, oximes and several types of heterocyclic compounds. The reductive carbonylation of nitrobenzene in water carried out by using Pd(II)-solvable catalyst precursors, leads to aniline, as major product. In the present paper we propose the micellar catalytic reductive carbonylation of nitrobenzene in water. The Pd(II) catalyst precursors tested are synthesized by using cheaper commercial insolvable ligands, such as triphenylphosphine (PPh3), 1,3- bis(diphenylphosphino)propane (dppp) and 1, 10-phenantroline (phen). The influence on the conversion and on the selectivity of such precursors has been evaluated in combination with commercial anionic (SDS), cationic (TBAB) and non ionic (Triton X 100) surfactants. We have found that all the Pd(II) complexes tested are efficiently dissolved in each O/W emulsions but the conversion is strongly influenced by the nature of ligand. By using Pd(OAc)2(PPh3)2, high selectivity towards azo- and azo-oxybenzene has been obtained. The influence of some reaction parameters has been further evaluated and optimized.