Hydrogenation of nitroarenes using polybenzimidazole-le supported rhodium catalyst

Polybenzimidazole (PBI)-supported rhodium PBI-Rh(I) catalyst was prepared and characterised by chemical analysis, IR, TGA and X-ray photoelectron spectroscopy. Sodium borohydride was used to produce active species of the catalyst. The anchored catalyst PBI-Rh(I) was found to be effective for the reduction of nitrophenols, nitrobenzoic acids and nitroanilines in methanol at room temperature and at 1 atm hydrogen. The influence of temperature, concentrations of the catalyst and substrate and nature of the solvent on the reaction rates was investigated. The recycling efficiency of the catalyst was found to be good. A probable mechanism for the catalytic reaction has been suggested. (C) 2004 Elsevier B.V. All rights reserved.