Water gas shift reaction and nitrobenzene reduction catalysis by tetracarbonyldi-μ-chlorodirhodium(I) complex immobilized on poly(4-vinylpyridine)

The preparation, characterization and catalytic properties of Rh2(CO)4Cl2 immobilized on poly(4-vinylpyridine) are reported. The polymer-immobilized Rh catalyst in contact with 80% aqueous 2-ethoxyethanol is active for the water gas shift reaction and nitrobenzene reduction to azoxybenzene under carbon monoxide at 100 °C. The polymer-immobilized Rh complex was found to be reusable. The Rh complex was coordinatively bonded to the pyridine groups of the organic polymer as suggested by UV–Vis/diffuse reflectance (UV–Vis/DR), Fourier transform infrared (FT-IR), and electron paramagnetic resonance (EPR) spectroscopies. The morphology and the elemental analysis of the immobilized catalyst were studied by scanning electron microscopy–energy dispersive X-ray (SEM–EDX) technique.