HOMOGENEOUS AND ALUMINA-SUPPORTED RHODIUM COMPLEX-CATALYZED HYDROGENATION

The complex Rh(OH)(CO)(PPh2)2 in homogeneous as well as in gamma-Al2O3 supported system was used as catalyst precursor for hex- 1 -ene and benzene hydrogenation at 80-degrees-C and 6.5 atm of H-2. The hydride complexes, HRh(CO)(PPh3)3 and HRh(CO) (PPh3), identified by H-1 and P-31 NMR studies, were found to be the active forms in the homogeneous system. Gamma-Al2O3 supported Rh (OH) (CO) (PPh3)2 CoMplex, activated for 2 h in hydrogen atmosphere does not change its catalytic activity for four weeks. X-ray diffraction spectra show that hydrogenation proceeds with participation of rhodium complexes rather than rhodium metal catalytic centers.