THE HYDROGENATION AND HYDROFORMYLATION OF ALKENES AS CATALYZED BY POLYMER-ANCHORED RHODIUM TRICHLORIDE UNDER WATER-GAS SHIFT REACTION CONDITIONS

The 'heterogenized' water gas shift catalyst Rh/P4VP, prepared from th e reaction of RhCl3 with poly(4-vinylpyridine), is also active for hyd rogenation and hydroformylation of I-hexene and cyclohexene in aqueous ethoxyethanol under mild shift reaction conditions (typically 0.9 atm . P-CO at 100 degrees). The catalytic activities for these systems wer e studied as functions of several experimental variables. Hydroformyla tion rates increased with the P-CO but exhibited saturation behavior i n the 1.5 atm, range. Rates for cyclohexane and hexane production were inhibited by CO at higher pressures. Cyclohexene hydroformylation and hydrogenation turnover frequencies were independent of the polymer-lo ading (50-150 mu M RhCl3/1.0 g P4VP) indicating that the active specie s are of the same nuclearity as the principal species present. The tem perature dependence did not follow simple Arrhenius behavior, but appe ared segmented, These data are discussed in terms of possible mechanis ms. (C) 1998 Elsevier Science S.A.