Activity and selectivity of Rh-complex catalysts in hydroformylation of 1,4-diacetoxy-butene to vitamin A intermediate

Hydroformylation of 1,4-diacetoxy-butene using homogeneous HRh(CO)(PPh3)(3) catalyst was investigated with the aim to understand product distribution, selectivity and intrinsic kinetics. The effect of HRh(CO)(PPh3)(3) and 1,4-diacetoxy-2-butene (DAB) concentrations, and CO and H-2 partial pressures on the concentration versus time profiles was studied over a temperature range of 338-358 K. The activity and selectivity of a tethered Rh-complex catalyst on Na-Y zeolite support and a water-soluble Rh-TPPTS catalyst in a two-phase system were also studied and the performance was compared with the homogeneous catalyst. It was observed that both the tethered and biphasic catalysts were highly stable during recycle, though the activity of these catalysts was lower than the homogeneous catalyst. Rate equations have been proposed for both the hydroformylation and deacetoxylation steps. The activation energies were found to be 75.24 and 108.9 kJ/mol, respectively. (C) 2003 Elsevier Science B.V. All rights reserved.