Effects of the Intrapellet Activity Profiles on the Selectivities in Consecutive Reactions : 1,3-Butadiene Hydrogenation over Pt/Al2O3

Experimental examinations concerning the effect of the intrapellet activity profiles on a consecutive reaction were performed. The product selectivities in the liquid-phase hydrogenation of 1,3-butadiene over Pt/Al2O3 spheres were obtained for three types of intrapellet Pt distribution profiles: a uniform catalyst with an appreciable amount of Pt present throughout the support sphere, an eggshell catalyst with a Pt band deposited at the outer surface of the support sphere, and an inner-shell catalyst with a Pt band at the middle of its radius. In all of the three profiles a whole-pellet catalyst showed product distributions and activation energies very different from that of their respective powdered form. These results are interpreted and discussed in terms of the effect of diffusional limitations.