Isobutane dehydrogenation over unimodal porous catalyst (part 1) effect ofpore distribution of Sn-Pt/ZnO/Al2O3 catalyst on dehydrogenation, activity, selectivity, and deactivation rate

The unimodal porous gamma -aluminas as carriers were applied to the Sn-Pt/Z nO/Al2O3 catalyst system for dehydrogenation of lower paraffins. Physical p roperties such as surface area, average pore diameter, pore volume of the u nimodal porous alumina carriers can be mostly reflected in the resulted cat alysts. The unimodal porous catalysts exhibit excellent activities and sele ctivities for isobutane dehydrogenation in comparison with those of the non -unimodal porous catalyst which is prepared from gamma -alumina carrier wit h broad pore distribution. Furthermore, the influence of pore diameter on s uch catalytic performances as activity, selectivity, deactivation rate are also unveiled with the unimodal porous catalysts having specific pore diame ters. It is found that pore diameter of the catalyst affects but slightly t he initial conversion of isobutane, but affects more extensively the degree of selectivity and deactivation rate, especially in the deactivation rate in which catalyst of pore diameter (16.9 nm) shows 1/3 of the deactivation rate compared with that of pore diameter (6.6 nm). Catalyst pore distributi on and pore diameter affect dehydrogenation and the application of the unim odal porous alumina carrier makes it possible to prepare unimodal porous ca talysts. ZnO is considered to be well dispersed on the unimodal porous cata lyst despite large amount of impregnation.