Abstract
The study is aimed to gain understanding on the mechanism in which Sn and In promoters influence the catalyst deactivation in the course of isobutane dehydrogenation over alumina-supported Pt catalysts. A reaction scheme is postulated envisaging three types of active sites, differing by configuration, adsorption ability, contribution to the reaction routes and vulnerability by coke formations. The model relates the conditions determining the stepwise character of catalyst deactivation earlier observed with the surface fractions of acting types of sites. The approach suggests associating the kinetics of coke formation with the types of sites engaged in the structure of coke precursors.