Physicochemical and catalytic properties of alumoiridium systems modified by indium in the dehydrogenation of normal higher paraffins

A study has been made of monometallic and In promoted alumoiridium catalysts for the dehydrogenation of the normal higher paraffins. It has been established that the introduction of In increases the catalytic activity and selectivity with respect to higher olefins. According to IR spectra of adsorbed CO it has been shown that introduction of In modifies the Ir surface possibly due to the formation of mixed clusters. In this process there is a decrease in the number of surface Ir atoms capable of adsorbing H₂ at 300 K but a significant increase in the number of centers for high-temperature dissociative adsorption of H₂ on the carrier. Analogous effects were observed earlier for alumoplatinum catalysts modified by In.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 10, pp. 2222–2227, October, 1991.