CATALYSTS BASED ON THE ALUMINUM AND TITANIUM COMPOUNDS FOR PROPANE CRACKING; [КАТАЛИЗАТОРЫ НА ОСНОВЕ ОКСИДОВ АЛЮМИНИЯ И ТИТАНА ДЛЯ КРЕКИНГА ПРОПАНА]

The paper investigates regularities in the high-temperature propane conversion process using the catalytic systems containing aluminum and titanium and including a mixture of the titanium oxides with aluminum, highly porous titanium oxide, nanocomposite fibrous material and nanocrystalline composite containing aluminum and titanium, as well as with the titanium-containing zeolite of the MFI type (Mobil five). It shows that the growing number of catalytic centers and their availability is leading to an increase in the catalytic systems activity and contribution of the dehydrogenation mechanism with the propylene preferential yield. It was established that the catalyst surface developed through the micro-pores formation prevents the cracking process from proceeding by the dehydrogenation mechanism due to reduced availability of the active centers. As a result, the studied catalytic systems activity was decreasing, and the reaction predominantly was proceeding by the carbon cage destruction mechanism. Maximum propane conversion degree of 68 % with selectivity of 65 % for propylene was achieved at the temperature of 700 qC in the case of using the nanocrystalline composite material. It was established that the composite had similar values of the specific surface area and acidity compared to the titanium-containing zeolite of the MFI type. The composite material provided better adsorption of the propane molecule in the catalytic center and breaking the C–H bond. Catalytic activity of materials consisting of mechanical mixture of titanium oxide with aluminum oxide, as well as with highly porous titanium oxide, turned out to be significantly lower, than that of the composite catalyst. For all the studied catalytic systems, high resistance to surface deactivation due to the amorphous carbon deposition was noted. © Author(s), 2023.