Oxidative aromatization of propane with CO2 over bi-functional MFI zeolite catalyst

초록

The CO2 utilization and application for high value added products such as benzene, toluene and xylenes (BTX) have been focused due to its catalytic activity and energy source of CO2. In world wide, the propane production was enhanced by digging the shale gas and byproduct from natural gas. The price for propane have been reduced continuously. The aromatization was considered by the UOP&BP that has been developed the propane aromatization named as the Cyclar process by using the Ga/ZSM-5 as a catalyst. Even the propane to aromatic yields were 66 wt%, the coke formation on catalyst appeared as problem. The ZSM-5 Zeolite, 10-membered ring, has been widely used as a catalyst for industrial applications such as cracking, isomerization, alkylation, isobutanol or methanol to hydrocarbons reactions, even aromatization. The metal species are used for the aromatization to enhancing activity via applying as a Lewis acid site. Even though metal/metal oxide system adepted for the simple dehydrogenation, oligomerization and cyclization, the reaction was carried out under inert gas not under the CO2. Applying the CO2 effect on aromatization is giving the spreading out the concept of the CO2 utilization on petroleum reaction. The CO2 enthalphy on ground state is 1650 kJ mol-1 that value means hard to activation on the reaction. In our previous result, the CO2 promoter and soft oxidant were reported that the CO2 could be active for ethylbenzene to styrene reaction as the oxi-dehydrogenation and initiated the oxidation reaction with CO2 as promoter. The aromatization mechanism was consisted of dehydrogenation, oligomerization, cyclization and aromatization. Among the process, the dehydrogenation step of propane is rate determining step. The CO2 molecules could be controlled it as water gas shift reaction in our reaction. We defined it as CO2 enhancer. The study for the roll of CO2 on surface during the aromatization is important for understanding the concept of CO2 utilization.