Mesoporous ZSM-5 catalysts for the synthesis of clean jet-fuels by 1-hexene oligomerization

Zeolite is one kind of the solid acid catalysts for the oligomerization process but surfers from rapid deactivation. In this specific study, a series of mesoporous ZSM-5 catalysts have been synthesized and evaluated in the 1-hexene oligomerization. XRD, BET, SEM, TEM, Al-27 MAS NMR, Si-29 MAS NMR, NH3-TPD, Py-FTIR and TGA analysis were used to characterize the physicochemical properties of zeolites. The synthesized mesoporous zeolites were found to be more stable in the reaction and the initial activity increase significantly compared with the common ZSM-5 zeolite. Moreover, the catalytic activity of mesoporous ZSM-5 zeolite is found to be closely related to the number and the distribution of acid sites. The mesoporous ZSM-5 zeolites with the lower amount of acid sites, moderate strength of Bronsted acid sites inhibiting the cracking and coke products. High L/B ratio enhanced the dimers formation. The efficiency was further highlighted by a high space-time yield (STY) of 557 mg.g(cat)(-1)h(-1) in the average stage at 260 degrees C. Compared to conventional ZSM-5 catalyst, the synthesized catalyst displayed excellent resistance to coke deposit.