Investigation of the interactions for the 1-hexene oligomerization and the catalytic cracking reactions

Using 1,3,5-triisopropylbenzene (1,3,5-TIPB) and n-octane as the catalytic cracking feedstocks and 1-hexene as the oligomerization feedstock, the coupling mechanism of catalytic cracking reaction and olefin oligomerization reaction over the synthesized hierarchical ZSM-5 zeolite catalyst was evaluated. The results of catalytic cracking reaction of model compounds showed that the catalytic cracking performance of molecules with different sizes was inhibited on the synthesized hierarchical ZSM-5 zeolite. The cracking activity of 1,3,5-TIPB decreased, and the initial activity of n-octane reduced from 70% to 20%. However, enhanced 1-hexene oligomerization activity was observed over the hierarchical ZSM-5 zeolite, with dimer as the main product. The reduction of the strong acid sites in the zeolite can inhibit the catalytic cracking reaction and promote the oligomerization of C6 olefin into dimer and trimer (ideal components of jet fuel). Therefore, the designing of the catalyst from the perspective of inhibiting the activity of catalytic cracking can effectively improve the oligomerization performance of the catalyst.