A comparison of different zeolites in their catalytic performance in the skeletal isomerization of 1-hexene

HZSM-35, HZSM-5, HM and Hβ zeolites were used as the catalysts for the skeletal isomerization of 1-hexene; the relationship between their catalytic performance and physicochemical properties was investigated. The results show that in comparison with HZSM-5 and Hβ, HZSM-35 and HM are provided with suitable acid amount and effective pore size between 0.4-0.6 nm, without bug hole and cross channel; as a result, the later two zeolites exhibit better shape selectivity. With a high conversion of 1-hexene (> 95%), the by-products such as C_5- and C₇₊ in the products are about 20% and the yield of iso-hexene reaches 40%-50%. After the acid-base modification treatment, a slight change in the acidity is observed; however, the catalytic performance of one-dimensional HZSM-35 and HM zeolites in pore isomerization is still much better than that of HZSM-5 and Hβ zeolites with multidimensional pore structure, suggesting that the pore structure plays a key role in the isomerization reaction.