不同分子筛上1-己烯骨架异构化反应性能的研究

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

  • 摘要: 以HZSM-35、HZSM-5、HM和Hβ四种分子筛为1-己烯骨架异构化催化剂,比较研究了四种催化剂的异构化性能,对其构效关系进行了关联。结果表明,相比于HZSM-5和Hβ分子筛,HZSM-35和HM具有适宜的酸量,有效孔径为0.4-0.6 nm,而且无晶穴、无交叉孔道,具有良好的择形催化效应,在转化率高达95%的同时,C5-和C7+等副产物的收率在20%左右,异己烯收率可达40%-50%。进一步对四种分子筛进行酸碱改性处理,结果显示,虽然酸性质略有改变,但是一维孔结构的HZSM-35和HM分子筛的异构化性能仍明显优于多维孔结构的HZSM-5和Hβ分子筛,说明在酸性质一定的前提下,孔结构对异构化反应起关键作用。

     

    Abstract: 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 C5- 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.

     

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