摘要
以类苯环形HZSM-5分子筛为核,通过动态水热法在其上外延生长一层纯硅Silicalite-1壳层,合成了HZSM-5/Silicalite-1复合分子筛催化剂,对其进行了XRD、SEM、NH3-TPD和Py-IR表征,并在连续流动固定床反应器中进行甲苯甲基化合成对二甲苯催化反应评价其催化活性。结果表明,合成的是以HZSM-5为核、Silicalite-1为壳的核壳分子筛,Silicalite-1壳层的覆盖度为86%;与纯ZSM-5相比,复合分子筛的酸性明显减弱,且酸量减少。HZSM-5/Silicalite-1复合分子筛对甲苯甲基化合成对二甲苯反应表现出了高的催化活性和较高的对位选择性,在甲苯的转化率为28.1%时,对二甲苯选择性达到74.3%。
Core-shell zeolite composite HZSM-5/Silicalite-1 was synthesized via hydrothermal procedure with continuous stirring,and characterized by XRD,SEM,NH3-TPD and Py-IR.Methylation of toluene with methanol to p-xylene over HZSM-5/Silicalite-1 core-shell zeolites in continuous flow fixed-bed reactor was carried out to evaluate the catalytic activity of HZSM-5/Silicalite-1.It was proved that HZSM-5/Silicalite-1 was really a core-shell zeolite composite with a core of HZSM-5 and a shell of Silicalite-1,and the Silicalite-1 shell reached 86%.A reduction of the acid sites and strength could also be achieved by epitaxial overgrowth of Silicalite-1 on the precursor ZSM-5 crystals,showing that HZSM-5/Silicalite-1 possessed high catalytic activity and the selectivity to p-xylene.The toluene conversion and p-xylene selectivity reached 28.1% and 74.3%,respectively.
出处
《石油学报（石油加工）》
EI
CAS
CSCD
北大核心
2011年第5期812-816,共5页
Acta Petrolei Sinica(Petroleum Processing Section)
基金
国家重点基础研究发展计划"973"前期研究专项(2007CB216402)
国家自然科学基金项目(21066011)
宁夏科技公关国际合作研究专项(08GJ-201)
宁夏自然科学基金(NXZR2009-4)资助
