纳米Hβ分子筛制备过程的影响因素分析及优化

Influence Factor Analysis and Optimization of Preparation Process of Nano HβMolecular Sieve

当β分子筛的粒径达到纳米级别,不仅能够提高其反应稳定性,还能够提高某些特定反应产物的选择性。在大型石化工业中,优质的分子筛催化剂仍有很大的需求量,因此分子筛的制备仍具有研究价值。本文采用水热合成法制备Hβ分子筛,研究了不同的制备条件如硅源、铝源、搅拌温度、搅拌时间、晶化温度及晶化时间等,对Hβ分子筛晶体结构的影响。采用X射线衍射(XRD)、扫描电镜(SEM)、吸脱附技术(BET)等方法,对合成的Hβ分子筛进行了表征。结果表明,以硅溶胶为硅源,异丙醇铝为铝源,搅拌温度为25℃,搅拌时间为6h,晶化温度为160℃,晶化时间为48h,模板剂比例为0.3时,合成的Hβ分子筛的晶体指标最优。在该条件下制备的Hβ分子筛,比表面积为444 m^(2)·g^(-1),平均孔径为3.86nm,微孔比面积为357 m^(2)·g^(-1),介孔比面积为87 m^(2)·g^(-1),介孔比为0.196,平均粒径为135.01nm。

hydrothermal was used to prepare Hβbeta molecular sieves,the influences of synthesis factors(silicon source,aluminum source,stirring temperature,stirring time,crystallization temperature and crystallization time)on the crystal structure properties of Hβmolecular sieve were studied.The Hβmolecular sieves was characterized by X-ray diffraction(XRD),scanning electron microscopy(SEM),adsorption and desorption technology(BET).The results showed that when the silica sol was silicon source,the aluminum isopropoxide was aluminum source,the stirring temperature was 25℃,the stirring time was 6h,the crystallization temperature was 160℃,the crystallization time was 48h,the template ratio was 0.3,the crystal index of Hβmolecular sieve was the best.The Hβmolecular sieve prepared under these conditions had the specific surface area of 444 m^(2)/g,an average pore diameter of 3.86nm,a micropore specific area of 357 m^(2)/g,an mesoporous specific area of 87 m^(2)/g,the mesoporous ratio of 0.196,an average particle size of 135.01nm.