文献类型：期刊文献

中文题名：MFI/MFI核壳分子筛合成的影响因素及结晶动力学

英文题名：Crystallization Kinetics and Influencing Factors in the Syntheses of MFI/MFI Core-Shell Zeolites

作者：孔德金[1,2];邹薇[2];郑均林[2];祁晓岚[2];房鼎业[1]

机构：[1]华东理工大学化工学院,上海200237;[2]中国石油化工股份有限公司上海石油化工研究院,上海201208

年份：2009

卷号：25

期号：9

起止页码：1921

中文期刊名：物理化学学报

外文期刊名：Acta Physico-Chimica Sinica

收录：CSTPCD;;Scopus;WOS:【SCI-EXPANDED(收录号:WOS:000269961300034)】；北大核心:【北大核心2008】；CSCD:【CSCD2011_2012】；PubMed;

基金：The project was supported by the National Key Basic Research Program of China (973) (2009CB623501).

语种：中文

中文关键词：结晶动力学;ZSM-5;MFI/MFI;核壳分子筛;成核活化能;生长活化能

外文关键词：Crystallization kinetics; ZSM-5; MFI/MFI; Core-shell zeolite; Nucleation activation energy; Crystallization activation energy

摘要：以低硅铝比ZSM-5为核,采用二次生长法水热合成了MFI/MFI核壳分子筛.发现对核相分子筛进行预处理是合成的关键步骤.通过控制壳相合成过程(如合成温度、合成时间和核相分子筛加入量)可有效控制核壳分子筛的壳层生长.以异丙苯(IPB)及1,3,5-三异丙苯(1,3,5-TIPB)裂解为探针反应,发现与核相分子筛相比,核壳分子筛的IPB裂解反应活性相当.而1,3,5-TIPB裂解活性下降68%,与外表面Al含量下降程度相近,表明MFI/MFI核壳分子筛较好地保留了分子筛的核相反应活性.结晶动力学计算结果表明,MFI/MFI核壳分子筛的成核活化能为51.5kJ·mol-1,生长活化能为26.5kJ·mol-1.
MFI/MFI core-shell zeolites with a low silica to alumina ratio core and a continuous shell of high silica to alumina ratio were successfully synthesized by a novel two-step procedure. This was done by a secondary growth of the ZSM-5 shell onto the modified ZSM-5 crystals and the pre-treatment step played an important role during the synthesis. Critical factors for the growth of the ZSM-5 shell including synthesis temperatures, periods, and core dosages were summarized. Results from cumene and 1,3,5-triisopropylbenzene （1,3,5-TIPB） cracking reactions showed that the core-shell zeolite and the core crystal had comparable activities for the cumene cracking reaction. Compared to the core crystal, the cracking activity of 1,3,5-TIPB of the core-shell zeolite was reduced by 68%, which coincided with the extent of aluminum reduction on the external surface. These results suggested that the acidity of the core crystals was largely preserved in the MFUMFI core-shell structure. Crystallization kinetics curves were determined at different synthesis temperatures. The apparent energy of crystallization activation was found to be 26.5 kJ·mol^-1. and the activation energy of nucleation was 51.5 kJ·mol^-1.