HZSM-5沸石孔口改性及其择形分离性能  

Studies on the Control of Pore-opening Size of HZSM-5 and its Shape-selective Adsorption

作　　者：乐英红[1] 唐颐[1] 高滋[1] 

机构地区：[1]复旦大学化学系,上海200433

出　　处：《化学学报》1996年第3期248-252,共5页Acta Chimica Sinica

基　　金：国家基础研究重大项目资助课题

摘　　要：采用Si(OCH_3)_4化学气相沉积方法精细调变HZSM-5孔径,焙烧后在沸石外表面上沉积一薄层氧化硅,使沸石孔口有控制地被缩小.制备了一系列氧化硅沉积量不同的SiHZSM-5沸石,并用红外光谱,NH_3-TPD和吸附方法对其进行表征,结果表明沸石骨架结构,内孔孔容和内表面性质基本不变.测定了SiHZSM-5沸石对于二甲苯和甲酸异构体的择形吸附性能,发现在沉积量适当的SiHZSM-5沸石上能够成功地实现对二甲苯和对甲酚的择形选择吸附分离,因为沸石孔口缩小后将大的间位异构体排除在外,而沸石总吸附容量仍保持较高水平.The pore - opening size of HZSM - 5 was finely controlled by the chemical vapor deposition of Si(OCH3)4. After calcination a thin layer of silica was deposited on the external surface and narrowed the pore - opening of the zeolite effectively. A series of HZSM - 5 zeolite samples with different amount of silica deposition (SiHZSM - 5) were prepared and characterized by IR spectroscopy, NH3 - TPD and adsorption measurements. It was found that after deposition and calcination the zeolite framework structure, pore volume and internal surface properties were essentially unaltered . The shape - selective adsorption of xylene and cresol isomers on SiHZSM - 5 was investigated. The separation of p - isomer from mixed isomers of xylene or cresol can be achieved successfully by using SiHZSM - 5 with proper silica deposition extent, because the larger m - isomer molecules, are refrained from adsorption due to the narrowed pore - opening while the total adsorption capacity of the zeolite keeps at a reasonably igh level.

关 键 词：孔口改性 择形吸附 二甲苯 分离 甲酚 分子筛 

分 类 号：TQ424.25[化学工程]