Preparation Of Hierarchical Structured ZSM-5 Catalyst And Its Reactivity Of Toluene Disproportionation

With the reduction of oil resources, the depth of the oil resources development and utilization is becoming a hot spot of attention. ZSM-5 zeolite is one of the most promising catalyst in petroleum processing. For example, it is essential in the production of p-xylene catalyst. ZSM-5 molecular sieve has a unique three-dimensional channel structure, adjustable silica alumina ratio, high thermal stability and good resistance to carbon deposition.In recent years, scholars have to optimize the synthesis methods, and in the synthesis process of modified modification, found that different morphology and structure of the shape-selective properties and conversion rate are affected.ZSM-5 zeolite pore zeolite molecular sieves belong to its microporous pore size not only limit its scope of application and limit their catalytic efficiency, so researchers have proposed the introduction of mesoporous pore structure in the idea that the mesoporous ZSM-5 molecular sieves. Mesoporous zeolite ZSM-5 Zeolite both hydrothermal stability of mesoporous material advantages and excellent mass transfer performance, can improve the efficiency of the catalyst reactant diffusion, thereby enhancing the reactivity. Currently, the simple introduction of the ZSM-5 system of mesoporous carbon template method is a method, the method most likely to achieve maturity. However, the use of cheap carbon particles as a template, you can not get the ZSM-5 zeolite mesoporous uniform size.In this study, first synthesized ZSM-5 were studied, and then the multi-stage hole ZSM-5 zeolite catalysts prepared using uniform size mesoporous carbon template has been explored in its final molding process. The main work is as follows:(1) The use of low purity TPAOH as the template, through exploration of the synthesis conditions to obtain the ZSM-5 zeolite. Using scanning electron microscopy (SEM) and X-ray diffraction (XRD) crystal structure and morphology of ZSM-5 zeolite were characterized. The results show that by adjusting the alcohol content, larger grains can be prepared, crystalline perfection and no other ZSM-5 zeolite crystal phase.(2) oxide modified activated carbon as a hard template, hydrothermal Synthesis multistage hole ZSM-5 zeolite catalyst method. By SEM, TEM, XRD, nitrogen adsorption-desorption, pore size analysis, NH3-TPD, and catalysts were characterized by a fixed bed reactor. The results showed that, ZSM-5 zeolite catalyst having a pore size were ordinary structure, and you can adjust the amount of carbon template to control the size and morphology of grains. In toluene disproportionation, oxidative modification template to synthesize carbon multilevel hole ZSM-5 zeolite catalyst has excellent catalytic properties, molecular sieve catalytic activity than industry.(3) The new methods is use of chitosan, molecular sieve and mixed TEOS dropped TPAOH prepared in forming globular integral molecular sieves. By SEM, nitrogen adsorption and desorption, pore size analysis, NH3-TPD were characterized. The results showed that the spherical integral molecular sieve catalyst particles uniformly, improve efficiency and diffusion of toluene disproportionation reaction has good catalytic effect, with potential industrial applications.