ZSM-11 is tetragonal, with a two-dimensional pore structure, is an important shape-selective adsorbent and catalyst for good. ZSM-5 zeolite with the same family are Pentasil, because with the structure of zeolite ZSM-5 is very similar, so the synthesis of ZSM-11 zeolite in the process is prone to ZSM-11/ZSM-5 eutectic growth phenomenon . Therefore, high purity synthetic zeolite ZSM-11 has long been the problem of many researchers. The past is mainly used tetrabutylammonium bromide or tetrabutylammonium hydroxide as templating agent in the hydrothermal synthesis of ZSM-11 system, zeolite, on the basis of this the first time in the previous four-phenyl-butyl ammonium bromide and the top three ammonium chloride as a template to synthesize a common high-purity ZSM-11 zeolite. And focus from the alkalinity, template, water content, crystallization time and crystallization temperature, and several other areas examined in detail the various factors on the crystallization process and the impact of synthetic samples. By examining the two kinds of template for the synthesis of zeolite, and found that tetrabutyl ammonium bromide or tetrabutyl ammonium hydroxide in the synthesis of ZSM-11 zeolite structure plays an important role in guiding, and phenyl trimethyl ammonium chloride presence is very necessary, plays to promote the synthesis of ZSM-11 zeolite purer, more well-crystallized role. In situ solid-phase inversion method to overcome the hot water system and some of the shortcomings of non-water system has to improve product quality, reduce cost, environmentally friendly advantages, synthetic zeolite is an ideal method. Therefore, this article hydrothermal method based on the phase inversion method using in situ solid-phase synthesis of pure ZSM-11 zeolite was investigated in the synthesis of the impact of various factors on the product, and with the conventional hydrothermal wears comparison .
The results show that in situ conversion of solid phase crystallization method can also be synthesized zeolite sample well. This system of water content in small, H_2O/SiO_2 minimum to 3 can still be a good synthesis of crystalline zeolite ZSM-11; in the case of absolute water, after numerous experiments have been amorphous product, indicating that water Solid-phase system in the heat and mass transfer plays a necessary role. In the solid-phase synthesis system, mineralizer NaF crystal nucleation played a role in the promotion, making synthesis of pure phase ZSM-11 zeolite easier. The development of hetero-atom zeolite molecular sieve synthesis and catalysis has great role in promoting, is one of the hot research in recent years, due to the introduction of a skeleton with a high catalytic activity of the hetero-atom, the zeolite has a special The catalytic properties; or modified by the modulation of these heteroatom zeolite catalyst can have a variety of functions, is a good composite catalytic materials. Therefore, growing attention in recent years heteroatom zeolite synthesis and application development. Impurity atoms in ZSM-11 zeolite is also the focus of attention. Therefore, the issue in the synthesis of pure silica ZSM-11 zeolite doped with boron atoms on the basis of further obtain pure phase, high crystallinity of B-ZSM-11 zeolite. Examined the boron atom of the zeolite synthesis process and products, and through a variety of characterization that boron atoms into the zeolite framework.
The results show that synthetic B-ZSM-11 zeolite, the ratio of raw materials in the range of Na_2O/SiO_2 than pure silicon than the synthetic zeolite ZSM-11 should be wide, and with the incorporation of boron increases, alkalinity be increased gradually. At the same time, using in situ solid-phase synthesis of doped B-ZSM-11 zeolite, compared the two systems and the synthesis of pure silica samples of zeolite ZSM-11 the similarities and differences found in B-ZSM-11 zeolite crystal cell parameters significantly less than pure silicon ZSM-11 zeolite, and the in situ solid-phase synthesis of B-ZSM-11 zeolite lattice parameters slightly larger than hydrothermal synthesis of zeolite samples. Nano-zeolite has a larger surface area, high surface energy, short-channel, etc., will help accelerate the catalytic reaction and adsorption heat and mass transfer process, thus improving catalyst utilization, enhanced reactivity and selectivity of the catalyst, extend the response operation cycle, to improve selectivity and reduce the coke deactivation, etc. have shown superior performance. Therefore, this article in the synthesis of conventional micron-ZSM-11 zeolite, based on the ratio of raw materials and by adjusting the crystallization conditions for the further synthesis of a 10nm particle size can be controlled in the suspended state within the zeolite ZSM-11 and B-ZSM- 11 zeolite, and examine the ratio of reactants and crystallization time on the synthesis of zeolite particle size, crystallinity and surface area of impact. The results show that adding alkali and ethanol can effectively reduce the crystal particle size, to extend the crystallization time can significantly increase the grain size.
The results show that in situ conversion of solid phase crystallization method can also be synthesized zeolite sample well. This system of water content in small, H_2O/SiO_2 minimum to 3 can still be a good synthesis of crystalline zeolite ZSM-11; in the case of absolute water, after numerous experiments have been amorphous product, indicating that water Solid-phase system in the heat and mass transfer plays a necessary role. In the solid-phase synthesis system, mineralizer NaF crystal nucleation played a role in the promotion, making synthesis of pure phase ZSM-11 zeolite easier. The development of hetero-atom zeolite molecular sieve synthesis and catalysis has great role in promoting, is one of the hot research in recent years, due to the introduction of a skeleton with a high catalytic activity of the hetero-atom, the zeolite has a special The catalytic properties; or modified by the modulation of these heteroatom zeolite catalyst can have a variety of functions, is a good composite catalytic materials. Therefore, growing attention in recent years heteroatom zeolite synthesis and application development. Impurity atoms in ZSM-11 zeolite is also the focus of attention. Therefore, the issue in the synthesis of pure silica ZSM-11 zeolite doped with boron atoms on the basis of further obtain pure phase, high crystallinity of B-ZSM-11 zeolite. Examined the boron atom of the zeolite synthesis process and products, and through a variety of characterization that boron atoms into the zeolite framework.
The results show that synthetic B-ZSM-11 zeolite, the ratio of raw materials in the range of Na_2O/SiO_2 than pure silicon than the synthetic zeolite ZSM-11 should be wide, and with the incorporation of boron increases, alkalinity be increased gradually. At the same time, using in situ solid-phase synthesis of doped B-ZSM-11 zeolite, compared the two systems and the synthesis of pure silica samples of zeolite ZSM-11 the similarities and differences found in B-ZSM-11 zeolite crystal cell parameters significantly less than pure silicon ZSM-11 zeolite, and the in situ solid-phase synthesis of B-ZSM-11 zeolite lattice parameters slightly larger than hydrothermal synthesis of zeolite samples. Nano-zeolite has a larger surface area, high surface energy, short-channel, etc., will help accelerate the catalytic reaction and adsorption heat and mass transfer process, thus improving catalyst utilization, enhanced reactivity and selectivity of the catalyst, extend the response operation cycle, to improve selectivity and reduce the coke deactivation, etc. have shown superior performance. Therefore, this article in the synthesis of conventional micron-ZSM-11 zeolite, based on the ratio of raw materials and by adjusting the crystallization conditions for the further synthesis of a 10nm particle size can be controlled in the suspended state within the zeolite ZSM-11 and B-ZSM- 11 zeolite, and examine the ratio of reactants and crystallization time on the synthesis of zeolite particle size, crystallinity and surface area of impact. The results show that adding alkali and ethanol can effectively reduce the crystal particle size, to extend the crystallization time can significantly increase the grain size.
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