A series of B?MFI zeolites were synthesized using a solvent?free method using tetrapropylammonium hydroxide (TPAOH) as a template. XRD, SEM, N₂ adsorption desorption, in situ infrared spectroscopy, and pyridine adsorption infrared spectroscopy were used to characterize the effect of template agent addition on the physicochemical properties of B?MFI zeolites, and the performance of 1?butene double bond isomerization reaction was investigated. The results showed that the addition of template significantly affected the grain size and skeleton boron species content of B?MFI zeolites. When the template agent addition was 4.500 g (n（SiO₂）/n（TPAOH)=11.6）, the B?MFI zeolites obtained had the smallest particle size and the largest number of silicon boron hydroxyl pits, providing more highly active reaction sites. The reaction evaluation results confirmed that when using B?MFI molecular sieve catalyst for the double bond isomerization of 1?butene, the conversion rate of 1?butene was as high as 70.00%, and the selectivity of 2?butene was greater than 99%. The catalyst had excellent stability and showed no signs of deactivation during the evaluation period.

Pt0.5?Snx/γ?Al₂O₃ catalysts with different Sn loads were prepared by constant volume sequential impregnation method and ultrasonic shock method to improve metal dispersion. The catalysts were characterized by XRD, BET, H₂?TPR, CO?IR and TG, and the effects of Sn content on the active center structure and propane dehydrogenation performance of Pt0.5?Snx/γ?Al₂O₃ catalysts were investigated. The results showed that adjusting the n（Pt）/n（Sn） by changing the Sn content in the samples would lead to the difference in the spatial distribution of Pt and Sn species, and thus affect the mode of action between Pt and Sn. With the increase of Sn, the interaction between Pt?Sn helps to increase the dispersion of Pt, the number of active sites, the improvement of the reaction activity of the catalyst. However, when excessive Sn is introduced, a Pt?Sn alloy is formed, resulting in the coating of Pt, resulting in a decrease in the number of active sites and a decline in the reactivity.

A nitrogen?doped carbon catalyst was prepared by the calcination of the CN _y precursor synthesized by the polymerization of paraformaldehyde,1,3,5?trimethylbenzene and p?phenylenediamine.This paper also investigated the effect of catalyst calcination temperature on the performance of acetylene hydrochlorination.The results indicate that CN _y ?700?1 catalyst has the best reaction activity.It has an acetylene conversion of up to 89.8% under the optimized conditions of acetylene?to?hydrogen chloride volume ratio of 1.0∶1.1,reaction temperature of 280 ℃ and GHSV(C₂H₂) of 90 h^-1.The catalyst characterization manifests that the activity of the catalyst is related to the specific surface area,pore volume,and pyrrole nitrogen content.The active site of the catalyst is the carbon atom bonding with the pyrrole nitrogen atom.Increasing the calcination temperature results in a larger specific surface area within a certain temperature range,and the pyridine nitrogen can also be converted to pyrrole nitrogen to a certain extent.The main cause of catalyst deactivation is carbon deposit.

Supported SnCl₂ is a mercury?ree catalyst for acetylene hydrochlorination.5.0%Sn(acac)₂Cl₂/AC catalyst was prepared by introducing acetylacetone ligand to enhance the catalytic performance of SnCl₂ in acetylene hydrochlorination.The results show that the acetylene conversion of 5.0%Sn(acac)₂Cl₂/AC catalyst is up to 96% under the conditions of acetylene?to?hydrogen chloride molar ratio of 1∶1.1,170 ℃ and GHSV(C₂H₂) of 90 h^-1, which is higher than that of the 5.0%SnCl₂/AC catalyst. The physical and chemical properties of the catalysts before and after the reaction also proved that the introduction of acetylacetone ligand can enhance the acetylene adsorption capacity of the SnCl₂ catalyst and inhibit Sn loss during the reaction.Therefore,the activity and stability of the SnCl₂ catalyst were effectively improved.

The hierarchical zeolite has become a hotspot in the current molecular sieve research field due to its advantages of efficient mass transfer and shape selection catalysis.The unclear mass transfer optimization mechanism has become a bottleneck restricting the design and development of hierarchical zeolite.This paper briefly introduces recent research and development status of the hierarchical zeolite,reviewes with emphasis the research progress in mass transfer mechanism of Hierarchical zeolite,the current research challenges and the analysis of current research strategy etc,and discussed the significance of mass transfer mechanism in the research and development of graded porous molecular sieve materials and the prospect of future development.