Aromatics are important basic chemicals. However, direct conversion of syngas via the conventional Fischer-Tropsch synthesis produces little aromatics. We presented herein that a bifunctional composite of ZSM-5 in com...Aromatics are important basic chemicals. However, direct conversion of syngas via the conventional Fischer-Tropsch synthesis produces little aromatics. We presented herein that a bifunctional composite of ZSM-5 in combination with Zn Cr Oxcatalyzes syngas conversion to aromatics. Particularly, ZSM-5 crystals with a sheet-like morphology can enhance significantly the aromatization activity. The lower length ratio of the b/a axes of the crystals, the more aromatics form but without influencing the selectivity of small molecules such as CH4 and C2–C4. Since the acid properties and the Al chemical environment were not altered while the morphology changed, the enhanced aromatic selectivity is likely attributed to the favored diffusion of aromatics in these sheet-like crystals.展开更多
Zeolites have been regarded as one of the most important catalysts in petrochemical industry due to their excellent catalytic performance. However, the sole micro- pores in zeolites severely limit their applications i...Zeolites have been regarded as one of the most important catalysts in petrochemical industry due to their excellent catalytic performance. However, the sole micro- pores in zeolites severely limit their applications in oil refining and natural gas conversion. To solve the problem, mesoporous zeolites have been prepared by introducing mesopores into the zeolite crystals in recent years, and thus have the advantages of both mesostructured materials （fast diffusion and accessible for bulky molecules） and micro- porous zeolite crystals （strong acidity and high hydro- thermal stability）. In this review, after giving a brief introduction to preparation, structure, and characterization of mesoporous zeolites, we systematically summarize catalytic applications of these mesoporous zeolites as efficient catalysts in oil refining and natural gas conversion including catalytic cracking of heavy oil, alkylation, isomerization, hydrogenation, hydrodesulfurization, methane dehydroaromatization, methanol dehydration to dimethyl ether, methanol to olefins, and methanol to hydrocarbons.展开更多
SSZ-39 zeolite with AEI framework structure is a good catalyst candidate for the methanol-to-olefins(MTO)reaction.However,the diffusion limitation and coke formation often results in fast deactivation of the SSZ-39 ze...SSZ-39 zeolite with AEI framework structure is a good catalyst candidate for the methanol-to-olefins(MTO)reaction.However,the diffusion limitation and coke formation often results in fast deactivation of the SSZ-39 zeolite catalyst.One solution for this challenge is to introduce mesoporosity in the SSZ-39 zeolite.Herein,we report the synthesis of mesoporous SSZ-39 zeolite using an organosilane surfactant,,-dimethyl--(3-(trimethoxysilyl)propyl)octan-1-aminium chloride,as a mesopore template and,-dimethyl--2,6-dimethylpiperidinium as a micropore template.The obtained zeolites were characterized by X-ray diffraction,N sorption,scanning electron microscopy,temperature programmed desorption of ammonia,and magic angle spinning nuclear magnetic resonance of Al.The results show that the mesoporous SSZ-39 zeolite has high crystallinity,meso/microporosity,high surface area,cuboid morphology,and abundant acidic sites.More importantly,this mesoporous SSZ-39 zeolite exhibits enhanced catalyst lifetime in the MTO reaction due to the presence of mesoporosity for fast mass transfer,compared with a conventional SSZ-39 zeolite without mesoporosity.展开更多
基金financially supported by the Ministry of Science and Technology of China(no.2017YFB0602201)the National Natural Science Foundation of China(Grant no.21425312,91645204 and 21621063)
文摘Aromatics are important basic chemicals. However, direct conversion of syngas via the conventional Fischer-Tropsch synthesis produces little aromatics. We presented herein that a bifunctional composite of ZSM-5 in combination with Zn Cr Oxcatalyzes syngas conversion to aromatics. Particularly, ZSM-5 crystals with a sheet-like morphology can enhance significantly the aromatization activity. The lower length ratio of the b/a axes of the crystals, the more aromatics form but without influencing the selectivity of small molecules such as CH4 and C2–C4. Since the acid properties and the Al chemical environment were not altered while the morphology changed, the enhanced aromatic selectivity is likely attributed to the favored diffusion of aromatics in these sheet-like crystals.
文摘Zeolites have been regarded as one of the most important catalysts in petrochemical industry due to their excellent catalytic performance. However, the sole micro- pores in zeolites severely limit their applications in oil refining and natural gas conversion. To solve the problem, mesoporous zeolites have been prepared by introducing mesopores into the zeolite crystals in recent years, and thus have the advantages of both mesostructured materials （fast diffusion and accessible for bulky molecules） and micro- porous zeolite crystals （strong acidity and high hydro- thermal stability）. In this review, after giving a brief introduction to preparation, structure, and characterization of mesoporous zeolites, we systematically summarize catalytic applications of these mesoporous zeolites as efficient catalysts in oil refining and natural gas conversion including catalytic cracking of heavy oil, alkylation, isomerization, hydrogenation, hydrodesulfurization, methane dehydroaromatization, methanol dehydration to dimethyl ether, methanol to olefins, and methanol to hydrocarbons.
基金the National Key Research and Development Program of China(Grant No.2017YFC0211101)the National Natural Science Foundation of China(Grant Nos.21333009,21703203 and 21673205).
文摘SSZ-39 zeolite with AEI framework structure is a good catalyst candidate for the methanol-to-olefins(MTO)reaction.However,the diffusion limitation and coke formation often results in fast deactivation of the SSZ-39 zeolite catalyst.One solution for this challenge is to introduce mesoporosity in the SSZ-39 zeolite.Herein,we report the synthesis of mesoporous SSZ-39 zeolite using an organosilane surfactant,,-dimethyl--(3-(trimethoxysilyl)propyl)octan-1-aminium chloride,as a mesopore template and,-dimethyl--2,6-dimethylpiperidinium as a micropore template.The obtained zeolites were characterized by X-ray diffraction,N sorption,scanning electron microscopy,temperature programmed desorption of ammonia,and magic angle spinning nuclear magnetic resonance of Al.The results show that the mesoporous SSZ-39 zeolite has high crystallinity,meso/microporosity,high surface area,cuboid morphology,and abundant acidic sites.More importantly,this mesoporous SSZ-39 zeolite exhibits enhanced catalyst lifetime in the MTO reaction due to the presence of mesoporosity for fast mass transfer,compared with a conventional SSZ-39 zeolite without mesoporosity.
