Developing efficient and stable zeolites for vapor-phase Beckmann rearrangement of cyclohexanone oxime is still a great challenge to realizeε-caprolactam(CPL)green production.In this work,the hierarchical porous sili...Developing efficient and stable zeolites for vapor-phase Beckmann rearrangement of cyclohexanone oxime is still a great challenge to realizeε-caprolactam(CPL)green production.In this work,the hierarchical porous silicalite-1 zeolites with multiple hollow structure(S-1-M)are explored by in-situ desilication−recrystallization post-treatment of spongy highway-like zeolites(S-1-S),which are synthesized through silanization synthesis of conventional bulky silicalite-1(S-1).Compared to S-1,S-1-M achieves superior catalytic performance,with improving the CPL selectivity from 85.7%to 94.1%and prolonging the catalyst lifetime from 74 to 126 h at a weight hourly space velocity(WHSV)of 6 h^(−1).Comprehensive physiochemical studies demonstrate that the highly dispersed intracrystalline cavities within S-1-M endow greater mass diffusion and better quasi acidity inducing by the enhanced H-bonds among abundant H-bonded silanols,which is cooperatively responsible for its superior catalytic performance.展开更多
A series of meso-microporous Cu-SAPO-34 catalysts were successfully synthesized by a one-pot hydrothermal crystallization method, and these catalysts exhibited excellent NH3-SCR performance at low temperature. Their s...A series of meso-microporous Cu-SAPO-34 catalysts were successfully synthesized by a one-pot hydrothermal crystallization method, and these catalysts exhibited excellent NH3-SCR performance at low temperature. Their structure and physic chemical properties were characterized by means of X-ray diffraction patterns （XRD）, Scanning electron microscopy （SEM）, Transmission electron microscopy （TEM）, N2 sorption-desorption, nuclear magnetic resonance （NMR）, Inductively Coupled Plasma-Atomic Emission spectrometer （ICP-AES）, X-ray absorption spectroscopy （XPS）, Temperature-programmed desorption of ammonia （NH3-TPD）, Ultraviolet visible diffuse reflectance spectroscopy （UV-Vis DRS） and Temperature programmed reduction （TPR）. The analysis results indicate that the high activities of Cu-SAPO-34 catalysts could be attributed to the enhancement of redox property, the formation of mesopores and the more acid sites. Furthermore, the kinetic results verify that the formation of mesopores remarkably reduces diffusion resistance and then improves the accessibility of reactants to catalytically active sites. The 1.0-Cu-SAPO-34 catalyst exhibited the high NO conversion （〉90%） among the wide activity temperature window in the range of 150- 425℃.展开更多
基金the National Key Basic Research Development Plan“973”Project(No.2006CB202508)the National Key R&D Program of China(No.2021YFA1502600)+2 种基金State Key Laboratory of Catalytic Materials and Reaction Engineering(RIPP,SINOPEC)(No.33600000-20-ZC0607-0024)the SINOPEC Project(Nos.411058 and 413025)the National Natural Science Foundation(Nos.21808244,22178347,and 22072182).
文摘Developing efficient and stable zeolites for vapor-phase Beckmann rearrangement of cyclohexanone oxime is still a great challenge to realizeε-caprolactam(CPL)green production.In this work,the hierarchical porous silicalite-1 zeolites with multiple hollow structure(S-1-M)are explored by in-situ desilication−recrystallization post-treatment of spongy highway-like zeolites(S-1-S),which are synthesized through silanization synthesis of conventional bulky silicalite-1(S-1).Compared to S-1,S-1-M achieves superior catalytic performance,with improving the CPL selectivity from 85.7%to 94.1%and prolonging the catalyst lifetime from 74 to 126 h at a weight hourly space velocity(WHSV)of 6 h^(−1).Comprehensive physiochemical studies demonstrate that the highly dispersed intracrystalline cavities within S-1-M endow greater mass diffusion and better quasi acidity inducing by the enhanced H-bonds among abundant H-bonded silanols,which is cooperatively responsible for its superior catalytic performance.
基金supported by the National Natural Science Foundation of China (Nos. 21376261, 21173270)the National Hi-Tech Research and Development Program (863) of China (No. 2015AA034603)+1 种基金the Beijing Natural Science Foundation(No. 2142027)the China University of Petroleum Fund (Nos. 20130007110007, 2462015QZDX04)
文摘A series of meso-microporous Cu-SAPO-34 catalysts were successfully synthesized by a one-pot hydrothermal crystallization method, and these catalysts exhibited excellent NH3-SCR performance at low temperature. Their structure and physic chemical properties were characterized by means of X-ray diffraction patterns （XRD）, Scanning electron microscopy （SEM）, Transmission electron microscopy （TEM）, N2 sorption-desorption, nuclear magnetic resonance （NMR）, Inductively Coupled Plasma-Atomic Emission spectrometer （ICP-AES）, X-ray absorption spectroscopy （XPS）, Temperature-programmed desorption of ammonia （NH3-TPD）, Ultraviolet visible diffuse reflectance spectroscopy （UV-Vis DRS） and Temperature programmed reduction （TPR）. The analysis results indicate that the high activities of Cu-SAPO-34 catalysts could be attributed to the enhancement of redox property, the formation of mesopores and the more acid sites. Furthermore, the kinetic results verify that the formation of mesopores remarkably reduces diffusion resistance and then improves the accessibility of reactants to catalytically active sites. The 1.0-Cu-SAPO-34 catalyst exhibited the high NO conversion （〉90%） among the wide activity temperature window in the range of 150- 425℃.
