In this work,a series of acidic montmorillonite/cordierite monolithic catalysts were prepared by a coating method using silica sol as the binder.The morphology and structure of the acidic montmorillonite/cordierite sa...In this work,a series of acidic montmorillonite/cordierite monolithic catalysts were prepared by a coating method using silica sol as the binder.The morphology and structure of the acidic montmorillonite/cordierite samples were characterized by means of X-ray diffraction(XRD),N_2 adsorption/desorption isotherms,and scanning electron microscope(SEM).The cleavage of cumene hydroperoxide(CHP) in a conventional fixed-bed reactor was chosen as a model reaction to evaluate the catalytic activity of the monolithic catalysts.The influences of acidic montmorillonite loading,reaction temperature.CHP concentration,and weight hourly space velocity(WHSV) on the catalytic activity and selectivity of phenol were studied.The results indicated that the obtained acidic montmorillonite/cordierite monolithic catalysts were firm and compact,and the loading of acidic montmorillonite was found to reach 40%(by mass) after three coating operations.The surface area of acidic montmorillonite/cordierite catalysts increases greatly as acidic montmorillonite loading increases due to higher surface area of acidic montmorillonite.Under the optimal reaction conditions(acidic montmorillonite loading of 32.5%(by mass),temperature of 80 ℃,a mass ratio of CHP to acetone of 1:3,and WHSV of CHP of 90 h^(-1)),the conversion of CHP can reach 100%,and the selectivity of phenol is up to 99.8%.展开更多
Chiral Mn Ⅲ (salen) (Jacobsen's catalyst) was axially immobilized onto a new type of organic polymer-inorganic hybrid materialzirconium poly(styrene-isopropenyl phosphonate)-phosphate(ZPS-IPPA) with different lin...Chiral Mn Ⅲ (salen) (Jacobsen's catalyst) was axially immobilized onto a new type of organic polymer-inorganic hybrid materialzirconium poly(styrene-isopropenyl phosphonate)-phosphate(ZPS-IPPA) with different linkage lengths and evaluated as catalysts for the epoxidation of unfunctionalized olefins. The results demonstrated that the prepared catalysts exhibited moderate to good activity and enantioselectivity in the asymmetric epoxidation of unfunctionalized olefins. Furthermore, the immobilized catalysts were relatively stable and could be conveniently separated from the reaction system by simple precipitation in hexane. Moreover, higher enantioselectivity was obtained with catalyst 2c than that of homogeneous counterpart catalyzed even after eight times. The excellent recycling of the catalyst was attributed to its structure feature of ZPS-IPPA which is different from either pure polystyrene or pure zirconium phosphates.展开更多
基金Supported by the National Natural Science Foundation of China(21121064,21076008,21206008)the Projects in the National Science&Technology Pillar Program during the 12th Five-Year Plan Period(2011BAC06B04)the Research Fund for the Doctoral Program of Higher Education of China(20120010110002)
文摘In this work,a series of acidic montmorillonite/cordierite monolithic catalysts were prepared by a coating method using silica sol as the binder.The morphology and structure of the acidic montmorillonite/cordierite samples were characterized by means of X-ray diffraction(XRD),N_2 adsorption/desorption isotherms,and scanning electron microscope(SEM).The cleavage of cumene hydroperoxide(CHP) in a conventional fixed-bed reactor was chosen as a model reaction to evaluate the catalytic activity of the monolithic catalysts.The influences of acidic montmorillonite loading,reaction temperature.CHP concentration,and weight hourly space velocity(WHSV) on the catalytic activity and selectivity of phenol were studied.The results indicated that the obtained acidic montmorillonite/cordierite monolithic catalysts were firm and compact,and the loading of acidic montmorillonite was found to reach 40%(by mass) after three coating operations.The surface area of acidic montmorillonite/cordierite catalysts increases greatly as acidic montmorillonite loading increases due to higher surface area of acidic montmorillonite.Under the optimal reaction conditions(acidic montmorillonite loading of 32.5%(by mass),temperature of 80 ℃,a mass ratio of CHP to acetone of 1:3,and WHSV of CHP of 90 h^(-1)),the conversion of CHP can reach 100%,and the selectivity of phenol is up to 99.8%.
基金grateful to Southwest University of China for financial supportthe Natural Science Foundation Project of CQ CSTS(2011jjA50003) for the financial support
文摘Chiral Mn Ⅲ (salen) (Jacobsen's catalyst) was axially immobilized onto a new type of organic polymer-inorganic hybrid materialzirconium poly(styrene-isopropenyl phosphonate)-phosphate(ZPS-IPPA) with different linkage lengths and evaluated as catalysts for the epoxidation of unfunctionalized olefins. The results demonstrated that the prepared catalysts exhibited moderate to good activity and enantioselectivity in the asymmetric epoxidation of unfunctionalized olefins. Furthermore, the immobilized catalysts were relatively stable and could be conveniently separated from the reaction system by simple precipitation in hexane. Moreover, higher enantioselectivity was obtained with catalyst 2c than that of homogeneous counterpart catalyzed even after eight times. The excellent recycling of the catalyst was attributed to its structure feature of ZPS-IPPA which is different from either pure polystyrene or pure zirconium phosphates.
