ZSM-5/MCM-41 composite molecular sieve was prepared by the nano-assembling method.The ZSM-5 molecular sieve,the MCM-41 molecular sieve,the ZSM-5/MCM-41 mechanical mixture and the ZSM-5/MCM-41 composite molecular sieve...ZSM-5/MCM-41 composite molecular sieve was prepared by the nano-assembling method.The ZSM-5 molecular sieve,the MCM-41 molecular sieve,the ZSM-5/MCM-41 mechanical mixture and the ZSM-5/MCM-41 composite molecular sieve were characterized by X-ray powder diffractometry,N_2 adsorption isotherms,temperature programmed desorption of ammonia and scanning electron microscopy and their properties were analyzed.Using FCC gasoline as the feed,activities of different molecular sieves for reducing olefin content were investigated in a continuous high-pressure micro-reactor unit under the following conditions:a reaction temperature of 400℃,a reaction time of 2 h,a weight hourly space velocity of 3h^(-1),and a reaction pressure of 2.0 MPa.The results showed that the HMCM-41 molecular sieve had low reaction performance,and the HZSM-5 molecular sieve demonstrated high aromatization activity,while the ZSM-5/MCM- 41 composite molecular sieve exhibited a best olefin-reducing performance because of its high isomerization activity and moderate aromatization activity.With a largest olefin-reducmg capability and a reasonable distribution of products,the composite molecular sieve was more suitable for FCC gasoline upgrading compared to other three catalysts.展开更多
Mesoporous molecular sieve MCM-41 has been synthesized in the extremely dense system (with H2O/Si<10) and characterized by XRD, N-2 adsorption isotherm as well as probe reactions of cracking of cumene and isomeriza...Mesoporous molecular sieve MCM-41 has been synthesized in the extremely dense system (with H2O/Si<10) and characterized by XRD, N-2 adsorption isotherm as well as probe reactions of cracking of cumene and isomerization of o-xylene.展开更多
The new crystalline V-Ti-silicalite with mesoporous MCM-41 type molecular sieve structure is synthesized hydrothermally; The framework IR spectra associated with ESR, Si-29 MAS NMR, DRS and XPS data shows that V and T...The new crystalline V-Ti-silicalite with mesoporous MCM-41 type molecular sieve structure is synthesized hydrothermally; The framework IR spectra associated with ESR, Si-29 MAS NMR, DRS and XPS data shows that V and Ti are simultaneously incorporated into V-TiMCM-41 framework.展开更多
A novel environmental friendly catalyst, H3PW12O40/MCM-48, was prepared by impregnation method. The catalysts were characterized by means of XRD and FT-IR. The synthesis of n-butyl methacrylate catalyzed by H3PW12O40/...A novel environmental friendly catalyst, H3PW12O40/MCM-48, was prepared by impregnation method. The catalysts were characterized by means of XRD and FT-IR. The synthesis of n-butyl methacrylate catalyzed by H3PW12O40/MCM-48 was studied with methacrylic acid and n-butyl alcohol as reactants. H3PW12O40/MCM-48 is an excellent catalyst for synthesizing n-butyl methacrylate and Keggin structure of H3PW12O40 kept unchanged after being impregnated on surface of the molecular sieve support. Effects of n（methacrylic acid）：n（n-butyl alcohol）, catalyst dosage, cyclohexane（water-stripped reagent） and reaction time on yields of the product were investigated. The optimum conditions have been found, that is, molar ratio of acid to alcohol is 1：1.6, mass ratio of catalyst used to the reactants is 0.5% and reaction time is 2.0 h. Under these conditions, the yield of n-butyl methacrylate can reach 93.7%.展开更多
The mesoporous molecular sieves MCM-41 were prepared using room tempera-ture ionic liquid （RTIL） synthesized in laboratory and cethytrimethylammonium bromide （CTAB） as compound templates for the first time. They w...The mesoporous molecular sieves MCM-41 were prepared using room tempera-ture ionic liquid （RTIL） synthesized in laboratory and cethytrimethylammonium bromide （CTAB） as compound templates for the first time. They were prepared under low aging temperature and short aging time. Via characterizing by XRD and nitrogen adsorption instrument, MCM-41 synthesized by this new method exhibited good crystal structure and narrow pore distribution. The following pre-paratory conditions was optimal： the molar ratio of RTIL to CTAB was 1.0∶1.0, aging at 80 ℃, for 40 h and calcined at 540 ℃. It is found that the acidified MCM-41 improves its activity as catalyst over the unmodified ones.展开更多
文摘ZSM-5/MCM-41 composite molecular sieve was prepared by the nano-assembling method.The ZSM-5 molecular sieve,the MCM-41 molecular sieve,the ZSM-5/MCM-41 mechanical mixture and the ZSM-5/MCM-41 composite molecular sieve were characterized by X-ray powder diffractometry,N_2 adsorption isotherms,temperature programmed desorption of ammonia and scanning electron microscopy and their properties were analyzed.Using FCC gasoline as the feed,activities of different molecular sieves for reducing olefin content were investigated in a continuous high-pressure micro-reactor unit under the following conditions:a reaction temperature of 400℃,a reaction time of 2 h,a weight hourly space velocity of 3h^(-1),and a reaction pressure of 2.0 MPa.The results showed that the HMCM-41 molecular sieve had low reaction performance,and the HZSM-5 molecular sieve demonstrated high aromatization activity,while the ZSM-5/MCM- 41 composite molecular sieve exhibited a best olefin-reducing performance because of its high isomerization activity and moderate aromatization activity.With a largest olefin-reducmg capability and a reasonable distribution of products,the composite molecular sieve was more suitable for FCC gasoline upgrading compared to other three catalysts.
文摘Mesoporous molecular sieve MCM-41 has been synthesized in the extremely dense system (with H2O/Si<10) and characterized by XRD, N-2 adsorption isotherm as well as probe reactions of cracking of cumene and isomerization of o-xylene.
文摘The new crystalline V-Ti-silicalite with mesoporous MCM-41 type molecular sieve structure is synthesized hydrothermally; The framework IR spectra associated with ESR, Si-29 MAS NMR, DRS and XPS data shows that V and Ti are simultaneously incorporated into V-TiMCM-41 framework.
基金Funded by the Natural Science Foundation of Hubei Province,China(No.2005ABA053)the National Natural ScienceFoundation of China(No.20471044)
文摘A novel environmental friendly catalyst, H3PW12O40/MCM-48, was prepared by impregnation method. The catalysts were characterized by means of XRD and FT-IR. The synthesis of n-butyl methacrylate catalyzed by H3PW12O40/MCM-48 was studied with methacrylic acid and n-butyl alcohol as reactants. H3PW12O40/MCM-48 is an excellent catalyst for synthesizing n-butyl methacrylate and Keggin structure of H3PW12O40 kept unchanged after being impregnated on surface of the molecular sieve support. Effects of n（methacrylic acid）：n（n-butyl alcohol）, catalyst dosage, cyclohexane（water-stripped reagent） and reaction time on yields of the product were investigated. The optimum conditions have been found, that is, molar ratio of acid to alcohol is 1：1.6, mass ratio of catalyst used to the reactants is 0.5% and reaction time is 2.0 h. Under these conditions, the yield of n-butyl methacrylate can reach 93.7%.
基金Funded by Zhengzhou Natural Science Foundation (No. 064SJZJ23115)Key Laboratory Catalysis and Materials Science of Southcentral Universityfor Nationalities Foundation
文摘The mesoporous molecular sieves MCM-41 were prepared using room tempera-ture ionic liquid （RTIL） synthesized in laboratory and cethytrimethylammonium bromide （CTAB） as compound templates for the first time. They were prepared under low aging temperature and short aging time. Via characterizing by XRD and nitrogen adsorption instrument, MCM-41 synthesized by this new method exhibited good crystal structure and narrow pore distribution. The following pre-paratory conditions was optimal： the molar ratio of RTIL to CTAB was 1.0∶1.0, aging at 80 ℃, for 40 h and calcined at 540 ℃. It is found that the acidified MCM-41 improves its activity as catalyst over the unmodified ones.
