ZSM-5 zeolite prepared by a hydrothermal method with the addition of seeds was treated with different concentrations of NaOH.The obtained samples were characterized by XRD,N_2 adsorption,NH_3-TPD,FT-IR,SEM,and studied...ZSM-5 zeolite prepared by a hydrothermal method with the addition of seeds was treated with different concentrations of NaOH.The obtained samples were characterized by XRD,N_2 adsorption,NH_3-TPD,FT-IR,SEM,and studied in the catalytic performance of the hydration of cyclohexene to cyclohexanol.The characterization results showed that with the increase of NaOH concentration,the crystallinity of the treated samples decreased monotonously,and the acid sites of ZSM-5 zeolites first increased and then decreased,while more mesopores formed inside the ZSM-5zeolites.The experimental results of catalytic performance showed that cyclohexene conversion can be improved through introducing the mesopores and enhancing the acidity of ZSM-5 with the NaOH treatment at a low concentration.The highest cyclohexene conversion of 12.8%was obtained when the concentrations of NaOH solution were in the range of 0.2-0.6 mol/L.The selectivity of cyclohexanol on all samples was higher than 99.6%.展开更多
ZSM-5 aggregates consisting of superfine and hierarchical nanocrystals(combined with micropores and intra-crystalline mesopores) with an average size of 30 nm were prepared through one-pot synthesis with the assistanc...ZSM-5 aggregates consisting of superfine and hierarchical nanocrystals(combined with micropores and intra-crystalline mesopores) with an average size of 30 nm were prepared through one-pot synthesis with the assistance of anionic polyacrylamide(APAM). The resultant zeolites(AHN-ZSM-5) were characterized by XRD, ICP-OES, SEM, TEM, BET, NH_3-TPD, Py-IR, and TG analyses and evaluated in the methanol to gasoline(MTG) reaction. Characterization results show that the hierarchical ZSM-5 aggregates possessed two kinds of mesopores, namely inter-and intra-crystalline mesopores. The amount of APAM considerably influenced the mesoporosity and textural properties of AHN-ZSM-5 zeolites. With the addition of APAM in the synthesis, the AHN-ZSM-5 zeolites exhibited large mesopore volume, large external surface area, and appropriate acidity. When applied in the MTG reaction, AHN-ZSM-5 demonstrated a catalytic lifetime that was 1.6 times longer than that of conventional ZSM-5 synthesized in the absence of APAM.展开更多
基金Supported by the National Natural Science Foundation of China (No.21276183)
文摘ZSM-5 zeolite prepared by a hydrothermal method with the addition of seeds was treated with different concentrations of NaOH.The obtained samples were characterized by XRD,N_2 adsorption,NH_3-TPD,FT-IR,SEM,and studied in the catalytic performance of the hydration of cyclohexene to cyclohexanol.The characterization results showed that with the increase of NaOH concentration,the crystallinity of the treated samples decreased monotonously,and the acid sites of ZSM-5 zeolites first increased and then decreased,while more mesopores formed inside the ZSM-5zeolites.The experimental results of catalytic performance showed that cyclohexene conversion can be improved through introducing the mesopores and enhancing the acidity of ZSM-5 with the NaOH treatment at a low concentration.The highest cyclohexene conversion of 12.8%was obtained when the concentrations of NaOH solution were in the range of 0.2-0.6 mol/L.The selectivity of cyclohexanol on all samples was higher than 99.6%.
基金supported by the National Natural Science Foundation of China (No. 21276183)
文摘ZSM-5 aggregates consisting of superfine and hierarchical nanocrystals(combined with micropores and intra-crystalline mesopores) with an average size of 30 nm were prepared through one-pot synthesis with the assistance of anionic polyacrylamide(APAM). The resultant zeolites(AHN-ZSM-5) were characterized by XRD, ICP-OES, SEM, TEM, BET, NH_3-TPD, Py-IR, and TG analyses and evaluated in the methanol to gasoline(MTG) reaction. Characterization results show that the hierarchical ZSM-5 aggregates possessed two kinds of mesopores, namely inter-and intra-crystalline mesopores. The amount of APAM considerably influenced the mesoporosity and textural properties of AHN-ZSM-5 zeolites. With the addition of APAM in the synthesis, the AHN-ZSM-5 zeolites exhibited large mesopore volume, large external surface area, and appropriate acidity. When applied in the MTG reaction, AHN-ZSM-5 demonstrated a catalytic lifetime that was 1.6 times longer than that of conventional ZSM-5 synthesized in the absence of APAM.
