Preparation of the supported MoO_3 catalyst catalyzed esterification performance research
|School||Changchun University of|
|Keywords||MoO3/SiO2 MoO3/γ-AI2O3 Catalyzed esterification Ethyl acetate Catalyst|
Supported the research papers silica and γ-Al2O3 as the carrier prepared MoO3 catalyst preparation, characterization, and performance of direct esterification of acetic acid with ethanol. High specific surface area of ??SiO2 and γ-Al2O3 as the carrier of ammonium molybdate molybdenum source, volume prepared by impregnation the supported MoO3/SiO2 MoO3/γ-Al2O3 catalyst, characterized by XRD, BET, NH3-TPD by means of the dispersion of the active component of the catalyst on the carrier, the catalyst has a specific surface area and pore structure, N2 adsorption - desorption isotherms, acidic catalyst characterization, and synthesis of ethyl acetate in acetic acid and ethanol as a model reaction , catalytic esterification performance. Impregnation prepared the MoO3/SiO2 catalysts using XRD, BET, NH3-TPD means MoO3/SiO2 catalyst characterization results: the suitability Preparation of MoO3/SiO2, the loading of 20wt%, calcination temperature 450 ℃, calcination time of 4 h, At this point, the conversion of acetic acid was 79.4%, the selectivity of the ethyl acetate to 100%; Suitable ethyl acetate synthesis reaction conditions were: reaction temperature 98 ° C, the molar ratio of acid to alcohol is 1.4:1, reaction time 3h, and the amount of catalyst was 1.9% of the raw materials. XRD analysis showed 20wt% MoO3 close to the theoretical calculated monolayer dispersion threshold SiO2 carrier MoO3 loading, MoO3 highly dispersed amorphous state on the carrier; pore structure analysis shows that MoO3/SiO2 catalyst for The porous structure and a smaller pore size range; NH3-TPD analysis showed that the presence of a weakly acidic active centers MoO3/SiO2 catalyst. Impregnation prepared MoO3/γ-Al2O3 catalyst means of MoO3/γ-Al2O3 catalysts were characterized by XRD, BET, NH3-TPD, results show that: MoO3/γ-Al2O3 appropriate preparation conditions for loading 25wt%, and the calcination temperature was 500 ℃, the calcination time of 4 h, At this point, the conversion of acetic acid was 79.5%, the selectivity of the ethyl acetate to 100%; suitable ethyl acetate synthesis reaction conditions for the reaction temperature is 98 ° C, the acid alcohol molar ratio of 1.4:1, reaction time 3h, 2.4% of the amount of catalyst for the reaction of raw materials. XRD analysis shows that 25wt% MoO3 as load was highly dispersed state on the carrier surface; The hole structure analysis showed MoO3/γ-Al2O3 catalyst having the structure of the single hole, the range of pore distribution in the middle hole; NH3-TPD analysis showed that, MoO3 / Y-Al2O3 catalyst weak acid active center.