CIESC Journal ›› 2009, Vol. 60 ›› Issue (1): 75-82.
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ZHAO Qinfeng, CHEN Shengli, GAO Jinsen, XU Chunming, LI Dongyu, ZHAO Zhen
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赵秦峰,陈胜利,高金森,徐春明,李东瑜,赵震
Abstract:
Tungsten substituted mesoporous molecular sieves W-SBA-15 catalysts with different Si/W ratios were directly synthesized under hydrothermal conditions by using Na2WO4 as tungsten precursor and tetraethyl orthosilicate(TEOS) as silica precursor.The prepared W-SBA-15 catalysts were characterized by means of XRD, HRTEM, UV-Vis DRS, NH3-TPD and H2-TPR.The characterization data indicated that amorphous tetrahedral and octahedral tungsten species were mainly incorporated into the framework of SBA-15 (Si/W mole ratio of 44), and further increase of the amounts of tungsten species led to the appearance of WO3 in the channels of W-SBA-15 (Si/W mole ratio of 30 and 20).The metathesis catalytic performance of W-SBA-15 catalysts was better than that of the conventional WO3/SiO2 catalysts prepared by impregnation.Under the conditions of 300℃, 3.0 MPa and 6.4 h-1, butene conversion was more than 50% with the propylene selectivity exceeding 96% during the 24 h continuous operation, using W-SBA-15 as the catalyst.The W-SBA-15 with the Si/W mole ratio of 44 exhibited the best dispersion of tungsten species inside the SBA-15 and the best catalytic performance of olefin metathesis among the W-SBA-15 catalysts.
Key words: 歧化, 丙烯, 2-丁烯, 催化剂
摘要:
以Na2WO4为钨源,以正硅酸乙酯为硅源,采用直接水热法合成了W-SBA-15介孔分子筛,并用XRD、N2吸附、HRTEM、UV-Vis DRS、NH3-TPD、H2-TPR等手段对合成的分子筛进行了表征。表征结果表明,当分子筛中硅钨摩尔比为44时,钨物种以高度分散的四面体和八面体形式存在于分子筛的骨架中,随着钨含量的增加,当硅钨比为30时,分子筛中出现了微量的骨架外钨物种,当硅钨摩尔比为20时,骨架外钨含量增多。W-SBA-15分子筛在乙烯与2-丁烯歧化制丙烯反应中表现出优异的催化性能,在反应温度300℃、压力3.0 MPa、质量空速6.4 h-1的实验条件下,反应24 h后丁烯的转化率和丙烯的选择性分别高于50%和96%,优于传统的负载型WO3/SiO2催化剂。硅钨摩尔比为44时的W-SBA-15具有最好的钨物种分散性和最佳的烯烃歧化性能。
关键词: 歧化, 丙烯, 2-丁烯, 催化剂
ZHAO Qinfeng, CHEN Shengli, GAO Jinsen, XU Chunming, LI Dongyu, ZHAO Zhen. Direct synthesis of W-SBA-15 catalysts and their catalytic performance for metathesis of ethylene and 2-butene to propylene[J]. CIESC Journal, 2009, 60(1): 75-82.
赵秦峰, 陈胜利, 高金森, 徐春明, 李东瑜, 赵震. W-SBA-15的直接合成及其对2-丁烯与乙烯歧化制丙烯反应的催化性能 [J]. 化工学报, 2009, 60(1): 75-82.
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