微-介孔Hβ沸石负载三氟甲烷磺酸催化异丁烷/2-丁烯的烷基化反应

Alkylation of Iobutanes/2-Butene Catalyzed by Meso-microporous HβZeolites Loaded with Trifluoromethanesulfonic Acid

通过碱处理对β沸石进行脱硅扩孔,制备成氢型后负载不同质量的三氟甲烷磺酸(TfOH),用于催化异丁烷与2-丁烯的烷基化反应。扩孔后Hβ沸石的微-介孔结构,有利于延长催化剂的使用寿命;TfOH的负载可以适当提高催化剂B/L酸性位点的比例,有利于提高烷基化产物的选择性。对改性后的催化剂进行了X射线荧光光谱分析、粉末X射线衍射、N2吸附脱附等温线、吡啶红外光谱、NH3-TPD等分析或表征。以固定床反应器,通过连续进样的方式探究了不同TfOH负载量的催化剂及反应条件对异丁烷/2-丁烯烷基化反应性能的影响。当TfOH的负载量占β沸石质量的20%,催化效果最佳。在反应温度80℃,反应压力2.5MPa,烯烃质量空速0.8h^(-1)的优化条件下,催化剂有更长的寿命而且烯烃有较高的转化率,C8产物的选择性保持在65%以上。

By desilicating in alkaline solution,cation exchanging,and loading of trifluoromethanesulfonic acid(TfOH),meso-microporous Hβzeolite catalyst was prepared and used to catalyze the alkylation of isobutane and cis-2-butene.After pore expansion,the hierarchical pore structure of Hβzeolite is beneficial to prolong the lifetime of the catalyst;the loading of TfOH can appropriately increase the ratio of B/L acid sites in the catalyst,which is beneficial to increase the selectivity of alkylation products.The modified catalyst was analyzed or characterized by X-ray fluorescence spectroscopy,powder X-ray diffraction,N2 adsorption and desorption isotherm,pyridine infrared spectrum,and NH3-TPD.Using a fixed bed as a reactor,the effects of catalysts with different amounts of TfOH loading and reaction conditions on the catalytic performance of isobutane/2-butene alkylation were investigated by continuous sample injection.When the loading of TfOH accounts for 20%of the mass ofβzeolite,the catalyst shows the best performance.Under the optimized conditions of reaction temperature of 80℃,reaction pressure of 2.5 MPa,and the weight hourly space velocity(WHSV)of 0.8 h^(-1),a high olefin conversion can be maintained for a long time,and the selectivity of C8 products can be maintained above 65%.