WO3/SiO2催化剂上2-丁烯与乙烯歧化制丙烯

采用浸渍法制备了WO₃/SiO₂催化剂，对其进行了UV-Vis DRS和NH₃-TPD表征。将WO₃/SiO₂作为催化剂，以乙烯和2-丁烯为原料制备丙烯，考察了反应温度、质量空速等因素对歧化反应的影响。实验结果表明，催化剂的最佳WO₃担载量为8 %；以8%WO₃/SiO₂ 为催化剂，在反应温度473K~573K、压力3.0MPa、质量空速1.6h^-1下，2-丁烯的转化率可保持在80%以上，丙烯的选择性大于89.2%。经过140h的稳定性实验，2-丁烯的转化率和丙烯的选择性略有下降，适当的提高反应温度（由473K增加到513K）可以恢复催化剂的活性。新鲜催化剂表面存在四面体、八面体六价钨物种和体相WO₃，适当还原的W物种是歧化活性物种；W负载在催化剂表面引入了新的强酸中心，同时明显增加了总酸量。

Metathesis of ethylene and 2-butylene to propylene over WO3/SiO2 catalysts

The WO3/SiO2 catalysts were prepared by impregnation(NH4)2WO4 onto SiO2 supports and their physicochemical properties were characterized by means of UV-Vis DRS and NH3-TPD.Effects of reaction conditions on the catalytic performance of WO3/SiO2 for metathesis of ethylene and 2-butylene to produce propylene were investigated.The optimal amount of WO3 loading was ~8%.Under the conditions of 473K~573K,3.0MPa and 1.6h-1,the initial 2-butene conversion was higher than 80% with an exceeding 89.2% selectivity to pr...