论文部分内容阅读
采用浸渍法制备了一系列钨负载量不同的W/Si O2/Al2O3催化剂.采用X射线衍射(XRD)、激光拉曼(Raman)光谱、紫外-可见(UV-Vis)光谱、氢气程序升温还原(H2-TPR)和氨程序升温脱附(NH3-TPD)等技术对催化剂进行了表征.实验结果表明:钨的负载量对催化剂上氧化钨物种的分散程度、还原性以及催化剂的酸性有非常重要的影响.对该类催化剂上1-丁烯自歧化反应进行了详细考察,结果表明:当钨的质量分数为6.0%时,W/Si O2/Al2O3催化剂表现出最佳的歧化活性和稳定性.原因在于6.0%的钨负载量可以使催化剂上氧化钨物种具有中等程度的分散性、合适的还原性,并且使催化剂具有一定程度的酸性,这些因素有利于在催化剂上形成烯烃歧化活性位.
A series of W / Si O2 / Al2O3 catalysts with different loadings of tungsten were prepared by impregnation method.With XRD, Raman spectroscopy, UV-Vis spectroscopy and hydrogen temperature programmed reduction (H2-TPR) and ammonia temperature-programmed desorption (NH3-TPD) were used to characterize the catalyst.The experimental results show that the loading of tungsten has a great influence on the dispersion, reducibility of the tungsten oxide species on the catalyst and the acidity of the catalyst The results showed that the W / Si O2 / Al2O3 catalyst exhibited the best disproportionation activity and stability when the mass fraction of tungsten was 6.0% The reason is that a tungsten loading of 6.0% gives a moderate degree of dispersibility, proper reducibility, and a certain degree of acidity to the tungsten oxide species on the catalyst, which facilitates the formation of olefin disproportionation active sites on the catalyst .