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分别采用直接(ds)和后合成法(ps)合成含铝的介孔分子筛Al(ds or ps)KIT-1。以钛酸四丁酯Ti(OEt)4为钛源,将钛嫁接在AlKIT-1表面制备出Ti-AlKIT-1样品。用傅里叶变换红外光谱、X射线粉末衍射、固体核磁共振(MAS NMR)、固体紫外-可见漫反射光谱(DRS)、能谱(EDS)和N2吸附-脱附对样品进行了表征,并以双氧水氧化环己醇为探针考察了样品的催化活性。实验结果表明,分子筛Ti-AlKIT-1具有规整的介孔孔道结构,钛进入介孔分子筛骨架而成为四配位的骨架钛,铝的存在形式与样品AlKIT-1的预处理有关,经铵溶液洗涤的Al(ds)KIT-1中没有非骨架铝。Ti-AlKIT-1在催化双氧水氧化环己醇反应中铝和钛存在明显的协同作用。样品Ti-Al(ds)KIT-1表现出更高的催化作用,这与其具有较高的比表面积、较大的孔容和较高钛铝比有关,80℃反应48 h,重复使用3次后,环己醇的转化率降低至51.3%,仅下降4.31%。
Al (ds or ps) KIT-1, an aluminum-containing mesoporous molecular sieve, was synthesized by direct (ds) and post-synthesis methods (ps) Ti-AlKIT-1 was prepared by grafting titanium on the surface of AlKIT-1 using Ti (OEt) 4 as a titanium source. The samples were characterized by Fourier transform infrared spectroscopy, X-ray powder diffraction, solid state nuclear magnetic resonance (MAS NMR), solid-state ultraviolet-visible diffuse reflectance spectroscopy (DRS), energy dispersive spectroscopy (EDS) and N2 adsorption-desorption The catalytic activity of the sample was investigated using cyclohexanol as oxidant. The experimental results show that the molecular sieve Ti-AlKIT-1 has a regular mesopore structure, titanium enters the mesoporous framework and becomes a four-coordinated titanium skeleton, and the existing form of aluminum is related to the pretreatment of the sample AlKIT-1. There is no non-framework aluminum in the washed Al (ds) KIT-1. Ti-AlKIT-1 in the catalytic hydrogen peroxide hydrogen peroxide reaction of aluminum and titanium there is a clear synergy. The sample Ti-Al (ds) KIT-1 showed higher catalytic activity, which was related to its higher specific surface area, larger pore volume and higher ratio of titanium to aluminum. The reaction was carried out at 80 ℃ for 48 h and repeated for 3 times After the conversion of cyclohexanol was reduced to 51.3%, only a decrease of 4.31%.