纳米尺度高配位活性钛TS-1的制备及性能评价

Preparation of high coordination active titanium nanoscale TS-1 and its catalytic performance evaluation

摘要:

采用低成本模板剂和硅源（四丙基溴化铵和硅溶胶），利用蒸汽辅助干胶晶化法，通过添加晶种的方式合成出纳米级TS-1分子筛。再经二次水热晶化，采用乙胺和四丙基溴化铵的混合溶液对其进行处理，制备出了含有六配位钛的高活性TS-1分子筛。采用X射线衍射、紫外漫反射可见光谱、紫外拉曼光谱、傅里叶变换红外光谱、固体核磁共振、N2物理吸附-脱附等手段对其物理化学性质等进行表征，并考察其对丙烯环氧化反应的催化性能。结果表明，纳米级TS-1分子筛后处理生成了活性更为优异的六配位钛物种，且其孔道结构得到了改善，比表面积明显增大；其催化丙烯环氧化反应的活性明显提高，双氧水转化率由47.59%增至85.79%，有了明显的提升。

Abstract:

Nano-scale TS-1 molecular sieves were synthesized using low-cost reagents (silicasol and tetraprop-ylammonium bromide) by steam-assisted method with assist of seeds. The molecular sieve was post-modified using ethylamine and tetrapropylammonium bromide mixed solution by secondary hydro-thermal crystallization. Then, the TS-1 zeolite with high catalytic activity containing hexacoordinate tita-nium was produced. Then it was characterized by X-ray diffraction, UV diffuse reflectance visible spec-trum, ultraviolet Raman spectroscopy, Fourier transform infrared spectroscopy, solid state nuclear mag-netic resonance, N2 physical adsorption-desorption. Finally, the epoxidation of propylene was used as a probe reaction to evaluate the catalytic performance of the samples. The results showed that the nano-scale TS-1 synthesized by post-modification with hexacoordinate titanium species possessed im-proved pore structure and obviously increased specific surface area. The activity of catalyzing the epoxi-dation of propylene was obviously improved. The conversion rate of hydrogen peroxide was significantly increased from 47.59% to 85.79%.