Magnetically Separable Single-Site Ti鈥揊e3O4@MCM-41 Catalyst for Selective Epoxidation of Olefins

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• 作者：Ajay Jha ; Chetana R. Patil ; Ajit C. Garade ; Chandrashekhar V. Rode
• 刊名：Industrial & Engineering Chemistry Research
• 出版年：2013
• 出版时间：July 24, 2013
• 年：2013
• 卷：52
• 期：29
• 页码：9803-9811
• 全文大小：499K
• 年卷期：v.52,no.29(July 24, 2013)
• ISSN：1520-5045

文摘

Magnetically separable Ti鈥揊e₃O₄@MCM-41 (Ti-MS) catalysts were prepared by postgrafting Ti with varying loading on mesoporous silica containing dispersed magnetite. The hexagonal structure of Ti-MS catalysts with a periodicity in the pores and a highly ordered hexagonal matrix was established by X-ray diffraction and transmission electron microscopy, while diffuse reflectance UV showed the isolated tetrahedral Ti species coordinated with O^{2鈥?/sup>. From the Fourier transform infrared studies, the extent of Ti鈥揙鈥揝i linkage was found to increase with increase in Ti-loading from 1 to 5 wt % beyond which (10%), the intensity of Ti鈥揙鈥揝i band decreased due to the polymerization of the Ti on the silica surface. Silanol groups on the surface of silica interact with the precursor Ti(OiPr)₄ to give site isolated tetrahedral Ti-species responsible for complete selectivity to the epoxide in the epoxidation of cyclooctene. The magnetic property facilitated easy recovery of the catalyst for its successful eight recycles showing its stability under reaction conditions.}