Direct synthesis of mesoporous CrSBA-15 catalyst and its high activity and selectivity for oxidation of anthracene

作者：Selvaraj M; Kawi S^*

来源：Microporous and Mesoporous Materials, 2007, 101(1-2): 240-249.

DOI：10.1016/j.micromeso.2006.12.020

• mesoporous materials
• CrSBA-15
• selective oxidation
• anthracene
• 9,10-anthraquinone

Mesoporous CrSBA-15 molecular sieves with different n(Si)/n(Cr) ratios have been directly synthesized, for the first time, using Pluronic 123 triblock polymer [(EO)(20)(PO)(70)(EO)(20)] as a structure-directing agent by NH(4)F acidic method and pH-adjusting method. The mesoporous materials have been characterized using ICP-AES, XRD, N(2) adsorption, ESR, SEM and TEM. ICP-AES studies show a higher amount of chromium incorporation on the silica pore walls in pH-adjusting method as compared to NH(4)F acidic method; however, more octahedral Cr(3+) species are oxidised using pH-adjusting method than those using NH(4)F acidic method. The structural and textural properties of calcined CrSBA-15 are characterized by XRD and N(2) adsorption. ESR results show that both octahedral Cr(3+) and tetrahedral Cr(5+)/Cr(6+) are coordinated on the silica surface of calcined CrSBA-15 prepared using NH(4)F acidic method whereas only tetrahedral Cr(5+)/Cr(6+) are coordinated on the silica surface of calcined CrSBA-15 prepared using pH-adjusting method. TEM and FE-SEM images show the uniform pore diameter and rope-like hexagonal mesoporous structure of CrSBA-15. CrSBA-15 materials have then been used as catalysts for liquid-phase oxidation of anthracene for selective synthesis of 9,10-anthraquinone under different optimal conditions using benzene as the solvent and t-BHP as the oxidant. CrSBA-15(4) gave the highest conversion of 90.6% of anthracene and 100% selectivity of anthraquinone as compared to other CrSBA-15 and CrMCM-41 catalysts.

• 出版日期2007-4-19