Phosphotungstic acid loaded on hydrophilic ionic liquid modified SBA-15 for selective oxidation of alcohols with aqueous H₂O₂

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• 作者：Rong Tan^a ; Cheng Liu^a ; Ningdong Feng^b ; Jun Xiao^c ; Weiguo Zheng^a ; Anmin Zheng^b ; Donghong Yin^a ; ^{yindh@hunnu.edu.cn}
• 关键词：Phosphotungstic acid ; Amino-functionalized ionic liquid ; SBA-15 ; Alcohol oxidation ; Aqueous 30%H2O2
• 刊名：Microporous and Mesoporous Materials
• 出版年：2012
• 期刊代码：78_13871811
• 类别：ch
• 出版时间：1 August, 2012
• 卷：158
• 期：Complete
• 页码：77-87
• 文件大小：1987 K

摘要

Phosphotungstic acid (H₃PW₁₂O₄₀) has been successfully loaded onto amino-functionalized ionic liquid modified mesoporous silica SBA-15 by totally anion-exchange and partly protonating in the channel of SBA-15 with Keggin-type H₃PW₁₂O₄₀. XRD patterns, N₂ adsorption-desorption isotherms and TEM images confirm the intact mesostructures of the samples. Thermal analysis, ²⁹Si MAS NMR and ³¹P MAS NMR indicate the presence of the [PW₁₂O₄₀]^{3鈭?/sup> (PW) in the mesopores. FT-IR spectra suggest that a portion of free amino groups in the amino-functionalized IL moiety are remained in the channel of the catalysts, although there are ionic interactions between PW anions and protonated amino groups, as well as between PW anions and imidazolium cations. Hydrophilic amino-functionalized IL moiety in the mesostructures, especially, the remained free amino groups flexibly anchored on the imidazolium, plays a crucial role in enhancing the accessibility of H₂O₂, which in turns significantly improves the catalytic performance. The resultant PW loaded on amino-functionalized IL modified SBA-15 (PW-NH₂-IL-SBA-15) catalysts are proven to be versatile in the solvent-free oxidation of alcohols with aqueous 30%H₂O₂, presenting high efficiency, convenient recovery and steady reuse.}