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首页> 外文期刊>RSC Advances >Synergistic catalysis within TEMPO-functionalized periodic mesoporous organosilica with bridge imidazolium groups in the aerobic oxidation of alcohols
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Synergistic catalysis within TEMPO-functionalized periodic mesoporous organosilica with bridge imidazolium groups in the aerobic oxidation of alcohols

机译：在节奏官能化的周期性介孔有机体中的协同催化催化剂，具有桥咪唑粒子的有氧氧化醇

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摘要

Anchoring 2,2,6,6-tetramethylpiperidine-1-oxyl radical (TEMPO) within the nanospaces of a periodic mesoporous organosilica with bridged imidazolium groups led to an unprecedented powerful bifunctional catalyst (TEMPO@PMO-IL-Br), which showed enhanced activity in the metal-free aerobic oxidation of alcohols. The catalyst and its precursors were characterized by N-2 adsorption-desorption analysis, transmission electron microscopy (TEM), small angle X-ray scattering (SAXS), thermal gravimetric analysis (TGA), diffuse reflectance infrared Fourier transform spectroscopy (DRIFT), solid state electron paramagnetic resonance (EPR) spectroscopy, elemental analysis, transmission electron microscopy (TEM) and high resolution TEM. It was clearly found that the catalytic activity of SBA-15-functionalized TEMPO (TEMPO@SBA-15) not bearing IL, TEMPO@PMO-IL-Cl, PMO-IL-AMP, or individual catalytic functionalities (PMO-IL/TEMPO@SBA-15) was inferior as compared with those obtained from TEMPO@PMO-IL-Br in the metal-free aerobic oxidation of benzyl alcohol, suggesting the critical role of co-supported TEMPO and imidazolium bromide in obtaining high catalytic activity in the described catalyst system. Our observation clearly points to the fact that the combination of imidazolium bromide units in close proximity to TEMPO moieties in the nanospaces of TEMPO@PMO-IL-Br might be indeed one of the key factors explaining the enhanced catalytic activity observed for this catalyst in the oxidation of benzyl alcohol, possibly through a synergistic catalysis relay pathway. A proposed model was suggested for the observed synergistic effect.
机译：将2,2,6,6-四甲基哌啶-1-氧基自由基（Tempo）与桥接咪唑基团的周期性介孔有机喹硫酮纳米片导致前所未有的强大的双官能催化剂（Tempo @ PMO-IL-BR），其显示出增强无金属有氧氧化醇的活性。通过N-2吸附 - 解吸分析，透射电子显微镜（TEM），小角度X射线散射（SAX），热重分析（TGA），散射反射红外傅里叶变换光谱（漂移），催化剂及其前体特征。固态电子顺磁共振（EPR）光谱，元素分析，透射电子显微镜（TEM）和高分辨率TEM。清楚地发现，SBA-15-官能化速度（TEMPO @ SBA-15）的催化活性未承载IL，TEMPO / PMO-IL-CL，PMO-IL-AMP或个体催化功能（PMO-IL / TEMPO @ SBA-15）与从苯甲醇无金属氧化氧化的TEMPO @ PMO-IL-BR中获得的那些相比，表明共同支持的速度和咪唑溴铵在获得高催化活性方面的关键作用描述了催化剂系统。我们的观察明确指出了氨基吡-MO-BR纳米空间紧密到Tempo M部分紧邻Tempo M部分的事实，这可能是解释在该催化剂中观察到的增强催化活性的关键因素之一苄醇的氧化，可能通过协同催化继电器途径。建议拟议的模型用于观察到的协同效应。

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  • 来源
    《RSC Advances》 |2016年第68期|共7页
  • 作者

    Karimi Babak; Vahdati Saleh; Vali Hojatollah;

  • 作者单位

    Inst Adv Studies Basic Sci Dept Chem POB 45195-1159 Gava Zang 451376731 Zanjan Iran;

    Inst Adv Studies Basic Sci Dept Chem POB 45195-1159 Gava Zang 451376731 Zanjan Iran;

    McGill Univ Facil Electron Microscopy Res Dept Anat &

    Cell Biol Montreal PQ H3A 2A7 Canada;

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  • 正文语种 eng
  • 中图分类 化学;
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