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首页> 外文期刊>Chemistry: A European journal >Acid-Mediated Synthesis of Ordered Mesoporous Aluminosilicates: The Challenge and the Promise
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Acid-Mediated Synthesis of Ordered Mesoporous Aluminosilicates: The Challenge and the Promise

机译：酸介导的有序中孔硅酸盐的合成：挑战和承诺

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摘要

A new intrinsic hydrolysis method was employed, for the first-time, to synthesize well-ordered H-AlSBA-15 with trivalent aluminium exclusively in the tetrahedral framework structure of SBA-15. Unlike other methods, which involve incorporation of aluminium ions in both the framework (Br?nsted) and non-framework (Lewis) sites of the silicate matrix, the intrinsic hydrolysis method isomorphously substitutes aluminium ions in the tetrahedral network even at high aluminium content. This unique approach relies mainly on the hydrolysis rates of the inorganic (silicon and aluminium) precursors used for the preparation in such a way that the condensation occurs simultaneously so as to overcome the usually encountered difficulties in stabilizing aluminium ions in the silicate matrix. In this way, we could successfully synthesize high quality Br?nsted acidic H-AlSBA-15, hitherto not reported. The synthesized materials were systematically characterized by various analytical, spectroscopic, and imaging techniques, including XRD, Brunauer-Emmett-Teller (BET) surface area measurements, TEM, SEM, ~(29)Si and ~(27)Al magic angle spinning NMR spectroscopy, X-ray fluorescence (XRF), and NH_3 temperature-programmed desorption (TPD). The characterization results reveal the presence of a highly porous structure (with narrow pores) and tetrahedrally coordinated trivalent aluminium in the silicate matrix with more medium to strong Br?nsted acid sites. The resulting high quality catalysts exhibit excellent activity for tert-butylation of phenol with high selectivity towards para-tert-butyl phenol and 2,4-di-tert-butyl phenol.
机译：首次采用新的内在水解方法，在SBA-15的四面体框架结构中专门从三价铝中合成具有三价铝的良好有序的H-Alsba-15。与其他方法不同，这涉及在硅酸盐基质的框架（BRαnsted）和非框架（Lewis）位点中掺入铝离子，所以固有的水解方法即使在高铝含量下也使四面体网络中的铝离子替代。这种独特的方法主要依赖于用于制剂的无机（硅和铝）前体的水解速率，使得冷凝同时发生冷凝以克服通常遇到的硅酸盐基质中铝离子的困难。通过这种方式，我们可以成功地合成高质量Br？Nsted酸性H-Alsba-15，迄今未报告。通过各种分析，光谱和成像技术进行系统为特征，包括XRD，Brunauer-Emmett-Teller（Bet）表面积测量，TEM，SEM，〜（29）Si和〜（27）Al Magic角度旋转NMR光谱学，X射线荧光（XRF）和NH_3温度编程解吸（TPD）。表征结果揭示了在硅酸盐基质中的高度多孔结构（具有狭窄的孔）和四面体协调的三价铝，其具有更多的培养基至强Brαnsted酸位点。所得的高质量催化剂表现出优异的苯酚叔丁基化的优异活性，其具有高选择性对比喻 - 叔丁基苯酚和2,4-二叔丁基苯酚的选择性。

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