We report herein an experimental study on the development of basicity on mesoporous silicas and metallosilicates (Nb- and Ce-) on SBA-15 and MCF porous structures. Our results demonstrated that the role of the catalyst structure (hexagonally ordered mesoporous SBA-15 vs. mesoporous cellular foam MCF), the effect of the amount and nature of metal in the supports (different acidic/redox properties), and the effect of the type of nitrogen-containing organic modifier (imidazole, triazole and aminotriazole) play an important role on the activity and selectivity in Knoevenagel condensation, which is a well-known probe reaction to determine the basicity of inorganic solids. We demonstrate that niobium Lewis acidity is determinant for the Knoevenagel condensation and, also, redox properties of cerium play an important role in the basicity. In fact, acid–base cooperation plays a positive role in promoting the Knoevenagel condensation via the ion-pair mechanism. These mesoporous silicas and metallosilicates are interesting catalysts for production of fine chemicals due to their thermal stability and controllable acid–base catalytic properties.

中文翻译：

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介孔二氧化硅和金属硅酸盐的碱度发展

我们在这里报告了对SBA-15和MCF多孔结构上的介孔二氧化硅和金属硅酸盐（Nb-和Ce-）的碱度发展的实验研究。我们的结果证明了催化剂结构的作用（六角有序介孔SBA-15与介孔泡沫（MCF），载体中金属的数量和性质的影响（不同的酸性/氧化还原特性）以及含氮有机改性剂（咪唑，三唑和氨基三唑）类型的影响在​​以下方面起着重要作用Knoevenagel缩合反应的活性和选择性，这是确定无机固体碱度的众所周知的探针反应。我们证明铌路易斯酸度是Knoevenagel缩合反应的决定因素，而且铈的氧化还原性质在碱度中也起重要作用。实际上，酸碱合作通过促进Knoevenagel缩合反应起着积极作用。离子对机制。这些中孔二氧化硅和金属硅酸盐因其热稳定性和可控的酸碱催化性能而成为生产精细化学品的有趣催化剂。