Microporous Carbon and Mesoporous Silica by Use of Twin Polymerization: An Integrated Experimental and Theoretical Approach to Precursor Reactivity
Microporous Carbon and Mesoporous Silica by Use of Twin Polymerization: An Integrated Experimental and Theoretical Approach to Precursor Reactivity
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DOI：
10.1002/cplu.201402029
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发表时间：
2014-07-01
期刊：
影响因子：
3.4
通讯作者：
Mehring, Michael
中科院分区：
文献类型：
--
作者：
Kitschke, Philipp;Auer, Alexander A.;Mehring, Michael
通过Si(OMe)(4)与水杨醇衍生物反应合成了螺环硅醇盐，并通过原位差示扫描量热法研究了双聚合(TP)。热诱导和质子辅助的 TP 都产生了由酚醛树脂和二氧化硅组成的纳米结构杂化材料。碳化和随后用 HF(aq) 处理产生微孔碳，而在空气中氧化则产生介孔二氧化硅。进行 DFT 计算是为了更详细地了解质子辅助 TP 的第一个反应步骤，并支持基于含硅前体（双单体）的空间和电子特征的反应性规模的假设。质子辅助 TP 初始反应步骤的计算反应势垒定性地符合水杨酸酯部分取代基的哈米特常数。该结果提供了一种预测双单体反应性的简单方法。
Spirocyclic silicon alkoxides were synthesized by reaction of Si(OMe)(4) with derivatives of salicylic alcohol and studied by in situ differential scanning calorimetry with regard to twin polymerization (TP). Both, thermally induced and proton-assisted TP gave nanostructured hybrid materials composed of a phenolic resin and silica. Carbonization and subsequent treatment with HF(aq) resulted in microporous carbon, whereas oxidation in air provided mesoporous silica. DFT calculations were performed to obtain a more detailed insight into the first reaction steps of proton-assisted TP and to support the hypothesis of a reactivity scale based on steric and electronic features of the silicon-containing precursors (twin monomers). The calculated reaction barriers for the initial reaction steps of proton-assisted TP are qualitatively in accordance with the Hammett constants of the substituents at the salicylate moiety. This result offers a simple method to predict the reactivity for twin monomers.