Synthesis and bifunctional catalysis of metal nanoparticle-loaded periodic mesoporous organosilicas modified with amino groups
Synthesis and bifunctional catalysis of metal nanoparticle-loaded periodic mesoporous organosilicas modified with amino groups
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DOI：
10.1039/c5ra13090e
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发表时间：
2015-08
期刊：
影响因子：
3.9
通讯作者：
Y. Horiuchi;Dang Do Van;Y. Yonezawa;Masakazu Saito;S. Dohshi;Tae-Ho Kim;M. Matsuoka
中科院分区：
文献类型：
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作者：
Y. Horiuchi;Dang Do Van;Y. Yonezawa;Masakazu Saito;S. Dohshi;Tae-Ho Kim;M. Matsuoka
本文介绍了一种周期性介孔有机硅（PMO）为基础的双功能催化剂，包括氧化和碱催化活性的发展。选择周期性介孔乙烯二氧化硅（PME）作为催化剂载体，并通过桥连乙烯部分的环氧化和随后的亲核加成以构建碱基位点用乙二胺进行改性。FT-IR测量所得的材料，PME-ED，揭示了氨基基团的成功引入到桥接乙烯部分。PME-ED作为固体碱催化剂，可促进苯甲醛与各种活泼亚甲基化合物的Knoevenagel缩合反应。该催化体系中活性亚甲基化合物的适用范围显示了PME-ED的碱强度，其中质子可以从丙二酸二乙酯（pKa：16.4）而不是从苄基氰（pKa：21.9）中提取。此外，双功能催化性能的产生，以促进一锅串联反应组成的醇的氧化和Knoevenagel缩合是实现通过负载的Au纳米粒子内PME-ED。这种催化剂的设计方法也可以扩展到开发另一种双功能催化剂，这是由Pd纳米粒子和PME修饰的N，N-二甲基乙二胺，以促进Tsuji-Trost反应。
The present article describes the development of a periodic mesoporous organosilica (PMO)-based bifunctional catalyst that includes both oxidative and base catalytic activities. Periodic mesoporous ethylenesilica (PME) was selected as a catalyst support and modified with ethylenediamine through epoxidation of bridging ethylene moieties and the following nucleophilic addition in order to construct base sites. FT-IR measurements for the resulting material, PME-ED, reveal the successful introduction of amino groups into the bridging ethylene moieties. PME-ED can promote Knoevenagel condensation between benzaldehyde and various active methylene compounds as a solid base catalyst. The scope of applicable active methylene compounds in this catalytic system shows the base strength of PME-ED, in which a proton can be abstracted from diethyl malonate (pKa: 16.4) but not from benzyl cyanide (pKa: 21.9). Moreover, the generation of bifunctional catalytic properties to promote a one-pot tandem reaction consisting of alcohol oxidation and Knoevenagel condensation is realised by loading of Au nanoparticles within PME-ED. This catalyst design methodology can be also extended to developing another bifunctional catalyst that is composed of Pd nanoparticles and PME modified with N,N-dimethylethylenediamine in order to promote a Tsuji–Trost reaction.