作者：Hao Zhang, Zhengyuan Tao, Ziqi Yu, Tiantian Zhu, Hanlin Rao, Badusha Mohamad Ali, Jianli Wang
关键字：Janus particles,TEMPO, Pickering interfacial catalyst, Alcohol oxidation, Biphasic reactions
论文来源：期刊
具体来源：Surfaces and Interfaces
发表时间：2024年

  Pickering界面催化剂（Pickering interface catalyst, PICs）作为一种同时增强和催化液-液两相反应的有前景的解决方案而出现。在这项研究中，我们成功地合成了哑铃形状的Janus结构聚合物纳米颗粒，其中一侧锚定咪唑-TEMPO（im-C₄-TEMPO@JPP）作为醇氧化的Pickering界面催化剂，使用Anelli-Montanari反应体系。在Pickering乳液体系中，由于咪唑-TEMPO锚定叶的亲水性，im-C₄-TEMPO@JPPs颗粒聚集在W/O界面上，这使得聚合物Janus哑铃具有优异的两亲性。此外，im-C₄-TEMPO@JPPs颗粒使界面张力从27.82 mN/m降低到18.43 mN/m。im-C₄-TEMPO@JPPs优异的界面吸附能力使水/二氯甲烷Pickering乳状液（乳状液体积分数＞90 %）具有2个月以上的强稳定性，为液-液两相反应提供了高效的反应平台。结果表明，所构建的皮克林乳液体系在静态条件下能有效地催化肉桂醇氧化为肉桂醛。反应1小时后，肉桂醇的转化率达到97.1%，选择性为99%，与搅拌强化双相反应基本相同。因此，这种新型PIC有效地提高了液-液两相催化反应的效率和可持续性。

Pickering interfacial catalysts (PICs) have emerged as a promising solution for simultaneously enhancing and catalyzing liquid-liquid biphasic reactions. In this study, we successfully synthesized dumbbell-shaped Janus structured polymeric nanoparticles with one side anchored imidazolium-TEMPO (im-C4-TEMPO@JPP) as Pickering interfacial catalyst for the oxidation of alcohols using the Anelli-Montanari reaction system. In the Pickering emulsion system, the im-C4-TEMPO@JPPs particles are assembled at the W/O interface due to the hydrophilicity of imidazolium-TEMPO anchored lobe which enables excellent amphiphilic character of the polymeric Janus dumbbell. Moreover, the im-C4-TEMPO@JPPs particles reduce the interfacial tension from 27.82 to 18.43 mN/m. This excellent interfacial adsorption capacity of im-C4-TEMPO@JPPs strongly stabilizes the water/dichloromethane Pickering emulsion over two months (emulsion volume fraction >90 %), thus providing an efficient reaction platform for liquid-liquid biphasic reactions. As a result, the constructed Pickering emulsion system efficiently catalyzes the oxidation of cinnamyl alcohol to cinnamaldehyde under static conditions. After 1 hour of reaction, the conversion of cinnamyl alcohol achieved 97.1 % with a selectivity of 99 %, nearly the same level relative to stirring intensified biphasic reaction. Hence, this novel PIC effectively improves the efficiency and sustainability of liquid-liquid biphasic catalytic reactions.

国家自然科学基金(资助号:22178317、22109138)资助。