作者：Badusha Mohamad Ali, Ziqi Yu,Zhengyuan Tao,Tangxin Zhang,Lei Wang,Chenbing He,Hao Zhang,Jianli Wang
关键字：Amphiphilic, Janus nanohybrid catalyst, Pickering emulsion, cinnamyl alcohol oxidation, Anelli-Montanari system
论文来源：期刊
具体来源：ACS Applied Materials & Interfaces
发表时间：2024年

新型的2,2,6,6-四甲基哌啶-1-氧基(TEMPO)固定在功能聚合物或纳米颗粒上，作为潜在的皮克林界面催化剂(PICs)，在双相体系中具有有效的催化作用。在本研究中，制备了具有TEMPO锚定纳米杂化颗粒(SM-JPP-TEMPO)的雪人形状的二元结构聚合物，并将其作为潜在的Pickering界面催化剂用于Anelli-Montanari体系中醇的选择性氧化。SM-JPP-TEMPO颗粒的两亲性在皮克林乳液中起着乳化剂和催化剂的双重作用。结果，它使油包水(W/O)界面上的液滴更小(102 μ m)，界面张力从26.58 mN/m降低到17.38 mN/m，从而提高了Pickering乳液体系的稳定性。所构建的Pickering乳液微反应器具有较大的界面接触面积，缩短了肉桂醇底物的传质距离，显著提高了Anelli-Montanari氧化体系的催化转化率，从而在静态(无搅拌)条件下实现了92.3%的转化率和99%的优良选择性。结果表明，与TEMPO接枝球形聚苯乙烯纳米颗粒(PS-NPs-TEMPO)催化剂相比，Janus纳米杂化催化剂(SM-JPP-TEMPO)的催化效率提高了1.29倍(72%)。此外，在连续7个循环后，Janus纳米催化剂(SM-JPP-TEMPO)仍能显著保持转化。因此，这些结果共同强调了两亲性SM-JPP-TEMPO催化剂为强化液-液两相反应系统提供了一种高效且环保的策略，具有潜在的工业应用前景。

The novel 2,2,6,6-tetramethylpiperidine-1-oxyl (TEMPO) groups immobilized on functional polymers or nanoparticles emerged as potential Pickering interfacial catalysts (PICs) for effective catalysis in biphasic systems. In this study, a snowman-shaped Janus-structured polymer with TEMPO-anchored nanohybrid particles (SM-JPP-TEMPO) was prepared and employed as a potential Pickering interfacial catalyst in the Anelli-Montanari system for the selective oxidation of alcohol. The amphiphilic character of SM-JPP-TEMPO particles plays a dual role as an emulsifier and catalyst in Pickering emulsion. As a result, it enables smaller droplets (102 μm) at the water-in-oil (W/O) interface and reduces the interfacial tension from 26.58 to 17.38 mN/m, which develops the stability of the Pickering emulsion system. This constructed Pickering emulsion micro-reactors offers a larger interface contact area and shortens the mass transfer distance of the substrate of cinnamyl alcohol, which significantly enhances the catalytic conversion at the Anelli-Montanari oxidation system, thus achieving remarkable conversion efficiency of (92.3%) with excellent selectivity (99%) in static (stirring-free) condition. It was found that the Janus nanohybrid catalyst (SM-JPP-TEMPO) enhanced 1.29-fold catalytic efficiency compared to the TEMPO grafted spherical polystyrene nanoparticles (PS-NPs-TEMPO) catalyst (72%). Moreover, after seven consecutive cycles, the Janus nanocatalyst (SM-JPP-TEMPO) maintained the conversion significantly. Hence, these results collectively highlight that the amphiphilic SM-JPP-TEMPO catalyst provides an efficient and eco-friendly strategy for the intensification of liquid-liquid biphasic reaction systems for potential applications in industries.

国家自然科学基金(资助号:22178317、22109138)资助。