TEMPO-Grafted Polystyrene/Polymethacrylate Organosiloxane Janus Nanohybrids as Efficient Pickering Interfacial Catalyst for Selective Aerobic Oxidation of Cinnamyl Alcohol
writer：Badusha Mohamad Ali, Ziqi Yu,Zhengyuan Tao,Tangxin Zhang,Lei Wang,Chenbing He,Hao Zhang,Jianli Wang
keywords：Amphiphilic, Janus nanohybrid catalyst, Pickering emulsion, cinnamyl alcohol oxidation, Anelli-Montanari system
source：期刊
specific source：ACS Applied Materials & Interfaces
Issue time：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納米顆粒上，作為潛在的皮克林界面催化劑(PICs)，在雙相體系中具有有效的催化作用。在本研究中，制備了具有TEMPO錨定納米雜化顆粒(SM-JPP-TEMPO)的雪人形狀的二元結(jié)構(gòu)聚合物，并將其作為潛在的Pickering界面催化劑用于Anelli-Montanari體系中醇的選擇性氧化。SM-JPP-TEMPO顆粒的兩親性在皮克林乳液中起著乳化劑和催化劑的雙重作用。結(jié)果，它使油包水(W/O)界面上的液滴更小(102 μ m)，界面張力從26.58 mN/m降低到17.38 mN/m，從而提高了Pickering乳液體系的穩(wěn)定性。所構(gòu)建的Pickering乳液微反應器具有較大的界面接觸面積，縮短了肉桂醇底物的傳質(zhì)距離，顯著提高了Anelli-Montanari氧化體系的催化轉(zhuǎn)化率，從而在靜態(tài)(無攪拌)條件下實現(xiàn)了92.3%的轉(zhuǎn)化率和99%的優(yōu)良選擇性。結(jié)果表明，與TEMPO接枝球形聚苯乙烯納米顆粒(PS-NPs-TEMPO)催化劑相比，Janus納米雜化催化劑(SM-JPP-TEMPO)的催化效率提高了1.29倍(72%)。此外，在連續(xù)7個循環(huán)后，Janus納米催化劑(SM-JPP-TEMPO)仍能顯著保持轉(zhuǎn)化。因此，這些結(jié)果共同強調(diào)了兩親性SM-JPP-TEMPO催化劑為強化液-液兩相反應系統(tǒng)提供了一種高效且環(huán)保的策略，具有潛在的工業(yè)應用前景。
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.
國家自然科學基金(資助號:22178317、22109138)資助。