功能化氮氧自由基与MIL-101(Fe)协同催化醇氧化性能

Functional Nitroxide Radicals and MIL-101(Fe) co-Catalysts: Cooperative Catalytic Oxidation of Alcohols

利用酰胺化反应在2,2,6,6-四甲基哌啶-1-氧自由基(TEMPO)分子的4位引入乙酰氨基和异烟酰氨基分别获得Acet-TEMPO和isoNTA-TEMPO分子.将Acet-TEMPO、 isoNTA-TEMPO和TEMPO分别与MIL-101(Fe)组成共催化体系,以苯甲醇选择性氧化为苯甲醛做模型反应,研究上述3种催化体系的催化性能.催化结果表明3种催化体系的催化活性顺序为:MIL-101(Fe)/isoNTA-TEMPO> MIL-101(Fe)/Acet-TEMPO>MIL-101(Fe)/TEMPO.通过对比实验和吸附实验表明isoNTA-TEMPO的吡啶官能团与MIL-101(Fe)的Fe簇配位作用是提高体系催化性能的关键因素.MIL-101(Fe)/isoNTA-TEMPO催化体系对各种芳香醇均表现出较好的催化性能,且催化剂能循环回收利用.

The incorporation of acetylamino and isonicotinamide groups on the p-position of 2,2,6,6-tetramethylpiperidine-1-oxy radical(TEMPO) by amide reaction results in the formation of Acet-TEMPO and isoNTA-TEMPO, respectively. The catalytic activities of the isoNTA-TEMPO, Acet-TEMPO and TEMPO for the oxidation of benzyl alcohol to benzaldehyde were studied by the employments of MIL-101(Fe) as co-catalysts. Our results indicate that the catalytic activities of the three catalysts follow the order of MIL-101(Fe)/isoNTA-TEMPO>MIL-101(Fe)/Acet-TEMPO>MIL-101(Fe)/TEMPO. The control experiments and adsorption experiments indicate that the coordination of isoNTA-TEMPO to the iron clusters of MIL-101(Fe) is a key factor for the superior catalytic activity of the MIL-101(Fe)/iso NTA-TEMPO system. The MIL-101(Fe)/iso NTA-TEMPO also shows good catalytic activity toward the aerobic oxidation of a wide range of aromatic alcohols, and can be reused.