摘要
合成了四种金属铜(Ⅱ)-四氮配合物,并用初始速率法研究了25℃时四种配合物催化H2O2氧化偶合2,6-二甲基苯酚生成3,3′,5,5′-四甲基联苯二醌反应的动力学.结果表明此偶合反应符合Michaelis Menten酶催化动力学,并由此获得了反应在不同配合物和不同pH值情况下的动力学参数k2和Km.研究还发现不同的铜配合物其催化活性有不同的最适pH,具有较好电子共轭效应和合适刚柔性结构的铜配合物更有利于反应的进行.对此催化反应的动力学机理研究发现,铜配合物的一级酸式电离中间物种是反应的主要催化活性物种.质谱分析表明,此类铜配合物都能催化2,6-二甲基苯酚进行C-O偶合反应生成不同聚合度的高分子.
Four copper(Ⅱ) complexes were synthesized and the kinetics of oxidative coupling reaction of 2,6-dimethylphenol to 3,3′,5,5′-tetramethyl-4,4′-diphenoquinone with hydrogen peroxide catalyzed by the complexes were studied in Tris-HNO_3 buffer at 25 ℃. The results showed that the catalytic reactions obeyed Michaelis-Menten enzyme-catalysis kinetics and the kinetic parameters k_2 and K_m for different conditions were obtained. The catalytic activity and suitable pH range varied with different copper(Ⅱ) complexes used. The copper(Ⅱ) complexes with both better electron conjugated function and appropriate flexibleness in configuration were in favor of the oxidative coupling reaction. The catalytic mechanism was also investigated and the result showed that the reaction was mainly catalyzed by the first acid ionization species of the copper(Ⅱ) complexes.
出处
《催化学报》
SCIE
EI
CAS
CSCD
北大核心
2005年第4期317-322,共6页
基金
国家自然科学基金资助项目(20107004
20173038).
关键词
铜配合物
2
6-二甲基苯酚
过氧化氢
氧化偶合
动力学
copper complex, 2,6-dimethylphenol, hydrogen peroxide, oxidative coupling, kinetics
