聚醚桥连二异羟肟酸双核配合物催化PNPP水解的反应动力学  

Kinetics of PNPP Hydrolysis Catalyzed by Polyether-Bridged Dihydroxamic Acid Transition-Metal Complexes

作　　者：黄生田[1,2] 李建章[1,2] 刘富安[1] 周波[3] 冯发美[1] 秦圣英[3] 

机构地区：[1]四川理工学院化学系 [2]四川大学化学学院,四川成都610064 [3]四川大学化学学院

出　　处：《催化学报》2005年第1期43-48,共6页

基　　金：国家自然科学基金资助项目 (2 0 0 72 0 2 5 );四川省教育厅重点科研项目 (2 0 0 3A182 )

摘　　要：合成了 4种聚醚桥连二异羟肟酸双核配合物 ,并将其用于催化α 吡啶甲酸对硝基苯酯 (PNPP)水解反应 ,研究了聚醚桥连二异羟肟酸双核配合物催化PNPP水解反应的动力学和机理 ,提出了配合物催化PNPP水解的动力学模型 .结果表明 ,在2 5℃条件下 ,随着缓冲溶液pH值的增大 ,聚醚桥连二异羟肟酸双核配合物催化PNPP水解速率逐渐提高 ,表现出很高的催化活性 .根据阿累尼乌斯公式和不同温度下的表观一级常数 ,求出了水解反应的表观活化能 .Four polyether-bridged dihydroxamic acid transition-metal complexes were synthesized and used as catalysts for hydrolysis of p-nitrophenyl picolinate (PNPP). The reaction kinetics and the reaction mechanism of the PNPP hydrolysis were investigated. The kinetic mathematical model of hydrolysis was proposed. The results showed that the rate for the PNPP hydrolysis catalyzed by the complexes was increased as the increase of pH from 7.0 to 8.2 and these complexes exhibited high activity for the reaction. The catalytic activity of different metal ions decreased in the order Cu2+ > Zn2+ > Co2+ > Mn2+. The pseudo-first-order rate constants of PNPP hydrolysis catalyzed by the complexes were 4.36 X 10(2) similar to 1.12 X 10(4) times as large as that of spontaneous hydrolysis of PNPP at pH = 7.0 and [S] = 0.20 mmol/L. The apparent activation energy of the PNPP hydrolysis was calculated according to the Arrhenius equation and the pseudo-first-order rate constants at temperature ranged 15similar to65 degreesC. The apparent activation energy of the catalytic hydrolysis followed the order Mn2L2 > Co2L2 > Zn2L2 > Cu2L2. The results also indicated that the four complexes were stable in the temperature range and the acidity range investigated.

关 键 词：聚醚桥连二异羟肟酸 过渡金属配合物 α-吡啶甲酸对硝基苯酯 水解 反应动力学 

分 类 号：O643.3[理学—物理化学]