金属铜配合物催化氧化1-(3,4-二甲氧基苯)乙醇的动力学研究

Kinetic Study on Oxidation of 1-(3,4-Dimethoxyphenyl)ethanol Catalyzed by Copper(Ⅱ) Complexes

合成了1-(3,4-二甲氧基苯)乙醇(DMPE)作为木质素模型物,并用初始速率法研究了40℃时在pH6.5～8.5磷酸缓冲溶液中N,N-双(2-乙基-5-甲基-咪唑-4-亚甲基)乙醇胺合铜、N,N-双(2-(2-羟乙基胺基)乙基)草酰胺合铜和5,7,12,14-四甲基-1,4,8,11-四氮杂环十四-4,7,11,14-四烯合铜催化氧化1-(3,4-二甲氧基苯)乙醇的动力学,提出了1-(3,4-二甲氧基苯)乙醇氧化反应动力学模型,并由此计算出不同pH值条件下催化反应动力学参数k2和Km.铜配合物的催化活性随着pH的增大而增大.具有大共轭体系的配体催化剂表现出更好的催化活性.提出并讨论了H2O2氧化DMPE的催化氧化反应机理.

1-（3,4-Dimethoxyphenyl）ethanol （DMPE） was synthesized and used as the model of lignin.Kinetics of the reaction of DMPE with hydrogen peroxide catalyzed by three copper（Ⅱ） complexes was studied in phosphoric acid buffer solution at 40 ℃.A kinetic model of catalytic oxidation of DMPE was suggested,and the kinetic parameters k 2 and K m under different conditions were obtained.The catalytic efficiency of the copper（Ⅱ） complexes increased with increasing pH.The complex with the electron conjugated ligand showed the best catalytic activity on the oxidation reaction.A possible catalytic mechanism of the oxidation of DMPE was proposed and discussed in detail.