碱性介质中二(碲酸根)合铜(Ⅲ)酸根氧化乙二醇一乙醚的反应动力学及机理

摘要

在碱性介质中用分光光度法研究了二过碲酸合铜(Ⅲ)配离子(DTC)氧化乙二醇一乙醚(EGE)的反应动力学及机理.反应速率表明:反应对DTC为准一级,对EGE为分数级;在保持准一级条件([EGE]>[DTC])下,表观速率常数随着OH-浓度的增加而增大,随着TeO2-浓度的增加而减小;有负的盐效应.据此提出了包括配离子和EGE形成络合物的前期平衡的反应机理,由假设反应机理推出的速率方程能很好的解释全部实验现象,进一步求得速控步的速率常数和活化参数.%The kinetics of the oxidation of ethylene glycol monoethyl ether (EGE) by di telluratocuprate (Ⅲ) complexrn(DTC) was studied in alkaline medium with spectrophotometry. The reaction rate showed pseudo-first order de-rnpendence in oxdation and fractional order in EGE. It was found that the pseudo-first order(under the condition:rn[EGE]》[DTC] ) rate constants kobs increased with the increase in [OH- ] and decrease in [TeO42- ]. There is arnnegative salt effect. A mechanism involving a preequilibrium of a adduct formation between the complex and EGErnwas proposed. The rate equation derived from the mechanism can explain all the experimental results. The acti-rnvation parameters along with the rate constants of the rate-determining step were calculated.