二羟基二高碘酸合镍(Ⅳ)配离子氧化异丙醇的反应动力学及机理  

Kinetics and Mechanism of Oxidation of Isopropyl Alcohol by Dihydroxydiperiodatonickelate(Ⅳ) Complex Ion

作　　者：宋文玉[1] 张良苗[1] 白素英[1] 

机构地区：[1]河北大学化学与环境科学学院,河北保定071002

出　　处：《河北大学学报（自然科学版）》2002年第4期351-355,共5页Journal of Hebei University(Natural Science Edition)

摘　　要：在碱性介质中用分光光度法研究了二羟基二高碘酸合镍 (Ⅳ )配离子 (DDN)于 2 5～ 4 0℃区间氧化异丙醇的反应动力学 .结果表明 ,反应对DDN为一级 ,对异丙醇为正分数级 .准一级速率常数kobs随[OH- ]增大而增大 ,随 [IO4 - ]增大而减小 .有微弱的正盐效应 ,未检出自由基 .提出一个包括Ni(Ⅳ )和异丙醇生成加合物前期平衡的反应机理 ,导出的速率方程满意地解释了所有的实验事实 ,并计算出平衡常数、速控步骤的速率常数及相应的活化参数 .The kinetics of oxidation of isopropyl alcohol by dihydroxydiperiodatonickelate(Ⅳ) complex ion was studied by spectrophotometry in aqueous alkaline medium in a temperature range of 25 ～ 40 ℃ .The reaction rate showed first order dependence in oxidant, and positive fractional order dependence in isopropyl alcohol. It was found that the pseudo first order ([(CH_3)_2CHOH] ) rate constant k_ obs increases with the increase of and decreases with the increases of . A weak positive ionic strength effect was observed. Under the protection of nitrogen the reaction system does not induce polymerization of acrylamide indicating that an innersphere one_step two_election transfer is involved in the oxidation. A reasonable mechanism involving a preequilibrium of an adduct formation between Ni(Ⅳ) and isopropyl alcohol has been proposed. The rate equations derived from the mechanism explained all the experimental results satisfactorily and the preequilibrium constants, rate constants of the rate_determining step together with the parameters were evaluated.

关 键 词：反应动力学 二羟基二高碘酸合镍 异丙醇 氧化还原反应 反应机理 平衡常数 速率常数 

分 类 号：O623.411[理学—有机化学] O64[理学—化学]