在HNO3溶液中研究了N,N-二甲基羟基胺(DMHA)与V(Ⅴ)氧化还原反应动力学.通过考察溶液酸度、还原剂浓度、离子强度和温度等因素对反应过程的影响，获得动力学速率方程为-d[V(Ⅴ)]/dt=k[V(Ⅴ)][DMHA]，在25.2℃，μ=0.976mol/L时，反应速率常数k=(9.95±1.0)L2/(mol2.s)；反应活化能ΔE=22.1kJ/mol；依据氮氧自由基的ESR波谱推测了可能的反应机理.
The kinetics and mechanism of the redox reaction betweenN,N-dimethylhydroxylamine(DMHA) and vanadium(Ⅴ) in nitric acid medium at 25.2 ℃ have been studied by spectrophotometry. By investigating the influences of the DMHA concentration, solutio acidity and reaction temperature on the reaction, the reaction rate equation is found to be -d[V(Ⅴ)]/dt=k[V(Ⅴ)][DMHA] where the k is calculated to be (9.95±1.0) L2/(mol2.s), ΔE=22.1 kJ/mol under experiment conditions.A single-electron transfer mechanism has been suggested based on the ESR results of (CH3)2N.O radical. The following reaction is the rate controlling step: [HO—V—O…H…O—N(CH3)2]2+→ (CH3)2O+H2O+VO2+
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