Ag^(2+)与乙酸的化学反应动力学

Reaction Kinetics Between Ag^(2+) and Acetic Acid in Nitric Acid Medium

采用分光光度法研究了硝酸介质中Ag2+与乙酸(HAc)的化学反应动力学。考察了HAc浓度、酸度、NO3-浓度和温度对Ag2+氧化HAc的影响。结果表明:提高HAc浓度、Ag2+浓度、温度和降低酸度均有利于加快Ag2+与乙酸的反应速率,而NO3-对反应速率的影响不大。得到的反应动力学方程为:-dc(Ag2+)/dt=kc(Ag2+)c(HAc)c-1(H+),25℃时,反应的速率常数为(610±15)(mol/L)-1·min-1,反应活化能Ea=(48.8±3.5)kJ·mol-1。

The reaction kinetics between Ag2＋ and acetic acid in nitric acid medium was studied by spectrophotometry. The effects of concentrations of acetic acid （HAc）, H＋, NO3- and temperature on the reaction were investigated, and the rate equation and the corresponding parameters were obtained. The rate equation is determined as follows： -dc（Ag2＋）/dt= kc（Ag2＋）c（HAc）c-1（H＋）, where the rate constant is （610？15） （mol/L）-1？min-1 at 25 ℃, and the activation energy is （48.8±3.5） kJ？mol-1. The reduction rate of Ag2＋ can be improved by either increasing the HAc concentration and the temperature, or decreasing the concentration of nitric acid. However, the effect of concentration of NO3- on the reduction rate of Ag2＋ is negligible.