计时电量法测定4,5-二氮芴-9-酮的扩散系数和反应速率常数

Determination of 4,5-Diazafluorene-9-One Diffusion Coefficients and Rate Constants by Chronocoulometry

摘要: 运用循环伏安法测定4，5-二氮芴-9-酮（DAFO）在DMF溶液中不同扫描速率时的循环伏安图，出现2对峰形良好的氧化还原峰；采用计时电量法通过控制阶跃电位，测得不同温度下DAFO在DMF溶液中的扩散系数和反应速率常数，293K时扩散系数为5.39×10^-6cm²·s^-1；当选择阶跃电位使电极过程处于扩散和电化学混合控制时，测得不同电位的反应速率常数k_f. 根据不同温度下的标准速率常数k₀，得到表观活化能E_a为10.5kJ·mol^-1.

Abstract: The effect of scan rate on the electrochemical behavior of 4,5-diazafluorene-9-one (DAFO) in DMF solution was studied using cyclic voltammetry method and two pairs of good redox peak were observed. Chronocoulometry was applied to determine the diffusion coefficients and the rate constants (k_f and k₀) of DAFO at different temperatures. The diffusion coefficient was 5.39×10^-6cm²·s^-1 at 293K. The forward rate constants (k_f) at different potentials were obtained when the electrode process was controlled by diffusion and electrochemistry. According to the standard rate constants (k₀), the activation energy (E_a) of the electron transfer could be calculated as 10.5kJ·mol^-1.