离子液体中对苯醌的电化学行为

Electrochemical Redox of Benzoquinone in Ionic Liquids

采用循环伏安法（ CV）和现场光谱电化学方法从分子水平上研究了对苯醌（ BQ）在4种离子液体中铂电极上的电化学氧化还原过程.基于在298.15-343.15 K温度范围内对苯醌的伏安曲线，获得了不同温度下对苯醌的扩散系数（D），进而求得其扩散活化能（Ea）.利用现场红外光谱电化学循环伏吸及导数循环伏吸法同时跟踪电化学过程中反应物、中间体及产物随时间（电位）的变化.光谱电化学结果表明，苯醌在1-丁基-3-甲基咪唑四氟硼酸盐（ BMIMBF4）和1-丁基-3-甲基咪唑六氟磷酸盐（ BMIMPF6）中与在乙腈中类似，先生成苯醌阴离子自由基，随后进一步还原为二价阴离子.

The reduction of 1,4-benzoquinone（BQ） on Pt electrode was investigated in various ionic liquids by cyclic voltammetry（CV）. Over a wide range of scan rates, two couples of redox peaks were clearly ob-served in cyclic voltammogram, showing a quasi reversible diffusion process of BQ with the two-step electro-chemical reduction. Diffusion coefficient and activation energy were obtained from cyclic voltammogram, which displayed the increase of diffusion coefficient accompanying temperature rise from 298.15 K to 343.15 K. The techniques of cyclic voltammetry, in situ FTIR spectroelectrochemistry（ FTIR） , cyclic voltabsorptome-try（ CVA ） and derivative cyclic voltabsorptometry （ DCVA ） were used to investigate the electrochemical behavior of BQ in ionic liquids, BMIMBF4 and BMIMPF6 . The results support that BQ undergoes two succes-sive one-electron reductions, corresponding to the formation of a radical anion intermediate and then the dianion, in ionic liquids, while presenting a different shape of cyclic voltammogram compared to anhydrous acetonitrile solvent.