甲苯选择电氟化的性能研究  

Studies on the behavior of selective electro-fluorination of toluene

作　　者：李东东[1] 褚有群[1] 马淳安[1] 

机构地区：[1]浙江工业大学绿色化学合成技术国家重点实验室培育基地,浙江杭州310032

出　　处：《浙江工业大学学报》2011年第5期484-488,共5页Journal of Zhejiang University of Technology

基　　金：国家自然科学基金资助项目(20376074);国家基础研究重大项目前期研究专项基金资助项目(2003CCA01300)

摘　　要：利用循环伏安法和恒电位电解技术研究了甲苯在三乙胺三氟化氢(Et3N.3HF)中的阳极氟化性能,并考察了溶剂(CH3CN)对电极行为的影响.结果表明:甲苯在铂电极上的氟化过程受扩散控制;CH3CN对甲苯在铂电极上的氧化行为具有显著影响,含1mol/L Et3N.3HF的CH3CN溶液具有最强的伏安响应性能,但CH3CN溶液体系的电解过程中阳极表面极易形成不导电的聚合物膜,从而使甲苯的氟化反应无法进行.纯的Et3N.3HF中甲苯在铂电极上的循环伏安曲线具有三个氧化峰;恒电位电解实验证实,甲苯的氟化反应首先发生在甲基上,生成单氟甲基苯和二氟化甲基苯,其后再发生苯环上的氟化.因此,通过控制电极电位在纯Et3N.3HF中可实现甲苯的选择性电氟化.Electrochemical fluorination of toluene in Et3N - 3HF and the effect of solvent （CH3CN） were studied by cyclic voltammetry and potentiostatic electrolysis. The experimental results show that anodic fluorination of toluene is controlled by diffusion step. And the cyclic voltammetric behavior of toluene is greatly dependent on the concentration of Et3N · 3HF in CH3CN. The strongest voltammetric signal is obtained in CH3CN containing 1 mol/L Et3N · 3HF. However, the electrochemical fluorination of toluene is blocked by the insulated polymer film formed rapidly at the Pt anode in the existence of CH3CN. Three oxidative peaks can be found in the voltammetric curves obtained by the oxidation of toluene in neat Et3 N · 3HF. It has been validated that the fluorination of toluene takes place firstly at methyl group to form mono- and di-fluoromethylbenzene at different anodic potentials. Thereafter, fluorination on benzenering occurs. Hereby, selective fluorination of toluene in neat Et3N ·3HF can be achieved by electrolyzing at different anodic potentials.

关 键 词：选择电氟化 甲苯 三乙胺三氟化氢 循环伏安法 

分 类 号：O646[理学—物理化学]