甲基磺酰氟Simons电化学氟化过程特性和机理研究
收稿日期: 2016-10-26
修回日期: 2017-05-20
网络出版日期: 2017-05-20
基金资助
国家自然科学基金项目（21076173）资助
Characteristics and Mechanism for the Simons Electrochemical Fluorination of Methanesulfonyl Fluoride
Received date: 2016-10-26
Revised date: 2017-05-20
Online published: 2017-05-20
选择CH3SO2F电化氟化制备CF3SO2F过程为研究系统，研究了电化氟化过程操作电压和反应时间的关系、操作条件对氟化产物组成的影响规律以及Ni电极在电化氟化过程的变化情况. 实验结果表明，Simons电化学氟化过程主要由三个步骤组成：F-在阳极发生电化学氧化反应生成F，该步骤是Simons电化学氟化过程的控制步骤；在Ni电极上生成的F与Ni或NiF2反应生成高价NiFn (n≥3)，NiFn为Simons电化学氟化过程的氟化剂；NiFn可以在电极/电解液界面与有机物发生氟化反应生成氟化产物，也可以发生分解反应生成游离F2，NiFn与有机物发生氟化反应的机理与用CoF3等为氟化剂氟化有机物的机理相同. 但NiFn的反应活性比CoF3高，且在实验条件下极不稳定.
关键词： Simons电化学氟化; CH3SO2F; 氟化过程机理
许文林 , 李宝同 , 王大为 , 王雅琼 . 甲基磺酰氟Simons电化学氟化过程特性和机理研究[J]. 电化学, 2017 , 23(3) : 316 -321 . DOI: 10.13208/j.electrochem.161043
The characteristics and mechanism for the Simons electrochemical fluorination processes were investigated during the electrochemical fluorination of CH3SO2F to CF3SO2F. The results showed that the reaction mechanism for the electrochemical fluorination of organic compounds to organic fluorides was the same as that of chemical fluorination processes using fluorinating agents such as CoF3. The electrochemical fluorination in anhydrous HF was a heterogeneous process, and nickel fluorides on the surface of the nickel anode played the role of a mediator in the Simons process to transfer oxidation potential from the anode to the substrate and fluorine from HF to the organic substance. Nickel fluorides were formed electrochemically on the surface of the nickel anode by oxidation of Ni in anhydrous HF to a high valence (with the oxidation stage more than +2) nickel fluorides. The fluorinating agents in electrochemical fluorination processes were NiFn（n≥3）, high valences of nickel produced at the anode, which is much more reactivie than CoF3 and instable under the experimental conditions. The decomposion of NiFn to F2 would take place, and NiFn could also react with organic fluoride. Because F2 is a strong fluorinating agent, NiFn could be decomposed into low molecular weight organic compounds fluorinated products, leading to low current efficiency in process yield and by-products. Therefore, an effective method to improve the process is by increasing the molar ration of organic matter to NiFn on the anode/electrolyte interface.
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