对苯醌电化学捕获CO_(2)机理研究及捕获产物的结构分析

Mechanism of Electrochemical Capture of CO_(2) by p-Benzoquinone and Structure Analysis of the Products

利用循环伏安法(CV)、现场红外光谱法、恒电位电解法开展了BQ在乙腈溶液中的电化学捕获CO_(2)的研究。结果显示,CO_(2)在BQ还原过程中被一价阴离子自由基BQ·-所捕获,表明BQ·-是可以当作亲核试剂来捕获CO_(2)。采用恒电位电解的方法,得到了BQ电化学捕获CO_(2)后的终产物。1H-NMR、IR、13C-NMR以及元素分析的结果表明,捕获CO_(2)后的终产物为BQ与CO_(2)进行化学反应的加合物,其化学计量比为1∶2,且亲核进攻CO_(2)的是BQ羰基上的氧,形成较为稳定的羧酸式结构。产物酸化处理生成对苯酚,进一步证明BQ电化学捕获CO_(2)产物结构。

The electrochemical capture of CO_(2) by BQ in acetonitrile solution was studied by cyclic voltammetry(CV), field infrared spectroscopy and potentiostatic electrolysis. The results showed that CO_(2) is captured by the monovalent anion radical BQ· in the twostep single electron transfer process,which indicates that BQ· can be used as a nucleophile to cap ture CO_(2). Then the precipitation products of CO_(2) captured by BQ electrochemistry were obtained by potentiostatic electroly sis. According to the results of 1HNMR,13CNMR and elemental analysis,it can be deduced that the product is the ad duct of chemical reaction between BQ and CO_(2),the stoichiometric ratio of CO_(2) captured by BQ electrochemical is 1∶2,and the nucleophilic attack on CO_(2) is the oxygen on the carbonyl group of BQ,forming a relatively stable carboxylic acid struc ture. After acidifying the product,the product was transformed into pphenol. This further proves the rationality of the struc ture inference of CO_(2) products captured by BQ electrochemistry.