化工学报2017，Vol.68Issue(5)：1882-1891,10.DOI:10.11949/j.issn.0438-1157.20161591
2-氯-5-三氯甲基吡啶电化学氢化脱氯合成2-氯-5-甲基吡啶
Electrochemical hydrodechlorination of 2-chloro-5-trichloromethylpyridine to 2-chloro-5-methylpyridine
摘要
Abstract
Electrochemical hydrodechlorination of 2-chloro-5-trichloromethylpyridine (TCMP) for the synthesis of 2-chloro-5-chloromethylpyridine (CCMP) or 2-chloro-5-methylpyridine (CMP) has important application in preparation of imidacloprid. Feasibility of electrochemical hydrodechlorination of TCMP to CCMP or CMP was first investigated in a weak acidic solvent mixture of methanol, acetic acid and water. Then, influence of cathode material and catholyte composition on electrochemical hydrodechlorination was studied. Finally, influence of supporting catholyte and anolyte on cell voltage and influence of current density and TCMP concentration on efficiency of electrochemical hydrodechlorination were investigated in a plate and frame cell. The experimental results show that: TCMP can be selectively hydrodechlorinated to CMP on a silver mesh cathode in the weak acidic solvent mixture, which cathode material with CMP production rate from high to low is silver, copper, zinc, lead, titanium, graphite, and nickel. Cell voltage is decreased substantially when lithium acetate (CH3COOLi) and sulfuric acid are used to replace tetrabutylammonium perchlorate (TBAP) as supporting cantholyte and anolyte. Efficiency of electrochemical hydrodechlorination is increased by reducing current density and raising initial concentration of TCMP. Under optimized condition (catholyte: 0.2 mol·L?1 CH3COOLi in 10%(vol) CH3COOH and 5%(vol) methanol aqueous solution. Cathode silver mesh, current density 333 A·m?2, temperature 30℃). 0.2 mol·L?1 TCMP is hydrodechlorinated to CMP with yield of 91% at current efficiency of 54% and cell voltage of 3.0 V.关键词
2-氯-5-甲基吡啶/2-氯-5-氯甲基吡啶/银电极/电化学脱氯/板框式电解槽/优化Key words
2-chloro-5-methylpyridine/2-chloro-5-chloromethylpyridine/silver electrode/electrochemical dechlorination/plate and frame cell/optimization分类
化学化工引用本文复制引用
王一想,陈泽伟,张雯,徐颖华,马淳安..2-氯-5-三氯甲基吡啶电化学氢化脱氯合成2-氯-5-甲基吡啶[J].化工学报,2017,68(5):1882-1891,10.基金项目
国家自然科学基金项目(21106133,21576238) （21106133,21576238）
浙江省自然科学基金项目(LY16B060012) （LY16B060012）
国家重点基础研究发展计划项目(2012CB722604).supported by the National Natural Science Foundation of China (21106133, 21576238), the Natural Science Foundation of Zhejiang Province (LY16B060012) and the National Basic Research Program of China (2012CB722604). （2012CB722604）
