化工学报 ›› 2016, Vol. 67 ›› Issue (6): 2332-2339.DOI: 10.11949/j.issn.0438-1157.20151444

• 催化、动力学与反应器 • 上一篇    下一篇

锌催化电还原脱氯合成2,3,5,6-四氯吡啶:反应机理和工艺优化

陈泽伟, 王一想, 丁旭芬, 徐颖华, 马淳安   

  1. 浙江工业大学化学工程学院, 绿色化学合成技术国家重点实验室培育基地, 浙江 杭州 310032
  • 收稿日期:2015-09-14 修回日期:2016-02-24 出版日期:2016-06-05 发布日期:2016-06-05
  • 通讯作者: 马淳安
  • 基金资助:

    国家重点基础研究发展计划项目(2012CB722604);国家自然科学基金项目(21106133,21576238)。

Electrochemical reduction of dechlorination of pentachloropyridine to 2,3,5,6-tetrachloropyridine over zinc-based catalyst: reaction mechanism and process optimization

CHEN Zewei, WANG Yixiang, DING Xufen, XU Yinghua, MA Chun'an   

  1. State Key Laboratory Breeding Base of Green Chemistry-Synthesis Technology, College of Chemical Engineering, Zhejiang University of Technology, Hangzhou 310032, Zhejiang, China
  • Received:2015-09-14 Revised:2016-02-24 Online:2016-06-05 Published:2016-06-05
  • Supported by:

    supported by the National Basic Research Program of China ( 2012CB722604 ) and the National Natural Science Foundation of China ( 21106133, 21576238 ).

摘要:

采用循环伏安法和恒电位电解法,探讨了含有ZnCl2的乙睛水混合溶液中五氯吡啶(PCP)在不锈钢阴极表面电还原脱氯生成2,3,5,6-四氯吡啶(2,3,5,6-TCP)的反应机理;采用恒电流电解法对该电还原脱氯过程的各种工艺条件进行了优化。结果表明:该体系中PCP电还原脱氯生成2,3,5,6-TCP主要遵循以Zn/Zn2+为氧化还原媒介的间接电还原机理;优化工艺条件下(阴极液含0.025mol·L-1HCl+15%(体积分数)水+0.2mol·L-1苯磺酸钠+0.16mol·L-1ZnCl2的乙腈溶液;电流密度为1.25A·dm-2),0.08mol·L-1PCP能高选择性地脱氯生成2,3,5,6-TCP,2,3,5,6-TCP的收率和电解电流效率分别可达88.7%和59.1%。

关键词: 五氯吡啶, 2,3,5,6-四氯吡啶, 锌催化机理, 电还原脱氯, 工艺优化

Abstract:

The electrochemical dechlorination mechanism of pentachloropyridine (PCP) to 2,3,5,6-tetrachloropyridine (2,3,5,6-TCP) on stainless steel cathodes in an acetonitrile/water mixed solution containing ZnCl2 was investigated by cyclic voltammetry and constant potential electrolysis methods. Moreover, an optimization of various operating conditions under constant potential electrolysis for the dechlorination process was performed in an H-cell. It showed that indirect electrochemical dechlorination using Zn/Zn2+ as the redox mediator is the main pathway of PCP to 2,3,5,6-TCP. The 0.08 mol·L-1 PCP could be selectively dechlorinated to 2,3,5,6-TCP with 88.7% yield and 59.1% of current efficiency under optimum conditions (catholyte: an acetonitrile solution containing 0.025 mol·L-1 HCl, 15%(vol) water, 0.2 mol·L-1 sodium benzenesulfonate and 0.16 mol·L-1 ZnCl2, and 1.25 A·dm-1 of current density).

Key words: pentachloropyridine, 2,3,5,6-tetrachloropyridine, zinc-catalyzed mechanism, electrochemical reductive dechlorination, process optimization

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