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, et al. Electrochemical reduction of dechlorination of pentachloropyridine to 2,3,5,6-tetrachloropyridine over zinc-based catalyst: reaction mechanism and process optimization[J]. CIESC Journal, 2016, (6): 2332-2339.
CHEN Zewei, WANG Yixiang, DING Xufen, et al. Electrochemical reduction of dechlorination of pentachloropyridine to 2,3,5,6-tetrachloropyridine over zinc-based catalyst: reaction mechanism and process optimization[J]. CIESC Journal, 2016, (6): 2332-2339.DOI: 10.11949/j.issn.0438-1157.20151444.
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