Consistent room temperature electrochemical reduction of gaseous chlorobenzene to value-added intermediates by electroscrubbing

• Published in: Journal of industrial and engineering chemistry (Seoul, Korea) Vol. 89; pp. 334 - 338
• Main Authors: Ramu, A.G., Muthuraman, G., Moon, I.-S.
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 25-09-2020; 한국공업화학회
• Subjects: Electroscrubbing; Gaseous chlorobenzene; Homogeneous electron mediator; MER; 화학공학; Gaseous chlorobenzene; MER; Electroscrubbing; Homogeneous electron mediator
• ISSN: 1226-086X; 1876-794X
• DOI: 10.1016/j.jiec.2020.05.028

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•Room temperature degradation of chlorobenzene by electrogenerated Ni(I) at electroscubbing.•Mediated electrochemical reduction (MER) was confirmed by Ni(I) concentration change.•Gas analyzers confirmed no gaseous intermediates formation.•Solution phase analysis confirm the phenoxide formation from chlorobenzene reduction.
The dehalogenation of gaseous chlorobenzene (CB) to useful intermediates at ambient temperature is desirable. In this study, gaseous CB was dehalogenated to useful intermediates using an electrochemically generated homogeneous low-valent electron mediator in an electroscrubbing column at ambient temperature. A homogenous electron mediator [Ni(I)(CN)4]3− (Ni(I) low-valent) was generated at the cathodic half-cell using a membrane-divided electrolytic cell and quantified by oxidation/reduction potential (ORP) variations with a potentiometric titration. CB removal according to a mediated electrocatalytic reduction (MER) process, was confirmed by the change in electrogenerated Ni(I) from 4.2mM to 2.8mM during the degradation of CB. A Fourier transform infrared gas analyzer and chlorine sensor showed that 100% of 15ppm CB at a 0.2Lmin−1 flow rate had been removed by the MER process with CO2 as the gaseous product. At the same time, the phenoxide anion was found in the resulting solutions, which is a starting material in many pharmaceutical industries. The developed method and possible generation of a homogenous electron mediator on CB dehalogenation to useful intermediates at ambient temperature is a practical technology.