An unprecedented route of •OH radical reactivity evidenced by an electrocatalytical process: Ipso-substitution with perhalogenocarbon compounds

Hydroxyl radical (center dot OH) is ubiquitous in the environment and in metabolism. It is one of the most powerful oxidants and can react instantaneously with surrounding chemicals. Currently, three attack modes of center dot OH have been identified: hydrogen atom abstraction, addition to unsaturated bond and electron transfer. Perhalogenocarbon compounds such as CCl4 are therefore supposed to be recalcitrant to center dot OH as suggested by numerous authors due to the absence of both hydrogen atom(s) and unsaturated bond(s). Here, we report for the first time a fourth attack mode of center dot OH through ipso-substitution of the halogen atom. This breakthrough offers new scientific insight for understanding the mechanisms of center dot OH oxidation in the related research areas of research. It is especially a great progress in organic contaminants removal from water. In this study, CCl4 is successfully degraded and mineralized in aqueous media using a green and efficient electrocatalytical production of homogeneous and heterogeneous center dot OH. Maximum degradation rate of 0.298 min(-1) and mineralization yield of 82% were reached. This opens up new possibilities of emerging water pollutants elimination such as fluorosurfactants.