Ionic Liquid Induced Enhancement in the Stickiness of Sticky Dissociative Electroreductive C-Cl Bond Cleavage: A Key to Eco-Green Detoxification of Chloroacetonitrile

摘要

Detailed voltammetric investigations that demonstrate the potential of 1-butyl-3-methyl imidazolium tetrafluoroborate ([BMIM][BF4]), a commonly used room-temperature ionic liquid (RTIL), to enhance the stickiness in the sticky dissociative electrodetoxification pathway for chloroacetonitrile are presented. Convolution analysis of the voltammetric data in light of the Marcus-Hush formulation reveals that electroreductive cleavage of the C-Cl bond of chloroacetonitrile (ClCH2CN) in [BMIM][BF4] follows a sticky dissociative pathway like that in conventional organic solvents. Interestingly the interaction energy between Cl- and CNCH2 center dot (radical) in [BMIM][BF4] is observed to be almost ten times higher than that reported for the same species in N,N-dimethylformamide (DMF). This RTIL-induced enhancement in the interaction energy among the electrochemically generated fragments reduces the kinetic barrier and hence the overpotential required for heterogeneous electroreduction of ClCH2CN. The lower overpotential that implies lesser energy consumption for the electroreduction and the green features of [BMIM][BF4] jointly support the use of imidazolium-based RTILs for eco-green electrodetoxification of halohydrocarbons like chloroacetonitrile. (C) 2016 Elsevier Ltd. All rights reserved.