Electrochemical reduction mechanism of 4-nitrobenzyl bromide in ionogel membranes

Abstract

Ionic liquid-based electrolytes (ILs) have gained tremendous attention as sustainable, green electrolytes for electrochemical processes due to their negligible vapour pressure and high boiling points. A rising trend is to fabricate solid electrolytes based on ionic liquids to address the risk of leakage associated to liquid electrolytes. These solid electrolytes, which are commonly known as ionogel membranes (IGs), contain the intrinsic properties of ILs, while having excellent mechanical strength. These characteristics make them ideal for investigating reaction mechanisms and facilitating electrosynthesis processes. By providing a stable and conductive environment, ionogels enable precise control and monitoring of electrochemical reactions in solid electrolytes, leading to more accurate and reproducible results. Their application not only enhances our understanding of fundamental electrochemical processes but also paves the way for innovative advancements in electrosynthesis, contributing significantly to the development of new materials and technologies. In this body of research, the reduction mechanism of p-nitrobenzyl bromide (p-NBBr) is studied and disclosed in IG membranes for a first time. We successfully performed a controlled potential electrolysis of p-NBBr in IG membranes, as well as studying two different electrochemical setups to obtain the most optimal configuration. We also demonstrate that the addition of electrolyte additives, such as lithium bis(trifluorometahnesulfonyl)imide (Li TFSI), in the IG composition raises the ionic conductivity of the resulting membrane from 0.15 up to 0.2 mS/cm.