An Insight into a Fascinating DMF-Water Mixed Solvent System: Physicochemical and Electrochemical Studies

Abstract

A systematic study of electrical conductivity, density and viscosity over solutions of tetraethylammonium bromide(TEAB) and 1-butyl-3-methylimidazolium methylsulfate ([BMIM][MeSO4]) in variedly composed dimethyl formamide (DMF) plus water mixtures was carried to explore the potential advantages of such mixed solvent systems for electrochemical investigations. The estimated transport and bulk characteristics of TEAB and [BMIM][MeSO4] in the mixed solvent revealed strong composition dependent interactions are present in the DMF-Water mixed solvent systems. Such results intrigued us to study the impact of solution properties of DMF-water systems on electrochemical behavior of redox probe para-nitrotoluene (PNT).The estimated transport, kinetic and thermodynamic parameters were correlated with the estimated values for viscosity, density and calculated values of dielectric constant for the mixed solvent. The kinetics of PNT was found to be controlled by outer sphere solvent reorganization in DMF-water solvent system for both the supporting electrolytes viz. TEAB and [BMIM][MeSO4], upto composition range of 0.35 mole fraction of DMF in water.