Conductivity and viscosity properties of associated ionic liquids phosphonium orthoborates

摘要

A new group of room temperature molten salts based on asymmetric isobutyl(trihexyl)phosphonium cation with different chelated orthoborate anions are presented in this report. The physicochemical properties of these compounds as glass transition temperature, thermal stability, viscosity and conductivity are determined and discussed on structural basis. The highest room temperature conductivity observed was for the isobutyl(trihexyl)phosphonium bis(malonate)borate. The results indicate that the prepared orthoborates have lower viscosities, better conductivities when compared to their precursor, isobutyl(trihexyl)phosphonium bromide. Our investigation has found that those new compounds have an intermediate-to-fragile behavior. We plotted the conductivity and viscosity data according to Walden's rule and found that they can be classified as an associated ionic liquid (AIL) an intermediate between a true ionic liquid and a molecular species.