Liquid Properties of Ionic Liquids Based on Phosphonium Cations with (Alkylthio)alkyl Groups

Herein, we report the liquid properties, that is, densities, viscosities, electrical conductivities, surface tensions, melting points, and glass transition temperatures, of 18 novel sulfur-containing phosphonium cation- (triethyl[(methylthio)methyl]phosphonium, triethyl[2-(methylthio)ethyl]phosphonium, triethyl[2-(ethylthio)ethyl]phosphonium, tributyl[(methylthio)methyl]phosphonium, tributyl[2-(methylthio)ethyl]phosphonium, tributyl[2-(ethylthio)ethyl]phosphonium) based ionic liquids with bis(trifluoromethylsulfonyl)amide, bis(fluorosulfonyl)amide, and tetrafluoroborate anions. The effects of the (alkylthio)alkyl groups on the viscosity and surface tension of the ionic liquids are very different from those of common alkyl groups in typical ionic liquids.