Viscosities and densities of phosphonium-based ionic liquids mixed with dodecane

While phosphonium-based ionic liquids are good solvents for gases, they have high viscosities. Addition of a diluent like dodecane significantly lowers the viscosities of the ionic liquids. In the range 20-90 °C, viscosities and densities were measured for binary mixtures of dodecane with one of five phosphonium-based ionic liquids: Tributylmethylphosphonium bis(2,4,4-trimethylpentyl)phosphinate [TMPP-PA], Tributyltetradecylphosphoniumdodecylbenyzenesulfonate [TTDP-DB], Trimethyloctylphosphoniumbis(2,4,4- trimethylpentyl)phosphinate [TMPP-TP], Trihexyltetradecylphosphonium dicyanamide [TTDP-DC], and Trihexyltetradecylphophonium bis(2,4,4-trimethylpentyl) phosphoniate [TTDP-PA]. For every one of these ionic liquids, addition of 10 wt.% dodecane very much reduces the viscosity but slightly reduces the density.