Influence of temperature on thermophysical properties of tri(butyl)methylphosphonium methyl sulfate + N-methyl-2-pyrrolidone

In this work, densities (ρ), ultrasonic sound velocities (u) and viscosities (η) for binary mixture of tri(butyl)methylphosphonium methyl sulfate ([P4441][CH3SO4]) with N-methyl-2-pyrrolidone (NMP) were measured over the entire composition range at temperatures ranging from 293.15 to 323.15 K in steps of 5 K under atmospheric pressure. The derived properties such as excess molar volumes (VE), deviation in isentropic compressibilities (Δκs) and deviation in viscosities (Δη) are obtained from ρ, u and η data, respectively. The derived properties were correlated accurately with the Redlich-Kister type equation. The VE, Δκs and Δη values for the aforesaid systems are negative over the entire composition range under the present experimental conditions. The molecular interactions and structural effects were examined on the basis of measured and derived properties. The obtained results are useful for describing the intermolecular interactions, developing structure-property correlation and molecular modeling that exist between [P4441][CH3SO4] with NMP mixture.