Thermophysical properties of 1-hexyl-3-methylimidazolium tetrafluoroborate [hmim][BF4]Â +Â N-methyldiethanolamine (MDEA) at temperatures (303.15 to 323.15) K

► Densities, viscosities and refractive indices for [hmim][BF4] (1) + MDEA (2)are measured. ► Excess volumes are deduced from the experimental data. ► Densities, refractive indices and the excess volumes were correlated as a function of concentration and temperature. ► Kendall-Monroe model was used to correlate the viscosity data.