Correlation and Prediction of the Transport Properties of Ionic Liquids
A modified version of the rough hard sphere (RHS) scheme of Gacino et al. has been used to correlate the viscosity and thermal conductivity of ILs. A total of 661 viscosity data at 0.1 MPa for 48 ILs, and 159 thermal conductivity data at 0.1 MPa for 26 ILs were correlated, with average absolute deviations between calculated and experimental values (AAD) of 1.15 in the case of the viscosity and 2.32 in the case of the thermal conductivity. In addition, a total of 453 viscosity data for 10 ILs and 95 thermal conductivity data for 9 ILs over a pressure range of 0.1 MPa to 35.6 MPa were correlated with AADs of 3.46 in the case of the viscosity and 2.89 in the case of the thermal conductivity. More importantly, the three parameters of the modified RHS scheme were found to exhibit regular trends with the molecular weight of ILs with a common anion. Finally, IL mixture viscosities were predicted within their experimental uncertainties using a simple mixing rule. Mixtures of water and ILs could also be accommodated within the RHS scheme, although errors were higher in this case.