  Ionic liquids (ILs) are an emerging group of chemical compounds which possess
promising properties such as having negligible vapor pressure. These so called
designer solvents have the potential to replace volatile organic compounds in
industrial applications. A large number of ILs, through the combination of
different cations and anions, can potentially be synthesized. In this context,
it will be useful to intelligently design customized ILs through computer-aided
methods. Practical limitations dictate that any successful attempt to design
new ILs for industrial applications requires the ability to accurately predict
their melting point and viscosity as experimental data will not be available
for designed structures. In this paper, we present two new correlation
equations towards the more precise prediction of melting point and viscosity of
ILs solely based on the inputs from quantum chemistry calculations (no
experimental data or simulation results are needed). To develop these
correlations we utilized data related to size, shape, and electrostatic
properties of cations and anions that constitutes ILs. In this work, new
descriptors such as dielectric energy of cations and anions as well as the
values predicted by an ad-hoc model for the radii of cations and anions
(instead of their van der waals radii) were used. An enormous form of
correlation equations constituent of all different combinations of descriptors
(as the inputs to the model) were tested. The average relative errors were
measured to be 3.16% and 6.45% for the melting point, Tm, and ln(vis),
respectively.
