A Group Contribution Method for the Thermal Properties of Ionic Liquids

Missing
substance properties can become a limiting factor in research
and process design. Especially for ionic liquids (ILs), experimental
data are often not available and measurement is expensive and time-consuming.
To cope with this issue, an estimation scheme for the heat capacity
and the thermal conductivity of ILs has been developed. To achieve
a wide range of application, first-order group contributions have
been chosen to describe the molecular structure of the ions. 2419
experimental heat capacity data points for 106 ILs have been used
in two separate subsets for parameter fitting and testing to allow
for a reliable external validation. In the case of thermal conductivity,
372 data points for 39 ILs have been processed analogously. The data
for ILs from the subset not used for the fitting could be reproduced
with a mean absolute error of 5.4% in the case of heat capacity and
of 8.1% in the case of thermal conductivity. Using these estimation
schemes, it is possible to screen a huge number of potential combinations
of cations and anions to find candidates suited best for a specific
task before performing the experimental measurement.