Ionic liquids (ILs) provide a promising solution in many
industrial
applications, such as solvents, absorbents, electrolytes, catalysts,
lubricants, and many others. However, due to the enormous variety
of their structures, uncovering or designing those with optimal attributes
requires expensive and exhaustive simulations and experiments. For
these reasons, searching for an efficient theoretical tool for finding
the relationship between the IL structure and properties has been
the subject of many research studies. Recently, special attention
has been paid to machine learning tools, especially multilayer perceptron
and convolutional neural networks, among many other algorithms in
the field of artificial neural networks. For the latter, graph neural
networks (GNNs) seem to be a powerful cheminformatic tool yet not
well enough studied for dual molecular systems such as ILs. In this
work, the usage of GNNs in structure–property studies is critically
evaluated for predicting the density, viscosity, and surface tension
of ILs. The problem of data availability and integrity is discussed
to show how well GNNs deal with mislabeled chemical data. Providing
more training data is proven to be more important than ensuring that
they are immaculate. Great attention is paid to how GNNs process different
ions to give graph transformations and electrostatic information.
Clues on how GNNs should be applied to predict the properties of ILs
are provided. Differences, especially regarding handling mislabeled
data, favoring the use of GNNs over classical quantitative structure–property
models are discussed.