The self-diffusion coefficient of pure liquids, a fundamental
transport
property, is involved in a wide range of applications. Many methods
have been employed to study the self-diffusion coefficient, with the
most popular being semiempirical models. The quantitative structure–property
relationship (QSPR) has been widely used to predict various physicochemical
properties of substances, but the appropriate molecular descriptors
must be selected first. In this study, the charge density distribution
area of molecules at a specific interval (S
σi
) and cavity volume (V
COSMO) was determined based on the conductor-like screening model for
the segment activity coefficient (COSMO-SAC). Using these molecular
descriptors, a backpropagation artificial neural network (BP-ANN)
method was employed to construct a nonlinear QSPR model that can predict
the self-diffusion coefficients of pure liquids under normal pressure.
The data set used included 2596 data points for 238 compounds, covering
a self-diffusion coefficient range of 8.74 × 10–13 to 8.66 × 10–9 m2·s–1 and a temperature range of 90.5–475.1 K. The coefficients
of determination (R
2) of the BP-ANN model
on the training, validation, and testing sets were all greater than
0.99. For the entire data set, the R
2,
absolute average relative deviation (AARD), and root mean square error
(RMSE) were 0.9940, 7.09%, and 0.1106, respectively. In an application
domain (AD) analysis, 94.67% of the data were within the AD range
of the model. Consequently, the model developed in this study can
satisfactorily predict the self-diffusion coefficients of liquids.