Figure 9. Observed vs. calculated values (a) and distribution of the residual (b) of viscosity
It can be seen that most of points are distributed near the diagonal, which means that the calculated value is close to the experimental value. The good prediction results are also denoted withR2 of 0.9676 and the AARD of 3.91 %. Figure 9 (b) showed that the residual distribution of most ILs (about 80 %) log η data in the model are between -0.5~0.5, which further proves the reliability and stability of the model.
351 ionic liquids were divided into 11 categories of cations and 27 kinds of anions. A summary of η estimation of ILs using QSPR method is given in Figure 10, in which the number of fitted data points and the AARD % of each type based ILs are provided.