3.1.1 QSPR model proposed for ρ (T, P)
A new ρ (T, P ) model is established to estimate the
temperature and pressure dependent ρ of ILs, as shown in Eq.
(20), and its parameter values are shown in Supporting Information Table
C1.
n =9020, R 2=0.9966, F =44685,Q 2=0.9965, AARD =0.48%,RMSE =0.0097
Where, I ILs, I Ca andI An represent the norm descriptors of ILs, cation
and anion, respectively.
The experimental and calculatedρ values by the model (Eq. (20)) were shown in Supporting
Information Table S1. The comparison between the observed value and the
calculated value, as well as the residual distribution of the model and
Leave-one-out cross-validation (LOO-CV) are shown in Figure 4. Figure 4
(a) indicated that that the model is accurate for most points
distributed nearby, with R 2 of 0.9966,AARD of 0.48 % and RMSE of 0.0097. Figure 4 (b) suggested
that about 96 % ρ data points residuals range from -0.005 to
0.005. Thus, it suggests that the model based on the norm index to
calculate the density is stable and reliable.