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.