# Densities and Viscosities of Ionic Liquid with Organic Solvents
## 3 Results and Discussion  
### Experimental Density Data  
Table 2 presents the density values of the pure substances together with the literature data to check the experimental apparatus [10; 11; 14; 15; 16; 17; 18]. The standard uncertainty (\(u\)) is \(u(T)\) = 0.01 K. The relative standard uncertainty (\(u_{\rm r}\)) is \(u_{\rm r}(\rho)\) = 0.005. In general, a linear equation or a second-order polynomial function is always used to correlate the density. The function is given as follows:  
\[\rho=a+b\cdot T \tag{1}\]  
where \(\rho\) (g\(\cdot\)cm\({}^{-3}\)) is the experiment density; the parameters of \(a\) (g\(\cdot\)cm\({}^{-3}\)) and \(b\) (g\(\cdot\)cm\({}^{-3}\)\(\cdot\)K\({}^{-1}\)) are correlated using the experimental data; \(T\) is the temperature in Kelvin. \begin{table}
\begin{tabular}{c c c} \hline \hline \multirow{2}{*}{**Compound**} & \multicolumn{2}{c}{**Density/g\(\cdot\)cm\({}^{-3}\)**} \\ \cline{2-3}  & **This Work** & **Literature** \\ \hline
[C\({}_{6}\)mm] [OAc] & 1.01448 & 1.0135 [10], 1.0139 [11] \\ DMA & 0.93202 & 0.93162 [14], 0.93166 [15] \\ DMF & 0.93841 & 0.93900 [14], 0.93793 [16] \\ DMSO & 1.09056 & 1.09041 [17], 1.09073 [18] \\ \hline \hline \end{tabular}
\end{table} 
Table 2: Densities of pure compounds at 303.15 K and atmospheric pressure (0.0967 \(\pm\) 0.002 MPa). To check the experimental values with the literature data, the average absolute relative deviation (AARD) is expressed by:  
\[\text{AARD}(\%)=\frac{100}{n}\sum_{i}^{n}\left|\frac{E_{\text{exp}\,/\text{lit},i }-E_{\text{cal},i}}{E_{\text{exp}\,/\text{lit},i}}\right|, \tag{2}\]  
where \(n\) is the number of data points, \(E_{\text{cal},i}\) and \(E_{\text{exp}/\text{lit},i}\) are the calculated and experiment/literature value of \(i\), respectively. Equation (1) is used to fit the experimental density. Then the calculated value by Equation (1) is compared with the literature data because sometimes the value measured in the experiment is not at the same temperature with that of the literature. Figure 1 shows the relative deviations between the calculated densities of IL using Equation (1) and the literature data. AARD for IL is 0.05% [10], 0.03% [11]. Moreover, in Figures S1-S3 (in the Supplementary Material), the densities of the solvents in this work are compared with the literature data. AARD for DMA is 0.04% [19], 0.08% [20], 0.06% [21], 0.05% [22], 0.88% [23], 0.07% [24], 0.07% [25], 0.06% [26], 0.15% [27], 0.03% [28]. AARD for DMF is 0.02% [29], 0.07% [20], 0.16% [30], 0.10% [19], 0.09% [31], 0.19% [32], 0.18% [33], 0.14% [34], 0.09% [27], 0.09% [35], 0.04% [28], 0.17% [36], 0.07% [37], 0.14% [38], 0.03% [39], 0.13% [40]. AARD for DMSO is 0.14% [41], 0.02% [42], 0.02% [43], 0.01% [44], 0.02% [45], 0.01% [18], 0.03% [33], 0.08% [35], 0.02% [46], 0.05% [47], 0.05% [48], 0.02% [37]. No significant divergence is observed for IL density as well as the organic solvents, indicating that the  
Figures S4-S6 (in the Supplementary Material) depict the densities as a function of the temperature. In the three solvents, DMSO possesses the highest density, while DMA and DMF have similar values. Therefore, the densities of ionic liquid with DMSO possess the highest values compared to those of IL with DMA or DMF.