## 2 Materials and Methods
### Vaporization Thermodynamics of Alkyl-Quinolines and Alkyl-Pyridines
#### 3.3.1 Validation Using Retention Indices \(J_{x}\)
\begin{table}
\begin{tabular}{c c c c c} \hline  & \(J_{x}\) & \(\Delta_{1}^{\mathrm{g}}H_{\mathrm{m}}^{\mathrm{o}}\) (298.15 K) of substituted pyridines and quinolines with their Kovats’s \\ \hline
**Compound** & & **kj\(\cdot\)mol\({}^{-1}\)** & **kj\(\cdot\)mol\({}^{-1}\)** & **kj\(\cdot\)mol\({}^{-1}\)** \\ \hline pyridine & 695 [28] & \(40.2\pm 0.2\) & 40.1 & 0.1 \\  
\hline \end{tabular}  
* Uncertainties are expressed as the twice standard deviation. b Calculated using Equation (4). c Difference between column 3 and 4 in this table.  
\end{table} 
Table 5: Correlation of vaporization enthalpies \(\Delta_{1}^{\mathrm{g}}H_{\mathrm{m}}^{\mathrm{o}}\) (298.15 K) of substituted pyridines and quinolines with their Kovats’s there is no copyright issue indices on non-polar columns. able [20] (see Table 2), but the enthalpy of vaporization is lacking in the literature. The required vaporization enthalpy of \(\Delta_{\rm I}^{\rm S}H_{\rm m}^{\rm o}\)(298.15 K) = 90.3 \(\pm\) 2.7 kJ-mol\({}^{-1}\), was derived from the sublimation and fusion enthalpy as it shown in Table S5. This single value must also be further validated. The few boiling points at the reduced pressures were found for 2-phenyl-quinoline in the SciFinder [11] (see Table S4). The level of the value \(\Delta_{\rm I}^{\rm S}H_{\rm m}^{\rm o}\) (298.15 K) = 95.0 \(\pm\) 4.5 kJ-mol\({}^{-1}\) derived from this data is generally the same as the previous one, even if it is not exact. To ascertain the \(\Delta_{\rm I}^{\rm S}H_{\rm m}^{\rm o}\)(298.15 K) estimate, we searched for the [PERSON]'s index for 2-phenyl-quinoline, but none were found. Instead, we found the chromatographic Lee retention indices, \(J_{Lee}\), for 2-phenylquinoline and its parent compounds. Two independent data sets of Lee indices on the SE-52 column [35] (Table 6) and on the HP-5 column [36] (Table 7) were collected for correlation with vaporization enthalpies. We derived high-quality linear correlations between vaporization enthalpies \(\Delta_{\rm I}^{\rm S}H_{\rm m}^{\rm o}\) (298.15 K) and the sets of Lee indices, \(J_{Lee}\), for both types of chromatographic columns. These correlations are given in the footnotes for Tables 6 and 7 and were used to estimate the enthalpy of vaporization of 2-phenylquinoline independently for each column (see Table 2, column 5). All four \(\Delta_{\rm I}^{\rm S}H_{\rm m}^{\rm o}\)(298.15 K)-entries derived for 2-phenyl-quinoline from phase transition (\(T_{fils}\)), SciFinder (SF), and retention indices (\(J_{x}\)) are in fair agreement, taking into account the assigned experimental uncertainties. The weighted average, \(\Delta_{\rm I}^{\rm S}H_{\rm m}^{\rm o}\) (298.15 K) = 92.7 \(\pm\) 1.2 kJ-mol\({}^{-1}\), was recommended for further thermochemical calculations. \begin{table}
\begin{tabular}{c c c c} \hline \hline  & \(J_{Lee}\)b  & \(\Delta_{\rm I}^{\rm S}H_{\rm m}^{\rm o}\)(298 K)\({}_{\rm exp}\) & \(\Delta_{\rm I}^{\rm S}H_{\rm m}^{\rm o}\)(298 K)\({}_{\rm calc}\)c  \\ \hline
**Compound** & **kJ**\(\cdot\cdot\cdot\)**mol\({}^{-1}\) & **kJ**\(\cdot\cdot\)**mol\({}^{-1}\) & **kJ**\(\cdot\cdot\)**mol\({}^{-1}\) \\ \hline quinoline & 210.2 & 59.3 \(\pm\) 0.2 [14] & 59.1 & 0.2 \\ diphenylamine & 279.3 & 79.5 \(\pm\) 0.4 [37] & 79.4 & 0.1 \\
1-amino-naphthalene & 261.6 & 73.3 \(\pm\) 0.4 [38] & 74.2 & \(-\)0.9 \\
2-amino-naphthalene & 264.3 & 74.6 \(\pm\) 1.0 [38] & 75.0 & \(-\)0.4 \\
2-phenyl-aniline & 273.1 & 78.4 \(\pm\) 0.1 [39] & 77.6 & 0.8 \\
2-phenyl-quinoline & 335.1 & 95.8 \(\pm\) 2.0 & \\ \hline \hline \end{tabular}
\end{table} 
Table 6: Correlation of vaporization enthalpies, \(\Delta_{I}^{\rm S}H_{\rm m}^{\rm o}\) (298.15 K), of amino-aromatics with their Lee indices (\(J_{Lee}\)) on SE-52 column \({}^{\rm a}\).