## 3 Results and Discussion
### Analysis of the Family Composition of GC/MS Results of Coal Extracts  
As shown in Figure 4, the family composition analysis was performed on the GC/MS results of 14 groups of coal extracts to obtain information on aliphatic hydrocarbons, aromatic hydrocarbons, oxygenated compounds (alcohols, aldehydes, esters, phenols, ketones, carboxylic acids, ethers, furans, and pyrans), nitrogenous compounds (amides and carbazoles), sulfur-containing compounds (thiophenes), and other compounds.  
Figure 4 shows that both Shenfu coal and Huolinequole coal had no aliphatic hydrocarbons in the THF and THF/methanol extracts. Furthermore, Huolinequole coal also had no aliphatic hydrocarbons in acetone. The content of olefins, chain alkanes, and cycloalkanes in the CS\({}_{2}\) extracts of both was relatively high, and the content of aliphatic hydrocarbons in the other solvent extracts was small in comparison, which proved that a large number of aliphatic hydrocarbons were extracted in the first stage of extraction. The aromatic compounds of Shenfu coal were higher in the CS\({}_{2}\) and acetone extracts, while in the extracts of Huolinequole coal, they were only present in the CS\({}_{2}\) and benzene extracts, and the content of the CS\({}_{2}\) extracts was extremely high. The aromatic compounds in the solvent extracts were dominated by dicyclic aromatic hydrocarbons and tricyclic aromatic hydrocarbons, except for the CS\({}_{2}\) extracts, which contained more polycyclic aromatic hydrocarbons. Shenfu coal oxygenated compounds were present in each type of solvent extracts, but were relatively low in the n-hexane, THF, and THF/methanol extracts. Among them, the phenols were relatively high in the CS\({}_{2}\) extracts, which was due to the strong nucleophilicity of  
\begin{table}
\begin{tabular}{c c c c c c c} \hline \hline
**Extractant** & **8/(cal-cm\({}^{-3}\))1/2** & **Polarity** & **Extraction** & **Aliphatic** & **Aromatic** & **Hetacyclic** \\  & **Parameters** & **Rate/\%** & **Hydrocarbon** & **Content/10\({}^{-4}\) g** & **Content/10\({}^{-4}\) g** \\ \hline CS\({}_{2}\) & 10 & 0.15 & 1.0988 & 23.78 & 53.889 & 13.63 \\ \hline Petroleum ether & 16.1 & 0.01 & 0.0253 & 0.0466 & 0 & 0.014 \\ \hline Benzene & 9.2 & 3 & 0.0440 & 0.016 & 0.101 & 1.187 \\ \hline Methanol & 14.5 & 6.6 & 2.1682 & 0.126 & 0 & 1.348 \\ \hline Acetone & 9.9 & 5.4 & 0.5201 & 0 & 0 & 144.952 \\ \hline THF & 9.5 & 4.2 & 0.9214 & 0 & 0 & 32.571 \\ \hline THF and methanol & 12 & 5.4 & 1.6829 & 0 & 0 & 6.5115 \\ \hline \hline \end{tabular}
\end{table}
Table 2: Extraction rates and composition of extractables in graded extraction of Huolinequole coal.  
Figure 3: Variation of extraction rates with extractant solubility parameters for Huolinequole coal.  
CS\({}_{2}\) and the easy solubilization of the phenols. In contrast, Huolinguole coal had less oxygenated compounds in the petroleum ether, benzene, and methanol extracts. Since diacetone alcohol is like acetone in nature and has better solubility, the acetone extracts contained more than 99% of the two alcohols diacetone alcohol, which could extract the alcohols better. The content of nitrogen- and sulfur-containing compounds in Shenfu and Huolinguole coals was low, and the structure of the elemental analysis was approximately the same as in the previous paper.