Insight into the Compositional Features of Organic Matter in Xilinguole Lignite through Two Mass Spectrometers

Ethanolysis of lignite is an effective approach for converting organic matter of lignite to liquid coal derivatives. Xilinguole lignite (XL) was reacted with ethanol at 320 °C. Then ethanol and isometric carbon disulfide/acetone mixture were used to extract the reaction mixture in a modified Soxhlet extractor to afford extractable portion 1 (EP₁) and extractable portion 2 (EP₂), respectively. According to analysis of EP₁ with a gas chromatography/mass spectrometer, phenolic compounds made up more than 33% of the compounds detected. This could be ascribed to the ethanolysis of XL; that is, ethanol could selectively break the C_alkyl-O bonds in lignite, producing more phenolic compounds. Furthermore, a quadrupole Orbitrap mass spectrometer equipped with an atmospheric pressure chemical ionization source was used for comprehensive analysis of the compositional features of EP₁. The analysis indicated that O_1-3, N₁O_0-2, and N₂S₁O_3-6 were predominant class species in EP₁. Nitrogen atoms in NO-containing organic compounds may exist in the form of pyridine or amidogen, while oxygen atoms primarily exist in furan, alkoxy, carbonyl, and ester groups. In addition, possible chemical structures of NO-containing organic compounds were speculated.