Thermal dissolution (TD) of Shengli lignite was carried out in isometric solvent of methanol and ethyl acetate (EA), methanol, and EA to offer the thermally soluble fractions 1-3 (F 1 -F 3 ), respectively. F 1 -F 3 were analyzed by gas chromatography/mass spectrometry and direct analysis in real-time ionization source/ion trap mass spectrometry (DARTIS/IT-MS). Phenols with 1-4 methyls are the most abundant composition in the extract. The DARTIS/IT-MS analysis shows that the main peaks of the

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... ecular weight distribution of the extract are located at m/z 120-340, and trace signals are still observed at m/z 640. The extract yield of F 1 is higher than those of F 2 and F 3 , even the sum of F 2 and F 3 yields. The roles of EA to lignite TD were investigated by experimental comparison and molecular dynamics simulation. Both the increase in nucleophilicity and the O-H bond extension of methanol due to the formation of intermolecular hydrogen bonds between methanol and EA make the nucleophilic attacking and the scission of O-H bond easier. The transesterification reaction with EA occurs during lignite TD. These results demonstrate that the TD process can be slightly adjusted by altering the microstructure and microenvironment of methanol.