Interactions between Coal and Solvent during the Solvent Extraction of Coal in View of Free Radicals
Wenjing He, Shuyue Xu, Muxin Liu, Yibo Zhao, Lanjun Zhang, Tingting Huang, Ziheng Liu
Abstract
, and extraction yield are positively correlated. The charge-transfer capability of the solvent, and in particular its electron-donating capability, plays an essential role in influencing the interaction between the coal and solvent. The increase in the free radical concentration during solvent extraction can be attributed to (1) the formation or decomposition of charge-transfer complexes, (2) dissociation of charge-transfer complexes into radical ions, and (3) breakage of weak covalent bonds. DTG results show the occurrence of weak covalent bonds breakage at temperatures of 133.9-320.1 °C during solvent extraction due to the reduction of the bond energy caused by the formation of radical ions.