Abstract
Carbon disulfide (CS_2)-N-methyl-2-pyrrolidinone (NMP) mixed solvent (1:1 by volume) give high extraction yields for many bituminous coals at room temperature. Heavy extract fraction, e.g. pyridine insoluble (PI) fraction obtained from the extract of coal was found to become insoluble in the extracting solvent at room temperature. Solubility of PI fraction in the mixed solvent was found to increase greatly by the addition of tetracyanoethylene (TCNE) and 7,7,8,8-tetracyanoquinodimethane (TCNQ). In this study, effects of the addition of various electron acceptors on the extraction yields of coals and solubility of PI fraction are investigated and interactions between coal molecule and electron acceptor are discussed.
