Saturate fractions (Sa) were fractionated from the hexane soluble products by the repetitive butylation of Yubari and Taiheiyo coals using zinc and butyl iodide under mild conditions (130°C, under atmospheric pressure), and then fractionated further by gel permeation chromatography (GPC) to investigate the structural features and biological markers.
Yields of Sa for Yubari and Taiheiyo coals were 3 .1 and 5.2 wt% (based on original coals), respectively. Five groups of peaks were present in gas chromatograms of GPC fractions of both Sa, and were consisted of the components as follows: first [Kovats index (KI), 1400-1600], cyclohexane derivatives; second (KI, 1600-1800), cyclohexane and dicyclic ones; third (KI, 1880-2120), di- and tricyclic ones; fourth (KI, 2121-2350), triand tetracyclic ones; fifth (KI, 2350-3620), tetra-and pentacyclic ones . Fifteen biological markers were identified in Yubari Sa, and among them eleven were new components identified in Yubari coal. Because of high yields of solvent soluble products and the mild reaction conditions, many biological markers trapped into coal matrix came to solubilize into Sa.
Some components in Sa seemed to be also butylated, since there were some compounds with the MS fragment of m/e57 and their molecular weight were increased with 56n (n=1, 2).