In order to clarify the effect of pretreatment on liquefaction reactivity of coal, transferable hydrogen (TH) of coal cleaned by gravity separation method was assessed using anthracene as hydrogen acceptor. The amount of TH in River King coal decreased with increasing ash content. The amount of TH was not necessarily correlated with H/C atomic ratio. Organic part of IR spectra of coals was hardly changed by gravity separation. It was recognized that the higher the vitrinite content and the lower the inertinite content, the larger is the amount of TH. Correlations between the amount of TH and the liquefaction yields for the cleaned coal were observed. Except for River King coals, no simple correlation exists between the amount of TH and the total conversion in liquefaction of various coals. On the other hand, good correlation was obtained between the amount of TH and (Asphaltene+Oil) yield. TH is a desirable parameter in evaluating the liquefaction reactivity of coal. The amount of hydrogen requisite to depolymerization of coal was examined on the basis of the model assuming that coal is a simple polymer and was compared with the amount of transferable hydrogen.
