A study has been made of the liquefaction of Itatsk field coal in a hydrogen-donor solvent (Tetralin) with a heating rate of the reaction system of 120 deg/min. H-1 NMR spectroscopy, osmometry and gas chromatography have been used to study the influence of temperature on the chemical composition of heavy liquid products (extracts). On the basis of the results obtained, certain relationships governing the chemical conversions of hydrocarbons of the organic mass of coal during liquefaction have been established.