The characterization of asphaltenes and preasphaltenes obtained under various coal liquefaction conditions

A CP-MAS 13C NMR study of asphaltenes and preasphaltenes obtained under various coal liquefaction conditions is reported. The carbon aromaticity, fa, of the solid extracts from the reaction products has a close relation with the reaction conditions. By plotting fa against the atomatic HC ratio for these solid products on the characterization chart for model polycyclic aromatic compounds, the molecular structures with relation to the liquefaction pathway from coal to oil can be proposed.