Short-Time Reaction Products of Coal Liquefaction and Their Relevance to the Structure of Coal

The structure of chemical classes of soluble coal products produced at short contact times (1—5 min), at temperatures of 400°—425°C, and in the presence of an H-donor solvent relates to the elements of structure in the initial coal. Under these conditions only a few of the chemical bonds present in the coal molecule are actually broken. The fragments (elements of structure) that, linked by weaker bonds, constitute the larger coal molecule differ in molecular weight, functionality, and relative abundance, but the structures of their carbon skeletons are similar for a given coal. The carbon skeleton of a coal, and especially the aliphatic part, is used to distinguish among coals, even those of the same rank. The methodology employed in this work could be used for any coal.