Structural characterization of non-reductively ethylated coal by 13C and 1H n.m.r

A major portion of some coals can be solubilized by non-reductive ethylation. A part of the solubilized portion of a bituminous highly caking coal was studied by 1H and 13C nuclear magnetic resonance techniques. It was demonstrated that important structural information can be obtained by this method for the original insoluble material in coal. It was found that, in the investigated coal, about 40% of the aromatic carbon atoms are protonated and that 6–10% of total carbon atoms existed in original coal as active sites that were amenable to ethylation.