Abstract <p>The composition and structure of the products obtained by thermal solution of Kaa-Khem coal in benzene, in supercritical conditions, are studied by IR spectrometry. Comparison of the IR spectra of the initial coal, the liquid product, and the insoluble solid residue shows that the position of the individual peaks is practically unchanged but the intensity of the absorption bands in all four spectral regions is different. The intensity is higher in the liquid product that in the initial coal but, conversely, is lower in the solid residue.</p>