STRUCTURAL-ANALYSIS OF LOW-RANK-COAL EXTRACTS AND THEIR RELATION TO PARENT COALS

The chemical structure of low-rank coals was studied. Research was done to find an extraction solvent suitable to obtain a representative fraction of low-rank coals; The structural study was performed with the aid of elemental analysis, FTIR, liquid H-1 NMR, and C-13 CP/MAS NMR spectroscopies and vapor-phase osmometry. It was found that successive extraction of coal with. tetrahydrofuran and chloroform could be a promising extraction paths various structural parameters of the extract fractions obtained were near to those of their parent coals. On the basis of the results obtained, the concept of the monophase rather than the host/guest coal structure model is discussed.