Reduction of coal in hexamethylphosphoramide-Na-t-BuOH and the molecular weight distribution of pyridine-soluble material

• Published in: Fuel (Guildford) Vol. 59; no. 11; pp. 751 - 756
• Main Authors: Ouchi, Koji, Hirano, Yasuo, Makabe, Masataka, Itoh, Hironori
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 01.01.1980
• ISSN: 0016-2361; 1873-7153
• DOI: 10.1016/0016-2361(80)90249-5

Eight coals were reduced by hexamethylphosphoramide (HMPA)-Na-t-BuOH at room temperature and atmospheric pressure. More than 70 wt % of the coal is soluble in pyridine after this reduction. Coals having ≈88 wt% of carbon content show a maximum solubility in pyridine after reduction. The pyridine-soluble material has a higher H C ratio after reduction. l.r. and n.m.r. spectra show that the reaction product is richer in aliphatic and olefinic structures and that the aromatic ring systems are extensively saturated. From g.p.c. separations and molecular weight measurements, it is found that the molecular weight distribution has a maximum at lower and higher molecular weight values. The average molecular weight of the reduced pyridine-soluble material decreases with increase in rank of the coal. Coking properties of these coals can be related to proportions of material in the two modes of distribution of molecular weight.