Structural Analysis of the Methylated Product of Coal(I)

Solvent Fractionation of Reductive Methylation Product

Abstract

The present report deals with reductive alkylation of coals in order to obtain additional information regarding molecular structure and composition of coal.Yubari (85.6%C) and Taiheiyo (76.9%C) coals which contained six and four methyl groups per 100 original carbon atoms, respectively by reductive methylation followed by extraction with benzene.Subsequently benzene soluble portions were successively extracted with six solvents such as n-hexane, cyclohexane, ethanol, acetone, ethyl acetate, and dioxane.Furthermore benzene insoluble portions were also reductively methylated and extracted with benzene and n-hexane.
Benzene soluble portions from Yubari and Taiheiyo coals constitute 80 and 70 percent of each methylation product, respectively through the twice methylation, and that major portion in them was of n-hexane extract.In addition, each fraction yield with n-hexane, ethanol, and acetone in benzene soluble portion of Taiheiyo coal was greater than that of Yubari coal.From the results of structural analyses of solvent fractionation products by NMR methods, it was found that n-hexane extracts obtained from both coals have the same structural parameters, however unit structures of them were smaller than those of mild hydrogenolyses products.Dioxane extract obtained from Taiheiyo coal has considerably higher average molecular weight than that from Yubari coal;48000 for Taiheiyo, 6000 for Yubari.Moreover unit structures of solvent soluble portions were discussed.