Solubilization of Coals by Reductive Alkylation

Reductive methylation of Tempoku, Taiheiyo, and Yubari coals and pyridine extract and residue of Yubari coal were carried out. Molecular structure of the reaction products was investigated by IR-spectra, nagative charges added per 100 carbon atoms, benzene solubility, and the contents of oxygen-containing groups before and after treatment with K/THF/Naphthalene/CH3I. Furthermore, as the methylated pyridine extract become more dissolving in banzene than the others (>90%), fractionna-tion was done with n-hexana and acetone, and then the average molecular structure of each fraction was estimated by NMR -spectra.Nagative charges and solubility in benzene of coals treated were increased with increasing the amount of naphthalene and with reaction time. The solubility of methylated coals in benzene was more belileved to be due to the number of CH3 groups introduced and the formation of naphthene rings than to be due to the degradation of aromatic rings. From the estimation of oxygen-containing functional groups, it was found that the more hydroxyl content in coal decreased, the more methoxyl content increased by reductive methylation. Mechanism of methylation and naphthene rings formation of aromatic rings occured during reductive methylation were alsoi nterpreted from the structural prameters of NMR.The structural parameters by Williams method did not partially agree with those obtained by Brown, Lander and Takeya's method e. g. number of aromatic rings and these carbon atoms per molecule.