Coal Dissolution with Alcohol-Tetralin Mixture

Thermal treatments of Taiheiyo and Shin-yubari coals were carried out with various alcohols or alcohol-tetralin mixed solvents (1: 1 by weight) at 350°C and the yields of tetrahydrofuran soluble fraction were determined as a measure of coal dissolution. For Taiheiyo coal the yields for methanol-and ethanoltetralin mixtures were found to be much greater than those for the alcohol or tetralin alone and also greater than those for the mixtures of tetralin with more bulky alcohols such as isopropanol. From these results and the results of the extraction of coals with alcohol-benzene mixture at room temperature, it may not be unreasonable to consider that tetralin in mixture penetrates more extensively into coals than tetralin alone does, by the action of alcohols, probably the swelling of coals. Bulky alcohols may be less permeative. The extent of swelling of coals has been reported to decrease with the decrease of oxygen content of coals and for Shin-yubari coal having low oxygen content there was no substantial difference in the yields among alcohol-and n-hexanetetralin mixtures.