STRONG-INTERACTIONS BETWEEN SELECTED COMPOUNDS AND COAL

Interactions between coal and a coal liquid and also between coal and various standard compounds were investigated. The mixtures were soaked in cyclohexane under nitrogen at 25, 200 and 350-degrees-C for 2 h, and recoveries of the coal liquid and standard compounds were determined by solvent extraction. Nearly 100% of neutral compounds were recovered after the treatment. However, weakly acidic aromatics containing a hydroxyl group and basic aromatics containing nitrogen were seelectively adsorbed on coal even at 25-degrees-C, and complete recovery with tetrahydrofuran and pyridine was difficult. The adsorption of weakly acidic compounds was stronger than that of basic compounds. The adsorption became stronger when the mixtures were soaked at higher temperatures. Similar results were also observed for the coal liquid.