ABSTRACT
The extraction of three coals with mixtures of toluene and pyridine at 350°C were compared. The conversion of both the bituminous and sub-bituminous coals Increased as the amount of pyridine in the mixture Increased up to ca 60% pyridine at a constant gas density of 0.64 g/ml. However, there was no Improvement in conversion for the brown coal when toluene was replaced with pyridine. The difference between pyridine and toluene conversion decreased as the gas density decreased. The high solvent efficiency of pyridine is probably due to the unshared pair of electrons on the nitrogen atom. Addition of other compounds with an unshared pair of electrons on a nitrogen or an oxygen atom also Increased conversion In toluene supercritical gas extraction of a bituminous coal at 350°C and a constant solvent density.