Investigation of free radicals produced during coal liquefaction using ESR

Coal liquefaction experiments are described which were carried out to dissolve a subbituminous coal in low and high hydrogen content solvents, in which liquid samples were periodically withdrawn and examined by electron spin resonance spectroscopy. The objectives of this study were to gain information on the free radical processes involved in coal liquefaction, to determine the relative effectiveness of two solvents (H-donor and non-donor) in influencing the radical processes involved in coal liquefaction and to investigate changes in radical concentration on storage.