Removing coal radicals by chemical reduction

The radical population of Wyodak coal was decreased by reaction with the re ducing agents SmI2, YbI2, and CrCl2. The latter is the most effective, remo ving 67% of the radicals. It is also the easiest to prepare. The swelling o f Wyodak coal in toluene, THF, and pyridine is independent of the coal's ra dical population demonstrating that radical sites are not responsible for i ntermolecular associative interactions.