IODINE-CATALYZED COAL-LIQUEFACTION

Coals of two different ranks were liquefied in high yields using catalytic quantities of elemental iodine or iodine compounds. Iodine monochloride was found to be especially effective for enhancing both coal conversion and product quality. It appears that enhancement in coal conversion is due to the unique ability of iodine to catalyze radical-induced bond scission and hydrogen addition to the coal macromolecule or coal-derived free radicals. The starting iodine can be fully accounted for in the reaction products as both organic-bound and water-soluble forms. Uncoverted coal and the heavy product fractions contain the majority of the organic-bound iodine. The results of iodine-catalyzed coal reactions emphasize the need for efficient hydrogen atom transfer along with bond scission to achieve high conversion and product quality.