Nonradical reactions during coal conversion. A search for synchronous 1,1-hydrogen addition as a precursor to radical reactions

Previous studies on the relative reactivity of H-2 and tetralin have shown greater hydrogen transfer from H-2 to coal than from tetralin to coal at 35 0 degrees C. These results are not consistent with a radical pathway for hy drogen addition and require the existence of a nonradical route. We explore d the possibility that this nonradical route is synchronous 1,4-H-2 additio n, which could occur either with acenes or with dihydroxybenzenes. Reaction s of Illinois No. 6 coal with added phenanthrene, anthracene, or m-dihydrox ybenzene provide no evidence in support of this addition reaction. The 1,4- addition of H-2 to phenols produces carbonyl compounds. Reactions of Wyodak coal, which should have a higher population of phenolic groups than Illino is No. 6, show no evidence for a correlation of CO production with H-2 util ization or for changes in carbonyl group population that would be consisten t with 1,4-addition to phenols. In light of these negative findings, the li kely nonradical pathway would then seem to be catalysis by mineral matter. This possibility was probed by comparing reactions of untreated and deminer alized Wyodak. The untreated coal, in the absence of solvent, gives higher liquid yields and proportionately more oils and asphaltenes at the expense of preasphaltenes than does the demineralized coal. This indicates a role f or the mineral matter in H-2 utilization.