Rapid Cleavage of Carbon-Carbon and Carbon-Oxygen Bonds in Coal Structures

摘要

The cited illustrate that: (1) 1,2-Diarylethanes (which are probable sub-units in real coals) have central bonds sufficiently weakened to undergo homolysis at rates consistent with the dissolation of coals at 400 deg C. (2) The presence of phenolic groups on diarylmethanes can make structures containing no weak carbon-carbon or carbon-oxygen bonds moderately reactive by way of a mechanism involving ionic tautomerization to the keto isomer followed by central bond homolysis. (3) The presence of additional hydroxy groups, and/or homogeneous or hetergeneous catalysts can amplify these effects such that strongly bonded diaryl methane structures can have half-lives of several minutes or less at 400 deg C. The resulting rates are well into the region where these structural features could contribute to the rapid dissolution of coals at 400 deg C. Thus, a combination of homogeneous ionic, free radical, and/or heterogeneously catalyzed reactions can account for rapid fragmentation of certain strongly bonded coal structures. It is not neccessary, at least on the basis of rate, to invoke exclusively the break-up of hydrogen-bonded structures or other non-radical depolymerization processes to explain rapid dissolution of coals. 8 refs., 1 fig., 1 tab. tab. (ERA citation 11:015466)