Solvolytic liquefaction of coal in the presence of poly (vinylcyclohexane)

Coal liquefaction in the presence of poly(vinylcyclohexane) (PVCH) was studied at 400 °C under an atmosphere of nitrogen. PVCH promoted coal conversion better than tetralin (27.8% for tetralin, 47.2% for preheated PVCH). The effects of the initial molecular weight of PVCH, of free radicals formed during a decrease within molecular weight, and of changes in molecular structure with decomposition were examined. Conversion increased with increased initial molecular weight between 112 amu (ethylcyclohexane) and 700 amu (low molecular weight PVCH); no effect was found for molecular weights greater than 700. The best conversion was obtained when preheated PVCH was used, resulting from formation of allylic hydrogens. Aromatic structures were not found in the preheated PVCH. It is concluded that PVCH with molecular weights of ≈ 700 amu with allylic hydrogens present promoted the liquefaction of coal better than tetralin.