Hydrogenation of phenanthrene in the presence of Ni catalyst. Thermal dehydrogenation of hydrophenanthrenes and role of individual species in hydrogen transfers for coal liquefaction

Mixtures of phenanthrene (P) and hydrophenanthrenes (HPs) of increasing hydrogenation degree (H2P, H4P, H8Ps, H14Ps) were obtained by hydrogenation of P under kinetic control conditions on Ni catalyst at 292 °C and 315 °C under constant hydrogen pressure (7.1–7.8 MPa) for reaction times up to 96 min. Thermal treatments (400 °C, 60 min) of the final mixtures have permitted to define the roles of individual molecular species (in particular H2P and s-H8P) in bimolecular reactions of H-exchange and disproportionation and in unimolecular reactions of isomerization and fragmentation connected to the thermal dehydrogenation. H8Ps, as overhydrogenated donor species, were further examined with regard to the bimolecular reactions at higher temperature (484 °C) and shorter reaction times (10 min) in the presence of P added as coal model.