Catalytic hydroconversion of oxydibenzene and benzyloxybenzene over NiCs/Al2O3

NiCs/Al 2 O 3 with medium-strong alkaline and the contents of Ni and Cs of 26.55 wt% and 0.02 wt%, respectively, was prepared by a three-step method and characterized with multiple tools. Oxydibenzene (ODB) and benzyloxybenzene (BOB) were used as low-rank coal-related model compounds and their catalytic hydroconversion (CHC) were investigated over NiCs/Al 2 O 3. Under mild conditions (MCs), NiCs/Al 2 O 3 can effectively activate H 2 to biatomic active hydrogen (H···H) and part of H···H can be effectively split to relative mobile H - and immobile H + on the NiCs/Al 2 O 3 surface. Both ODB and BOB can be completely converted and full hydrogenation (FH) of the benzene ring (BR) in −O-BR is the first step for the CHC of both ODB and BOB via H···H transfer to the BR under MCs. Subsequently, H - transfer to an ipso -carbon (IC) in the resulting oxydicyclohexane from the FH of ODB cleaves an −O-CH< bond to produce cyclohexane (CH I ) and cyclohexyloxy anion (CHOA), which abstracts H + from H···H to afford cyclohexanol (CH II ) followed by H - transfer to the IC in CH II and subsequent HO – release to yield CH I . As a result, CH I is the only final product from the CHC of ODB. In contrast, H - transfer preferentially proceeds to the carbon atom in the –CH 2 - of the resulting benzyloxycyclohexane from the FH of the BR in −O-BR of BOB to produce toluene and CHOA followed by the FH of toluene to get methylcyclohexane and the H + abstraction by CHOA from H···H to obtain CH II . Moreover, NiCs/Al 2 O 3 shows a distinguished recyclability and repeatability.