Effective catalytic hydroconversion of benzyloxybenzene and oxydibenzene to cyclanes over nickel-supported Y-type zeolite catalyst: Lignite-related model compounds to high-density fuels

Abstract

The catalytic hydroconversion (CHC) of benzyloxybenzene (BOB) and oxydibenzene (ODB), two typical lignite-related model compounds (LRMCs) representing α-Ο-4 and 4-O-5 model linkages, have been investigated using uniformly dispersed Ni15/HY prepared by a three-step method. The cleavage of >CH-O- bridged bonds in BOB and partial hydrogenation of ODB are considered as a crucial first step, and the target reactions in this work are to produce complete hydrodeoxidized ring saturation products. Through the exploration of reaction mechanism, H+/H- and biatomic active hydrogen, as the main hydrogen species involved in the reaction, play an important role in the CHC of BOB and ODB. Herein, the synergic effect between the hydrogenation of nickel nanoparticles and the acidic function of Y-type zeolite improves the CHC performance, resulting in Ni15/HY displaying proficient catalytic activity and selectivity for the CHC of BOB and ODB. Under the optimal reaction conditions, BOB and ODB can be completely converted to cyclanes over Ni15/HY, and the main products are dicyclohexylmethane (57.6 %) and cyclohexane (92.4 %), respectively. The developed Ni15/HY can not only promote the hydroconversion of BOB and ODB to produce ring-saturated products, but also undergo the rearrangement reaction to produce two- or three-ring cyclanes, which is desirable to upgrade LRMCs to high-density hydrocarbon fuels.