Heteroatom removals from aromatic hydrocarbons over a phosphoric acid-promoted Mn2O3–NiO catalyst Original Research Article

The main objective of this paper is to investigate possible ways to produce high-quality products for transportation fuels from coal-derived oils and heavy distillates including heteroatoms. H3PO4-promoted Mn2O3–NiO catalysts were found to be essentially good for this purpose. The catalysts showed TPR spectra though they are acidic. Through XPS, TPR and NH3-TPD measurements, it was found that the added phosphate played a role in reducing NiO of the catalysts in the presence of hydrogen. This finding was confirmed by the nuclear hydrogenation of naphthalene and anthracene, and heteroatoms removal and ring-opening reaction of carbazole and dibenzothiophene over these catalysts. A Canadian Battle River coal-derived oil sample was used as an empirical sample to estimate the catalyst activity. Among them, the 0.12H3PO4/0.2Mn2O3–0.8NiO catalyst showed the best performance for this purpose; it yielded 30 mol % of HDN products from carbazole, 29 mol % of HDS products from dibenzothiophene, 40 mol % of HDO products and 59 mol % of dearomatization products from the coal-derived oil. Furthermore, it yielded chained and cyclic hydrocarbons by the ring-opening reaction. For comparison, a commercial NiMo/Al2O3 catalyst, HDS-3, was tested; it yielded 6 mol % of HDN products from carbazole, 58 mol % of HDS products from dibenzothiophene and 29 mol % of dearomatization products from the coal-derived oil, but HDO products were insufficient. It was found through comparison that the present catalysts were sufficient for this purpose.