ACTIVITY AND SELECTIVITY OF SLURRY-PHASE IRON-BASED CATALYSTS FOR MODEL SYSTEMS

The activity and selectivity of iron-based slurry-phase catalysts were investigated for the hydrogenation of pyrene and the hydrocracking of C-C bonds in several model compounds: 1-methylnaphthalene (1-MN), 2-h exylnaphthalene (2-HN) and 4-(1-naphthylmethyl)bibenzyl (NMBB). Reacti ons were performed under typical coal liquefaction conditions. Higher reaction temperature and the presence of sulfur increased the hydrogen ation of pyrene by the iron catalysts generated in situ. The in situ m ethod of catalyst addition was most effective for pyrene hydrogenation for the. iron catalysts, while molybdenum naphthenate showed increase d activity with two-stage processing. Both Fe and Mo catalysts showed low activity in reactions where the catalyst was generated ex situ. Co mbinations of Fe and Mo catalysts were synergistic for pyrene hydrogen ation, although the amount of increase was dependent upon the particul ar iron precursor used. The Fe and Mo catalysts affected the hydrocrac king of the three model species differently. Molybdenum naphthenate wa s more active for hydrocracking 2-HN and NMBB than any of the Fe catal ysts, but combining FeNaph with MoNaph was detrimental to the hydrocra cking of these compounds. The selectivity of hydrocracking NMBB at spe cific bonding sites was affected by the presence and type of catalyst, presence of sulfur, and reaction time.