Nickel molybdate-catalysed hydrogenation of brown coal without solvent or added sulfur

Chris K.J. Hulston, Peter J. Redlich, W. Roy Jackson, Frank P. Larkins, Marc Marshall

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19 Citations (Scopus)


Reactions of brown coals, previously impregnated with aqueous solutions of nickel(II) acetate (0.2 wt% Ni, db) and ammonium heptamolybdate (0.6 wt% Mo, db), with hydrogen at 400°C gave very high conversions (up to 92wt% for 60 min reaction time) to products soluble in dichloromethane, water and gas in the absence of reaction solvent or added sulfur. Variation in concentration of the Ni and Mo showed a marked synergistic effect and suggested that the optimum Ni/Mo atomic ratio was ∼0.5, close to that used in many commercial catalysts. High conversions (79wt% dichloromethane-solubles, water and gas) could be obtained from reactions using lower concentrations of catalyst (0.1 wt% Ni + 0.3 wt% Mo), provided that longer reaction times (60 min) were used. Conversions decreased dramatically if the amount of coal in the autoclave increased. Prior treatment of the Victorian coals with alkali solution (NaAlO2 or NaOH) before (but not after) Ni-Mo impregnation led to a significant increase in oil (hexane-soluble) yields when the impregnated coal was dried at 30°C under vacuum. Alkali treatment was found to be beneficial when Ni alone was used, but to have no effect on the conversion of coals with Mo alone.

Original languageEnglish
Pages (from-to)1387-1392
Number of pages6
Issue number12
Publication statusPublished - 1 Jan 1996


  • Alkali treatment
  • Brown coal hydrogenation
  • Nickel-molybdenum catalysts

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