The activity of synthetic iron oxyhydroxide catalysts for a brown coal liquefaction was investigated. γ-Iron oxyhydroxide catalysts finely divided in a coal-liquefied solvent gave much higher oil yields compared to other iron-based catalysts. The high activity was considered to be because synthetic γ-iron oxyhydroxides consisted of fine primary particles and because they highly dispersed in a reaction medium that is a coal-liquefied solvent.
