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This research, aimed to identify a lignin hydrocracking catalyst, was conducted to improve the yields of monophenols and monomers to more than the levels obtained by the Noguchi and HRI (Hydrocarbon Research Inc.) processes. Fifty-five kinds of catalysts {Pd/TiO2, Fe2O3/alumina, NiO-MoO3/alumina, and so forth, metals and metal oxides held by acidic solid carriers (montmorillonite, aluminosilicate, zeolite, Al hydroxide-fillered smectite, TiO2, alumina, and others), acidic composite metal oxides, and others} were tested in the hydrocracking of a kraft lignin (KL) with sulfur in batch stainless-steel autoclaves at 450-515. The Pd/TiO2 had the largest yields of the monophenols of 22 and 30 wt% of KL over the standard yields (17.6 and 25.3 wt%) from the hydrocracking with a Fe2O3/alumina catalyst used in the HRI process at 450 and 490, respectively. The Pd system catalysts as a whole promoted the degradation of KL and produced large yields of monophenols. The Mo system catalysts were suitable to produce liquid fuel and benzenes because both the monomerization and dehydroxylation rates were greater.