Reactions with other transition metals
For the purpose of this paper, other transition metals refer to pure Ni, Mo, Co, W, their composites (i.e. bimetallic or trimetallic systems) or even the supported materials. These materials,especially the sulfide compounds, have been previously tested in the hydrotreatment of petroleum fractions [39–43], and are therefore currently being evaluated as replacement catalysts for the HDO and HDC of vegetable oils.