Sulfide catalysts for hydropurification of oil fractions

Analysis of the literature on catalysis by transition metal sulfides is carried out. Problems which now can be considered solved, and unsolved problems are marked. Catalysts such as Co(Ni)Mo(W) on thermostable oxides are considered. Arguments in support of the hypothesis about formation in the oxide precursors of all this type catalysts of heteropoly compounds (HPC) of Mo(W) are considered. The formation of HPC occurs at the hydrothermal stage of the synthesis of the catalysts under contact of Mo(W) atoms and complexing agents in an acid medium. The role of the complexing agent can be played by atoms of the support (Si, Al, Ti, etc.) or atoms of the modifying additive.