Complexes forming from ammonium paramolybdate, orthophosphoric acid, cobalt or nickel nitrate, and carbamide in solution and their use in the preparation of diesel fuel hydrodesulfurization catalysts

It is demonstrated by 14 N, 17 O, 31 P, and 95 Mo NMR spectroscopy that the heteropolyanion [P 2 Mo 5 O 23 ] 6− forms in impregnating solutions containing orthophosphoric acid, ammonium paramolybdate, cobalt or nickel nitrate, and carbamide. The anion forms labile complexes with Co 2+ or Ni 2+ cations by coordinating to them through terminal oxygen atoms of the MoO 6 octahedra and outer oxygen atoms of the PO 4 groups. The catalysts prepared by supporting these complexes on Al 2 O 3 are highly active in diesel fuel hydrodesulfurization. They compare well with the best foreign analogues and are superior to most of the Russian commercial hydrodesulfurization catalysts.