Peroxide derivatives of molybdenum(VI) in neutral and alkaline media

Influence of the MoO42- Ions on the Bray−Liebhafsky Oscillatory Reaction

“…The MoO 4 2- ions effect upon the BL oscillations described above can be explained from the point of view of the oxidation of iodine by hydrogen peroxide catalyzed by molybdate as described by us, as well as from the point of view of the hydrogen peroxide disproportionation catalyzed by molybdate. − The oxidation of iodine by hydrogen peroxide is one of the main stoichiometric processes of the BL reaction, but in general it proceeds too slowly to correspond to real interactions of the involved species during the BL reaction. Treindl and Noyes 6 proposed the reaction mechanism involving 10 individual steps, the seventh of which is the interaction of I radicals with O 2 produced by the reduction of iodate by hydrogen peroxide According to them, oxygen is not only one of the products of the BL reaction but also an intermediate.…”

Oxidation of thioanisole by peroxomolybdate ions: direct oxygen transfer from tetraperoxomolybdate ion

“…(2)]. 11,12 Initial sul®de oxidation When excess PhSMe is added to the red-brown solution of Na 2 MoO 4 (ca 10 À3 M) 11 The initial decrease and subsequent recovery of absorbance ( Fig. 1) shows that after the initial reaction with PhSMe the concentration of MoO 2 2À 4 does not change for ca 10 min, and within that time it can be regarded as in steady state.…”

“…The tetraperoxomolybdate MoO 2 2À 4 is much more reactive than the triperoxo species MoOO 2 2À 3 , but in dilute H 2 O 2 the latter is the dominant complex, 11,12 4 by PhSMe shows that this reaction is a direct oxygen transfer, as for oxidations by mixed peroxomolybdate complexes in organic solvents that have very low activation energies, 16 as is typical of direct oxygen transfers to sulfides from inorganic oxidants. 20 Oxidation by MoOO 2 2À 3 is also shown as a direct oxygen transfer, but our data do not exclude the possibility of a contribution of reaction involving 1 O 2 .…”

“…Aqueous molybdate ions and H 2 O 2 form a series of peroxomolybdates whose compositions depend on concentrations and pH, 10 but with dilute molybdate ion and mildly alkaline pH mononuclear complexes have been characterized. 11,12 With [H 2 O 2 ] >0.08 M the tri-and tetra-peroxo molybdates coexist 12 and the association equilibrium constant is 1.58 M À1 in water at pH % 9.4. 11 The pK a of H 2 O 2 is ca 11.5, 13 and the high nucleophilicity of HO À 2 should permit its reaction with toxic phosphonyl derivatives in these conditions.…”

Studies on electrochemical dissolution of sintered molybdenum discs as a potential method for targets dissolution in 99mTc production

“…Several possibilities of electrochemical dissolution of molybdenum were reported [44][45][46][47]. However, described techniques are not adapted to our purpose.…”