Nickel ion, as catalyst for decomposition

Nickel catalyst, Raney, in preparation of 2,2 bipvndine, 46, 5 VV7 J, preparation of, 46, 5 Nickel ion, as catalyst for decomposition of diazomum xanthates, 47,... 

It was found that the value of F, is markedly increased by ions which are effective catalysts of oxidation reactions of peroxydisulphate. These are silver(I) copper(n), and iron(III). Cobalt(II) and nickel(II) ions, although they are good catalysts for the decomposition of hydrogen peroxide, exert their effect merely as inert electrolytes in the induced reaction. Therefore it can be concluded that, in this process, activation of the rather less reactive 8203 is more important than that of hydrogen peroxide . ... 

CO2 molecule, or Mg + and CO2 play the role of oxide acceptor to form water, carbonate, and MgC03, respectively [38]. The reactions of the iron carboxylate with these Lewis acids are thought to be fast and not rate determining. For the cobalt and nickel macrocyclic catalysts, CO2 is the ultimate oxide acceptor with formation of bicarbonate salts in addition to CO, but it is not clear what the precise pathway is for decomposition of the carboxylate to CO [33]. The influence of alkali metal ions on CO2 binding for these complexes was discussed earlier [15]. It appears the interactions between bound CO2 and these ions are fast and reversible, and one would presume that reactions between protons and bound CO2 are rapid as well. 

The nickel dithiocarbamates (Vllb) are hydroperoxide decomposers [21]. Unlike the zinc analogues, they are light stable and effective UV screening agents below 340 nm [30]. They react rapidly with hydroperoxides as they are formed in the photo-oxidizing polymer to give sulphur acids which are catalysts for hydroperoxide decomposition [21] and are themselves converted to nickel sulphate (see Scheme 1.5). This chemistry leads to the eventual depletion of the metal thiolate in the polymer and at this point (the end of the induction period), the rate of photooxidation reverts to that of the polymer containing the uncomplexed transition metal ion. 

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