Peroxycarbonate formation

Another possibility for oxygen dissolution is peroxycarbonate formation ... 

The deoxygenation of peroxycarbonates (53) with phosphines and phosphites has been examined. Reaction with phosphites favours pyrocarbonate formation (Path A) whilst phosphines favour carbonate formation (Path B). Secondary phosphine oxides are oxidized to phosphinic acids by perbenzoic acid. The kinetics of the deoxygenation of hydroperoxides by triphenylphosphine have been examined and the reaction shown to be catalysed by strong acids. ... 

The reaction of C02 with Ir(CH3)CO(02)[P(p-tolyl)3]2 also results in the formation of a peroxycarbonate complex (191) via external attack by carbon dioxide. In this case, however, only gaseous carbon dioxide is required, rather than the more strenuous conditions of liquid C02. This same complex reacts with gaseous carbon monoxide to form the carbonate complex. Labeling experiments demonstrate that the coordinated CO does not participate in the reaction External attack by the added CO is responsible for the reaction (191). Coordinated CO has been shown to react with bound dioxygen, as is seen in Scheme 16. In this case, the chelating triphos ligand obviously has a significant effect on the reactivity (189). 

Formation of Carbon Dioxide Complexes. As mentioned in the introduction, our initial interest in synthesizing the PCy3 complexes was in their potential for binding C02. However, except for the formation of peroxycarbonate and carbonato complexes from IrCl(02)(PCy3)2 (44), which is well-established chemistry for some platinum metal peroxide complexes (42) (but, to our knowledge, not with PCy3 systems), we have not been able to isolate any C02 complexes or even carbonate or bicarbonate species which are formed sometimes in the presence of adventitious water (16). 

HAZARD RISK Dangerous fire hazard explodes on contact with benzoyl peroxide or diisopropyl peroxycarbonate incompatible with acids, acid chlorides, acid anhydrides, chloro-formates, halogens and oxidizing agents thermal decomposition may produce carbon monoxide, carbon dioxide and nitrogen oxides NFPA Code H 3 F 2 R 0. 

Fig. 29. Formation of the manganese peroxycarbonate complex (A) by the direct reaction of peroxycarbonate or (B) by the reaction of the peroxy complex with carbonate.

Peroxycarbonate is a biodegradable bleaching agent. Saha et al [8] reported a method for the production of peroxycarbonate on BDD in IM Na2C03 solution. The current efficiency of the formation of sodium peroxycarbonate was found to depend significantly on the current density, anode material, and electrolyte concentration. The maximum current efficiency for producing sodium peroxycarbonate was 82 % at a current density of 0.05 A cm after 30 min of electrolysis in 1 M Na2C03 solution. 

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