15538-83-7Relevant articles and documents
A Novel Reaction of HCrO4- with PH2O2-, Induced by Molecular Oxygen, Forming Peroxodiphosphate Ions in an Aqueous Solution
Kimura, Masaru,Takahashi, Aki,Kayanoki, Hiroko,Sakata, Tomomi,Tsukahara, Keuiichi
, p. 2699 - 2702 (1997)
The chromate (VI) ion HCrO4- at pH 2-4 was not appreciably reduced by the phosphinate ion PH2O2- in the absence of molecular oxygen (O2), but was reduced in the presence of O2, forming peroxodiphosphate ions (denoted by PDP and meaning all forms of P2O84-, HP2O83- etc.) in much higher concentrations than those of the added chromate(VI). Both the rates of the chromate decay and the PDP formation increased with decreasing pH. When the chromate(VI) ion disappeared completely, PDP formation stopped and its concentration remained constant. However, such PDP once formed in the presence of O2 began to decompose after the solution was saturated with N2 gas; its decomposition ceased again when the solution was again saturated with air. Such behaviors are discussed while presenting the reaction mechanisms.
Formation of Peroxodiphosphate by the Copper(II)-Catalyzed Oxidation Reaction of the Phosphinate Ion by the Molecular Oxygen. Kinetics and Mechanisms in Aqueous Solutions
Kimura, Masaru,Seki, Kyouko,Horie, Hitomi,Tsukahara, Keiichi
, p. 613 - 617 (2007/10/03)
It was found that peroxodiphosphate ions (denoted by PDP and meaning all forms of P2O84-, HP2O83-, HP2O823-, etc.) were formed by the oxidation of the phosphinate ion (PH2O2-) by molecular oxygen (O2) using trace amounts of the copper(II) ion as a catalyst in aqueous solutions. The formation rate was dependent on the acidity being maximum at around pH 3.5, and was inhibited by the presence of radical scavengers or a complex-forming substance of ethylene-diaminetetraacetic acid (EDTA). The formation of PDP was not observed when ions such as IrIV and CeIV were used in place of the copper(II) ion. Thus, this reaction is specific only for the copper(II) ion, which can be easily reduced to Cu+ by the phosphinate ion, where the reduced species are capable of reacting with molecular oxygen to efficiently produce the superoxide of O-.2 or HO.2. After some PDP had been formed in the presence of air or oxygen, if the reacting solution was changed to be anaerobic by bubbling nitrogen through the solution, the PDP began to decompose according to the first-order rate law with respect to the concentrations of PDP. The kinetics and mechanisms for not only the formation, but also the decomposition of PDP, are presented.
