Hydrogen Isotope Effects and Mechanism of Aqueous Ozone and Peroxone Decompositions

Abstract

Mechanism of ozone decomposition in aqueous solutions Reaction Rate constants in M, s units Ref.

No Marked Kinetic Isotope Effect in the Peroxone (H2O2/D2O2+O3) Reaction: Mechanistic Consequences

“…[4] These results conclude that the electron-transfer reaction [Eq. (3)] cannot be the rate-determining step, and a hydride transfer reaction [Eq.…”

“…(11)] has been made responsible [4] for the well-established AOP properties of the peroxone process and has been termed a "capped COH radical". [5] However, it is difficult to see how a species that has no free-radical character and only a very low intrinsic lifetime (see below) should have properties similar to that of COH.…”

“…Under the conditions used for the determination of the very high KIE, [4] O 3 is destroyed via a chain reaction [Eq. (12) followed by Eqs.…”

Protonation of Water Clusters Induced by Hydroperoxyl Radical Surface Adsorption

“…[9][10][11][12][13][14] In environmental chemistry, the hydroperoxyl radical is a highly oxidant molecule that reacts by addition to double bonds or by abstracting hydrogen atoms, and it is associated with peroxone chemistry and as a radical in advanced oxidation processes. [15][16][17][18] In the literature, a large amount of research work has been devoted to identify hydrogen-bonded complexes between HO 2 and neutral molecules. The interest in these complexes lies in the high stability of some hydrogen bonds formed by HO 2 (in particular, HO 2 has been shown to be a better proton donor than water).…”

Dihydrogen Trioxide (HOOOH) Is Generated during the Thermal Reaction between Hydrogen Peroxide and Ozone

“…Xu and Goddard [31] have proposed that the reaction proceeds via a planar seven-membered-ring biradical intermediate (with the spin multiplicity of the triplet and singlet states being almost degenerate) to yield HOOOH and 3 O 2 ( Figure 3 and Table 1, entry 5). More recently, to explain hydrogen isotope effects on the reaction kinetics of the peroxone reaction in water, Lesko et al [32] have concluded that HO 3 À , the conjugate base of H 2 O 3 , may be generated from a reaction between the anion of hydrogen peroxide and O 3 ( Table 1, entry 6).…”