Hydrogen peroxide 0-0 bond dissociation energy

Key Words Lewis acid adducts, Radical oxidations, Epoxidation, Hydrogen peroxide, Bond dissociation energy, Catalyst durability, Methyltrioxorhenium, Cross-bridged cyclam, Mn(IV), Late transition metal. Propylene oxide. Titanium silicalite (TS-1) catalyst, Ethylanthrahydroquinone/H2 process, Polyoxometallates, Mn(IV) catalyst. Hydrogen abstraction. Rebound mechanism, Isotopic label, t-BuOOH, Peroxide adduct. 2008 Elsevier B.v. 

The bond dissociation energy of hydrogen peroxide has been accurately predicted by high-level ah initio theory16. It was disclosed very early that Hartree-Fock theory, in the absence of electron-correlation correction, simply cannot be applied to problems involving 0—0 bond dissociation. For example, the predicted 0—0 bond energy in peroxyformic acid is only 1.0 kcalmol-1 by Hartree-Fock theory, whereas at the... 

The reported Arrhenius parameters for the diacyl peroxides appear quite reasonable. For example, the heat of formation of the acetoxy radical deduced from the observed activation energies is A/f (CH3COO-) = —49.7 kcal.mole . This gives a bond dissociation energy of the acidic hydrogen in acetic acid of >(CH3C02 -H) = 106 kcal.mole , very comparable to (O-H) bond dissociation energies in alcohols, -factors are also very reasonable. Since two internal rotations become partially restricted in the transition state as shown below... 

Hydroxy and alkoxy radicals, obtained from hydrogen peroxide or alkyl peroxides were used 57,58), Bond dissociation energies and polar effects preferentially promote the hydrogen abstraction from the C—H bond. However a hydrogen abstraction from the N—H bond would result without consequences because it would give rise to an electrophilic nitrogen-centered radical, unreactive towards proto-nated heteroaromatic bases. 

The mean O-H bond dissociation energy is hydrogen peroxide, defined as half the standard energy of the reaction... 

Employing the latter value as the energy of the O—H bond we obtain for the dissociation of hydrogen peroxide into two peroxide groups H2O2 = 20H d// = 56 6 kcals... 

The central O—O bond in hydrogen peroxide has a dissociation energy of 17,350 cm-1, an amount of energy which can be more than achieved by excitation of the v = 6 overtone of an O—H bond. As a consequence, there have been a number of experimental and theoretical studies of overtone induced dissociation of hydrogen peroxide. 

---