Bond Strengths in Vinyl, Allyl, and Ethynyl Hydroperoxides

S Bond Strengths in Vinyl, Allyl, and Ethynyl Hydroperoxides 

Vinyl Hydroperoxides, Effect of Methyl Substitution on Bond Energies  

The bond energy for the C=COO—H is 86.0 kcal mof. The four other vinyl hydroperoxides (trans-CC=COOH, c/5-CC=COOH and C(C)C=COOH and CC=C(C)OOH) have roughly the same ROO—H bond energies 85.9, 86.5, 85.0 and 85.5 kcal mof, respectively. C=C(C)OOH is lower, 84.8 kcal mof. The ROO— H bond energies for all vinylic hydroperoxides in this study vary within a range 84.8 to 86.5 kcal mof, which is within the uncertainty range. 

The calculated CO—OH bond energy, is 23.0 kcal mof in C=COOH and 21.2 kcal mof and 21.7 kcal mof in the trans and cis CC=CO—OH respectively. It is lower, yet, in CC=C(C)OOH (19.3 kcal mof ). These values are more than 20 kcal mof lower than the RO—OH bonds in alkyl hydroperoxides. The weak bond (low stability) in these molecules leads to lifetimes, on the order of seconds at room temperature and much shorter lifetimes under low temperature combustion conditions. We note that the range in bond energies is 

There is one previously reported value of a vinyl hydroperoxide enthalpy, that we are aware of, that of Schlegel et al. [113]. Their data suggest a value for the O—O bond energy of a secondary methyl substituted vinyl hydroperoxide, C=C(C)OOH of 23 kcal mol which is in reasonable agreement with our calculated value for that species, 21.1 kcal mol  

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