Chemical Bond Energies of Organic Peroxides: From CHOOCH to High-Molecular-Weight Industrially Significant Compounds.

Peroxides are of some importance in a number of industrial areas, as well as in atmospheric and low-temperature combustion chemistries. Although there are some organic peroxides that are powerful explosives, such as hexamethylene triperoxide diamine, their principal use is as initiators in polymerization reactions in the plastics and rubber industries since the O-O bond is easily cleaved to generate two reactive free radicals. This gives rise to concern about safety issues in both the manufacture of and the deployment of these compounds since they are strong oxidizers. A measure of these safety concerns can be achieved by determining the chemical bond energy or bond dissociation energy (BDE) for the following process: R-O-O-R' → RO + R'O since those with very weak O-O bonds are most likely to be problematic. We have used the midlevel model chemistry G4 to compute the BDE of a number of organic peroxides ranging from the simplest dialkyl peroxide to diacyl, peroxy ester, and peroxycarbonate peroxides. In addition, we have used much higher levels of theory to benchmark the chemical bond energy of dimethyl peroxide in the expectation that this will anchor all future determinations.