Peroxides and Peroxide Compounds, Organic Peroxides

Abstract Organic peroxides are compounds possessing one or more oxygen–oxygen bonds that are thermally and photolytically sensitive to facile homolytic cleavage. Thermal decomposition rates are affected by the structure of the organic peroxide and the decomposition conditions. The initially formed free radicals from the oxygen–oxygen bond homolysis are reactive intermediates which quickly undergo a variety of subsequent reactions to form stable products. Thermolysis of organic peroxides is used commercially to initiate free‐radical reactions, eg, halogenation, vinyl monomer polymerization, unsaturated resin cure, polyolefin cross‐linking and rheology modification. Many organic peroxides also undergo reactions in which free radicals are not involved, eg, heterolyses, hydrolyses, reductions, and rearrangements. This article reviews the physical and chemical properties, synthetic methods, and the principal commercial uses of organic peroxides of the following classes: hydroperoxides, dialkyl peroxides, α‐oxygen‐substituted hydroperoxides and dialkyl peroxides, ozonides, peroxyacids, diacyl peroxides, and alkyl peroxyesters. Class discussions cover the broad structural variation that is possible, including organomineral and polymeric derivatives when appropriate. Emphasis is placed on the relationship between peroxide structure and reactivity (thermal stability). Physical hazards associated with organic peroxide manufacture, handling, storage, transportation, and use are discussed. An overview of health hazards associated with handling of organic peroxides is presented.