Peroxides

Peroxides are a class of chemical compounds characterized by a peroxide linkage, an O−O single bond. They can be broadly grouped into organic peroxides, which have the structure R−O−O−R′ or R−OOH in hydroperoxides, and inorganic peroxides that contain an oxide ion pair such as O2^2−. The O−O bond is generally weaker than many other bonds, making peroxides reactive and often oxidizing.

Common examples include hydrogen peroxide (H2O2), sodium peroxide (Na2O2), and barium peroxide (BaO2) among inorganic peroxides; organic examples include benzoyl peroxide, di-tert-butyl peroxide, and tert-butyl hydroperoxide. Peroxides are typically strong oxidizers; their O−O bond can homolytically cleave to form radicals, driving polymerization and other radical processes. Organic peroxides can initiate polymerization and release heat, and some are shock-sensitive explosives.

Hydrogen peroxide is produced industrially mainly by the anthraquinone process and is a widely used bleaching agent, disinfectant, and oxidant. Inorganic peroxides are prepared by direct reaction of reactive metals with oxygen (for example, 4Na + O2 → 2Na2O2) or by decomposition of precursors; many are used as oxidizers in chemical synthesis, pulp bleaching, and related processes. Organic peroxides serve as radical initiators for polymerization in plastics and rubber manufacture and are also employed as curing agents and, in controlled concentrations, as acne treatments.

Peroxides can decompose violently, especially upon heating, mechanical shock, or catalysis by trace metals. They should be stored away from reducing agents, oils, and metal surfaces; solutions range from household concentrations (about 3%) to industrial concentrations (up to around 30–35% or higher). Proper handling requires separation from incompatible materials and adequate ventilation.