Organic peroxides
The O−O bond of peroxides easily breaks, producing free radicals of the form RO• (the dot represents an unpaired electron).
Thus, organic peroxides are useful as initiators for some types of polymerization, such as the acrylic, unsaturated polyester, and vinyl ester resins used in glass-reinforced plastics.
The dioxetane is unstable and decays spontaneously to carbon dioxide and excited ketones, which release excess energy by emitting light (bioluminescence).
Industrial resins based on acrylic and/or methacrylic acid esters are invariably produced by radical polymerization with organic peroxides at elevated temperatures.
[10] Methyl ethyl ketone peroxide, benzoyl peroxide and to a smaller degree acetone peroxide are used as initiators for radical polymerization of some thermosets, e.g. unsaturated polyester and vinyl ester resins, often encountered when making fiberglass or carbon fiber composites (CFRP), with examples including boats, RV units, bath tubs, pools, sporting equipment, wind turbine blades, and a variety of industrial applications.
Thermoplastic production techniques for many industrial polymerization applications include processes which are carried out in bulk, solution, or suspension type batches.
[12][13] The hazards associated with storage of ethers in air is attributed to the formation of hydroperoxides via the direct albeit slow reaction of triplet oxygen with C-H bonds.
When used for these purposes, the peroxide is highly diluted, so the heat generated by the exothermic decomposition is safely absorbed by the surrounding medium (e.g. polymer compound or emulsion).
A large fire at the Arkema Chemical Plant in Crosby, Texas (USA) in 2017 was caused by the decomposition of various organic peroxides following power failure and subsequent loss of cooling systems.
[14] This occurred due to extreme flooding from Hurricane Harvey, which destroyed main and back-up power generators at the site.
Organoperoxides can be reduced to alcohols with lithium aluminium hydride, as described in this idealized equation: The phosphite esters and tertiary phosphines also effect reduction: Cleavage to ketones and alcohols occurs in the base-catalyzed Kornblum–DeLaMare rearrangement, which involves the breaking of bonds within peroxides to form these products.
For example, artemisinin and its derivatives, such as artesunate, possess the most rapid action of all current drugs against falciparum malaria.
[19] Here peroxides, hydroperoxides or peracids oxidize the added potassium iodide into iodine, which reacts with starch producing a deep-blue color.
[25] For safety reasons, peroxidic compounds are stored in a cool, opaque container, as heating and illumination accelerate their chemical reactions.
Small amounts of peroxides, which emerge from storage or reaction vessels are neutralized using reducing agents such as iron(II) sulfate.
Safety measures in industrial plants producing large amounts of peroxides include the following: 1) The equipment is located within reinforced concrete structures with foil windows, which would relieve pressure and not shatter in case of explosion.
