Benzoyl peroxide

PROPERTIES

Benzoyl peroxide is colourless, crystalline solid having a faint odour of benzaldehyde. It is insoluble in water, slightly soluble in alcohol, and soluble in chloroform and ether.

It is one of the most important organic peroxides in terms of applications and the scale of its production.

Its reactive properties are a result of the central oxygen-oxygen bond that defines all peroxides.  The peroxide bond cleaves easily (with heating, for example), producing a pair of radicals - highly reactive, neutral chemical structures that have a lone, unpaired electron.

APPLICATIONS

FOOD

BLEACHING/WHITENING AGENT

It is the “peroxide” commonly referred to in tooth whiteners and hair dyes.  It works as a bleaching agent when it attacks the double bond structures that are present in most colored molecules.  By destroying these structures, the molecules can no longer absorb certain wavelengths of visible light, so they appear to have no color.

When benzoyl peroxide is used as a bleaching agent, it reacts with the oxidizable substance present, such as annatto and carotenoid pigments, and is itself converted to benzoic acid in the process. The rate of conversion increases with temperature. For hair bleach and teeth whitening, higher concentrations are used (above 10%).

Benzoyl peroxide can also be used for bleaching flour, whey, cheese, vegetable oils, fats and waxes.

PHARMA

DERMATOLOGIC AGENT

The release of oxygen from benzoyl peroxide provide an important application to use as a topical antibacterial used for burns and as a dermatologic agent in the treatment of acne and poison ivy. It shows drying and desquamative actions that promote evacuation of comedones. It has keratolytic function that promotes keratolysis

Benzoyl peroxide is an antiseptic. It reduces the number of surface skin bacteria, but does not cause bacterial resistance to antibiotics. It also reduces the number of yeasts on the surface of the skin.

Benzoyl peroxide for acne treatment is typically applied to the affected areas in gel or cream form, in concentrations of 2.5% increasing through the usually effective 5% to up to 10%.

It’s used as an oxidizing agent in the treatment of decubital and stasis ulcers.

PLASTIC INDUSTRY

POLYMERAZING INITIATOR AND CATALYST

It is one of the general polymerization and copolymerization initiators for ethylene, vinyl acetate, vinyl chloride, styren, acrylates. It can be used as an initiator and catalyst for polyester thermoset resins. Benzoyl peroxide induced graft polymerization of 2-methyl-5-vinylpyridine onto polyester/wool blend. BPO is used with aniline accelerators or where heat is used to cure the resin.

CHEMICAL SYNTESIS

CATALYST

It is used as a catalyst in oxidation and sulfonation reactions. It is a strong free radical source containing more than 4.9% of active oxygen.