Benzoyl peroxide

Benzoyl Peroxide

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Benzoyl peroxide

Benzoyl peroxide is a chemical in the organic peroxide

Organic peroxide

Organic peroxides are organic compounds containing the peroxide functional group . If the R' is hydrogen, the compound is called an organic hydroperoxide....
family. It consists of two benzoyl groups (benzoic acid

Benzoic acid

Peroxide

A peroxide is a compound containing an oxygen-oxygen chemical bond. The simplest stable peroxide is hydrogen peroxide. Superoxides, dioxygenyls, ozones and ozonides compound are considered separately....
group. Acceptable condensed structural formula

Structural formula

The structural formula of a chemical compound is a graphical representation of the molecular structure showing how the atoms are arranged. The chemical bonding within the molecule is also shown, either explicitly or implicitly....
e would include C₆H₅-COO-OOC-C₆H₅, PhCO-O-O-COPh, and (PhCO)₂O₂.

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Encyclopedia

Benzoyl peroxide is a chemical in the organic peroxide

Organic peroxide

Benzoic acid

Peroxide

Structural formula

Structure and properties

The half-life

Half-life

The half-life of a quantity whose value decreases with time is the interval required for the quantity to decay to half of its initial value. The concept originated in describing how long it takes atoms to undergo radioactive decay but also applies in a wide variety of other situations....
of benzoyl peroxide is one hour at 92°C. At 131°C, the half-life is one minute.

Synthesis

Benzoyl peroxide is usually prepared by reacting sodium peroxide

Sodium peroxide

Sodium peroxide, Na2O2, is the normal product when sodium is burned. It is a strong oxidizer....
with benzoyl chloride

Benzoyl chloride

Benzoyl chloride, also known as benzenecarbonyl chloride, is a colourless, fuming liquid, C6H5COCl, with an irritating odour....
to give benzoyl peroxide and sodium chloride

Sodium chloride

Sodium chloride, also known as common salt, table salt, or halite, is a chemical compound with the chemical formula SodiumChlorine....
.

2 PhCOCl + Na₂O₂ ? (PhCO)₂O₂ + 2 NaCl

Uses

Benzoyl peroxide is used as a radical initiator

Radical initiator

In chemistry, radical initiators are substances that can produce radical under mild conditions and promote radical polymerization reactions. These substances generally possess weak bonds—bonds that have small bond dissociation energy....
. Homolytic cleavage of the weak oxygen-oxygen bond forms benzoyl free radicals

Radical (chemistry)

In chemistry, radicals are atoms, molecules or ions with unpaired electrons on an otherwise open shell configuration. These unpaired electrons are usually highly chemical reaction, so radicals are likely to take part in chemical reactions....
which trigger further reactions.

Acne treatment

Jack Breitbart of Revlon

Revlon

Revlon is an American cosmetics company....
laboratories first developed benzoyl peroxide's use for treating acne

Acne

Acne is a group of skin rashes that have different causes.* Acne vulgaris - most commonly experienced around puberty, typically of the face and shoulders/chest...
in the 1920s. It is typically placed over the affected areas in gel or cream form, in concentrations of 2.5% increasing through the usually effective 5% to up to 10%. Research suggests that 5 and 10% concentrations are not significantly more effective than 2.5% and 2.5% is usually better tolerated. It commonly causes initial dryness and sometimes irritation, although skin tolerance usually occurs after a week or so. A small percentage of people are much more sensitive to it and liable to suffer burning, itching, peeling and possibly swelling. It is sensible to apply the lowest concentration and build up as appropriate. Once tolerance is achieved, increasing the quantity or concentration a second time and gaining tolerance at a higher level usually gives better subsequent acne clearance. Benzoyl peroxide works as a peeling agent, increasing skin turnover and clearing pores, thus reducing the bacterial count there as well as directly as an antibacterial.

Other common uses for benzoyl peroxide include dying hair, and as an active ingredient in teeth whitening systems. It is also used in the preparation of flour

Flour

Flour is a powder made of cereal grains. It is the main ingredient of bread, which is a staple food for many civilizations, making the availability of adequate supplies of flour a major economic and political issue at various times throughout history....
, and can be used as an initiator

Initiator

An initiator can refer to:* Pyrotechnic initiator, a device containing a pyrotechnic composition used primarily to ignite other, more difficult to ignite materials...
and catalyst for polyester

Polyester

Polyester is a category of polymers which contain the ester functional group in their main chain. Although there are many polyesters, the term "polyester" as a specific material most commonly refers to polyethylene terephthalate ....
thermoset resins (as an alternative to the much more hazardous methyl ethyl ketone peroxide

Methyl ethyl ketone peroxide

Methyl ethyl ketone peroxide is an organic peroxide, a high explosive similar to acetone peroxide. MEKP is a colorless, oily liquid whereas acetone peroxide is a white powder at Standard conditions for temperature and pressure; MEKP is slightly less sensitive to shock and temperature, and more stable in storage....
).

Adverse effects

In a 1977 study using a human maximization test, 76% of subjects acquired a contact sensitation to benzoyl peroxide. Formulations of 5% and 10% were used.

Safety

Pure benzoyl peroxide is highly flammable, explosive, toxic and a possible tumor promoter and may act as a mutagen

Mutagen

In biology, a mutagen is a physical or chemical agent that changes the genetic information of an organism and thus increases the frequency of mutations above the natural background level....
, and should be handled with care.

Diluted in an ointment, benzoyl peroxide is used as an acne treatment and the following precautions and claims pertain to this use. Attention should be paid to the safety directions provided when purchased.

In the United States, the typical concentration for benzoyl peroxide is 2.5% to 10% for both prescription

Prescription drug

A prescription drug is a medication that is regulated by legislation to require a medical prescription before it can be obtained. The term is used to distinguish it from over-the-counter drugs which can be obtained without a prescription....
and over the counter

Over-the-counter drug

Over-the-counter drugs are medications that may be sold to a customer without a medical prescription. The term "over-the-counter" is somewhat counter-intuitive, since these items can often be found on the shelves of stores and bought like any other packaged product in some countries in contrast to prescription drug which are more likely to l...
use in treatment for acne. Higher concentrations are used for hair bleach and teeth whitening. Benzoyl peroxide, like most peroxides, is a powerful bleach

Bleach

A bleach is a chemical that removes colors or whitens, often via oxidation. Common chemical bleaches include household "chlorine bleach", a solution of approximately 3?6% sodium hypochlorite , and "oxygen bleach", which contains hydrogen peroxide or a peroxide-releasing compound such as sodium perborate, sodium percarbonate, sodium persulfat...
ing agent. Contact with fabric (including clothing and bed linens) or hair can cause permanent color dampening almost immediately. Even secondary contact can cause bleaching. For example, contact with a towel that has been used to wash off benzoyl peroxide-containing hygiene products.

Benzoyl peroxide breaks down in contact with skin, producing benzoic acid

Benzoic acid

Benzoic acid, C7H6O2 , is a colorless crystalline solid and the simplest aromatic carboxylic acid. The name derived from gum benzoin, which was for a long time the only source for benzoic acid....
and oxygen, neither of which is significantly toxic. It is important to note that the safety of the decomposition products does not mean that the substance itself is safe, as it is benzoyl peroxide's action as an oxidizing agent that is of importance. Hydrogen peroxide is corrosive, toxic and carcinogenic, but decomposes to form water and oxygen. Sodium hypochlorite (bleach) also shares these properties, but decomposes to form harmless products such as sodium chloride.

External links

IARC
IARC

IARC may refer to:* International Aerial Robotics Competition* International Agency for Research on Cancer* International Arctic Research Center...
Monograph ""