Benzoyl peroxide Totally Explained

Everything about Benzoyl Peroxide totally explained

,, | SPhrases=,,, | Autoignition=80°C| RTECS=DM8575000}}}} Benzoyl peroxide is a chemical in the organic peroxide family. It consists of two benzoyl groups (benzaldehyde with the H of aldehyde removed) joined by a peroxide group. Acceptable condensed structural formulae would include C₆H₅-COO-OOC-C₆H₅, PhCO-O-O-COPh, and (PhCO)₂O₂. It is often abbreviated Bz₂O₂.

Uses

Benzoyl peroxide is used as a radical initiator. Homolytic cleavage of the weak oxygen-oxygen bond forms benzoyl free radicals which trigger further reactions.
Jack Breitbart of Revlon laboratories first developed benzoyl peroxide's use for treating acne 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 dyeing hair, and as an active ingredient in teeth whitening systems. It is also used in the preparation of flour, and can be used as an initiator and catalyst for polyester thermoset resins (as an alternative to the much more hazardous methyl ethyl ketone peroxide).

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, 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 and over the counter use in treatment for acne. Higher concentrations are used for hair bleach and teeth whitening. Benzoyl peroxide, like most peroxides, is a powerful bleaching 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 and oxygen, neither of which are significantly toxic.

Synthesis

Benzoyl peroxide is usually prepared by reacting sodium peroxide with benzoyl chloride to give benzoyl peroxide and sodium chloride. ť 2 PhCOCl + Na₂O₂ → (PhCO)₂O₂ + 2 NaCl

Decomposition

The half-life of benzoyl peroxide is one hour at 92°C. At 131°C, the half-life is one minute.

Further Information

Get more info on 'Benzoyl Peroxide'.

External Link Exchanges

Do you know how hard it is to get a link from a large encyclopaedia? Well we're different and will prove it. To get a link from us just add the following HTML to your site on a relevant page:

<a href="http://benzoyl_peroxide.totallyexplained.com">Benzoyl peroxide Totally Explained</a>

Then simply click through this link from your web page. Our crawlers will verify your link, extract the title of your web page and instantly add a link back to it. If you like you can remove the words Totally Explained and embed the link in article text.
As long as your link remains in place, we'll keep our link to you right here. Please play fair - our crawlers are watching. Your site must be closely related to this one's topic. Any kind of spamming, dubious practises or removing the link will result in your link from us being dropped and, potentially, your whole site being banned.