Benzoyl peroxide

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Benzoyl peroxide
Skeletal formula
Ball-and-stick model
Names
IUPAC name
dibenzoyl peroxide
Other names
benzoyl peroxide, benzoperoxide
Identifiers
ATC codeD10AE01
CAS number94-36-0 YesY
ChEMBLChEMBL1200370 N
ChemSpider6919 YesY
EC-number202-327-6
Jmol-3D imagesImage
KEGGD03093 YesY
PubChem7187
RTECS numberDM8575000
UNIIW9WZN9A0GM YesY
Properties
C14H10O4
Molar mass242.23 g·mol−1
Appearancecolourless solid
Density1.334 g/cm3
Melting point103 to 105 °C (217 to 221 °F; 376 to 378 K) decomposes
poor
Pharmacology
topical
Licence dataUS
Legal statusUSOTC
USC
Hazards
MSDSExternal MSDS
Main hazardsirritant, explosive[1]
EU Index617-008-00-0
EU classificationExplosive (E)
Irritant (Xi)
R-phrasesR3, R7, R36, R43
S-phrases(S2), S3/7, S14, S36/37/39
NFPA 704
Flash point80 °C; 176 °F; 353 K[1]
80 °C (176 °F; 353 K)
US health exposure limits (NIOSH):
TWA 5 mg/m3[1]
TWA 5 mg/m3[1]
1500 mg/m3[1]
Supplementary data page
Refractive index (n),
Dielectric constantr), etc.
Thermodynamic
data
Phase behaviour
solid–liquid–gas
UV, IR, NMR, MS
Except where noted otherwise, data is given for materials in their standard state (at 25 °C (77 °F), 100 kPa)
 N verify (what isYesY/N?)
Infobox references
 
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Benzoyl peroxide
Skeletal formula
Ball-and-stick model
Names
IUPAC name
dibenzoyl peroxide
Other names
benzoyl peroxide, benzoperoxide
Identifiers
ATC codeD10AE01
CAS number94-36-0 YesY
ChEMBLChEMBL1200370 N
ChemSpider6919 YesY
EC-number202-327-6
Jmol-3D imagesImage
KEGGD03093 YesY
PubChem7187
RTECS numberDM8575000
UNIIW9WZN9A0GM YesY
Properties
C14H10O4
Molar mass242.23 g·mol−1
Appearancecolourless solid
Density1.334 g/cm3
Melting point103 to 105 °C (217 to 221 °F; 376 to 378 K) decomposes
poor
Pharmacology
topical
Licence dataUS
Legal statusUSOTC
USC
Hazards
MSDSExternal MSDS
Main hazardsirritant, explosive[1]
EU Index617-008-00-0
EU classificationExplosive (E)
Irritant (Xi)
R-phrasesR3, R7, R36, R43
S-phrases(S2), S3/7, S14, S36/37/39
NFPA 704
Flash point80 °C; 176 °F; 353 K[1]
80 °C (176 °F; 353 K)
US health exposure limits (NIOSH):
TWA 5 mg/m3[1]
TWA 5 mg/m3[1]
1500 mg/m3[1]
Supplementary data page
Refractive index (n),
Dielectric constantr), etc.
Thermodynamic
data
Phase behaviour
solid–liquid–gas
UV, IR, NMR, MS
Except where noted otherwise, data is given for materials in their standard state (at 25 °C (77 °F), 100 kPa)
 N verify (what isYesY/N?)
Infobox references
Tube of Basiron, a water-based 5% benzoyl peroxide preparation for the treatment of acne.

Benzoyl peroxide (BPO) /ˈbɛnzɔɪl pəˈrɒksd/ is an organic compound in the peroxide family. It consists of two benzoyl groups bridged by a peroxide link. Its structural formula is [C6H5C(O)]2O2. It is one of the most important organic peroxides in terms of applications and the scale of its production. Benzoyl peroxide is used as an acne treatment, for improving flour, for bleaching hair and teeth, for cross-linking polyester resins, and many other uses.

It is on the World Health Organization's List of Essential Medicines, a list of the most important medication needed in a basic health system.[2]

Uses[edit]

Most benzoyl peroxide is used as a radical initiator to induce polymerizations.[3] Other major applications include its antiseptic and bleaching properties.

Acne treatment[edit]

Benzoyl peroxide is effective for reducing the number and severity of acne lesions. BPO has a bactericidal effect on Propionibacterium acnes bacteria associated with acne and does not induce antibiotic resistance.[4][5] It may be combined with salicylic acid, sulfur, erythromycin or clindamycin (antibiotics), and adapalene (a synthetic retinoid). Two common combination drugs include benzoyl peroxide/clindamycin and adapalene/benzoyl peroxide, a unique formulation considering most retinoids are deactivated by peroxides. Combination products such as benzoyl peroxide/clindamycin and benzoyl peroxide/salicylic acid appear to be slightly more effective than benzoyl peroxide alone for the treatment of acne lesions.[5]

Benzoyl peroxide for acne treatment is typically applied to the affected areas in gel or cream form, in concentrations of 2.5% increasing through 5%, and up to 10%.[4] There is no strong evidence to support the idea that higher concentrations of benzoyl peroxide are more effective than lower concentrations.[4]

Benzoyl peroxide commonly causes initial dryness and sometimes irritation, although the skin develops tolerance 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.[citation needed] It is sensible to apply the lowest concentration and build up as appropriate. Once tolerance is achieved, increasing the quantity or concentration and gaining tolerance at a higher level may give better subsequent acne clearance.[6] Irritation can also be reduced by avoiding harsh facial cleansers and wearing sunscreen prior to sun exposure.[6]

Other uses[edit]

Other common uses for benzoyl peroxide include

In the U.S., the typical concentration for benzoyl peroxide is 2.5% to 10% for both prescription and over-the-counter drug preparations that are used 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 fabrics 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.[9]

Side effects[edit]

Concentrated benzoyl peroxide is potentially explosive,[10] and can cause fires without external ignition. The hazard is acute for the pure material, and for this reason, the compound is generally used as a solution or a paste. For example, cosmetics contain only a small percent of benzoyl peroxide and pose no explosion risk.

Studies have highlighted the carcinogenic potential of benzoyl peroxide. A 1981 study from the journal Science concluded that "caution should be recommended in the use of this and other free radical-generating compounds".[11]

In a 1977 study using a human maximization test, 76% of subjects acquired a contact sensitization to benzoyl peroxide. Formulations of 5% and 10% were used.[12]

Synthesis, structure and physical properties[edit]

Benzoyl peroxide was the first organic peroxide prepared by intentional synthesis. It was prepared by treating benzoyl chloride with barium peroxide,[13] a reaction that probably follows this equation:

2 C6H5C(O)Cl + BaO2 → [C6H5C(O)]2O2 + BaCl2

Benzoyl peroxide is usually prepared by treating hydrogen peroxide with benzoyl chloride.

The oxygen-oxygen bond in peroxides is weak. Thus benzoyl peroxide readily undergoes homolysis (symmetrical fission), forming free radicals:

[C6H5C(O)]2O2 → 2 C6H5CO2

The symbol indicates that the products are radicals; i.e., they contain at least one unpaired electron. Such species are highly reactive. The homolysis is usually induced by heating. The half-life of benzoyl peroxide is one hour at 92 °C. At 131 °C, the half-life is one minute.[14]

Benzoyl peroxide breaks down in contact with skin, producing benzoic acid and oxygen, neither of which is significantly toxic.[15] 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 can be corrosive due to its oxidizing properties, but decomposes to form water and oxygen. Sodium hypochlorite (commonly known as "bleach") also shares these properties, but disproportionates to form harmless products such as sodium chloride.[citation needed]

References[edit]

  1. ^ a b c d e NIOSH Pocket Guide to Chemical Hazards 0052
  2. ^ "WHO Model List of EssentialMedicines". World Health Organization. October 2013. Retrieved 22 April 2014. 
  3. ^ Klenk, Herbert; Götz, Peter H.; Siegmeier, Rainer; Mayr, Wilfried (2005), "Peroxy Compounds, Organic", Ullmann's Encyclopedia of Industrial Chemistry, Weinheim: Wiley-VCH, doi:10.1002/14356007.a19_199 
  4. ^ a b c Simonart T (December 2012). "Newer approaches to the treatment of acne vulgaris". Am J Clin Dermatol 13 (6): 357–64. doi:10.2165/11632500-000000000-00000. PMID 22920095. 
  5. ^ a b Seidler EM, Kimball AB (July 2010). "Meta-analysis comparing efficacy of benzoyl peroxide, clindamycin, benzoyl peroxide with salicylic acid, and combination benzoyl peroxide/clindamycin in acne". J Am Acad Dermatol 63 (1): 52–62. doi:10.1016/j.jaad.2009.07.052. PMID 20488582. 
  6. ^ a b al.], edited by Brian K. Alldredge ... [et (2013). Applied therapeutics : the clinical use of drugs. (10th ed. ed.). Baltimore: Wolters Kluwer Health/Lippincott Williams & Wilkins. p. 949. ISBN 978-1609137137. 
  7. ^ http://www.degaroute.com/sites/dc/Downloadcenter/Evonik/Product/DEGAROUTE/en/Degaroute%20Brosch%C3%BCre.pdf
  8. ^ Stevens, Cynthia. "Oxy10 for vinyl stains. Benzoyl Peroxide removes stain from Vinyl. Restore Dolls". Prilly Charmin Dolls. Retrieved 9 February 2015. 
  9. ^ Bojar, RA; Cunliffe, William; Holland, KT (1995), "The short-term treatment of acne vulgaris with benzoyl peroxide: effects on the surface and follicular cutaneous microflora.", Br J Dermatol 132: 204–8, doi:10.1111/j.1365-2133.1995.tb05014.x, PMID 7888356 
  10. ^ Cartwright, Hugh (17 March 2005). "Chemical Safety Data: Benzoyl peroxide". Oxford University. Retrieved 13 August 2011. 
  11. ^ "Skin tumor-promoting activity of benzoyl peroxide, a... [Science. 1981] - PubMed - NCBI". Ncbi.nlm.nih.gov. 2012-05-24. Retrieved 2012-09-08. 
  12. ^ Leyden, James J.; Kligman, Albert M. (1977), "Contact sensitization to benzoyl peroxide", Contact Dermatitis 3 (5): 273–75, doi:10.1111/j.1600-0536.1977.tb03674.x 
  13. ^ Brodie, B. C. (1858), "Ueber die Bildung der Hyperoxyde organischer Säureradicale", Justus Liebigs Ann. Chem. 108: 79–83, doi:10.1002/jlac.18581080117 
  14. ^ Li, Hui, III (1998), Synthesis, Characterization and Properties of Vinyl Ester Matrix Resins, Ph.D. Dissertation, University of Vermont, Chapter 2 
  15. ^ Benzoyl peroxide, SIDS Initial Assessment Report, Geneva: United Nations Environment Programme, April 2004 

External links[edit]