Benzoyl peroxide
[CAS# 94-36-0]

Identification

• Classification: API >> Synthetic anti-infective drugs >> Disinfectant antiseptic
• Name: Benzoyl peroxide
• Synonyms: Dibenzoyl peroxide; BPO; Perkadox L
• Molecular Formula: C₁₄H₁₀O₄
• Molecular Weight: 242.23
• CAS Registry Number: 94-36-0
• EC Number: 202-327-6
• SMILES: C1=CC=C(C=C1)C(=O)OOC(=O)C2=CC=CC=C2

Properties

• Density: 1.33 g/mL
• Melting point: 104-106 °C
• Refractive index: 1.534
• Flash point: 176 °F
• Water solubility: Insoluble 0.2 g/100g

Safety Data

• Hazard Symbols: GHS01;GHS02;GHS07 Danger
• Risk Statements: H241-H319-H317
• Safety Statements: P210-P234-P235-P240-P261-P264+P265-P272-P273-P280-P302+P352-P305+P351+P338-P321-P333+P317-P337+P317-P362+P364-P370+P380+P375[+P378]-P391-P403-P410-P411-P420-P501

Hazard Classification

Hazard	Class	Category Code	Hazard Statement
Eye irritation	Eye Irrit.	2	H319
Skin sensitization	Skin Sens.	1	H317
Organic peroxides	Org. Perox.	B	H241
Acute hazardous to the aquatic environment	Aquatic Acute	1	H400
Chronic hazardous to the aquatic environment	Aquatic Chronic	1	H410
Skin sensitization	Skin Sens.	1B	H317
Organic peroxides	Org. Perox.	C	H242
Self-reactive substances or mixtures	Self-react.	B	H241
Chronic hazardous to the aquatic environment	Aquatic Chronic	2	H411
Specific target organ toxicity - single exposure	STOT SE	3	H335
Self-reactive substances or mixtures	Self-react.	C	H242
Organic peroxides	Org. Perox.	D	H242
Acute toxicity	Acute Tox.	4	H302

Discovery and Applications

Benzoyl peroxide (BPO), best known for its use in acne treatment, plays a variety of roles in medicine and industry due to its antimicrobial properties and ability to promote skin exfoliation. Benzoyl peroxide was first synthesized in the mid-19th century by reacting benzoyl chloride with barium peroxide. It was initially noted for its explosiveness, but its medicinal potential was not realized until later. By the 1920s, it became clear that BPO had significant antimicrobial effects. Its ability to produce free radicals that attack bacterial cell walls laid the foundation for its use in dermatology, especially for acne treatment.

The applications of BPO are varied and cover the fields of dermatology, medicine, and industry. The main use of BPO is in topical acne treatment. Its antimicrobial effects reduce the number of Propionibacterium acnes on the skin, which causes acne to develop. In addition, BPO helps to remove dead skin cells and excess oil from pores, reduce inflammation, and prevent new acne lesions. Its effectiveness has led to its inclusion in many over-the-counter and prescription acne medications.

In addition to dermatology, BPO is used as a bleaching agent in various industries for bleaching hair, flour, and even certain plastics. Its strong oxidizing properties make it effective in breaking down color-causing compounds in these materials.

In polymer chemistry, BPO is used as a free radical initiator for polymerization reactions. Its ability to break down into free radicals at relatively low temperatures makes it useful in the synthesis of various plastics and resins.

While BPO is generally safe when used as directed, it can cause skin irritation or dryness. It is critical for users to start with lower concentrations and gradually increase the concentration to allow the skin to acclimate. Care should also be taken to avoid contact with hair and clothing, as BPO can bleach these materials.

References

2010. Polymethacrylate Microparticles Gel for Topical Drug Delivery. Pharmaceutical Research, 27(10).
DOI: 10.1007/s11095-010-0212-9

2005. Simultaneous sodium lauryl sulphate testing improves the diagnostic validity of allergic patch tests. Results from a prospective multicentre study of the German Contact Dermatitis Research Group (Deutsche Kontaktallergie-Gruppe, DKG). The British journal of dermatology, 152(4).
DOI: 10.1111/j.1365-2133.2004.06465.x

2003. Functionalization of Carbon Nanotubes by Free Radicals. Organic Letters, 5(6).
DOI: 10.1021/ol0342453