New Jobs:

- Synthetic Chemist (Corteva)

- Scientist (Firmenich)

- Sr Scientist (Amgen)

- Head of Med Chem (Maze)

Latest Internships:

- Marquette University

  (Summer 2020)

- Montana State University

  (Summer 2020)

Benzoyl Peroxide

Other Names:

Dibenzoyl peroxide


General Information:


CAS Number: 94-36-0

Molecular Weight: 242.23 g/mol

Appearance: Colorless, crystalline solid

Melting Point: 105 C

Benzoyl peroxide is commonly used in organic chemistry as a radical initiator. It is an organic peroxide that readily undergoes homolysis to form free radicals. The O-O bond in benzoyl peroxide is relatively weak and can undergo homolysis when exposed to sufficient light or heat. Another common radical initiator is Azobisisobutyronitrile (AIBN).

Common Uses:

Radical initiator for benzylic and allylic brominations

Procedure excerpt:

To a solution of the SM (261 mg, 1.00 mmol) in dry CCl4 (5 mL) in a 10 mL microwave vial was added benzoyl peroxide (12 mg, 0.05 mmol), followed by NBS . . .

[full procedure]


Benzoyl peroxide is potentially explosive, especially in pure form. For this reason, benzoyl peroxide is generally purchased commercially as a solid, wet with 25-30% H2O.


1) Patent Reference: WO2012112946, page 165, (11.2 MB)

2) Wikipedia: Benzoyl peroxide (link)

3) Luperox A75, Benzoyl peroxide (link)

4) L13174 Benzoyl peroxide, 97% (dry wt.), wet with 25% water (link)