Chemical Education Today
CLIP, Chemical Laboratory Information Profile “Only when you know the hazards, can you take the necessary precautionary measures.”
Benzoyl Peroxide
(C6H5CO)2O2
CAS No.: 94-36-0
Synonyms: Dibenzoyl peroxide, benzoyl superoxide
Physical Properties
Exposure Limits
White paste (benzoyl peroxide grains in water) Vapor pressure at 20 °C: negligible Melting point: 104 °C Decomposes explosively as it melts.
OSHA PEL: ACGIH TLV:
5 mg/m3 5 mg/m3
Hazardous Characteristics Overall toxicity 2
Flammability 2
Destructive to skin/eye 2
Absorbed through skin? No
Sensitizer? No
Selfreactive? No
Incompatible with: Bases, acids, organic compounds and all other reducing agents*
0: None (or very low); 1: Slight; 2: Moderate; 3: High; 4: Severe. *Reactivity Hazards
Wet benzoyl peroxide is hazardous as described in this CLIP, and especially so when dry or only slightly moist. Benzoyl peroxide reacts violently with many bases and acids (e.g., amines and organic and inorganic acids). It causes fires and explosions when mixed with many organic compounds and with all strong reducing agents. With weaker reducing agents, the reaction can be violent and exothermic. See Bretherick’s Handbook of Reactive Chemical Hazards for details and for other incompatibilities. Cited as known to be or reasonably anticipated to be carcinogenic in NTP-11?
No
Identified as a reproductive toxin in Frazier and Hage, Reproductive Hazards of the Workplace? No
Typical symptoms of acute exposures:
On the skin, inflammation, pain. In the eyes, inflammation, pain, blurred vision. If ingested, abdominal pain, nausea, vomiting. Principal target organ(s) or system(s):
Skin, eyes.
Storage Requirements Store only in waxed paper or polyethylene-lined paper containers that are kept closed and separate from other oxidizing agents in a cool, dry, well-ventilated location protected from direct sunlight and away from acids, alkalies, amines, flammables, combustibles, and other reducing agents. Inspect stored benzoyl peroxide at least once every month to ensure that it is still wet.
Additional Remarks Do not return unused benzoyl peroxide to the container from which it was removed. Instead, treat the unused material as a hazardous waste that must be immediately destroyed. Do not grind benzoyl peroxide or subject it to frictional shock. Keep benzoyl peroxide wet at all times. The dry compound ignites readily and is shock-, heat-, and friction-sensitive. If benzoyl peroxide—wet or dry—is heated when confined, it will decompose explosively; the decomposition products also are explosive.
Notes ReadMe
This Chemical Laboratory Information Profile is not a Material Safety Data Sheet. It is a brief summary for teachers and their students that describes some of the hazards of this chemical as it is typically used in laboratories. On the basis of your knowledge of these hazards and before using or handling this chemical, you need to select the precautions and first-aid procedures to be followed. For that information as well as for other useful information, refer to Material Safety Data Sheets, container labels, and references in the scientific literature that pertain to this chemical. Reproductive Toxins
Some substances that in fact are reproductive toxins are not yet recognized as such. For the best readily available and up-to-date information, refer to “DART/ETIC”. See the TOXNET home page at http://toxnet.nlm.nih.gov/. Note that some of the data in DART/ETIC have not been peer-reviewed. See also Frazier, Linda M.; Hage, Marvin L. Reproductive Hazards of the Workplace; Wiley: New York, 1998; and Shepard, T. H. Catalog of Teratogenic Agents, 9th ed.; Johns Hopkins University Press: Baltimore, MD, 1998. Abbreviations
ACGIH TLV—American Conference of Governmental Industrial Hygienists–Threshold Limit Value. C—Ceiling. CAS—Chemical Abstracts Service. mg/m3—milligrams per cubic meter. NA—Not applicable. NE—Not established. NI—No information. NTP-11—National Toxicology Program, Eleventh Annual Report on Carcinogens. OSHA PEL—Occupational Safety and Health Administration–Permissible Exposure Limit. ppm—parts per million. STEL/C—Short-term exposure limit and ceiling. Prepared by: Jay A. Young
696
Journal of Chemical Education
Date of preparation: December 16, 2004
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Vol. 83 No. 5 May 2006
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www.JCE.DivCHED.org
