BENZOYL PEROXIDE

Prepared at the 55th JECFA (2000) and published in FNP 52 Add 8 (2000), superseding specifications prepared at the 19th JECFA (1975), published in NMRS 55B (1976) and in FNP 52 (1992). The 7th JECFA (1963) had insufficient data to establish an ADI, but noted that the evidence permitted an estimate of an acceptable level of treatment of 0 - 40 mg/kg of flour for human consumption (conditional acceptance for special purposes: 40-75 mg/kg).

SYNONYMS

Benzoyl superoxide, INS No. 928

DEFINITION

Chemical names

Dibenzoyl peroxide

C.A.S. number

94-36-0

Chemical formula

C₁₄H₁₀O₄

Structural formula

Formula weight

242.23

Assay

Not less than 96.0%

DESCRIPTION

Colourless, crystalline solid having a faint odour of benzaldehyde.

Caution: Benzoyl peroxide is a highly reactive compound and may give rise to explosions

FUNCTIONAL USES

Flour treatment agent

CHARACTERISTICS

IDENTIFICATION

Solubility (FNP 5)

Insoluble in water, slightly soluble in ethanol, soluble in ether

Melting range (FNP 5)

103 - 106^o with decomposition

Decomposition to benzoic acid

To 0.5 g of the sample peroxide add 50 ml of 0.5 N ethanolic potassium hydroxide, heat gradually to boiling and continue boiling for 15 min. Cool and dilute with 200 ml of water. Add sufficient 0.5 N hydrochloric acid to make strongly acidic and extract with ether. Dry the ether solution over anhydrous sodium sulfate, and then evaporate to dryness on a steam bath. The residue of benzoic acid so obtained melts between 121^o and 123^o.

PURITY

Lead

Not more than 2 mg/kg

Determine using an atomic absorption technique appropriate to the specified level. The selection of sample size and method of sample preparation may be based on the principles of the method described in FNP 5, “Instrumental Methods”.

METHOD OF ASSAY

Dissolve about 250 mg of the sample, accurately weighed, in 15 ml of acetone in a 100-ml glass-stoppered bottle. Add 3 ml of 50% (w/v) potassium iodide solution and swirl for 1 min. Titrate immediately with 0.1 N sodium thiosulfate (without addition of starch as an indicator). Each ml of 0.1 N sodium thiosulfate is equivalent to 12.11 mg of C₁₄H₁₀O₄.