P Bromobenzoyl peroxide

A mixture of 35 g. (0.17 mole) of p-bromobenzoic acid (p. 39) and 36 g. (0.17 mole) of phosphorus pentachloride is warmed on a steam bath until there is no more visible evidence of reaction. The resulting mixture is distilled under reduced pressure. The p-bromo-benzoyl chloride is collected at 136-138°/20 mm. and is obtained in 92% yield. The product solidifies in the receiver. 

A solution of 8.5 g. (0.04 mole) of p-bromobenzoyl chloride (p. 41) in 10 ml. of benzene is added slowly with vigorous stirring to a mixture of 5 g. of sodium peroxide and 50 ml. of ice-cold water. The precipitated white solid is removed by filtration and recrystallized from methanol to give 5.5 g. (71%) of p-bromobenzoyl peroxide, m.p. 143.5° dec. 

Organic peroxides should always be handled with adequate protection against possible explosive decomposition. 

A mixture of 210 g. (0.95 mole) of l-bromo-2-methylnaphthalene (p. 51), 160 g. (0.90 mole) of N-bromosuccinimide (p. 59), 1 g. of benzoyl peroxide, and 250 ml. of carbon tetrachloride is refluxed for 2.5 hours. Carbon tetrachloride (250 ml.) is added, and the warm mixture is filtered. The solid residue is washed several times with fresh carbon tetrachloride. The combined filtrate is concentrated and cooled, and the precipitated product is filtered off. There is obtained 230 g. (85%) of l-bromo-2-bromomethylnaphthalene melting at 103.5-105.5°. 

Marvel, Johnston, Meier, Mastin, Whitson, and Himel, J. Am. Cherq. Soc., 66, 916 (1944). 

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Bartlett and co-workers concluded that addition to the nitro group also occurs. Price and Read found that several m-dinitrobenzene molecules were combined with the polymer for each fragment from the p-bromobenzoyl peroxide used as initiator in the retarded polymerization of styrene. They inferred that the radical corresponding to IV transfers its hydrogen atom to a molecule of styrene as follows ... 

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