Sodium benzoylperoxide

In a 5-I. round-bottom flask, fitted with an efficient mechanical stirrer and surrounded by an ice-salt mixture, is placed a solution of 121 g. (0.5 mole) of pure dry finely-powdered benzoylperoxide (m.p. 104°) (Note 1) in about 1.51. of dry toluene. The temperature should be below —5°. A solution of sodium ethylate, prepared by dissolving 23 g. (1 mole) of sodium in 500 cc. of absolute alcohol, and cooled to o°, is introduced from a separatory funnel while the mixture is vigorously stirred. This operation should not require more than eight or ten minutes. The liquid whitens and thickens considerably on account of the formation of sodium benzoylperoxide. 

After the sodium ethylate has been added, the sodium benzoylperoxide is dissolved by pouring 2 1. of ice water into the flask, while continuing the stirring and keeping the mixture cold (Note 2). When there remains no more than a trace of sodium benzoylperoxide, as evidenced by the fact that addition of a small quantity of ice water produces no further clarification, the toluene layer is separated in a previously cooled separatory funnel. The aqueous solution is extracted with ether which takes up the ethyl benzoate, the ether is separated, and the... 

Hibbert and Burt dissolved the benzoylperoxide in dry ether, cooled to — 50 and added the calculated amount of a 10 per cent sodium ethylate solution, maintaining the low temperature during the procedure. Sufficient ice water was added to give a clear solution, the ether containing the ethyl benzoate separated and the aqueous sodium benzoylperoxide solution added slowly with stirring to twice the necessary amount of cold 20 per cent sulfuric acid (reaction mixture always at o°). The oily layer of benzoylhydroperoxide was then extracted three times with chloroform and the extract dried over anhydrous sodium sulfate. 

It seems to the checkers that if any free alkali were present with the sodium benzoylperoxide this would certainly be neutralized first when acid is added before any free benzoylhydroperoxide is formed. At any rate the yields by both procedures were excellent. 

The benzoylperoxide used was analyzed by dissolving r g. in 25 cc. of dry ether and adding 2 cc. of 5 per cent sodium ethylate solution, keeping the temperature below — 50. The ether solution was extracted with exactly 100 cc. of cold water and an aliquot part of the aqueous extract taken. To this was added 2 cc. of 5 per cent potassium iodide and 2 cc. of dilute hydrochloric acid and the liberated iodine was titrated with 0.1 N sodium thiosulfate solution. The peroxide analyzed 90 per cent pure. 

Renzoylhyd roperoxide has always been prepared by the action of sodium ethylate on benzoylperoxide and subsequent acidification with dilute sulfuric acid.2... 

A mixture of 2,2-(5-methyl-l,3-phenylene)di(2-methylpropionitrile) (2.26 g), N-bromosuccinimide (1.78 g), benzoylperoxide (0.05 g) and carbon tetrachloride (50 ml) was refluxed for 2 hours, cooled and filtered, and the filtrate was evaporated to dryness under reduced pressure. The residue was dissolved in dimethylformamide (20 ml), sodium triazole (1.8 g) was added, and the mixture was stirred at room temperature for 18 h. Water (100 ml) was added, and the mixture was extracted twice with ethyl acetate, dried and evaporated to dryness and the residue was purified by flash column chromatography, eluting with ethyl acetate to give 2,2-[5-(lH-l,2,4-triazol-l-ylmethyl)-l,3-phenylene]di(2-methylpropionitrile), mp 81-82°C after crystallization from ethyl acetate/cyclohexane. 

The graft copolymer portion can be as low as 20% of the total system. Surfactants such as Aerosol MA-80, Aerosol OT, Emcol 4600 (sodium Tridecyl Sulfosuccinate), Surfynol 104, Igepal CO-630 (Nonylphenol polyethylene oxide) etc. can be added at the beginning of the polymerization without causing significant difference in the polymerization. Other initiators such as persulfate, benzoylperoxide etc. can also be used. 

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