Organic Syntheses, CV 3, 649
Submitted by Charles C. Price and Edwin Krebs.
Checked by R. L. Shriner and C. H. Tilford.
1. Procedure
A
600-ml. beaker containing 100 ml. of water and equipped with an
efficient stirrer, a
thermometer, and a
200-ml. separatory funnel is immersed in an
ice-water bath. When the temperature of the water has fallen to 0–5°,
10 g. (0.13 mole) of sodium peroxide (Note
1) is added. Then, with vigorous stirring, a solution of
37 g. (0.2 mole) of p-nitrobenzoyl chloride in
100 ml. of dry toluene is added dropwise over a period of about 30 minutes. After the mixture has been stirred for an additional 1.5 hours, the precipitate is filtered and washed with 200 ml. of cold water (Note
2). The yield of
p-nitrobenzoyl peroxide is
28.5–29 g. (
86–88%). It melts at
155–156°.
The product may be recrystallized most conveniently by dissolving it as rapidly as possible (Note
3) in
500 ml. of dry toluene which has been preheated to 80–85°. As soon as the solid is completely dissolved (2–3 minutes of stirring), the solution is filtered through a warm
Büchner funnel and the filtrate is immediately cooled in an
ice-water bath. The yield of very pale yellow glistening needles is
25 to 26 g. (
86–89% recovery); they melt at 156° with vigorous decomposition (Note
4).
2. Notes
1. In a parallel experiment in which
25 g. of sodium peroxide was used, the precipitate was not the peroxide but evidently consisted of
sodium p-nitroperbenzoate.
3. Excessive heating during recrystallization leads to extensive decomposition of the peroxide.
3. Discussion
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