i68 PRACTICAL ORGANIC CHEMISTRY Yield of crude product, 14 g., the high value being due to traces of polynitro-derivatives. Recrystallise the crude pale yellow product from methylated spirit, filter at the pump, wash quickly with a few ml. of fresh spirit, and then drain and dry. The yeJlow o-nitroacetanilide remains in the filtrate, whilst the p-nitroacetanilide is obtained as colourless crystals, m.p. 214°. A second recrystallisation of the para compound should not be necessary. Yield of pure product, 8 g. Hydrolysis to p-Nitroaniline. For this purpose use 70% sulphuric acid, the usual reagent employed for the hydrolysis of anilides (p. 108). Add 5 g. of the recrystallised p-nitro-acetanilide to 30 ml. of 70% sulphuric acid, and boil the mixture gently under a reflux water-condenser for 20 minutes. Then pour the clear hot solution into about 150 ml. of cold water, and finally add an excess of sodium hydroxide solution until precipi-tation of the yellow p-nitroaniline is complete. Cool the mixture
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