Nitric Acid → 5-Nitronaphthalene-1,4-dione

Beteiligte Stoffe

Reaktionsbedingungen

Reaktionsschritte

In the same apparatus as in Example 1, 20 g of 1,4-naphthoquinone was added, with stirring, to 70 g of a mixed acid consisting of 66 percent by weight of sulfuric acid, 19 percent by weight of nitric acid and 15 percent by weight of sulfur trioxide while maintaining the mixed acid at 0° to 5°C. The temperature of the mixture was gradually raised to 15°C over 30 minutes and maintained at 15°C for 3 hours to complete reaction. The reaction mixture was then stirred into 400 ml of water at 20°C in 5 minutes to precipitate crystals, while cooling the water as to maintain a liquid temperature at 40°C. The state of dispersion of the precipitated crystals was good. The precipitate was processed in the same manner as in Example 5 to obtain 22.7 g of crude 5-nitro-1,4-naphthoquinone of a melting point of 155°C. The crystals were of a nearly equal particle size not exceeding 0.2 mm. The amount of acidic matter remaining in the crystals was 0.4 percent by weight in sulfuric acid equivalent.

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