1-Chloro-2,4-Dinitrobenzene → 2,4-Dinitrophenol

Beteiligte Stoffe

Reaktionsschritte

A mixture of 183 parts of 2,4-dinitrochlorobenzene, 16 parts of 2,4-dinitrophenol and 3 parts of 2,4-dinitromethoxyethoxybenzene is saponified to 2,4-dinitrophenol in a mixture of 303 parts of 33% strength sodium hydroxide solution and 3,000 parts of water at 95° C. under an atmosphere of air. The resulting suspension i adjusted to a pH value of 3.5 by adding 185 parts of 31% strength hydrochloric acid. After 10 parts of the sodium salt of a naphthalenesulfonic acid formaldehyde condensation product (dispersing agent), 1 part of iron(III) chloride and 1 part of iodine trichloride have been added, 650 parts of 13 percent strength by weight chlorine bleach liquor (containing 150 g of active chlorine per liter) are added dropwise at 10° C. in the course of 8 hours, the pH increasing meanwhile. In the course of the addition, the pH reaches a value of 4.5. After it has reached this value, the pH is caused to remain, during the chlorination, within the range 4-4.5 by the simultaneous addition of 36 parts of 31% strength hydrochloric acid during the dropwise addition of the remainder of the chlorine bleach liquor. The pH of the suspension is then adjusted to a value of 1.0 by means of 170 parts of 31% strength hydrochloric acid, and small amounts of sodium hypochlorite still present are destroyed by means of 15 parts of 40% strength sodium bisulfite solution. The resulting product is then isolated by being filtered off at about 10° C. 200 parts of pale yellow 6-chloro-2,4-dinitrophenol (melting point: 101°-109° C.), now only containing traces (0.5%) of 2,4-dinitrophenol, are obtained.

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