Sulfuric Acid → 2,5-Dibromophenol

Beteiligte Stoffe

Reaktionsschritte

61.6 Grams of 2,5-dibromoaniline and 250 g of 75% aqueous sulfuric acid solution were charged into a ceramic ball mill having one liter capacity. A suspension of fine particles of 2,5-dibromoaniline sulfate was prepared by a method similar to that described in Example 5. The suspension was transferred into a beaker having one liter capacity. The ceramic ball mill used was washed with 120 g of 75% aqueous sulfuric acid solution and the washings were transferred into the beaker. Diazotization of 2,5-dibromoaniline sulfate in the form of suspension of fine particles was carried out by a method similar to that described in Example 5 except that 18.2 g of sodium nitrite powder was added. Hydrolysis of 2,5-dibromobenzenediazonium sulfate was carried out by a method similar to that described in Example 5. A xylene layer was isolated from the hydrolyzed product and a crude product of 2,5-dibromophenol was obtained after the xylene was removed by distillation. The crude product of 2,5-dibromophenol was steam distilled by introducing superheated steam. After the distillate was cooled, crystallized 2,5-dibromophenol thus formed was obtained by filtration and dried. 47.3 Grams of 2,5-dibromophenol having melting point of 71°-74° C was obtained. The yield was found to be 85.0%.

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