Sulfuric Acid → 3-Chloro-4-methylphenol

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Reaction Steps

238 g of 3-chloro-4-methylaniline, 1000 ml of water and 500 ml of concentrated sulfuric acid were mixed, initially at room temperature. The temperature of the mixture rose to 95° C. The mixture was stirred at room temperature for 30 minutes, cooled to 5° C. and a solution of 145 g of sodium nitrite in 500 ml of water was slowly added (1.5 hours) to the stirred mixture at 5°-10° C., then the mixture was stirred at about 5° C. for one hour. The resulting solution was added over two hours to a stirred solution of 1.2 liters of concentrated sulfuric acid in 2 liters of water, at 105°-110° C., and the resulting mixture was stirred at 110° C. for one hour, then held at room temperature for 18 hours. Then 3.5 liters of hexane was added, the mixture was stirred for 30 minutes, allowed to stand, and the two liquid phases were separated. The hexane phase was filtered, washed with water, dried (MgSO4) and concentrated to dryness to give crude (91%) 3-chloro-4-methylphenol (4A).

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