5-Amino-o-cresol

95-74-9

2835-95-2

General procedure for the synthesis of 2-methyl-5-aminophenol from 3-chloro-4-methylaniline: 1700 kg of 50% sodium hydroxide solution was added to a 4800 L autoclave, followed by 1850 kg of ethanol solution containing 1000 kg of 3-chloro-4-methylaniline. Then 50kg of cuprous chloride and 15kg of copper powder were added as catalyst. The reaction vessel was sealed and replaced with nitrogen five times to ensure an oxygen-free environment. The reaction mixture was heated to 175°C and maintained at this temperature for 4 hours, during which time it was sampled and analyzed to monitor the progress of the reaction. Upon completion of the reaction, the mixture was cooled to room temperature. Ethanol was recovered under reduced pressure and then the reaction mixture was filtered and transferred to an 8000 L tank. The pH was adjusted to weak acidity by adding 1450 kg of industrial hydrochloric acid to the filtrate. Extraction was carried out with 2000L of ethyl acetate for three times. The organic phases were combined and the ethyl acetate was recovered by distillation under reduced pressure to obtain the crude product. To the crude product, 1000kg of ethanol was added, heated to 60°C to dissolve, and then 50kg of activated carbon was added to decolorize. After stirring for 1 hour, the activated carbon was removed by hot filtration and the filtrate was cooled to 5°C for crystallization. Finally, 707kg of 2-methyl-5-aminophenol was obtained with a yield of 85.36% and a purity of 99.8%.