Synthesis
To the 500ml reaction flask add 2-amino-4-nitrophenol 30.8g (0.2mol), 150g of ethylene dichloride, and 0.5g of iodine-containing ferric chloride, stirring, lower the temperature to 15 ??, began to drop 29.7g (0.22mol) sulfuryl chloride, the reaction is slightly exothermic, control the droplet temperature below 20 ??, droplet after the end of the heat preservation of 1.0 hours, and then slowly increase the temperature to 35 ??, hold 2 hours, sampling control to raw materials less than 0.5%, the end of the reaction, distillation under pressure to recover dichloroethane, the first recovery of 70% of the solvent (by volume), and then make up 200g of deionized water, and continue to steam the solvent, to be fully recovered dichloroethane, drop 30% of the liquid alkali to the reaction solution pH to 8.5, the temperature rose to 80 ??, the material is completely soluble, add 3g of activated carbon, hold 1.0 hours. After the material is completely dissolved, add 3g of activated carbon, keep warm for 1.0 hours, filter while hot, the filtrate is cooled down to 30??, start to add hydrochloric acid dropwise, adjust the pH to 4.5, keep warm for 0.5h, filter, get 50g of yellowish-green color tide, dry at 70?? for 18 hours, get reddish-brown solid 2-amino-6-chloro-4-nitrophenol 30.2g, the yield is 80.0%, HPLC: 99.5%.
