Obtained by acetylation of paraminophen.

Method 1: Add  Paracetamol  to dilute acetic acid, then add glacial acetic acid, temperature rise to 150ºC for 7h,  reaction for 2h, check the end point, qualified, cool to below 25ºC, filter, wash until no acetic acid taste, shake dry, coarse product.

  Method 2: Paracetamol , glacial acetic acid and acid mother liquor containing more than 50% acid were distilled together, and the rate of evaporation of dilute acid was 1/10 of the total amount of distillate per hour First, when the internal temperature rises to more than 130ºC, sample to check the residual amount of Paracetamol  is less than 2.5%, add dilute acid (content of more than 50%), cooling crystallization. Filter, first with a small amount of dilute acid washing, and then with a lot of water to filtrate close to colorless, coarse product. The yield of method 1 is 90%. The yield of method 2 is 90-95%. Refining method: When the water is heated to the near boiling point, the crude product is put into it. Add activated carbon soaked in water, adjust with dilute acetic acid to pH=4.2-4.6, and boil for 10min. Press and filter the filtrate with a small amount .Cooling to below 20ºC, crystallization. The product was filtered, washed and dried to produce paracetamol. Other production methods are: (1) Reduction with zinc in glacial acetic acid and acetylation to obtain p-acetaminophen; (2) The hydrazone generated by p-hydroxyacetophenone is placed in sulfuric acid solution,  and translocation is generated to acetaminophen.