Acetic Anhydride → O-acetyl-5-chlorosalicylic acid

Participants

Reaction Steps

10 g (57.9 mmol) 5-chlorosalicylic acid was weighed in a 100-mL round-bottomed flask, followed by the addition of acetic anhydride (12.8 mL, 115.9 mmol). The mixture was stirred for 5 minutes before adding concentrated sulfuric acid (2 drops). The reaction was refluxed for 3 hours. Progress of the reaction was monitored by HPLC. The reaction mixture was cooled to room temperature and poured into a beaker containing 2N HCl (200 mL) to precipitate the product out. The product was collected via vacuum filtration. A purity check by HPLC revealed the presence of impurities. The precipitate was stirred in water (150 mL) overnight in a 200-mL round-bottomed flask. The insoluble solid was collected via vacuum filtration. An impurity check by HPLC revealed that the crude product was free of the impurities. The product was dried overnight in vacuo to yield 12 g of O-acetyl-5-chlorosalicylic acid (56 mmol, 97% yield)

Provenance & Evidence