Study on purification technology of crude acetaminophen
Zhang Shaomeng1， Zhao Jianwei2， Zhang Dong3
1. Hebei Provincial Drug Evaluation Center， Shijiazhuang 050033， China; 2. Hebei Jiheng Group Corporation Ltd., Hengshui 053000, China； 3. Hebei Pharmaceutical and Medical Device Inspection and Research Institute， Shijiazhuang 050033， China
Abstract： The traditional method of refining or purifying the crude acetaminophen is to use water as solvent to recrystallize the crude product, and the purity of the product is low. In order to obtain the finished product with higher purity, the structural formula of the unknown impurity dimer was determined by experiments. By analyzing the physical and chemical properties of its structural formula, it was judged that the unknown impurity was easily soluble in alcohol reagents. Ethanol was selected as the solvent according to the production experience, and through the investigation of the amount of activated carbon, decolorization temperature and time, the optimum production process conditions were determined: the amount of ethanol solvent added is 4 030 kg, the decolorization temperature is 81 ~ 84 ℃, the amount of activated carbon added is 60 ~ 90 kg, and the decolorization time is 30 min. The products can meet the requirements of European Pharmacopoeia EP9.
