Production method of phenacetin

(1) Obtained by acetylation of p-aminophenethyl ether. The mixture of benzene, acetic anhydride and p-aminophenethyl ether is heated azeotropically on an oil bath for 4 hours. After the reaction is completed, the reactant is cooled, that is, phenatin is precipitated, which is filtered, washed with cold benzene, and dried. The yield is the theoretical amount. 86% of it.

(2) Derived from the action of acetaminophen and sodium ethoxide: first add p-acetamidophenol to sodium ethoxide, then slowly add ethyl iodide, heat to reflux for 1h, cool and filter, and the resulting crude product is dissolved in ethanol. After filtering, the filtrate is diluted with hot water, then cooled, filtered, and dried to obtain a finished product. The output is 80% of the theoretical amount. The first method can also use acetic acid instead of benzene as a solvent. The process is as follows. Heat 40% dilute acetic acid to boiling, put in p-aminophenethyl ether, distill off the water, add glacial acetic acid when the temperature rises to 150°C, reflux for 1h, continue to steam, wait until the temperature rises above 150°C, take a sample and determine free aminobenzene Diethyl ether, add acetic anhydride according to the amount of residual amino phenyl ethyl ether, reflux reaction for 0.5h, check the end point, depressurize after passing, and recover acetic acid until the amino content is below 0.046 and the acid content is below 0.2%, and the reaction is hydraulically pressed into the hot refined mother liquor. Stir and cool to 40℃, filter to obtain crude phenacetin. Refining, add boiling water or refined mother liquor to the crude phenacetin, heat and stir to dissolve, filter, adjust the filtrate with acid to pH=4.5-4.7, add activated carbon and sodium thiosulfate and stir to decolorize, filter, cool the filtrate to crystallize, shake and filter, airflow Dry, get phenacetin.