Ethanol (1 L) was added to a three-necked flask and cooled to 0°C under stirring conditions. Concentrated hydrochloric acid (80 mL) was added slowly dropwise, followed by the slow addition of thionyl chloride (132 mL). The reaction system was allowed to gradually warm to room temperature. 3-Hydroxypropionitrile (250 g) was added slowly and dropwise at room temperature and then the reaction mixture was refluxed for 6 hours. A large amount of white precipitate was observed to be generated during the reaction. After completion of the reaction, the system was cooled to 0 °C and the pH was adjusted to neutral (about 7) with solid sodium carbonate. The solid impurities were removed by filtration, the filtrate was concentrated and finally purified by distillation to give 208 g of ethyl 3-hydroxypropionate in 50% yield.
