1. 75 L of water was added to the reactor followed by (S)-epichlorohydrin (99.3% ee). Under stirring conditions, 4.76 kg of 25% aqueous sodium cyanide and 3.30 kg of 50% aqueous citric acid were slowly added dropwise for 1 h. 2. The pH was maintained between 7.9 and 8 during the reaction, and the temperature was controlled at 22-25°C for 50 min. 3. After completion of the reaction, stirring was continued for 10 h. Then 0.7 kg of sodium chloride was added and stirred until it was The reaction mixture was extracted with 20 L of ethyl acetate and the organic layer was separated. 5. 0.2 kg of anhydrous sodium sulfate was added to the ethyl acetate layer, stirred for 30 min and filtered. 6. The ethyl acetate was removed by evaporation under reduced pressure, and the residue was distilled through a membrane distiller at 110°C/1 mbar to give 1.77 kg of (S)-4-chloro-3-hydroxybutanenitrile (Yield 91.3%, chemical purity 99.1%). 7. and 99.1% chemical purity).7. The optical purity of the product was determined to be 99.3% ee by GC analysis.8. The experiments were repeated under different reaction conditions according to the same method and the results are summarized in Table 1.
