87-91-2

64-17-5

87-69-4

87-91-2

(1) 30 g of L-(+)-tartaric acid was added to a 500 mL three-necked flask followed by 150 mL of anhydrous ethanol. The stirrer was turned on to make the mixture homogeneously mixed, and the reaction temperature was controlled in the range of 0 to 30 °C. 95.4 g of thionyl chloride was slowly added dropwise for 1.5 h, taking care to control the rate of dropwise acceleration to manage the exothermic process. After the dropwise addition, the reaction system was warmed up to 50 °C and the reaction was continued for 2 hours. After completion of the reaction, ethanol was removed by distillation under reduced pressure to obtain the crude product of diethyl L-(+)-tartarate. (2) To the above crude product, 3.3 g of potassium bicarbonate was added, the temperature was raised to 20 °C and the reaction was stirred for 3 hours. At the end of the reaction, the solid insoluble matter was removed by filtration to obtain 39.6 g of L-(+)-diethyl L-tartrate, and the product was a colorless or light yellow oily liquid with a molar yield of 96.2%. The purity of the product was tested to be 99.4%.