Abstract: The high concentration of alkaline waste liquid is generated from chitin when it is used for preparing chitosan. In traditional production the alkaline waste liquid is discharged，causing waste and pollution. The alkaline waste liquid can be used for the production of a preservative，sodium diacetate（SDA）.This papre studied discoloring and enriching the liquid，addition of acetic acid，reaction temperature，reaction time，drying temperature and drying time. The optimum preparation conditions were determined. Percentage contents of acetic acid，sodium acetate and water in the product were 40.38，58.42 and＜2 respectively by using the technology. They met the quality specification of FAO/WHO.

摘要： 工业上用甲壳素生产壳聚糖会产生高浓度强碱性废液，传统工业方法是将其处理后排放，这样既浪费资源又污染环境。本文利用该废液制备防腐剂——双乙酸钠（SDA），从废液脱色、浓缩、投入乙酸的量、反应温度、反应时间、干燥温度与时间等制备条件进行了研究，确定了最佳制备工艺。所得产品中含40.38%乙酸和58.42%乙酸钠，水含量小于2%，质量符合FAO/WHO标准。