Abstract: Synthesis of ethyl lactate with rectification was designed and optimized by central composite rotable design (CCRD). And predicted values on the contour plots were tested. Results showed that the ethanol/lactic acid ratio was the significant factor for esterification yield, and the interactions between ethanol/lactic acid ratio and cyclohexane/lactic acid ratio, ethanol/lactic acid ratio and heating temperature were less significant. The correlation coefficient of predict values and experiment values was 0.988.The optimum conditions in the experiment rang: ethanol/lactic acid ratio 4:1, cyclohexane/lactic acid ratio 0.8:1, catalyst loading 2%, incubation period 3 h and heating temperature 110 ℃. The esterification yield is 94% under these conditions.

Key words: lactic acid, esterification, technology, central composite rotable design