Abstract: In classical organic synthesis laboratory teaching experiment, students usually cannot achieve an expected yield and the variation of yield is often big. Students can usually understand the experimental principles, experimental procedures and experimental precautions, but there is a lack of in-depth discussion on how to improve the yield and purity of synthetic products. We propose an efficient “reverse-step optimization method”. The ethyl acetate synthesis experiment is first divided into three experimental stages, including reaction distillation, washing and drying, and product distillation. Then, the main influencing factors of each stage are optimized in a reverse manner by using internal standard chromatography to analyze the purity and yield of the product. After improvement, the product purity and yield remain stable with the former between 96% and 99%, and the latter between 72% and 75%. Integrating the “reverse-step optimization method” into the classic experiment helps to consolidate the foundation, strengthen students’ mastery of basic operation skills and understanding of theoretical knowledge, and also helps to cultivate students’ scientific research thinking, thereby revitalizing the classic experiment.

Key words: Reverse-step optimization method, Classical organic experiment, Student training