AbstractThe mixture ofdl‐menthyl chloroacetaee isomers and the mixture ofdl‐menthyl cyanoacetate isomers were prepared by the esterification of the mixture ofdl‐menthol with chloroacetic acid and cyanoacetic acid, respectively. In these mixtures thedl‐menthyl chloroacetate m. p. 23–24° and thedl‐menthyl cyanoacetate m. p. 63–63.5° are crystal form, the other isomers, such asdl‐isomenthyl cyanoacetate b.p. 136–138°/3mmHgare liquid form. The crystal form ester waa isolatded from liquid form ester by cooling crystallization, and thendl‐menthol m. p. 32–33° was obtained by hydrolysis. The isolation effect has intimately relation to thedl‐menthol content in raw material, the moredl‐menthol content, the more yield and purity of crystal form ester, therefore, after hydrolysis, the obtaineddl‐