The method for producing optically active racemic menthol

The present invention is particularly economical comprehensive process for preparing menthol, specifically, a substantially pure L- menthol and racemic menthol as enantiomers and diastereoisomers of the optically active, industrial scale in regarding the method for manufacturing starting from citral cheaply available starting materials. The method comprising, a. Obtaining a citronellal 1) neral and / or geranial a by catalytic hydrogenation, b. 1) a step of cyclizing the isopulegol citronellal in the presence of an acidic catalyst, c. 1) a step of purifying by crystallization isopulegol, d. 1) isopulegol and by catalytic hydrogenation so as to obtain a menthol.