Novel process for biochemical optical resolution of 2DL-racemic compound of .alpha.-tocopherol ester or substances which contain the same, using culture broth, whole cell, or culture filtrate, which are obtained by cultivating microorganisms which possess an ability for hydrolysis of said ester. Beneficial advantage of the process resides in its low cost, simplicity and high resolution ratio.

1-Menthol can be readily obtained from racemic menthol by conversion of the latter to the diastereomeric esters of an optically active amino acid and chromatographing the diastereomers. The separation of the diastereomeric esters is relatively insensitive to the support or to the solvent used as eluant, and satisfactory separation occurs under a broad variety of conditions. 1-Menthol can be obtained by base catalyzed hydrolysis of the purified diastereomer with high optical purity.

This invention relates to odor neutralizers comprising esters of the formula (I) wherein R.sup.1 is an alkyl radical with 1 to 4 carbon atoms which can optionally contain a double bond; R.sup.2 is a hydrogen or an alkyl radical with 1 to 3 carbon atoms which can optionally contain a double bond; R.sup.3 is a hydrogen or a methyl radical substituted by the alkyl radicals R.sup.9 and R.sup.10; R.sup.4 is a hydrogen, a methyl radical or an acyloxy radical of the general formula O--CO--R.sup.1 wherein R.sup.1 has the abovementioned meaning; R.sup.5, R.sup.6, R.sup.7, R.sup.8 and R.sup.10 are identical or different and is hydrogen or methyl; R.sup.9 is a hydrogen and R.sup.4 and R.sup.9 can together represent a single carbon bond or a methylene or an ethylene bridge,with the proviso that i) in the case of cyclohexyl esters in which R.sup.1=methyl, R.sup.2=isopropyl, R.sup.5=methyl and R.sup.6=hydrogen, the substituents R.sup.2 and R.sup.5 are arranged in a cis relationship to each other; ii) in the case of cyclohexyl esters in which R.sup.2=isopropenyl, R.sup.5=methyl and R.sup.6=hydrogen, the substituent R.sup.1 is an alkyl group with at least two C atoms; iii) in the case of acyclic monofunctional esters, the substituent R.sup.1 is an alkyl group with at least two C atoms; and iv) in the case of cyclohexyl esters in which R.sup.2, R.sup.7, R.sup.8=hydrogen and R.sup.5, R.sup.6, R.sup.10=methyl, the substituent R.sup.1 is methyl, ethyl, propyl or 1-propen-1-yl.