PREPARATION OF FLOTATION OF OPTICALLY ACTIVE ALIPHATIC CARBOXYLIC ACIDS

摘要

2128518 9315037 PCTABS00024 An improved process for the separation of enantiomers of a mixture of certain aliphatic carboxylic acids or esters thereof is disclosed. The process involves adding in inert liquid to the reaction solution formed by: (i) forming a salt solution comprising said racemic mixture of a C1 to C6 linear or branched aliphatic carboxylic acid and an organic or inorganic base; (ii) treating said salt solution with less than equimolar equivalents of a chiral organic nitrogenous base; (iii) precipitating from the reaction solution formed in step (ii) the less soluble diastereomeric salt; (iv) addition of a countersolvent to the slurry formed in step (iii); (v) extracting the more soluble diastereomeric salt or the salt of carboxylic acid and the base added in step (i) into the countersolvent. The inert liquid and the countersolvent must be of sufficiently different density. The inert liquid is substantially immiscible with the countersolvent and does not dissolve appreciable quantities of the precipitated less soluble diastereomeric salt.