Separation of racemic from meso-2,3-butanediol
2,3-Butanediol containing less than 3% of the meso form has been obtained from samples containing up to 50% of the meso form. The diacetate was obtained by esterification with acetic anhydride in the presence of traces of sulfuric acid as a catalyst and was then purified. When the diacetate was held at 4 degrees C, crystals of racemic 2,3-butanediol diacetate formed, and these were separated by filtration. The diacetate was then transformed back to 2, 3-butanediol by transesterification with methanol in the presence of sodium methylate as a catalyst. The resulting 2,3-butanediol contained less than 3% of the meso form. For an original batch of 2, 3-butanediol containing 50% dl and 50% meso, this method can isolate up to 70% of the racemate content. If the original 2,3-butanediol contains too much meso form, racemic 2,3-butanediol diacetate does not crystallize, but 2,3-butanediol containing up to 60% of the meso form can be enriched up to 70% racemate by distillation. Copyright 1999 Academic Press.
Utille
JP
Centre de Recherches sur les Macromolecules Vegetales (affiliated with Universite Joseph Fourier de Grenoble), CNRS, Grenoble Cedex 9, 38041, France.
Boutron
P