Separation of racemic from meso-2,3-butanediol

2,3-Butanediol containing less than 3% of the meso form has been obtained f rom samples containing up to 50%, of the meso form. The diacetate was obtai ned by esterification with acetic anhydride in the presence of traces of su lfuric acid as a catalyst and was then purified. When the diacetate was hel d 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 containi ng 50% dl and 50% meso, this method can isolate up to 70% of the racemate c ontent. If the original 2,3-butanediol contains too much mese form, racemic 2,3-butanediol diacetate does not crystallize, but 2,3-butanediol containi ng up to 60% of the mese form can be enriched up to 70% racemate by distill ation. (C) 1999 Academic Press.