Reactive extraction of 2,3-butanediol from fermentation broth

Biochemical 2,3-butanediol is a renewable material, but the lack of an effective separation process limits its industrial application. We developed an effective separation process to recover 2,3-butanediol from fermentation broth by reactive-extraction with ion-exchange resin HZ732 as catalyst. n-Butylaldehyde was used as both reactant and extractant. Feasible operation conditions were obtained as follows: room temperature, Ccat=200 g·L−1, three-stage cross-current extraction, with reactant ratio (VButylaldehyde: Vfermentation broth) 0.05 for each stage. Reactive-extraction can recover over 98% of 2,3-butanediol in the form of 2-propyl-4,5-dimethyl-1,3-dioxolane from fermentation broth. Then 2,3-butanediol was obtained by hydrolyzing 2-propyl-4,5-dimethyl-1,3-dioxolane and purified by vacuum distillation. The total yield rate of 2,3-butanediol through the process was over 94% and purity of final product reached 99%.