The first attempt at continuous-mode separation of racemic and meso-2,3-butanediol with high purities using a simulated-moving-bed process

To maximize the industrial value of biologically produced 2,3-butanediol (BD), it is essential to separate BD into its stereoisomeric fractions, meso-BD and racemic-BD. To address such issue, a highly efficient BD-isomer separation process based on a simulated-moving-bed (SMB) mode was developed in this study. As a first step for this task, the competitive adsorption behaviors of meso-BD and racemic-BD on a properly selected adsorbent were investigated, and their relevant isotherm parameters were determined using inverse method. The determined isotherm parameters were then applied to the design of the BD-isomer separation process based on an SMB mode, which was carried out in such a way that both BD isomers could be separated with high purities and little losses in a continuous countercurrent mode. The performance of the designed SMB process for the targeted separation was experimentally investigated. It was confirmed from the experimental results that the BD-isomer separation SMB process, which was developed in this study for the first time, could be effective in the continuous-mode separation of meso-BD and racemic-BD with the purities higher than 99.9% and 97% respectively while maintaining their losses below 1%. The results of this study are expected to pave the way for establishing a highly economical process for a large-scale production of meso-BD and racemic-BD with high purities.