Salting-out of 1,3-propanediol from aqueous solutions by inorganic electrolytes

BACKGROUND: The cost of 1,3-propanediol (1,3-PD) microbial production depends very much on the separation of 1,3-PD from the fermentation broth. This work develops a salting-out process separating 1,3-PD from aqueous solutions. The salting-out effects of K2CO3, K3PO4, and K4P2O7 on the liquid-liquid phase equilibria for different aqueous solutions of 1,3-PD were investigated at 298.15 K. RESULTS: The distribution coefficient and selectivity coefficient of 1,3-PD increased significantly with increase of the initial salt concentration in the salting-out systems. Increasing the initial 1,3-PD concentration in the aqueous solution improved the distribution coefficient and selectivity coefficient of 1,3-PD, resulting in higher recovery of 1,3-PD. CONCLUSION: The solubility of 1,3-PD in the aqueous phase was mainly determined by the salt species and its concentration. The initial 1,3-PD concentration in the aqueous solution had a negligible effect on the solubility of 1,3-PD in the aqueous phase, which showed a linear relation with the molality of salt in the aqueous phase. Moreover, the solubility of 1,3-PD in the organic phase or the aqueous phase could be predicted by the initial salt concentration. (C) 2016 Society of Chemical Industry