Purification of hydrobenzoin enantiomers by stripping crystallization

Stripping crystallization (SC) is introduced in this work for the purification of hydrobenzoin enantiomers. In principle, SC is operated at a series of the three-phase equilibrium conditions, in which the liquid mixture is simultaneously vaporized and crystallized. Thus, SC combines distillation and crystallization to produce pure crystals. A thermodynamic model is developed to simulate the three-phase equilibrium during the SC operation and to direct the batch SC experiments. The experiments show that SC can be applied to purify (R,R)-hydrobenzoin from the chiral hydrobenzoin mixture. The experimental purity of the final product obtained by SC is consistent with the simulated purity predicted by the model although the experimental recovery ratio is lower than the simulated recovery ratio.