(235c) Novel Chiral Separation Via Integration of Membrane Separation with Cooling Crystallization: Dl-Glutamic Acid Resolution

Chiral separation of racemic mixtures is essential in the production of many pharmaceutical compounds, and the objective of here is to establish an alternative for existing chiral separation processes. Resolution of DL-glutamic acid is used as model system in testing the integration of membrane separation with cooling crystallization. The proposed process utilizes two crystallization chambers that are separated by a membrane that prevents transport of crystals from one chamber to the other. It is critical that system conditions are controlled so that only one isomer crystallizes in each of the chambers. This is done by appropriate addition of seed crystals to each chamber and by restricting the formation of new crystals to secondary nucleation mechanisms. The seed crystals introduced to each of the chambers may grow or participate in secondary nucleation, but conditions must be controlled so as to prevent primary nucleation, which would result in the formation of both crystal species in each chamber. Experiments with different amount of seed crystals were conducted to determine operating conditions that produce the highest product yield and purity. Results were promising as the product purity was over 94% (separation factor of 16) and the product yield was increased by at least 30% of the cooling crystallization process without the membrane.