A Promising Solution to Ensure Ibuprofen Continuous Crystallization Limiting the Encrustation in a Couette-Taylor Crystallizer

The continuous Pasteurian chiral resolution of (±)-ibuprofen by using diastereomers with S-α-methylbenzylamine appears to be prone to encrustation. This comes from the necessity of operating under high supersaturation in order to obtain an acceptable yield. A kind of dead zone growth appears when the two diastereomeric salts coexist. Several remedies have been contemplated. The best solution led to design a setup of four CT crystallizers in parallel. Each reactor would be periodically disconnected from the system to undergo a preventive antifouling cleaning procedure, including temperature cycling and pure solvent circulation. A recycling stream could be implemented to recover the cleaning liquors. Finally, to better control the crystallization process, each CT crystallizer would have the possibility of performing an axial and radial temperature gradient.