Chemistry Letters, Vol.30, No.4, 364-365, 2001
Influence of the process on the mechanisms and the performances of the preferential crystallization: Example with (+/-)-5-(4-bromophenyl)-5-methylhydantoin
Resolution of the title compound is carried out at a two liter scale via two different processes of preferential crystallization (PC), the Auto Seeded Programmed Polythermic Preferential Crystallization (AS3PC) process and the classical Seeded Isothermal Preferential Crystallization (SIPC) process. The ratio, crystal growth rate/secondary nucleation rate, is strongly under the influence of the process. Consequently AS3PC process appears more efficient than SIPC process in terms of purity of the crops (optical purity), yield, easiness of scale up and downstream operations such as filterability.