Continuous Production of an API Suspension (ZS-9) under Oscillatory Flow at Intensified Temperature and Pressure

A baffleless oscillatory flow coil reactor is implemented for the continuous production of a sodium zirconium cyclosilicate (SZC) species (ZS-9) suspension at elevated temperature and pressure. Development of the process and the resulting effects on product quality are outlined, including both mechanical changes to the reaction system itself and parametric tests of the operating conditions. The reaction apparatus proceeded through several iterations, where physical changes upstream of the crystallization coil from a simple T-junction mixing point to the final system containing a prefilled seeding loop led to significant improvements in product quality. The effects of system temperatures, fluid space times, and oscillation intensity are then outlined, leading to final operating conditions consisting of a 1 h crystallization fluid space time at 245 °C and up to 75 bar, a 173 °C seeding temperature, and a velocity ratio (Reo/Ren) ratio of 175 and a ZS-9 production rate of 40 g/h.