Ultrafast Continuous-Flow Synthesis of Crystalline Microporous Aluminophosphate AlPO₄-5

Crystalline microporous materials have been typically synthesized by long-time hydrothermal treatment in a batch reactor, which suffers from drawbacks like frequent start-up and shut-down operations and low energy efficiency. The development of a continuous flow process for the synthesis of crystalline microporous materials is extremely challenging due to the slow crystallization of the microporous materials. In this work, we demonstrate the continuous flow synthesis of an important crystalline microporous aluminophosphate material, AlPO 4 -5. The continuous synthesis of AlPO 4 -5 was achieved by combining the seed-assisted method with a continuous flow reactor that could provide a much higher heating rate. The results showed that single phase AlPO 4 -5 was obtained after one-minute synthesis in the continuous flow reactor. A stable continuous process was maintained, because any hydrodynamic failure from the precipitation of the solid product could be minimized thanks to the ultrafast synthesis and the small particle size of the AlPO 4 -5 product. In addition, the reuse of the product from the continuous flow synthesis as a seed is demonstrated. This easily designed, efficient route can result in the significant cost and energy savings and thus has huge potential for the industrial-level production of AlPO 4 -5 crystals in the future.