Efficient crystallization process of dodecanedioic acid by a pneumatically agitated crystallizer

Abstract

Dodecanedioic acid (DC12) is mainly prepared via microbial synthesis in industrial production, however, the refined products have many drawbacks, such as low purity, poor crystal size distribution (CSD), and heavily agglomerated character, to name a few. Therefore, the refining process is a crucial step in DC12 preparation by microbial production. In this study, a novel pneumatically agitated crystallizer for DC12 refinery by gassing crystallization was developed. A batch cooling crystallization process was developed, providing the final crystal in 82.0% yield and purity increment to 99.20% at the end of crystallization process. Optimized conditions were determined as the initial supersaturation ratio of 300:3000 (g/mL) and gassing air flow rate of 4 L/min with solution preparation temperature of 85 °C. The crystal products with significantly better morphology characteristics than the starting crude feedstocks, including crystal uniformity and color brightness, were harvested. These obtained results indicated that the pneumatically agitated crystallizer-based crystallization process without any mechanical agitation was a robust and economically feasible technique. To our knowledge, this is also the first DC12 crystallization process with sole gassing agitation for unseeded batch cooling crystallization.