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Seed-Assisted Effects on Solution-Mediated Phase Transformation: A Case Study of l-Histidine in Antisolvent Crystallization

Liu, Ya, Xu, Shijie, Liu, Yumin, Chen, Mingyang, Chen, Yifu, Du, Shichao, Wang, Yaping, Sun, Panpan, Sun, Mengmeng, Shi, Peng, Gong, Junbo
Industrial & engineering chemistry process design and development 2018 v.57 no.2 pp. 784-793
case studies, crystallization, histidine, methanol, process design
In this study, the effects of crystal nucleation–growth on subsequent solvent-mediated phase transformation experiments of l-histidine (l-his) in antisolvent crystallization were performed at 298.15 K. The unexpected acceleration of the overall transformation rate in antisolvent crystallization with solution-mediated phase transformation was found for a methanol volume fraction of 0.35 < x₂ < 0.60. Interestingly, concomitant polymorphs were obtained for a methanol volume fraction of 0.30 ⩽ x₂ ⩽ 0.65 in antisolvent crystallization, whereas only form B was observed for other volume fractions of methanol, which indicated that the concomitant polymorphic phenomenon was the main reason for the accelerated transformation rate in antisolvent crystallization. Furthermore, seed-assisted experiments and suspended solution-mediated phase transformation experiments were designed to uncover the role of the nucleation of form A accompanying with form B in the subsequent transformation process.