The polymorph and crystal habit control of DL-methionine assisted by ultrasound

In this work, ultrasound was applied to the batch crystallization of DL-methionine, dedicated to developing the strategy to achieve pure metastable form, regular crystal habit, and high yields of DL-methionine. Experimental analyses for batch crystallization were performed to investigate the effects of ultrasound field, supersaturation, and temperature on DL-methionine crystal form. It was found that ultrasound was more conducive to the formation of DL-methionine metastable crystals by promoting nucleation. Moreover, the artificial neural network was used to predict crystal form according to the input of experimental samples. Based on the goal of crystal habit optimization, experiments were designed to find the key factors to control product quality, and the experimental results correspond to the prediction results. It was found that ultrasound could result in high bulk density of the product due to the optimization of crystal habit and crystal size distribution, and the mechanism of ultrasound on crystal habit and yield was investigated. This study provided a deeper insight into the mechanisms of ultrasound on nucleation and crystal growth, which could also be used as an effective strategy to improve the physicochemical properties of a product by applying ultrasound to achieve simultaneous multi-objective optimization.

Automated summary

In this study, the effects of ultrasound field, supersaturation, and temperature on the crystal form of DL-methionine were investigated. Ultrasound was found to promote the formation of metastable crystals and improve the bulk density of the product through optimization of crystal habit and size distribution. The use of artificial neural network for crystal form prediction was also explored.