Nii Susumu, Takayanagi Saki
Department of Chemical Engineering, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8603, Japan.
Department of Chemical Engineering, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8603, Japan.
Ultrason Sonochem. 2014 May;21(3):1182-6. doi: 10.1016/j.ultsonch.2013.11.009. Epub 2013 Dec 1.
Antisolvent crystallization of glycine was performed under ultrasonic irradiation of 1.6 MHz. The irradiation enhanced both the growth of α-glycine crystal and the uniformity in the crystal size. The degree of both enhancement effects increased with increasing ultrasonic power. While under the irradiation of 20 kHz ultrasound, no growth enhancement was observed, but the crystal size reduced as was reported in the literature. To elucidate the mechanism of growth enhancement, another experiment was designed and conducted to avoid the effect of nucleation from the sonocrystallization. The result suggests that the ultrasound enhances the incorporation of microcrystals to larger crystals. Probably, the collision between solid particles is intensified by the disturbance characterized by the high frequency ultrasound. The crystal growth was modeled with an apparent reaction of microcrystal and larger crystal. The result of the growth experiment was successfully predicted with a rate equation for pseudo first order reaction with a single parameter of rate constant. The rate constant linearly increased with the ultrasonic power. The analysis enables quantitative evaluation of the ultrasonic effect on the crystal growth.
在1.6MHz的超声辐照下进行甘氨酸的抗溶剂结晶。该辐照既增强了α-甘氨酸晶体的生长，又提高了晶体尺寸的均匀性。两种增强效果的程度均随超声功率的增加而增加。而在20kHz超声辐照下，未观察到生长增强现象，但晶体尺寸如文献报道的那样减小了。为了阐明生长增强的机制，设计并进行了另一项实验以避免声致结晶成核的影响。结果表明，超声增强了微晶向较大晶体的并入。可能是高频超声所表征的扰动加剧了固体颗粒之间的碰撞。用微晶与较大晶体的表观反应对晶体生长进行建模。用具有速率常数单一参数的伪一级反应速率方程成功预测了生长实验的结果。速率常数随超声功率线性增加。该分析能够对超声对晶体生长的影响进行定量评估。
