Towards an optimized crystallization with ultrasound: Effect of solvent properties and ultrasonic process parameters

Ultrasound has been applied to crystallizing systems, offering a significant potential for modifying and improving both processes and products. As the cavitation generated by ultrasound plays a major role in inducing and controlling nucleation, the influence of the solvent properties such as vapor pressure and surface tension on the crystallization behavior of dodecandioic acid in different solvents (acetonitrile, propyl acetate, and ethyl acetate) was investigated as well as the effect of varying process parameters (power output and frequency). The results show that the solvent properties do not have influence on the reduction of metastable-zone width when ultrasound is applied. On the other hand, the behavior of sonocrystallization is affected by the ultrasonic parameters. An optimal condition of using ultrasound during crystallization to achieve a narrow crystal-size distribution turns out to depend strongly on the supersaturation ratio at which the ultrasound is applied.