Main content area

Ultrasound-Assisted Antisolvent Crystallization of Benzoic Acid: Effect of Process Variables Supported by Theoretical Simulations

Ramisetty, Kiran A., Pandit, Aniruddha B., Gogate, Parag R.
Industrial & Engineering Chemistry Research 2013 v.52 no.49 pp. 17573-17582
benzoic acid, crystallization, growth models, high performance liquid chromatography, impellers, liquids, mixing, simulation models, solutes, solvents, sonication, ultrasonic treatment, ultrasonics, wavelengths
This work investigates the application of ultrasound for improving the antisolvent crystallization of benzoic acid. The main objective of applying ultrasound is to enhance the crystal productivity and modify the morphology as compared to the conventional stirred crystallizer. The effect of the sonication on the crystal size distribution and supersaturation ratio has been investigated. The effect of initial concentration of solvent and antisolvent addition rate on the crystal size and supersaturation ratio has also been studied under conventional mixing and ultrasound for effective comparison. The concentration of the solute in the liquid has been determined using HPLC at 228 nm wavelength so as to determine the supersaturation levels of solute. Dynamic growth kinetics of the crystallization process has been established by measuring the crystal size with respect to time. Dynamic metastable zone width was found by observing the formation of the crystal nuclei indicated by the liquid turning from transparent to slightly turbid. A decrease in the metastable zone width has been observed due to the application of ultrasound. The study of conventional crystallization has been conducted over varying impeller speeds of 400, 500, 600 rpm, and ultrasonic crystallization has been studied over different amplitudes of 40%, 50%, 60% amp using 750 W and 20 kHz frequency horn. Crystal size distribution has been observed to be wider in stirred crystallization process as compared to the ultrasound-assisted operation. Modeling of the process of antisolvent crystallization has been carried out using gProms PSE environment, and the comparison of the simulated results with the experimental results has been presented.