Ultrasound Assisted Particle Size Control by Continuous Seed Generation and Batch Growth

Jordens, Jeroen; Canini, Enio; Gielen, Bjorn; Gerven, Tom Van; Braeken, Leen

doi:10.3390/cryst7070195

Cited by 25 publications

(46 citation statements)

References 51 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The decrease in particle size with increasing supersaturation for the ultrasound probe was likely due to increasing number of nuclei that were formed under high supersaturation, as this generally leads to higher nucleation rates. This phenomenon was previously reported in the literature, and is not limited to ultrasound-induced nucleation, as it is also reported in the absence of ultrasound [5,12,16,34]. However, with increasing nucleation rates, decreased induction times would be expected, which was not the case when considering the induction-time experiments [24].…”

Section: Induction-time Measurementssupporting

confidence: 78%

“…Jordens et al studied seed generation in an ultrasound flow cell with growth in batch for the cooling crystallization of paracetamol. They found that the metastable zone width decreased significantly under sonicated conditions, and that the particle size decreased with increasing initial supersaturation [16]. These studies all indicate the suitability of ultrasound to enhance the nucleation rate in a tubular crystallizer.…”

Section: Introductionmentioning

confidence: 88%

“…After filtration, the crystals were washed with water (23 • C), and particle-size measurements of the crystals were performed using a laser diffractometer (Mastersizer 3000, Malvern Panalytical, Malvern, UK) in hexane. The exact procedure was described elsewhere [16]. …”

Section: Methodsmentioning

confidence: 99%

“…Calorimetric power measurements were performed for both the ultrasound probe and the rotor-stator mixer based on methods described in the literature [16,28,29]. The devices were inserted into a jacketed batch reactor with 200 mL of water.…”

Section: Calorimetric Power Measurementsmentioning

confidence: 99%

“…The mechanism behind sonocrystallization remains unclear; however, most research suggests that the effects are most likely associated with acoustic cavitation. Acoustic cavitation can be divided into stable cavitation, which entails the formation, growth, and oscillation of microbubbles under the influence of ultrasound waves, and transient cavitation, in which these microbubbles also violently collapse [15][16][17].…”

Section: Introductionmentioning

confidence: 99%

See 4 more Smart Citations

Reducing the Induction Time Using Ultrasound and High-Shear Mixing in a Continuous Crystallization Process

et al. 2018

Self Cite

View full text Add to dashboard Cite

Continuous crystallization in tubular crystallizers is of particular interest to the pharmaceutical industry to accurately control average particle size, particle size distribution, and (polymorphic) shape. However, these types of crystallizers require fast nucleation, and thus, short induction times at the beginning of the flow process, which is challenging for larger and complex organic molecules. High shear and/or the presence of bubbles were identified to influence the nucleation behavior. This work investigates the effects of both high-shear mixing and ultrasound on the anti-solvent crystallization of paracetamol in acetone-water. Both devices generate intense amounts of shear and gas bubbles. Generally, the results show that increasing input power decreases the induction time significantly for both the rotor-stator mixer and ultrasound probe. However, the induction time is almost independent of the supersaturation for the ultrasound probe, while the induction time significantly increases with decreasing supersaturation for the rotor-stator mixer. In contrast, the particle size distribution for the rotor-stator mixer is independent of the supersaturation, while increasing supersaturation decreases the particle size for the ultrasound probe.

show abstract

Section: Induction-time Measurementssupporting

confidence: 78%

Section: Introductionmentioning

confidence: 88%

Section: Methodsmentioning

confidence: 99%

Section: Calorimetric Power Measurementsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Reducing the Induction Time Using Ultrasound and High-Shear Mixing in a Continuous Crystallization Process

et al. 2018

Self Cite

View full text Add to dashboard Cite

show abstract

Nucleation in continuous flow cooling sonocrystallization for coiled capillary crystallizers

2021

View full text Add to dashboard Cite

Nucleation in continuously operated capillary coiled cooling crystallizers is experimentally investigated under the influence of ultrasound. It was found that there is no sharp boundary but rather a transition zone for nucleation under sonication. For this purpose, a tube with an inner diameter of 1.6 mm and a length of 6 m was winded in a coiled flow inverter (CFI) design and immersed into a cooled ultrasonic bath (37 kHz). The CFI design was chosen for improved radial mixing and narrow residence time distribution, which is also investigated. Amino acid l-alanine dissolved in deionized water is employed in a supersaturation range of 1.10 to 1.46 under quiet and sonicated conditions. Nucleation is non-invasive detected using a flow cell equipped with a microscope and camera. Graphical abstract Since the interest and demand for small-scale, continuous crystallization increases, seed crystals were generated in a coiled tube via sonication and optically investigated and characterized. No distinct threshold for nucleation could be determined in a wide range of supersaturations of l-alanine in water

show abstract

Effect of acoustic streaming on continuous flow sonocrystallization in millifluidic channels

Valitov

Jamshidi

Rossi

et al. 2020

Chemical Engineering Journal

View full text Add to dashboard Cite

This work is concerned with the effect of ultrasound on mixing and consequently on crystallization in millifluidic channels. An ultrasonic horn with frequency of 20 kHz was placed inside a vessel with a well-defined geometry containing a single capillary tube with internal diameter (I.D.) of 1.55 or 3.2 mm operated with a fluid flow rate between 1 and 17.6 ml/min. This system was employed to produce crystals of adipic acid in the range of 15-35 µm. The effect of ultrasound on flow patterns, residence time distribution (RTD) and cooling crystallization were investigated experimentally and numerically. Simulations of acoustic and velocity fields inside the millichannel acting as crystallizer allowed characterizing the acoustic streaming generated within it. In the large capillary, especially at small flow rates, acoustic streaming influenced the flow field, inducing vortices and leading to significant changes in RTD. Conversely, in the small capillary, ultrasound affected the flow field and the RTD negligibly, and a laminar velocity profile with straight streamlines was obtained. As a consequence, different crystallization behaviours were observed in the two capillaries; in particular, while the mean crystal size increased with the sonication residence time in the 1.55 mm I.D. capillary, it decreased in the 3.2 mm I.D. capillary. This difference highlights the importance of considering acoustic streaming when designing sonocrystallizers.

show abstract

Ultrasound Assisted Particle Size Control by Continuous Seed Generation and Batch Growth

Cited by 25 publications

References 51 publications

Reducing the Induction Time Using Ultrasound and High-Shear Mixing in a Continuous Crystallization Process

Reducing the Induction Time Using Ultrasound and High-Shear Mixing in a Continuous Crystallization Process

Nucleation in continuous flow cooling sonocrystallization for coiled capillary crystallizers

Effect of acoustic streaming on continuous flow sonocrystallization in millifluidic channels

Contact Info

Product

Resources

About