Unraveling the Role of Fluid Shear on Primary Nucleation of Paracetamol through an Energy-Dissipation Rate Analysis

Abstract

The effect of fluid shear on the primary nucleation of paracetamol in water, isopropyl alcohol, and acetonitrile was investigated. First, experiments were performed with a Taylor−Couette crystallizer. For all three solvents, a comparable effect of fluid shear on the nucleation kinetics was found: increasing fluid shear results in an increase in the nucleation rate and a decrease in the variability of the induction times. The experimental analysis shows that the mean induction times are dependent on the energy dissipation rate to a power of approximately −1/3. A comparative investigation for paracetamol crystallization in stirred batch crystallizers revealed the same dependence of mean induction times on the energy dissipation rate. Extending this analysis to experimental data sets from the literature confirms this further. To find a physical meaning for this dependency, the results are interpreted in terms of the shear-enhanced mass transfer and shear-enhanced cluster aggregation theories.

Secondary Nucleation of α-Glycine Induced by Fluid Shear Investigated Using a Couette Flow Cell

“…These values can also be compared with those previously reported for laminar Couette flow with similar shear rates and surface-to-volume ratios, which were about 20–100 times higher but at a significantly higher supersaturation ( S = 1.4). These results are consistent with previous observations that overall primary nucleation rates (per vessel) JV at given supersaturation and temperature can be expected to depend not only on solution volume V but also on the solution agitation and resulting fluid shear, ,− as well as solution interfacial area and materials of construction involved. ,, …”

Acoustic Streaming to Control the Nucleation Kinetics of Paracetamol in a Tubular Microcrystallizer

“…Fluid shear is known to impact nucleation of small to medium sized organic molecules. − Therefore, the acoustic streaming microcrystallizer was characterized to quantify the shear rate generated by the steady-state acoustic streaming for various ultrasonic powers and frequencies. Then, the effect of the streaming on nucleation of paracetamol from an aqueous solution was evaluated.…”