Adipic Acid Primary Nucleation Kinetics from Probability Distributions in Droplet-Based Systems under Stagnant and Flow Conditions

Abstract

In this work, we present a microfluidic approach that allows performing nucleation studies under different fluid dynamic conditions. We determine primary nucleation rates and nucleation kinetic parameters for adipic acid solutions by using liquid/liquid segmented flow in capillary tubes in which the crystallizing medium is partitioned into small droplets. We do so by measuring the probability of crystal presence within individual droplets under stagnant (motionless droplets) and flow (moving droplets) conditions as a function of time, droplet volume, and supersaturation. Comparing the results of the experiments with the predictions of the classical nucleation theory model and of the mononuclear nucleation mechanism model, we conclude that adipic acid nucleates mainly via a heterogeneous mechanism under both fluid dynamic conditions. Furthermore, we show that the flow conditions enhance the primary nucleation rate by increasing the kinetic parameters of the process without affecting the thermodynamic parameters. In this regard, a possible mechanism is discussed on the basis of the enhancement of the attachment frequency of nucleation caused by the internal recirculation that occurs within moving droplets.

Effect of acoustic streaming on continuous flow sonocrystallization in millifluidic channels

“…In chemical syntheses, ultrasound has been commonly utilized to accelerate reaction kinetics and even develop new synthetic pathways [10]. In the context of crystallization, the use of ultrasound is referred to as sonocrystallization, and ultrasound has been proven to positively influence the kinetics of the various processes involved in the crystal production (in particular the nucleation process), which has several potential benefits [11][12][13][14]:…”

Comparison of the interfacial energy and pre-exponential factor calculated from the induction time and metastable zone width data based on classical nucleation theory

“…As the induction time can be experimentally determined by the isothermal method at a constant supersaturation level, the induction time data are frequently used as a measure of the nucleation event to calculate the interfacial energy of the crystallized substance in the literature [5][6][7][8][9][10][11][12][13].…”

Aromatic stacking – a key step in nucleation

“…Such data can be accumulated via medium throughput methods as in the Crystal16 methodology of Jiang and ter Horst [10] for the evaluation of nucleation rates from induction time measurements. This, and other [11] techniques have enabled an increasing availability of kinetic data relating nucleation rates to supersaturation and solvent choice. However, up until now the systems studied appear to have been chosen at random.…”