The influence of solution environment on the nucleation kinetics and crystallisability of para-aminobenzoic acid

Abstract

The influence of solvent type on the solution thermodynamics, nucleation-kinetics and crystal growth of alpha para-aminobenzoic acid (PABA) crystallising from supersaturated ethanol, acetonitrile and water solutions, is examined using poly-thermal analysis of the metastable

Effect of Crystallization Conditions on the Metastable Zone Width and Nucleation Kinetics of p‐Aminobenzoic Acid in Ethanol

“…The values of n for both agitation speeds were less than 1, which indicates that the growth of crystallites in the system was limited only by the mass transfer rate. The present values of c 0 reveal a good agreement with those calculated by the same methodology in using crystallization data for α ‐pABA in 1.5‐mL vials.…”

“…A number of studies , have been carried out previously in order to determine the MSZW in stirred‐tank crystallizers using variable cooling rates, agitation rates, and solution concentrations for different organic/inorganic compounds. These studies have revealed that the MSZW becomes wider as the cooling rate increases, implying that the crystallization temperature decreases with increasing cooling rate.…”

“…Turner et al. found that in the crystallization of p ‐aminobenzoic acid from three different solvents, namely, ethanol, acetonitrile, and water, in 1.5‐mL agitated vials, at a higher solute concentration nucleation occurred via the instantaneous nucleation mechanism, whilst a progressive nucleation took place at a lower concentration.…”

“…This investigation focuses on the crystallization characteristics of p ‐aminobenzoic (pABA) acid in ethanol, particularly the effect of cooling and agitation rates on the MSZW and nucleation mechanism and kinetics. Although several groups , , , investigated the effects that cooling rates exert on the onset of nucleation and nucleation kinetics of pABA, these studies were carried out in very small volumes such as in vials and in droplets. The hydrodynamic and mixing conditions in such systems are not representative of large‐scale stirred‐tank crystallizers with a typical industrial configuration.…”

“…There has been a limited application of the first principles‐based KBHR approach for characterizing the nucleation process of pABA , . In this study, crystallization and dissolution temperatures were measured as a function of cooling rate and impeller speed for the batch cooling crystallization of alpha pABA ( α ‐pABA) from ethanol.…”