Molecular aspects of glycine clustering and phase separation in an aqueous solution during anti-solvent crystallization

Abstract

<p>The anti-solvent crystallization behavior of the glycine aqueous and ethanol system was addressed through a molecular dynamics simulation of a non-equilibrium state. The rectangular simulation cell was assigned to mimic...</p>

Mesoscale clusters of organic solutes in solution and their role in crystal nucleation

“…77 Alison et al, 52 using a combination of SAXS and WAXD, showed that the compound 2,6-dibromo-4nitroaniline nucleated in two steps, initially as a nondiffractive (amorphous) phase that subsequently became diffractive (crystalline). Based on molecular dynamics simulations, two-step nucleation has been predicted for several systems, including glycine during antisolvent crystallization, 78 and acetic acid from tetrachloromethane during evaporative crystallization. 79 Nucleation from pre-nucleation clusters An alternative, but in many ways similar and at least partly overlapping theory, was developed for nucleation of calcium carbonate in biomineralization processes.…”

Glycine: The Gift that Keeps on Giving

“…Nonphotochemical laser-induced nucleation (NPLIN), [162,[175][176][177][178][179][180][181] and crystallization in electromagnetic fields [182][183][184] have been taken as demonstration of the validity of such a model for the crystallization occurring in supersaturated (and aged) aqueous glycine solutions. The techniques based on changing the rate of increasing supersaturation (antisolvent crystallization, [185][186][187] spray-drying, [188][189][190][191][192] freeze-drying, [193][194][195][196][197] cooling at variable rates [45,198,199] ) suppose using the Ostwald's rule of stages, [200,201] when a metastable form nucleates first and in this way also the batch product can be prepared as a metastable polymorph. At the same time, many studies showed, that the relative rates of the growth of the already formed nuclei, and / or their solvent assistant transformation into other polymorphs are at least equally important.…”

Recent progress in antisolvent crystallization

“…Antisolvent crystallization refers to the category of solution crystallization. 10 Compared with other crystallization modes, several advantages exist in antisolvent crystallization: [11][12][13][14] (i) lower energy consumption in supersaturation control, (ii) small particle size for the targeted products, and (iii) suitable for heat-sensitive materials. The material properties, experimental conditions, and device design are important variables in antisolvent crystallization.…”