Issue 17, 2021

Influence of solution chemistry on the solubility, crystallisability and nucleation behaviour of eicosane in toluene : acetone mixed-solvents

Abstract

The interplay between the solution chemistry and crystallisability of eicosane in mixed toluene : acetone solutions is examined over the full compositional range from pure toluene to pure acetone, using a combination of polythermal crystallisation experiments and molecular modelling. Enthalpies of dissolution and mixing, as well as metastable zone widths increase with increasing acetone content, up to a mol fraction of 0.85 acetone, followed by a decrease in values to pure acetone solutions. Nucleation is found to occur via an instantaneous pathway for the pure solvent systems and also when toluene is in excess, in contrast to solutions where acetone is in excess, which are found to nucleate progressively. Rationalisation through molecular modelling highlights likely changes in the solution structure, whereby eicosane can be expected to be preferentially solvated by toluene, with this solvated cluster being surrounded by a ‘cage’ of acetone molecules. This proposed structure is consistent with a model whereby solute diffusion and hence clustering is hindered when acetone is in excess, decreasing the crystallisability of the solution and effecting a change in the mechanism of nucleation. However, above a critical acetone composition, the potential for complete toluene solvation is restricted and easier crystallisation is enabled.

Graphical abstract: Influence of solution chemistry on the solubility, crystallisability and nucleation behaviour of eicosane in toluene : acetone mixed-solvents

Supplementary files

Article information

Article type
Paper
Submitted
06 mar 2021
Accepted
31 mar 2021
First published
01 abr 2021
This article is Open Access
Creative Commons BY license

CrystEngComm, 2021,23, 3109-3125

Influence of solution chemistry on the solubility, crystallisability and nucleation behaviour of eicosane in toluene : acetone mixed-solvents

P. L. Kaskiewicz, I. Rosbottom, D. M. Camacho Corzo, R. B. Hammond, R. Downie, P. J. Dowding, N. George and K. J. Roberts, CrystEngComm, 2021, 23, 3109 DOI: 10.1039/D1CE00322D

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