Temperature- and Pressure-Induced Crystallization and Melting of Tetracontane in Propane:  Evidence of Retrograde Crystallization

Abstract

The crystallization and melting transitions for tetracontane in propane, measured in this work at pressures up to about 1200 bar, are found to exhibit a temperature minimum, which implies crystallization upon decompression (retrograde crystallization). The supercooling effect, which is the difference between the crystallization and melting temperature, is found to decrease with increasing tetracontane concentration. The transitions induced by varying temperature at constant pressure are found to fall near the same curve as those induced by varying pressure at constant temperature. The difference between the crystallization and melting pressure represents the super-compression effect.

Phase behaviour in the vicinity of the three-phase solid–liquid–vapour line in asymmetric nonpolar systems at high pressures

“…ment with the results of Łuszczyk and Radosz[3] is very good. The extension of the retrograde region is similar to those observed by Łuszczyk and Radosz.…”

“…However, it is not clear whether the solid-liquid curve is monotonic also in binary mixtures containing lowconcentrations of the heavy component. An example of an unusual shape of the solid-liquid curve in dilute nonpolar mixtures has been reported by Łuszczyk and Radosz [3] for the system propane + tetracontane. In this work for the first time it was shown that in a binary type V mixture it is possible to observe retrograde melting.…”

“…in the literature except those found by Łuszczyk and Radosz [3]. However, careful analysis of the data presented by Peters and his group for the three systems propane + acenaphthene, propane + tetratriacontane and ethane + eicosane revealed that the solid-liquid phase boundaries for mixtures with low concentration of the solute have a negative slope.…”

“…For dilute binary mixtures of naphthalene or tetracosane with methane the solid-vapour boundary at constant composition exhibit temperature minimum [1,2]. However, Łuszczyk and Radosz [3] were the first to show that the solid-liquid phase boundary of a constant composition type V mixture also exhibit the temperature minimum. As a result retrograde melting in these mixtures is observed.…”

Near-Critical Micellization for Nanomedicine: Enhanced Drug Loading, Reduced Burst Release

“…More detailed descriptions are available elsewhere. [13][14][15] The CP is determined to be the inflection point of the TLI curve, which corresponds to a peak in its first derivative. Sample graphs of two typical cases of SLI curves are shown in Figures 13.4 and 13.5.…”