Solvent effects on kinetics of solution-mediated transition of stearic acid polymorphs

Polymorphism of even saturated carboxylic acids from n-decanoic to n-eicosanoic acid

“…Measurements carried out with the A form showed that it was metastable (higher solubilities) over the whole range of temperatures studied. Further experiments carried out by Sato point to the same conclusion: the B and C forms co-exist at certain temperatures (297, 305, and 319 K for C 16 9,[43][44][45] The differences regarding the temperature of the B -C transition between Sato's data (solubility measurements) and the present work (DSC measurements, Table 3) could be attributed to kinetic effects since the solid-state transitions between the polymorphic modifications are kinetically hindered due to certain steric effects involving rearrangements in the molecular conformation and the angle of tilt of the molecules within the cell. 9 To confirm the stability regions determined by solubility experiments, DTA measurements at different pressures in the range 500-1500 bar were performed in order to determine the temperature-pressure equilibrium diagram.…”

Altered phase behavior of the lauric acid–stearic acid binary mixtures in electrospun PVA–PDMS mats

“…48,66 The scatter in the transition temperature data reported by various researchers can be attributed to the presence of a kinetic barrier that may be influenced by the processing parameters such as the heating rate, solvents, and the presence of other components. The B and C forms in SA co-exist at 32 1C, 30,31,34,49,[67][68][69] whereas in LA the solid-solid transitions from A super to C and B to C occur at 35.1 1C and 10.1 1C, respectively. 30,46 We have performed analysis of the DSC thermograms obtained for our samples based on the reported transitions in the literature cited above (see ESI, † Table S2).…”

An approach to solvent screening for crystallization of polymorphic pharmaceuticals and fine chemicals

“…Stearic acid has four polymorphs as A, B, C, and E which can be obtained by crystallization from different solvents 22. Form A, which is an unstable form, can be crystallized from nonpolar solvents such as benzene and Form B can be obtained by crystallization from dipolar protic solvents.…”