Low-density preference of the ambient and high-pressure polymorphs of DL-menthol.

ABSTRACT: Lower-density polymorphs of DL-menthol were nucleated and crystallized in their high-pressure stability regions. Up to 0.30 GPa, the triclinic DL-menthol polymorph α, which is stable at atmospheric pressure, is less dense than a new β polymorph, which becomes stable above 0.40 GPa, but is less dense than the α polymorph at this pressure. The compression of polymorph α to at least 3.37 GPa is monotonic, with no signs of phase transitions. However, recrystallizations of DL-menthol above 0.40 GPa yield the β polymorph, which is less compressible and becomes less dense than α-DL-menthol. At 0.10 MPa, the melting point of the β polymorph is 14°C, much lower compared with those of α-DL-menthol (42-43°C) and L-menthol (36-38°C). The structures of both DL-menthol polymorphs α and β are very simila

SUBMITTER: Roszak K 

PROVIDER: S-EPMC10161766 | biostudies-literature | 2023 May

REPOSITORIES: biostudies-literature