Polymorphism of anhydrous oxalic acid unravelled

0542947 - FZÚ 2022 RIV GB eng J - Článek v odborném periodiku
Štejfa, V. - Pokorný, V. - Rohlíček, Jan - Fulem, M. - Růžička, K.
Polymorphism of anhydrous oxalic acid unravelled.
Journal of Chemical Thermodynamics. Roč. 160, Sep (2021), č. článku 106488. ISSN 0021-9614. E-ISSN 1096-3626
Grant CEP: GA MŠMT(CZ) EF16_019/0000760
Grant ostatní: OP VVV - SOLID21(XE) CZ.02.1.01/0.0/0.0/16_019/0000760
Institucionální podpora: RVO:68378271
Klíčová slova: oxalic acid * polymorphism * calorimetry * vapor pressures * x-ray powder diffraction
Obor OECD: Condensed matter physics (including formerly solid state physics, supercond.)
Impakt faktor: 3.269, rok: 2021
Způsob publikování: Omezený přístup
https://doi.org/10.1016/j.jct.2021.106488

Despite being a very common compound in the industry as well as in the nature, the thermodynamic description of oxalic acid is far from being complete and reliable. The literature is contradictory considering both preparation of the two known polymorphs and the triple point temperature above which β-form should be more stable. The published vapour pressure data for α-phase show also a considerable disagreement. In this work, the polymorphs of anhydrous oxalic acid are subjected to a combined thermodynamic and X-ray diffraction study since a single technique cannot give an exhaustive answer on the phase behaviour of the compound. The simultaneous correlation procedure that combines vapour pressure data, calorimetric phase-transition properties, and heat capacities of the crystalline and ideal-gas phase is used to develop a consistent thermodynamic description. Finally, the triple point temperature and transition enthalpy are derived.
Trvalý link: http://hdl.handle.net/11104/0320270