| Autor: |
Grace Baaklini, Manon Schindler, Lina Yuan, Clément De Saint Jores, Morgane Sanselme, Nicolas Couvrat, Simon Clevers, Philippe Négrier, Denise Mondieig, Valérie Dupray, Yohann Cartigny, Gabin Gbabode, Gerard Coquerel |
| Jazyk: |
angličtina |
| Rok vydání: |
2023 |
| Předmět: |
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| Zdroj: |
Molecules, Vol 28, Iss 20, p 7061 (2023) |
| Druh dokumentu: |
article |
| ISSN: |
1420-3049 |
| DOI: |
10.3390/molecules28207061 |
| Popis: |
It is shown that the presence of hundreds of ppm of water in 1,3-dimethylurea (DMU) powder led to the large depression of the transition temperature between the two enantiotropically related polymorphic forms of DMU (Form II → Form I) from 58 °C to 25 °C, thus explaining the reported discrepancies on this temperature of transition. Importantly, this case study shows that thermodynamics (through the construction of the DMU–water temperature-composition phase diagram) rather than kinetics is responsible for this significant temperature drop. Furthermore, this work also highlights the existence of a monohydrate of DMU that has never been reported before with a non-congruent fusion at 8 °C. Interestingly, its crystal structure, determined from X-ray powder diffraction data at sub-ambient temperature, consists of a DMU–water hydrogen bonded network totally excluding homo-molecular hydrogen bonds (whereas present in forms I and II of DMU). |
| Databáze: |
Directory of Open Access Journals |
| Externí odkaz: |
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