Oiling out or molten hydrate-liquid-liquid phase separation in the system vanillin-water
2007 (English)In: Journal of Pharmaceutical Sciences, ISSN 0022-3549, E-ISSN 1520-6017, Vol. 96, no 9, 2390-2398 p.Article in journal (Refereed) Published
Vanillin crystals in a saturated aqueous solution disappear and a second liquid phase emerges when the temperature is raised above 51 degrees C. The phenomenon has been investigated with crystallization and equilibration experiments, using DSC, TGA, XRD and hot-stage microscopy for analysis. The new liquid solidifies on cooling, appears to melt at 51 degrees C, and has a composition corresponding to a dihydrate. However, no solid hydrate can be detected by XRD, and it is shown that the true explanation is that a liquid-liquid phase separation occurs above 51 degrees C where the vanillin-rich phase has a composition close to a dihydrate. To our knowledge, liquid-liquid phase separation has not previously been reported for the system vanillin-water, even though thousands of tonnes of vanillin are produced globally every year.
Place, publisher, year, edition, pages
2007. Vol. 96, no 9, 2390-2398 p.
calorimetry (DSC), thermogravimetric analysis, thermodynamics, solubility, solid state stability, pseudopolymorphism, polymorphism, hydrates/solvates, crystallization
IdentifiersURN: urn:nbn:se:kth:diva-16931DOI: 10.1002/jps.20899ISI: 000249183800017PubMedID: 17497737ScopusID: 2-s2.0-34748845360OAI: oai:DiVA.org:kth-16931DiVA: diva2:334974