Solution crystallisation via a submerged liquid–liquid phase boundary: oiling out

Abstract

In many situations the process of crystallisation from solution is known to occur via metastable crystalline states (polymorphs or solvates). Here we present what we believe to be a novel example of small molecule crystallisation in which the initial separation of a solute rich liquid phase precedes the crystallisation event. We believe this occurs because a submerged liquid–liquid phase boundary is accessible within the metastable zone of the crystal nucleation process.