Crystallisation of organic hydrates by sublimation

A series of five organic molecules with known crystalline hydrates were sublimed under vacuum in the presence and absence of water. In two systems, crystals of the hydrate could easily be grown from sublimation. Generally, a mixture of hydrated and anhydrous forms were obtained from sublimation. In several cases, an increase in the quantity of water added to the sublimation system resulted in an increase in water content of the sublimed crystals. Competition studies demonstrated that transfer of water can take place between hydrate and anhydrous forms during a sublimation experiment. Hydrates of organic molecules can be crystallised by sublimation if there is a strong hydrogen bond to water in the solid hydrate.

Automated summary

This study investigates the sublimation process of organic molecules with known crystalline hydrates under vacuum and finds that the hydrate crystals can be grown through sublimation. The results show that the water content and the conversion between hydrates and anhydrous forms are influenced by the amount of water present. Sublimation crystallization of hydrates is possible if there is a strong hydrogen bond to water in the solid hydrate.