Clathrate Hydrates in the Water–Tetrahydropyran System at High Pressure

Tetrahydropyran (THP) forms a clathrate hydrate THP·17H₂O of cubic structure II which melts at P = 1 atm, T= – 0.8°C decomposing into two liquids with an upper consolute temperature of dissolution of 226 °C. It is destabilized by pressure and at P > 1.15 kbar, T= – 4.3°C cubic structure I hydrate appears to become stable.