Polymorphic phase transitions and melting in (+)-decursinol crystals studied by differential scanning calorimetry

The powder X-ray diffraction (PXRD) and differential scanning calorimetry (DSC) have been conducted both for structural characterization of polycrystalline (+)-decursinol (C14H14O4) and for detecting phase transformations. Using PXRD, the crystal system of decursinol was determined to be orthorhombic with a space group P212121, and the lattice parameters were derived. Upon heating in DSC, two polymorphic phase transitions were recognized as weak endothermic peaks around Tc2+≈ 64 °C and Tc1+≈ 68 °C. Further heating showed a large peak of melting with the extrapolated onset temperature Tm,o ≈ 177 °C.