title: Structural transformation and guest dynamics of methanol-loaded hydroquinone clathrate observed by temperature-dependent Raman spectroscopy.
abstract: The structural transformations and guest dynamics of methanol-loaded β-form hydroquinone (HQ) clathrate were investigated using temperature-dependent Raman spectroscopy. Methanol-loaded β-form HQ clathrate was obtained by recrystallization and characterized by elemental analysis, synchrotron X-ray diffraction, solid-state (13)C NMR spectroscopy, and Raman spectroscopy. Temperature-dependent Raman spectra of methanol-loaded β-form HQ clathrate were measured in the temperature range 300-412 K at increments of 4 K. Although no significant changes were evident in the temperature range 300-376 K, abrupt changes in the relative intensity and shape of the Raman bands were observed between 380 and 412 K indicating the structural transition from methanol-loaded β-form HQ clathrate to pure α-form HQ. Methanol molecules were gradually released from the β-form HQ clathrate in the range 364-380 K. Upon returning to ambient conditions, the crystal structure of the HQ sample remained identical to that of pure α-form HQ. Therefore, the temperature-induced structural transition of methanol-loaded HQ clathrate is completely irreversible and α-form HQ is more stable at ambient conditions.
authors.affiliation: Department of Energy and Resources Engineering, Korea Maritime University, Busan 606-791, Korea.
authors.forename: Byong-Uk
authors.initials: BU
authors.lastname: Nam
authors.forename: Byeong-Soo
authors.initials: BS
authors.lastname: Kim
authors.forename: Hyeong-Hoon
authors.initials: HH
authors.lastname: Lee
authors.forename: Ji-Ho
authors.initials: JH
authors.lastname: Yoon
mesh_terms: D006873:Hydroquinones / Q000737:chemistry*; D000432:Methanol / Q000737:chemistry*; D015394:Molecular Structure; D013059:Spectrum Analysis, Raman; D013696:Temperature; D013816:Thermodynamics
chemical_list: D006873:Hydroquinones; D000432:Methanol