Gas-Phase Synthesis and Characterization of CH4-Loaded Hydroquinone Clathrates

Journal Article · Fri Jan 01 04:00:00 EST 2010 · Journal of Physical Chemistry B

DOI:https://doi.org/10.1021/jp911822e· OSTI ID:1019935

Lee, J; Lee, Y; Takeya, S; Kawamura, T; Yamamoto, Y; Lee, Y; Yoon, J

A CH{sub 4}-loaded hydroquinone (HQ) clathrate was synthesized via a gas-phase reaction using the {alpha}-form of crystalline HQ and CH{sub 4} gas at 12 MPa and room temperature. Solid-state {sup 13}C cross-polarization/magic angle spinning (CP/MAS) NMR and Raman spectroscopic measurements confirm the incorporation of CH{sub 4} molecules into the cages of the HQ clathrate framework. The chemical analysis indicates that about 69% of the cages are filled by CH{sub 4} molecules, that is, 0.69 CH{sub 4} per three HQ molecules. Rietveld refinement using synchrotron X-ray powder diffraction (XRD) data shows that the CH{sub 4}-loaded HQ clathrate adopts the {beta}-form of HQ clathrate in a hexagonal space group R3 with lattice parameters of a = 16.6191 {angstrom} and c = 5.5038 {angstrom}. Time-resolved synchrotron XRD and quadrupole mass spectroscopic measurements show that the CH{sub 4}-loaded HQ clathrate is stable up to 368 K and gradually transforms to the {alpha}-form by releasing the confined CH{sub 4} gases between 368-378 K. Using solid-state {sup 13}C CP/MAS NMR, the reaction kinetics between the {alpha}-form HQ and CH{sub 4} gas is qualitatively described in terms of the particle size of the crystalline HQ.

• Research Organization: Brookhaven National Laboratory (BNL) National Synchrotron Light Source
• Sponsoring Organization: DOE - OFFICE OF SCIENCE
• DOE Contract Number: AC02-98CH10886
• OSTI ID: 1019935
• Report Number(s): BNL--95781-2011-JA
• Journal Information: Journal of Physical Chemistry B, Journal Name: Journal of Physical Chemistry B Journal Issue: 9 Vol. 114; ISSN 1520-6106
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
CHEMICAL ANALYSIS
CLATHRATES
DIFFRACTION
GASES
LATTICE PARAMETERS
PARTICLE SIZE
QUADRUPOLES
REACTION KINETICS
SPACE GROUPS
SYNCHROTRONS
SYNTHESIS
X-RAY DIFFRACTION
national synchrotron light source