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Binary clathrate hydrates with methane (CH4, 4.36 Å) and tert-butylamine (t-BuNH2, 6.72 Å) as guest molecules were synthesized at different molar concentrations of t-BuNH2(1.00−9.31 mol %) with methane at 7.0 MPa and 250 K, and were characterized by powder X-ray diffraction (PXRD) and Raman microscopy. A structural transformation from sVI to sII of t-BuNH2hydrate was clearly observed on pressurizing with methane. The PXRD showed sII signatures and the remnant sVI signatures were insignificant, implying the metastable nature of sVI binary hydrates. Raman spectroscopic data on these binary hydrates suggest that the methane molecules occupy the small cages and vacant large cages. The methane storage capacity in this system was nearly doubled to ∼6.86 wt % for 5.56 mol % > t-BuNH2> 1.0 mol %. [ABSTRACT FROM AUTHOR]

The first proof-of-concept of the formation of a double tert-butylamine (t-BuNH2) + hydrogen (H2) clathrate hydrate has been demonstrated. Binary clathrate hydrates with different molar concentrations of the large guest t-BuNH2(0.98−9.31 mol %) were synthesized at 13.8 MPa and 250 K, and characterized by powder X-ray diffraction and Raman microscopy. A structural transformation from sVI to sII of t-BuNH2hydrate was clearly observed under hydrogen pressures. Raman spectroscopic data suggested that the hydrogen molecules occupied the small cages and had similar occupancy to hydrogen in the double tetrahydrofuran (THF) + H2clathrate hydrate. The hydrogen storage capacity in this system was ∼0.7 H2wt % at the molar concentration of t-BuNH2close to the sII stoichiometry. [ABSTRACT FROM AUTHOR]