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Kazunari Ohgaki - One of the best experts on this subject based on the ideXlab platform.
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Storage capacity of hydrogen in Tetrahydrofuran hydrate
Chemical Engineering Science, 2008Co-Authors: Kyohei Ogata, Shunsuke Hashimoto, Takeshi Sugahara, Hiroshi Sato, Masato Moritoki, Kazunari OhgakiAbstract:Abstract The storage capacity of hydrogen in Tetrahydrofuran hydrate was investigated by means of pressure–volume–temperature ( p – V – T ) measurement and Raman spectroscopic analysis. We carried out two measurement strategies using Raman spectroscopic analysis. One was isothermal pressure-swing absorption using Tetrahydrofuran hydrate at 277.15 K, and the other was the preparation of a single crystal of hydrogen+Tetrahydrofuran mixed gas hydrate from compressed hydrogen and Tetrahydrofuran aqueous solutions along the stability boundary. The storage amount of hydrogen at 277.15 K obtained from the p – V – T measurement is about 1.6 mol (hydrogen)/mol (Tetrahydrofuran) (about 0.8 mass%) at 70 MPa, and isothermal Raman spectroscopic measurement reveals that it reaches the maximum value of 2.0 mol (hydrogen)/mol (Tetrahydrofuran) at about 85 MPa. These results agree well with those for a single crystal of hydrogen+Tetrahydrofuran hydrate.
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thermodynamic stability of h2 Tetrahydrofuran mixed gas hydrate in nonstoichiometric aqueous solutions
Journal of Chemical & Engineering Data, 2007Co-Authors: Shunsuke Hashimoto, Takeshi Sugahara, Hiroshi Sato, Kazunari OhgakiAbstract:Phase equilibria (pressure−temperature relations) of the H2 + Tetrahydrofuran mixed gas hydrate system have been measured for various concentrations of Tetrahydrofuran aqueous solutions. The three-phase equilibrium lines obtained in the present study are shifted to the low-temperature or high-pressure side from that of the stoichiometric THF solution. Each three-phase equilibrium line of H2 + Tetrahydrofuran hydrate converges at the three-phase equilibrium line of the pure Tetrahydrofuran hydrate. At the cross point on the lines, the Tetrahydrofuran concentration of mother aqueous solution agrees with each other. The Raman spectra of H2 and Tetrahydrofuran for the H2 + Tetrahydrofuran mixed gas hydrate do not change with the variation of Tetrahydrofuran mole fraction from 0.010 to 0.130 in the aqueous solution.
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thermodynamic and raman spectroscopic studies on h2 Tetrahydrofuran water and h2 tetra n butyl ammonium bromide water mixtures containing gas hydrates
Chemical Engineering Science, 2006Co-Authors: Shunsuke Hashimoto, Takeshi Sugahara, Hiroshi Sato, Shu Murayama, Kazunari OhgakiAbstract:Phase equilibrium curves of H2+H2+ Tetrahydrofuran and H2+H2+ tetra-n-butyl ammonium bromide mixed gas hydrates were measured in a pressure range from 0.1 to 13.6 MPa. Each three-phase equilibrium curve converges at the maximum temperature point of pure Tetrahydrofuran and tetra-n-butyl ammonium bromide hydrates, respectively. The difference of maximum temperatures is about 8 K, that is, the equilibrium curve of H2+H2+ tetra-n -butyl ammonium bromide mixed gas hydrate shifts to the high-temperature side from that of H2+H2+ Tetrahydrofuran mixed gas hydrate. It is directly confirmed by use of Raman spectroscopy that H2H2 is enclathrated in the hydrate cages by adding a small amount of Tetrahydrofuran or tetra-n -butyl ammonium bromide. In both mixed hydrates, H2H2 is enclathrated in only the small cage while Tetrahydrofuran or tetra-n-butyl ammonium bromide occupies the large cages of each mixed hydrate.
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Stability Boundaries of Tetrahydrofuran + Water System
Journal of Chemical & Engineering Data, 2005Co-Authors: Takashi Makino, And Takeshi Sugahara, Kazunari OhgakiAbstract:Phase equilibria for the Tetrahydrofuran + water system below atmospheric pressure were investigated in a temperature range from 272 K to 278 K. The three-phase (structure-II hydrate + aqueous solution + gas) equilibrium curve has a maximum temperature at 277.45 ± 0.02 K and a pressure of 4.9 ± 0.1 kPa. At this condition, the equilibrium Tetrahydrofuran composition of aqueous solution is equal to the stoichiometric ratio of Tetrahydrofuran hydrate (structure-II). The Tetrahydrofuran hydrate does not coexist with the gas phase beyond 277.45 K. The four-phase (structure-II hydrate + aqueous solution + ice Ih + gas) equilibrium point exists at 272.06 ± 0.02 K and 1.1 ± 0.1 kPa, and the equilibrium Tetrahydrofuran mole fraction of aqueous solution is 0.0106 ± 0.0002.
Shunsuke Hashimoto - One of the best experts on this subject based on the ideXlab platform.
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Storage capacity of hydrogen in Tetrahydrofuran hydrate
Chemical Engineering Science, 2008Co-Authors: Kyohei Ogata, Shunsuke Hashimoto, Takeshi Sugahara, Hiroshi Sato, Masato Moritoki, Kazunari OhgakiAbstract:Abstract The storage capacity of hydrogen in Tetrahydrofuran hydrate was investigated by means of pressure–volume–temperature ( p – V – T ) measurement and Raman spectroscopic analysis. We carried out two measurement strategies using Raman spectroscopic analysis. One was isothermal pressure-swing absorption using Tetrahydrofuran hydrate at 277.15 K, and the other was the preparation of a single crystal of hydrogen+Tetrahydrofuran mixed gas hydrate from compressed hydrogen and Tetrahydrofuran aqueous solutions along the stability boundary. The storage amount of hydrogen at 277.15 K obtained from the p – V – T measurement is about 1.6 mol (hydrogen)/mol (Tetrahydrofuran) (about 0.8 mass%) at 70 MPa, and isothermal Raman spectroscopic measurement reveals that it reaches the maximum value of 2.0 mol (hydrogen)/mol (Tetrahydrofuran) at about 85 MPa. These results agree well with those for a single crystal of hydrogen+Tetrahydrofuran hydrate.
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thermodynamic stability of h2 Tetrahydrofuran mixed gas hydrate in nonstoichiometric aqueous solutions
Journal of Chemical & Engineering Data, 2007Co-Authors: Shunsuke Hashimoto, Takeshi Sugahara, Hiroshi Sato, Kazunari OhgakiAbstract:Phase equilibria (pressure−temperature relations) of the H2 + Tetrahydrofuran mixed gas hydrate system have been measured for various concentrations of Tetrahydrofuran aqueous solutions. The three-phase equilibrium lines obtained in the present study are shifted to the low-temperature or high-pressure side from that of the stoichiometric THF solution. Each three-phase equilibrium line of H2 + Tetrahydrofuran hydrate converges at the three-phase equilibrium line of the pure Tetrahydrofuran hydrate. At the cross point on the lines, the Tetrahydrofuran concentration of mother aqueous solution agrees with each other. The Raman spectra of H2 and Tetrahydrofuran for the H2 + Tetrahydrofuran mixed gas hydrate do not change with the variation of Tetrahydrofuran mole fraction from 0.010 to 0.130 in the aqueous solution.
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thermodynamic and raman spectroscopic studies on h2 Tetrahydrofuran water and h2 tetra n butyl ammonium bromide water mixtures containing gas hydrates
Chemical Engineering Science, 2006Co-Authors: Shunsuke Hashimoto, Takeshi Sugahara, Hiroshi Sato, Shu Murayama, Kazunari OhgakiAbstract:Phase equilibrium curves of H2+H2+ Tetrahydrofuran and H2+H2+ tetra-n-butyl ammonium bromide mixed gas hydrates were measured in a pressure range from 0.1 to 13.6 MPa. Each three-phase equilibrium curve converges at the maximum temperature point of pure Tetrahydrofuran and tetra-n-butyl ammonium bromide hydrates, respectively. The difference of maximum temperatures is about 8 K, that is, the equilibrium curve of H2+H2+ tetra-n -butyl ammonium bromide mixed gas hydrate shifts to the high-temperature side from that of H2+H2+ Tetrahydrofuran mixed gas hydrate. It is directly confirmed by use of Raman spectroscopy that H2H2 is enclathrated in the hydrate cages by adding a small amount of Tetrahydrofuran or tetra-n -butyl ammonium bromide. In both mixed hydrates, H2H2 is enclathrated in only the small cage while Tetrahydrofuran or tetra-n-butyl ammonium bromide occupies the large cages of each mixed hydrate.
Takeshi Sugahara - One of the best experts on this subject based on the ideXlab platform.
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Storage capacity of hydrogen in Tetrahydrofuran hydrate
Chemical Engineering Science, 2008Co-Authors: Kyohei Ogata, Shunsuke Hashimoto, Takeshi Sugahara, Hiroshi Sato, Masato Moritoki, Kazunari OhgakiAbstract:Abstract The storage capacity of hydrogen in Tetrahydrofuran hydrate was investigated by means of pressure–volume–temperature ( p – V – T ) measurement and Raman spectroscopic analysis. We carried out two measurement strategies using Raman spectroscopic analysis. One was isothermal pressure-swing absorption using Tetrahydrofuran hydrate at 277.15 K, and the other was the preparation of a single crystal of hydrogen+Tetrahydrofuran mixed gas hydrate from compressed hydrogen and Tetrahydrofuran aqueous solutions along the stability boundary. The storage amount of hydrogen at 277.15 K obtained from the p – V – T measurement is about 1.6 mol (hydrogen)/mol (Tetrahydrofuran) (about 0.8 mass%) at 70 MPa, and isothermal Raman spectroscopic measurement reveals that it reaches the maximum value of 2.0 mol (hydrogen)/mol (Tetrahydrofuran) at about 85 MPa. These results agree well with those for a single crystal of hydrogen+Tetrahydrofuran hydrate.
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thermodynamic stability of h2 Tetrahydrofuran mixed gas hydrate in nonstoichiometric aqueous solutions
Journal of Chemical & Engineering Data, 2007Co-Authors: Shunsuke Hashimoto, Takeshi Sugahara, Hiroshi Sato, Kazunari OhgakiAbstract:Phase equilibria (pressure−temperature relations) of the H2 + Tetrahydrofuran mixed gas hydrate system have been measured for various concentrations of Tetrahydrofuran aqueous solutions. The three-phase equilibrium lines obtained in the present study are shifted to the low-temperature or high-pressure side from that of the stoichiometric THF solution. Each three-phase equilibrium line of H2 + Tetrahydrofuran hydrate converges at the three-phase equilibrium line of the pure Tetrahydrofuran hydrate. At the cross point on the lines, the Tetrahydrofuran concentration of mother aqueous solution agrees with each other. The Raman spectra of H2 and Tetrahydrofuran for the H2 + Tetrahydrofuran mixed gas hydrate do not change with the variation of Tetrahydrofuran mole fraction from 0.010 to 0.130 in the aqueous solution.
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thermodynamic and raman spectroscopic studies on h2 Tetrahydrofuran water and h2 tetra n butyl ammonium bromide water mixtures containing gas hydrates
Chemical Engineering Science, 2006Co-Authors: Shunsuke Hashimoto, Takeshi Sugahara, Hiroshi Sato, Shu Murayama, Kazunari OhgakiAbstract:Phase equilibrium curves of H2+H2+ Tetrahydrofuran and H2+H2+ tetra-n-butyl ammonium bromide mixed gas hydrates were measured in a pressure range from 0.1 to 13.6 MPa. Each three-phase equilibrium curve converges at the maximum temperature point of pure Tetrahydrofuran and tetra-n-butyl ammonium bromide hydrates, respectively. The difference of maximum temperatures is about 8 K, that is, the equilibrium curve of H2+H2+ tetra-n -butyl ammonium bromide mixed gas hydrate shifts to the high-temperature side from that of H2+H2+ Tetrahydrofuran mixed gas hydrate. It is directly confirmed by use of Raman spectroscopy that H2H2 is enclathrated in the hydrate cages by adding a small amount of Tetrahydrofuran or tetra-n -butyl ammonium bromide. In both mixed hydrates, H2H2 is enclathrated in only the small cage while Tetrahydrofuran or tetra-n-butyl ammonium bromide occupies the large cages of each mixed hydrate.
Hiroshi Sato - One of the best experts on this subject based on the ideXlab platform.
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Storage capacity of hydrogen in Tetrahydrofuran hydrate
Chemical Engineering Science, 2008Co-Authors: Kyohei Ogata, Shunsuke Hashimoto, Takeshi Sugahara, Hiroshi Sato, Masato Moritoki, Kazunari OhgakiAbstract:Abstract The storage capacity of hydrogen in Tetrahydrofuran hydrate was investigated by means of pressure–volume–temperature ( p – V – T ) measurement and Raman spectroscopic analysis. We carried out two measurement strategies using Raman spectroscopic analysis. One was isothermal pressure-swing absorption using Tetrahydrofuran hydrate at 277.15 K, and the other was the preparation of a single crystal of hydrogen+Tetrahydrofuran mixed gas hydrate from compressed hydrogen and Tetrahydrofuran aqueous solutions along the stability boundary. The storage amount of hydrogen at 277.15 K obtained from the p – V – T measurement is about 1.6 mol (hydrogen)/mol (Tetrahydrofuran) (about 0.8 mass%) at 70 MPa, and isothermal Raman spectroscopic measurement reveals that it reaches the maximum value of 2.0 mol (hydrogen)/mol (Tetrahydrofuran) at about 85 MPa. These results agree well with those for a single crystal of hydrogen+Tetrahydrofuran hydrate.
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thermodynamic stability of h2 Tetrahydrofuran mixed gas hydrate in nonstoichiometric aqueous solutions
Journal of Chemical & Engineering Data, 2007Co-Authors: Shunsuke Hashimoto, Takeshi Sugahara, Hiroshi Sato, Kazunari OhgakiAbstract:Phase equilibria (pressure−temperature relations) of the H2 + Tetrahydrofuran mixed gas hydrate system have been measured for various concentrations of Tetrahydrofuran aqueous solutions. The three-phase equilibrium lines obtained in the present study are shifted to the low-temperature or high-pressure side from that of the stoichiometric THF solution. Each three-phase equilibrium line of H2 + Tetrahydrofuran hydrate converges at the three-phase equilibrium line of the pure Tetrahydrofuran hydrate. At the cross point on the lines, the Tetrahydrofuran concentration of mother aqueous solution agrees with each other. The Raman spectra of H2 and Tetrahydrofuran for the H2 + Tetrahydrofuran mixed gas hydrate do not change with the variation of Tetrahydrofuran mole fraction from 0.010 to 0.130 in the aqueous solution.
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thermodynamic and raman spectroscopic studies on h2 Tetrahydrofuran water and h2 tetra n butyl ammonium bromide water mixtures containing gas hydrates
Chemical Engineering Science, 2006Co-Authors: Shunsuke Hashimoto, Takeshi Sugahara, Hiroshi Sato, Shu Murayama, Kazunari OhgakiAbstract:Phase equilibrium curves of H2+H2+ Tetrahydrofuran and H2+H2+ tetra-n-butyl ammonium bromide mixed gas hydrates were measured in a pressure range from 0.1 to 13.6 MPa. Each three-phase equilibrium curve converges at the maximum temperature point of pure Tetrahydrofuran and tetra-n-butyl ammonium bromide hydrates, respectively. The difference of maximum temperatures is about 8 K, that is, the equilibrium curve of H2+H2+ tetra-n -butyl ammonium bromide mixed gas hydrate shifts to the high-temperature side from that of H2+H2+ Tetrahydrofuran mixed gas hydrate. It is directly confirmed by use of Raman spectroscopy that H2H2 is enclathrated in the hydrate cages by adding a small amount of Tetrahydrofuran or tetra-n -butyl ammonium bromide. In both mixed hydrates, H2H2 is enclathrated in only the small cage while Tetrahydrofuran or tetra-n-butyl ammonium bromide occupies the large cages of each mixed hydrate.
S Mukherjee - One of the best experts on this subject based on the ideXlab platform.
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titanocene iii chloride mediated stereoselective synthesis of trisubstituted Tetrahydrofurans and a spirolactone by tandem radical reactions
European Journal of Organic Chemistry, 2014Co-Authors: S MukherjeeAbstract:The titanocene(III) chloride (Cp2TiCl) mediated stereoselective synthesis of highly substituted Tetrahydrofurans has been achieved by a reaction that proceeds through a tandem radical cyclization reaction between a Baylis–Hillman adduct and an activated bromo/iodo compound. The reaction of an epoxide with the Baylis–Hillman adduct furnished a spirolactone through a radical cyclization followed by an in situ lactonization. Cp2TiCl was prepared in situ from commercially available Cp2TiCl2 and zinc dust in Tetrahydrofuran.