The Experts below are selected from a list of 273 Experts worldwide ranked by ideXlab platform
Hajime Tanaka - One of the best experts on this subject based on the ideXlab platform.
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Time-Resolved Light Scattering Study on the Kinetics of the Liquid-Liquid Transition in Triphenyl Phosphite.
The journal of physical chemistry. B, 2015Co-Authors: Mika Kobayashi, Ryotaro Shimizu, Hajime TanakaAbstract:There is experimental evidence suggesting the existence of a liquid–liquid transition (LLT) in a single-component liquid. However, none of this evidence is free from controversy, including the case of a molecular liquid, Triphenyl Phosphite, which we study here. Furthermore, the kinetics of LLT has been largely unexplored. Here we study the phase-transition dynamics of Triphenyl Phosphite in a supercooled liquid state by means of time-resolved polarized and depolarized small-angle light scattering to clarify whether the transition is a liquid–liquid transition (LLT) or merely nanocrystal formation. A part of this study was recently reported in another of our papers [Shimizu, R.; Kobayashi, M.; Tanaka, H. Phys. Rev. Lett. 2014, 112, 125702]. A detailed analysis of our experimental results of light scattering and the comparison with heat evolution during LLT have revealed the following facts. The polarized scattering from domains has a finite (nonzero) intensity in the low-wavenumber limit, and the time evo...
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Time-Resolved Light Scattering Study on the Kinetics of the Liquid–Liquid Transition in Triphenyl Phosphite B
The Journal of Physical Chemistry, 2015Co-Authors: Mika Kobayashi, Ryotaro Shimizu, Hajime TanakaAbstract:There is experimental evidence suggesting the existence of a liquid–liquid transition (LLT) in a single-component liquid. However, none of this evidence is free from controversy, including the case of a molecular liquid, Triphenyl Phosphite, which we study here. Furthermore, the kinetics of LLT has been largely unexplored. Here we study the phase-transition dynamics of Triphenyl Phosphite in a supercooled liquid state by means of time-resolved polarized and depolarized small-angle light scattering to clarify whether the transition is a liquid–liquid transition (LLT) or merely nanocrystal formation. A part of this study was recently reported in another of our papers [Shimizu, R.; Kobayashi, M.; Tanaka, H. Phys. Rev. Lett. 2014, 112, 125702]. A detailed analysis of our experimental results of light scattering and the comparison with heat evolution during LLT have revealed the following facts. The polarized scattering from domains has a finite (nonzero) intensity in the low-wavenumber limit, and the time evolution of its average intensity is almost proportional to the square of the heat-releasing rate. The depolarized scattering intensity monotonically increases in the process of LLT during isothermal annealing above the spinodal temperature TSD but exhibits a peak below TSD. On the basis of these results, we suggest that the primary process is LLT, whose order parameter is of a nonconserved nature, but accompanies nanocrystal formation. In the NG-type LLT, the sharp interface between liquid II droplets and the liquid I matrix promotes nanocrystal formation there, whereas much less nanocrystal formation is induced in the SD-type LLT due to the lack of such sharp interfaces.
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time resolved light scattering study on the kinetics of the liquid liquid transition in Triphenyl Phosphite b
The Journal of Physical Chemistry, 2015Co-Authors: Mika Kobayashi, Ryotaro Shimizu, Hajime TanakaAbstract:There is experimental evidence suggesting the existence of a liquid–liquid transition (LLT) in a single-component liquid. However, none of this evidence is free from controversy, including the case of a molecular liquid, Triphenyl Phosphite, which we study here. Furthermore, the kinetics of LLT has been largely unexplored. Here we study the phase-transition dynamics of Triphenyl Phosphite in a supercooled liquid state by means of time-resolved polarized and depolarized small-angle light scattering to clarify whether the transition is a liquid–liquid transition (LLT) or merely nanocrystal formation. A part of this study was recently reported in another of our papers [Shimizu, R.; Kobayashi, M.; Tanaka, H. Phys. Rev. Lett. 2014, 112, 125702]. A detailed analysis of our experimental results of light scattering and the comparison with heat evolution during LLT have revealed the following facts. The polarized scattering from domains has a finite (nonzero) intensity in the low-wavenumber limit, and the time evolution of its average intensity is almost proportional to the square of the heat-releasing rate. The depolarized scattering intensity monotonically increases in the process of LLT during isothermal annealing above the spinodal temperature TSD but exhibits a peak below TSD. On the basis of these results, we suggest that the primary process is LLT, whose order parameter is of a nonconserved nature, but accompanies nanocrystal formation. In the NG-type LLT, the sharp interface between liquid II droplets and the liquid I matrix promotes nanocrystal formation there, whereas much less nanocrystal formation is induced in the SD-type LLT due to the lack of such sharp interfaces.
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Dynamic Nature of the Liquid-Liquid Transition of Triphenyl Phosphite Studied by Simultaneous Measurements of Dielectric and Morphological Evolution
AIP Conference Proceedings, 2008Co-Authors: Ken-ichiro Murata, Rei Kurita, Hajime TanakaAbstract:We performed broadband dielectric measurements for the process of liquid‐liquid transformation in Triphenyl Phosphite (TPP). According to our dielectric measurements, the static dielectric constant monotonically decreases and the distribution of the relaxation time becomes broader during the liquid‐liquid transformation from liquid I to II. The direct comparison with morphological evolution provides key information on the dynamical and structural evolution during LLT.
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Microscopic structural evolution during the liquid-liquid transition in Triphenyl Phosphite
Journal of Physics: Condensed Matter, 2007Co-Authors: Rei Kurita, Yuya Shinohara, Yoshiyuki Amemiya, Hajime TanakaAbstract:Recently the liquid?liquid transition (LLT) was found in a molecular liquid, Triphenyl Phosphite, which allows us to follow the kinetics of the transformation of one liquid to another. Here we investigate the microscopic structural change during the LLT by means of time-resolved synchrotron x-ray scattering measurements. We confirm that during spinodal-decomposition-type transformation a new peak corresponding to a particular intermolecular phosphor?phosphor distance emerges and grows with time. This indicates that short-range order develops in the liquid during LLT. We show that the short-range order does not represent the crystalline structure, but the locally favoured structure. We found that the temporal increase of the intensity of this peak, i.e., the fraction of locally favoured structures, is proportional to that of the heat released during the transformation. This means that the formation of locally favoured structures is the origin of the heat release. This is consistent with the proposal that the order parameter governing LLT is the number density of locally favoured structures. This yields a valuable insight into the nature of the ordering in the liquid?liquid transition.
Howard Alper - One of the best experts on this subject based on the ideXlab platform.
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Chemo- and Regioselective Cyclohydrocarbonylation of α-Keto Alkynes Catalyzed by a Zwitterionic Rhodium Complex and Triphenyl Phosphite
The Journal of organic chemistry, 2000Co-Authors: Bernard G. Van Den Hoven, And Bassam El Ali, Howard AlperAbstract:α-Keto alkynes react with CO and H2 in the presence of catalytic quantities of the zwitterionic rhodium complex (η6-C6H5BPh3)-Rh+(1,5-COD) and Triphenyl Phosphite affording either the 2-, 2(3H)-, or 2(5H)-furanones in 61−93% yields. The cyclohydrocarbonylation is readily accomplished using substrates containing alkyl, aryl, vinyl, and alkoxy groups at the acetylenic terminal, as well as a variety of primary, secondary, and tertiary alkyl, aryl, and heteroaryl groups connected to the ketone functionality. Structural and electronic properties present in the starting materials mediate the chemo- and regioselectivity of the reaction.
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Regioselective Hydroformylation of Enynes Catalyzed by a Zwitterionic Rhodium Complex and Triphenyl Phosphite
The Journal of Organic Chemistry, 1999Co-Authors: Bernard G. Van Den Hoven And, Howard AlperAbstract:The reaction of aliphatic 1-en-3-ynes with synthesis gas in the presence of the zwitterionic rhodium complex (η6-C6H5BPh3)-Rh+(1,5-COD) and Triphenyl Phosphite affords formyl dienes in high stereoselectivity. This catalytic system provides a useful method for the hydroformylation of both nonfunctionalized and functionalized conjugated enynes under mild conditions, affording formyl dienes in moderate to good yields.
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The First Regioselective Hydroformylation of Acetylenic Thiophenes Catalyzed by a Zwitterionic Rhodium Complex and Triphenyl Phosphite
The Journal of Organic Chemistry, 1999Co-Authors: Bernard G. Van Den Hoven And, Howard AlperAbstract:The hydroformylation of acetylenic thiophenes is readily accomplished by using the zwitterionic rhodium catalyst (η6-C6H5BPh3)-Rh+(1,5-COD) and Triphenyl Phosphite in the presence of CO and H2. This catalytic system affords, as the major product, the α,β-unsaturated aldehyde with the aldehyde and thiophene attached to the same olefin carbon atom. Assistance of sulfur from the heterocycle provides excellent regioselectivity and yields when the acetylenic unit is a propargyl ether or ester, phenylacetylene, or an enyne.
Katsuo Murata - One of the best experts on this subject based on the ideXlab platform.
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thermal study on the impurity effect on thermodynamic stability of the glacial phase in Triphenyl Phosphite Triphenyl phosphate system
Thermochimica Acta, 2005Co-Authors: Ikue Tanabe, Kiyoshi Takeda, Katsuo MurataAbstract:Abstract To investigate the impurity effect on thermodynamic stability of the glacial phase, an apparently amorphous metastable phase observed in Triphenyl Phosphite (TPP), the differential scanning calorimetry (DSC) was carried out in the temperature range 120–350 K for binary mixtures between TPP and Triphenyl phosphate (TPPO). Heating up from the glassy liquid, supercooled liquid phase transformed into glacial phase below the crystallization temperature for all the samples with x
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Thermal study on the impurity effect on thermodynamic stability of the glacial phase in Triphenyl Phosphite–Triphenyl phosphate system
Thermochimica Acta, 2005Co-Authors: Ikue Tanabe, Kiyoshi Takeda, Katsuo MurataAbstract:Abstract To investigate the impurity effect on thermodynamic stability of the glacial phase, an apparently amorphous metastable phase observed in Triphenyl Phosphite (TPP), the differential scanning calorimetry (DSC) was carried out in the temperature range 120–350 K for binary mixtures between TPP and Triphenyl phosphate (TPPO). Heating up from the glassy liquid, supercooled liquid phase transformed into glacial phase below the crystallization temperature for all the samples with x
Mika Kobayashi - One of the best experts on this subject based on the ideXlab platform.
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Time-Resolved Light Scattering Study on the Kinetics of the Liquid-Liquid Transition in Triphenyl Phosphite.
The journal of physical chemistry. B, 2015Co-Authors: Mika Kobayashi, Ryotaro Shimizu, Hajime TanakaAbstract:There is experimental evidence suggesting the existence of a liquid–liquid transition (LLT) in a single-component liquid. However, none of this evidence is free from controversy, including the case of a molecular liquid, Triphenyl Phosphite, which we study here. Furthermore, the kinetics of LLT has been largely unexplored. Here we study the phase-transition dynamics of Triphenyl Phosphite in a supercooled liquid state by means of time-resolved polarized and depolarized small-angle light scattering to clarify whether the transition is a liquid–liquid transition (LLT) or merely nanocrystal formation. A part of this study was recently reported in another of our papers [Shimizu, R.; Kobayashi, M.; Tanaka, H. Phys. Rev. Lett. 2014, 112, 125702]. A detailed analysis of our experimental results of light scattering and the comparison with heat evolution during LLT have revealed the following facts. The polarized scattering from domains has a finite (nonzero) intensity in the low-wavenumber limit, and the time evo...
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Time-Resolved Light Scattering Study on the Kinetics of the Liquid–Liquid Transition in Triphenyl Phosphite B
The Journal of Physical Chemistry, 2015Co-Authors: Mika Kobayashi, Ryotaro Shimizu, Hajime TanakaAbstract:There is experimental evidence suggesting the existence of a liquid–liquid transition (LLT) in a single-component liquid. However, none of this evidence is free from controversy, including the case of a molecular liquid, Triphenyl Phosphite, which we study here. Furthermore, the kinetics of LLT has been largely unexplored. Here we study the phase-transition dynamics of Triphenyl Phosphite in a supercooled liquid state by means of time-resolved polarized and depolarized small-angle light scattering to clarify whether the transition is a liquid–liquid transition (LLT) or merely nanocrystal formation. A part of this study was recently reported in another of our papers [Shimizu, R.; Kobayashi, M.; Tanaka, H. Phys. Rev. Lett. 2014, 112, 125702]. A detailed analysis of our experimental results of light scattering and the comparison with heat evolution during LLT have revealed the following facts. The polarized scattering from domains has a finite (nonzero) intensity in the low-wavenumber limit, and the time evolution of its average intensity is almost proportional to the square of the heat-releasing rate. The depolarized scattering intensity monotonically increases in the process of LLT during isothermal annealing above the spinodal temperature TSD but exhibits a peak below TSD. On the basis of these results, we suggest that the primary process is LLT, whose order parameter is of a nonconserved nature, but accompanies nanocrystal formation. In the NG-type LLT, the sharp interface between liquid II droplets and the liquid I matrix promotes nanocrystal formation there, whereas much less nanocrystal formation is induced in the SD-type LLT due to the lack of such sharp interfaces.
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time resolved light scattering study on the kinetics of the liquid liquid transition in Triphenyl Phosphite b
The Journal of Physical Chemistry, 2015Co-Authors: Mika Kobayashi, Ryotaro Shimizu, Hajime TanakaAbstract:There is experimental evidence suggesting the existence of a liquid–liquid transition (LLT) in a single-component liquid. However, none of this evidence is free from controversy, including the case of a molecular liquid, Triphenyl Phosphite, which we study here. Furthermore, the kinetics of LLT has been largely unexplored. Here we study the phase-transition dynamics of Triphenyl Phosphite in a supercooled liquid state by means of time-resolved polarized and depolarized small-angle light scattering to clarify whether the transition is a liquid–liquid transition (LLT) or merely nanocrystal formation. A part of this study was recently reported in another of our papers [Shimizu, R.; Kobayashi, M.; Tanaka, H. Phys. Rev. Lett. 2014, 112, 125702]. A detailed analysis of our experimental results of light scattering and the comparison with heat evolution during LLT have revealed the following facts. The polarized scattering from domains has a finite (nonzero) intensity in the low-wavenumber limit, and the time evolution of its average intensity is almost proportional to the square of the heat-releasing rate. The depolarized scattering intensity monotonically increases in the process of LLT during isothermal annealing above the spinodal temperature TSD but exhibits a peak below TSD. On the basis of these results, we suggest that the primary process is LLT, whose order parameter is of a nonconserved nature, but accompanies nanocrystal formation. In the NG-type LLT, the sharp interface between liquid II droplets and the liquid I matrix promotes nanocrystal formation there, whereas much less nanocrystal formation is induced in the SD-type LLT due to the lack of such sharp interfaces.
Kiyoshi Takeda - One of the best experts on this subject based on the ideXlab platform.
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observation of equilibrium liquid liquid transition in Triphenyl Phosphite
Chemical Physics Letters, 2013Co-Authors: Yukio Terashima, Kiyoshi Takeda, M. Tsuchie, M. HondaAbstract:Abstract The thermal signature of an equilibrium liquid–liquid transition (LLT) in Triphenyl Phosphite was detected by differential scanning calorimetry measurements at a fast heating rate reaching 500 K min −1 . The estimated temperature, enthalpy, and entropy of the LLT were 241.7 K, 12.0 kJ mol −1 , and 49.5 J K −1 mol −1 , respectively. The estimated residual entropy for a glacial sample prepared at 224.7 K was 6 J K −1 mol −1 ; this value is much smaller than that for the normal glassy liquid. This glacial state was found to be a highly ordered liquid compared with the normal glassy liquid in terms of entropy.
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Observation of equilibrium liquid–liquid transition in Triphenyl Phosphite
Chemical Physics Letters, 2013Co-Authors: Yukio Terashima, Kiyoshi Takeda, M. Tsuchie, M. HondaAbstract:Abstract The thermal signature of an equilibrium liquid–liquid transition (LLT) in Triphenyl Phosphite was detected by differential scanning calorimetry measurements at a fast heating rate reaching 500 K min −1 . The estimated temperature, enthalpy, and entropy of the LLT were 241.7 K, 12.0 kJ mol −1 , and 49.5 J K −1 mol −1 , respectively. The estimated residual entropy for a glacial sample prepared at 224.7 K was 6 J K −1 mol −1 ; this value is much smaller than that for the normal glassy liquid. This glacial state was found to be a highly ordered liquid compared with the normal glassy liquid in terms of entropy.
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thermal study on the impurity effect on thermodynamic stability of the glacial phase in Triphenyl Phosphite Triphenyl phosphate system
Thermochimica Acta, 2005Co-Authors: Ikue Tanabe, Kiyoshi Takeda, Katsuo MurataAbstract:Abstract To investigate the impurity effect on thermodynamic stability of the glacial phase, an apparently amorphous metastable phase observed in Triphenyl Phosphite (TPP), the differential scanning calorimetry (DSC) was carried out in the temperature range 120–350 K for binary mixtures between TPP and Triphenyl phosphate (TPPO). Heating up from the glassy liquid, supercooled liquid phase transformed into glacial phase below the crystallization temperature for all the samples with x
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Thermal study on the impurity effect on thermodynamic stability of the glacial phase in Triphenyl Phosphite–Triphenyl phosphate system
Thermochimica Acta, 2005Co-Authors: Ikue Tanabe, Kiyoshi Takeda, Katsuo MurataAbstract:Abstract To investigate the impurity effect on thermodynamic stability of the glacial phase, an apparently amorphous metastable phase observed in Triphenyl Phosphite (TPP), the differential scanning calorimetry (DSC) was carried out in the temperature range 120–350 K for binary mixtures between TPP and Triphenyl phosphate (TPPO). Heating up from the glassy liquid, supercooled liquid phase transformed into glacial phase below the crystallization temperature for all the samples with x