The Experts below are selected from a list of 273 Experts worldwide ranked by ideXlab platform
N. N. Smirnova - One of the best experts on this subject based on the ideXlab platform.
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Thermodynamics of tetraphenylantimony benzoate Ph4SbOC(O)Ph
The Journal of Chemical Thermodynamics, 2019Co-Authors: D. V. Lyakaev, N. N. Smirnova, Alexey V. Markin, Vladimir V. Sharutin, Olga K. SharutinaAbstract:Abstract In the present research, the temperature dependence of the heat capacity C p , m o = f(T) of tetraphenylantimony benzoate Ph4SbOC(O)Ph has been measured in the range T = (5 and 480) K in the precision adiabatic vacuum and differential scanning calorimeters and reported for the first time. In the studied temperature region the melting of the compound has been revealed and its standard thermodynamic characteristics were analyzed. The standard thermodynamic functions (p° = 0.1 MPa) of Ph4SbOC(O)Ph in crystalline and liquid states were calculated with the obtained experimental data: C p , m o / R , Δ 0 T H m o / R T , Δ 0 T S m o /R and Φ m o = Δ 0 T S m o – Δ 0 T H m o /T (where R is the Universal Gas Constant) from T → 0 to 480 K. The energy of combustion of Ph4SbOC(O)Ph was measured. The standard enthalpy of combustion, formation enthalpy, formation entropy, Gibbs energy of formation of the substance in the crystalline state at T = 298.15 K were calculated. Comparison of thermodynamic properties was made for the derivatives of antimony studied in the present work, Ph5Sb and other of type Ph3SbX2.
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Thermodynamic properties of triphenylantimony dipropionate Ph3Sb(OC(O)C2H5)2 over the range from T → 0 to 430 K
The Journal of Chemical Thermodynamics, 2017Co-Authors: Alexey V. Markin, N. N. Smirnova, Vladimir V. Sharutin, D. V. Lyakaev, Olga K. SharutinaAbstract:Abstract In the present research, the temperature dependence of heat capacity C p,m o = f ( T ) of crystalline triphenylantimony dipropionate Ph 3 Sb(OC(O)C 2 H 5 ) 2 has been measured between T = (5 and 430) K in the precision adiabatic vacuum and differential scanning calorimeters and reported for the first time. In the studied temperature region the melting of the compound has been identified and its standard thermodynamic characteristics were analyzed. The standard thermodynamic functions ( p ° = 0.1 MPa) of Ph 3 Sb(OC(O)C 2 H 5 ) 2 in crystalline and liquid states were calculated with the obtained experimental data: C p,m o / R , Δ 0 T H m o / RT , Δ 0 T S m o / R and Φ m o = Δ 0 T S m o - Δ 0 T H m o / T (where R is the Universal Gas Constant) from T → 0 to 430 K. The standard entropy of formation of compound in the crystalline state was determined at T = 298.15 K. Also isochoric heat capacity was calculated as its atomic and lattice contributions were estimated.
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Thermodynamic properties of α-terpineol over the range from T → (0 to 345) K
Journal of Thermal Analysis and Calorimetry, 2015Co-Authors: Alexey V. Markin, N. N. Smirnova, I. S. Il’ichev, T. I. Dolinsky, A. B. RadbilAbstract:In the present research, the temperature dependence of heat capacity \( C_{{\text{p}\text{,m}}}^{\text{o}} = f\left( T \right) \) of α-terpineol has been measured for the first time between T = (6 and 345) K in the precision adiabatic vacuum calorimeter. The temperature and enthalpy of fusion of α-terpineol and the total mole fraction of impurities have been determined. The experimental results have been used to calculate the standard thermodynamic functions \( C_{{\text {p}\text{,m}}}^{\text{o}} /R,\;\Delta_{\text{0}}^{\text {T}} H_{\text{m}}^{\text{o}} /RT,\Delta_{\text{0}}^{\text {T}} S_{\text{m}}^{\text{o}} /R\;{\text{and}}\;\Phi_{\text{m}}^{\text{o}} /R = \Delta_{\text{0}}^{\text T} S_{\text{m}}^{\text{o}} /R{-}\Delta_{\text{0}}^{\text T} H_{\text{m}}^{\text{o}} /RT \) (where R is the Universal Gas Constant) of α-terpineol over the range from T → (0 to 345) K. The standard entropy of formation of the compound (cr) under study at T = 298.15 K has been calculated.
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Thermodynamic properties of neopentylbenzene over the range from T → (0 to 350) K
The Journal of Chemical Thermodynamics, 2012Co-Authors: N. N. Smirnova, I.a. Letyanina, Yu.a. Zakharova, A.a. Pimerzin, E.e. VishnevskayaAbstract:Abstract In the present research, the temperature dependence of heat capacity C p ,m ∘ = f ( T ) of neopentylbenzene C6H5–C5H11 has been measured between T = (6 and 350) K in the precision adiabatic vacuum calorimeter and reported for the first time. The temperature and enthalpy of fusion of neopentylbenzene and the total mole fraction of impurities have been determined. The experimental results have been used to calculate the standard (р° = 0.1 MPa) thermodynamic functions C p ,m ∘ / R , Δ 0 T H m ∘ / RT , Δ 0 T S m ∘ / R and Φ m ∘ / R = Δ 0 T S m ∘ / R - Δ 0 T H m ∘ / RT (where R is the Universal Gas Constant) of neopentylbenzene over the range from T → (0 to 350) K. The standard entropy of formation of the compound under study at T = 298.15 K has been calculated.
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Thermodynamic properties of pentaphenylantimony Ph5Sb over the range from T → 0 K to 400 K
The Journal of Chemical Thermodynamics, 2009Co-Authors: N. N. Smirnova, Alexey V. Markin, I.a. Letyanina, V. N. Larina, Vladimir V. Sharutin, V.s. SenchurinAbstract:Abstract In the present research, the temperature dependence of the heat capacity C p ,m ∘ = f ( T ) of pentaphenylantimony Ph5Sb has been measured between T = (6 and 350) K in the precision adiabatic vacuum calorimeter and from T = (327 to 415) K in the differential scanning calorimeter and reported for the first time. The melting of the sample has been observed within the above temperature range. The melting was accompanied by partial compound decomposition. The experimental results have been used to calculate the standard (p∘ = 0.1 MPa) thermodynamic functions C p ,m ∘ / R , Δ 0 T H m ∘ / RT , Δ 0 T S m ∘ / R , and Φ m ∘ / R = Δ 0 T S m ∘ / R - Δ 0 T H m ∘ / RT (where R is the Universal Gas Constant) of crystalline Ph5Sb over the range from T → 0 K to 400 K. The energy of combustion of the compound under study has been determined in the isothermal combustion calorimeter with a stationary bomb. The standard thermodynamic functions of crystalline Ph5Sb formation at T = 298.15 K have been calculated.
Michael R. Moldover - One of the best experts on this subject based on the ideXlab platform.
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Measurement of the Universal Gas Constant R Using a Spherical Acoustic Resonator
2018Co-Authors: Michael R. Moldover, J.p.m. Trusler, T. J. Edwards, James B. Mehl, R. S. DavisAbstract:• The uncer tainty in the new value is 1.7 ppm (stan dard error), a factor of 5 smaller than the uncertainty in the best previous value. The Gas Constant was determined from measurements of the speed of sound in argon as a function of pressure at the temperature of the triple point of water. The speed of sound was mea sured with a spherical resonator whose volume was determined by weighing the mercury required to fill it at the temperature of the tri~le point. The molar mass of the argon was determined by comparing the speed of sound in it to the speed of sound in a standard sample of argon of accurately known chemical and isotoptic composition.
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optimizing acoustic measurements of the boltzmann Constant
Comptes Rendus Physique, 2009Co-Authors: Michael R. MoldoverAbstract:Abstract We review the progress in acoustic metrology of Gases that has occurred since the 1988 measurement of the Universal Gas Constant R using a spherical acoustic resonator. The advances in understanding resonators and in calculating the thermophysical properties of helium ab initio suggest that today one could determine Boltzmann's Constant k B from acoustic measurements using either helium or argon with a relative uncertainty less than 10−6. To cite this article: M.R. Moldover, C. R. Physique 10 (2009).
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Acoustic resonators for measuring the thermodynamic and transport properties of industrial Gases and for calibrating thermometers
The Journal of the Acoustical Society of America, 2001Co-Authors: Michael R. MoldoverAbstract:At the NIST, high Q cylindrical acoustic resonators are routinely used to measure the speed of sound in difficult‐to‐handle process Gases with uncertainties of 0.01% or less. Model intermolecular potentials are fitted to the acoustic data to obtain the Gas density and heat capacities with uncertainties of 0.1% as well as estimates of the viscosity and thermal conductivity. We have developed novel, low‐Q, acoustic resonators to directly measure the viscosity and thermal conductivity. Spherical resonators are used to measure the speed of sound in Gases with sub‐part‐per‐million uncertainties. An argon‐filled spherical resonator was used to redetermine the Universal Gas Constant R with a fractional standard uncertainty of 1.7×10−6. The same resonator was used to measure imperfections of the internationally accepted temperature scale (ITS90) in the range 217–303 K with uncertainties of 0.6 mK; this work is now being extended to 800 K. In effect, very accurate speed‐of‐sound measurements will be used to calibrate other thermometers.
Alexey V. Markin - One of the best experts on this subject based on the ideXlab platform.
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Thermodynamics of tetraphenylantimony benzoate Ph4SbOC(O)Ph
The Journal of Chemical Thermodynamics, 2019Co-Authors: D. V. Lyakaev, N. N. Smirnova, Alexey V. Markin, Vladimir V. Sharutin, Olga K. SharutinaAbstract:Abstract In the present research, the temperature dependence of the heat capacity C p , m o = f(T) of tetraphenylantimony benzoate Ph4SbOC(O)Ph has been measured in the range T = (5 and 480) K in the precision adiabatic vacuum and differential scanning calorimeters and reported for the first time. In the studied temperature region the melting of the compound has been revealed and its standard thermodynamic characteristics were analyzed. The standard thermodynamic functions (p° = 0.1 MPa) of Ph4SbOC(O)Ph in crystalline and liquid states were calculated with the obtained experimental data: C p , m o / R , Δ 0 T H m o / R T , Δ 0 T S m o /R and Φ m o = Δ 0 T S m o – Δ 0 T H m o /T (where R is the Universal Gas Constant) from T → 0 to 480 K. The energy of combustion of Ph4SbOC(O)Ph was measured. The standard enthalpy of combustion, formation enthalpy, formation entropy, Gibbs energy of formation of the substance in the crystalline state at T = 298.15 K were calculated. Comparison of thermodynamic properties was made for the derivatives of antimony studied in the present work, Ph5Sb and other of type Ph3SbX2.
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Thermodynamic properties of triphenylantimony dipropionate Ph3Sb(OC(O)C2H5)2 over the range from T → 0 to 430 K
The Journal of Chemical Thermodynamics, 2017Co-Authors: Alexey V. Markin, N. N. Smirnova, Vladimir V. Sharutin, D. V. Lyakaev, Olga K. SharutinaAbstract:Abstract In the present research, the temperature dependence of heat capacity C p,m o = f ( T ) of crystalline triphenylantimony dipropionate Ph 3 Sb(OC(O)C 2 H 5 ) 2 has been measured between T = (5 and 430) K in the precision adiabatic vacuum and differential scanning calorimeters and reported for the first time. In the studied temperature region the melting of the compound has been identified and its standard thermodynamic characteristics were analyzed. The standard thermodynamic functions ( p ° = 0.1 MPa) of Ph 3 Sb(OC(O)C 2 H 5 ) 2 in crystalline and liquid states were calculated with the obtained experimental data: C p,m o / R , Δ 0 T H m o / RT , Δ 0 T S m o / R and Φ m o = Δ 0 T S m o - Δ 0 T H m o / T (where R is the Universal Gas Constant) from T → 0 to 430 K. The standard entropy of formation of compound in the crystalline state was determined at T = 298.15 K. Also isochoric heat capacity was calculated as its atomic and lattice contributions were estimated.
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Thermodynamic properties of α-terpineol over the range from T → (0 to 345) K
Journal of Thermal Analysis and Calorimetry, 2015Co-Authors: Alexey V. Markin, N. N. Smirnova, I. S. Il’ichev, T. I. Dolinsky, A. B. RadbilAbstract:In the present research, the temperature dependence of heat capacity \( C_{{\text{p}\text{,m}}}^{\text{o}} = f\left( T \right) \) of α-terpineol has been measured for the first time between T = (6 and 345) K in the precision adiabatic vacuum calorimeter. The temperature and enthalpy of fusion of α-terpineol and the total mole fraction of impurities have been determined. The experimental results have been used to calculate the standard thermodynamic functions \( C_{{\text {p}\text{,m}}}^{\text{o}} /R,\;\Delta_{\text{0}}^{\text {T}} H_{\text{m}}^{\text{o}} /RT,\Delta_{\text{0}}^{\text {T}} S_{\text{m}}^{\text{o}} /R\;{\text{and}}\;\Phi_{\text{m}}^{\text{o}} /R = \Delta_{\text{0}}^{\text T} S_{\text{m}}^{\text{o}} /R{-}\Delta_{\text{0}}^{\text T} H_{\text{m}}^{\text{o}} /RT \) (where R is the Universal Gas Constant) of α-terpineol over the range from T → (0 to 345) K. The standard entropy of formation of the compound (cr) under study at T = 298.15 K has been calculated.
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Thermodynamic properties of pentaphenylantimony Ph5Sb over the range from T → 0 K to 400 K
The Journal of Chemical Thermodynamics, 2009Co-Authors: N. N. Smirnova, Alexey V. Markin, I.a. Letyanina, V. N. Larina, Vladimir V. Sharutin, V.s. SenchurinAbstract:Abstract In the present research, the temperature dependence of the heat capacity C p ,m ∘ = f ( T ) of pentaphenylantimony Ph5Sb has been measured between T = (6 and 350) K in the precision adiabatic vacuum calorimeter and from T = (327 to 415) K in the differential scanning calorimeter and reported for the first time. The melting of the sample has been observed within the above temperature range. The melting was accompanied by partial compound decomposition. The experimental results have been used to calculate the standard (p∘ = 0.1 MPa) thermodynamic functions C p ,m ∘ / R , Δ 0 T H m ∘ / RT , Δ 0 T S m ∘ / R , and Φ m ∘ / R = Δ 0 T S m ∘ / R - Δ 0 T H m ∘ / RT (where R is the Universal Gas Constant) of crystalline Ph5Sb over the range from T → 0 K to 400 K. The energy of combustion of the compound under study has been determined in the isothermal combustion calorimeter with a stationary bomb. The standard thermodynamic functions of crystalline Ph5Sb formation at T = 298.15 K have been calculated.
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Thermodynamics of bis-(η6-diphenyl)chromium (I) fulleride [(η6-Ph2)2Cr]+[C60]− in the range from T → (0 to 360) K
The Journal of Chemical Thermodynamics, 2006Co-Authors: N. N. Smirnova, T.a. Bykova, Alexey V. Markin, I. E. Boronina, G. A. Domrachev, Yu. A. Shevelev, G. V. MarkinAbstract:Abstract In the present work, the temperature dependence of heat capacity C p , m ∘ = f ( T ) of crystalline bis-(η6-diphenyl)chromium (I) fulleride [(η6-Ph2)2Cr]+[C60] − has been measured by precision adiabatic vacuum calorimetry between T = (6 and 360) K with an uncertainty of ±0.2%. In this temperature interval, the transformations were detected and their thermodynamic characteristics were estimated. The experimental data were used for calculating standard (po = 0.1 MPa) thermodynamic functions C p , m ∘ / R , Δ 0 T H m ∘ / RT , Δ 0 T S m ∘ / R and Φ m ∘ / R = Δ 0 T S m ∘ / R - Δ 0 T H m ∘ / RT (where R is the Universal Gas Constant) in the range T → (0 to 360) K.
William E. Acree - One of the best experts on this subject based on the ideXlab platform.
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Comment on “Solubility determination and correlation of cyromazine in sixteen pure solvents and mixing properties of solutions”
Fluid Phase Equilibria, 2019Co-Authors: William E. AcreeAbstract:Abstract The numerical values of the logarithm of the infinite dilution activity coefficient, ln γ 1 ∞ , and excess partial molar excess enthalpy at infinite dilution, H 1 E , ∞ , calculated by Zhang and coworkers are not thermodynamically consistent with each other. The calculated values do not obey the standard thermodynamic relationship that the variation in ln γ 1 ∞ with 1/T must be equal H 1 E , ∞ divided by the Universal Gas Constant.
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Comments on the “Determination and correlation of the solubility and thermodynamic parameters of 2,3,5,4′-tetrahydroxystilbene-2-O-β-d-glucoside in pure organic solvents”
Journal of Molecular Liquids, 2018Co-Authors: William E. AcreeAbstract:Abstract Errors are discovered in the authors' calculated excess enthalpies based on the Buchowski-Ksiazcyak λh equation. The authors inadvertently subtracted the solute's enthalpy of fusion from the product Universal Gas Constant (in Joules/(mole K)) times Buchowski-Ksiazcyak h parameter, without changing the units of solute's enthalpy of fusion to Joules/mole. As a result all of the 81 excess enthalpies given in Table 8 of the published paper by Huang and coworkers are in error.
Thomas Malcherek - One of the best experts on this subject based on the ideXlab platform.
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Structure and phase transitions of LiTaOGeO4
Acta Crystallographica Section B Structural Science, 2002Co-Authors: Thomas MalcherekAbstract:The structure of LiTaOGeO4 has been refined using X-ray diffraction data collected at 293 K and at 173 K. The low-temperature structure is isostructural with LiTaOSiO4 and closely related to the low-temperature structure of titanite, CaTiOSiO4. Li occurs in a distorted tetrahedral coordination. The transition to the disordered structure, with space group symmetry C2/c, occurs at Tc = 231 (1) K. Li is disordered across two symmetry-equivalent positions and Ta is located at the centre of its coordination octahedron in this paraphase. The transition is continuous, and the thermal evolution of the order parameter is well approximated using a tricritical mean-field model. Anharmonic thermal displacement of the Li cation has been analyzed and its one-particle potential has been determined. The height of the potential barrier separating the two Li positions across a curved trajectory is close to RTc, where R is the Universal Gas Constant.
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Structure and phase transitions of LiTaOGeO(4).
Acta crystallographica. Section B Structural science, 2002Co-Authors: Thomas MalcherekAbstract:The structure of LiTaOGeO(4) has been refined using X-ray diffraction data collected at 293 K and at 173 K. The low-temperature structure is isostructural with LiTaOSiO(4) and closely related to the low-temperature structure of titanite, CaTiOSiO(4). Li occurs in a distorted tetrahedral coordination. The transition to the disordered structure, with space group symmetry C2/c, occurs at T(c) = 231 (1) K. Li is disordered across two symmetry-equivalent positions and Ta is located at the centre of its coordination octahedron in this paraphase. The transition is continuous, and the thermal evolution of the order parameter is well approximated using a tricritical mean-field model. Anharmonic thermal displacement of the Li cation has been analyzed and its one-particle potential has been determined. The height of the potential barrier separating the two Li positions across a curved trajectory is close to RT(c), where R is the Universal Gas Constant.
