The sorption of krypton and xenon in zeolites at high pressures and temperatures I. Chabazite

1972 ◽  
Vol 326 (1566) ◽  
pp. 315-330 ◽  
Keyword(s):  
Gas Phase ◽  
Thermodynamic Equilibrium ◽  
High Pressures ◽  
Equilibrium Constants ◽  
Standard State ◽  
Temperature Range ◽  
Thermodynamic Relationship ◽  
High Pressures And Temperatures

Isotherms of Kr and Xe in chabazite have been obtained for absolute sorption and for Gibbs excess sorption, in the temperature range 150 to 450 °C and at pressures up to 100 atm. Thermodynamic equilibrium constants for distribution of gas between the crystals and the gas phase, standard state concentrations and heats of sorption have been determined. At the highest pressures differences between absolute sorption and Gibbs excess sorption were large. The change of equilibrium fugacity with temperature for given absolute and Gibbs excess sorptions yielded two differential heats of sorption and two differential entropies of the sorbate. These heats, and the corresponding entropies, differed numerically and in their dependence upon amount sorbed. The thermodynamic relationship between the two heats has been derived and discussed.

Dimerization of Carboxylic Acids in Solution up to High Pressures and Temperatures. 2. Benzoic Acid

1987 ◽  
Vol 42 (4) ◽  
pp. 406-412 ◽  
Author(s):  
R. Barraza ◽  
E. M. Borschel ◽  
M. Buback
Keyword(s):  
Benzoic Acid ◽  
Quantitative Measurement ◽  
High Pressures ◽  
Equilibrium Constants ◽  
Cyclic Dimer ◽  
Maximum Pressure ◽  
Dilute Solution ◽  
High Pressures And Temperatures ◽  
Lower Temperature ◽  
Hydrogen Bonded

Benzoic acid in dilute solution of n-heptane and of CCl4 is studied via high-pressure hightemperature IR spectroscopy on the C = O and O - H stretching fundamentals. Lambert-Beer’s law is shown to be valid for the C = O modes of the acid monomer and of the hydrogen-bonded cyclic dimer, which enables the quantitative measurement of the dimerization equilibrium to a maximum pressure of 2 kbar and up to 175 °C. At identical pressure and temperature the dimerization equilibrium constant is larger in n-heptane than in CCl4. From the monomer-cyclic dimer equilibrium constants the pressure dependence of the dimerization enthalpy is determined and compared with direct information on both species as derived from their O - H fundamental mode absorption. Toward lower temperature the dimerization volume is decreasingly negative and, in CCl4 solution, ΔV even changes sign around 40 °C. Increasing pressure thus favours the dissociation of the hydrogen-bonded dimer into benzoic acid monomer molecules at ambient temperature.

The sorption of krypton and xenon in zeolites at high pressures and temperatures II. Comparison and analysis

1972 ◽  
Vol 326 (1566) ◽  
pp. 331-345 ◽  
Keyword(s):  
High Pressures ◽  
Equilibrium Constants ◽  
Sorption Isotherms ◽  
Rare Gas ◽  
Thermodynamic Quantities ◽  
Zeolite A ◽  
Temperature Coefficients ◽  
High Pressures And Temperatures ◽  
High Temperature High Pressure ◽  
Gas Pressures

Absolute and Gibbs excess sorption isotherms of Kr and Xe have been measured at a range of temperatures between 0 and 450 °C and at high pressures in zeolites X and Y (near-faujasites); zeolite A; H-Zeolon and Na-Zeolon (near mordenites); chabazite; and an active carbon, to compare their efficiencies in reducing the rare gas pressures in high-temperature, high-pressure systems. At 450 °C the best sorbents for the purpose were chabazite and the carbon. The isotherms have been analysed to give distribution equilibrium constants for absolute sorption and associated standard thermodynamic quantities (Δ A ⊖ , Δ E ⊖ and Δ S ⊖ ). Isosteric heats have been derived and compared as functions of amount sorbed both for absolute and for Gibbs excess uptakes. These heats differ substantially for larger uptakes, but converge as the uptake decreases. Differential entropies of the intracrystalline rare gas have been calculated for absolute sorption. They decline monotonically with amount sorbed and have temperature coefficients which appear not very different from values expected for classical oscillators.

Interaction of H2O, O2 and H2 with Proton Conducting Oxides Based on Lanthanum Scandates

2019 ◽  
pp. 88-100
Author(s):  
A. S. Farlenkov ◽  
N. A. Zhuravlev ◽  
Т. A. Denisova ◽  
М. V. Ananyev
Keyword(s):  
Water Vapor ◽  
Partial Pressure ◽  
Gas Phase ◽  
Molecular Hydrogen ◽  
Proton Magnetic Resonance ◽  
Partial Pressure Of Oxygen ◽  
Proton Conducting ◽  
Conducting Oxides ◽  
Temperature Range ◽  
Apparent Level

The research uses the method of high-temperature thermogravimetric analysis to study the processes of interaction of the gas phase in the temperature range 300–950 °C in the partial pressure ranges of oxygen 8.1–50.7 kPa, water 6.1–24.3 kPa and hydrogen 4.1 kPa with La1–xSrxScO3–α oxides (x = 0; 0.04; 0.09). In the case of an increase in the partial pressure of water vapor at a constant partial pressure of oxygen (or hydrogen) in the gas phase, the apparent level of saturation of protons is shown to increase. An increase in the apparent level of saturation of protons of the sample also occurs with an increase in the partial pressure of oxygen at a constant partial pressure of water vapor in the gas phase. The paper discusses the causes of the observed processes. The research uses the hydrogen isotope exchange method with the equilibration of the isotope composition of the gas phase to study the incorporation of hydrogen into the structure of proton-conducting oxides based on strontium-doped lanthanum scandates. The concentrations of protons and deuterons were determined in the temperature range of 300–800 °C and a hydrogen pressure of 0.2 kPa for La0.91Sr0.09ScO3–α oxide. The paper discusses the role of oxygen vacancies in the process of incorporation of protons and deuterons from the atmosphere of molecular hydrogen into the structure of the proton conducting oxides La1–xSrxScO3–α (x = 0; 0.04; 0.09). The proton magnetic resonance method was used to study the local structure in the temperature range 23–110 °C at a rotation speed of 10 kHz (MAS) for La0.96Sr0.04ScO3–α oxide after thermogravimetric measurements in an atmosphere containing water vapor, and after exposures in molecular hydrogen atmosphere. The existence of proton defects incorporated into the volume of the investigated proton oxide from both the atmosphere containing water and the atmosphere containing molecular hydrogen is unambiguously shown. The paper considers the effect of the contributions of the volume and surface of La0.96Sr0.04ScO3–α oxide on the shape of the proton magnetic resonance spectra.

Wide-range equations of state for organic liquids

2007 ◽  
Vol 5 ◽  
pp. 113-120 ◽  
Author(s):  
R.Kh. Bolotnova
Keyword(s):  
High Pressures ◽  
Equations Of State ◽  
Organic Liquids ◽  
Liquid Phases ◽  
Wide Range ◽  
High Pressures And Temperatures

The method of construction the wide-range equations of state for organic liquids, describing the gas and liquid phases including dissociation and ionization which occurs during an intense collapse of steam bubbles and accompanied by ultra-high pressures and temperatures, is proposed.

scholarly journals The thermal conductivity of the Earth's core and implications for its thermal and compositional evolution

2020 ◽  
Author(s):  
Kenji Ohta ◽  
Kei Hirose
Keyword(s):  
Thermal Conductivity ◽  
High Pressure ◽  
Thermal History ◽  
Diamond Anvil Cell ◽  
High Pressures ◽  
Iron Alloys ◽  
Compositional Evolution ◽  
The Earth ◽  
Diamond Anvil ◽  
High Pressures And Temperatures

Abstract Precise determinations of the thermal conductivity of iron alloys at high pressures and temperatures are essential for understanding the thermal history and dynamics of the metallic cores of the Earth. We review relevant high-pressure experiments using a diamond-anvil cell and discuss implications of high core conductivity for its thermal and compositional evolution.

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