Sorption of the Inert Gases (Ar, Kr, and Xe) in Type A Zeolites

1975 ◽  
Vol 53 (7) ◽  
pp. 996-1006 ◽  
Author(s):  
Russell Ian Derrah ◽  
Douglas Morris Ruthven
Keyword(s):  
Low Temperatures ◽  
Equilibrium Constants ◽  
Type A ◽  
Inert Gases ◽  
Henry's Law ◽  
Equilibrium Isotherms ◽  
Adsorbed Phase ◽  
5A Zeolite ◽  
Experimental Values ◽  
Henry Constants

Theoretical potential profiles for Ar, Kr, and Xe occluded in an idealized 5A zeolite are calculated and used to evaluate the Henry's law equilibrium constants for these species. Calculations were made using the three common formulae to estimate the dispersion constants (Kirkwood–Mueller, Slater–Kirkwood, and London) and the theoretical Henry constants are compared with the values obtained directly from experimental equilibrium isotherms. For both Kr and Xe the Slater–Kirkwood formula gives the best agreement with the experimental values while, for argon, the London formula is best. At higher concentrations the isotherms for Kr can be well represented by a simple Langmuir expression with eleven sites per cavity while for Xe there appears to be a transition from localized sorption at low temperatures to a mobile adsorbed phase at higher temperatures. These conclusions are qualitatively consistent with the results of the theoretical potential calculations.

Some phase relationships between basic bismuth chlorides in aqueous solutions at 25 °C

1987 ◽  
Vol 65 (12) ◽  
pp. 2824-2829 ◽  
Author(s):  
Peter Taylor ◽  
Vincent J. Lopata
Keyword(s):  
Aqueous Solutions ◽  
Equilibrium Constants ◽  
Natural Occurrence ◽  
Chloride Solutions ◽  
Gibbs Energies ◽  
Activity Ratios ◽  
Aqueous Chloride ◽  
The Stability ◽  
Experimental Values ◽  
Phase Relationships

Observations are reported on the interconversion of solid α-Bi2O3, Bi12O17Cl2, BiOCl, and a daubréeite-like phase tentatively identified as Bi2O2(OH)Cl, in aqueous chloride solutions at 25 °C. Equilibrium constants, K, for these interconversions are expressed as anion activity ratios, {Cl−}/{OH−}. Experimental values of K for equilibrium between Bi2O3 and each of the chlorides are 100.56 ± 0.20 for Bi12O17Cl2, 101.5 ± 0.4 for Bi2O2(OH)Cl, and 103.13 ± 0.04 for BiOCl; the fatter two represent metastable equilibria. These equilibrium constants yielded the following estimates of Gibbs energies of formation: Bi12O17Cl2, −3141 ± 6 kJ mol−1;"Bi2O2(OH)Cl", −696 ± 4 kJ mol−1; BiOCl, −321.5 ± 1.3 kJ mol−1. Phase relationships among these solids are discussed, with reference to natural occurrence, other bismuth oxychlorides, and the stability of other basic salts of bismuth.

scholarly journals Molecular Dynamics Calculation of the Thermodynamic Properties of Methane

1975 ◽  
Vol 28 (3) ◽  
pp. 315 ◽  
Author(s):  
HJM Hanley ◽  
RO Watts
Keyword(s):  
Molecular Dynamics ◽  
Thermodynamic Properties ◽  
Specific Heat ◽  
Low Temperatures ◽  
Spherically Symmetric ◽  
Method Of Molecular Dynamics ◽  
Experimental Values ◽  
Dynamics Calculation ◽  
Liquid States ◽  
Three Body

Thermodynamic properties of methane in the dense gas and liquid states have been calculated by the method of molecular dynamics. The methane pair interactions were modelled using a spherically symmetric m-6-8 potential, and the most significant three-body and quantum effects were included. Agreement between calculated and experimental values for the energy and pressure is generally good except at low temperatures and high densities. The specific heat at constant volume is also briefly discussed.

scholarly journals Studies on gas-solid equilibria VI- Adsorption from binary gas mixtures by silica gel

1936 ◽  
Vol 153 (880) ◽  
pp. 584-600 ◽  
Keyword(s):  
Gaseous Phase ◽  
Total Pressure ◽  
Gas Mixtures ◽  
High Accuracy ◽  
Reliable Data ◽  
Adsorption System ◽  
Solid Adsorbent ◽  
Adsorbed Phase ◽  
Pressure Concentration ◽  
Experimental Values

In Part V of this work, an experimental method was described for the study of pressure-concentration equilibria between adsorbent solids and binary gas mixtures. This technique has made it possible to obtain experimental values of high accuracy and reliability for ( a ) gas volumes admitted to an adsorption system (which is maintained at a constant temperature); ( b ) the total volume and the total pressure of the gaseous phase within the system at equilibrium; ( c ) the total volume of gas adsorbed by the solid adsorbent; ( d ) the exact composition of the gaseous phase at equilibrium. The amount of each gas in the adsorbed phase and the partial pressure of each gas in the gaseous phase can therefore be determined with certainty; and reliable data can consequently be obtained for the examination of the problem of adsorption from binary gas mixtures by adsorbent solids.

Ultrarot-Intensitäten von Acetylenen des Typs (CH3)3X - C ≡ C - Y

1970 ◽  
Vol 25 (4) ◽  
pp. 572-574 ◽  
Author(s):  
V. Hoffmann ◽  
G. Stehlik ◽  
W. Zeil
Keyword(s):  
Type A ◽  
Normal Coordinates ◽  
Infrared Intensities ◽  
Stretching Vibrations ◽  
The Absolute ◽  
Experimental Values

AbstractThe absolute integrated infrared intensities of the C ≡ C- and the ≡ C - H-stretching vibrations of four acetylenes of the type (CH3)3X-C≡C-Y (X = C, Si and Y = H, D) are reported. The obtained values are discussed with respect to the eigenvectors of the normal coordinates of these vibrations and with respect to coupling between these two vibrations and also between these and other vibrations of the type A1 . An attempt is made to involve the experimental values in an assumed (p-d) π-interaction.

scholarly journals Technical note: Estimating aqueous solubilities and activity coefficients of mono- and <i>α</i>,<i>ω</i>-dicarboxylic acids using COSMO<i>therm</i>

2020 ◽  
Vol 20 (21) ◽  
pp. 13131-13143
Author(s):  
Noora Hyttinen ◽  
Reyhaneh Heshmatnezhad ◽  
Jonas Elm ◽  
Theo Kurtén ◽  
Nønne L. Prisle
Keyword(s):  
Activity Coefficients ◽  
Equilibrium Constants ◽  
Hydrate Formation ◽  
Dicarboxylic Acids ◽  
Aqueous Solubility ◽  
Technical Note ◽  
Acid Water ◽  
Monocarboxylic Acids ◽  
Wide Range ◽  
Experimental Values

Abstract. We have used the COSMOtherm program to estimate activity coefficients and solubilities of mono- and α,ω-dicarboxylic acids and water in binary acid–water systems. The deviation from ideality was found to be larger in the systems containing larger acids than in the systems containing smaller acids. COnductor-like Screening MOdel for Real Solvents (COSMO-RS) underestimates experimental monocarboxylic acid activity coefficients by less than a factor of 2, but experimental water activity coefficients are underestimated more especially at high acid mole fractions. We found a better agreement between COSMOtherm-estimated and experimental activity coefficients of monocarboxylic acids when the water clustering with a carboxylic acid and itself was taken into account using the dimerization, aggregation, and reaction extension (COSMO-RS-DARE) of COSMOtherm. COSMO-RS-DARE is not fully predictive, but fit parameters found here for water–water and acid–water clustering interactions can be used to estimate thermodynamic properties of monocarboxylic acids in other aqueous solvents, such as salt solutions. For the dicarboxylic acids, COSMO-RS is sufficient for predicting aqueous solubility and activity coefficients, and no fitting to experimental values is needed. This is highly beneficial for applications to atmospheric systems, as these data are typically not available for a wide range of mixing states realized in the atmosphere, due to a lack of either feasibility of the experiments or sample availability. Based on effective equilibrium constants of different clustering reactions in the binary solutions, acid dimer formation is more dominant in systems containing larger dicarboxylic acids (C5–C8), while for monocarboxylic acids (C1–C6) and smaller dicarboxylic acids (C2–C4), hydrate formation is more favorable, especially in dilute solutions.

scholarly journals NOBLE GAS SOLUBILITY IN SUPER-CRITICAL WATER: IMPLICATIONS FOR INERT GAS STUDIES AND GEOCHRONOLOGY

1984 ◽  
Vol 23 (4) ◽  
pp. 483-490
Author(s):  
J. G. Mitchell ◽  
D. J. Terrell
Keyword(s):  
Low Temperatures ◽  
Volume Diffusion ◽  
Noble Gas ◽  
Inert Gases ◽  
Inert Gas ◽  
Gas Solubility ◽  
Transport Medium

Inert gases will ideally exhibit infinite miscibility with super-critical water.  The implications of this phenomenon are discussed in the context of the resetting of the K-Ar system during regional metamorhism, and emplacement of granites.  Inert gas abundances in oceanfloor rocks and shales may also be interpreted as a consequence (at least in part) of partioning between water and silicate phases in which the light inert gases are preferentially taken up in water.  The funtion of super-critical water as a transport medium for inert gases offers an important alternative to the unlikely process of volume diffusion at low temperatures.

The use of electron gas modification in the evaluation of the vibration frequencies and the specific heats of sodium and potassium

1961 ◽  
Vol 262 (1308) ◽  
pp. 136-144 ◽  
Keyword(s):  
Low Temperatures ◽  
Electron Gas ◽  
Outer Region ◽  
Low Density ◽  
Vibration Frequencies ◽  
Specific Heats ◽  
A New Technique ◽  
Experimental Values ◽  
Sodium And Potassium

The earlier work on the determination of the specific heats of lithium by the use of deLaunay’s model has been extended to sodium and potassium. A new technique has been introduced in which the contributions of the central and the outer parts of the Brillouin zone to C v are calculated separately from different distribution densities of 8000 and 1000 points per zone, respectively. The agreement between the calculated and the experimental values of C v has been found to be very good except at very low temperatures where the deviations can be ascribed to the presence of phase transformation. The effect of using a finer mesh of points on C v has been examined. In order to get accurate values of C v the density of points in the central region has to be increased considerably. In the outer region, however, a low density of eight points per zone as in Raman’s theory is found to be reasonably satisfactory.

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