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  • 1
    Electronic Resource
    Electronic Resource
    Solubility of xenon in amino-acid solutions. II. Nine less-soluble amino acids (1988)
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 88 (1988), S. 6529-6533 
    Details
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: Ostwald solubility (L) of xenon gas, as the radioisotope 133Xe, has been measured as a function of solute concentration, at 25.0 °C, in aqueous solutions of nine amino acids. The amino-acid concentrations investigated covered much of their solubility ranges in water, viz., asparagine monohydrate (0–0.19 M), cysteine (0–1.16 M), glutamine (0–0.22 M), histidine (0–0.26 M), isoleucine (0–0.19 M), methionine (0–0.22 M), serine (0–0.38 M), threonine (0–1.4 M), and valine (0–0.34 M). We have previously reported solubility results for aqueous solutions of six other, generally more soluble, amino acids (alanine, arginine, glycine, hydroxyproline, lysine, and proline), of sucrose and sodium chloride. In general, L decreases approximately linearly with increasing solute concentration in these solutions. If we postulate that the observed decreases in gas solubility are due to hydration, the results under some assumptions can be used to calculate hydration numbers (H), i.e., the number of H2O molecules associated with each amino-acid solute molecule. The average values of hydration number (H¯) obtained at 25.0 °C are 15.3±1.5 for asparagine, 6.8±0.3 for cysteine, 11.5±1.1 for glutamine, 7.3±0.7 for histidine, 5.9±0.4 for isoleucine, 10.6±0.8 for methionine, 11.2±1.3 for serine, 7.7± 1.0 for threonine, and 6.6±0.6 for valine. We have also measured the temperature dependence of solubility L(T) from 5–40 °C for arginine, glycine, and proline, and obtained hydration numbers H¯(T) in this range. Between 25–40 °C, arginine has an H¯ near zero. This may be evidence for an attractive interaction between xenon and arginine molecules in aqueous solution.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.454438
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  • 2
    Electronic Resource
    Electronic Resource
    Solubility of xenon in amino-acid solutions (1986)
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 85 (1986), S. 456-461 
    Details
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: We have measured the Ostwald solubility (L) of 133Xe at 25.0 °C in aqueous solutions of the amino acids: alanine (0–1.8 M), arginine (0–0.9 M), glycine (0–2.1 M), hydroxyproline (0–2.3 M), lysine (0–2.8 M), and proline (0–3.5 M) as well as sucrose (0–2.25 M) and NaCl (0–5.25 M). Over the concentration ranges investigated L decreases, monotonically and approximately linearly, with increasing concentration for amino acids and sucrose. The effect on gas solubility of amino acid in solution can be large, e.g., for 133Xe, we measured L(25.0 °C)=0.1060 in distilled water but L(25.0 °C)=0.055 for a 2.8 M lysine solution. The results can be used to calculate hydration numbers (H), i.e., the number of H2O molecules associated with each solute molecule. The average values of hydration number (H¯) obtained at 25.0 °C are 7.9±0.6 for alanine, 0.2±0.5 for arginine, 8.5±0.6 for glycine, 4.5±0.4 for hydroxyproline, 6.1±1.1 for lysine, 2.0±0.2 for proline, and 3.9±0.7 for sucrose.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.451623
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  • 3
    Electronic Resource
    Electronic Resource
    Diffusion of xenon in liquid alkanes: Temperature dependence measurements with a new method. Stokes–Einstein and hard sphere theories (1990)
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 92 (1990), S. 625-630 
    Details
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: Measurements are reported of the diffusion constant D(T) for xenon gas, in the form of the radioisotope 133Xe, through liquid n-octane, n-decane, and n-tetradecane, in the range 10–40 °C. The values range from D (10.0 °C, Xe→n-C14H30)=1.32×10−5 cm2/s to D (40.0 °C, Xe→n-C8H18)=6.02×10−5 cm2/s. A new experimental method is used in which D is obtained by monitoring the decrease in concentration as gas diffuses into the liquid in an effectively one-dimensional geometry. As expected, the results do not agree with the Stokes–Einstein law. They do follow the usual correlation Dηp=AT, with p=0.708 and A=9.80×10−8, where η is the liquid viscosity in centipoises and T is in K. Application to these results of the rough-hard-sphere theory of diffusion is discussed. A quantitative analysis cannot be made until molecular dynamics results for smooth-hard-sphere diffusion are available.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.458413
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    Paper (German National Licenses)
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  • 4
    Electronic Resource
    Electronic Resource
    Solubility of xenon in 45 organic solvents including cycloalkanes, acids, and alkanals: Experiment and theory (1989)
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 90 (1989), S. 6569-6579 
    Details
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: New measurements are reported of the Ostwald solubility L(T), as a function of temperature in the approximate range 10.0–50.0 °C, for 133Xe gas in 13 liquid organic solvents, viz., three cycloalkanes, six carboxylic acids, and four normal alkanals. From our data for each solute–solvent system we determine the mole-fraction solubility x2(T), and the following thermodynamic functions of solution: chemical potential Δμ0ρ2(T)=−RT ln L, enthalpy ΔH¯0ρ2, and entropy ΔS¯0ρ2, where Δμ0ρ2=ΔH¯0ρ2 −TΔS¯0ρ2S¯0ρ2, all based on the number density scale. New results are considered together with previous measurements of xenon solubility in liquid normal alkanes, alkanols, and perfluoroalkanes; in all, data and theory are treated for xenon solubility in 45 organic solvents from six homologous series. The average observed entropy of solvation of Xe is ΔS¯0ρ2=−4.1± 0.5 cal/mol K, remarkably independent of solvent. The results are analyzed with scaled-particle theory from which are obtained hard-core diameters a1, and cavity energies gcav and enthalpies hcav for all the solvents at 25 °C. Values of a1 range from 4.08 A(ring) (for CH3OH) to 9.18 A(ring) (n-C20H42), and gcav ranges from 2520 cal/mol (n-C6F14) to 9430 cal/mol (HCOOH). We discuss the application to solubility in these solvents of interaction site calculations; interaction potentials for the functional groups are available but difficult to apply to these solute–solvent systems. We also discuss the role of configurational entropy, as well as molecular dynamics approaches to calculation of free energies of solubility. Finally the results are examined empirically and values are given for the contribution to chemical potential, enthalpy, and entropy of solvation, of the six functional groups: CH2 (linear molecules), CH3, OH, COOH, CHO, and CH2 (cyclomolecules).
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.456324
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    Paper (German National Licenses)
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