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  • 1
    ISSN: 1612-1112
    Keywords: Gas-solid chromatography ; Graphitized thermal carbon black ; Thermodynamics of adsorption ; Nitrogen compounds
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary To study the role of the nitrogen atom in various valence states in the adsorption of nitrogen-containing molecules on the surface of hydrogen-treated graphitized thermal carbon black (HGTCB) gas chromatography was applied to determine the thermodynamic characteristics of adsorption: Henry's constants and heats of adsorption at zero surface coverage of nitriles, amines and indols on HGTCB. Adsorption characteristics of nitrogen-containing organic compounds and corresponding hydrocarbons are compared. It is shown that the logarithm of the retention volume and the heat of adsorption of n-alkylamines and n-alkylnitriles linearly depend on the number of carbon atoms in the molecule and on the average polarisability of the molecule. Relationship has been established between the Henry's constant as well as the heat of adsorption and the geometry of the molecule's disposition on HGTCB surface. Examples are given for the separation of a number of amines on the basis of the geometry of their molecules.
    Type of Medium: Electronic Resource
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  • 2
    ISSN: 1612-1112
    Keywords: Gas-solid chromatography ; Graphitized carbon black ; Aromatic hydrocarbons
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary This paper defines values of retention volumes for zero surface coverage (Henry's constant) at different temperatures, retention indices and variations of the internal energy (differential heats of adsorption) of diphenyl and its alkyl derivatives, terphenyls, diphenylmethane, triphenylmethane, diphenylethanes and fluorene on graphitized thermal carbon black (GTCB). Adsorption on GTCB takes place in accordance with the geometry of these molecules, the strongest adsorption being observed for para-terphenyl with least inhibited internal rotation of the molecule, while the weakest adsorption occurs for 2,6,2′,6′-tetramethyldiphenyl with the most inhibited internal rotation of the molecules. The flat molecules of fluorene are adsorbed on GTCB more readily than the nonflat molecules of diphenylmethane.
    Type of Medium: Electronic Resource
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  • 3
    ISSN: 1612-1112
    Keywords: Gas Chromatography-Mass Spectrometry ; Isomers of perhydroanthracene and perhydrophenanthrene ; Low energy mass spectra ; Graphitized carbon black
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary A gas chromatographic-mass spectrometric study of a mixture of the stereoisomers of perhydroanthracene (PHA) and perhydrophenanthrene (PHP) has been carried out. Separation was accomplished on capillary columns filled with graphitized thermal carbon black. The stereospecific features of the fragments of PHA and PHP are related, in particular, to the intramolecular repulsion of the H...H pairs of the side rings and evidently arise from the low energy of the ionizing electrons. The effect of this interaction is more clearly shown in the fragmentation of PHP, which is related to the angular disposition of the side rings, and which decreases as the structure of the isomers of the molecules becomes flatter. The predominant fragmentation paths, leading to a reduction in tension, arising from the intramolecular repulsion of the H...H pairs, are different for PHA and PHP. The fragmentation of PHA is characterized by the preferred rupture of the bonds of the side rings, while the fragmentation of PHP proceeds through the rupture of the bonds of the middle ring.
    Type of Medium: Electronic Resource
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  • 4
    ISSN: 1572-9567
    Keywords: critical phenomena ; equation of state ; ethane ; methane ; plait point ; thermodynamic properties
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract We present an equation of state for the thermodynamic properties of mixtures of methane and ethane in the critical region that incorporates the crossover from singular thermodynamic behavior near the locus of vapor-liquid critical points to regular thermodynamic behavior outside the critical region. The equation of state yields a satisfactory representation of the thermodynamic-property data for the mixtures in a large range of temperatures and densities.
    Type of Medium: Electronic Resource
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  • 5
    Electronic Resource
    Electronic Resource
    Springer
    International journal of thermophysics 14 (1993), S. 1187-1200 
    ISSN: 1572-9567
    Keywords: binary mixtures ; critical phenomena ; equation of state ; ethane ; methane ; plait point ; specific heat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract An isomorphic equation of state for near-critical binary mixtures is used to represent equation of state and specific heat data for mixtures of methane and ethane in a substantial range of densities and temperatures around the critical line.
    Type of Medium: Electronic Resource
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  • 6
    Electronic Resource
    Electronic Resource
    Springer
    International journal of thermophysics 14 (1993), S. 1187-1200 
    ISSN: 1572-9567
    Keywords: binary mixtures ; critical phenomena ; equation of state ; ethane ; methane ; plait point ; specific heat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract An isomorphic equation of state for near-critical binary mixtures is used to represent equation of state and specific heat data for mixtures of methane and ethane in a substantial range of densities and temperatures around the critical line.
    Type of Medium: Electronic Resource
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  • 7
    ISSN: 1572-9567
    Keywords: critical phenomena ; crossover equation ; ethane ; propane ; specific heat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract The specific heat at constant volume, Cv, of propane, and mixture with a concentration ofx=0.0081 cool fraction of propane was measured along the critical isochores at temperatures between 290 and 400 K. The measurements were performed with a high-temperature constant-volume adiabatic calorimeter. The uncertainty of most of the measurements is estimated to be less than 1.5%. Measurements have been carried out in both the one- and two-phase regions. The results for the pure components are compared with earlier measurements. Crossover equations forC, obtained on the basis of the renormalization-group method and ɛ-expansion are applied to represent our experimental specific heat data for ethane, propane. and its mixture along the critical isochores.
    Type of Medium: Electronic Resource
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  • 8
    Electronic Resource
    Electronic Resource
    Springer
    International journal of thermophysics 14 (1993), S. 1-32 
    ISSN: 1572-9567
    Keywords: critical phenomena ; equation of state ; ethane ; methane ; sound velocity ; specific heat ; thermodynamic properties
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract An improved parametric equation for the thermodynamic properties of fluids is presented that incorporates the crossover from singular thermodynamic behavior in the immediate vicinity of the critical point to regular thermodynamic behavior far away from the critical point. Based on a comparison with experimental data for ethane and methane, it is demonstrated that the crossover model is capable of representing the thermodynamic properties of fluids in a large range of temperatures and densities around the critical point.
    Type of Medium: Electronic Resource
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  • 9
    Electronic Resource
    Electronic Resource
    Springer
    International journal of thermophysics 9 (1988), S. 453-464 
    ISSN: 1572-9567
    Keywords: critical phenomena ; ethane ; heat capacity ; methane ; mixtures
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract Results of an experimental study of the isochotic heat capacity of methaneethane mixtures in a wide region around the liquid-gas critical line are presented. The data are represented by a universal scaled equation for critical mixtures.
    Type of Medium: Electronic Resource
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  • 10
    ISSN: 1612-1112
    Keywords: Geometric isomers ; Gas-solid chromatography ; Graphitized carbon black ; Packed capillaries ; Polycyclic hydrocarbons
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary Using the example of perhydrophenanthrene, perhydroanthracene and cyclopentanodecalin isomers a possibility is shown to use packed capillary columns containing graphitized thermal carbon black for a complete separation of high-boiling mixtures of polycyclic saturated hydrocarbon isomers in accordance with the geometric structure of their molecules.
    Type of Medium: Electronic Resource
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