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  • 1
    Electronic Resource
    Electronic Resource
    Intermolecular interactions in liquid adsorption chromatography (1983)
    Springer
    Chromatographia 17 (1983), S. 143-148 
    Details
    ISSN: 1612-1112
    Keywords: Liquid chromatography ; Intermolecular interactions ; Adsorption from solutions ; Chemically modified layers in LC ; Conformation of bonded chains
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary For the investigation of intermolecular interactions in adsorption from solution, which are the basis of selectivity in molecular liquid chromatography (LC), it is convenient to use the LC method itself. Using this method the Henry's constants, K1, and other thermodynamic adsorption characteristics of hydrocarbons and of a series of polar substances on hydroxylated silica surface were determined from aqueous solutions. On the basis of the adsorption of hydrocarbons from water solutions the structure of the chemically modifying layers formed by different hydrocarbon groups on the silica surface is considered. The role of conformation ability of straight-chain bonded phases is demonstrated. Hydrocarbons are adsorbed on the hydroxylated silica surface more strongly from aqueous solutions than from solutions in saturated hydrocarbons and their retention increases with the increase in the number of carbon atoms in the molecule. The retention in LC is determined by the intermolecular interaction of the solute and solvent molecules with the adsorbent, as well by the contribution of the intermolecular interaction, between the solute and the solvent. The thermodynamic characteristics of adsorption of cymarin from water-ethanol solutions on hydroxylated silica gel and on silica gel surface modified by diphenylsilyl groups is compared. The solubility of silica gel modified by diphenylsilyl groups at different composition of water-ethanol eluent at different temperatures is investigated.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02271037
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  • 2
    Electronic Resource
    Electronic Resource
    Physico-chemical applications of liquid chromatography I. Investigation of the adsorption of cardiac glycosides from water-ethanol solutions on silanized silica (1980)
    Springer
    Chromatographia 13 (1980), S. 745-751 
    Details
    ISSN: 1612-1112
    Keywords: Adsorption from solutions ; Liquid chromatography ; Cardiac glycosides
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary Using the cardiac glycoside cymarin as the example the application of liquid chromatography for the study of adsorption from solutions and the determination of the corresponding thermodynamic characteristics was investigated. The adsorption isotherm of cymarin at small concentrations from a water-ethanol solvent on silica gel modified by dimethyldichlorosilane was measured under static conditions using analytical LC to determine the concentrations of solutions after adsorption. The values of the Henry constants were obtained by extrapolating the slope of the adsorption isotherm down to zero concentration. The specific retention volumes for different but small sample sizes of cymarin in the chromatographic column were measured, the adsorbent and the water-ethanol eluent being the same as in the static conditions. The specific retention volume for a small (zero) sample size determined by liquid chromatography experiment coincides with the Henry constant of cymarin adsorption determined in static conditions. In favourable cases liquid chromatography can be used to determine the equilibrium constants for adsorption from solution. The dependence of the Henry constants on temperature was investigated for several cardiac glycosides. The influence of the modification of the adsorbent surface on the separation of the cardiac glycosides was also studied.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02265553
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  • 3
    Electronic Resource
    Electronic Resource
    Influence of intermolecular interaction with the eluent on the retention of phenol and aniline on polar and non-polar surfaces (1983)
    Springer
    Chromatographia 17 (1983), S. 312-314 
    Details
    ISSN: 1612-1112
    Keywords: Selectivity in liquid chromatography ; Intermolecular interactions with eluent ; Adsorption from solutions
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary The retention order of aniline and phenol on hydroxylated silica gel surface is reversed with the increase of the concentration of a polar component in the eluent. At minor (about 1%) concentrations of isopropanol in hexane aniline emerges first followed by phenol, the elution order being reversed with the increase of isopropanol concentration above 2%. The same behaviour is observed for silica gel with chemically bonded C16 n-alkyl groups and for porous styrene-divinylbenzene copolymer. In all these cases the retention depends to a great extent on substance-eluent intermolecular interactions. At high isopropanol concentration in hexane the rise of column temperature changes the retention order of aniline and phenol on silica gel with hydroxylated surface since the association of these molecules with isopropanol as well as the isopropanol adsorption weaken as the temperature increases.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02270664
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  • 4
    Electronic Resource
    Electronic Resource
    Reactive polymers, XXXVIII.Part XXXVII: Angew. Makromol. Chem. 95 (1981) 129. Sorption of acid gases on macroporous 2,3-epoxypropyl methacrylate copolymers modified by a reaction with amines (1981)
    Weinheim : Wiley-Blackwell
    Angewandte Makromolekulare Chemie 96 (1981), S. 69-84 
    Details
    ISSN: 0003-3146
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Description / Table of Contents: Eine Aminolyse von makroporösen Copolymeren aus Glycidylmethacrylat und Ethylendimethacrylat führte zu Sorbentien mit einem unterschiedlichen Gehalt an Amino-und Hydroxygruppen. Es wurde die Abhängigkeit zwischen strukturellen Parametern und der Schwefeldioxidsorption auf der einen und der Konzentration des Vernetzungsmittels und der porogenen Lösungsmittel in der Polymerisationsmischung auf der anderen Seite untersucht. Die Schwefeldioxidsorption hängt von der geometrischen Struktur des Sorbens, der Konzentration, der chemischen Struktur und der Erreichbarkeit der funktionellen Gruppen ab.
    Notes: Macroporous copolymers of 2,3-epoxypropyl methacrylate and ethylenedimethacrylate modified by aminolysis yielded sorbents with various contents of amino and hydroxy groups. The dependences of structural characteristics of these sorbents and of the sorption of sulphur dioxide on the content of crosslinking agent and on the cyclohexanol/dodecanol ratio used as the porogenic medium in the preparation of copolymers were investigated. The sorption of sulphur dioxide depends on the geometrical structure of the sorbent, concentration, chemical structure and accessibility of functional groups.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/apmc.1981.050960106
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  • 5
    Electronic Resource
    Electronic Resource
    Vibrational Spectra of Crystalline Hexachlorocerates(IV), R2CeCl6 (1981)
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 474 (1981), S. 233-240 
    Details
    ISSN: 0044-2313
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Schwingungsspektren kristalliner Hexachlorocerate(IV), R2CeCl6Eine vollständige Zuordnung aller Fundamentalbanden in den Spektren kristalliner R2CeCl6, die zu den Ce—Cl-Schwingungen gehören, wurde unter Benutzung von Daten über Kombinationsschwingungen und im Raman-Spektrum aktiver Oberschwingungen vorgenommen. Die Vermutung über die Existenz einer isolierten [CeCl62-]-Gruppe, die in Kristallen mit einer genügend hohen Gitterpunktsymmetrie eine oktaedrische Struktur aufweist, konnte bestätigt werden. Auf der Grundlage des experimentellen Materials und seiner Deutung wird die Vermutung über das Auftreten eines Pseudo-Jahn-Teller-Effektes in der Hexachloroceraten(IV) geäußert.
    Notes: A complete assignment of all fundamentals in the spectra of crystalline R2CeCl6 belonging to the Ce—Cl vibrations was undertaken using data about combination bands and active in the Raman spectrum overtones. The assumption of the presence of a separate [CeCl62-] group possessing an octahedral structure in crystals with a sufficient high site symmetry has been confirmed. Based on the experimental material and its interpretation a presumption concerning the appearence of a pseudo-Jahn-Teller effect in the hexachlorocerates(IV) was supposed.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/zaac.19814740326
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