ALBERT

All Library Books, journals and Electronic Records Telegrafenberg

X
feed icon rss

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
  • 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
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 2
    Electronic Resource
    Electronic Resource
    Study of adsorption from solutions by frontal chromatography (1985)
    Springer
    Chromatographia 20 (1985), S. 525-528 
    Details
    ISSN: 1612-1112
    Keywords: Liquid-solid chromatography ; Frontal analysis ; Adsorption isotherms ; Adsorption from solutions
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary The automatic frontal chromatography installation was described. By this chromatographic method the adsorption isotherm of benzene from n-heptane solutions on hydroxylated surface of silica with various porosity has been determined. This investigation was performed at different flow rates of eluent and in a wide range of concentrations. The isotherm of adsorption obtained by this chromatographic method has been compared with the results of the static measurements. The coincidence of adsorption isotherms measured at the various flow rates are shown to be a criterion of proximity the chromatographic process to the equilibrium.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02312170
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 3
    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
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 4
    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
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 5
    Electronic Resource
    Electronic Resource
    Separation of unsaturated and aromatic hydrocarbons on capillary columns packed with barium sulphate (1985)
    Springer
    Chromatographia 20 (1985), S. 519-524 
    Details
    ISSN: 1612-1112
    Keywords: Gas adsorption chromatography ; Packed capillary columns ; Modification of BaSO4 ; Separation of isomeric unsaturated and aromatic hydrocarbons ; Selectivity and dipole moment
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary Isomeric hydrocarbons with molecules having similar geometry but differing in the electron density distribution were separated on capillary columns packed with barium sulphate, a non-porous ionic adsorbent. Samples of BaSO4 were washed free of foreign ions and modified by solutions of alkaline metal halides. The selectivity of the separation of unsaturated and aromatic hydrocarbons can be controlled by varying the conditions of the BaSO4 treatment. Capillary columns packed with the ionic adsorbent were successfully used to separate all xylene and butene isomers, as well as isomers of cis and trans octene-2.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02312169
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 6
    Electronic Resource
    Electronic Resource
    Chromatographic determination of the thermodynamic adsorption characteristics of saturated tricyclic hydrocarbon isomers using capillary columns with graphitized carbon black (1983)
    Springer
    Chromatographia 17 (1983), S. 533-538 
    Details
    ISSN: 1612-1112
    Keywords: Gas adsorption chromatography ; Molecular structure and adsorption ; Graphitized carbon black ; Capillary packed adsorption columns ; Tricyclic hydrocarbon separation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary Due to their high efficiency capillary columns packed with graphitized thermal carbon black (GTCB) permit to realize high selectivity in the chromatographic separation of isomers on the flat surface of this adsorbent. However, the increase in the efficiency is connected to a considerable increase of the pressure drop across the column which hinders the determination of the thermo-dynamic adsorption characteristics. The optimum conditions for the preparation of such columns designed both for analytical purposes and for thermodynamic measurements of the individual isomers have been established. The retention volumes for small (zero) sample size (Henry constants for adsorption on GTCB) of six isomers of tricyclo(8,4,0,02,7)tetradecane (perhydrophenanthrene), seven isomers of tricyclo-(7,4,0,02,6)tridecane (1,2-cyclopentanodecalin) and six isomers of tricyclo(7,3,0,02,6)dodecane have been determined. The Henry constants increase with the flattening of the isomeric molecules in these hydrocarbon series. A qualitative procedure of identification of the isomers on the basis of optimum orientation of their molecules on a flat surface has been considered.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02261915
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 7
    Electronic Resource
    Electronic Resource
    Die Retention von Indan- und Inden-Kohlenwasserstoffen auf graphitiertem thermischen Ruß (1980)
    Springer
    Chromatographia 13 (1980), S. 493-496 
    Details
    ISSN: 1612-1112
    Keywords: Gas adsorption chromatography ; Graphitized thermal carbon black ; Indan ; Indan-type hydrocarbons
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Zusammenfassung Es werden die Werte der Retentionsvolumina, der Retentionsindices und andere thermodynamische Adsorptionscharakteristiken von zehn Indan- und Inden-Kohlenwasserstoffen mit 9–11 Kohlenstoffatomen auf graphitiertem thermischem Ruß (GTR) bestimmt. Es wurde festgestellt, daß auf GTR die Kohlenwasserstoffe der Inden-Reihe am stärksten adsorbiert werden und am schwächsten cis-Hydrandan, was mit den Besonderheiten der geometrischen Struktur dieser Verbindungen zusammenhängt. Es wird die Möglichkeit der Anwendung von GTR für die vollständige Trennung der cis- und trans-Isomeren von Hydrindan gezeigt.
    Notes: Summary The retention volumes, retention indices and other thermodynamic values characteristic of the adsorption of ten indan-hydrocarbons having 9–11 carbon atoms were determined on graphitized thermal carbon black (GTCB). It is shown that GTCB adsorbs strongest the hydrocarbons of the indan series and weakest cis hydrindan. This is related to the peculiarities of the geometric structure of the compounds. The possibility of the application of GTCB for the complete separation of cis and trans hydrindan is shown.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02261620
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 8
    Electronic Resource
    Electronic Resource
    Chromatographic determination and molecular-statistical calculation of retention volumes of oxygen-containing organic substances on graphitized thermal carbon black part 1: Cyclic ethers and ketones (1983)
    Springer
    Chromatographia 17 (1983), S. 526-532 
    Details
    ISSN: 1612-1112
    Keywords: Gas adsorption chromatography ; Graphitized thermal carbon black ; Cyclic ethers and ketones ; Atom-atom oxygen … carbon potentials
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary The paper is concerned with molecular-statistical determination of retention volumes of oxygen-containing organic substances such as cyclic ethers and ketones by presenting the potential energy of intermolecular interaction of the molecules with a monoatomic adsorbent having homogeneous flat surface (graphitized thermal carbon black) as a sum of atom-atom potentials. In order to eliminate the specific interactions of ethers and ketones with the traces of surface oxygen compounds on graphitized thermal carbon black, the latter was treated additionally with hydrogen. Comparison is made between the experimentally measured retention volumes and the Henry constants calculated for reference molecules of ethers (dioxane) and ketones (cyclohexanone) to correct the atom-atom potentials. It is shown that the atom-atom potentials obtained for the reference molecules can be used for other ethers and ketones of known structure with the subsequent calculation of the corresponding values of the retention volumes in terms of molecular statistics. When the structure is not known its parameters are optimized using the chromatostructural method (chromatoscopy). The calculated heat of adsorption values agree well with those determined from the chromatographic measurements. Chromatograms showing the full separation of mixtures of the ethers and ketones studied were obtained.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02261914
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...