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  • charge reduction  (2)
  • synthesis  (2)
  • Bronsted acid catalysts  (1)
  • Family behavior  (1)
  • 1
    Electronic Resource
    Electronic Resource
    Ionic migration and charge reduction in Ni2+-, Co2+- and Zn2+-exchanged Texas montmorillonite (1993)
    Springer
    Catalysis letters 18 (1993), S. 235-241 
    Details
    ISSN: 1572-879X
    Keywords: Montmorillonite ; clay ; charge reduction ; cation migration
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract Controlled calcination of ion-exchanged Texas montmorillonite leads to layer charge reduction. Detailed chemical analyses of both exchangeable and unexchangeable metal species lead to the conclusion that, in complete contrast to the situation with Wyoming bentonite, Ni2+, Co2+ and Zn2+ are all capable of migrating from the interlamellar space into the octahedral region of the sheets where they are (i) isomorphously exchanged for Mg2+, and to a proportionately smaller extent, for Fe2+, (ii) trapped in the octahedral vacancies. In addition, they are converted to unexchangeable species on the interlamellar sheet surfaces by high temperature hydrolysis leading to hydroxide or oxide formation. It is suggested that protons within the octahedral region are bound as -OH+ 2rather than simply physically trapped.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00769442
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  • 2
    Electronic Resource
    Electronic Resource
    The mechanism of layer charge reduction and regeneration in Li+-exchanged montmorillonite (1991)
    Springer
    Catalysis letters 9 (1991), S. 115-119 
    Details
    ISSN: 1572-879X
    Keywords: Clays ; montmorillonites ; charge reduction ; charge regeneration ; lithiation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract Thermally induced migration of Li+-cations from the interlamellar region into the sheet structure of montmorillonite clays has long been known to lead to charge reduction which, depending on conditions, may be partial or virtually complete. Charge regeneration by treatment with strong base involves H+-extraction from the sheets and detailed structural and interlamellar analysis establishes a 1∶1 balance between Li+ and H+ arising from the structural exchange -OH + Li+→-OLi + H+. Such lithiated clays are substantially more thermally and solvent stable than their precursors.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00769089
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  • 3
    Electronic Resource
    Electronic Resource
    Some observations on the synthesis and characterisation of pillared layered materials of varied pillar density (1992)
    Springer
    Catalysis letters 14 (1992), S. 11-13 
    Details
    ISSN: 1572-879X
    Keywords: Pillared layered materials ; synthesis ; characterisation ; pillar density
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract A practical approach to the synthesis from a given layered host of pillared derivatives of varied, and controlled, pillar density is described. An analytical technique allowing measurement of the pillar density is outlined and it is shown that, if the stoichiometric composition of the host is known, the measurements permit elucidation of the charge on the ionic pillar precursor. Once established for fixed conditions of synthesis this would allow calculation of pillar density from a knowledge of the cation exchange capacity of the original host.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00764213
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  • 4
    Electronic Resource
    Electronic Resource
    Catalysis by ion-exchanged montmorillonites (1990)
    Springer
    Catalysis letters 5 (1990), S. 203-210 
    Details
    ISSN: 1572-879X
    Keywords: Montmorillonite ; swectite ; Bronsted acid catalysts ; intercalation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract In this short review the special attributes that make modified layered clays such versatile and effective catalysts for the conversions of organic molecules are discussed and exemplified.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00763954
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  • 5
    Electronic Resource
    Electronic Resource
    Synthesis and characterisation of alumina pillared Texas montmorillonite and determination of the effective Keggin ion charge (1993)
    Springer
    Catalysis letters 18 (1993), S. 137-140 
    Details
    ISSN: 1572-879X
    Keywords: Montmorillonites ; layered materials ; pillared layered materials ; synthesis ; pillar precursor charge ; pillar density
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract Controlled calcination of Texas montmorillonite has allowed production of a range of materials of cation exchange capacity from ≈ 70 mequiv./100 g dry clay to virtually zero. Pillaring of these with Chlorhydrol precursor solution has then provided a family of materials of pillar density ranging from about one per six unit cells to zero. The analytical technique based on isomorphous metal dilution (IMD) that follows pillaring is validated. The results provide a consistent value for the precursor (Keggin) ion charge, in the conditions normally used, of 3.15±0.10 rather than the “formal” value of 7. An approach to the attainment of pillar densities consistent with the introduction of shape/size selectivity on pillared layered materials is outlined.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00769506
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  • 6
    Electronic Resource
    Electronic Resource
    Specific retention volumes, retention indices, and family-plot regressions of aliphatic, alicyclic, and aromatic hydrocarbon solutes with OV-101 poly (dimethylsiloxane) stationary phase (1988)
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 11 (1988), S. 649-660 
    Details
    ISSN: 0935-6304
    Keywords: Gas chromatography ; Homologized series ; Retention volumes ; Family behavior ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jhrc.1240110908
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