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  • 13C NMR spectroscopy  (2)
  • alkyltrimethylammonium ion  (1)
  • esterification  (1)
  • 1
    Electronic Resource
    Electronic Resource
    Polymerization Reactions in an Al(OBus)3-(COOH)2 System (1997)
    Springer
    Journal of sol gel science and technology 8 (1997), S. 95-99 
    Details
    ISSN: 1573-4846
    Keywords: aluminum sec-butoxide ; oxalic acid ; 13C NMR spectroscopy ; 27Al NMR spectroscopy ; polymerization
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract Reactions in an Al(OBus)3-(COOH)2 (OA)-tetrahydrofuran (THF)/(CD3)2SO (DMSO-d6) system (Al(OBus)3: THF : DMSO-d6: OA = 1 : 5 : 5 : x, x = 0.01 –3) were studied, without the addition of water and the process was monitored by NMR. When x ≤ 0.3, homogeneous solutions were obtained, whereas white precipitates formed with x ≥ 0.7. The formation of sec-butyl alcohol was evident with x ≥ 0.6, indicating that oxalate groups coordinate to aluminum to release sec-butyl alcohol. 13C NMR spectra of the solutions after 1 day suggest the presence of polymeric species if 0.03 ≤ x ≤ 0.6. The addition of a small amount of water resulted in the formation of a white precipitate (Al(OBus)3: THF : DMSO-d6 : OA : H2O = 1 : 5 : 5 : 0.3 : y,y = 0.03–0.3), indicating that water, possibly formed by esterification in the Al(OBus)3-OA-THF/DMSO-d6 system, does not take a major role in the present system.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1026415608082
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    Paper (German National Licenses)
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  • 2
    Electronic Resource
    Electronic Resource
    Polymerization reactions in an Al(OBu s )3−(COOH)2 system (1997)
    Springer
    Journal of sol gel science and technology 8 (1997), S. 95-99 
    Details
    ISSN: 1573-4846
    Keywords: aluminum sec-butoxide ; oxalic acid ; 13C NMR spectroscopy ; 27Al NMR spectroscopy ; polymerization
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract Reactions in an Al(OBu s )3−(COOH)2 (OA)-tetrahydrofuran (THF)/(CD3)2SO (DMSO-d6) system (Al(OBu s )3∶THF∶DMSO-d6∶OA=1∶5∶5∶x, x=0.01–3) were studied, without the addition of water and the process was monitored by NMR. Whenx≤0.3, homogeneous solutions were obtained, whereas white precipitates formed withx≥0.7. The formation of sec-butyl alcohol was evident withx≥0.6, indicating that oxalate groups coordinate to aluminum to release sec-butyl alcohol.13C NMR spectra of the solutions after 1 day suggest the presence of polymeric species if 0.03≤x≤0.6. The addition of a small amount of water resulted in the formation of a white precipitate (Al(OBu s )3∶THF∶DMSO-d6∶OA∶H2O=1∶5∶5∶0.3∶y, y=0.03–0.3), indicating that water, possibly formed by esterification in the Al(OBu s )3-OA-THF/DMSO-d6 system, does not take a major role in the present system.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02436824
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    Paper (German National Licenses)
    Fulltext
  • 3
    Electronic Resource
    Electronic Resource
    Esterification of the Silanol Groups in the Mesoporous Silica Derived from Kanemite (1998)
    Springer
    Journal of porous materials 5 (1998), S. 127-132 
    Details
    ISSN: 1573-4854
    Keywords: mesoporous silica ; esterification ; pore size ; hydrophobicity ; silanol group
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract Silanol groups in the mesoporous silica derived from a layered silicate, kanemite (NaHSi12O5 ċ3H2O), were esterified with alcohols (CnH2n+1OH n=2 , 4, and 8). Most of the silanol groups in the mesopores were modified with ethanol though some silanol groups remained after the reactions with 1-butanol and 1-octanol. With the increase in the alkyl chain lengths of the alcohols, the pore sizes of the esterified products decreased and the hydrophobicity increased.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1009641304742
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    Paper (German National Licenses)
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  • 4
    Electronic Resource
    Electronic Resource
    Silica-based mesoporous molecular sieves derived from a layered polysilicate kanemite—A review (1996)
    Springer
    Journal of porous materials 3 (1996), S. 107-114 
    Details
    ISSN: 1573-4854
    Keywords: mesoporous material ; kanemite ; layered polysilicate ; surfactant ; alkyltrimethylammonium ion
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract Synthesis of highly ordered mesoporous materials derived from a layered polysilicate kanemite has been reviewed. Silica-surfactant mesostructured materials are obtained by the reaction of kanemite with alkyltrimethy lammonium ions. Calcination of silica-surfactant mesophase materials yields ordered mesoporous molecular sieves. Substantial replacement of alkyltrimethylammonium ions for interlayer Na ions and careful adjustment of pH in the reaction media are necessary for the preparation of ordered mesoporous silica. Formation processes of the silicate-surfactant mesophase materials have been monitored by in-situ powder X-ray diffraction technique which has indicated the presence of a lamellar phase before the appearance of a hexagonal phase. Comparison of these materials with MCM-41 is briefly mentioned. The properties and potential applications of these materials are also briefly outlined.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01186040
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    Paper (German National Licenses)
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