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  • 1
    Electronic Resource
    Electronic Resource
    Springer
    Colloid & polymer science 277 (1999), S. 1125-1133 
    ISSN: 1435-1536
    Keywords: Key words Surfactant ; Anthraquinone ; Surface activity ; Aggregation ; Redox activity
    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 Two new nonionic surfactants, α-anthraquinonyloxyhexyl-ω-hydroxy-oligo(ethylene oxide) (ACPEG) and α-anthraquinonyl-ω-hydroxy-oligo(ethylene oxide) (APEG), were synthesized. The fundamental interfacial behavior of these surfactants at the air/water interface has been investigated by means of surface tensiometry to provide an insight into the relationship between the structure of the hydrophobic moiety and the surfactant properties, with specific emphasis on the anthraquinone linkage. Aggregation numbers of the surfactants have been determined from static light scattering measurements. At a constant hydration of the ethylene oxide chain, the increase in the hydrophobic chain length in ACPEG raises its hydrophobic interaction and results in enhanced aggregation and significant variation in the interfacial and micellization properties compared to APEG. The electrochemical behavior of the surfactants has also been studied in 0.16 M NaCl aqueous solutions and in 0.1 M tetrabutylammonium perchlorate acetonitrile solutions at the interface of a glassy carbon electrode. A difference in the extent of aggregation has a pronounced effect on the cyclic voltammetric behavior of the surfactants in aqueous solution. In organic media, on the other hand, the redox process depends only on the molecular geometry of the monomeric species. A comparison of the electrochemical responses in the two phases has been made to explain the distinctive features of the redox properties of the surfactants.
    Type of Medium: Electronic Resource
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  • 2
    ISSN: 1612-1112
    Keywords: Column liquid chromatography ; Hydrous zirconium oxide ; Porous polymer resin ; Disubstituted phenols ; ortho-Benzoic acid derivatives
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary A porous polymer resin loaded with hydrous zirconium oxide (Zr-gel) was evaluated as a stationary phase for the liquid chromatographic separation of disubstituted aromatic compounds. The prepared Zr-gel was used to separate disubstituted phenols andortho-substituted benzoic acid derivatives in reversed-phase mode. The retention time of catechol was greater than those of other disubstituted phenols; this implies that the Zr-gel has specificity for the phenolic hydroxyl group. The retention behavior ofortho-substituted benzoic acid derivatives on the Zr-gel was also evaluated in reversedphase mode using buffer. Phthalic acid was specifically retained in the vicinity of pH 6.0, which has been regarded as the equal adsorbic point. Similar behavior was also observed for salicylic acid, although the retention time of salicylic acid was less than that of phthalic acid. It seems that the specific retention behavior of hydrous zirconium oxide is a result of complexation with ligands such as hydroxyl and carboxyl groups. The results of this study have revealed that the retention mechanism of hydrous zirconium oxide is a combination of ion exchange and interaction based on complexation with ligands.
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  • 3
    ISSN: 1612-1112
    Keywords: Column liquid chromatography ; Hydrous zirconium oxide ; Porous polymer resin ; Silica gel ; ortho-Benzoic acid derivatives
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary Silica gel loaded with hydrous zirconium oxide (Zr-gel-S) has been prepared and the influence of the base material on the retention behavior ofo-phthalic acid on the hydrous zirconium oxide was evaluated. The retention behavior of the acid on the Zr-gel-S was compared with that on Zr-gel-5, the polymer-based Zr-gel. Comparable retention behavior,i.e. maximum retention in the vicinity of pH 6, which has been regarded as the equal adsorbic point, was observed for both types of Zr-gel, although there was a large difference in the retention times. The difference in retention on the two types of Zr-gel could be ascribed to nature of the base material. The results in this experiments showed, however, that the specific behavior at pH 6 was an essential characteristic of hydrous zirconium oxide and was not related to the influence of the base materials.
    Type of Medium: Electronic Resource
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