ISSN:
1435-1536
Keywords:
Acidity
;
basicity
;
dipolarity
;
silica
;
polarity
;
solvatochromic dyes
;
acceptor numbers
;
donor numbers
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 Empirical “solvent” parameters of silica surfaces are determined by means of solvatochromic dyes, e.g., Cu(tmen) (acac)+ ClO 4 − /B(C6H5) 4 − , Fe(phen)2(CN)2, and Michlers Ketone dissolved in 1,2-dichloroethane or cyclohexane. The values obtained by UV/VIS-measurements are compared with both the polarity scales of Kamlet and Taft and with Gutmann's donor and acceptor numbers. Kamlet and Taft's α-parameter (the hydrogen-bond donation capacity of a solvent) is determined independently by means of salicylideneaniline. The π* of silica is determined using 5-N,N-dimethylamino-5′-nitro-2,2′-bithiophene and the complex of tetracyanoethylene with Michlers Ketone, respectively. Further on the reliabilities of the obtained Kamlet-Taft parameters α, β, and π* are checked by comparism with experimental and calculated values of theE T(30)-parameter of silica by means of multi-parameter regression analysis. The surface properties of silica are influenced mainly by HBD-properties α (75%) and dipolarity/polarizability π* (20%), but hardly by the HBA-properties β (〈5%). UV/VIS-measurements were carried out in a special equipment with glass fiber optics, A drawing of the apparatus is given.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00658910
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