Article
Role of the Concentration and Nature of Grafted Groups in the Adsorption of Hydrocarbon Vapors on Silica Modified by Monofunctional Polyfluoroalkylsilanes
Russian Journal of Physical Chemistry A
(2012)
Abstract
The role of the grafting density of monofunctional polyfluoroalkylsilanes of the C nF 2n- 1(CH 2) mSi(CH 3) 2Cl general formula (where n = 3, 4, and 6; and m = 2 and 3) and their composition in intermolecular interactions of the molecules of saturated and aromatic hydrocarbons with a surface of chemically modified silica is studied by means of IR spectroscopy and adsorption-static and gas chromatography. It is shown that the higher the concentration and the shorter the length of the grafted chain, the greater (by a factor of 2 to 25) the drop in the adsorption values of hydrocarbons as a result of modifications, due to an increase in the degree of oleophobization of surface upon the formation of polyorganofluorine coatings. The high specificity of the surface with respect to benzene, which is due to the active participation of the polar fragment of a grafted chain in adsorption process, is related to the features of a relatively low-density sample with a concentration of grafted perfluorobutyl groups of 1.7 nm -2. It is shown that the thermodestruction of polyfluoroalkyl silica remains virtually unobserved upon heating to 523 K in an argon flow.
Keywords
- Silica gel,
- Paraffins,
- Contact angles
Disciplines
Publication Date
March, 2012
DOI
10.1134/S0036024412030260
Citation Information
Alexander Y. Fadeev, Tat'yana M. Roshchina, Nataliya K. Shoniya, O. Ya. Tayakina, et al.. "Role of the Concentration and Nature of Grafted Groups in the Adsorption of Hydrocarbon Vapors on Silica Modified by Monofunctional Polyfluoroalkylsilanes" Russian Journal of Physical Chemistry A Vol. 86 Iss. 3 (2012) p. 437 - 446 Available at: http://works.bepress.com/alexander_fadeev/11/