Access to Highly Fluorinated Silica by Direct F2 Fluorination
Résumé
Silica is one of the major components of the earth and has been extensively used in both heterogeneous catalysis and chemical separations [1–5]. Numerous applications of silica are related to the hydrophobic-hydrophilic balance and surface reactivity, which both obviously depend on the surface chemistry. Because of high surface area and porous structure, mesoporous silica properties are strongly dependent on the surface reactivity of silanol species (Si-OH) and their interactions via H-bonds with other molecules such as water [6–7]. The surface of silica exhibits low Brønsted acidity without any Lewis acidity.
However, surface modification reactions can be performed by using the Brønsted acidic sites of silica gels and such processes have been carried out to prepare thin coatings with a wide variety of organic groups and to adjust hydrophobic character [8]...