Spectroscopic study on peculiarities of fumed silica hydridesilylation with triethoxysilane under fluidized bed conditions

Fumed silica has found widespread application in industry due to variety of fascinating properties. Owing its specific manufacturing process, it consists finely dispersed particles and is featured with large surface area covered by profoundly reactive silanol groups which are available for chemical grafting. Spherical shape fumed lacking porosity provides a space-filling structure. These characteristics implement the fume silica’s utilization as high-surface-area carriers various catalysts, i.e. metallic nanometer-sized particles, organic moieties, etc. Currently great attention called on-surface grafting improve silica-based carrier. Most research carried out liquid phase chemistry involving an abundance expensive often toxic solvents while properties favoring reactions fluidized bed conditions. In current (A-300) was subject hydridesilylation triethoxysilane under all synthesis reported insignificant amount solvent (1.00 wt. % used typical wet-chemical modifications method) spent silylation. While mass ratio silica/TES kept constant, other conditions, solvent/catalyst presence, pretreatment, additional treatment water, heating mode have been varied. FTIR spectroscopy revealed interaction between demonstrated effect modification conditions on density hydridesilyl coverage. The results spectroscopic studies confirmed presence grafted silicon hydride modified silica, well ethoxy and/or – either intact or formed hydrolysis groups. Titrimetric spectrophotometric analysis performed estimate concentration SiH (in samples prepared their ranged within about 0.28–0.55 mmol/g dependent reaction conditions). Other important aspects fluidization such hydrolyzing agent, sample thermal pre-treatment also discussed.