A review on hydrolysis of tetraethyl orthosilicate in presence of ammonia as catalyst: effect of solvent on silica particle size

In the recent decades, hybrid organic/inorganic materials have been successfully prepared by sol–gel processes. These materials are synthesized by chemically incorporating organic polymers into inorganic networks. Tetrafunctional silicon compounds, for example alkoxysilanes, have been used as starting materials in this process. Furthermore, hydrolysis of alkoxysilanes has been observed, together with condensation reactions between Si–OH groups, which obtain a crosslinked and linear Si–O–Si structures. The hydrolysis of this tetrafunctional silicon compounds (particularly tetraethyl orthosilicate) has been the subject of numerous investigations. Therefore, in this work, a study on hydrolysis reactions of tetraethyl orthosilicate in the presence of ammonia by various alcoholic solvents was carried out and influence of these solvents on particle size of produced silica has been investigated. Under identical reaction conditions, the particle size was found to be strongly dependent on the specific properties and spatial characteristics of the solvent.