Thermodynamic of obtaining of monodisperse particles SiO2 by tetraethoxysilane hydrolysis in the Si-OH-C-N system.
DOI:
https://doi.org/10.15276/opu.1.54.2018.10Keywords:
thermodynamics, Stober method, hydrolysis of tetraethoxysilaneAbstract
The problem of synthesizing of mono disperse SiO2 particles with hydrolysis (C2H5O)4Si by the Stober method is described.
The purpose of the study is to determine the conditions for the passage of this reaction in a water-ammonia-alcohol medium, at which the
maximum concentration of the solid phase of SiO2 and the minimum concentration of silicon ion compounds in solution are reached. By
thermodynamic modeling the composition of the Si-O-H-C-N system under thermodynamic equilibrium for various given conditions was
studied. The maximum amount of solid phase SiO2 at different initial concentrations (C2H5O)4Si is achieved at an initial concentration of
C2H5OH more than 1.2 mol/l, the concentration of the solid phase of SiO2 is proportional to the initial concentration (C2H5O)4Si.
Thermodynamic studies show that a change in the reaction temperature from 1 to 70 C does not affect the concentration of ionic silicon
compounds in the solution and the solid phase of SiO2. The obtained results reduce the search for optimal conditions for the production of
monodisperse particles of SiO2 and allow a deeper understanding of the processes taking place in the Si-O-H-C-N system.
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