Effects of HCl on the ultrasound catalyzed TEOS hydrolysis as determined by a calorimetric study
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Data
1996-11-01
Autores
Donatti, D. A. [UNESP]
Vollet, D. R. [UNESP]
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Resumo
The acid catalyzed and ultrasound stimulated hydrolysis of solventless tetraethoxysilane-water mixtures was studied at 39°C as a function of HCl added to the mixtures (log[HCl]-1 ranged from 0.8 to 2.0), The reaction was carried out in a specially designed device, in which a steady state heat flow is maintained, while sonication is taking place, if no reaction is expected to occur. The exothermal hydrolysis reaction causes an increasing temperature (ΔTt) as a function of the reaction time, t. The isothermal hydrolysis rate constant, k, has been evaluated from the experimental ΔTt versus t data, after corrections for the increasing temperature effects, by using a method resulting from our theoretical modeling based on a dissolution and reaction mechanism. The hydrolysis rate constant fits closely a k α [H+] law as expected for this kind of hydrogen-ion catalyzed reaction.
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Calorimetry, Catalysis, Composition effects, Dissolution, Heat transfer, Hydrochloric acid, Mathematical models, Mixtures, Silanes, Water, Sonication, Tetrathoxysilane, Hydrolysis
Como citar
Journal of Non-Crystalline Solids, v. 208, n. 1-2, p. 99-104, 1996.