Donatti, D. A.Vollet, D. R.Ruiz, A. I.2014-05-202014-05-202000-04-01Journal of Sol-gel Science and Technology. Dordrecht: Kluwer Academic Publ, v. 18, n. 1, p. 5-9, 2000.0928-0707http://hdl.handle.net/11449/38391The hydrolysis of TMOS in oxalic acid catalyzed reacting TMOS-water mixtures, under ultrasound stimulation, was studied by fitting a simplified dissolution and reaction modeling for samples, the hydrolysis rate of which had been measured in a previous work. The reaction pathway represented in a ternary diagram shows a heterogeneous step for the reaction which gradually progresses until complete homogenization of the system. Besides the water dissolved due to the homogenizing effect of the alcohol, ultrasound maintains a virtual and additional dissolution of water located at the interface between the TMOS and water during the heterogeneous step of the reaction. The mean radius of the heterogeneity represented by water dispersed in TMOS was evaluated as around 150 Angstrom. The oxalic acid concentration accordingly increases the hydrolysis rate constant but its fundamental role on the solubility of water in TMOS could not unequivocally be established.5-9engTMOShydrolysisultrasoundoxalic acidArtigo10.1023/A:1008717027627WOS:000086420200001Acesso restrito353810740116655326615737942333855890636096105376