A kinetic model for the ultrasound catalyzed hydrolysis of solventless TEOS-water mixtures and the role of the initial additions of ethanol

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dc.contributor.authorVollet, D. R.
dc.contributor.authorDonatti, D. A.
dc.contributor.authorCampanha, JR
dc.contributor.institutionUniversidade Estadual Paulista (Unesp)
dc.date.accessioned2014-05-20T15:23:52Z
dc.date.available2014-05-20T15:23:52Z
dc.date.issued1996-01-01
dc.description.abstractThe acid and ultrasound catalyzed hydrolysis of solventless TEOS-water mixtures are studied, as a function of the initial additions of ethanol to the mixtures, by means of flux calorimetry measurements. A device was specially designed for this purpose. Under acid conditions, our proposed method has been able to resolve hydrolysis from other condensation reactions, by detecting the exothermal hydrolysis reaction heat. The process has been explained by a dissolution and reaction mechanism. Ultrasound forces the dissolution process to start the reaction. The alcohol produced in the reaction helps the dissolution process to further enhance the hydrolysis. Initial amounts of pure ethanol added to the mixtures shorten the start time of the reaction, due to an additional effect of dissolution, and diminish the reaction rate, as a result of the solvent dilution effect. Our dissolution and reaction mechanism modeling describes the main points arising from the experimental data and yields k(H) = 0.24 M(-1) min(-1) for the second-order hydrolysis rate constant at 39 degrees C.en
dc.description.affiliationUNIV ESTADUAL PAULISTA,DEPT FIS,CAMPUS RIO CLARA,CX P 178,BR-13500970 RIO CLARO,SP,BRAZIL
dc.description.affiliationUnespUNIV ESTADUAL PAULISTA,DEPT FIS,CAMPUS RIO CLARA,CX P 178,BR-13500970 RIO CLARO,SP,BRAZIL
dc.format.extent57-63
dc.identifierhttp://dx.doi.org/10.1007/BF00402589
dc.identifier.citationJournal of Sol-gel Science and Technology. Dordrecht: Kluwer Academic Publ, v. 6, n. 1, p. 57-63, 1996.
dc.identifier.doi10.1007/BF00402589
dc.identifier.issn0928-0707
dc.identifier.lattes2661573794233385
dc.identifier.lattes3538107401166553
dc.identifier.urihttp://hdl.handle.net/11449/34563
dc.identifier.wosWOS:A1996TY35200003
dc.language.isoeng
dc.publisherKluwer Academic Publ
dc.relation.ispartofJournal of Sol-Gel Science and Technology
dc.relation.ispartofjcr1.745
dc.relation.ispartofsjr0,477
dc.rights.accessRightsAcesso restrito
dc.sourceWeb of Science
dc.subjecthydrolysispt
dc.subjectTEOSpt
dc.subjectcalorimetrypt
dc.subjectethanol additionspt
dc.titleA kinetic model for the ultrasound catalyzed hydrolysis of solventless TEOS-water mixtures and the role of the initial additions of ethanolen
dc.typeArtigo
dcterms.licensehttp://www.springer.com/open+access/authors+rights
dcterms.rightsHolderKluwer Academic Publ
unesp.author.lattes2661573794233385
unesp.author.lattes3538107401166553
unesp.campusUniversidade Estadual Paulista (Unesp), Instituto de Geociências e Ciências Exatas, Rio Claropt

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Artigos - Física - IGCE