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|Type:||Artigo de periódico|
|Title:||Chemisorption and thermodynamic data of the interaction between a chelate free acidic center with basic groups attached to grafted silicas|
de Sousa, AN
|Abstract:||The molecule 2-aminoethanethiol was added to the grafted silylant agent [(3-chlorosilylpropyl)trimethoxysilane] (cpts) onto silica gel(dropSil-Cl), obtaining a surface (dropSil-SNH2) and giving 0.70 mmol g(-1) of nitrogen; the surface of silica was modified with [(3-mercaptosilylpropyl)trimethoxysilane] (mpts) with surface (dropSil-SH), giving 0.78 mmol g(-1) of sulphur. Both matrices, (dropSil-SNH2) and (dropSil-SH), adsorb copper and cobalt acetylacetonates from ethanolic solution. Adsorption, using a batch-wise process, showed that copper chelate was the most adsorbed. The interactions between the basic centers attached to organic chains of these modified silicas with the cations in the chelates Me(acac)(2) [M = Cu and Co] were followed through calorimetric titrations. Exothermic enthalpic results were obtained for the dropSil-SNH2 matrix. The spontaneity of these systems was reflected in negative free Gibbs energy and positive from entropic values. (C) 2002 Elsevier Science (USA).|
|Editor:||Academic Press Inc Elsevier Science|
|Appears in Collections:||Unicamp - Artigos e Outros Documentos|
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