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|Type:||Artigo de periódico|
|Title:||The Intercalation Of Some Heterocyclic Amines Into α-titanium Hydrogenphosphate - Structural And Calorimetric Data|
|Abstract:||The intercalation of the heterocyclic amines 2,6-lutidine, pyrazine, piperazine and piperidine into α-titanium hydrogenphosphate gave the maximum amounts intercalated in aqueous solutions of 0.4 ,0.65, 2.77, and 6.52 mmol g-1, respectively, through a batch method at 298 ± 1 K. The original interlamellar distance of 760 pm increased after intercalation of piperazine and piperidine molecules, while for 2,6-lutidine and pyrazine molecules no change was observed. These results suggested that the amines were bonded only on the surface of the host. All thermochemical data were obtained on a differential isothermic microcalorimetric instrument by means of a titration procedure. From thermal effect data, the variation in enthalpy for each system gave exothermic values of - 6.56 ± 0.10, - 1.00 ± 0.10, - 10.10 ± 0.34, and -31.4.4 ± 0.71 kJ mol-1 for intercalations of the above sequence of heterocyclic amines. The infrared spectra are in agreement with acid-base reactions, involving the layered acid hos O3P-OH of the inorganic matrix and the basic center atoms of the guest molecules. (C) 2000 Academic Press.|
|Appears in Collections:||Unicamp - Artigos e Outros Documentos|
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