Please use this identifier to cite or link to this item: http://repositorio.unicamp.br/jspui/handle/REPOSIP/73550
Type: Artigo de periódico
Title: The intercalation of some heterocyclic amines into alpha-titanium hydrogenphosphate - Structural and calorimetric data
Author: Nunes, LM
Airoldi, C
Abstract: The intercalation of the heterocyclic amines 2,6-lutidine, pyrazine, piperazine, and piperidine into or-titanium hydrogenphosphate gave the maximum amounts intercalated in aqueous solutions of 0.45, 0.65, 2.77, and 6.52 mmol g(-1), respectively, through a batch method at 298 +/- 1 It. 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 - 31.44 +/- 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 host O3P-OH of the inorganic matrix and the basic center atoms of the guest molecules. (C) 2000 Academic Press.
Subject: layered compounds
intercalation
alpha-titanium hydrogenphosphate
calorimetry
heterocyclic amine
Country: EUA
Editor: Academic Press Inc
Rights: fechado
Identifier DOI: 10.1006/jssc.2000.8879
Date Issue: 2000
Appears in Collections:Unicamp - Artigos e Outros Documentos

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