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Type: Artigo de periódico
Title: Synthesis, characterization and thermodynamics of the reaction of calcium methylphosphonate with n-alkylmonoamines
Author: Lima, CBA
Airoldi, C
Abstract: Lamellar crystalline calcium methylphosphonate, Ca[(HO)O2PCH3](2).H2O reacted with a series of n-monoalkylamines to yield the compounds Ca[(HO)O2PCH3](2). xH(2)N(CH2)(n)CH3. (1-x)H2O (n=0-4). Intense hands of the phosphonate group in the 1095-995 cm(-1) region in the infrared spectrum were detected. X-ray diffraction patterns showed a sharp and intense peak with an interlamellar distance of 907 pm. P-31 NMR spectrum gave a peak at 27.38 ppm for phosphonate groups. On heating methylphosphonate water molecules, organic moiety and P2O5 were released to yield a residue of pyrophosphate. The aminated compound presented the same sequence of mass loss, with amine being lost in the first stage. C-3 NMR spectrum presented peaks at:15 and 17 ppm for methylphosphonate groups. The original crystallinity of the compound is disturbed by the reaction with the n-alkylmonoamine, giving constant interlamellar distance. The energetic effect caused by amine was determined through. reaction-solution calorimetry in the solid-liquid interface from aqueous solution. The thermodynamic data showed that the system is favored by enthalpy, Gibbs free energy, and entropy values. (C) 2001 Elsevier Science Ltd. All rights reserved.
Subject: calcium methylphosphonate
Country: Inglaterra
Editor: Elsevier Sci Ltd
Citation: International Journal Of Inorganic Materials. Elsevier Sci Ltd, v. 3, n. 7, n. 907, n. 914, 2001.
Rights: fechado
Identifier DOI: 10.1016/S1466-6049(01)00089-7
Date Issue: 2001
Appears in Collections:Unicamp - Artigos e Outros Documentos

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