resumo
The complete solid-liquid phase diagrams for four binary mixtures of saturated fatty acids are presented, for the first time, in this work. These mixtures are formed by caprylic acid (C(8:0)) + lauric acid (C(12:0)). capric acid (C(10:0)) + myristic acid (C(14:0)), lauric acid (C(12:0)) + palmitic acid (C(16:0)) and myristic acid (C(14:0)) + stearic acid (C(18:0)). The phase diagrams were obtained by differential scanning calorimetry (DSC) and X-ray diffraction (XRD). FT-Raman spectrometry and polarized light microscopy were used to complement the characterization for a complete understanding of the phase diagram. All of the phase diagrams here reported show the same global behavior that is far more complex than previously accepted. They present not only peritectic and eutectic reactions, but also metatectic reactions, clue to solid-solid phase transitions common in fatty acids, and regions of solid solution not previously reported. This work contributes to the elucidation of the phase behavior of these important biochemical molecules with implications in various industrial applications. (c) 2008 Elsevier Ireland Ltd. All rights reserved.
palavras-chave
LAURIC-ACID; OLEIC-ACID; STEARIC-ACID; CRYSTAL-STRUCTURE; CAPRIC ACID; BEHAVIOR; FORM; SYSTEMS; POLYMORPHISM; EQUILIBRIA
categoria
Biochemistry & Molecular Biology; Biophysics
autores
Costa, MC; Sardo, M; Rolemberg, MP; Ribeiro-Claro, P; Meirelles, AJA; Coutinho, JAP; Krahenbuhl, MA
nossos autores
Mariana Coutinho Sardo
Investigador Auxiliar
Paulo Ribeiro-Claro
Professor Associado com AgregaçãoGrupos
G1 - Materiais Porosos e Nanossistemas
G4 - Materiais Renováveis e Economia Circular
G6 - Materiais Virtuais e Inteligência Artificial
agradecimentos
The authors are grateful to CNPq (nos. 141607/2004-1, 142823/2005-8 and 303649/2004-6), FAPESP (no. 2005/530952), CAPES-GRICES (0148/06-7), FAEPEX/UNICAMP FEDER and FundaGao para a Ciencia e a Tecnologia through project POCI/CTM/ 60288/2004 and PhD grant SFRH/BD/23400/2005 for financial support.