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Rubidium and lithium butanoates binary phase diagram

Formation of a stable lyotropic liquid crystal phase and two mixed salts

Journal of Thermal Analysis and Calorimetry
Authors: F. Martínez Casado, M. Ramos Riesco, and J. Cheda

Abstract  

The temperature and enthalpy vs. composition diagrams of the binary system [xC3H7CO2Li+(1–x)C3H7CO2Rb], where x=mole fraction, were determined by differential scanning calorimetry (DSC). This binary systems displays the formation of two mixed salts with a composition 1:1 and 1:2, which melt incongruently at Tfus=590.5 K, with ΔfusHm=11.6 kJ mol–1, and congruently at Tfus=614.5 K, with ΔfusHm=20.2 kJ mol–1, respectively. The phase diagram also presents an ionic liquid-crystalline phase in a wide temperature range: 95 K.

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Journal of Thermal Analysis and Calorimetry
Authors: J. Cheda, M. García Pérez, M. I. Yélamos, and A. Sánchez Arenas
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Journal of Thermal Analysis and Calorimetry
Authors: F. J. Martínez Casado, M. Ramos Riesco, M. I. Redondo Yélamos, A. Sánchez Arenas, and J. A. Rodríguez Cheda

Abstract

Four mesomorphic states of matter are known: liquid crystal, plastic crystal, condis phase, and rotator phase, all of them are solid phases, except liquid crystal, which is fluid. Plastic crystal (also called ODIC, orientational disordered crystal), rotator phase, and even condis phase have been considered the same phase by many authors. Differences between them will be established to define their own characteristics. Two organic salts series have been used for discussion in this presentation: (1) thallium(I) alkanoate series, that presents a condis mesophase, and (2) lead(II) alkanoate series, that present a rotator one, both forming a smectic A-like liquid crystal phase. Based in the literature data of the alkyl ammonium bromide series it can be established that the short chain length members would present a rotator phase, and, the large chain ones, a condis phase. Five different glass states are known (four with partial crystalline order), corresponding with the above mentioned mesophases, and the ordinary (amorphous) glass state.

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