resumo
Liquid + liquid equilibrium of the system [Bmim][BF4] + 1H, 1H, 2H, 2H perfluoroctanol using a highly precise methodology based on refractive index measurements was experimentally determined. In addition, isobaric heat capacity near the critical point was obtained. The performance of the new refractive index set-up was successfully checked against the coexistence curve of the system dimethyl carbonate + decane, since highly accurate data are available in the literature. The choice of [Bmim][BF4] + 1H, 1H, 2H, 2H perfluoroctanol was motivated by a previous experimental work, whose results suggest that this system could present characteristics of both solvophobic and coulombic behavior, which are the two categories to which an ionic system can belong. Although this was previously observed for other ionic systems, this mixture presented a very striking feature: the diameter of the coexistence curve seemed to change its criticality in the studied temperature range, from solvophobic far away to coulombic close to the critical point. The results of this work reveal that, in fact, [Bmim][BF4] + 1H, 1H, 2H, 2H perfluoroctanol presents characteristics of both solvophobic and coulombic criticality, but no evidence of the observed crossover over the experimental temperature range has been found. (c) 2013 Elsevier Ltd. All rights reserved.
palavras-chave
COEXISTENCE CURVES; IONIC LIQUIDS; TEMPERATURE; ALCOHOLS; DECANE; FLUIDS
categoria
Thermodynamics; Chemistry
autores
Perez-Sanchez, G; Troncoso, J; Losada-Perez, P; Mendez-Castro, P; Romani, L
nossos autores
Germán Pérez-Sánchez
Investigador Júnioragradecimentos
Authors thank Xunta de Galicia, Universidad de Vigo and Ministerio de Educacion y Ciencia of Spanish government for financial support under the grants CN2012/227, 11VIA16 and FIS2011-29614.