resumo
Within ionic liquids, fluorinated ionic liquids (FILs) present unique physico-chemical properties and potential applications in several fields. However, the melting point of these neoteric compounds is usually higher due to the presence of fluorine atoms. This drawback may be resolved by, for instance, mixing different FILs to create eutectic mixtures. In this work, binary mixtures of fluoro-containing and fluorinated ionic liquids were considered with the aim of decreasing their melting temperatures as well as understanding and characterizing these mixtures and their phase transitions. Five FILs were selected, allowing the investigation of four binary mixtures, each of them with a common ion. Their solid-liquid and solid-solid equilibria were studied by differential scanning calorimetry and the non-ideality of the mixtures was investigated. Overall, a variety of solid-liquid equilibria with systems exhibiting eutectic behavior, polymorphs with solid-solid phase transitions, and the formation of intermediate compounds and solid solutions were surprisingly found. In addition to these intriguing behaviours, novel FILs with lower melting temperatures were obtained by the formation of binary systems, thus enlarging the application range of FILs at lower temperatures.
palavras-chave
HEXAFLUOROPHOSPHATE SALTS; SURFACE-PROPERTIES; HEAT-CAPACITY; PHASE; BEHAVIOR; SIMULATIONS; MISCIBILITY; PREDICTION; CATIONS; ALKYL
categoria
Chemistry; Physics
autores
Teles, ARR; Correia, H; Maximo, GJ; Rebelo, LPN; Freire, MG; Pereiro, AB; Coutinhoa, JAP
nossos autores
Ana Rita Ribeiro Teles
Técnico Financeiro
Mara Guadalupe Freire Martins
Investigador CoordenadorGrupos
G4 - Materiais Renováveis e Economia Circular
G5 - Materiais Biomiméticos, Biológicos e Vivos
Projectos
CICECO - Aveiro Institute of Materials (UID/CTM/50011/2013)
Igy Technology: A Purication Platform using Ionic-Liquid-Based Aqueous Biphasic Systems (IGYPURTECH)
agradecimentos
The authors wish to acknowledge FCT/MCTES (Portugal) for the financial support through FCT Investigator 2014 of Ana B. Pereiro and through projects PTDC/QEQ-EPR/5841/2014 and UID/Multi/04551/2013. This work was developed in the scope of the project CICECO-Aveiro Institute of Materials POCI-01-0145-FEDER-007679, UID/CTM/50011/2013, financed by national funds through the FCT/MEC and when applicable co-financed by FEDER under the PT2020 Partnership Agreement. Mara G. Freire acknowledges the European Research Council (ERC) for the Starting Grant ERC-2013-StG-337753. Guilherme J. Maximo thanks FAPESP (2014/03992-7).