Aqueous solutions of [EMIM] 1,1,2,2-tetrafluoroethanesulfonate and [EMIM] trifluoromethanesulfonate: a thermodynamic study

Kód výsledku v IS VaVaI

<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F60461373%3A22340%2F18%3A43913458" target="_blank" >RIV/60461373:22340/18:43913458 - isvavai.cz</a>

Výsledek na webu

<a href="http://www.sciencedirect.com/science/article/pii/S002196141730455X" target="_blank" >http://www.sciencedirect.com/science/article/pii/S002196141730455X</a>

DOI - Digital Object Identifier

<a href="http://dx.doi.org/10.1016/j.jct.2017.12.019" target="_blank" >10.1016/j.jct.2017.12.019</a>

Jazyk výsledku

angličtina

Název v původním jazyce

Aqueous solutions of [EMIM] 1,1,2,2-tetrafluoroethanesulfonate and [EMIM] trifluoromethanesulfonate: a thermodynamic study

Popis výsledku v původním jazyce

While ionic liquids (ILs) based on a trifluoromethanesulfonate ([OTF]–) anion and their mixtures with other compounds have been relatively well explored, the information about structurally similar 1,1,2,2-tetrafluoroethanesulfonate-based ([TFES]–) ILs is either very scarce or, as in the case of their mixtures with water, totally lacking. We herein thus present a broad thermodynamic characterization of aqueous solutions of [EMIM][TFES] and [EMIM][OTF], with the study of aqueous solutions of the latter serving as a benchmark. First, the peculiar solid-liquid phase transition behavior of the neat [EMIM][TFES] was examined and its density was determined over a temperature range encompassing both the subcooled and the stable liquid. For the aqueous solutions of the two ILs, we performed extensive measurements of water activity (a_w) across the entire composition range, mixing enthalpy and density specifically in the highly dilute IL region, and the solution freezing temperatures at water mole fractions greater than 0.6. The ample a_w data were fitted (i) by a two-step procedure and (ii) simultaneously with the excess enthalpy data using an extended NRTL-type model. The latter approach to the global description of energetics of the systems is preferred for its handiness in practical calculations. We duly proved its reliability in extrapolation and/or prediction against experimental data on various properties, among others, SLE. The analysis of volumetric data by the Redlich-Meyer equation allowed us to obtain accurate values of infinite dilution partial molar volumes of the ILs and revealed the nature of their hydration as rather hydrophobic. The solution behavior of the systems studied was found to be essentially non-ideal: their small S-shaped excess Gibbs energy actually results from the compensation of their large positive excess enthalpy and entropy.

Název v anglickém jazyce

Aqueous solutions of [EMIM] 1,1,2,2-tetrafluoroethanesulfonate and [EMIM] trifluoromethanesulfonate: a thermodynamic study

Popis výsledku anglicky

While ionic liquids (ILs) based on a trifluoromethanesulfonate ([OTF]–) anion and their mixtures with other compounds have been relatively well explored, the information about structurally similar 1,1,2,2-tetrafluoroethanesulfonate-based ([TFES]–) ILs is either very scarce or, as in the case of their mixtures with water, totally lacking. We herein thus present a broad thermodynamic characterization of aqueous solutions of [EMIM][TFES] and [EMIM][OTF], with the study of aqueous solutions of the latter serving as a benchmark. First, the peculiar solid-liquid phase transition behavior of the neat [EMIM][TFES] was examined and its density was determined over a temperature range encompassing both the subcooled and the stable liquid. For the aqueous solutions of the two ILs, we performed extensive measurements of water activity (a_w) across the entire composition range, mixing enthalpy and density specifically in the highly dilute IL region, and the solution freezing temperatures at water mole fractions greater than 0.6. The ample a_w data were fitted (i) by a two-step procedure and (ii) simultaneously with the excess enthalpy data using an extended NRTL-type model. The latter approach to the global description of energetics of the systems is preferred for its handiness in practical calculations. We duly proved its reliability in extrapolation and/or prediction against experimental data on various properties, among others, SLE. The analysis of volumetric data by the Redlich-Meyer equation allowed us to obtain accurate values of infinite dilution partial molar volumes of the ILs and revealed the nature of their hydration as rather hydrophobic. The solution behavior of the systems studied was found to be essentially non-ideal: their small S-shaped excess Gibbs energy actually results from the compensation of their large positive excess enthalpy and entropy.

Druh

J_imp - Článek v periodiku v databázi Web of Science

CEP obor

—

OECD FORD obor

10403 - Physical chemistry

Projekt

—

Návaznosti

I - Institucionalni podpora na dlouhodoby koncepcni rozvoj vyzkumne organizace

Rok uplatnění

2018

Kód důvěrnosti údajů

S - Úplné a pravdivé údaje o projektu nepodléhají ochraně podle zvláštních právních předpisů

Název periodika

Journal of Chemical Thermodynamics

ISSN

0021-9614

e-ISSN

—

Svazek periodika

119

Číslo periodika v rámci svazku

April

Stát vydavatele periodika

GB - Spojené království Velké Británie a Severního Irska

Počet stran výsledku

13

Strana od-do

114-126

Kód UT WoS článku

000425191700012

EID výsledku v databázi Scopus

2-s2.0-85042513014