ABSTRACT

Two new amino acid ionic liquids (AAILs) [Cnmim][Thr] (n = 2, 4) (1-alkyl-3-methylimidazolium threonine salt) were prepared and characterized. The values of density, surface tension and refractive index of the ILs were measured at T = (288.15 to 328.15) K and the values of the molar surface Gibbs free energy, g, were calculated. Using the molar surface Gibbs free energy, the traditional Eotvos equation was improved to be a new Eotvos equation. It is found that the slope of the new Eotvos equation is the molar surface entropy of the ILs and the intercept is the molar surface enthalpy which is a temperature-independent constant. With the help of the refractive index and the molar surface Gibbs free energy, an equation to predict surface tension of the ILs was derived. Using this equation, predicted values of surface tension with the corresponding experimental ones are highly correlated and extremely similar. According to a new scale of polarity for ILs, the polarity of ionic liquids [Cnmim][Thr] (n = 2, 4) was estimated.

Compounds

#	Formula	Name
1	H2O	water
2	C10H19N3O3	3-ethyl-1-methyl-1H-imidazolium DL-threoninate
3	C12H23N3O3	3-butyl-1-methyl-1H-imidazolium DL-threoninate

Datasets

The table above is generated from the ThermoML associated json file (link above). POMD and RXND refer to PureOrMixture and Reaction Datasets. The compound numbers are included in properties, variables, and phases, if specificied; the numbers refer to the table of compounds on the left.
Type	Compound-#	Property	Variable	Constraint	Phase	Method	#Points
POMD	2	Mass density, kg/m3 ; Liquid	Temperature, K; Liquid	Pressure, kPa; Liquid	Liquid	Vibrating tube method	9
POMD	2	Refractive index (Na D-line) ; Liquid	Temperature, K; Liquid	Pressure, kPa; Liquid	Liquid	Standard Abbe refractometry	9
POMD	2	Surface tension liquid-gas, N/m ; Liquid	Temperature, K; Liquid		Liquid Air at 1 atmosphere	Maximal bubble pressure	9
POMD	3	Mass density, kg/m3 ; Liquid	Temperature, K; Liquid	Pressure, kPa; Liquid	Liquid	Vibrating tube method	9
POMD	3	Refractive index (Na D-line) ; Liquid	Temperature, K; Liquid	Pressure, kPa; Liquid	Liquid	Standard Abbe refractometry	9
POMD	3	Surface tension liquid-gas, N/m ; Liquid	Temperature, K; Liquid		Liquid Air at 1 atmosphere	Maximal bubble pressure	9
POMD	1 2	Mass density, kg/m3 ; Liquid	Temperature, K; Liquid Mass fraction - 1; Liquid	Pressure, kPa; Liquid	Liquid	Vibrating tube method	45
POMD	1 2	Refractive index (Na D-line) ; Liquid	Temperature, K; Liquid Mass fraction - 1; Liquid	Pressure, kPa; Liquid	Liquid	Standard Abbe refractometry	45
POMD	1 2	Surface tension liquid-gas, N/m ; Liquid	Temperature, K; Liquid Mass fraction - 1; Liquid		Liquid Air at 1 atmosphere	Maximal bubble pressure	45
POMD	1 3	Mass density, kg/m3 ; Liquid	Temperature, K; Liquid Mass fraction - 1; Liquid	Pressure, kPa; Liquid	Liquid	Vibrating tube method	45
POMD	1 3	Refractive index (Na D-line) ; Liquid	Temperature, K; Liquid Mass fraction - 1; Liquid	Pressure, kPa; Liquid	Liquid	Standard Abbe refractometry	45
POMD	1 3	Surface tension liquid-gas, N/m ; Liquid	Temperature, K; Liquid Mass fraction - 1; Liquid		Liquid Air at 1 atmosphere	Maximal bubble pressure	45

Thermodynamics Research Center / ThermoML | Journal of Chemical Thermodynamics

The molar surface Gibbs free energy and its application 2: Ionic liquids 1-alkyl-3-methylimidazolium threonine salts [Cnmim][Thr] (n = 2, 4) at T = (288.15 to 328.15) K

Tong, J.[Jing], Wang, L.-F.[Lin-Fu], Liu, D.-L.[Da-Liang], Chen, T.-F.[Teng-Fei], Tong, J.[Jian], Yang, J.-Z.[Jia-Zhen]

ABSTRACT