ABSTRACT

The speed of sound in the protic ionic liquids (PILs) N-methyl-2-hydroxyethylammonium butyrate (m2HEAB) and N-methyl-2-hydroxyethylammonium pentanoate (m2HEAP) was measured at atmospheric pressure, and over the range of temperatures T = (293.15 to 343.15) K. The speed of sound and density of aqueous mixtures of the ionic liquid were also determined throughout the entire concentration range, within the (298.15 to 333.15) K temperature range and at atmospheric pressure. The excess molar volume, excess isentropic compressibility, excess speed of sound, apparent molar volume and apparent molar isentropic compressibility were calculated from the experimental density and speed of sound values. Furthermore, all the properties were correlated with selected analytical functions. The apparent molar volume of aqueous PILs was analysed by Pitzer Simonson theory. The speed of sound of the PILs was predicted with the Wu et al. model and the molar compressibility of the same PILs and their aqueous mixtures were calculated from Wada' s model. The results demonstrate that the molar compressibility calculated from Wada' s model is almost a linear function of mole fraction and can be considered as temperature independent for a fixed mole fraction over the whole composition range. The results were analysed and discussed from the structural changes point of view in aqueous medium.

Compounds

#	Formula	Name
1	C8H19NO3	2-hydroxy-N-methylethanaminium pentanoate
2	C7H17NO3	N-methyl-2-hydroxyethylammonium butanoate
3	H2O	water

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	1	Speed of sound, m/s ; Liquid	Temperature, K; Liquid	Pressure, kPa; Liquid Frequency, MHz; Liquid	Liquid	Single path-length method	11
POMD	2	Speed of sound, m/s ; Liquid	Temperature, K; Liquid	Pressure, kPa; Liquid Frequency, MHz; Liquid	Liquid	Single path-length method	11
POMD	3 2	Mass density, kg/m3 ; Liquid	Temperature, K; Liquid Mole fraction - 2; Liquid	Pressure, kPa; Liquid	Liquid	Vibrating tube method	80
POMD	3 2	Speed of sound, m/s ; Liquid	Temperature, K; Liquid Mole fraction - 2; Liquid	Pressure, kPa; Liquid Frequency, MHz; Liquid	Liquid	Single path-length method	80
POMD	3 1	Mass density, kg/m3 ; Liquid	Temperature, K; Liquid Mole fraction - 1; Liquid	Pressure, kPa; Liquid	Liquid	Vibrating tube method	80
POMD	3 1	Speed of sound, m/s ; Liquid	Temperature, K; Liquid Mole fraction - 1; Liquid	Pressure, kPa; Liquid Frequency, MHz; Liquid	Liquid	Single path-length method	80

Thermodynamics Research Center / ThermoML | Journal of Chemical Thermodynamics

Volumetric and acoustical properties of aqueous mixtures of N-methyl-2-hydroxyethylammonium butyrate and N-methyl-2-hydroxyethylammonium pentanoate at T = (298.15 to 333.15) K

Li, Y.[Yang], Figueiredo, E. J. P.[Eduardo J. P.], Santos, M. J.[Mario J.], Santos, J. B. [Jaime B.], Talavera-Prieto, N. M. C.[Nieves M. C.], Carvalho, P. J.[Pedro J.], Ferreira, A. G. M.[Abel G. M.], Mattedi, S.[Silvana]

ABSTRACT