Thermodynamics Research Center, ThermoML : Journal of Chemical and Engineering Data

Structure-Property Relationship for 1-Isopropyl-3-methylimidazolium- and 1-tert-Butyl-3-methylimidazolium-Based Ionic Liquids: Thermal Properties, Densities, Viscosities, and Quantum Chemical Calculations

Endo, T.[Takatsugu], Sakaguchi, K.[Kei], Higashihara, K.[Kazuki], Kimura, Y.[Yoshifumi]
J. Chem. Eng. Data 2019, 64, 12, 5857-5868
ABSTRACT
We systematically analyzed the thermal phase behavior (phase change and thermal decomposition temperatures), densities, and viscosities of 1-isopropyl-3-methylimidazolium ([iC3mim]+)- and 1-tert-butyl-3-methylimidazolium ([tC4mim]+)-based ionic liquids (ILs) with [I]-, [PF6]-, bis(fluorosulfonyl)imide, bis(trifluoromethylsulfonyl)imide, and bis(pentafluoroethylsulfonyl)imide counterions. The results were compared to those for ILs based on the corresponding linear alkyl imidazolium cations (1-methyl-3-propylimidazolium and 1-butyl-3-methylimidazolium). Our results revealed that the melting points of the branched ILs are always higher than those of the linear ILs. The densities of [tC4mim]X are higher than those of the linear ILs, which is somewhat counterintuitive when considering previously reported molecular liquid data. Using the van der Waals volume data estimated in this work, the fractional free volumes of the ILs were estimated. This revealed that the linear and branched ILs have largely similar void space values in the liquid state. The viscosities of [tC4mim]X are higher than those of the linear ILs, while those of [iC3mim]X are comparable. To better understand the structure-property relationship for the branched ILs, density functional theory calculations were performed for the ions in the gas phase. The structure-property relationship of the branched ILs is discussed in terms of bulkiness, conformational entropy, structural symmetry, and cation-anion interaction changes.
Compounds
# Formula Name
1 C7H13IN2 1-methyl-3-(1-methylethyl)imidazolium iodide
2 C7H13F6N2P 1-methyl-3-(1-methylethyl)imidazolium hexafluorophosphate
3 C7H13F2N3O4S2 1-isopropyl-3-methylimidazolium bis(fluorosulfonyl)imide
4 C9H13F6N3O4S2 1-methyl-3-(1-methylethyl)imidazolium bis[(trifluoromethyl)sulfonyl]imide
5 C11H13F10N3O4S2 1-isopropyl-3-methylimidazolium bis(pentafluoroethylsulfonyl)imide
6 C8H15IN2 1-tert-butyl-3-methylimidazolium iodide
7 C8H15F6N2P 1-tert-butyl-3-methylimidazolium hexafluorophosphate
8 C8H15F2N3O4S2 1-tert-butyl-3-methylimidazolium bis(fluorosulfonyl)imide
9 C10H15F6N3O4S2 1-tert-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide
10 C12H15F10N3O4S2 1-tert-butyl-3-methylimidazolium bis(pentafluoroethylsulfonyl)imide
11 C7H13F2N3O4S2 1-methyl-3-propylimidazolium bis(fluorosulfonyl)imide
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
  • Triple point temperature, K ; Crystal
  • Crystal
  • Liquid
  • Air at 1 atmosphere
  • DSC
  • 1
  • POMD
  • 1
  • Molar enthalpy of transition or fusion, kJ/mol ; Crystal
  • Crystal
  • Liquid
  • Air at 1 atmosphere
  • DSC
  • 1
  • POMD
  • 2
  • Triple point temperature, K ; Crystal
  • Crystal
  • Liquid
  • Air at 1 atmosphere
  • DSC
  • 1
  • POMD
  • 2
  • Molar enthalpy of transition or fusion, kJ/mol ; Crystal
  • Crystal
  • Liquid
  • Air at 1 atmosphere
  • DSC
  • 1
  • POMD
  • 3
  • Triple point temperature, K ; Crystal
  • Crystal
  • Liquid
  • Air at 1 atmosphere
  • DSC
  • 1
  • POMD
  • 3
  • Molar enthalpy of transition or fusion, kJ/mol ; Crystal
  • Crystal
  • Liquid
  • Air at 1 atmosphere
  • DSC
  • 1
  • POMD
  • 3
  • Mass density, kg/m3 ; Liquid
  • Temperature, K; Liquid
  • Pressure, kPa; Liquid
  • Liquid
  • Vibrating tube method
  • 8
  • POMD
  • 3
  • Viscosity, Pa*s ; Liquid
  • Temperature, K; Liquid
  • Pressure, kPa; Liquid
  • Liquid
  • Cone and plate viscometry
  • 8
  • POMD
  • 4
  • Triple point temperature, K ; Crystal
  • Crystal
  • Liquid
  • Air at 1 atmosphere
  • DSC
  • 1
  • POMD
  • 4
  • Molar enthalpy of transition or fusion, kJ/mol ; Crystal
  • Crystal
  • Liquid
  • Air at 1 atmosphere
  • DSC
  • 1
  • POMD
  • 4
  • Mass density, kg/m3 ; Liquid
  • Temperature, K; Liquid
  • Pressure, kPa; Liquid
  • Liquid
  • Vibrating tube method
  • 8
  • POMD
  • 4
  • Viscosity, Pa*s ; Liquid
  • Temperature, K; Liquid
  • Pressure, kPa; Liquid
  • Liquid
  • Cone and plate viscometry
  • 8
  • POMD
  • 5
  • Triple point temperature, K ; Glass
  • Glass
  • Liquid
  • Air at 1 atmosphere
  • DSC
  • 1
  • POMD
  • 5
  • Mass density, kg/m3 ; Liquid
  • Temperature, K; Liquid
  • Pressure, kPa; Liquid
  • Liquid
  • Vibrating tube method
  • 8
  • POMD
  • 5
  • Viscosity, Pa*s ; Liquid
  • Temperature, K; Liquid
  • Pressure, kPa; Liquid
  • Liquid
  • Cone and plate viscometry
  • 8
  • POMD
  • 6
  • Triple point temperature, K ; Crystal
  • Crystal
  • Liquid
  • Air at 1 atmosphere
  • DSC
  • 1
  • POMD
  • 6
  • Molar enthalpy of transition or fusion, kJ/mol ; Crystal
  • Crystal
  • Liquid
  • Air at 1 atmosphere
  • DSC
  • 1
  • POMD
  • 7
  • Triple point temperature, K ; Crystal
  • Crystal
  • Liquid
  • Air at 1 atmosphere
  • DSC
  • 1
  • POMD
  • 7
  • Molar enthalpy of transition or fusion, kJ/mol ; Crystal
  • Crystal
  • Liquid
  • Air at 1 atmosphere
  • DSC
  • 1
  • POMD
  • 8
  • Triple point temperature, K ; Crystal
  • Crystal
  • Liquid
  • Air at 1 atmosphere
  • DSC
  • 1
  • POMD
  • 8
  • Molar enthalpy of transition or fusion, kJ/mol ; Crystal
  • Crystal
  • Liquid
  • Air at 1 atmosphere
  • DSC
  • 1
  • POMD
  • 8
  • Viscosity, Pa*s ; Liquid
  • Temperature, K; Liquid
  • Pressure, kPa; Liquid
  • Liquid
  • Cone and plate viscometry
  • 4
  • POMD
  • 9
  • Triple point temperature, K ; Crystal
  • Crystal
  • Liquid
  • Air at 1 atmosphere
  • DSC
  • 1
  • POMD
  • 9
  • Molar enthalpy of transition or fusion, kJ/mol ; Crystal
  • Crystal
  • Liquid
  • Air at 1 atmosphere
  • DSC
  • 1
  • POMD
  • 9
  • Mass density, kg/m3 ; Liquid
  • Temperature, K; Liquid
  • Pressure, kPa; Liquid
  • Liquid
  • Vibrating tube method
  • 8
  • POMD
  • 9
  • Viscosity, Pa*s ; Liquid
  • Temperature, K; Liquid
  • Pressure, kPa; Liquid
  • Liquid
  • Cone and plate viscometry
  • 8
  • POMD
  • 10
  • Triple point temperature, K ; Crystal
  • Crystal
  • Liquid
  • Air at 1 atmosphere
  • DSC
  • 1
  • POMD
  • 10
  • Molar enthalpy of transition or fusion, kJ/mol ; Crystal
  • Crystal
  • Liquid
  • Air at 1 atmosphere
  • DSC
  • 1
  • POMD
  • 10
  • Triple point temperature, K ; Glass
  • Glass
  • Liquid
  • Air at 1 atmosphere
  • DSC
  • 1
  • POMD
  • 10
  • Mass density, kg/m3 ; Liquid
  • Temperature, K; Liquid
  • Pressure, kPa; Liquid
  • Liquid
  • Vibrating tube method
  • 8
  • POMD
  • 10
  • Viscosity, Pa*s ; Liquid
  • Temperature, K; Liquid
  • Pressure, kPa; Liquid
  • Liquid
  • Cone and plate viscometry
  • 8
  • POMD
  • 11
  • Mass density, kg/m3 ; Liquid
  • Temperature, K; Liquid
  • Pressure, kPa; Liquid
  • Liquid
  • Vibrating tube method
  • 8
  • POMD
  • 11
  • Viscosity, Pa*s ; Liquid
  • Temperature, K; Liquid
  • Pressure, kPa; Liquid
  • Liquid
  • Cone and plate viscometry
  • 8