Thermodynamics Research Center / ThermoML | Thermochimica Acta

Thermal Stability and Crystallization Behavior of Imidazolium Halide Ionic Liquids

Efimova, A.[Anastasia], Hubrig, G.[Grit], Schmidt, P.[Peer]
Thermochim. Acta 2013, 573, 162-9
ABSTRACT
The 1-Butyl-3-methylimidazolium halide ionic liquids are stable up to temperatures of 246(1) ([BMIm]Cl), 260(1) ([BMIm]Br), and 238(1) deg C ([BMIm]I). The thermal decomposition proceeds in thermogravimetric measurements with a total mass loss of 100 %. Using evolved gas analysis (EGA) a complete degradation of [BMIm]X ionic liquids under formation of characteristic fragments CH3+, NH+, C4Hn+ , and CH3X+ (X = Cl, Br, I) has been observed. [BMIm]Cl shows enantiotropic polymorphism with a phase transition temperature at 30(1) deg C and melts at 74(1) deg C ([delta]Hfus = 18 +- 0.5 kJ.mol.1). Spontaneous re-crystallization and reversible phase transition have been found for cooling of the substance. [BMIm]Br melts at 78(1) deg C ([delta]Hfus = 29 +- 0.5 kJ.mol.1). The re-crystallization fails and thus a glassy solid is formed. The glass transition temperature is about .65deg C, the cold crystallization occurs between .30 .20 deg C. The application of nucleation agents does not interfere the glassy state. [BMIm]I undergoes a solidification without crystallization. The melting effect for the amorphous substance arise at -70(5) deg C with [delta]Hfus = 0.4 +- 0.2 kJ.mol.1.
Compounds
# Formula Name
1 C8H15ClN2 1-butyl-3-methylimidazolium chloride
2 C8H15BrN2 1-butyl-3-methylimidazolium bromide
3 C8H15IN2 1-butyl-3-methylimidazolium iodide
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 2
  • Crystal 2
  • Crystal 1
  • Air at 1 atmosphere
  • DTA
  • 1
  • POMD
  • 1
  • Molar enthalpy of transition or fusion, kJ/mol ; Crystal 2
  • Crystal 2
  • Crystal 1
  • Air at 1 atmosphere
  • DSC
  • 1
  • POMD
  • 1
  • Normal melting temperature, K ; Crystal
  • Crystal
  • Liquid
  • Air at 1 atmosphere
  • DTA
  • 1
  • POMD
  • 1
  • Molar enthalpy of transition or fusion, kJ/mol ; Crystal
  • Crystal
  • Liquid
  • Air at 1 atmosphere
  • DSC
  • 1
  • POMD
  • 2
  • Normal melting temperature, K ; Crystal
  • Crystal
  • Liquid
  • Air at 1 atmosphere
  • DTA
  • 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 ; Glass
  • Glass
  • Liquid
  • Air at 1 atmosphere
  • DTA
  • 1