Molecular and ionic composition of saturated vapor over EMImNTf2 ionic liquid

Quantifying intermolecular interactions of ionic liquids using cohesive energy densities

“…electrons, was turned off, no ions were detected; it was concluded that the vapour phase of ILs is composed primarily of neutral species, not isolated ions [ 57 , 63 , 66 , 71 – 77 ]. More recently, using a specialist Knudsen effusion cell to produce the vapour of [C 2 C 1 Im][NTf 2 ] and electric fields to extract any overall charged ions in the vapour phase, [C] + , [C 2 A] + , [A] − and [CA 2 ] − were detected [ 87 , 91 ]. However, the amount of ions in the vapour phase was approximately 10 8 to 10 11 times lower than the amount of CA ion pairs [ 56 ], demonstrating the lack of significant amounts of overall charged ions in the vapour phase for [C 2 C 1 Im][NTf 2 ].…”

“…As noted in §4.2.2, for [C 2 C 1 Im][NTf 2 ] high temperature-capable thermal ion emission MS has been used to detect ionic vapour species with net overall charge, i.e. very small quantities of isolated [C] + and [A] − ions have been detected in the ionic vapour [ 87 , 91 ]. From measurements of the amount of [C] + and [A] − ions in the equilibrium ionic vapour at different temperatures the enthalpy of cation desorption from the bulk IL, Δ des H ([C] + ) and the enthalpy of anion desorption from the bulk IL, Δ des H ([A] − ) have been determined, respectively [ 87 , 91 ].…”

“…very small quantities of isolated [C] + and [A] − ions have been detected in the ionic vapour [ 87 , 91 ]. From measurements of the amount of [C] + and [A] − ions in the equilibrium ionic vapour at different temperatures the enthalpy of cation desorption from the bulk IL, Δ des H ([C] + ) and the enthalpy of anion desorption from the bulk IL, Δ des H ([A] − ) have been determined, respectively [ 87 , 91 ]. Therefore, experimental values for Δ des H ([C] + ) and Δ des H ([A] − ) (and therefore, Δ solv H ([C] + ) and Δ solv H ([A] − )) have now be obtained [ 87 , 91 ].…”

“…Experimental values for Δ des H ([C] + ) and Δ des H ([A] − ) can be obtained [ 87 , 91 ]. These measurements have been carried out in the range of T approximately 490 K. To obtain Δ des H ([C] + ) and Δ des H ([A] − ) at T = 298 K, an extrapolation is required.…”

“…For a wide range of ILs using positive mode mass spectrometry (MS) (with electron ionization, field ionization or photoionization) the parent cation, [C] + [57,63,66,[71][72][73][74][75][76][77][78][79][80][81][82][83][84][85][86][87][88][89], has been detected intact in the vapour phase (at 350 K < T < 700 K). In addition, the parent anion, [A] − [66,83,85], has been detected intact in the vapour phase using negative mode MS (with electron ionization or photoionization).…”