The nature of protic ionic liquids in the gas phase revisited: Fourier transform ion cyclotron resonance mass spectrometry study of 1,1,3,3-tetramethylguanidinium chloride.
The sublimation/vaporization of the protic ionic liquid 1,1,3,3-tetramethylguanidinium chloride, [Htmg]Cl, was studied by Fourier transform ion cyclotron resonance mass spectrometry in the temperature range 298-488 K and under a reduced pressure of 3.2 x 10(-6) to 1.5 x 10(-5) Pa. The results show that no charged species are present in the vapor over the condensed phase. Furthermore, ion-molecule reaction studies found no evidence of neutral ion pairs in the gas phase. This indicates that the sublimation/vaporization of [Htmg]Cl conforms to the general mechanism postulated for the distillation of protic ionic liquids, which involves a proton transfer leading to the formation of the neutral acid and base precursors, in this case hydrogen chloride and 1,1,3,3-tetramethylguanidine.
Vitorino
Joana
J
Departamento de Química e Bioquímica, Faculdade de Ciências, Universidade de Lisboa, 1649-016 Lisboa, Portugal.
Leal
João P
JP
Minas da Piedade
Manuel E
ME
Canongia Lopes
José N
JN
Esperança
José M S S
JM
Rebelo
Luís Paulo N
LP