Abstract
Trialkylimidazolium chlorozincate molten salts resulting from the combination of zinc chloride and 1-butyl-2,3-dimethylimidazolium chloride, [BMMI][Cl], have been prepared with a mole percent of ZnCl
2
,
R
(
R
=
n
ZnCl
2
n
ZnCl
2
+
n
[BMMI][Cl]
) equal to 0, 0.1, 0.25, 0.33, 0.5, 0.66, 0.75. Their analyses by DSC,
13
C,
1
H and
35
Cl solid state and solution NMR, and mass spectrometry (ESI, MS MS) are consistent with the presence of [BMMI][Cl] and [BMMI][ZnCl
3
] for
R
< 0.5; pure [BMMI][ZnCl
3
] for
R
= 0.5, and [BMMI][ZnCl
3
] with [BMMI][Zn
3
Cl
7
] for
R
> 0.5. Infrared spectra realized in the presence of pyridine show that the Lewis acidity of ZnCl
2
-[BMMI][Cl] increases with
R
. High temperature (110 °C)
13
C and
35
Cl NMR experiments on neat [BMMI][ZnCl
3
] (
R
= 0.5) evidenced that its structure varies with time from [BMMI][ZnCl
3
] to [BMMI Cl ZnCl
2
].
The structure of a series of [BMMI][Zn
x
Cl
2 +
x
] ionic liquids is shown to vary with time and temperature.