Synthesis and characterization of 1-(hydroxyethyl)-3-methylimidazolium sulfate and chloride ionic liquids

Article abstract of DOI:10.1016/j.molstruc.2016.02.017

We have used the imidazole as a starting compound for the preparation of a new ionic liquid 1-(hydroxyethyl)-3-methylimidazolium sulfate, with a yield of 98% in the two-steps synthesis. This new ionic liquid at room temperature exhibits a greater chemical activity. For the first step, we change the previous synthetic route using 2-chloroethanol as starting material, and with 1-methylimidazole to prepare the 1-(hydroxyethyl)-3-methylimidazolium chloride [EtOHMIM⁺][Cl^?]. In the second stage, we have exchanged the anion Cl^? with HSO₄ ^?. The ionic liquid shows reasonably high conductivity and thermal stability up to 340?°C. Our samples are characterized by ¹H NMR, ¹³C NMR and FT-IR. The physical characteristics of the ionic liquid, such as solvation capacity were studied using a thermo-gravimetric Analyzer (NETZSCH DSC 204 F1) in the range of 40–400?°C. The results show that the ILs may be used as polyelectrolyte for electrochemical applications.

Full text of DOI:10.1016/j.molstruc.2016.02.017

Journal of Molecular Structure 1113 (2016) 182e190
Contents lists available at ScienceDirect
Journal of Molecular Structure
journal homepage: http://www.elsevier.com/locate/molstruc
Synthesis and characterization of 1-(hydroxyethyl)-3-
methylimidazolium sulfate and chloride ionic liquids
Yassine Chaker a, , Hocine Ilikti , Mansour Debdab , Taqiyeddine Moumene ,
b
a
b
b
b
c
d
e
El Habib Belarbi , Anne Wadouachi , Ouissam Abbas , Brahim Khelifa ,
e, *
Serge Bresson
a
Laboratoire de Chimie et d’Electrochimie des Complexes M ꢀe talliques, l’Universit ꢀe des Sciences et de la Technologie Mohamed Boudiaf, El Mnaouar, BP 1505,
Bir El Djir 31000 Algeria
b
Laboratoire de Synth ꢁe se et Catalyse LSCT, Univ Tiaret, Route de Zaaroura, BP 78 RP 14000 Tiaret, Algeria
c
Laboratoire de Glycochimie, des Antimicrobiens et des Agroressources CNRS FRE 3517, Institut de Chimie de Picardie CNRS FR 3085, Universit ꢀe Picardie
t
Jules Verne, 33 rue S Leu 80039 Amiens cedex, France
d
Centre Wallon de Recherche Agronomique, CRA-W, B a^ timent Maurice Henseval, chauss ꢀe e de Namur, 24, 5030 Gembloux, Belgium
e
t
Laboratoire de Physique des Syst ꢁe mes Complexes, Universit ꢀe Picardie Jules Verne, 33 rue S Leu 80039 Amiens cedex, France
a r t i c l e i n f o
a b s t r a c t
Article history:
Received 25 October 2015
Received in revised form
We have used the imidazole as a starting compound for the preparation of a new ionic liquid 1-
(
hydroxyethyl)-3-methylimidazolium sulfate, with a yield of 98% in the two-steps synthesis. This new
ionic liquid at room temperature exhibits a greater chemical activity. For the first step, we change the
12 January 2016
previous synthetic route using 2-chloroethanol as starting material, and with 1-methylimidazole to
Accepted 4 February 2016
Available online xxx
þ
ꢀ
prepare the 1-(hydroxyethyl)-3-methylimidazolium chloride [EtOHMIM ][Cl ]. In the second stage, we
ꢀ
ꢀ
have exchanged the anion Cl with HSO
4
. The ionic liquid shows reasonably high conductivity and
ꢁ
1
13
thermal stability up to 340 C. Our samples are characterized by H NMR, C NMR and FT-IR. The physical
characteristics of the ionic liquid, such as solvation capacity were studied using a thermo-gravimetric
Analyzer (NETZSCH DSC 204 F1) in the range of 40e400 C. The results show that the ILs may be
Keywords:
Ionic liquids
NMR
ꢁ
FTIR
used as polyelectrolyte for electrochemical applications.
DSC
© 2016 Elsevier B.V. All rights reserved.
ATG
DTG
1. Introduction
chemical synthesis, separation science and electrochemistry. They
can be used also as dopping elements in polymers [6,7].
Ionic liquids (ILs) are salts comprising ions, which exist in the
liquid state at ambient temperatures. They have many unique
physical and chemical properties such as negligible vapor pressure,
thermal and chemical stability, high ionic conductivity and excel-
lent solubility of many substances [1]. Several studies have been
reported on the use of IL without reaction solvents [2], the sepa-
rating extraction solvents [3] and electrolyte materials [4,5]. ILs
properties can be modified by substitution of cations and anions
with special functional groups. Functionalized ILs which are
incorporated with one or more functional groups have special
structures and a lot of interests in many research fields like
In this work, we investigate the effect of the anions on the
vibrational behavior of our samples and the changing in the ther-
mal properties as melting, crystallization, glass and degradation
þ
ꢀ
temperatures by comparison between [EtOHMIM ][Cl ] and
þ
ꢀ
4
[EtOHMIM ][HSO
]. The last one exhibits higher characteristic
temperatures.
2. Materials and methods
2.1. Reagents and materials
The reagents used in this study are: 1-methylimidazol, 2-
chloroethanol, acetonitrile, diethyl ether (99% pure.) used without
*
Corresponding author.
E-mail address: sergebresson@yahoo.fr (S. Bresson).
any further purification.
http://dx.doi.org/10.1016/j.molstruc.2016.02.017
022-2860/© 2016 Elsevier B.V. All rights reserved.
0

Y. Chaker et al. / Journal of Molecular Structure 1113 (2016) 182e190
183
1
20°C
OH
H SO , MeCN
OH
N
N
2
4
OH
N
N
N
N
+
Cl
N
N
OH
2
4h
Cl
Cl
r.t, 24h
HSO4
Fig. 1. Amine quaternization reaction.
Fig. 2. Anion exchange reaction.
2
.2. NMR, spectroscopy analysis
1H and 13C NMR spectra were recorded on a Bruker Biospin
Avance III spectrometer equipped with a 5 mm TXI probe at 600
-
-
cooling from ꢀ120 ꢁC to ꢀ100 ꢁC leaving the sample at this
temperature for 5 min
ꢁ
ꢁ
heating from ꢀ100 C to 200 C
and 150.93 MHz, respectively. Chemical shifts ( ) are given in ppm
d
The measures of the TGA, and the DTG analysis leaking gas
and referenced to the internal signal solvent D O.
2
during the experiment made with a NETZSCH STA 449C (TGA-DSC)
ꢁ
ꢁ
(
20 Ce1500 C) apparatus coupled to a mass spectrometer for
2
.2.1. Synthesis and characterization of 1-(hydroxyethyl)-3-
ꢁ
þ
ꢀ
analyzing the gas, with a heating rate of 5 C/min in a temperature
range of 20 Ce400 C under Argon.
methylimidazolium chloride [EtOHMIM ] [Cl ] [8e11].
ꢁ
ꢁ
A mixture of 2-chloroethanol (0.67 mL, 10 mmol) and 1-
ꢁ
methylimidazole (1.1 g, 10 mmol) was heated for 24 h at 120 C.
3
3
3
. Results and discussion
The crude product, which crystallized upon cooling, was finely
crushed, washed with Et
pressure for 10 h [10](Fig. 1).
2
O (3 ꢂ 80 mL), and dried under reduced
.1. NMR results
ꢁ
Pale yellow powder; yield: 1.8 g (94%); mp 55e58 C.
þ
.1.1. 1-(hydroxyethyl)-3-methylimidazolium chloride [EtOHMIM ]
ꢀ
[
Cl ]
2
.2.2. Synthesis and characterization of 1-(hydroxyethyl)-3-
1
þ
ꢀ
NMR H:(600 MHz, D O):
d
¼ 8.78 (s, 1H, H-2), 7.54 (s, 1H, H-4 or
), 3.96 (t,
2
methylimidazolium sulfate [EtOHMIM ][HSO
An equimolar mixture of
4
] [12,13].
H-5), 7.49 (s, 1H, H-4 or H-5), 4.34 (t, 2H, J ¼ 4.9 Hz, NCH
2
1-(hydroxy eꢀ thyl)-3-
2
H, J ¼ 4.9 Hz, CH
2
O), 3.93 (s, 3H, NCH
NMR C (150.93 MHz, D O):
), 59.8 (CH O), 51.5 (NCH ), 35.7 (NCH
3
).
methylimidazolium chloride (0.01 mol/1.5256 g) and sulfuric acid
SO (0.01 mol/0.5355 ml) dissolved in 30 ml acetonitrile was
13
2
d
¼ 136.4 (C-2),123.6,122.4 (C-4, C-
H
2
4
5
2
2
3
). NMR spectra are pre-
stirred vigourously at room temperature (initial liquid homoge-
neous medium) for 24 h (Fig. 2).
sented on Fig. 3.
Then, the product obtained was ground, washed with diethyl
þ
ꢁ
3.1.2. 1-(hydroxyethyl)-3-methylimidazolium sulfate [EtOHMIM ]
ether (3 ꢂ 80 ml) and filtered on sintered glass of porosity N 0.4.
-
[
HSO
NMR 1H: (600 MHz, D
HSO-
), 7.54 (s, 1H, H-4 or H-5), 7.48 (s, 1H, H-4 or H-5), 4.52 (t, 2H,
J ¼ 5 Hz, NCH OH) 3.90 (s, 3H, NCH ).
¼ 136.6 (C-2),123.6,122.6 (C-4, C-
), 35.8 (NCH ). NMR spectra are pre-
4
]
The product was finally dried under reduced pressure for 10 h to
remove traces of solvent.
2
O):
d
¼ 8.78 (s, 1H, H-2), 8.76 (s, 1H,
4
2
), 4.33 (t, 2H, J ¼ 5 Hz, CH
2
3
2
.3. FTIR/ATR measurements
13
NMR C (150.93 MHz, D
), 66.1 (CH O), 51.5 (NCH
sented on Fig. 4.
2
O): d
5
2
2
3
The measurements were realized in the Walloon Agricultural
Research Center (CRA-W) Belgium.
Fourier Transform mid-infrared All attenuated total reflectance
FTIR/ATR) measurements were acquired on a Bruker Vertex II-70
(
3.2. The comparison between FTIR/ATR spectra of ionic liquids: 1-
þ
ꢀ
RAMSpectrometer (Bruker Analytical, Madison, WI) operating
with a Golden Gate diamond ATR accessory TM (Specac Ltd, Slough,
(hydroxyethyl)-3-methylimidazolium chloride [EtOHMIM ][Cl ]
þ
and 1-(hydroxyethyl)-3-methylimidazolium sulfate [EtOHMIM ]
ꢀ
1
-
United Kingdom). FTIR/ATR spectra [4000e600 cm
]
were
[HSO4 ]
ꢀ
1
collected with Resolution 1 cm by co-adding 64 scans for each
spectrum. The OPUS Software 6.0 for Windows was used for the
management of the instrument.
FTIR/ATR spectra [4000e600 cmꢀ1] of the two ionic liquids are
illustrated in Fig. 5. Both spectra were normalized on the mode at
ꢀ1
6
20 cm . The assignments of the observed modes in this spectral
2
.4. DSC measurements
region are reported in Table 1. All reported peak values were based
on the maximum peak height of the unfitted spectra. Curve fitting
and fitted frequency values labeled * were performed as per Bres-
son et al. [14]. On the IR spectra (see Fig. 5), we distinguish three
well defined spectral regions: 3500e2600, 1800e1300 and
Characterization by DSC was carried out with a Differential
calorimetry system (NETZSCH DSC 204 F1) with a speed of heating
and cooling 5 C/min, by performing two heating and cooling cycles
to remove traces of water and solvent in a temperature range of
ꢁ
ꢀ1
þ
ꢀ
1300e600 cm . For [EtOHMIM ] [Cl ], the modes in the three
ꢁ
ꢁ
(
ꢀ100 Ce200 C) under Argon. The experimental procedure is as
spectral regions seem to have a homogenous intensity, whereas for
þ
ꢀ
4
follows:
[EtOHMIM ] [HSO
] the modes seem more intense in the
1300e600 spectral range.
-
-
cooling from ꢀ25 ꢁC to ꢀ100 ꢁC, leaving the sample at this
ꢀ
1
temperature for 5 min
3.2.1. Region 1300e600 cm
In this spectral zone (Fig. 6) where both spectra were
ꢁ
ꢁ
heating from ꢀ100 C to 120 C

184
Y. Chaker et al. / Journal of Molecular Structure 1113 (2016) 182e190
(a)
(b)
Fig. 3. 1H NMR (600 MHz) (a) and 13C NMR (150.93 MHz) (b) [EtOHMIM ][Cl ].
þ
ꢀ

Y. Chaker et al. / Journal of Molecular Structure 1113 (2016) 182e190
185
(
a)
(
b)
Fig. 4. 1H NMR (600 MHz) (a) and 13C NMR (150.93 MHz) (b) [EtOHMIM ][HSO
þ
ꢀ
4
].

186
Y. Chaker et al. / Journal of Molecular Structure 1113 (2016) 182e190
(
1500e1400) also seems to be influenced by the choice of the anion
ꢀ1
[
EtOHMIM+] [Cl-]
in a less important way. In the spectral zone 1800e1500 cm , we
observe a shift in frequency of the vibrational mode attributed to
the ring C]C and HeCeH stretching modes. The shift is from
1
1
ꢀ
1
ꢀ
ꢀ1
571 cm
for the anion Cl to 1578 cm
with a shoulder at
ꢀ
1
ꢀ
ꢀ1
ꢀ
570 cm for HSO
4
and conversely from 1645 cm for HSO to an
4
ꢀ1
ꢀ
unresolved doublet in 1677 and 1692 cm for the Cl anion [19].
We also observe the presence of overtones CeH stretching modes
ꢀ1
ꢀ
4
with a shift in frequency between both anions: 1743 cm for HSO
against 1750 cm for Cl .
ꢀ
1
ꢀ
[EtOHMIM+] [HSO4-]
ꢀ
1
3.2.3. Region 3500e2400 cm
In this spectral region (Fig. 8) where spectra were normalized on
ꢀ
1
þ
ꢀ
ꢀ1
the mode at 3098 cm for [EtOHMIM ] [Cl ] and 3086 cm for
þ
ꢀ
[
EtOHMIM ] [HSO
4
], we observe the affected modes of alkyl
stretchable region alcohol OH. We observe that these spectra each
ꢀ
ꢀ
4
4
000
3500
3000
2500
2000
1500
1000
anion has its peculiarity: for the Cl anion and for HSO
peaks with
ꢀ
1
-1
high density in the region 3200e2850 cm , the spectral range
Wavenumber (cm )
ꢀ1
4
000e2800 cm is very sensitive in FTIR/ATR depending on the
þ
ꢀ
þ
ꢀ
4
]in the spectral
Fig. 5. FTIR/ATR spectra of [EtOHMIM ] [Cl ] and[EtOHMIM ][ HSO
range 3500e600 cm
choice of the anion and cation coupled and can serve as signature of
a particular ionic liquid. In the case of anion 2, the (CeH) stretching
modes are the most intense in this spectral range: 3038, 3055,
ꢀ
1
.
ꢀ ꢀ1 ꢀ
1
3
098 cm and 3142 cm for the anion Cl , and 3086, 3116 and
ꢀ
1
ꢀ
4
normalized on the mode at 1175 cmꢀ1, we observe numerous
differences of vibrational behavior according to the choice of the
anion. For the Cl anion, the spectral zone 700e600 cm is more
intense than for [EtOHMIM ] [ HSO ] with the ascendancy of 4
modes in 620, 652, 686 and 706 cm while for the only HSO
anion the mode in 620 cm seems to be intense. The modes at
20, 652, 686 cm are assigned to (NeH) wagging and CH
CN stretching whereas the mode at 706 cm
CH (N)/CH (N)CN bending [15,16]. Conversely in the spectral
2 3
3154 cm
for the anion HSO [15,16].
ꢀ
ꢀ1
4. Thermal properties
þ
ꢀ
ꢀ
4
þ
ꢀ
þ
1
ꢀ
The DSC thermograms for [EtOHMIM ] [Cl ] and [EtOHMIM ][
4
ꢀ
ꢀ
1
HSO ] are shown in Fig. 9 and the thermogravimetric analysis
4
ꢀ
1
curves (TGA), the derivative thermogravimetric curves (DTG) and
the mass spectrometry curves are shown in Fig. 10. By its turn, the
thermal gravimetric parameters extracted from these curves are
presented in Table 2.
6
3
(N)
ꢀ1
corresponds in
ꢀ
1
þ
zone 950e700 cm , the vibrational behavior for [EtOHMIM ]
ꢀ
[
HSO
4
] seems to present more modes with two doublets and
ꢀ
1
ꢀ1
4.1. DSC thermogram
shoulder (735, 754, 771 cm and 850, 873, 903 cm ) while for
EtOHMIM ] [Cl ] we observe only two modes in 796 and
68 cm assigned to ring HCCH bending and CH asymmetric
rocking modes respectively. The strong peak at 903 cm
observed for [EtOHMIM ] [HSO ] is assigned to (NeS) stretching
mode [15,16]. All assignments of the observed modes in Fig. 5 are
presented in the Table 1. We notice the presence of new intense
modes between both samples at 1017 and 1224 cm assigned to
the HSO
vibrational modes [17]. The presence of the HSO
transform a single peak in to a double one for the mode
175 cm
156, 1175 cm for the HSO
(N)CN stretching mode [15,16]. Conversely, the doublet
observed for the Cl anion at 1062 and 1074 cm appears as one
peak for the HSO
CeO) stretching mode [18]. We thus notice that this spectral
þ
ꢀ
[
8
ꢀ
1
While heating from lower temperature we observe a glass
2
ꢁ
ꢁ
ꢀ1
transitions Tg ¼ ꢀ20 C, then an endothermic peak onset at 64 C
þ
ꢀ
was observed in the heating phase corresponding to the melting
point of ([EtOHMIM ][Cl ]) (Fig. 9a), (Table 2).
For ([EtOHMIM ][HSO4 ])., we observe the same phenomenon
but with different values of temperature: a glass transitions
4
þ
ꢀ
þ
ꢀ
ꢀ
1
ꢁ
ꢁ
ꢀ
Tg ¼ ꢀ62 C and an endothermic peak onset at 153 C observed in
4
anion (SeO) stretching mode and the doubling of
ꢀ
the heating phase corresponding to the melting point of
4
anion seems to
þ
ꢀ
(
[EtOHMIM ][HSO4 ]) (Fig. 9b) (Table 2).
.2. Thermal stability
From the TGA and DTG curves in (Fig. 10a) [EtOHMIM ][Cl ] is
steady below 67 C and the degradation began at 67 C in two
stages between 20 C and 400 C. The first stage begins at almost
7 C with a mass loss of 2.30% and ends at a temperature of 253
ꢀ
1
ꢀ
1
1
CH
observed for the Cl anion: we notice the doublet
ꢀ
1
ꢀ
4
4
anion, assigned to ring CH
2
(N)/
3
þ
ꢀ
ꢀ
ꢀ1
ꢀ
ꢀ1
ꢁ
ꢁ
4
anion centered at 1068 cm
assigned to
ꢁ
ꢁ
(
ꢁ
ꢁꢁ
6
C
zone seems very sensitive to the interactions with anions and can
serve as witness of the influence of the one or the other anion in
the vibrational behavior with the imidazolium.
corresponding to the release of OH identified gas from the mass
ꢁ
spectrometry curve. The second stage begins at 253 C and ends at
ꢁ
about 334 C with a loss of 89.46% corresponding to the release of
CH
(Fig. 10b).
For [EtOHMIM ][HSO
(Fig. 10c) show that [EtOHMIM ][HSO
began to degrade from 155 C in three stages, leaving a reddish
3
and OH identified gas from the mass spectrometry curve
ꢀ
1
3
.2.2. Region 1800e1300 cm
þ
ꢀ
4
] sample, the TGA and DTG thermograms
In this spectral zone (Fig. 7) where spectra were normalized on
the mode at 1571 cm for [EtOHMIM ] [Cl ] and 1578 cm for
], we observe spectra with more modes for the
anion than for the Cl anion. We note that the CeC stretching
mode at 1347 cm is transformed for the HSO
336 cm modes [15,16]. The spectral zone of the CH bending
ꢀ
1
þ
ꢀ
ꢀ1
þ
ꢀ
ꢁ
4
] is steady below 155 C and
þ
ꢀ
ꢁ
[EtOHMIM ] [HSO
4
ꢀ
ꢀ
ꢁ
HSO
4
residue of 19% from the initial mass at 400 C. The first stage begins
ꢀ1
ꢀ
ꢁ
4
anion to 1353 and
at almost 155 C with a mass loss of 12.82% and ends at a tem-
ꢀ
1
ꢁ
1
2
perature of 274 C corresponding to the release of H
2
O identified

Y. Chaker et al. / Journal of Molecular Structure 1113 (2016) 182e190
187
Table 1
Observed FTIR/ATR bands and their assignment of chloride 1-(hydroxyethyl)-3-methylimidazolium and sulfate 1-(hydroxyethyl) -3-methylimidazolium (Vw ¼ very
weak,w ¼ weak, m ¼ medium, s ¼ strong, sh ¼ shoulder, Str ¼ stretch, d ¼ deformation, bend ¼ bending deformation,
u
¼ wagging,
r
¼ rocking, s ¼ symmetric,
as ¼ antisymmetric).
þ
ꢀ
[EtOHMIM ][HSO-
þ
[
EtOHMIM ][Cl ]
4
]
Assignment
Refs
6
05 (m)
u
u
u
u
(NeH)/CH
(NeH)/CH
(NeH)/CH
3
3
3
(N) CN Str
(N) CN Str
(N) CN Str
(NeH)
[15,16]
[15,16]
[15,16]
[15,16]
[15,16]
[15,16]
[15,16]
[15,16]
[15,16]
[15,16]
[15,16]
[17]
620 (s)
652 (s)
687 (s)
705 (m)
620 (s)
660 (w)
(CeH) þ
u
700(m)
CH
2
(N)/CH
3
(N)CN bend
735* (sh)
753 (m)
771 (s)
u
u
n
(CeH)
(CeH)
(NeC)
7
8
9
97 (s)
Ring HCCH as bend
850* (sh)
r
r
n
r
n
as(CH
as(CH
(NeS)
as(CH
(NeS)
2
)
)
68 (s)
873 (s)
2
903 (s)
42 (vw)
2
)
[15,16]
[17]
[17]
9
1
68 (vw)
017 (s)
SeOH
1
1
1
1
1
1
1
1
027* (sh)
038 (m)
062 (m)
074 (s)
100 (vw)
119 (vw)
175 (m)
198 (m)
CH
CH
n (CeO)
CC Str
CC Str
CC Str
3
N Str/CH
N Str/CH
2
N Str
N Str
[15,16]
[15,16]
[18]
[17]
[17]
3
2
1068 (s)
1090* (sh)
1108 (w)
1175 (m)
1198 (m)
[15,16]
[15,16]
[15,16]
[17]
[15,16]
[15,16]
[15,16]
[18]
[15,16]
[15,16]
[15,16]
[15,16]
[15,16]
[15,16]
[15,16]
[19]
Ring as Str CH
Ring s CH (N) and CH
(SeO)
Ring ip as str str
2
(N) and CH
3
(N)CN Str/CC
(N)CN Str
2
3
1
224 (m)
1256 (m)
336 (m)
n
1254 (w)
1
n
n
d
r
r
r
d
d
d
(CeC)
(CeC)
(CH) e
(NeH)
(NeH)
(NeH)
(CH
(CH
(CH
1347 (m)
1371 (w)
1388* (sh)
1353 (m)
1372* (sh)
1390 (m)
s
d (CH3)
1412* (sh)
1
1
424 (m)
446 (m)
1431* (sh)
1438 (m)
2
)/CCH HCH as bend
2
)/CCH HCH as bend
2
)/CCH HCH as bend
1462* (sh)
1
1
481 (w)
571 (s)
1480 (m)
1570* (sh)
2 3
as Str CH (N)/CH (N)CN Str
1
1
578 (s)
645 (w)
Ring C]C str, N]CeN str
Ring C]C str, N]CeN str
Ring C]C str, N]CeN str
Ring C]C str, N]CeN str
Overtone ¼ CeH str
[19]
[19]
[19]
[19]
1
1
1
2
2
2
2
2
677 (w)
692 (w)
750 (w)
481(w)
600 (vw)
673 (w)
714 (vw)
830 (w)
1742 (w)
2470 (vw)
n
n
n
n
n
n
n
n
(C]C)
[15,16]
[15,16]
[15,16]
[15,16]
[15,16]
[15,16]
[15,16]
[15,16]
[15,16]
[15,16]
[15,16]
[15,16]
[15,16]
[15,16]
[15,16]
[15,16]
[15,16]
[15,16]
[15,16]
[17,18]
s
(CH
s
(CH
s
(CH
s
(CH
s
(CH
2
)
2
)
2
)
2
)
2
)
2842 (w)
2870 (m)
2930 (w)
2954 (m)
2966 (m)
2865 (w)
2907(m)
as(CH
as(CH
2
)
)
2
3
CH (N)HCH as Str
n
n
n
n
n
(CeH)
(CeH)
(CeH)
(CeH)
(CeH)
2975 (w)
2
3
3
3
3
991* (sh)
038 (m)
055 (m)
095 (m)
098(s)
2990 (w)
3030 (w)
3048* (sh)
3086 (m)
¼CeH Str
¼CeH Str
¼CeH Str
¼CeH Str
¼CeH Str
3116 (m)
3142 (m)
3
3
154 (m)
225* (sh)
n (OeH)
[17,18]

188
Y. Chaker et al. / Journal of Molecular Structure 1113 (2016) 182e190
[EtOHMIM+] [Cl-]
[EtOHMIM+] [Cl-]
[EtOHMIM+] [HSO4-]
[EtOHMIM+] [HSO4-]
3500
3400
3300
3200
3100
3000
2900
2800
2700
-
1
1
300
1200
1100
1000
900
800
700
600
Wavenumber (cm )
-1
Wavenumber (cm )
þ
ꢀ
þ
ꢀ
4
] in the spectral
Fig. 8. FTIR/ATR spectra of [EtOHMIM ] [Cl ] and [EtOHMIM ][ HSO
ꢀ
1
range 3500e2400 cm
.
þ
ꢀ
þ
ꢀ
4
]in the spectral
Fig. 6. FTIR/ATR spectra of [EtOHMIM ] [Cl ] and [EtOHMIM ][ HSO
range 1300e600 cm
ꢀ
1
.
(
a)
exo
0,6
gas from the mass spectrometry curve (Fig. 10d). The second stage
ꢁ
ꢁ
begins at 274 C and ends at about 342 C with a loss of 6.24%
corresponding to the release of CH and OH identified gas from the
3
0
0
0
0
,5
,4
,3
,2
mass spectrometry curve, and the third stage between 342 and
+
-
[
EtOHMIM ][CL ]
ꢁ
4
00 C with a loss of 61.94%.
5
. Conclusion
þ
In this study, we synthesized a new Ionic liquid [EtOHMIM ]
ꢀ
[
HSO
4
] which was characterized by RMN, FTIR/ATR and DSC. The
0,1
0,0
obtained compound shows interesting thermal properties. The
results of vibrational spectroscopy and DSC was compared with
þ
those obtained on the same intermediate compound [EtOHMIM ]
ꢀ
-0,1
[
Cl ] who differs only by the type of anion. The anion seems to play
an important influence in the thermal stability of the compound as
-
100
-50
0
50
100
150
200
well as on its vibrational behavior.
o
temperature/ c
(b)
0
,02 exo
+
-
[
EtOHMIM ][HSO4 ]
[
EtOHMIM+] [Cl-]
0,00
0,02
0,04
0,06
0,08
0,10
-
-
-
-
-
[
EtOHMIM+] [HSO4-]
1800 1750 1700 1650 1600 1550 1500 1450 1400 1350 1300
-100
-50
0
50
100
150
200
-
1
o
Wavenumber (cm )
temperature/ c
þ
ꢀ
þ
ꢀ
þ
ꢀ
þ
ꢀ
Fig. 7. FTIR/ATR spectra of [EtOHMIM ][Cl ] and [EtOHMIM ][ HSO
4
] in the spectral
Fig. 9. DSC thermogram of ionic liquid [EtOHMIM ][Cl ] (a) and [EtOHMIM ][HSO4 ]
ꢀ
1
ꢁ ꢁ
(b) from 100 C to 200 C.
range 1800e1300 cm
.

þ
ꢀ
þ
ꢀ
ꢁ
ꢁ
þ
ꢀ
þ
ꢀ
Fig. 10. TGA and DTG of ionic liquid [EtOHMIM ][Cl ] (a) and [EtOHMIM ][HSO
4
] (c) (20 Ce400 C) and mass spectrometric diagram of gas escaped from ionic liquid [EtOHMIM ][Cl ] (b) and [EtOHMIM ][HSO ] (d).
4

190
Y. Chaker et al. / Journal of Molecular Structure 1113 (2016) 182e190
Table 2
ꢀ
4
Thermal properties of [EtOHMIM ] [Cl ] and [EtOHMIM ][HSO ].
of the C2 position in interionic interactions of imidazolium based ionic liquids:
a vibrational and NMR spectroscopic study, Phys. Chem. Chem. Phys. 12 (42)
þ
ꢀ
þ
(2010) 14153e14161.
ꢁ
ꢁ
ꢁ
ꢁ
T
Ionic liquids
Tg ( C)
Tf ( C)
Td ( C)
Td
( C)
[9] J.M. Obliosca, S.D. Arco, M.H. Huang, Synthesis and optical properties of 1-
alkyl-3-methylimidazolium lauryl sulfate ionic liquids, J. Fluoresc. 17 (6)
þ
þ
ꢀ
[
[
EtOHMIM ] [Cl ]
ꢀ20
ꢀ62
64
153
67
155
305
343
(2007) 613e618.
ꢀ
4
]
EtOHMIM ] [HSO
[
10] M. Debdab, F. Mongin, J.P. Bazureau, Ionic-liquid-supported synthesis of
amines and derivatives, Synthesis 23 (2006) 4046e4052.
[
11] S. Zhang, X. Qi, X. Ma, L. Lu, Q. Zhang, Y. Deng, Investigation of cation-anion
interaction in 1-(2-hydroxyethyl)-3-methylimidazolium-based ion pairs by
density functional theory calculations and experiments, J. Phys. Org. Chem. 25
Acknowledgment
(2012) 248e257.
[
12] J.-C. Legeay, J.J.V. Eynde, J.P. Bazureau, Ionic liquid phase technology sup-
ported the three component synthesis of Hantzsch 1, 4-dihydropyridines and
Biginelli 3, 4-dihydropyrimidin-2 (1H)-ones under microwave dielectric
heating, Tetrahedron, 61 (52) (2005) 12386e12397.
13] A. Arfan et, J.P. Bazureau, Efficient combination of recyclable task specific ionic
liquid and microwave dielectric heating for the synthesis of lipophilic esters,
Org. process Res. Dev. 9 (6) (2005) 743e748.
We would like to thank Quentin Arnould, technician of Walloon
Agricultural Research Centre (CRA-W), who participated to FTIR/
ATR measurements and the ATRST-DGRSDT for the financial
support.
[
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