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R. Fareghi-Alamdari et al. / Journal of Molecular Liquids 227 (2017) 153–160
O
O
FDAIL
OR
OR
+
H2O
H2O
H2O
ROH
ROH
O
O
O
O
RO
OR
FDAIL
+
O
O
O
O
O
O
FDAIL
HO
RO
ROH
+
+
OH
OR
O
O
R = Methyl, Ethyl, n- Propyl, n-Butyl, 2- Ethylhexyl, 2- Methoxyethyl, Allyl
Scheme 1. Esterification of phthalic and maleic anhydrides and succinic acid with alcohols using synthesized FDAILs.
instrument using KBr or liquid film. Quantitative product analysis was
conducted by gas chromatography on Hewlett Packard HP-5890 instru-
ment equipped with HP-1 column (30 m long, 0.5 mm diameter), and
flame ionization detector (FDI), using N2 as carrier gas at a flow rate of
do this, 0.8 g IL-Br salt (2 mmol) was solved in acetonitrile. Then
0.5 mL chlorosulphonic acid (8 mmol) was dropped slowly at room
temperature. After the dropping was finished, the mixture was stirred
for 4 h at the same temperature. The reaction mixture was filtered to
get the yellow precipitate. It was washed with toluene three times
and dried under vacuum at 100 °C for 1 h, giving SFDAIL as a yellow
solid (yield: 97.5%). 1H NMR (500 MHz, DMSO-d6): δ (ppm) = 3.33
(s, 4H; CH2N), 3.47 (s, 6H; CH3), 4.04 (s, 4H; CH2OH), 5.33 (s, 2H;
SO3H), 7.06 (d, J = 5 Hz, 4H; CH _CH), 8.30 (s, 2H; NCHN). 13C NMR
(125 MHz, DMSO-d6): δ (ppm) = 36.19, 43.83, 48.27, 63.89, 123.88,
124.26, 137.79. FT-IR (KBr, ν/cm−1): 587.3, 782.5, 1019.1, 1251.7,
1458.7, 1584.9, 1709.1, 3160.1.
2 mL·min−1
.
2.2. Preparation of hydroxyl and sulfonic acid functionalized diacidic ionic
liquids
2.2.1. Preparation of 2,2-bis ((3-methylimidazolidin-1-yl) methyl) pro-
pane-1,3-diol bromide salt (IL-Br)
A mixture of 0.52 g 1-methylimidazole (6.25 mmol, 0.5 mL) and 0.65 g
2,2-bis (bromomethyl)-1,3-propanediol (2.5 mmol) was heated at 150 °C
for 8 h under magnetic stirring. After cooling to room temperature, the
obtained solid was washed three times with acetonitrile and the residue
was dried in an oven at 100 °C for 2 h, giving IL-Br as a white powder
(yield: 95.25%, melting point = 150 °C). 1H NMR (500 MHz, DMSO-d6):
δ (ppm) = 3.24 (s, 4H; CH2N), 3.84 (s, 6H; CH3), 4.31 (s, 4H; CH2OH),
4.72 (s, 2H; OH), 7.42 (dd, J = 10 Hz, J = 5 Hz, 4H; CH _CH), 8.72 (s,
2H; NCHN). 13C NMR (125 MHz, DMSO-d6): δ (ppm) = 35.94, 45.21,
48.58, 58.48, 123.72, 123.86, 137.38. FT-IR (KBr, ν/cm−1): 620.8, 770.7,
829.8, 1060.5, 1164.9, 1450.8, 1573.1, 1760.4, 1655.9, 2935.4, 3260.7.
2.2.3. Preparation of 3,3′-(2,2-bis (hydroxymethyl) propane-1,3-diyl) bis
(1-methyl-1H-imidazole-3-ium) hydrogen sulfate (HFDAIL)
The hydroxyl functionalized ionic liquid was prepared by anion ex-
change of IL-Br salt. 0.5 g (1.2 mmol) of IL-Br salt, obtained in the first
stage, was dissolved in methanol (30 mL) under stirring. After that the
system was slowly heated up to 60 °C in an oil bath. Then 0.13 mL sul-
furic acid (2.4 mmol) was dropped and stirred for 24 h. Upon comple-
tion of the reaction, the solvent was evaporated under vacuum. The
resultant material was washed with dichloromethane (3 × 5 mL) and
then dried under vacuum at 100 °C for 2 h to afford HFDAIL as yellow
viscous oil liquid at 95% yield. 1H NMR (500 MHz, DMSO-d6): δ
(ppm) = 3.20 (s, 4H; CH2N), 3.81 (s, 6H; CH3), 4.27 (s, 4H; CH2OH),
4.74 (s, 2H; OH), 7.39 (dd, J = 10 Hz, J = 5 Hz, 4H; CH _CH), 8.69 (s,
2.2.2. Preparation of 3,3′-(2,2-bis ((sulfoxy) methyl) propane-1,3-diyl) bis
(1-methyl-1H-imidazole-3-ium) bromide (SFDAIL)
The sulfonic acid functionalized ionic liquid, was prepared by nucle-
ophilic substitution reaction of IL-Br salt with chlorosulphonic acid. To
(SFDAIL): 3,3'- (2,2-Bis ((sulfoxy) methyl) propane-1,3-diyl) bis (1-methyl-1H-imidazole-3-ium) bromide
(HFDAIL): 3,3'- (2,2-Bis (hydroxymethyl) propane-1,3-diyl) bis (1-methyl-1H-imidazole-3-ium) hydrogen sulfate
Fig. 1. Structures of FDAILs used in this study.