Please do not adjust margins
RSC Advances
Page 2 of 8
DOI: 10.1039/C5RA09166G
ARTICLE
Journal Name
Various alkyl bromides were purchased from aladdin chemistry and refluxed for 3 h. Afterwards, cooled mixture was poured
Co., Ltd (Shanghai, China). The Pd (II) stock solution (2.0 × into water (900 mL), and the oil layer was separated by
10ꢀ4 mol Lꢀ1) was prepared by dissolving metal chlorides in HCl extracted twice with petroleum ether. Combined organic phase
solution and PdCl2 was from Sinopharm Chemical Reagent was washed with water and dried over sodium sulfate. After
Beijing Co., Ltd. (Beijing, China). Toluene was used as diluent removing the petroleum ether solvent by distilling under
for these sulfoxides. Distilled water was used to prepare the vacuum, colorless liquids were obtained in all cases with high
aqueous solutions in all experiments. The above reactants were purity and good yield (81ꢀ94%).
of analytical grade and were used without further purification.
Synthesis of Sulfoxides. Thioethers (0.05 mol) and 30%
aqueous H2O2 (5.1 mL) were mixed and stirred at 60oC
overnight. After the reaction mixture was then extracted twice
with petroleum ether, the combined organic phase was washed
2.2 Analytical techniques
The Pd (II) concentration in the aqueous phase was determined with water and dried over sodium sulfate. The petroleum ether
by an atomic absorption spectrophotometer (3150, Precision & solvent was then removed by distilling under vacuum. The
Scientific Instrument Shanghai Co., Ltd., Shanghai, China). IR residue was purified by column chromatography on silica gel
spectra were obtained on an IR spectrophotometer VERTEX 70 with petroleum ether to ethyl acetate as the eluent, and the
1
FTꢀIR (Bruker Optics). H NMR spectra were performed on a solvent was removed by rotary evaporation. After drying under
Bruker Avance 300 (300 MHz) spectrometer with CDCl3 as high vacuum for 2 h, colorless liquids were obtained with good
solvents and tetramethylsilane (TMS) as the internal standard. yield (78ꢀ83%).
HRMS spectra were recorded on a QꢀTOF6510 spectrograph
(Agilent).
The synthetic sulfoxides were characterized as follows.
Isooctyl n amyl sulfoxide. Yield, 81%; colorless liquid; H
1
ꢀ
NMR: δ 0.89ꢀ0.95 (m, 9H), δ 1.30ꢀ1.71 (m, 12H), δ 1.73ꢀ1.83
(p, 2H), δ 1.89ꢀ1.93 (m, 1H), δ 2.43ꢀ2.51 (m, 1H), δ 2.57ꢀ2.73
(m, 3H); IR (KBr): 2959, 2927, 2865, 1738, 1459, 1378, 1033,
2.3 General extraction procedure
Equal volumes of the aqueous and organic phases were added 827, 730 cmꢀ1; HRMS: calcd for [M + H]+ C13H28OS:
to a glass tube and then equilibrated mechanically in an orbital 233.1934; found: 233.1943.
shaker for 40 min (the equilibrium reached in 20 minutes).
Isooctyl 1ꢀmethylbutyl sulfoxide. Yield, 80%; colorless
1
Afterwards, the organic phase and the aqueous phase were liquid; H NMR: δ 0.88ꢀ0.99 (m, 9H), δ 1.21ꢀ1.61 (m, 14H), δ
separated quickly with a centrifuge at 2000 rpm for 5 min. The 1.77ꢀ1.81 (m, 1H), δ 1.89ꢀ1.98 (m, 1H), δ 2.39ꢀ2.47 (m, 1H), δ
metal concentration of aqueous phase was determined by 2.52ꢀ2.64 (m, 2H); IR (KBr): 2959, 2929, 2871, 1464, 1403,
atomic absorption spectrophotometer at 247.6 nm. The metal 1383, 1035, 827, 727 cmꢀ1; HRMS: calcd for [M + H]+
concentration of the organic phase was calculated by mass C13H28OS: 233.1934; found: 233.1933.
balances. Unless stated specially, all experiments were carried
out at 298 ± 1 K.
Isooctyl 2ꢀmethylbutyl sulfoxide. Yield, 78%; colorless
1
liquid; H NMR: δ 0.89ꢀ0.96 (m, 9H), δ 1.06ꢀ1.10 (t, 3H), δ
1.27ꢀ1.65 (m, 10H), δ 1.91ꢀ1.94 (m, 2H), δ 2.27ꢀ2.35 (dd, 1H),
δ 2.46ꢀ2.76 (m, 3H); IR (KBr): 2961, 2929, 2874, 1737, 1461,
1406, 1379, 1034, 774, 729, 695 cmꢀ1; HRMS: calcd for [M +
2.4 Synthesis procedure
Alkanethiols, Thioethers and sulfoxides were synthesized by H]+ C13H28OS: 233.1934; found: 233.1934.
previously reported methods with slight modifications.20ꢀ24
Isooctyl 3 methylbutyl sulfoxide. Yield, 83%; colorless
ꢀ
Synthesis of Alkanethiols. The corresponding alkyl bromide liquid; 1H NMR: δ 0.89ꢀ0.98 (m, 12H), δ 1.26ꢀ1.75 (m, 11H), δ
(0.20 mol) and thiourea (0.21 mol) were added to ethanol (120 1.89ꢀ1.94 (m, 1H), δ 2.44ꢀ2.52 (m, 1H), δ 2.63ꢀ2.73 (m, 3H);
mL), the reaction mixture was refluxed and stirred for 7 h. IR (KBr): 2958, 2928, 2872, 1464, 1408, 1382, 1034, 880, 727,
NaOH solution (2.5 mol Lꢀ1, 120 mL) was then added into the 640 cmꢀ1; HRMS: calcd for [M + H]+ C13H28OS: 233.1934;
mixture and refluxed for another 2 h. After that, the reaction found: 233.1910.
solution appeared as two layers, the aqueous layer was
separated and acidified by diluted HCl solution and then
extracted twice by petroleum ether. The combined organic
phase was washed with water and dried over sodium sulfate.
3. Results and discussion
3.1 Influence of extraction time
The petroleum ether solvent was removed by distilling under
vacuum. Colorless liquids were obtained in all cases with high
purity and good yield (61ꢀ82%).
The effect of contact time on the Pd(II) extraction was studied
firstly. With other fixed extraction parameters: organic phase of
Synthesis of Thioethers. NaOH (0.10 mol) was dissolved in
0.1 mol Lꢀ1 isooctyl nꢀamyl sulfoxide (OASO), aqueous phase
absolute ethanol (100 mL) with heating and stirring. After the
of 2.0 × 10ꢀ4 mol Lꢀ1 Pd(II) in 0.1 mol Lꢀ1 HCl solution, Rw:o
=
dissolution was completed and its temperature dropped to about
25oC, the corresponding thiol (0.11 mol) was added dropwise in
ten minutes, followed by adding the alkyl bromide (0.10 mol) at
the same temperature. Precipitation of sodium chloride
appeared almost immediately, and the mixture was then stirred
1. The contact time ranged from 5 to 30 min. Due to the
constant percentage extraction, the extraction equilibrium of
Pd(II) was found reached in 20 min, even to 30 min. Hence, 40
2 | J. Name., 2012, 00, 1-3
This journal is © The Royal Society of Chemistry 20xx
Please do not adjust margins
Huang, Yixian
