Novel oxidation of hydrogen sulfide by dimethyl sulfoxide in presence of β-cyclodextrin

Article abstract of DOI:10.14233/ajchem.2014.17827

Dimethyl sulfoxide is used as an oxidizing agent to oxidize hydrogen sulfide to solid sulfur at room temperatures and normal pressures, in which, β-cyelodextrin plays an important role in this reaction. in this work, when GC-MS, SEM and FTIR spectroscopic

Full text of DOI:10.14233/ajchem.2014.17827

Asian Journal of Chemistry; Vol. 26, No. 20 (2014), 7040-7042
ASIAN JOURNAL OF CHEMISTRY
http://dx.doi.org/10.14233/ajchem.2014.17827
Novel Oxidation of Hydrogen Sulfide by Dimethyl Sulfoxide in Presence of β-Cyclodextrin
*
XIAOXIA YANG, JIANBIN ZHANG , YAN CHANG and QIANG LI
College of Chemical Engineering, Inner Mongolia University of Technology, Huhhot 010051, P.R. China
*Corresponding author: Tel/Fax: +86 471 6575722; E-mail: tadzhang@pku.edu.cn
Received: 16 April 2014;
Accepted: 30 May 2014;
Published online: 25 September 2014;
AJC-16062
Dimethyl sulfoxide is used as an oxidizing agent to oxidize hydrogen sulfide to solid sulfur at room temperatures and normal pressures,
in which, β-cyclodextrin plays an important role in this reaction. In this work, when GC-MS, SEM and FTIR spectroscopic techniques
were used for inspection of spectral changes of β-cyclodextrin, dimethyl sulfoxide solution with increasing H2S concentration, the results
suggest that H2S was oxidated by dimethyl sulfoxide in the presence of β-cyclodextrin and dimethyl sulfide, water, and sulfur can be
identified. The results of this work can be used to provide important reaction mechanism of H2S with dimethyl sulfoxide in the presence
of β-cyclodextrin with potential industrial application of β-cyclodextrin-dimethyl sulfoxide solution.
Keywords: Dimethyl sulfoxide, Hydrogen sulfide, β-Cyclodextrin, Dimethyl sulfide.
of the oxidation of dithiols depends on slow addition to an
excess of dimethyl sulfoxide to avoid polymerization. Thiols
(RSH, ArCH2SH, ArSH) can be oxidized to disulfides (R-S-
S-R, etc.) by dimethyl sulfoxide. Reactivity depends upon the
acidity of the thiol (ArSH >ArCH2SH > RSH).Aromatic thiols
are oxidized spontaneously at room temperatures, whereas
higher temperatures are required for oxidation of aliphatic
thiols7,8. The oxidation of disulfides to sulfonic acids by dimethyl
sulfoxide has been described. Unfortunately, several similar
sulfides did not react appreciably with dimethyl sulfoxide
under these conditions and attempts to catalyze the reactions
with acid were unsuccessful. Especially, H2S is statisfactory
oxidation is not accomplished without modification of the
procedure.
INTRODUCTION
The versatility of dimethyl sulfoxide as a solvent medium
in organic reactions has received widespread attention in recent
several decades1,2. In some cases, the ability of dimethyl sulfo-
xide to act as an oxidation in the course of reaction has been
recognized. Dimethyl sulfoxide was found to oxidize n-propyl,
n-butyl and tetramethylene sulfides to the corresponding
sulfoxides in yield of 59, 55 and 58 %, respectively. The condi-
tions employed involved heating the sulfide with a 50 % molar
excess of dimethyl sulfoxide at 160-175 °C for several hours3.
Kornblum and collaborators4 had reported the successful
oxidation of several phenacyl halides with dimethyl sulfoxide.
Subsequent addition of the carbonyl component and appro-
priate reaction temperature, time and product isolation complete
the process. Researchers had reported the some reactions of
S(-2) with dimethyl sulfoxide in the presence of catalysts. The
needed changes are an increase in the amount of halogen or
hydrogen halide catalyst to about twice the number of moles
of L-cystine and a significantly lower reaction temperature.
The combinations DL-cysteic acid-dimethyl sulfoxide and DL-
homocysteic acid with both dimethyl sulfoxide and tetra-
methylene sulfoxide were also checked. The corresponding
molecular complexes were obtained; though, with DL-homo-
cysteic acid, these were syrups from which it appeared that
the compounds slowly crystallized5. The explanation for
formation of these compounds would appear to lie in the ability
of the oxygen of sulfoxides such as dimethyl sulfoxide and
tetramethylene sulfoxide to serve as a proton acceptor6. Success
Removal of hydrogen sulfide (H2S) from gases is required
for reasons of health, safety and corrosion during transmission
and distribution and to prevent pollution with sulfur dioxide
(SO2) upon combustion of the gases. Several different types
of processes are in use for treating "sour" gases containing the
acid component of H2S. Possible gas-treating applications are
many and varied and the selection of a truly optimum treatment
method is a complex process, such as incineration, adsorption
or chemical scrubbing. Because of the favorable absorption
and desorption properties for acid gases in industrial processes,
organic solvents have become the subject of increasing interests
in recent years9-13. Wei and his coworkers have paid great atten-
tion to the alcohol system to remove acidic gases for several
years14-17. In the present work, we tried to develop a new system
for the absorption of H2S by using dimethyl sulfoxide and a

Vol. 26, No. 20 (2014)
Novel Oxidation of Hydrogen Sulfide by Dimethyl Sulfoxide in Presence of β-Cyclodextrin 7041
novel reaction of H2S with dimethyl sulfoxide was observed in
the presence of β-cyclodextrin.
In the hope of finding a mild enough oxidizing agent we
attempted the following oxygen reaction, using dimethyl
sulfoxide as an oxygen donor. The present procedure is attrac-
tive not only for its simplicity and general applicability, but
also because dimethyl sulfoxide plays a double role of oxidizing
agent and solvent. Futhermore, β-cyclodextrin has been used
as a cyclic component in the construction of supramolecular
architectures because of well-defined ring structure. We wish
herein to report the novel oxidation of H2S by dimethyl sulfo-
xide in the presence of β-cyclodextrin. In this work, it is known
that H2S can be oxidized by using dimethyl sulfoxide in the
presence of β-cyclodextrin. In addition the by-product of the
reaction, dimethyl sulfide, water and sulfur were identified by
various spectroscopic techniques.
Fig. 1. Photograph of the formed sulfur
EXPERIMENTAL
A scanning electron microscope (SEM) is used to study
the surface morphology of the precipitate, which reveals that
sulfur ether can be identified (Fig. 2a,b). In Fig. 1a, it illustrates
that the precipitate is inclined trapezium shape. It is also found
that the size of the crystal is about 800 µm. Fig. 1b shows energy
spectrum pattern of the precipitate film. It is identified that
the precipitate is elemental sulfur.
Analytical grade dimethyl sulfoxide and β-cyclodextrin
are purchased from Beijing Reagent Company. Capillary
column for GC-MS/MS on QMS with an Rtx-5 MS capillary
column (30 m × 0.25 mm i.d; 0.25 µm film thickness) was
used. Helium (purity 99.999 %) was the carrier gas with a
constant flow of 1 mL/min. The inlet temperature was main-
tained at 200 °C. The initial temperature was 40 °C, held for
10 min; ramped at 25 °C/min up to 220 °C and held for 5 min.
Data were collected using GC/MS analysis software.A Hitachi
(Japan) S-3400N Scanning Electron Microscope (SEM) was
used. FTIR spectra were recorded on a Bruker VECTOR22
FTIR spectrometer with a resolution of 1 cm-1 at 298 K in the
range from 4000 to 400 cm-1. The spectrometer possesses auto-
align energy optimization and a dynamically aligned inter-
ferometer and fitted with a constringent BaF2 pellet for the
measurement of aqueous solution, an OPUS/IR operator and
IR source. A base line correction was made for the spectra
that were recorded in air; and then 15 mL solution was used
on the FTIR spectrometer in every one of measurements and
the thin layer of samples are less than typically 2 µm thickness.
Measurements: 0.8000 g of β-cyclodextrin is dissolved
in 100 mL dimethyl sulfoxide and mix well-distributed, at
room temperatures and normal pressures, accessing with H2S,
while the solution gradually becomes yellow. The solution still
presents yellow and rather with some kind of yellow preci-
pitation, after about 24 h. On the other hand, there is no yellow
precipitate if dimethyl sulfoxide is bubbled into H2S without
the presence of β-cyclodextrin.
(a)
(b)
RESULTS AND DISCUSSION
The contrast test was performed in the absence of β-cyclo-
dextrin. In the contrast test, no sulfur was found after 2 days.
A photograph shows the precipitated sulfur for 24 h in
the presence of H2S (Fig. 1) in the presence of β-cyclodextrin.
After in the presence of H2S the color changes of β-cyclo-
dextrin dimethyl sulfoxide solution from colorless to yellow
could be due to a reaction of dimethyl sulfoxide with H2S. To
confirm the reaction process the β-cyclodextrin dimethyl
sulfoxide solutions in the presence of H2S were analyzed by
SEM, FTIR and GC-MS techniques.
0
2
4
6
8
10
12
14
keV
Fig. 2. (a) SEM micrograph of the surface; (b) energy spectrum pattern of
the precipitate film
Liquid supernatant is analyzed by GC-MS method and
results are shown in Fig. 3a,b, which undergoes an intra-
molecular hydrogen transfer to give the observed carbonyl
product plus dimethyl sulfide.

7042 Yang et al.
Asian J. Chem.
1.67
100
(a)
95
90
85
80
75
70
65
60
55
50
45
40
35
30
25
20
15
11.05
11.22
12.38
14.12 14.24
10.87
10.77
10.47
5.60
5.85
5.97
9.91
9.55
8.73
8.48
6.12
8.04
6.42
6.63
6.86
1198
2096
1662
1.54
1.39
10
5
3442
2.77
3.60
4
4.38
5
0
0
1
2
3
6
7
8
9
10
11
12
13 14
15 16
Time (min)
4000
3500
3000
2500
2000
1500
1000
62.98
Wavelength (cm–1)
100
95
90
85
80
75
70
65
60
55
50
45
40
35
30
25
20
15
10
5
Fig. 4. FTIR spectra of dimethyl sulfoxide (top), β-cyclodextrin dimethyl
sulfoxide solution (middle) and β-cyclodextrin dimethyl sulfoxide
solution in the presence of H2S bottom
(b)
62.13
ACKNOWLEDGEMENTS
This work was supported by foundation of the program
for new century excellent talents in university (NCET-12-
1017), the Program for Grassland Excellent Talents of Inner
Mongolia Autonomous Region, the Inner Mengolia Science
& Technology Plan, the program for young talents of science
and technology in universities of inner mongolia autonomous
region (NJYT-12-B13) and the natural science foundation of
Inner Mongolia Autonomous Region (2011BS0601, China).
61.17
59.13
60
47.11
45.07
35.10
63.96
73.97
19.08
27.16
77.02 93.99 104.01 123.92 137.10 146.59 163.80 181.39
80 100 120 140 160 180
m/z
0
20
40
Fig. 3. (a) GC-MS selected ion plots of liquid supernatant; (b) GC-MS/
MS spectra of liquid supernatant
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This paper provides a novel reaction of dimethyl sulfoxide
with H2S in the presence of β-cyclodextrin, while it converts
H2S to solid sulfur under a condition of room temperature and
normal atmospheric pressure.