Surfactant-encapsulated high-nuclear polyoxometalate complexes for catalytic oxidative desulfurization of model oil

Article abstract of DOI:10.1016/j.ica.2016.02.065

Two novel surfactant-encapsulated high-nuclear polyoxometalates catalysts (DODA)₂₀[(HPMo₆O₂₁)₄(O₂CCH₂CO₂)₆]·27H₂O and (DODA)₁₀[(HPMo₆O₂₁)₂(C₂O₄)₃]·11H₂O have been prepared and characterized by TG, FT-IR,¹H NMR and UV-Vis. They were used for the oxidative desulfurization of model oil containing sulfur compounds such as dibenzothiophene (DBT), 4,6-dimethyldibenzothiophene (4,6-DMDBT), benzothiophene (BT) with H₂O₂as an oxidant under mild conditions. The removal of DBT, 4,6-DMDBT and BT could reach above 98% under the optimal conditions of n(S)/n(catalyst)/n(H₂O₂) = 220:1:880 at 60 °C for 2.5 h, 4.5 h and 5 h respectively, which improved to be a promising catalyst in the ODS process. The oxidative reactivity of the sulfur-containing compounds decreased according to DBT > 4,6-DMDBT > BT. We investigated the main factors affecting the process including temperature, the polymeric structures of catalysts, and O/S (H₂O₂/DBT) molar ratio in detail. Moreover, the catalyst can be reused 5 times with high recycling efficiency.

Full text of DOI:10.1016/j.ica.2016.02.065

Accepted Manuscript
Surfactant-Encapsulated High-nuclear Polyoxometalate Complexes for Cata-
lytic Oxidative Desulfurization of Model Oil
Tingting Wang, Ying Lu, Hongli Wu, Enbo Wang
PII:
S0020-1693(16)30092-5
http://dx.doi.org/10.1016/j.ica.2016.02.065
ICA 16935
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Inorganica Chimica Acta
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Please cite this article as: T. Wang, Y. Lu, H. Wu, E. Wang, Surfactant-Encapsulated High-nuclear Polyoxometalate
Complexes for Catalytic Oxidative Desulfurization of Model Oil, Inorganica Chimica Acta (2016), doi: http://
dx.doi.org/10.1016/j.ica.2016.02.065
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Surfactant-Encapsulated High-nuclear Polyoxometalate Complexes
for Catalytic Oxidative Desulfurization of Model Oil
Tingting Wang, Ying Lu,* Hongli Wu, Enbo Wang*
Key Laboratory of Polyoxometalate Science of Ministry of Education, Department of
Chemistry, Northeast Normal University, Renmin Street No. 5268, Changchun, Jilin
130024, PR China
* Corresponding author. Tel: +86-431-85098787, Fax: +86-431-85098787.
E-mail: luy968@nenu.edu.cn (Ying Lu), wangeb889@nenu.edu.cn (E. B. Wang)

Abstract
Two novel surfactant-encapsulated high-nuclear polyoxometalates catalysts
(DODA)20[(HPMo6O21)4(O2CCH2CO2)6]•27H2O and
(DODA)10[(HPMo6O21)2(C2O4)3]•11H2O have been prepared and characterized by TG,
1
FT-IR, H NMR and UV-vis. They were used for the oxidative desulfurization of
model oil containing sulfur compounds such as dibenzothiophene (DBT),
4,6-dimethyldibenzothiophene (4,6-DMDBT), benzothiophene (BT) with H2O2 as an
oxidant under mild conditions. The removal of DBT, 4,6-DMDBT and BT could
reach above 98% under the optimal conditions of n(S)/n(catalyst)/n(H2O2) = 220 : 1 :
880 at 60 ℃ for 2.5 h, 4.5 h and 5 h respectively, which improved to be a promising
catalyst in the ODS process. The oxidative reactivity of the sulfur-containing
compounds decreased according to DBT > 4,6-DMDBT > BT. We investigated the
main factors affecting the process including temperature, the polymeric structures of
catalysts, and O/S (H2O2/DBT) molar ratio in detail. Moreover, the catalyst can be
reused 5 times with high recycling efficiency.
Key words: surfactant-encapsulated; high-nuclear polyoxometalates; oxidative
desulfurization; model oil.

1. Introduction
Polyoxometalates (POMs), as one kind of important molecule-based nanomaterials
of the early transition metal oxides, have been applied in almost all fields, such as
catalysis, photoelectric functional materials, and medicinal chemistry [1-8]. The
studies of POMs as catalysts have attracted the most attention of POMs chemists, and
design and syntheses of high activity, high stability and recycled POMs catalysts are
the goals that researchers committed to achieve. We all know that most homogeneous
catalysts are usually efficient, but they are difficult to separate and reuse from the
solution. Nevertheless, heterogeneous catalysts can be recovered easily except they
show relative long reaction time. Therefore, people committed to make catalysts both
have good efficiency and easy recycling such as temperature-responsive catalyst,
self-separation catalyst and phase-transfer catalyst [9-12]. Normally, POMs exist in
solid and crystalline states, which limit their activity due to their poor solubility in
organic solvents. In this context, a lot of new organic-inorganic salts were synthesized
such as the surfactant-encapsulated POMs which usually consists of various
quaternary ammonium cations and POMs anions [13-14]. Various POMs have been
encapsulated by surfactants, for example, Keggin-, Dawson-, Anderson- and
Preyssler-type POMs, etc [15]. The surfactant cations and POMs anions connected via
electrostatic interaction [16-17]. Due to the encapsulation of surfactant, the resulting
hybrids no longer dissolve in water but can be soluble in chloroform, benzene and
other organic solvents increasing their processability and miscibility with organic
matrices. For this reason, the sufactant-encapsulated POMs catalysts usually exhibit

high activity because they were soluble in the organic solvents. Apart from this, the
sufactant-encapsulated POMs catalysts can be easily recovered by many methods, for
example, some of which were temperature-controlled, which can precipitate from the
reaction solution when the temperature decreased and be recovered by centrifugation
[18]; and extraction with a polar extractant is also a common approach to separating
and recovering these catalysts [19-20].
Conventional hydrodesulfurization (HDS) is the currently adopted method in
industry to remove the sulfur compounds in fuel [21], but it will cost much to remove
the refractory sulfur-containing compounds such as dibenzothiophene (DBT) and its
derivatives to become the ultra low sulfur diesel (ULSD) [22]. Oxidative
desulfurization (ODS) is regarded as a promising strategy to remove the refractory
aromatic thiophenes [23-24]. In recently years, POMs as catalysts for ODS processes
have been widely researched [25-28], especially the surfactant-encapsulated POMs
(SEPs) which not only exhibit high activity and selectivity but also can be easily
recovered. In recent years, many SEPs as catalysts were applied in ODS process. Li
and co-workers [29] have reported that SEP catalyst [(C18H37)2N(CH3)2]3[PW12O40]
can selectively oxidize the sulfur-containing molecules present in diesel using H2O2
as an oxidant under mild conditions, which exhibits high performance (96%
efficiency of H2O2, is easily recycled, and ~100% selectivity to sulfones). Wu [30-31]
et al have empolyed (DODA)3PW12 (DODA = dimethyldioctadecylammonium) as
catalyst for catalytic sulfoxidation reactions, and demonstrated that supramolecular
interactions plays a crucial role in promoting the activity of the catalyst. Beyond that,

the reported SEPs applied in the ODS process were formed by various POMs
including Keggin-type [PW12O40]3-, [PMo10V2O40]3- [31-32], Dawson-type
[P2W18O62]6- [33], Anderson-type [IMo6O24]5- [34], Weakly-type [EuW10O36]9- [29a]
and isopolyoxovanadate [V10O28]6- [35], et al. However, the studies on the SEPs
formed by highnuclear POMs and their application in the ODS process are rare.
Recently, Niu and his co-workers [36] have synthesized a series of highnuclear
−
complexes formed up by the polymerization of [HPMo6O21]2 units. Considering that
the polymeric structure of the highnuclear complexes may increase active sites and
catalytic efficiency, we synthesized SEP catalyst combing the highnuclear POMs
anions built by [HPMo6O21]2− units with surfactant cations (Fig. 1 and Fig. 2),
(DODA)20[(HPMo6O21)4(O2CCH2CO2)6]•27H2O(SEP-1)
and
(DODA)10[(HPMo6O21)2(C2O4)3]•13H2O (SEP-2). We investigated the oxidation
desulfurization of SEP-1 and SEP-2 in the model oil with the hydrogen peroxide as
oxidant under optimized reaction conditions and studies the influence of the different
polymeric structure on catalytic performance.
2. Experience
2.1. Materials and Methods
Commercially available 30 wt% H2O2, n-hexane, were purchased from Sinopharm
Chemical Reagent Co. Ltd. Dimethyl distearylammonium chloride (DODACl) was
commerical products from Aladdin Reagent Co. Ltd. (Shanghai, China) and used
without further purification. DBT, BT and 4,6-DMDBT were obtained by
Sigma-Aldrich.
(NH4)20[(HPMo6O21)4(O2CCH2CO2)6]•27H2O
(POM-1)
and

(NH4)8H2[(HPMo6O21)2(C2O4)3]•13H2O (POM-2) was prepared according to
literature procedure [36]. FT-IR spectra were recorded in the range of 400-4000 cm-1
1
on an Alpha Centaurt FT-IR Spectrophotometer with pressed KBr pellets. H NMR
spectrum (CDCl3) was recorded on an AV-400 spectrometer (Bruker Corporation,
Germany). UV-vis spectra were performed on an Agilent (8453) UV-vis diode-array
spectrometerusing quartz cells of 1 cm optical path. TGA ware recorded with the
powder sample on a Perkin-Elmer TGA instrument flowing N2 with a heating rate of
10 °C min-1. Elemental analyses (H, C, and N) were obtained with performed on a
Perkin-Elmer 2400 C, H, N elemental analyzer. Mo and P were determined by a
Leaman inductively coupled plasma (ICP) spectrometer. The products were analyzed
by GC-MS on a agilent 5975-6890N. The HPLC analysis were carried out using a
Shimadzu LC-15C instrument on a C18 column and detected by UV detector (254 nm)
at 30 °C through eluting with CH3CN/H2O (90 : 10) at a flow rate of 1 mL min-1.
2.2. Syntheses
2.2.1. Synthesis of SEP-1.
POM-1 (238 mg, 0.05 mmol) was dissolved in water (20 mL), and then DODACl
(587 mg, 1 mmol) in chloroform (30 mL) was slowly added dropwise to the resultant
solution with stirring. The initial molar ratio of POM-1 to DODACl was controlled at
1 : 20. After the solution was stirring for about 6 h at room temperature, the organic
phase was separated and evaporated the chloroform to dryness then the solid SEP-1
was obtained. The product was stored in a vacuum desiccator for the measurements.
The complex was characterized by FT-IR, TG, elemental analysis, 1H NMR

spectroscopy and UV-vis. IR (KBr, cm-1): υ = 3424 (w), 2930 (s), 2851 (s), 1585 (w),
1469 (m), 1347 (w), 1102 (w), 894 (s), 800 (w), 692 (s), 570 (w), 527 (w).
2.2.2. Synthesis of SEP-2.
The synthesis of SEP-2 followed the same procedure as for SEP-1, using the
POM-2 instead of the POM-1. The initial molar ratio of DODA·Cl to POM-2 was
kept at 10 : 1. IR (KBr, cm-1) for SEP-2: υ = 3463 (s), 2932 (s), 2847 (s) 1640 (s),
1462 (m), 1336 (m), 1069 (s), 1001(w), 886 (s), 780 (w), 675 (s), 568 (w), 532 (w).
2.3. Preparation of Model Oils.
Different model oils were prepared in the following processes. 1.466 g DBT was
dissolved in 500 mL n-hexane to obtain the model oil, the sulfur content of which was
500 µg mL-1. Other kinds of model oil were prepared by dissolving the corresponding
moles of 4,6-DMDBT and BT in n-hexane which the sulfur contents were both 500
µg mL-1.
2.4. Catalytic Oxidation of Dsulfurization in Model Oil
For a typical catalytic oxidation reaction, freshly prepared SEP-1 catalyst (6.0 mg,
0.365 µmol) was added to the model oil (5 mL) in the 10 mL round-bottom flask. The
reaction system was allowed to stabilize at 60 °C under continuous stirring,
meanwhile the catalyst was dissolved in the model oil. Then H2O2 (4 eq, 30 wt%) was
added dropwise when temperature stabilized. During the reaction, these oxygenated
DBTs were highly polarized and decreased the solubility in the model oil [37]. The
reaction progress was determined by TLC (n-hexane/ethyl acetate 2:1) at different
time intervals. When the reaction finished, the round-bottom flask was immersed in

an ice-water bath. Both DBT-sulfone and catalyst were precipitated as white solids
[38]. The upper clear solution was removed after separation by means of
centrifugation and analyzed by HPLC. The catalytic oxidation reactions of
4,6-DMDBT and BT were also performed using similar procedure. The catalytic
oxidation reaction of SEP-2 followed the same procedure as for SEP-1, using the
SEP-2 (5.6 mg, 0.730 µmol) instead of SEP-1 as the catalyst, the initial molar ratio of
SEP-1 to SEP-2 was kept at 1 : 2.
3. Result and discussion
3.1. Characterization of the Catalyst and Product
In the IR spectra of the solid-state SEP-1, SEP-2 (Fig. S1), bands at 2923 (vas
CH2), 2844 (vs CH2), and 1469 cm-1 (d CH2) (2932, 2847, 1462 cm-1 for SEP-2) are
assigned to CH2 antisymmetric and symmetric stretching modes of DODA alkyl
chains, and strong bands are observed at 1589, 1347, 894, 800, 699 cm-1 (1640, 1336,
886, 780, 675 cm-1 for SEP-2) for vibrations of POM-1. Some characteristic peaks at
such as 1589, and 1347 cm-1 (1640, 1336 cm-1 for SEP-2) become weaker and also
the position of these peaks moved a little, which confirms the success of the
1
encapsulation step. Comparing the H NMR spectra of DODACl and SEP-1, SEP-2
1
(Fig. S2), we find that the H signal of the -CH2- group shifts from 1.25 ppm to 1.35
1
ppm (1.25 ppm to 1.27 ppm for SEP-2) and the H signal of the -CH3 group shifts
from 0.89 to 0.98 ppm (0.89 ppm to 0.90 ppm for SEP-2). All these signals of the
complexes have moved to the higher field, which confirms the existence of
electrostatic interactions between the organic cations and POM-1. Similar absorption

bands are observed in the UV-vis spectra of POM-1 at 221 nm (209 nm for POM-2)
and SEP-1 at 251 nm (245 nm for SEP-2) (Fig. S3). The band at 221 nm of POM-1
(209 nm for POM-2) removes to 251 nm (245 nm for SEP-2), which demonstrates
that the interaction between DODA+ and polyoxometalate anions. All the test above
proved that the surfactant has replaced the counter cation of POM-1 and POM-2. The
TGA analysis suggests a mass loss of 3.1 % (2.6 % for SEP-2) in the range of
20-100 °C (Fig. S4) resulting from the loss of water molecules in SEP-1 and SEP-2.
The number of crystallized water molecules established by elemental analysis and TG
analysis is 27 for SEP-1 (11 for SEP-2). Anal. Calc. For SEP-1
(C778H1650O125N20P4Mo24): C, 58.7; H, 10.4; N, 1.76; P, 7.8; Mo, 14.5. Found: C, 57.7;
H, 11.0; N, 1.36; P, 7.0; Mo, 14.1. According to the elemental analysis, ICP, TG
analysis,
the
chemical
formula
of
SEP-1
was
determined
as
(DODA)20[(HPMo6O21)4(O2CCH2CO2)6]·27H2O. The chemical formula of SEP-2
was determined as (DODA)10[(HPMo6O21)2(C2O4)3]·11H2O. Anal. Calc. For SEP-2
(C386H824O65N10P2Mo12): C, 58.9; H, 10.5; N, 1.8; P, 0.8; Mo, 14.6. Found: C, 57.7; H,
11.0; N, 1.56; P, 0.4; Mo, 13.9.
When the reaction finished, the round-bottom flask was immersed in an ice-water
bath. Both product and catalyst were precipitated as white solids and were separated
from the solution by centrifugation. The product was extracted by CH3CN at room
temperature. Then the CH3CN solution was distilled at room temperature until a white
crystal solid was produced and characterized by GC-MS (shown in Fig. S5) and IR
(shown in Fig. S6). The appearance of characteristic frequencies at 1288 cm−1 (νas,

SO2) and 1161 cm−1 (νs, SO2) confirmed that sulfone was the only product, which was
in accordance with the results of the GC-MS, the GC-MS analysis of model oil in the
reaction process indicated that the DBT, 4,6-DMDBT and BT were oxidized to
DBTO2, 4,6-DMDBTO2 and BTO2.
3.2. Effect of H2O2/DBT on the Desulfurization of Model Oil
The effect of the amount of H2O2 on the oxidation desulfurization of model oil
system under various H2O2/sulfur (O/S) molar ratios at 60 °C catalyzed by SEP-1 was
shown in Table 1. 1 mol sulfide usually need 2 mol hydrogen peroxide when the
substrate all convert to sulfone in theory, but the actual experiment data show that the
removal of sulfide can only reach 86.2 %, because the oxidant decomposed in the
actual reaction inevitably. The removal of sulfide could reach 99.4% when the
equivalent of hydrogen peroxide is 4. We can see from the results of the experiments
that when the H2O2/DBT molar ratio was increased from 2 : 1 to 8 : 1, the removal of
DBT increased from 86.2% at O/S = 2 to 99.4% at O/S = 4 in 2.5 h, when increasing
the amount of oxidant slightly. Further increasing the O/S ratio to 6 and 8, the
removal of DBT didn’t change too much. So in view of the cost of the oxidant and the
productivity, O/S molar ratio at 4 was the appropriate condition. (Entry 3).
3.3. Effect of Temperature on the Desulfurization of Model Oil.
The effect of temperature on the desulfurization of DBT in the model oil catalyzed
by SEP-1 was investigated in Table 2 The removal of substrate increased
significantly with the reaction temperature changed from 45 °C to 60 °C. It can be
found that DBT was almost eliminated completely at 60 °C after 150 min. Moreover,

when the temperature dropped to 55, 50, or 45°C, the removal of DBT was not so
perfect as the 60 °C, which can only reach 92.2%, 82.3%, and 72.5% respectively. In
view of the desulfurization effect, 60 °C was better than the others and too high
temperature will contribute to the decomposition of H2O2, so the reaction temperature
of 60 °C was recommended.
3.4. Effect of Different Desulfurization System
DBT, 4,6-DMDBT, and BT were selected as sulfur compound representatives of
those refractory sulfur compounds in fuels. Removals of sulfide in different
desulfurization systems are shown in Table 3. 4,6-DMDBT and BT exhibited a much
lower reactivity than that of DBT. Remove all the DBT needs about 2.5 h, however
the other two sulfides 4,6-DMDBT and BT need 4.5 h, 5 h respectively. Without the
catalyst SEP-1, the removals of DBT, 4,6-DMDBT and BT were merely 5.1 %, 2.1 %,
and 1.4 % respectively. When SEP-1 was used as a catalyst, the removal of DBT,
4,6-DMDBT and BT increased remarkable, reaching 99.4 %, 98.8 %, 98.6 %
respectively indicating that the catalyst SEP-1 played a important role in catalytic
oxidation desulfurization.
Compared with DBT and 4,6-DMDBT, the electron density of BT (5.696) in the
sulfur atom is lowest, resulting to its lowest reactivity. The electron density
differences of DBT and 4,6-DMDBT (5.758, and 5.760 for DBT and 4,6-DMDBT
respectively) [39, 40] is so small that they can be ignored, the activity of 4,6-DMDBT
is lower than DBT because of its steric hindrance. From the experiment result we can
know that the oxidant reactivity of the sulfide occurs in the following order: BT <

4,6-DMDBT < DBT and the reaction rates of these sulfur-containing compounds are
sensitive to the electron density on sulfur atoms and the steric hindrance of the
substituted groups of sulfur-containing compounds [34b].
3.5. The Effect of the Polymeric Structure on the Desulfurization of Model Oil
In 2013, Niu [36] group reported two highnuclear POMs formed by the
polymerization of [HPMo6O21]2− units, (NH4)20[(HPMo6O21)4(O2CCH2CO2)6]·27H2O
(POM-1) and (NH4)8H2[(HPMo6O21)2(C2O4)3]·11H2O (POM-2). POM-1 possesses a
−
cage-type structure built by four [HPMo6O21]2 units joined together by six V-type
dicarboxylate ligands. While POM-2 exhibits a pillar-type structure constructed by
two [HPMo6O21]2− units connected through three oxalate linkers. In order to
investigate the influence of the different polymeric structure on catalytic performance,
we synthesized SEP catalysts SEP-1 and SEP-2 combing the POM-1 and POM-2
with surfactant cations respectively and compared their catalytic performance on the
oxidative desulfurization of DBT. As shown in Table 3 (Entry 5, 6), the catalyst
SEP-1 exhibited higher catalytic activity than the catalyst SEP-2. It can be ascribed to
the effect of the different polymeric structure, as we control the two catalysts with the
same amount {HPMo6} catalytic active units during the catalytic process.
3.6. The Recycle of the Catalyst
The recycling of the SEP-1 catalyst was investigated by choosing DBT as a
substrate in the ODS system. When the first run was over, the round-bottom flask was
immersed in an ice-water bath. Both DBT-sulfone and catalyst were precipitated as
white solids, then were separated from the solution by centrifugation. Sulfone was

extracted by CH3CN at room temperature leaving the catalyst for the next experiment.
The catalyst could be recycled 5 times without significant decrease in activity (Fig. 3),
with the data 99.4%, 98.6%, 97.9%, 96.0%, 95.1% respectively. The desulfurization
rate of the catalyst decreased from 99.4% to 95.1% after five recycles may be caused
by the slight loss of catalyst during the catalyst seperation process. The catalyst was
1
characterized by IR (Fig. S7) and H NMR (Fig. S8) after being recycled 5 times,
1
from the IR spectra and the H NMR we find that the catalyst didn’t change after the
oxidative desulfurization of the model oil.
3.7. Supposed mechanism of desulfurization system
Based on the experiments and literatures [41-42], the overall mechanism of
catalytic desulfurization can be supposed as follows. Scheme 1 presents a schematic
illustration of the oxidation of DBT to sulfone over the active species from the SEP-1.
When SEP-1 (abbreviated as Mo) reacting with excess H2O2, the catalyst with active
oxygen (abbreviated as Mo(O)) was generated. Then an oxygen transmitted from the
Mo(O) to the substrate, the transition state (DBTO) that a sulfide with an active
oxygen formed, at the same time the initial Mo regenerated for the next cycle. The
active peroxo species Mo(O) transmitted an oxygen atom to the transition state which
lead to the formation of corresponding sulfone (DBTO2) and the regeneration of the
Mo, Mo is available to restart the catalytic cycle.
4. Conclusion
In this study, two novel surfactant-encapsulated high-nuclear polyoxometalate
catalysts composed of the high-nuclear poly-{HPMo6} POMs have been synthesized

1
and characterized by TGA, FT-IR, H NMR and UV-vis. They were used as catalysts
for the oxidation of model oil with H2O2 as an oxidant under mild conditions. We
investigated the main factors affecting the process including the experiment
temperature, the polymeric structure of catalyst, and O/S (H2O2/DBT) molar ratio in
detail. The reaction activity decreased according to the following order: DBT >
4,6-DMDBT > BT. The catalytic activity has a relationship with the polymeric
structures, as the two catalysts exhibited different catalytic activities when controling
the two catalysts with the same amount {HPMo6} catalytic active units during the
process. Moreover, the oxidation system can recycle 5 times with high recycling
efficiency. Therefore, this process provides a green, low-cost, and effective strategy to
remove sulfur from diesel.
Supplementary materials
IR spectra, TG, 1H NMR, UV-vis, GC-MS, and additional figures are available.
Acknowledgements
This work was financially supported by the Science and Technology Development
Project Foundation of Jilin Province (No. 20130101006JC), and the Open Project
Program of the Key Laboratory of Polyoxometalate Science of Ministry of Education
(No. 130014555).
References
[1] J. T. Rhule, C. L. Hill, D. A. Judd, R. F. Schinazi, Chem. Rev. 98 (1998) 327.
[2] R. Neumann, M. Gara, J. Am. Chem. Soc. 116 (1994) 5509.

[3] D. Mansuy, J. F. Bartoli, P. Battioni, D. K. Lyon, R. C. Finke, J. Am. Chem. Soc.
113 (1991) 7222.
[4] J. Song, Z. Luo, D. K. Britt, H. Furukawa, O. M. Yaghi, K. I. Hardcastle, C. L.
Hill, J. Am. Chem. Soc. 133 (2011) 16839.
[5] R. Xing, A. P. Zheng, F.Wang, L.Wang, Y. P. Yu, A. H. Jiang, Food. Chem. 175
(2015) 292.
[6] E. Rafiee, S. Eavani, Journal of Molecular Catalysis A: Chemical 380 (2013) 18.
[7] C. Ritchie, A. Ferguson, H. Nojiri, H. N. Mirs, Y. F. Song, D. L. Long, E.
Burkholder, M. Murrie, P. Kögerler, E. K. Brechin, L. Cronin, Angew. Chem. Int.
Ed. 47 (2008) 5609.
[8] (a) X. X. Xu, X. Gao., T. T. Lu, X. X. Liu, X. L. Wang, J. Mater. Chem. A 3
(2015) 198; (b) X. L. Wang, J. Luan, H. Y. Lin, C. Xu, G. C. Liu, J. W. Zhang, A.
X. Tian, CrystEngComm 15 (2013) 9995; (c) Y. Y. Zhou, S. Yao, J. H. Yan, L.
Chen, T. T. Wang, C. J. Wang, Z. M. Zhang, Dalton Trans. 44 (2015) 20435.
[9] M. Wende, J. A. Gladysz, J. Am. Chem. Soc. 125 (2003) 5861.
[10] L. Plault, A. Hauseler, S. Nlate, D. Astruc, J. Ruiz, S. Gatard, R. Neumann,
Angew. Chem. Int. Ed. 43 (2004) 2924.
[11] Y. Leng, J. Wang, D. Zhu, X. Q. Ren, H. Q. Ge, L. Shen, Angew. Chem. Int. Ed.
48 (2009) 168.

[12] H. Hamamoto, Y. Suzuki, Y. M. A. Yamada, H. Tabata, H. Takahashi, S.
Ikegami, Angew. Chem. Int. Ed. 44 (2005) 4536.
[13] Y. Z. Wang, H. L. Li, W. Qi, Y. Yang, Y. Yan, B. Li, L. X. Wu, J. Mater. Chem.
22 (2012) 9181.
[14] B. F. Zhang, P. C. Yin, F. D. Haso, L. Hu, T. B Liu, J. Cluster Sci. 25 (2014)
695.
[15] (a) H. L. Li, H. Sun, W. Qi, M. Xu, L. X. Wu, Angew. Chem. Int. Ed. 46 (2007)
1300; (b) W. Li, W. F. Bu, H. L. Li, L. X. Wu, M. Li, Chem. Commun. 30 (2005)
3785; (c) Y. Yang, L. Yue, H. L. Li, E. Maher, Y. G. Li, Y. Z. Wang, L. X. Wu,
V. W. W. Yam, Small 8 (2012) 3105; (d) W. F. Bu, H. L. Li, H. Sun, S. Y. Yin, L.
X. Wu, J. Am. Chem. Soc. 127 (2005) 8016; (e) A. Nisar, Y. Lu, J. Zhuang, X.
Wang, Angew. Chem. Int. Ed. 50 (2011) 3187.
[16] P. C. Yin, J. Wang, Z. C. Xiao, P. F Wu, Y. G. Wei, T. B. Liu, Chem. Eur. J. 18
(2012) 9174.
[17] D. G. Kurth, P. Lehmann, D. Volkmer, H. Cölfen, M. J. Koop, A. Müller, A. D.
Chesne, Chem. Eur. J. 6 (2000) 385.
[18] H. Y. Lü, J. B. Gao, Z. X. Jiang, Y. X. Yang, B. Song, C. Li, Chem. Commun. 2
(2007) 150.

[19] C. Li, Z. X. Jiang, J. B. Gao, Y. X. Yang, S. J. Wang, F. P. Tian, F. X. Sun, X. P.
Sun, P. L. Ying, C. R. Han, Chem. Eur. J. 10 (2004) 2277.
[20] P. P. Zhao, M. J. Zhang, Y. J. Wu, J. Wang, Ind. Eng. Chem. Res. 51 (2012)
6641.
[21] R. Prins, Angew. Chem. Int. Ed. 40 (2001) 1551.
[22] Y. Shiraishi, K. Tachibana, T. Hirai, I. Komasawa, Ind. Eng. Chem. Res. 41
(2002) 4362.
[23] H. X. Zhang, J. J. Gao, H. Meng, Y. Z. Lu, C. X. Li, Ind. Eng. Chem. Res. 51
(2012) 4868.
[24] P. D. Filippis, M. Scarsell, Ind. Eng. Chem. Res. 47 (2008) 973.
[25] N. Mizuno, M. Misono, Chem. Rev. 98 (1998) 199.
[26] C. L. Hill, C. M. Prosser-McCartha, Coord. Chem. Rev. 143 (1995) 407.
[27] N. Mizuno, K. Yamaguchi, K. Kamata, Coord. Chem. Rev. 249 (2005) 1944.
[28] K. Sato, M. Hyodo, M. Aoki, X. Q. Zheng, R. Noyori, Tetrahedron 57 (2001)
2469.
[29] (a) J. Gao, Y. Zhang, G. Jia, Z. Jiang, S. Wang, H. Lu, B. Song, C. Li, Chem.
Commun. 3 (2008) 332; (b) H. Lü, J. Gao, Z. Jiang, F. Jing, Y. Yang, G. Wang, C.

Li, J. Cat. 239 (2006) 369; (c) C. Li, Z. Jiang, J. Gao, Y. Yang, S. Wang, F. Tian,
F. A. Sun, X. Sun, P. Ying, C. Han, Chem. Eur. J. 10 (2004) 2277.
[30] M. Xu, H. L. Li, L. Y. Zhang, Y. Z. Wang, Y. Yuan, J. M. Zhang, L. X. Wu,
Langmuir 28 (2012) 14624.
[31] W. Qi, Y. Z. Wang, W. Li, L. X. Wu, Chem. Eur. J. 16 (2010) 1068.
[32] C. Komintarachat, W. Trakarnpruk, Ind. Eng. Chem. Res. 45 (2006) 1853.
[33] Y. N. Zhang, L. Wang, Y. L. Zhang, Z. X. Jiang, C. Li, Chin. J. Catal. 32 (2011)
235.
[34] (a) H. Y. Lü, Y. Zhang, Z. X. Jiang, C. Li, Green Chem. 12 (2010) 1954; (b) H.
Lü, W. Z. Ren, H. Y. Wang, Y. Wang, W. Chen, Z. H. Suo, Applied Catalysis A:
General 453 (2013) 376.
[35] N. F. Tang, Y. N Zhang, F. Lin, H. Y. Lü, Z. X. Jiang, C. Li, Chem. Commun.
48 (2012) 11647.
[36] D. H. Yang, S. Z. Li, P. T. Ma, J. P. Wang, J. Y. Niu, Inorg. Chem. 52 (2013)
8987.
[37] W. S. Zhu, P. W. Wu, Y. H. Chao, H. M. Li, F. Zou, S. H Xun, F. X. Zhu, Z.
Zhao, Ind. Eng. Chem. Res. 52 (2013) 17399.
[38] C. Li, Z. X. Jiang, J. B. Gao, Y. X. Yang, S. J. Wang, F. P. Tian, F. X. Sun, X. P.
Sun, P. L. Ying, C. R. Han, Chem. Eur. J. 10 (2004) 2277.

[39] S. Otsuki, T. Nonaka, N. Takashima, W.H. Qian, A. Ishihara, T. Imai, T. Kabe,
Energy Fuels 14 (2000) 1232-1239.
[40] Y. Shiraishi, K. Tachibana, T. Hirai, I. Komasawa, Ind. Eng. Chem. Res. 41
(2002) 4362-4375.
[41] A. M. Al-Ajloun, T. M. Daiafla, M. El-Khateeb, Journal of Molecular Catalysis
A: Chemical 275 (2007) 139.
[42] Y. Ishii, K. Yamawaki, T. Yoshida, T. Ura, M. Ogawa, J. Org. Chem. 52 (1987)
1868.

Figure and Table Caption
Scheme 1 The mechanism of desulfurization process.
Table 1 Effect of H2O2/DBT on the desulfurization of model oil.
Table 2 Effect of temperature on the desulfurization of model oil.
Table 3 Effect of Different Desulfurization System.
Figure 1 Schematic view of the synthesis of SEP-1, (a) POM-1, (b) surfactant
DODA+, (c) SEP-1.
Figure 2 Schematic view of the synthesis of SEP-2, (a) POM-2, (b) surfactant
DODA+, (c) SEP-2..
Figure 3 The recycle times on the DBT removal with SEP-1 as catalyst.

Scheme 1

Figure 1

Figure 2

Figure 3

Table 1
Removal
[%]
Entry
H2O2[eq]
Substrate
Product
t [min]
150
86.2
92.3
99.4
99.6
99.6
1
2
150
150
150
150
2
3
4
5
3
4
6
8
Reaction conditions: V (model oil) = 5 mL, T = 60 °C, n(catalyst 1) / n(DBT) = 1 :
220.

Table 2
Product
t
Entry
温度[℃]
Substrate
Removal, [%]
72.5
[min]
1
2
3
4
45
50
55
60
150
150
150
150
82.3
92.2
99.4
Reaction conditions: V (model oil) = 5 mL, T = 60 °C, n(catalyst 1) / n(DBT) = 1 :
220.

Table 3
Removal,
[%]
Entry
Substrate
Product
Catalyst
t [h]
1
2
3
4
5
6
7
5
98.6
1.4
SEP-1
none
5
4.5
4.5
2.5
2.5
2.5
98.8
2.1
SEP-1
none
99.6
92.1
5.1
SEP-1
SEP-2
none
Reaction conditions: n(H2O2)/n(DBT) = 4, V (model oil) = 5 mL, n(catalyst)/n(DBT)
= 1 : 220, T = 60 ℃

Two new surfactant-encapsulated high-nuclear polyoxometalate
catalysts
composed
of
the
poly-{PMo6}
(SEP-1)
POMs,
and
(DODA)20[(HPMo6O21)4(O2CCH2CO2)6]·27H2O
(DODA)10[(HPMo6O21)2(C2O4)3]·13H2O (SEP-2), have been synthesized,
and used as catalysts for the oxidative desulfurization of model oil with
H2O2 as an oxidant. The removal of sulfide could reach above 98% under
the optimal conditions.
Surfactant-Encapsulated High-nuclear Polyoxometalate Complexes
for Catalytic Oxidative Desulfurization of Model Oil
Tingting Wang, Ying Lu,* Hongli Wu, Enbo Wang*
Key Laboratory of Polyoxometalate Science of Ministry of Education, Department of
Chemistry, Northeast Normal University, Renmin Street No. 5268, Changchun, Jilin
130024, PR China

Highlight
(1) The catalyst is a rare example of surfactant-encapsulated POMs formed by
high-nuclear poly-{HPMo6} POMs.
(2) The removal of sulfide could reach above 98% under the optimal conditions.
(3) The catalyst can be reused 5 times with high recycling efficiency.