2
0
C. Yuan et al.
2
-
Table 2 The oxidation of different sulfides by the catalyst of WO
LDH@Fe
4
/
core could be readily utilized for the easy recovery and
recycling of the catalyst with no significant loss of catalytic
activity. Therefore, we expect this magnetic nanocompos-
ite catalyst to find applications in many other industrially
important catalytic processes such as catalytic oxidative
desulfurization of gasoline.
3 4
O
a
Entry
Sulfide
Yield/%
85
1
2
S
S
93
References
3
4
80
89
S
1
2
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Reaction conditions: 2 mmol substrate, 100 mg catalyst, 10 ml
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6
3
3
O
2 2
2 2
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8
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2
WO4 /LDH@Fe O exhibited good performance in
-
3
4
1
1
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recycling, with no remarkable loss of activity after five
times using (entry 3), indicating the slow deactivation of
the catalyst. ICP analysis of the filtrate after reaction
confirmed that tungstate contents were negligible. Also, it
should be noted that our catalyst provided a simple way for
the separation of the catalyst from the reaction mixture due
to the heterogeneous nature and magnetic properties of the
catalyst.
1
1
1
1
1
1
2
-
The WO4 /LDH@Fe O catalyst can be applied for
4
3
oxidation of a wide range of aryl and alkyl sulfides to
corresponding sulfoxides with 30 wt% H O as oxidant
19. Romanelli GP, Villabrille PI, C a´ ceres CV, V a´ zquez PG, Tundo P
2011) Catal Commun 12:726
(
2
2
2
0. Mori K, Kanai S, Hara T, Mizugaki T, Ebitani K, Jisukawa K,
Kaneda K (2007) Chem Mater 19:1249
1. Yuan C, Zhang Y, Chen J (2011) Chin J Catal 32:1166
(
Table 2). The catalyst seemed to be more active to the aryl
alkyl sulfides with bigger alkyl (entries 1 and 2). The for-
mation of sulfoxides from diaryl sulfide was relatively
difficult to achieve (entry 3), probably due to the sterically
hindrance. Compared to aryl alkyl sulfides, the catalyst was
more effective to dialkyl sulfide (entry 5).
2
22. Jia MK, Su GJ, Zheng MH, Zhang B, Shi SJ (2010) Sci China
Chem 53:1266
2
2
2
2
3. Shokouhimehr M, Piao Y, Kim J, Yang Y, Hyeon T (2007)
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Mou CY (2006) Chem Mater 18:5170
4
Conclusions
In this work, we have described a new magnetically
recyclable and efficient nanocomposite catalyst for the
oxidation of sulfides based on tungstate intercalated Mg–Al
27. Yuan C, Huang Z, Chen J (2011) Catal Lett 141:1484
2
8. Wu CL, Huan HE, Gao HJ, Liu G, Ma RJ, An YL, Shi LQ (2010)
Sci China Chem 53:514
2
9. Sels B, De Vos D, Buntinx M, Pierard F, Mesmaeker AK, Jacobs
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hydrotalcite-encapsulated Fe O nanocrystallites. This
3
4
catalyst exhibits several attractive features for practical
applications. Firstly, Fe O nanoparticles processed small
30. Choy JH, Oh JM, Park M, Sohn KM, Kim JW (2004) Adv Mater
6:1181
1. Darder M, Lopez-Blanco M, Aranda P, Leroux F, Ruizhitzky E
2005) Chem Mater 17:1969
2. Li L, Feng YJ, Li YS, Zhao WR, Shi JL (2009) Angew Chem Int
Ed 48:5888
1
3
4
3
3
particles size of 1–3 nm. Secondly, the magnetic core was
isolated and protected by hydrotalcite, making its use under
harsh reaction conditions possible. Thirdly, the magnetic
(
1
23