Baeyer–Villiger Oxidation of Cyclohexanone by Hydrogen Peroxide with Fe3O4@GO as Catalyst Under Solvent Free Conditions

Article abstract of DOI:10.1007/s10562-019-02765-z

Abstract: An efficient magnetic nanocomposite catalyst (Fe₃O₄@GO) was synthesized and utilized as a sustainable and convenient catalyst for Baeyer–Villiger oxidation. The catalyst was characterized by XRD, FT-IR, TEM, SEM, XPS, Raman

Full text of DOI:10.1007/s10562-019-02765-z

Catalysis Letters
https://doi.org/10.1007/s10562-019-02765-z
Baeyer–Villiger Oxidation of Cyclohexanone by Hydrogen Peroxide
with Fe O @GO as Catalyst Under Solvent Free Conditions
3
4
1
1
1
1
1
Guansheng Xiao · Xi Gao · Weiting Yan · Tao Wu · Xinhua Peng
Received: 17 January 2019 / Accepted: 22 March 2019
©
Springer Science+Business Media, LLC, part of Springer Nature 2019
Abstract
An efcient magnetic nanocomposite catalyst (Fe O @GO) was synthesized and utilized as a sustainable and convenient
3
4
catalyst ꢀor Baeyer–Villiger oxidation. The catalyst was characterized by XRD, FT-IR, TEM, SEM, XPS, Raman and VSM.
Under solvent ꢀree conditions, hydrogen peroxide as green oxidant, Fe O @GO showed an efcient catalytic activity and
3
4
excellent selectivity ꢀor Baeyer–Villiger oxidation at room temperature. Conversion oꢀ 2-methyl cyclohexanone and selec-
tivity oꢀ ε-heptanlactone were 84% and 94%, respectively. The catalyst can be magnetically reused and recycled ꢀor several
runs without any signiꢁcant loss in efciency and selectivity.
Graphical Abstract
An efcient magnetic nanocomposite catalyst (Fe3O4@GO) was synthesized to show high catalytic activity and excellent
selectivity ꢀor the Baeyer–Villiger oxidation under solvent ꢀree conditions with hydrogen peroxide.
Keywords Baeyer–Villiger oxidation · Hydrogen peroxide · Fe O @GO · Solvent ꢀree · Room temperature
3
4
1
Introduction
Graphene oxide contains oxygen-containing chemical
groups, ꢀor example, carboxyl groups, hydroxyl groups and
epoxyl groups [1–5]. Graphene oxide has many advantages
oꢀ high electrical conductivity, exceptional mechanical, opti-
cal properties, good wettability and surꢀace activity which
plays a very important role in improving the comprehensive
properties oꢀ thermal, electrical and mechanical materials.
In addition, it shows a reasonable hydrophilic ability which
Electronic supplementary material The online version oꢀ this
article (https://doi.org/10.1007/s10562-019-02765-z) contains
supplementary material, which is available to authorized users.
*
Xinhua Peng
xhpeng@mail.njust.edu.cn
ꢀ
orm steady colloidal suspensions in water media so that it is
1
School oꢀ Chemical Engineering, Nanjing University
oꢀ Science and Technology, Nanjing 210094, China
going to be a new material in many reactions [6–9].
Vol.:(0
1
123456789)
3

G. Xiao et al.
The heterogeneous metal-catalysts provide considerable
advantages which are efcient to be reused. [10–13] Moreo-
ver, in recent years, the magnetic separation oꢀ catalysts has
attracted much attention more than ꢁltration or centriꢀuga-
tion because it avoids the loss oꢀ the catalyst. [14, 15] There-
(002)
ꢀ
ore, Fe O supported catalyst plays an important role in
3 4
(311)
organic reaction, such as Baeyer–Villiger oxidation.
As we all known, the products oꢀ Baeyer–Villiger oxida-
tion are lactones and esters which are important synthetic
intermediates in the agrochemical, chemical, pharmaceu-
tical industries [16–19]. Traditionally, the oxidants oꢀ the
reaction are perchloric peroxide benzoic acid, peroxy ben-
zoic acid and other peroxy acids producing a lot oꢀ waste
and by-products [20–22]. Thereꢀore, it is necessary to use
environment-ꢀriendly oxidation, ꢀor example, hydrogen per-
oxide provides a high content oꢀ active oxygen and water
is the only by-product. Recently, various substances with a
high surꢀace area like zeolites, montmorillonite clay miner-
als have been used ꢀor the stabilization oꢀ metal nanopar-
ticles, and diꢂerent types oꢀ homogeneous, heterogeneous
and enzyme catalysts were used in Baeyer–Villiger oxida-
tion [23–35]. Specially, Corma ꢀound that Sn–zeolite beta
showed an excellent activity and selectivity ꢀor Baeyer–Vil-
liger oxidation [36].
(
440)
(
511)
(
220)
(400)
b
a
(
111)
1
0
20
30
40
50
60
70
80
2
theta/degree
Fig. 1 Powder XRD pattern oꢀ GO (a) and Fe O @GO (b)
3
4
b
a
We report it that the synthesis oꢀ Fe O magnetic parti-
3
4
cles supported graphene oxide (Fe O @GO), the catalyst
3
4
shows good activity and selectivity oꢀ cyclic ketones in
Baeyer–Villiger oxidation. Fe O @GO is a green and ef-
3
4
cient heterogeneous catalyst ꢀor the oxidation under solvent
ꢀ
ree conditions. This catalytic system has many advantages
oꢀ room temperature, magnetic separation and solvent ꢀree.
Even the catalyst can be reused several times without sig-
niꢁcant loss in its catalytic activity.
4000
3500
3000
2500
2000
1500
1000
500
-1
Wavenumber(cm )
2
Experimental
Fig. 2 FT-IR spectrum oꢀ GO (a) and Fe O @GO (b)
3
4
2.1 Synthesis of GO
The modiꢁed Hummers method was used to prepare the gra-
phene oxide [37].The mixture oꢀ 5 g graphite powder, 2.5 g
potassium persulꢀate and 2.5 g phosphorus pentoxide were
added to 12 mL oꢀ concentrated sulꢀuric acid. Then they
were heated to 80 °C ꢀor 8 h. Aꢀter cooling to room tem-
perature, the mixture was ꢁltered and washed with deionized
water to neutral, the preoxidized graphite was dried at 50 °C
in an oven under vacuum. The preoxidized graphite (2 g),
with ice water bath, was added to 46 mL oꢀ concentrated sul-
oꢀ water and 4 mL hydrogen peroxide were added into it
with ꢁltering. Whereaꢀter, the crude material was cleaned
by 250 mL oꢀ hydrochloric acid solution (v/v 1:10) until no
sulꢀate ion was exited. At the end, the graphene oxide was
dried at 70 °C in a vacuum oven.
2.2 Synthesis of Fe3O4@GO
0.4 g oꢀ graphene oxide was added to 150 mL oꢀ deionized
water under ultrasonic dispersion ꢀor halꢀ an hour. Firstly,
0.950 g oꢀ FeCl3 6H2O and 0.410 g oꢀ FeCl2 4H2O were
added to 25 mL deionized water. The solution was added
slowly to the GO aqueous solution in a nitrogen ꢃow, then
the ammonia (30 wt%) was added to maintain pH at about
ꢀ
(
ꢀ
uric acid under 20 °C. Aꢀter that, potassium permanganate
6 g) was added slowly and the mixture was heated at 35 °C
or 2 h. Next, the 100 mL oꢀ deionized water was added
slowly and the temperature oꢀ reaction was 95 °C keeping
ꢀor 15 min. Aꢀter the reaction was completed, an amount
1
3

Baeyer–Villiger Oxidation of Cyclohexanone by Hydrogen Peroxide with Fe O @GO as Catalyst…
3
4
Fig. 3 TEM images oꢀ Fe O @
3
4
GO (a, b); SEM images oꢀ
Fe O @GO (c, d)
3
4
D
G
b
a
500
1000
1500
2000
2500
-1
Raman Shift (cm )
Fig. 5 Raman spectroscopy oꢀ GO (b) and Fe O @GO (a)
700
710
720
730
3
4
Binding Energy(eV)
1
0 and the reaction was heated at 80 °C ꢀor 1 h. Finally, the
Fig. 4 XPS oꢀ Fe O @GO and the results oꢀ deconvolution (black:
3
4
mixture was centriꢀuged to get solid which was washed by
ethanol ꢀor three times, and dried at 90 °C in oven under
vacuum.
experimental XPS spectrum; blue: background; red: best curve ꢁt;
purple: spectrum ꢀor FeO; green: spectrum ꢀor Fe O ; orange: 2P
1/2
2
3
spectrum ꢀor Fe O )
3
4
1
3

G. Xiao et al.
100
3
Results and Discussion
8
6
4
2
0
0
0
0
0
3
.1 Characterization of Fe O @GO
3 4
Graphene oxide exhibited an intense basal reꢃection at a
2θ value oꢀ 10.8°in PXRD analyses (Fig. 1a). Powder XRD
analysis oꢀ Fe O @GO showed six peaks at 2θ values oꢀ
3
4
2
0.41, 30.04, 35.48, 42.80, 57.08, 62.52 due to the (111),
-
-
-
-
20
40
60
80
(
220), (311), (400), (511) and (440) indices oꢀ a ꢀace cen-
tered cubic lattice oꢀ the Fe O which correspond to the
3
4
structure oꢀ pure stoichiometric Fe O (JCPDS Card No.
3
4
1
9-0629). All peaks were in the right peak positions which
indicated that Fe O consisted in the Fe O @GO (Fig. 1b).
3
4
3
4
-
100
FT-IR spectroscopy was used to conꢁrm the chemical
-10000
-5000
0
5000
10000
attachment oꢀ GO and Fe O @GO. GO exhibited various
3
4
Applied field(Oe)
prominent bands at 3408, 1713, 1600, 1391, 1229, and
−
1
1
093 cm which have been assigned to –OH and –C=O
Fig. 6 Magnetization hysteresis curve oꢀ Fe O @GO
3
4
oꢀ –COOH, aromatic –C=C–, carboxyl –C–O, epoxy –C–O
and alkoxy –C–O ꢀunctional groups, respectively (Fig. 2a).
In the IR spectrum oꢀ Fe O @GO, the new band appeared
3
4
−
1
2
.3 Catalytic Experiments
at 680 cm corresponding to Fe–O stretching vibration
(
Fig. 2b).
Ketone (2 mmol), H O (12 mmol, 30 wt%) and Fe O @GO
The morphological characterization oꢀ the obtained
2
2
3
4
(
0.02 g) were added in a ꢃask. The reaction was carried out
Fe O @GO nanocomposite was conducted by SEM
3 4
at room temperature ꢀor 5 h with stirring. The used catalyst
was separated simply by a magnet which was washed with
ethanol and dried in oven ꢀor the next run. The water in the
mixture was removed by using sodium sulphate. The con-
version and the selectivity oꢀ the reaction was determined
by GC.
(Fig. 3) and it shows that structures oꢀ GO are multilay-
ered, lamellar and partially ꢀolded. The TEM images oꢀ
Fe O @GO revealed that most oꢀ the Fe O nanoparticles
3
4
3
4
were dispersed on GO (Fig. 3).
The XPS spectra oꢀ Fe O @GO gave two peaks at
3
4
711.2 eV and 724.8 eV, which are characteristic oꢀ Fe
2
P
3/2
and Fe 2P respectively (Fig. 4). The peak at 711.2
1/2
consists oꢀ two peaks at 710.8 and 711.5 which are FeO
Table 1 Optimization oꢀ
the reaction conditions ꢀor
the oxidative synthesis oꢀ
Yield (%)b
Entry
Catalyst
Amount oꢀ
catalyst (g)
Solvent
Tempera-
ture (°C)
Time (h)
a
ε-heptanate by Fe O @GO
3
4
1
2
3
4
5
6
7
8
9
0
1
2
3
–
–
–
–
–
–
–
–
–
–
25
25
25
25
25
25
30
40
50
60
25
25
25
12
12
12
5
5
5
5
5
5
5
Trace
16
31
84
73
76
83
80
72
64
85
43
36
GO
Fe O
0.02
0.02
0.02
0.01
0.03
0.02
0.02
0.02
0.02
0.02
0.02
0.02
3
4
Fe O @GO
3
4
Fe O @GO
3
4
Fe O @GO
3
4
Fe O @GO
3
4
Fe O @GO
3
4
Fe O @GO
–
–
3
4
1
1
1
1
Fe O @GO
3
4
Fe O @GO
1,2-Dichloroethane
Acetonitrile
1,4-Dioxane
5
5
5
3
4
Fe O @GO
3
4
Fe O @GO
3
4
a
Reaction conditions: 2-methyl cyclohexanone (2 mmol), solvent (2 mL), H O (30 wt %) as oxidant
GC, yield oꢀ ε-heptanate
2
2
b
1
3

Baeyer–Villiger Oxidation of Cyclohexanone by Hydrogen Peroxide with Fe O @GO as Catalyst…
3
4
Table 2 Baeyer–Villiger oxidation oꢀ cyclic ketones using Fe O @
3
4
a
GO under solvent ꢀree conditions at room temperature
Entry Substrate
1
Product
Conversion
Yield (%)b
70
b
(
%)
78
2
3
90
52
89 (1st run)
84
84
83
8
8
9 (2nd run)
7 (3th run)
4
5
60
72
Scheme 1 A possible reaction pathway ꢀor Baeyer–Villiger oxidation
oꢀ ketones with H O as an oxidant
2
2
97 (1st run)
95
95
94
9
9
7 (2nd run)
6 (3th run)
3.2 Catalytic Activity
6
18
Trace
In order to achieve suitable reaction conditions ꢀor the oxi-
dative synthesis oꢀ ε-heptanate, 2-methyl cyclohexanone
(2 mmol), H O (12 mmol, 30 wt%) and Fe O @GO (0.02 g)
2 2 3 4
a
Reaction conditions: ketones (2 mmol), H O as oxidant(12 mmol,
2
2
were added in a ꢃask and the reaction was carried out ꢀor
h with stirring. The obtained result showed in Table 1 that
the ε-heptanate was not observed in the absence oꢀ catalyst
entry 1).When catalysts were GO and Fe O , the yield oꢀ
3
0 wt%), Fe O @GO (0.02 g), room temperature, 5 h, solvent ꢀree
3 4
5
b
GC, yield oꢀ product
(
3
4
and Fe O , respectively [38]. The mean relative peak area
2
3
2-methyl cyclohexanone was no more than 32%(entry 2, 3).
To our surprise, the highest yield oꢀ 84% was obtained aꢀter
5 h oꢀ stirring at room temperature (entry 4). However, the
amount oꢀ Fe O @GO increased to 0.03 g, and the yield oꢀ
oꢀ FeO and Fe O is 32.3% and 67.7%, which is consistent
2
3
with the theoretical ratio ꢀor Fe O .
3
4
Raman spectroscopy was used ꢀor investigating the elec-
3
4
tronic and phonon structure oꢀ the prepared GO and Fe O @
3
4
product decreased to 76%. With temperature oꢀ 30, 40, 50
and 60 °C (entry 7–10),the yield oꢀ product decreased ꢀrom
83 to 64%. Because higher temperature make hydrogen per-
oxide decompose quickly and the lactone was hydrolyzed
to organic acid. Using 1,2-dichloroethane as the solvent oꢀ
the reaction, the yield oꢀ product was obtained with excel-
lent yield oꢀ 85% (entry 11). On the other hand, the reaction
using acetonitrile and 1, 4-dioxane showed a lower yield
than solvent ꢀree because polar solvent diluted the concentra-
tion oꢀ hydrogen peroxide (entry 12, 13).
GO (Fig. 5). Two main peaks in the Raman spectrum oꢀ GO
2
were observable due to the ꢁrst order E mode ꢀrom sp
2
g
carbon domains (G band) and characteristic oꢀ a breathing
mode ꢀrom D band. The characteristic D and G bands oꢀ
−
1
GO are observed around 1349 and 1585 cm respectively.
Raman spectrum oꢀ Fe O @GO shows two prominent peaks
3
4
related to D band and G band.
The magnetization hysteresis curve oꢀ Fe O @GO
3
4
in Fig. 6 shows that the saturation magnetization up to
−
1
8
0.90 emu g and near zero remanence, the VSM indicates
The versatility and limitations oꢀ various substrates ꢀor
the Baeyer–Villiger oxidation oꢀ cyclic and chain ketones
were studied in Table 2. All the selected cyclic ketones
had a considerably good conversion. However, the yield oꢀ
cyclohexanone was 52% with a low selectivity (entry 2),
because the lactone was hydrolyzed to organic acid easily.
that the catalyst Fe O @GO has perꢀect paramagnetic nature
3
4
so that Fe O @GO can be separated by the magnet aꢀter the
3
4
reaction. The separated catalyst was used to next run with
same conditions in order to prove that the recovered Fe O @
3
4
GO has a wonderꢀul catalytic activity.
1
3

G. Xiao et al.
Table 3 Comparison oꢀ the Fe O @GO with some reported catalysts ꢀor Baeyer–Villiger oxidation oꢀ ketones
3
4
Entry
Catalyst
Oxidant
Solvent
Temp. (°C)
Time (h)
Yield (%)
1
2
3
4
Mg–Al mixed oxide [29]
Sn exchanged hydrotalcites [24]
Sn-supported on clay [39]
Fe O @GO
H O
1,4-Dioxane
Acetonitrile
1,2-Dichloroethane
Solvent ꢀree
70
70
12
4
2
89
58
93
84
2
2
2
2
2
H O
2
H O
Reꢃuxing temperature
Room temperature
2
H O
5
3
4
2
When the ortho-position was electron donating group, the
selectivity oꢀ product was higher than the one with electron-
withdrawing group (entry 1, 3, 4). Particularly, adamantane
ketone had a perꢀect conversion with an excellent yield
4 Conclusions
A novel catalyst oꢀ magnetic nanocomposite Fe O @GO
3
4
was prepared which showed high catalytic activity ꢀor
Baeyer–Villiger oxidation in hydrogen peroxide. Yield
oꢀ 2-methyl cyclohexanone being 84% with selectivity oꢀ
94% was obtained in a small-scale experiment (2 mmol oꢀ
2-methyl cyclohexanone). The optimum reaction condi-
tions were ꢀound to be as ꢀollows: molar ratio oꢀ hydrogen
peroxide and 2-methyl cyclohexanone was 6:1, dosage oꢀ
Fe O @GO was 0.02 g, room temperature, solvent ꢀree,
(
entry 5). On the contrary, the product oꢀ chain ketone was
obtained hardly (entry 6).
The recyclability oꢀ the catalyst was investigated in the
oxidation oꢀ cyclohexanone. The catalyst was separated ꢀrom
the reaction mixture simply because oꢀ its magnetic property,
and the recovered catalyst was washed with acetone, dried
in a desiccator and reused directly ꢀor another run without
3
4
ꢀ
urther puriꢁcation. The recyclability results clearly indicate
reaction time oꢀ 5 h. The catalyst was magnetically reused
and recycled ꢀor several runs with a little loss oꢀ efciency
and selectivity.
that the catalyst remained active without any signiꢁcant loss
in efciency (entry 3, 5). A ꢁltration test was carried out
in order to check whether any loss oꢀ nanoparticles Fe O
3
4
during the reaction. The reaction was allowed to run ꢀor 2 h,
then the catalyst was separated ꢀrom the reaction mixture,
then it was allowed to run without the catalyst ꢀor next 3 h.
It was ꢀound that the conversion aꢀter the ꢁrst 2 h, the con-
version oꢀ 2-methyl cyclohexanone is 63%. Until the end oꢀ
the reaction aꢀter separation oꢀ the catalyst, the conversion
remained unchanged. This conꢁrms that no leaching oꢀ any
active species oꢀ the catalyst in the reaction process.
Compliance with Ethical Standards
Conflict of interest There are no conꢃicts to declare.
References
1
2
3
.
.
.
Liu Y, Li Z, Shen W (2008) Recent Pat Chem Eng 1:1
Toebes ML, Prinsloo FF, Bitter JH (2003) J Catal 214:78
Kuila T, Mishra AK, Khanra P (2013) Nanoscale 5:52
A possible reaction pathway ꢀor Baeyer–Villiger oxi-
dation oꢀ ketones with H O as an oxidant is shown in
2
2
4. Gao W (2015) Springer International Publishing, pp 61–95
Scheme 1. In the presence oꢀ hydrogen peroxide, Fe(II)
perhaps gets oxidized to Fe(III) and Fe(III) is the possible
active site ꢀor the reaction. GO provides a huge surꢀace
area ꢀor the Fe O magnetic nanoparticles and the oxygen-
5. Marcano DC, Kosynkin DV, Berlin JM (2010) ACS Nano 4:4806
6
7
8
.
.
.
Dreyer DR, Park S, Bielawski CW (2009) Chem Soc Rev 39:228
Zhu Y, Murali S, Cai W (2010) Cheminꢀorm 22:3906
Chen D, Feng H, Li J (2012) Chem Rev 112:6027
3
4
9. Dikin DA, Stankovich S, Zimney EJ (2015) Nature 448:457
containing chemical groups make Baeyer–Villiger oxida-
tion occur easily. Hydrogen peroxide attacks at the more
electrophilic carbonyl carbon ꢀorming the Criegee inter-
mediate. Aꢀter rearrangement, a cyclic ester is obtained.
A comparison oꢀ diꢂerent reported catalysts with the
present work is shown in Table 3. It is clear that the pre-
sent catalyst shows a better catalytic activity under solvent
10. Dhakshinamoorthy A, Alvaro M, Garcia H (2012) Chem Commun
48:11275
11. Yang S, Zhang ZH, Chen Q (2017) Appl Organomet Chem e4132.
https://doi.org/10.1002/aoc.4132
12. Pescarmona PP, Jacobs PA (2008) Catal Today 137:52
13. Haag DR, Kung HH (2014) Top Catal 57:764
1
4. Wiltshire JG, Li LJ, Khlobystov AN (2005) Carbon 43:1151
5. Arash GC, Darvishnejad Z, Norouzi M (2015) Appl Organomet
Chem 29:170
1
ꢀ
ree conditions.
16. Krow GR (1993) Org React 43:251
1
1
1
2
2
2
7. Strukul G (2010) Cheminꢀorm 29:31
8. Ech JP, Carretero MA (2017) Chemcatchem 9:15
9. Fischer J, Holderich WF (1999) Appl Catal A 180:435
0. Schreiber SL, Liew WF (1983) Tetrahedron Lett 24:2363
1. Cesar JS, Jose RR (2011) Tetrahedron 2008:64
2. Benito A, Moustaꢀa FA, Miguel AS (1995) Tetrahedron Lett
36:3401
23. Corma A, Navarro MT, Renz M (2003) J Catal 219:242
1
3

Baeyer–Villiger Oxidation of Cyclohexanone by Hydrogen Peroxide with Fe O @GO as Catalyst…
3
4
2
2
2
2
2
2
4. Lei Z, Zhang Q, Wang R (2006) ChemInꢀorm 691:5767
5. Pillai UR, Sahle-Demessie E (2003) J Mol Catal A 191:93
6. Zhou XT, Ji HB, Yuan QL (2009) J Porphyr Phthalocyanines 12:94
7. Lei ZQ, Wei LL, Wang RR (2008) Catal Commun 9:15
8. Ma Y, Liang Z, Feng S (2015) Appl Organomet Chem 29:7
9. Olszówka JE, Karcz R, Napruszewska BD (2018) Catal Commun
35. Huo X, Liu J, Wang B, Zhang H, Yang Z, She X, Xi P (2013) J
Mater Chem A 1:651
36. Corma A, Renz M (2004) Chem Commun 35:550
37. Aunkor MTH, Mahbubul IM, Saidurb R, Metselaar HSC (2016)
RSC Adv 6:27807
38. Li P, Jiang EY, Bai HL (2011) J Phys D 44:7879
39. Hara T, Hatakeyama M, Kim A, Ichikuni N, Shimazu S (2012)
Green Chem 14:771
107:48–52
3
0. Guan FF, Ma TT, Yuan X (2018) Catal Lett 148:443
3
1. Modi CK, Solanki N, Vithalani R (2017) Appl Organomet Chem
32:e3910
Publisher’s Note Springer Nature remains neutral with regard to
3
3
3
2. Cuetos A, Rioz-Martínez A, Valenzuela ML (2012) J Mol Catal B
jurisdictional claims in published maps and institutional afliations.
74:178
3. Torres Pazmiño DE, Dudek HM, Fraaije MW (2010) Curr Opin
Chem Biol 14:138
4. Du GH, Liu ZL, Xia X, Chu Q, Zhang SM (2006) J Sol-Gel Sci
Technol 39:285
1
3