Selective dihydroxylation of methyl oleate to methyl-9,10-dihydroxystearate in the presence of a recyclable tungsten based catalyst and hydrogen peroxide

Article abstract of DOI:10.1039/d0nj02167a

The dihydroxylation of fatty methyl esters is of prime importance for the synthesis of surfactants and lubricants. The conversion of methyl oleate (MO) to 98percent yield of methyl-9,10-dihydroxystearate (MDHS) was performed in the presence of H2O2 and H3PW12O40 catalyst in the absence of a phase transfer agent. The study of the effect of hydrogen peroxide concentration revealed that significant catalytic activity was only achieved for an optimal amount of H2O2. A mechanism for this reaction was proposed where hydrogen peroxide reacts with H3PW12O40 to produce peroxo-phosphotungstate anions, which directly dihydroxylate MO. The recyclability of the catalyst was also studied. To this aim, a recyclable form of the heteropolyacid was synthesized using Cs cations (Cs2.3H0.7PW12O40). This catalyst was recycled up to three cycles without significant loss in catalytic performances. This journal is

Full text of DOI:10.1039/d0nj02167a

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March 2018
Pages 3963-4776
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Selective dihydroxylation of methyl oleate to methyl-9,10-
dihydroxysterate in the presence of a recyclable tungsten based
catalyst and hydrogen peroxide
Received 00th January 20xx,
Accepted 00th January 20xx
a
b
c
a
a
Nahla Araji, Gregory Chatel,* Audrey Moores,* François Jérôme and Karine De Oliveira Vigier*
DOI: 10.1039/x0xx00000x
The dihydroxylation of fatty methyl esters is of prime importance for the synthesis of surfactants and lubricants. The
conversion of methyl oleate (MO) to 98% yield of methyl-9,10-dihydroxysterate (MDHS) was performed in the presence of
H
2
O
2
and H
concentration revealed that significant catalytic activity was only achieved for an optimal amount of H
this reaction was proposed where hydrogen peroxide reacts with H 40 to produce peroxo-phosphotungstate anions,
which directly dihydroxylate MO. The recyclability of the catalyst was also studied. To this aim, a recyclable form of the
3
PW12
O
40 catalyst in absence of a phase transfer agent. The study of the effect of hydrogen peroxide
2 2
O . A mechanism for
3
PW12O
heteropolyacid was synthesized using Cs cations (Cs2.3
H
0.7PW12
O
40
) This catalyst was recycled up to three cycles without
.
significant loss in catalytic performances.
The first pathway (A) is the formation of diols via epoxidation of
the double bond and hydrolytic cleavage by water. In this
pathway, it is of importance to mention that this reaction
sequence was often used without detection or isolation of the
intermediately formed epoxides. Catalysts used for this reaction
Introduction
Fatty acid methyl esters (FAME) received a lot of attention as a
source of value-added chemicals owing to their low price and
the fact that they can be converted into several multi-
functionalized molecules through a relatively small number of
synthetic transformations. Thus, FAME is an important starting
material in a number of reported reactions, in particular, the
production of biodiesel through esterification reactions,1–8 and
the oxidative functionalization of FAMEs to produce epoxides or
acids used in a broad range of industrial applications such as
lubricants, plasticizers, hydraulic fluids, pharmaceuticals for skin
13-18
are essentially based on W or Mo.
One can mention that in
many studied reactions, diols are often observed as
intermediates in the full cleavage reaction, and are considered
as intermediates or by-products resulting from the epoxidation
of the double bond, but they are not the targeted products.11
The second pathway (B) is the direct dihydroxylation of the
double bond. The direct dihydroxylation reaction (pathway B)
of unsaturated fatty acids or esters was reported with Os or Ru
based catalysts and various co-oxidants to reoxidize the
reduced metal species, e.g. hydrogen peroxide, tert-butyl
hydroperoxide, N-methylmorpholin-N-oxide or potassium
7,9
diseases and cosmetic auxiliaries. Presently, many reactions
can be performed from C=C transformation of this class of
molecules, but the most investigated are epoxidation and C–C
1
0-12
cleavage reactions.
One interesting reaction is the
1
9
hexacyanoferrate (III). The direct dihydroxylation was also
performed using stoichiometric amount of permanganate. New
Os-containing catalysts were also investigated in the presence
dihydroxylation of FAME or fatty acids to produce the
corresponding diols which are used for the manufacture of
surfactants and lubricants. This reaction can be performed
through two mechanism pathways (Scheme 1).
2
0
of molecular oxygen leading to diols used for the manufacture
of surfactants. For example, 85% of methyl-9,10-
dihydroxysterate (MDHS) were obtained from methyl oleate
(MO) using a mixture of THF and water, with a THF/H O volume
ratio of 3:1 as solvent, in the presence of OsO and 4-
2
4
Pathway A
Pathway B
21
methylmorphine N-oxide. MDHS was used in that work as an
intermediate for the synthesis of lubricity improver which
contains at least one 1,2-dimethoxyester. All methods
mentioned above to produce diols present several drawbacks,
including the use of organic solvents without recovery, the
reliance on more than one step to produce the desired product
and sometimes the need for expensive and toxic oxidants.
H2O
Scheme 1. Reaction pathways for the dihydroxylation of methyl oleate
.
Among the usual oxidants used, H
attractive candidate since itis produced annually in 2.2×10 tons
worldwide, almost exclusively (> 95%) by means of the
2
O
2
is considered as an
a.IC2MP, UMR CNRS 7285-Université de Poitiers, France, ENSIP, B1, 1 rue Marcel
Doré, TSA 41105, 86073 Poitiers Cedex 9, France.
Univ. Savoie Mont Blanc, LCME, F-73000 Chambéry, France.
6
b.
c.
Centre for Green Chemistry and Catalysis, Department of Chemistry, McGill
University, 801 Sherbrooke St. West, Montreal, H3A0B8, Quebec, Canada.
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alkylanthraquinone autoxidation process, and only leads to Hydrogen peroxide (30 wt% aqueous H
Journal Name
2 2
O ) purchased from
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View Article Online
DOI: 10.1039/D0NJ02167A
water molecules as by-products when it is used in an oxidation Acros-Organics was used as primary oxidant. Methyl Oleate
2
2
reaction.
The
H
2
O
2
-mediated direct dihydroxylation of (MO), from Alfa Aesar, was purchased with a purity of 96% and
40, from Sigma-Aldrich, was used
unsaturated fatty acids or esters was studied in the presence of phosphotungstic acid H
3
PW12O
a Fe-tetra amido macrocylic complex23 or a resin-supported as an acid catalyst. 9,10-Epoxy methyl stearate (epoxide) was
sulfonic acid under metal-free conditions without any organic purchased with 99% purity from Santa Cruz factory from
2
4
solvent. In this study, they used Nafion SAC-13 at 90°C in the Toronto and was used as a calibration standard to quantify the
presence of 30% of H O at 70°C for 20h affording 80% yield of yield of the produced epoxide. In order to quantify MDHS
0
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2
the diols from oleic acid. Piazza et al. showed that alumina- (methyl-9,10-dihydroxystearate) was synthesized with a a 80%
catalyzed hydrolysis of fatty epoxides is an efficient way to purity from the oxidation of methyl oleate for quantification
25
synthesize polyhydroxy materials. Cecchini et al. reported the purposes. The purity of MDHS was verified by NMR and LCMS
oxidation of FAMEs (methyl oleate, methyl linoleate and methyl analysis and the MDHS was then used as a calibration standard.
linolenate) using oxovanadium complexes in the presence of The carbon mass balance was checked by H NMR and masss
1
CHCl
with 13% of epoxide after 6 h reaction at 50 °C.26
used as oxidant in biomass conversion to chemicals and some Catalytic tests
examples reported the combination of H and tungstic acid
for fatty acids conversion to dicaboxylic acids, azelaic acid, etc.
3
as solvent, where the best yield in MDHS was 87% along spectrometry analysis.
2 2
H O
is widely
2 2
O
All catalytic experiments were carried out in a 50 mL glass flask
fitted with reflux, starting from 5 mmol of the substrate (methyl
oleate) in the presence of 5 wt% of catalyst and the desired
2
7
For example, a high conversion of 90% and 80% selectivity in
desired diol during dihydroxylation reaction was observed in
the presence of this system. One can mention that a
amount of aqueous H
2 2
O (30%) (from 1.1 eq. (0.63g) to 1.5 eq.
(0.86g)). The reaction mixture was stirred (1400 rpm) at the
concentrated solution of H
added continuously to convert fatty acids.
excess of H is problematic on large scales due to safety
considerations. In the case of low concentrated solution of
, the sheer volume of the aqueous reagents required can
2 2
O (> 60%) is required and should be
defined temperature (from 50 to 80°C). At the end of the
reaction, the reaction media was cooled down rapidly and the
organic phase was extracted using ethyl acetate (40 mL) and
dried over anhydrous Na SO . After evaporation of the solvent,
2 4
the sample was diluted using 1 mL of pyridine and silylated by
adding hexamethyldisilazane (1 mL) and chlorotrimethylsylane
2
8,29
The use of an
2 2
O
30
2 2
H O
be detrimental to the reaction and phase transfer agent are
required.
The synthesis of diols from FAME require the control the
(1 mL). Sorbitol (2 mg), used as external standard, was added to
the sample before analysis by GC-FID. Each result corresponds
to one experiment, and no sample was taken.
selectivity and a concentrated solution of H
2 2
O . In order to use
a low concentrated solution of H , mass transfer agent are
2 2
O
often used in order to reach a yield to diols over 70%. The
catalysts used for this reaction are often homogeneous ones
and not recyclable. Herein, we wish to demonstrate that
methyl-9,10-dihydroxystearate (MDHS) can be produced from
methyl oleate (MO) using a one step process without the
addition of an organic solvent or a mass transfer agent in the
GC-FID analyses
Gas chromatography analyses (GC-FID) were performed using
an Agilent Technologies 456 series instrument equipped with a
flame ionization detector, using a column of 30 m×0.25mm×0.5
µm film thickness composed with phenyl (5%) dimethyl siloxane
(95%).
2 2
presence of an aqueous solution of H O (30%). Peroxo-
The conversion values of methyl oleate was calculated as shown
below:
phosphotungstate (POW) based catalyst can be used to perform
epoxidation reaction in a biphasic media containing an organic
solvent as demonstrated by the work of Venturello and
퐴ꢀ /퐴푠표푟푏ꢀ푡표푙 − 퐴푡 /퐴푠표푟푏ꢀ푡표푙
푀푂
푀푂
퐶표푛푣푒푟푠ꢀ표푛 ꢁ%ꢂ =
× 100
ꢀ
퐴 /퐴푠표푟푏ꢀ푡표푙
푀푂
31,32
D’Aloisio.
Previously, we have shown that an amphiphilic
dipyridinium peroxo-phoshotungstate ion pair was selective
and recyclable catalyst for the triphasic epoxidation of fatty
acids and esters with hydrogen peroxide.33 Based on these
results and on the state of the art, tungsten based catalyst
3
(H PW12O40) were chosen to synthesize MDHS. This catalysts
풊
푴푶
풕
푴푶
Where
푨
and
푨
represent the values of the area of methyl
oleate chromatographic peaks respectively at the initial time
time zero) and time of control. 푨풔풐풓풃풊풕풐풍 is the area of the
external standard.
The yields of products (MDHS and epoxide) at time of control t
were calculated as shown below:
(
was studied without the use of a phase transfer agent or organic
solvent. We also developed a recyclable version of this catalyst
2+
(
and Cs2.3
H
0,7PW12
O
40) relying on a cation exchange with Cs .
푚표푙 표푓 푝푟표푑푢푐푡 푓표푟푚푒푑
푌ꢀ푒푙푑 ꢁ%ꢂ = ꢀ
× 100
푛ꢀ푡ꢀ푎푙 푚표푙 표푓 푚푒푡ℎ푦푙 표푙푒푡푎푡푒
풊
풑
풕
풑
Where
푨
and
푨
represent the values of the area of the
product (MDHS or epoxide) chromatographic peaks
respectively at the initial time (time zero) and time of control.
The margin error for yields and conversions is around 3% for all
the results.
Experimental
Materials and methods
2
| J. Name., 2012, 00, 1-3
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The decrease in catalyst amount from 10 wt% to 5 wt% led to a
Results and discussion
View Article Online
DOI: 10.1039/D0NJ02167A
slight change at the beginning of the reaction (up to 30 min) and
after 30 min of reaction, similar trend was observed and both
In a first set of experiments, 5 wt% of phosphotungstic acid
catalyst loadings enabled 85% conversions after 2 h of reaction
(H PW12
3
O40) was added to 5 mmol of methyl oleate (MO) in the
-
(
Figure 2). The initial rate of the reaction increased from 165 h
presence of 1.1 eq. of H at 80 °C (Figure 1). After 2 min of
2 2
O
1
-1
to 842 h from 10 to 5 wt% loadings. A further decrease of the
amount of H 40 from 5 wt% to 2 wt%, led to a smaller
reaction, 15% of MO was converted and MDHS was produced
with 14% yield. Upon prolonged reaction time, conversion of
MO reached a maximum of 85% after 2 h of reaction with yields
of 84% and 1% in MDHS and epoxide, respectively. Interestingly,
H PW12O40 in the presence of H O featured an impressive
3 2 2
selectivity to MDHS of over 99% throughout the reaction
duration.
3
PW12O
-
1
-1
initial reaction rate from 842 h to 672 h but a complete
conversion of MO was observed after 2 h of reaction with a
catalyst amount of 2wt%. For 1 wt% of catalyst loading, the
reaction slowed significantly, with conversions systematically
lower at all-time points than all of the 3 other studied loadings
for a reaction time lower than 100 min. Above 100 h the MO
conversion is 90% against 85% for 5 wt% and 10 wt%. The initial
rate of the reaction was thus very low (95 h ) in the presence
of 1 wt% of catalyst and the conversion reached 90% after 2 h
of reaction. These results suggest that an optimal loading was
obtained at 2wt%, which can be rationalized by the fact that an
excess of catalyst may lead an excessively fast decomposition of
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0
-1
2 2
H O , while too low loadings fail to sustain the reaction as it is
reported in the literature. At this loading, we observed the
highest MO conversion (100%) as well as the highest yield in
3
4
MDHS (99%), at 80 °C using 1.1 eq. of H
necessary to control the ratio catalyst/H
MDHS yields from MO. In order to confirm this observation, the
effect of H content on the conversion of MO was then
studied (Figure 3). Variations in the amounts of H had drastic
2
O
2
2
. It seems that it is
O to obtain good
2
2 2
O
2 2
O
Figure 1. Oxidation of methyl oleate (5 mmol) to MDHS and epoxide in the presence of
5 wt% of H PW12O40 and 1.1 eq. of H O at 80 °C.
3 2 2
effects on the conversion. When decreased from 1.1 eq. to 0.5
eq. (molar), the conversion of MO decreased from 98% to 45%,
Reaction conditions were then explored with the aim to while the selectivity in MDHS remained high at 99% after 90 min
decrease the amount of both catalyst and H
used in the of reaction. Increasing oxidant content to 1.5 eq. led surprisingly
oxidation of MO. In all experiments described hereafter, the to only 1% conversion of MO. The H quantity was varied by
selectivity to MDHS remained higher than 98%, and thus, for altering the volume of its 30 wt% aqueous solution, thus
simplicity, results were solely expressed in terms of MO increased H content resulted in larger volumes of the
conversions.
aqueous phase. The existence of an optimum H content at
First, the acid catalyst loading was studied at 80 °C in the 1.1 eq. may be explained by the fact that at lower amounts, the
2 2
O
2 2
O
2 2
O
2 2
O
presence of 1.1 eq. of H
2
O
2
(Figure 2).
conversion is limited by the actual quantity of reagents
available.
Figure 2. Effect of catalyst amount on the conversion of methyl oleate using 1.1 eq. of
, 5 mmol of MO at 80 °C (the yield in epoxide in all these experiments was less than
2 2
H O
2%).
Figure 3. Effect of the hydrogen peroxide content on the conversion of methyl oleate
using 5 mmol of MO and 2 wt% of H
experiments was less than 2%).
3
PW12
O
40 at 80 °C (the yield of epoxide in all these
This journal is © The Royal Society of Chemistry 20xx
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If H
2
O
2
was added dropwise (1.1 eq.) with a flow of 0.05 mL.min- identified products with only 20% yield of MDHS foVriemw eArdtic.leTOhnelisnee
1
and that the reaction took place for 1h after the addition of poor yields clearly established that the DepOoI:x1i0d.1e03c9a/nD0nNoJt02b1e67Aa
2 2
H O , 78% of MO was converted to 77% of MDHS. If the addition significant intermediate in the dihydroxylation of OM studied
-
1
-
flow of H
2
O
2
was increased from 0.05 mL.min to 0.07 mL.min herein. In the presence of H
3
PW12
O
40, the hydrolytic cleavage of
1
and the reaction was pursued for 1 h the conversion of MO epoxide was not the main route, and the mechanism of the
reached 96% and 95% of MDHS was produced. These results reaction goes through a direct dihydroxylation of MO as
showed that in this case by playing on the addition rate of H
similar results are obtained than when H is added at the The effect of the reaction temperature was then studied (Figure
beginning of the reaction. At higher content (1.5 eq. of H ), 4). When it was decreased from 80 °C to 60 °C, it logically took
the reaction may be drastically affected by the presence of a a longer time, namely 4 h instead of 2h, to reach a similar
large aqueous phase when H was added in one time. To conversion of MO (98% vs. 95%). A further decrease in the
confirm this hypothesis, H (1.5 eq.) was added dropwise and temperature to 40 °C afforded poor MO conversions, the
we were pleased to see that with a flow rate of 0.07 mL.min , maximum observed being 20% (98% selectivity to MDHS) after
5% of MO was converted to 94% of MDHS, after 1 h of reaction 4 h of reaction.
after the addition of H ) showing that if the amount of H
is controlled, excellent yield of MDHS can be achieved.
2
O
2
described in the literature in the presence of tungstic acid.37
2 2
O
0
1
2
3
4
5
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8
9
0
1
2
3
4
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0
1
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0
1
2
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9
0
1
2
3
4
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8
9
0
2 2
O
2 2
O
2 2
O
-1
9
(
2
O
2
2 2
O
Based on these results, we determine that an optimal molar
ratio between hydrogen peroxide and the catalyst is required
(
around 550) to carry out this reaction in good yield with the
addition of H in one time. It is known that Keggin-type
can be transformed to peroxo-active species,
2 2
O
3
-
[
40
PW12O ]
3
-
4 2 2 4
{PO [W(O)(O ) ] } by an excess of hydrogen peroxide. It is a
reversible redox reaction where phosphotungstic acid is
generated after the oxidation of the desired substrate by
peroxo-phosphotungstate anions (active form). Based on the
literature a proposed catalytic mechanism for this reaction is
shown in Scheme 2.
Figure 4. Effect of the temperature on the conversion of methyl oleate using 1.1 eq. of
, 5 mmol of MO and 2 wt% of H 40 (the yield of epoxide in all these
experiments was less than 2%).
Active form
H O
2
3
PW12O
2
Inactive form
reduction
Interestingly, the increase of the reaction temperature to 100
°C led to a decrease in the conversion of MO from 98% to 80%
after 2 h of reaction. In fact, hydrogen peroxide is known to not
be stable at this temperature and may be degraded, which may
explain the decrease in MO conversion, by limiting the
formation of the active species. It can be pointed out that at
80 °C, a MO conversion higher than 95% was achieved after the
shortest of the explored reaction times (1 h) with 99%
selectivity of MDHS.
*
34
*
2 2 2
½ O was released and can be used to reoxidized the catalyst in addition of H O .
Scheme 2. Proposed mechanism of the oxidative reaction of methyl oleate in the
With the optimized reaction conditions at 1.1 eq. of H
of H 40 and 80 °C, we wanted to explore catalyst
recyclability. Unfortunately, phosphotungstic acid H PW12O40 is
2 2
O , 2 wt%
presence phosphotungstic acid and hydrogen peroxide based on the literature.
3
PW12O
According to the work of Noyori et al. and Strassner hydrogen
peroxide is used to produce the peroxo-phosphotungstate
anions that will react with MO in order to form a compound
with tungsten that will lead to the formation of MDHS and the
release of [PO
phosphotungstate anions.
epoxide was not an intermediate in this reaction,
complementary experiment was performed starting from
epoxide instead of MO using 2.5 mmol of epoxide
corresponding to a 55% conversion of MO after 30 min of
3
a strong acid soluble under aqueous conditions, which leads to
low pH around 1 under our conditions. After the reaction, it was
thus impossible to simply recover an active form of the catalyst
from the reaction medium. We thus explored the modification
of this catalyst in order to obtain a heterogeneous catalyst. In
the literature, Gharib et al. worked on the recycling of
phosphotungstic acid by the substitution of hydrogen atoms by
3-
4 3
(WO )12] that can be converted again to peroxo-
35,36
In order to prove that the
a
cesium (Cs2.5
Inspired by this study, we synthesized Cs2.3
structure was confirmed by ICP analysis. The recycling of
40 was then performed using the optimal
conditions previously described (1.1 eq. of H at 80 °C).
H
0.5PW12
O40),
using ultrasonic irradiation.38
40, which
H
0,7PW12O
reaction keeping similar amount of H
conversion of MO (0.66 g of H and 0.075 g of catalyst). After
0 min, 60% of the epoxide was converted to various non
2 2
O and catalyst used in the
Cs2.3H0.7PW12O
2 2
O
2 2
O
3
4
| J. Name., 2012, 00, 1-3
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However, in the presence of 2 wt% of Cs2.3
only 40% of MO was converted with 39% of MDHS after 2 h of catalyst and the results were compared tDoOtI:h1e0.1r0e3s9u/lDt0oNbJt0a2i1n6e7dA
H0.7PW12O
40 catalyst, XPS analysis were also conducted to analyze the sVuierwfaAcrteicloe fOntlhinee
reaction. In order to improve the reaction rate in order to be from the characterizations of commercial H
competitive with the homogeneous form, the catalyst amount (Figure 6) and after reaction (Figure 7).
was optimized to achieve a high yield of MDHS after 2h of
reaction. An increase of the catalyst loading from 2 to 6 wt% led
to an increase of the MDHS yield from 39 to 79% (MO
conversion of 80%) after 2 h of reaction. The catalyst recycling
was then studied using these reaction conditions. To this aim,
after each cycle, the reaction media was centrifuged, and the
recovered catalyst was then washed several time with ethyl
acetate and water, dried at 60 °C during 6 h and reused for the
next cycle.
3
PW12O40 before
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
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7
8
9
0
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0
1
2
3
4
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8
9
0
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2
3
4
5
6
7
8
9
0
Figure 6. XPS spectrum of W4f of commercial catalyst (left) and Cs2.3H0.7PW12O40 before
recycling (right).
XPS spectra of W4f of H
recycling (Figure 6) showed 2 peaks at 36.4 eV and 38.5 eV
corresponding to tungsten oxide WO species of the
40 recovered after the first and the
cycle, contained two forms of tungsten oxide: WO and WO
3
PW12O40 and Cs2.3H0.7PW12O40 before
3
PO
4
4
(WO
3
)
123-. Cs2.3
H
0.7PW12
O
th
3
2
(
at 35.1 eV) meaning that the catalyst was modified after
reaction. The presence of WO may have an impact on the
recyclability process of the heterogeneous catalyst limiting the
number of active species on the catalyst. However, the catalyst
can be recyclable up to three cycles without using organic
solvent or phase transfer agent.
2
Figure 5. Recyclability of Cs2.3H0.7PW12O40 using 5 mmol of MO, 1.1 eq. of
hydrogen peroxide and 6 wt% of catalyst at 80 °C for 2 h.
The catalyst was recyclable up to 3 cycles without significant
loss in MO conversion (76-80%) and yield (75-79%) in MDHS
(Figure 5). After the third cycle, the conversion of MO and the
Name
W 4f WO3 36.3918 1.0023 GL(30) 51663.16 52.5
W 4f WO3 38.5317 1.0086 GL(30) 39147.97 39.7
W 4f W5+ 35.1042 0.9892 GL(30) 4516.37 4.6
W 4f W5+ 37.2442 0.9892 GL(30) 3025.97 3.0
Pos.
FWHM L.Sh.
Area
%Ar
yield of MDHS decreased.
In order to understand this loss of activity, Cs2.3
characterized before reaction and after the first and 4 cycle.
Elemental analysis of W and P was then performed on the
Cs2.3H0.7PW12O40 catalyst before and after recycling (Table 1).
Elemental analysis showed no significant difference in
phosphorus content before and after reaction while a clear
difference was observed with tungsten measurements. Before
50
40
30
20
10
H
0.7PW12
O40 was
th
recycling, Cs2.3
fourth cycle, the weight percentage of W decreased from 63 to
6%. Thus activity loss was assigned to W leaching, which
H0.7PW12O40 contained 63 wt% of W and after the
5
4
4
40
36
32
Binding Energy (eV)
28
became too significant past the fourth cycle.
Figure 7. XPS spectrum of W4f of Cs2.3H0.7PW12O
40 after the first cycle (left) and the 4th
Table 1. Weight percentage of W and P measured by ICP in Cs2.3H0.7PW12O40 before
and after recycling.
cycle (right).
Catalyst
W (wt%)
P (wt%)
Conclusions
Fresh Cs2.3
H0.7PW12
O
40
63
63
0.9
0.9
3
Herein, we have demonstrated that H PW12O40 can be used to
selectively convert methyl oleate into methyl-9,10-
dihydroxystearate (MDHS) with 99% yield. The yield to MDHS is
higher than what was reported in the literature up to now
87%). The mechanism involved in this reaction was the direct
dihydroxylation of MO. The active species were peroxo-
Cs2.3
Cs2.3
H
H
0.7PW12
O
O
40 after the 1st run
40 after the 4th run
0.7PW12
56
0.8
(
This journal is © The Royal Society of Chemistry 20xx
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6 K. Tsubone, Japanese Patent 2005272429, 2005V. iew Article Online
phosphotungstate anions formed in the presence of a certain
amount of H O that can be converted to phosphotungstate
2 2
anions after the dihydroxylation of MO. It was shown that no
organic solvent, no phase transfer agent was required during
7 K. Tsubone, Japanese Patent 2005263765, 2005.
DOI: 10.1039/D0NJ02167A
8 K. Weissermel, H.-J. Arpe, Industrielle Organische Chemie.
Wiley-VCH,Weinheim (Germany), 1998.
19 B. Cornils, W. A. Herrmann, R. Schlögl, C.-H. Wong, C.-H.
(Eds.): Catalysis from A to Z – A Concise Encyclopedia. Wiley-
VCH, Weinheim (Germany), 2000.
0 K. Yonehara, Y. Sumita, Japanese Patent 2005336064, 2005.
1 Y.-K. Lim, M. J. Lee, C.-S.Jung, J.-R. Kim, E. S.Yim, US Patent
US20130053590, 2013.
this reaction, but an appropriate molar H
around 550 in the optimized conditions) is needed to reach the
highest yield to MDHS from MO. Hence, H concentration was
0%, and under this concentration phase transfer agent are
often required. In the absence of phase transfer agent, high
concentration of H are used which can lead to safety issue
this study, by controlling the molar H /catalyst ratio, diols
from MO were obtained with low concentrated solution of H
and no additional organic solvent. Moreover, a recyclable form
was synthesized (Cs2.3 40) and was successfully
2 2
O /catalyst ratio
(
2
2
2 2
O
3
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
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7
8
9
0
1
2
3
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9
0
1
2
3
4
5
6
7
8
9
0
22 R. Hage, A. Lienke, Angew. Chem. Int. Ed., 2005, 45, 206.
In 23 E. J. Geiger, N. M. Becker, L. A. Armbruster, WO Patent
2
O
2
.
2
006094227, 2006.
2 2
O
2
2
4 Y. Usui, K. Sato, M. Tanaka, Angew. Chem. Int. Ed., 2003, 42,
623.
5 G. J. Piazza, A. Nunez, T. A. Foglia, J. Am. Oil Chem. Soc., 2003,
80, 901.
2 2
O
5
H0.7PW12O
recycled up to three cycles without significant loss in the 26 M. M. Cecchini, F. De Angelis, C. Iacobucci, S. Reale, M.
catalytic performances.
Crucianelli, Appl. Catal. A: Gen., 2016, 517, 120.
2
7 S. P. Teong, X. Li, Y. Zhang, Green Chemistry, 2019, 21, 5753;
M. Melchiorre, V. Benessere, M. E. Cucciolito, C. Melchiorre ,
F. Ruffo , R. Esposito, ChemistrySelect, 2020,
Benessere, M. E. Cucciolito, A. De Santis, M. Di Serio, R.
Esposito, F. Ruffo, R. Turco, J. Am. Oil Chem. Soc., 2015, 92
701.
5, 1396. V.
Conflicts of interest
There are no conflicts to declare.
,
1
2
2
3
3
3
8 T. M. Luong, H.; Schriftman, D. Swern, D., J. Am. Oil Chem.
Soc., 1967, 44, 316.
Acknowledgements
9 E. Santacesaria, M. Ambrosio, A. Sorrentino, R. Tesser, M. Di
Serio, Catal. Today, 2003, 79–80, 59.
The authors would like to thank the French Ministry of National
Education, Higher Education and Research as well as the France-
Canada Research Fund for the funding of the PhD grant of NA.
The authors are also grateful to the Région Nouvelle Aquitaine
for the funding of this project through the FR CNRS INCREASE
0 A. Soutelo-Maria, J.-L.Dubois, J.-L. Couturier, G
. Cravotto,
Catalysts, 2018, , 464.
8
1 C. Venturello, R. Daloisio, J. C. J. Bart, M. A. Ricci, J. Mol. Catal.
1985, 32, 107-110
2 C. Venturello, R. Daloisio, J. Org. Chem., 1988, 53, 1553.
33 L. Carlos de la Garza, K. De Oliveira Vigier, G. Chatel, A.
3
707 (International Consortium on Eco-conception and
Moores, Green Chem., 2017, 19, 2855.
Renewable Resources), the chair TECHNOGREEN and FEDER.
3
3
4 F. Zhang, M. Chen, X. Jia, W. Xu, N. Shi, Process Saf. Environ.
Protection, 2019, 126, 1.
5 R. Noyori, M. Aoki, K. Sato, K., Chem.Comm., 2003, 16, 1977.
Notes and references
36 T. Strassner, Adv. Phys. Org. Chem., 2003, 38, 131.
37 A. Köckritz, A. Martin, Eur. J. Lipid Sci. Technol., 2008, 110,
1
2
3
4
5
6
7
8
9
1
L.C. Meher, D.V. Sagar, S. N. Naik,. Renew. Sust. Energ. Rev.,
006, 10, 248.
Z. Helwani, M. R. Othman, N. Aziz, W. J. N. Fernando, J. Kim,
Fuel Process. Technol., 2009, 90, 1502.
R. Jothiramalingam, M. K. Wang, Ind. Eng. Chem. Res., 2009,
48, 6162.
8
12.
2
3
8 A. Gharib, M. Jahangir, M. Roshani, N. Noroozi Pesyan, J.
Scheeren, Synth. React. Inorg. M., 2015, 45, 350.
D. Y. C. Leung, X. Wu, M. K. H. Leung, Appl. Energy, 2010, 87
083.
,
1
A. P. S. Chouhan, A. K. Sarma, Renew. Sust. Energ. Rev., 2011,
15, 4378.
M. E.Borges, L. Díaz, L., Renew. Sust. Energ. Rev., 2012, 16
839.
V. B. Borugadda, V. V. Goud, Renew. Sust. Energ. Rev., 2012,
6, 4763.
,
2
1
G. Santori, G. Di Nicola, M. Moglie, F. Polonara, F., Appl.
Energy, 2012, 92, 109.
P. J. Deuss, K. Barta, J. G. de Vries, J. G., Catal. Sci. Technol.,
2
014, 4, 1174–1196.
0 A. Behr, A. Westfechtel, J. P. Gomes, Chem. Eng. Technol.,
008, 31, 700.
11 V. Aggarwal, Org. Process Res. Dev., 2000,
12 B.-J.Kollbe Ahn, S. Kraft, S. Sun, J. Mater. Chem., 2011, 21,
498.
3 P. Metivier, M. Huet, L. Bernard, D. Charlemagne, WO Patent
000044704, 2000.
2
4
, 233–234.
9
1
1
2
4 F. E. Okieimen, C. Pavithran, I. O. Bakare, Eur J Lipid Sci
Technol., 2005, 107, 330.
15 K. Tsubone, Japanese Patent 2005213241, 2005.
6
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New Journal of Chemistry
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View Article Online
DOI: 10.1039/D0NJ02167A
Selective dihydroxylation of methyl oleate to methyl-9,10-
dihydroxysterate in the presence of a recyclable tungsten based catalyst
and hydrogen peroxide
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Nahla Araji, Gregory Chatel,* Audrey Moores,* François Jérôme and Karine De Oliveira Vigier*
Synthesis of methyl-9,10-dihydroxysterate with high yield (99%) from methyl oleate in the presence of
hydrogen peroxide and tungsten based catalyst
H PW O
Cs H PW O recycled
2,3 0,7 12 40
3
12 40