Recyclable process for sustainable adipic acid production in microemulsions

Article abstract of DOI:10.1016/j.tet.2010.06.093

Adipic acid is an important industrial intermediate for the manufacture of nylon-6,6. We propose a recyclable and environmentally friendly process for the oxidation of cyclohexene by hydrogen peroxide in microemulsions. These organized nano-structured media have been formulated in using the molecular economy principle. The main interests of the present work are the easy recovery of pure adipic acid and the reuse of the reaction media, what are promising for developing a future green industrial process.

Full text of DOI:10.1016/j.tet.2010.06.093

Tetrahedron 66 (2010) 7124e7128
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Tetrahedron
journal homepage: www.elsevier.com/locate/tet
Recyclable process for sustainable adipic acid production in microemulsions
Philippe Blach, Zebastian B o€ strom, Sophie Franceschi-Messant, Armand Lattes, Emile Perez , Isabelle
Rico-Lattes
*
Laboratoire des I.M.R.C.P. UMR5623 CNRS, Université Paul Sabatier, 118 route de Narbonne, Toulouse, 31062, France
a r t i c l e i n f o
a b s t r a c t
Article history:
Received 21 May 2010
Received in revised form 22 June 2010
Accepted 30 June 2010
Available online 6 July 2010
Adipic acid is an important industrial intermediate for the manufacture of nylon-6,6. We propose a re-
cyclable and environmentally friendly process for the oxidation of cyclohexene by hydrogen peroxide in
microemulsions. These organized nano-structured media have been formulated in using the molecular
economy principle. The main interests of the present work are the easy recovery of pure adipic acid and
the reuse of the reaction media, what are promising for developing a future green industrial process.
Ó 2010 Elsevier Ltd. All rights reserved.
Keywords:
Microemulsion
Adipic acid
Hydrogen peroxide
Oxidation
Sustainable chemistry
1. Introduction
and storage, high active oxygen content and low cost.7 However,
2 2
H O alone is rarely sufficient to achieve the conversion and cata-
8
Adipic acid is a very important industrial intermediate, since it is
used as a starting reagent in the preparation of nylon-6,6, a poly-
meric material used in carpet fibres, tyre reinforcement, automo-
bile parts, clothing and many other everyday life applications.
Adipic acid is currently industrially produced by the oxidation of
lysts are essential.
2 2
Oxidation of cyclohexene by H O typically involves epoxidation
of the double bond, its opening and transformation to a diol and
then a BaeyereVilliger oxidation and multiple hydrolysis steps
resulting in adipic acid (Scheme 2). The key step for this reaction in
1
9
a cyclohexanol/cyclohexanone mixture or cyclohexane with nitric
an aqueous medium is to bring all the reagents into close contact.
2
acid. Nitrous oxide, or N
2
O, emission generated during the syn-
thesis (0.3 tonne emitted per tonne of adipic acid produced) con-
3
tributes to global warming and ozone depletion. Therefore, the
development of an industrial process that is less damaging for the
4
environment is of crucial importance.
Adipic acid can be also obtained by oxidation of cyclohexene by
hydrogen peroxide in presence of a catalyst (Scheme 1).
Scheme 2. Pathway for the formation of adipic acid.
Scheme 1. Oxidation of cyclohexene with hydrogen peroxide.
5
Deng and co-workers described the synthesis of adipic acid in
a water emulsion by hydrogen peroxide oxidation of cyclohexene
without surfactant and under strong stirring. In this system, addi-
tion of an organic acid as ligand (co-catalyst) and severe reaction
Hydrogen peroxide (H
because it is relatively non-toxic and its decomposition leads to
benign by-products like water and oxygen.5,6
has several
advantages as an oxidant for industrial processes: easy handling
2 2
O ) is widely accepted as a green oxidant
H
2
O
2
ꢀ
ꢀ
conditions (20 h at 94 C following to 0 C overnight) were required
10
to obtain a good yield of pure adipic acid. Noyori and co-workers
described the use of a phase transfer agent (methyltrioctyl-
ammonium hydrogenosulphate) in water to produce adipic acid
with a good yield, but reuse of the system required an additional
*
Corresponding author. Tel.: þ33 561 557 382; fax: þ33 561 558 155; e-mail
address: perez@chimie.ups-tlse.fr (E. Perez).
0
040-4020/$ e see front matter Ó 2010 Elsevier Ltd. All rights reserved.
doi:10.1016/j.tet.2010.06.093

P. Blach et al. / Tetrahedron 66 (2010) 7124e7128
7125
amount of phase transfer agent to be effective. More recently, the
potential of transition metal-mesoporous materials as heteroge-
media for many organic reactions but there is still no industrial
process based on microemulsions, essentially because of the
difficulty to recover the products and to reuse the system.
11
neous systems have been described in water or organic solvent
but the long reaction time and/or the low adipic acid production
yield are not advantageous for an industrial process. Also, the use of
surfactant-type peroxotungstates or peroxomolybdates has been
studied but the reuse of these catalysts for a new reactional cycle
2
2
. Results and discussion
.1. Establishment of the microemulsions
(
in the perspective of an industrial process) is never descri-
12
bed. The main difficulty in water or hydrogen peroxide is the weak
contact between the hydrophobic and hydrophilic reagents. The
use of microemulsions as aqueous media for organic reactions is
a way to improve the compatibility between the different re-
agents13 and to overcome the use of polluting organic solvent. In
this paper, we present, for the first time, the use of hydrogen per-
oxide microemulsions as reaction media for the oxidation of
cyclohexene to adipic acid with hydrogen peroxide. The establish-
ment of the microemulsions zone, the reactivity in these media and
the reuse of the system (to provide a first approach for an industrial
process) will be presented and discussed.
Microemulsions are generally ternary systems comprising wa-
ter, oil, a surfactant and a co-surfactant like a medium chain alco-
19
hol. With a view to environment protection and a future
industrial process, we applied the principle of molecular economy,
and the microemulsion was mainly composed of the reagents:
cyclohexene as the oily phase and hydrogen peroxide as the
aqueous phase. Furthermore, we selected a special surfactant able
to form microemulsions without co-surfactants, which avoided the
short chain alcohols classically used but incompatible with an ox-
idation reaction. Benzalkonium chlorides (BenzCl) were selected
and have already been described for obtaining microemulsions
Microemulsions are transparent and thermodynamically stable
dispersions of oil and water or non aqueous structured polar sol-
24
without co-surfactants. These surfactants, also known as alkyl-
benzyldimethylammonium chlorides, are quaternary ammonium
14
vent (formamide, glycerol and their mixture with water) spon-
taneously formed by the addition of an amphiphile: a surfactant
and a co-surfactant (an amphiphile with a short chain like an al-
25
salts widely used as disinfectants, biocides and detergents. The
general structure of such surfactants is presented in (Scheme 3).
15
cohol, an acid or an amine). There are two types of micro-
emulsions according to the nature of the continuous phase (Fig. 1).
Their thermodynamic stability and their nanostructure are
two important characteristics that distinguish them from emul-
sions. Direct microemulsions are usually expressed as oil-in-
water microemulsions in which nanoscopic oil droplets
Scheme 3. General structure of benzalkonium chloride.
(
10e50 nm in diameter) are dispersed in water with the help of
Benzalkonium chlorides could be toxic for aquatic organisms,26
so their introduction in a process implies their control and strict
reuse. Also, in the aim of easily recovering pure adipic acid by
precipitation at room temperature and reusing the system, we fixed
the water phase at pH 1 by adding sulfuric acid.
In this study, we used a low-cost commercial mixture of BenzCl
containing 60 wt % of dodecyl (n¼1) and 40 wt % of tetrade-
cylbenzyldimethylammonium chloride (n¼2). In a first step, we
established a ternary phase diagram to determine the micro-
emulsion zones. Because of the stoichiometry of the reaction (4 mol
a surfactant and a co-surfactant. These microemulsions are very
suitable as reaction media for a sustainable development because
of their numerous properties; they allow organic synthesis in
water, specific localization of the reactants, interfacial orientation
of the molecules and increase of local concentrations and re-
action rate. Many chemical reactions have been studied in
16
17
microemulsion media: oligomerization of norbornene, photo-
amidation of olefin, catalytic hydrolysis of phosphate esters,
18
19
2
0
21
olefin oxidation, halogen nucleophilic substitution, mustard
gas oxidation,22 DielseAlder reaction
23
etc. Holmberg
13
has
demonstrated that microemulsions can be considered as an al-
ternative to biphasic systems with added phase transfer reagent.
Generally, microemulsions are described as versatile reaction
2 2
of H O per mol of cyclohexene), only the water-rich region of the
phase diagram was explored (direct microemulsions). For practical
reasons, hydrogen peroxide was replaced by water at pH 1 and the
Figure 1. The two types of microemulsion.

7126
P. Blach et al. / Tetrahedron 66 (2010) 7124e7128
ꢀ
titrations were performed at 25 C (see details in Experimental
section). We checked on several points, that we obtain the same
microemulsions, by replacing water by hydrogen peroxide.
The phase diagram obtained is shown in Figure 2.
Table 1
Influence of catalyst ratio
Catalyst ratio
Yield (%)a
1
3
6
.5 mol %
31
56
54
mol % (Initial)b
mol %
a
Based on adipic acid recovered.
b
3
mol % relative to cyclohexene.
As can be observed, in the selected microemulsion, the maxi-
mum yield of pure adipic acid (56%) was reached with a catalyst
ratio of 3 mol % relative to cyclohexene. An increase of this ratio did
not improve the yield of adipic acid, so we fixed the catalyst ratio at
3% for the subsequent experiments. Also, we varied the percentage
of sulfuric acid relative to the hydrogen peroxide, from 3 to 6 mol %,
with no significant increase in the adipic acid production yield.
In the chosen conditions, we followed the decrease of the re-
agents during the reaction by gas chromatography analysis for the
cyclohexene and by potassium permanganate titration for the hy-
drogen peroxide. The results are presented in Figure 3.
ꢀ
Figure 2. Ternary phase diagram (water/BenzCl/cyclohexene) at 25 C and pH 1. The
full dot (ꢃ) corresponds at the selected microemulsion mixture for the reaction.
Even without any co-surfactant, we obtained a large micro-
emulsion area with BenzCl. In some of these microemulsions, it was
possible to solubilize more than 20 wt % of cyclohexene but, in this
case, a large amount of surfactant (30 wt %) was required, which
drastically increased the viscosity (liquid crystal phases), limiting
their use as reaction media. Although the phase diagram was
ꢀ
established at 25 C, we checked that the microemulsions obtained
were optically clear, stable over time and in a large range of tem-
ꢀ
perature (5e100 C).
Once the ternary phase diagram had been established, we
selected a point of microemulsion to study the reactivity. This point
(
full dot on the phase diagram) was a trade-off among the following
Figure 3. Consumption of the reactants during the reaction.
criteria: a high concentration of cyclohexene with a relatively low
concentration of surfactant (to limit the viscosity of the micro-
emulsion) and the respect of the stoichiometry of the reaction. The
composition of this point was the following: cyclohexene 8 wt %
Conversion of the cyclohexene was completed in 2 h (limit of
detection by GC at 90% of conversion) and more than 7 h were
necessary to consume all the hydrogen peroxide. In accordance
with the mechanism which implies four stages of oxidation, the
cyclohexene (consummated during the first step of the process) is
transformed in 2 h, whereas 7 h are needed in order to consum-
mate the totality of the hydrogen peroxide.
ꢁ
1
(
0.975 mol L ); BenzCl 15 wt %; water 77 wt %.
2
.2. Oxidation of cyclohexene in the selected microemulsion
In the context of the development of a clean oxidation
Although the conversion of cyclohexene was total, the yield of
recovered adipic acid was only 56%. In fact, an additional amount of
adipic acid (equivalent to a yield of 20%) stayed soluble at room tem-
perature but could be recovered by cooling the solution to a low
process, we selected the non-polluting catalyst sodium tungstate,
Na WO , which contained no heavy metal. We also took advan-
tage of its anionic charge to associate it with the cationic
surfactant at the interface of the droplets. Although this catalyst
2
4
ꢀ
temperature (5 C). As we were looking for a reusable industrial pro-
is not very active, it is widely used for many oxidation reactions
cess, we neglected this low temperature step, favouring a cumulative
recoveryof theadipicacid atroomtemperature by reusing thesystem.
We investigated the influence of temperature and reaction time
on the adipic acid production yield. Several temperatures (room
in aqueous systems.2
7e30
By reaction with hydrogen peroxide,
sodium tungstate is transformed into sodium peroxotungstate,
the active catalyst able to oxidize cyclohexene at high tempera-
ꢀ
ture (Tꢂ70 C). Also, sodium tungstate is activated in acidic
ꢀ
temperature to 100 C) and reaction times (1.5e18 h) were tested
3
0
conditions like those in our microemulsion.
and the results are listed in Table 2.
Oxidation of cyclohexene was performed in the selected
microemulsion according to the following procedure: surfactant,
hydrogen peroxide (30 wt %), catalyst, cyclohexene and sulfuric
Table 2
Dependence of temperature and reaction time
ꢀ
acid were mixed (homogeneous solution) at 70 C for 18 h. After
ꢀ
Yield (%)a
Temperature ( C)
Reaction time (h)
reaction and cooling at room temperature, adipic acid precipitated
and was recovered by filtration. Pure adipic acid (analyzed by GC
chromatography and NMR) was obtained after washing the crude
solid with cold water. Several reaction parameters were optimized:
quantities of catalyst, sulfuric acid, temperature and reaction time.
Table 1 presents the effect on the reaction yield of varying the
quantity of catalyst.
2
7
7
90
100
0
0
0
18
5
18
5
0b
19
56
48
41
1.5
a
Based on adipic acid recovered.
No precipitation occurs.
b

P. Blach et al. / Tetrahedron 66 (2010) 7124e7128
7127
The parameter studied was the yield of pure adipic acid re-
covered. Firstly, it can be noted that no reaction occurred at room
ꢀ
ꢀ
temperature (20 C), confirming a minimum of 70 C to activate the
reaction. Secondly, good yields were obtained when the tempera-
ture was increased, which also considerably reduced the reaction
ꢀ
time. However, at 100 C and for a long reaction time (more than
3
h), by-products were formed in the precipitate, which led to
a supplementary step of purification not desirable for an industrial
process. These tests demonstrate the importance of the tempera-
ture on both the proposed reaction and adipic acid precipitation, so
it will have to specially taken into account in the framework of an
industrial process.
2
.3. Study of the recyclability of the system
Figure 4. Recycling studies of the process.
Our first results obtained in microemulsion demonstrate that it
is possible to obtain a good yield in the production of pure adipic
acid without using extreme conditions of stirring, high tempera-
tures or fastidious purification steps. In the objective of developing
an industrial process, we focused our attention on the recycling of
the system at the end of the reaction. After recovery of the adipic
acid by filtration, the remaining water solution (produced by re-
duction of hydrogen peroxide) contained unprecipitated adipic acid
cycles), which are comparable to the best yield presented in the
literature.
5
These results demonstrate, for the first time, that it is possible to
use a cyclohexene/hydrogen peroxide microemulsion to produce
pure adipic acid with very good yield without using extreme con-
ditions of temperature or long precipitation times. Within the
framework of an industrial application, this process could be ad-
vantageously modified (reduced energy cost) by replacing the
water evaporation step by an ultrafiltration step to concentrate the
(
due to its partial solubility, even at pH 1), surfactant, catalyst,
sulfuric acid and unreacted intermediates. The fact that water
remained caused two important problems. Firstly, if the water was
not removed and if we started a second reaction run, dilution by
addition of another volume of hydrogen peroxide shifted the
microemulsion point, reducing the efficiency of the system. Sec-
ondly, the dilution decreased the precipitation of adipic acid. We
bypassed these difficulties by introducing the steps illustrated in
31
surfactant in the water phase, as described in other processes.
. Conclusion
In summary, we have described, for the first time, an original
3
recyclable process for the synthesis of pure adipic acid by hydrogen
peroxide oxidation of cyclohexene in a microemulsion, with a very
good yield. In the context of an industrial approach, we used
microemulsions without co-surfactant and where practically all the
ingredients are also the reagents (molecular economy principle).
Microemulsion provides homogeneous media for close contact
between the reagents in the hydrogen peroxide phase, leading to
a better reactivity without the need for strong stirring or very high
temperatures. Thanks to the low pH used, the process leads to pure
adipic acid that can be recovered by simple filtration at room
temperature. The investigation of the system recyclability demon-
strated, (i) that it was possible to reuse the system for a new cycle
(Scheme 4).
(after adipic acid filtration and residual water evaporation) and (ii)
that an excellent yield could be obtained by cumulating the cycles.
These two points are essential in the perspective of an industrial
development of the process.
Scheme 4. Recyclability of the system.
After precipitation and recovery of the adipic acid (formed dur-
ing the first cycle), we checked the absence of peroxide in solution
hypochlorite test), then the majority of the water was evaporated at
4
4
. Experimental section
(
.1. Materials
low pressure until precipitation (solubilized adipic acid and sur-
factant) occurred. Then, the same amounts of hydrogen peroxide
and cyclohexene were introduced again and another reaction was
Benzalkonium chloride (95%, Fluka) and cyclohexene (99%,
ꢀ
SigmaeAldrich) were used without purification. Sulfuric acid
95e97%, SigmaeAldrich), sodium tungstate dihydrated (99%,
started in the same conditions as the first cycle (18 h at 70 C). After
(
this second cycle, adipic acid was again recovered by filtration after
cooling to room temperature and, after water removal by evapora-
tion, another reaction cycle was started. In that way, six consecutive
cycles were performed. The yields obtained (based on adipic acid
recovered) after each cycle are presented in Figure 4.
SigmaeAldrich), hydrogen peroxide (30 wt %, SigmaeAldrich), N,O-
bis(trimethylsilyl)acetamide (derivatization grade, SigmaeAldrich),
decanoic acid (99.5%, Fluka) and potassium permanganate (98%,
Lancaster) were used as received.
As we can see, the yield increased continuously with the con-
secutive cycles. Adipic acid did not totally precipitate at room
temperature but accumulated in the reaction medium cycle after
cycle, facilitating its precipitation and recovery. Furthermore, pos-
sible unreacted intermediates could be reoxidized during the dif-
ferent cycles, increasing the adipic acid production yield. The yield
rapidly reached extremely interesting values (up to 90% after five
4.2. Phase diagram determination
Each point was obtained by titration with cyclohexene of vari-
ous solutions of benzalkonium chloride/water (pH 1) at room
ꢀ
temperature (18 C). Addition of cyclohexene was stopped when
a turbid solution was obtained.

7
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P. Blach et al. / Tetrahedron 66 (2010) 7124e7128
2. (a) Usui, Y.; Sato, K. Green Chem. 2003, 5, 373e375; (b) Pai, Z. P.; Tolstikov, A. G.;
4
.3. Synthesis of adipic acid in microemulsion and
Berdnikova, P. V.; Kustova, G. N.; Khlebnikova, T. B.; Selivanova, N. V.; Shangina, A.
B.; Kostrovskii, V. G.Russ. Chem.Bull.,Int. Ed.2005, 54,1847e1854;(c)Yuan,Y.;Ji, H.;
Chen, Y.; Han, Y.; Song, X.; She, Y.; Zhong, R. Org. Process Res. Dev. 2004, 8, 418e420;
(d) Shimizu, A.; Tanaka, K.; Ogawa, H.; Matsuoka, Y.; Fujimori, M.; Nagamori, Y.;
Hamachi, H.; Kimura, K. Bull. Chem. Soc. Jpn. 2003, 76,1993e2001; (e) Castellan, A.;
Bart, J. C. J.; Cavallaro, S. Catal. Today 1991, 9, 237e254; (f) Belkhir, I.; Germain, A.;
Fajula, F.; Fache, E. Stud. Surf. Sci. Catal. 1997, 110, 577e584.
3. (a) Ravishankara, A. R.; Daniel, J. S.; Portmann, R. W. Science 2009, 326,
123e125; (b) Lapisardi, G.; Chiker, F.; Launay, F.; Nogier, J. P.; Bonardet, J. L.
Microporous Mesoporous Mater. 2005, 78, 289e295.
recyclability experiments
Benzalkonium chloride (5.25 g), hydrogen peroxide (30 wt %
solution, 26.95 g), sodium tungstate(410 mg), sulfuric acid (920 mg)
and cyclohexene (2.80 g) were introduced in a round-bottomed
flask equipped with a reflux condenser and a magnetic stirring bar.
The solution was heated at 70 C for 18 h. After cooling at room
temperature (with rapid stirring for the first 30 min), adipic acid
precipitated (precipitation started at 28 C) and was recovered by
filtration. The crude product was washed with cold water (5 mL) to
give a white powder. For recyclability studies, the filtrate was
evaporated at 70 C under reduced pressure (1 kPa), until solid re-
covery. Hydrogen peroxide and cyclohexene were introduced in the
ꢀ
4
. (a) Bolm, C.; Beckmann, O.; Dabard, O. A. G. Angew. Chem., Int. Ed. 1999, 38,
907e909; (b) Che, C.-M.; Yip, W.-P.; Yu, W.-Y. Chem.dAsian J. 2006, 1, 453e458.
. Deng, Y.; Wang, Z. M.; Chen, J. Green Chem. 1999, 1, 275e276.
. (a) Karimi, B.; Ghoreishi-Nezhad, M.; Clark, J. H. Org. Lett. 2005, 7, 625e628; (b)
Jiang, H.; Gong, H.; Yang, Z.; Zhang, X.; Sun, Z. React. Kinet. Catal. Lett. 2002, 75,
315e321.
ꢀ
5
6
ꢀ
7. (a) Phillips, A. M. F.; Romão, C. Eur. J. Org. Chem. 1999, 8, 1767e1770 1999; (b)
ꢀ
Saladino, R.; Bernini, R.; Neri, V.; Crestini, C. Appl. Catal., A 2009, 360, 171e176.
. (a) Higgs, D. E.; Nelen, M. I.; Detty, M. R. Org. Lett. 2001, 3, 349e352; (b)
Podgor ꢀs ek, A.; Zupan, M.; Iskra, J. Angew. Chem., Int. Ed. 2009, 48, 8424e8450;
same quantities and the reaction was restarted for 18 h at 70 C.
8
(
c) Gregori, F.; Nobili, I.; Bigi, F.; Maggi, R.; Predieri, G.; Sartori, G. J. Mol. Catal. A:
4
.4. GC analysis
Chem. 2008, 286, 124e127.
9
. (a) Ren, S.; Xie, Z.; Cao, L.; Xie, X.; Qin, G.; Wang, J. Catal. Commun. 2009, 10,
464e467; (b) Lee, S.-O.; Raja, R.; Harris, K. D. M.; Thomas, J. M.; Johnson, B. F. G.;
Sankar, G. Angew. Chem., Int. Ed. 2003, 42, 1520e1523.
The purity of the adipic acid was checked, after derivatization
with N,O-bis(trimethylsilyl)acetamide (decanoic acid was used as
an internal standard), by gas chromatography (Varian CP-3800)
with a flame-ionization detector and a MachereyeNagel Optima-1-
Accent-0.25 mm column (30 mꢄ0.25 mm). The GC settings were
1
0. Sato, K.; Aoki, M.; Noyori, R. Science 1998, 281, 1646e1647.
11. (a) Timofeeva, M. N.; Kholdeeva, O. A.; Jhung, S. H.; Chang, J. S. Appl. Catal., A
2008, 345, 195e200; (b) Lapisardi, G.; Chiker, F.; Launay, F.; Nogier, J. P.;
Bonardet, J. L. Catal. Commun. 2004, 5, 277e281.
12. Zhu, W.; Li, H.; He, X.; Zhang, Q.; Shu, H.; Yan, Y. Catal. Commun. 2008, 9,
ꢀ
programmed as follows: injector temperature 350 C (1 mL/min,
551e555.
ꢀ
split ratio: 10); detector temperature 350 C; column temperature
13. (a) Holmberg, K. Curr. Opin. Colloid Interface Sci. 2003, 8, 187e196; (b) Holm-
berg, K. Adv. Colloid Interface Sci. 1994, 51, 137e174.
ꢀ
1
50 C for 10 min.
14. (a) Lattes, A.; Rico, I. Colloids Surf. 1989, 35, 221e235; (b) Rico, I.; Lattes, A. Nouv.
J. Chim. 1984, 8, 429e431; (c) Saidi, Z.; Boned, C.; Peyrelasse, J. Prog. Colloid
Polym. Sci. 1992, 89, 156e159; (d) Peyrelasse, J.; Boned, C.; Saidi, Z. Prog. Colloid
Polym. Sci. 1989, 79, 263e269.
5. (a) Walsh, D. Microemulsions. Background, New Concepts, Applications, Perspec-
tives; Wiley-VCH: Germany, 2009; p 1; (b) Schwuger, M. J.; Stickdorn, K.;
Schm €a cker, R. Chem. Rev. 1995, 95, 849e864; (c) Paul, B. K.; Moulik, S. P. Curr.
4
.5. Derivatization procedure
0 mg of crude product, 20 mg of decanoic acid, 250 mg of N,O-
1
2
bis(trimethylsilyl)acetamide and 1 g of CHCl
6
3
were mixed for 1 h at
L of solution was analysed.
Sci. 2001, 80, 990e1001; (d) Texter, J.; Ziemer, P. Macromolecules 2004, 37,
ꢀ
0 C to room temperature, 1
m
5
841e5843.
6. Nardello-Rataj, V.; Caron, L.; Borde, C.; Aubry, J.-M. J. Am. Chem. Soc. 2008, 130,
4914e14915.
7. Eychenne, P.; Perez, E.; Rico, I.; Bon, M.; Lattes, A.; Moisand, A. Colloid Polym. Sci.
993, 271, 1049e1054.
18. Gautier, M.; Rico, I.; Lattes, A. J. Org. Chem. 1990, 55, 1500e1503.
9. Burnside, B. A.; Szafraniec, L. L.; Knier, B. L.; Durst, H. D.; Mackay, R. A.; Longo, F.
1
1
4
.6. Hydrogen peroxide titration
1
1
A 2.10 2 M solution of potassium permanganate was obtained by
ꢁ
1
dissolution of 3.4 g of solid potassium permanganate in a beaker
containing 1 L of deionized water. This solution was refluxed for
R. J. Org. Chem. 1988, 53, 2009e2011.
2
0. Alandis, N.; Rico, I.; Lattes, A. Bull. Soc. Chim. Fr. 1989, 2, 252e255.
21. H
a€ ger, M.; Currie, F.; Holmberg, K. Colloids and Surfaces A: Physicochem. Eng.
2
0 min and filtered. The exact concentration was determined by ti-
trationwith potassium oxalate (0.1 g dissolved in 20 mL of water with
mL of sulfuric acid). Consumption of hydrogen peroxide was mon-
Aspects 2004, 250, 163e170.
2. (a) Gonzaga, F.; Perez, E.; Rico-Lattes, I.; Lattes, A. New J. Chem. 2001, 25,
51e155; (b) Fallis, I. A.; Griffiths, P. C.; Cossgrove, T.; Dreiss, C. A.; Govan, N.;
2
5
1
itored by taking 0.1 g of crude diluted in 20 mL of water with 5 mL of
sulfuric acid and titrated until a persistent colouration was obtained.
Heenan, R. K.; Holden, I.; Jenkins, R. L.; Mitchell, S. F.; Notman, S.; Platts, J. A.;
Tatchell, T. J. Am. Chem. Soc. 2009, 131, 9746e9755.
3. Lattes, A.; De Savignac, A.; Ahmad-Zadeh Samii, A. Tetrahedron 1987, 43,
2
1725e1735.
2
4. Mayhan, K.G.; Coulter, S.L.; Oviatt, C.L.H. WO 9312774, 1993.
Acknowledgements
2
5. (a) Kuca, K.; Marek, J.; Stodulka, P.; Musilek, K.; Hanusova, P.; Hrabinova, M.;
Jun, D. Molecules 2007, 12, 2341e2347; (b) Verall, R. E.; Milioto, S.; Zana, R. J.
Phys. Chem. 1988, 92, 3939e3943; (c) Para, B. V.; Núñez, O.; Moyano, E.; Gal-
ceran, M. T. Electrophoresis 2006, 27, 2225e2232.
The authors gratefully thank the French ANR CP2D for the fi-
nancial support.
2
6. (a) Pérez, P.; Fernández, E.; Beiras, R. Water, Air, Soil Pollut. 2009, 201, 319e330;
(b) Ferrer, I.; Furlong, E. T. Environ. Sci. Technol. 2001, 35, 2583e2588.
2
2
2
7. Murahashi, S.-I.; Imada, Y.; Ohtake, H. J. Org. Chem. 1994, 59, 6170e6172.
8. Sapurina, I.; Fedorova, S.; Stejskal, J. Langmuir 2003, 19, 7413e7416.
9. (a) Lane, B. S.; Burgess, K. Chem. Rev. 2003, 103, 2457e2474; (b) Xia, Q.-H.; Ge,
H.-Q.; Ye, C.-P.; Liu, Z.-M.; Su, K.-X. Chem. Rev. 2005, 105, 1603e1662; (c)
Venturello, C.; D’Aloisio, R. J. Org. Chem. 1988, 53, 1553e1557.
References and notes
1
. (a) Cavani, F.; Teles, J. H. ChemSusChem 2009, 2, 508e534; (b) Thomas, J. M.;
Raja, R.; Sankar, G.; Johnson, B. F. G.; Lewis, D. W. Chem.dEur. J. 2001, 7,
972e2978; (c) Li, H.; Zhu, W.; He, X.; Zhang, Q.; Pan, J.; Yan, Y. React. Kinet.
2
3
0. Venturello, C.; Ricci, M. J. Org. Chem. 1986, 51, 1599e1602.
Catal. Lett. 2007, 92, 319e327; (d) Bonnet, D.; Ireland, T.; Fache, E.; Sinomato, J.-P.
Green Chem. 2006, 8, 556e559.
31. Lambert, A.; Plucinski, P.; Kozhevnikov, I. V. Chem. Commun. 2003, 714e715.