Substituted Phthalic Anhydrides from Biobased Furanics: A New Approach to Renewable Aromatics

Article abstract of DOI:10.1002/cssc.201500511

A novel route for the production of renewable aromatic chemicals, particularly substituted phthalic acid anhydrides, is presented. The classical two-step approach to furanics-derived aromatics via Diels-Alder (DA) aromatization has been modified into a three-step procedure to address the general issue of the reversible nature of the intermediate DA addition step. The new sequence involves DA addition, followed by a mild hydrogenation step to obtain a stable oxanorbornane intermediate in high yield and purity. Subsequent one-pot, liquid-phase dehydration and dehydrogenation of the hydrogenated adduct using a physical mixture of acidic zeolites or resins in combination with metal on a carbon support then allows aromatization with yields as high as 84 % of total aromatics under relatively mild conditions. The mechanism of the final aromatization reaction step unexpectedly involves a lactone as primary intermediate.

Full text of DOI:10.1002/cssc.201500511

DOI: 10.1002/cssc.201500511
Communications
Substituted Phthalic Anhydrides from Biobased Furanics:
A New Approach to Renewable Aromatics
[a]
[a]
[c]
Shanmugam Thiyagarajan,[a, b] Homer C. Genuino, Michał Sliwa, Jan C. van der Waal,
´
Ed de Jong,*[c] Jacco van Haveren,[b] Bert M. Weckhuysen,[a] Pieter C. A. Bruijnincx,*[a] and
Daan S. van Es*[b]
A novel route for the production of renewable aromatic chemi-
cals, particularly substituted phthalic acid anhydrides, is pre-
sented. The classical two-step approach to furanics-derived ar-
omatics via Diels–Alder (DA) aromatization has been modified
into a three-step procedure to address the general issue of the
reversible nature of the intermediate DA addition step. The
new sequence involves DA addition, followed by a mild hydro-
genation step to obtain a stable oxanorbornane intermediate
in high yield and purity. Subsequent one-pot, liquid-phase de-
hydration and dehydrogenation of the hydrogenated adduct
using a physical mixture of acidic zeolites or resins in combina-
tion with metal on a carbon support then allows aromatization
with yields as high as 84% of total aromatics under relatively
mild conditions. The mechanism of the final aromatization re-
action step unexpectedly involves a lactone as primary inter-
mediate.
adduct that can, in principle, be subsequently dehydrated to
the desired aromatic compound. Efficient coupling of the DA
addition and the acid-catalyzed dehydration is often critical as
the intermediate adduct is unstable and prone to retro-Diels–
Alder reaction. Early studies by Diels himself, as well as others,
already showed that phthalic acid anhydride and its derivatives
can be obtained via this DA aromatization route.[3]
Newman et al. later reported that concentrated H2SO4 in sul-
folane works best for the synthesis of 3-methylphthalic anhy-
dride starting from 2-methylfuran and maleic anhydride, ob-
taining a yield of 66%. This reaction had to be run at À558C
because of unfavorable competition between the retro-DA and
acid-catalyzed reactions at higher, more industrially relevant
temperatures.[4] Toste et al. also performed the DA addition of
2,5-dimethylfuran (DMF) and acrolein at a temperature of
À558C, owing to the limited stability of the adduct. To further
suppress retro-DA activity, they also included an intermediate
oxidation step converting the aldehyde group in the DA
adduct to a carboxylic acid. Subsequent dehydration and final-
ly decarboxylation afforded p-xylene, albeit in a moderate
overall yield (34%).[5] Mahmoud et al. also noted the inherent
difficulties associated with the stability of DA adducts and the
competition between the retro-DA and acid-catalyzed dehydra-
tion reactions. An elegant strategy was developed to address
this issue, using methanesulfonic acid in combination with
acetic anhydride at 808C to efficiently aromatize various furan-
based DA adducts to (substituted) phthalic anhydrides.[6]
Most of the efforts into furanics-based aromatization routes
are actually focused on p-xylene production, being the drop-in
precursor to TA. Heterogeneous solid acid catalysts such as
zeolites (e.g., H-Y, H-ZSM-5, and H-Beta) are used to convert
DMF and ethylene to p-xylene in high yield, with H-Beta per-
forming best in reactions run in heptane as solvent at a reac-
tion temperature of 2508C and typical ethylene pressures of
62 bar.[7] Tungstated zirconia and niobic acid also efficiently
catalyze this reaction, showing higher turnover frequencies
than H-Y under the applied conditions.[8]
Aromatic di- and tricarboxylic acids such as phthalic acid (PA),
isophthalic acid (IPA), terephthalic acid (TA), and trimellitic acid
(TMA) are used in large amounts for the industrial production
of polyester fibers and films, alkyd resins and paints, and plasti-
cizers for PVC products.[1] The diminishing reserves and
changes in the composition of fossil resources have led to in-
creased efforts aimed at the production of such aromatic car-
boxylic acids from renewable resources, biomass in particular.[2]
One particularly attractive route to such ‘drop-in’ renewable ar-
omatics that is currently being actively explored makes use of
a Diels–Alder (DA) addition between a biomass-derived furanic
diene and an appropriate dienophile to give an oxabicyclic
´
[a] Dr. S. Thiyagarajan, Dr. H. C. Genuino, Dr. M. Sliwa,
Prof. Dr. B. M. Weckhuysen, Dr. P. C. A. Bruijnincx
Inorganic Chemistry and Catalysis
Debye Institute for Nanomaterials Science
Utrecht University
Universiteitsweg 99, 3584 CG Utrecht (The Netherlands)
E-mail: p.c.a.bruijnincx@uu.nl
[b] Dr. S. Thiyagarajan, Dr. J. van Haveren, Dr. D. S. van Es
Food & Bio-based Research
Pacheco et al. aimed to avoid the reductive hydrodeoxyge-
nation of 5-hydroxymethylfurfural (HMF) to DMF and per-
formed the DA/aromatization reaction of several oxidized de-
rivatives of HMF with ethylene over Sn-Beta at 1908C in diox-
ane, yielding the aromatic products in moderate yields and se-
lectivities.[9] The resulting DA-aromatization products can, in
principle, be further oxidized to TA.
Wageningen University and Research Centre
P.O. Box 17, 6700 AA Wageningen (The Netherlands)
E-mail: daan.vanes@wur.nl
[c] Dr. J. C. van der Waal, Dr. E. de Jong
Avantium Chemicals
Zekeringstraat 29, 1014 BV Amsterdam (The Netherlands)
E-mail: ed.dejong@avantium.com
The examples discussed above illustrate the problems that
result from the adducts’ tendency for retro-DA, thus requiring
Supporting Information for this article is available on the WWW under
http://dx.doi.org/10.1002/cssc.201500511.
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reactions to be run either at very low temperatures or at high
ethylene gas pressures. The aim of this study is to develop
a novel approach to the synthesis of furanics-derived, renewa-
ble aromatics, especially towards (substituted) phthalic acid an-
hydrides. The new route specifically addresses the challenges
resulting from the chemical instability of the DA adduct inter-
mediate. In particular, a three-step procedure consisting of DA
addition, hydrogenation, and finally aromatization of the hy-
drogenated DA adduct has been developed (Scheme 1). The
Scheme 1. New route to renewable (substituted) phthalic anhydrides via
Diels–Alder addition, hydrogenation, and aromatization of furan derivatives
with maleic anhydride.
strategy of hydrogenating the double bond in the DA adduct
eliminates the possibility of retro-DA reaction at the elevated
temperatures required for aromatization. Using a catalyst
system capable of both dehydration and dehydrogenation, the
desired aromatic compound can then be obtained in good
overall yields and selectivities.
Figure 1. Stability comparisons of the Diels–Alder (DA) adduct of methylfur-
an and maleic anhydride (1) and the corresponding hydrogenated DA
adduct (2): (a) loss of 1 by retro-DA in d-toluene as function of temperature
as determined by H NMR; (b) Weight loss determined by TGA analysis
under N2 atmosphere.
1
The new route is first demonstrated for the combination of
2-methylfuran (2-MF) and maleic anhydride (MA), both of
which can be readily obtained from renewable resources.[10]
The exo-isomer of the DA adduct 1 was obtained in near quan-
titative yield by reacting MA with 1.2 equiv of 2-MF (see Sup-
porting Information). Attempts to aromatize 1 in the presence
of an acid catalyst failed to produce any aromatic compounds;
in fact, the reaction over H-Y (SiO2/Al2O3 ratio of 5.2) in toluene
at 1508C gave a tarlike material. The adduct is almost fully lost
to retro-DA to again produce MA and 2-MF, of which the latter
is known to undergo acid-catalyzed self-polymerization result-
ing in the formation dimers and oligomers.[7b] This prompted
us to study the stability of 1 in detail as a function of time,
temperature, and solvent. Rapid retro-DA was observed in all
solvents tested, with decomposition already being observed at
temperatures as low as 208C. The loss of the adduct 1 to
retro-DA as function of temperature studied by thermogravi-
metric analysis (TGA) and 1H NMR is depicted in Figure 1,
showing different onset temperatures for retro-DA in solution
and the solid state. Details regarding the stability of the
adduct and kinetics of retro-DA can be found in the Support-
ing Information.
the scale of the reaction, yielding 2 as a colorless, crystalline
solid in near-quantitative yield (Scheme 2). Variable tempera-
ture NMR and TGA analyses of 2 (Figure 1) showed this new in-
termediate to be more thermally stable. The first indication of
the desired aromatization of 2 was obtained from a reaction
using a physical mixture of a solid acid (H-Y, SiO2/Al2O3 ratio of
5.2, 10 wt% w.r.t. the substrate) and a dehydrogenation cata-
lyst (10 wt% Pd/C, 3 wt% w.r.t. the substrate) in toluene at
1508C. A low 4% yield of the desired aromatic product 3-
methylphthalic anhydride 4 was detected together with three
other products, that is, m-toluic acid 5a (2%), 3-methylcyclo-
hexenedicarboxylic acid anhydride (transfer hydrogenation
product) 6 (3%), and, unexpectedly, the g-lactone 3 (23%) at
50% conversion (see Supporting Information Table S1, entry 1).
The influence of temperature, time, and catalyst loading on ar-
omatization efficiency was subsequently assessed. Experiments
with the individual catalysts (either zeolite or Pd/C catalyst)
provided insights into the reaction network. While the use of
only the 10 wt% Pd/C catalyst did not give any conversion of
2 at 2008C (Table S1, entry 5), the use of zeolite H-Y alone re-
sulted in 50% conversion after 24 h at 1508C in toluene. In the
latter reaction, g-lactone 3 is predominantly obtained (45% se-
lectivity), as well as minor amounts of 4 and the byproducts
1 can be very easily and efficiently hydrogenated over Pd/C
in THF at room temperature using 5–80 bar H2 depending on
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Scheme 2. Three-step Diels–Alder addition, hydrogenation and aromatization strategy to produce 2-methylfuran-derived 3-methylphthalic anhydride and
ortho/meta-toluic acids; the tandem-catalyzed final step requires H-Y and Pd/C and involves lactone 3 as primary intermediate.
5a and 6 (Table S1, entry 1). Increasing the amount of H-Y
from 10 wt% to 50 wt% further increased the selectivity to-
wards the g-lactone 3 to 57% (Table S1, entry 2). The methyl
ester of 3, a highly interesting multifunctional building block in
its own right, has been reported previously using a five-step
route starting from 2-MF.[11] Increasing the temperature from
1508C to 2008C using 10 wt% H-Y resulted in a further shift to
the aromatic product 4, now obtained with 33% selectivity at
2008C, accompanied by a concomitant decrease in selectivity
to the g-lactone (3) (Table 1, entry 1).
The use of a Pd/C+H-Y physical mixture at 2008C resulted
in full conversion of the the starting material after 24 h, yield-
ing 56% of the desired 3-methylphthalic anhydride 4 with
a
75% cumulative selectivity towards aromatics (Table 1,
Figure 2. Conversion of hydrogenated DA adduct 2, yields of g-lactone 3, 3-
methylphthalic anhydride 4, o- and m-toluic acid 5a+5b, and total aromat-
ics yield as a function of time.
entry 2). Under these conditions, g-lactone 3 is not observed
anymore, while m-toluic acid 5a has become the most promi-
nent byproduct at 17% yield. Molecular hydrogen was (qualita-
tively) detected by GC analysis of the headspace of the reac-
tion. Monitoring the conversion as function of time (Figure 2)
showed the g-lactone 3 to be a primary intermediate, gradual-
ly being further aromatized (see Table S1, entries 6–9). Increas-
ing the weight loading of H-Y to 30 wt% or 50 wt% (Table 1,
entries 3 and 4) did not result in any significant changes; the
transfer hydrogenation product 6 was no longer detected at
higher loadings of H-Y, however.
Two organic solid acids were also tested at 1758C (Table 1,
entries 8 and 9). The highly acidic Nafion resin (NR50) shows
higher conversion and selectivities to the desired aromatics
than H-Y at this particular temperature (Table 1, entries 7–9),
while the performance of the acidic ion exchange resin Amber-
lyst 70 is more comparable to H-Y (Table 1, entry 7). The lac-
tone is detected in 10-15% with both types of acid catalysts.
Notably, the organic solid acids produce markedly lower
amounts of the decarboxylated by-products 5a and 5b.
A series of commercial (5 wt%) metal on carbon catalysts, in-
cluding Pd/C (benchmark), Pt/C, Ru/C, Rh/C, were tested as de-
hydrogenation catalyst (Table 1, entries 10–13). The results
show that Pt/C performs best, giving the highest selectivity to-
wards aromatics.
Variation of the zeolite showed that H-VUSY (SiO2/Al2O3
mole ratio: 11.5) gave a higher yield (84%) in aromatics than
H-Y at full conversion (mole balance of 90%), while H-Beta
(SiO2/Al2O3 mole ratio: 25) showed a significantly lower conver-
sion (55%) and a high selectivity towards the g-lactone 3
under the standard conditions (Table 1, entries 5 and 6). The 3-
methylphthalic anhydride yield of 59% can be compared to
earlier reports showing yields of 48% or 66% from 1 and
methanesulfonic acid[6] or conc. H2SO4,[4] respectively. The total
aromatics yield of 84% is similar to the 87% yield of PA and
phthalic anhydride that was recently reported by Mahmoud
et al.[6]
Furan and 2,5-dimethylfuran were also investigated as diene
in the aromatization reaction (Table 1, entries 14 and 15). For
both substrates, the hydrogenated adduct can again be readily
obtained in excellent yields (see experimental section in the
Supporting Information). The hydrogenated DA adduct of
furan and maleic anhydride is much less reactive than 2, giving
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Table 1. Tandem-catalytic aromatization of hydrogenated Diels–Alder adducts.[a]
Solid acid
Metal on carbon
T
[oC]
Conversion
[mol%][c]
Mole balance
[%][d]
Entry
Molar yield [%] (Selectivity [%])[c]
catalyst [wt%][b] (3 wt%)[b]
[e]
[f]
1
2
3
4
5
6
7
8
H-Y (10%)
H-Y (10%)
H-Y (30%)
H-Y (50%)
H-VUSY (10%)
H-Beta (10%)
H-Y (10%)
Amb-70 (10%)
Nafion (10%)
H-Y (10%)
H-Y (10%)
H-Y (10%)
H-Y (10%)
H-Y (10%)
H-Y (10%)
–
200 X=Me; Y=H
64
15 (23)
22 (33)
56 (56)
59 (59)
56 (56)
59 (59)
22 (42)
29 (44)
31 (42)
48 (52)
48 (54)
52 (60)
29 (53)
28 (50)
10 (41)
67 (67)
4 (6)
17 (17)
19 (19)
18 (18)
19 (19)
6 (13)
10 (15)
2 (2)
5 (5)
–
3 (4)
10 (10)
–
80
85
80
76
90
98
87
82
79
88
90
98
99
90
79
Pd/C[g]
Pd/C[g]
Pd/C[g]
Pd/C[g]
Pd/C[g]
Pd/C[g]
Pd/C[g]
Pd/C[g]
Pd/C[h]
Pt/C[h]
Ru/C[h]
Rh/C[h]
Pd/C[g]
Pd/C[g]
200 X=Me; Y=H 100
200 X=Me; Y=H 100
200 X=Me; Y=H 100
200 X=Me; Y=H 100
200 X=Me; Y=H
175 X=Me; Y=H
175 X=Me; Y=H
175 X=Me; Y=H
200 X=Me; Y=H
200 X=Me; Y=H
200 X=Me; Y=H
200 X=Me; Y=H
200 X=Y=H
–
–
–
2 (2)
2 (2)
2 (2)
6 (6)
4 (9)
2 (3)
4 (5)
3 (4)
2 (2)
[f]
[f]
[f]
[f]
[f]
[f]
–
–
6 (6)
–
[f]
55
66
74
92
88
87
56
56
24
100
21 (40)
10 (15)
15 (19)
11 (12)
6 (6)
–
18 (32)
17 (31)
–
2 (3)
4 (5)
4 (5)
2 (2)
2 (2)
2 (4)
2 (5)
–
9
10
11
12
13
14
15
18 (20)
23 (26)
5 (10)
[f]
[f]
–
–
–
[f]
[f]
8 (16)
[f]
[f]
[f]
[f]
[f]
4 (17)[i]
12 (12)[j]
–
[f]
200 X=Y=Me
–
–
–
[a] Conditions: 1.5 g scale, 24 h in toluene, catalyst(s) and temperature are indicated in the table. [b] wt% relative to substrate. [c] Calculated by q-NMR
using 1,4-dinitrobenzene as internal standard. [d] Mole balance is determined from the total number of moles calculated from the crude mixture after the
reaction by NMR analysis. [e] No catalyst was added. [f] Not observed. [g] 10 wt% metal on carbon. [h] 5 wt% metal on carbon. [i] Benzoic acid. [j] p-Xylene.
only 24% conversion after 24 h under the standard reaction
conditions (2008C, 10 wt% H-Y and 3 wt% Pd/C), but the se-
lectivity to the aromatic products is nonetheless similar. In con-
trast, the hydrogenated adduct obtained of 2,5-dimethylfuran
and maleic anhydride was readily converted in 24 h under
standard conditions, giving only the desired dimethyl phthalic
anhydride and p-xylene as the only products (i.e., no 2,5-dime-
thylbenzoic acid is detected). The difference in activity be-
tween the three different hydrogenated DA adducts is not un-
expected, given that the ease of the acid-catalyzed ring open-
ing of the oxanorbornane ring will depend on the furan substi-
tution pattern, with ipso electron-releasing substituents (i.e.,
the methyl group) able to stabilize the positive charge devel-
oping on the carbon in the transition state.
merization/dehydrogenation of the lactone or hydrolysis of 4
by any of the water formed during reaction. Complete conver-
sion was observed for this compound, with 88% of the sub-
strate being simply converted to the anhydride 4 (Table 2,
entry 3); no decarboxylation to 5a or 5b was observed,
though. Finally, the toluic acids were found to give conversions
of 9% and 11 %, respectively (Table 2, entry 4 and 5), but no
compounds other than the starting compounds could be de-
1
tected by H NMR. Toluene could be formed by decarboxyla-
tion of the toluic acids, but this product cannot be detected as
the reactions were performed in toluene as the solvent. Taken
together, these results do suggest that decarboxylation occurs
prior to the aromatization step.
Based on the results shown in Tables 1 and 2 and Table S1, it
is clear that the first step of the tandem-catalyzed conversion
consists of the isomerization of the hydrogenated adduct to
give the lactone, a reaction that requires only the acid catalyst.
Aromatization, decarboxylation, and transfer hydrogenation do
occur with only the zeolite present, but to a limited extent.
Indeed, a dehydrogenation catalyst is required to efficiently
convert the lactone and to give high yields of aromatic prod-
ucts. It should be noted in this sense that the addition of the
dehydrogenation catalyst enhanced both the aromatization
and the decarboxylation reaction. So far this new method was
found to be applicable to dienes such as furan, 2-methyl furan
and 2,5-dimethylfuran in combination with maleic anhydride.
Possible extension of the substrate scope to other dienophiles
such as methyl acrylate, fumaronitrile, as well as maleimides is
the subject of a mechanistic study that focuses on the role
and importance of the lactone intermediate in the new route
and will be reported separately.
To obtain more insight into the reaction mechanism, the ob-
served aromatic products and possible intermediates were also
subjected to the typical reaction conditions (Table 2). First, the
g-lactone 3 was purposely synthesized according to the reac-
tion conditions described in Table S1, entry 2 and purified by
distillation. Using the g-lactone 3 as substrate resulted in com-
plete conversion, giving the anhydride 4 in 52% and the de-
carboxylated products, m-toluic acid 5a and o-toluic acid 5b
in 28% and 4%, respectively (Table 2, entry 1). This again em-
phasises the key role the lactone plays as primary intermediate
and furthermore shows that all aromatic products obtained are
in fact derived from this intermediate. The desired product 4
itself is highly stable in the presence of H-Y and Pd/C at 2008C
for 24 h, and was quantitatively recovered after the reaction
(Table 2, entry 2). We also tested the reactivity of 3-methyl-
phthalic acid, as this compound could be considered a precur-
sor to the toluic acids and can potentially be formed by iso-
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Table 2. Reactivity of possible intermediates, including lactone 3 and the aromatic products 4, 5a, and 5b under typical aromatization conditions.[a]
Entry
Starting
material
Conversion
[mol%][b]
Molar yield [%][b] (Selectivity [%])[c]
Mole
balance [%][d]
[e]
[e]
1
100
52 (52)
28 (28)
4 (4)
–
–
84
[e]
[e]
[e]
[e]
[e]
[e]
[e]
2
3
0
100 (100)
88 (88)
–
–
–
–
–
–
–
100
88
[e]
100
–
[e]
[e]
[e]
[e]
[e]
[e]
4
5
11
9
–
89
–
–
–
–
–
89
91
[e]
[e]
–
-
91
[a] Conditions: 1.5 g scale, H-Y (10 wt%), Pd/C (3 wt%) at 2008C for 24 h in toluene. [b and c] Calculated by q-NMR using 1,4-dinitrobenzene as internal
standard. [d] Mole balance is determined from the total number of moles calculated from the crude mixture after the reaction by NMR analysis. [e] Not ob-
served.
[1] G. Wypych, Handbook of Plasticizers, 1st ed., ChemTec Publishing and
William Andrew Inc., Toronto-New York, 2004.
[2] a) Y. Tachibana, S. Kimura, K.-I. Kasuya, Sci. Rep. 2015, 5, 8249; b) D. I.
In conclusion, it is successfully demonstrated that renewable
substituted phthalic anhydrides can be prepared in good yield
starting from furan-derived DA adducts. A hydrogenation step
Collias, A. M. Harris, V. Nagpal, I. W. Cottrell, M. W. Schultheis, Ind. Bio-
is included to stabilize the DA adducts and to prevent any
retro-DA reactivity during aromatization. By doing so, the over-
all aromatics yield can be dramatically enhanced for the diene/
dienophile combinations studied. The novel route makes use
of a physical mixture of two types of solid catalysts, zeolites
(H-Y or H-VUSY) and Pd/C. A lactone is identified as the pri-
mary intermediate of the reaction and found to be an impor-
tant precursor to all aromatic products formed in the process.
The new route and tandem catalytic final step is thought to be
more generally applicable and can also serve as a solution for
other DA-aromatization reactions limited by the thermal stabili-
ty of the intermediate adduct.
technol. 2014, 10, 91–105.
[3] a) O. Diels, K. Alder, Justus Liebigs Ann. Chem. 1931, 490, 243–257;
b) M. G. V. Campen, J. R. Johnson, J. Am. Chem. Soc. 1933, 55, 430–431.
[4] a) M. S. Newman, B. T. Lord, J. Am. Chem. Soc. 1944, 66, 733–735;
b) M. S. Newman, S. Blum, J. Med. Chem. 1964, 7, 466–468; c) M. S.
Newman, V. Lee, J. Org. Chem. 1977, 42, 1478–1479.
[5] M. Shiramizu, F. D. Toste, Chem. Eur. J. 2011, 17, 12452–12457.
[6] E. Mahmoud, D. A. Watson, R. F. Lobo, Green Chem. 2014, 16, 167–175.
[7] a) C. L. Williams, C.-C. Chang, P. Do, N. Nikbin, S. Caratzoulas, D. G. Vla-
chos, R. F. Lobo, W. Fan, P. J. Dauenhauer, ACS Catal. 2012, 2, 935–939;
b) C.-C. Chang, S. K. Green, C. L. Williams, P. J. Dauenhauer, W. Fan,
Green Chem. 2014, 16, 585–588.
[8] D. Wang, C. M. Osmundsen, E. Taarning, J. A. Dumesic, ChemCatChem
2013, 5, 2044–2050.
[9] J. J. Pacheco, M. E. Davis, Proc. Natl. Acad. Sci. USA 2014, 111, 8363–
8367.
[10] a) N. Alonso-Fagfflndez, M. L. Granados, R. Mariscal, M. Ojeda, Chem-
SusChem 2012, 5, 1984–1990; b) F. Dong, Y. Zhu, H. Zheng, Y. Zhu, X. Li,
Y. Li, J. Mol. Catal. A 2015, 398, 140–148.
Acknowledgements
[11] T. Kato, T. Suzuki, N. Ototani, H. Maeda, K. Yamada, Y. Kitahara, J. Chem.
Soc. Perkin Trans. 1 1977, 206–210.
This work is part of research program Technology Areas for Sus-
tainable Chemistry (TASC), which is partly financed by the Nether-
lands Organization for Scientific Research (NWO).
Received: April 15, 2015
Keywords: aromatics · aromatization · Diels-Alder reaction ·
furans · hydrogenation
Revised: June 17, 2015
Published online on July 31, 2015
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