Bioderived Muconates by Cross-Metathesis and Their Conversion into Terephthalates

Article abstract of DOI:10.1002/cssc.201701874

Polyethylene terephthalate that is 100 % bioderived is in high demand in the market guided by the ever-more exigent sustainability regulations with the challenge of producing renewable terephthalic acid remaining. Renewable terephthalic acid or its precursors can be obtained by Diels–Alder cycloaddition and further dehydrogenation of biomass-derived muconic acid. The cis,cis isomer of the dicarboxylic acid is typically synthesized by fermentation with genetically modified microorganisms, a process that requires complex separations to obtain a high yield of the pure product. Furthermore, the cis isomer has to be transformed into the trans,trans form and has to be esterified before it is suitable for terephthalate synthesis. To overcome these challenges, we investigated the synthesis of dialkyl muconates by cross-metathesis. The Ru-catalyzed cross-coupling of sorbates with acrylates, which can be bioderived, proceeded selectively to yield diester muconates in up to 41 % yield by using very low catalyst amounts (0.5–3.0 mol %) and no solvent. In the optimized procedure, the muconate precipitated as a solid and was easily recovered from the reaction medium. Analysis by GC–MS and NMR spectroscopy showed that this method delivered exclusively the trans,trans isomer of dimethyl muconate. The Diels–Alder reaction of dimethyl muconate with ethylene was studied in various solvents to obtain 1,4-bis(carbomethoxy)cyclohexene. The cycloaddition proceeded with very high conversions (77–100 %) and yields (70–98 %) in all of the solvents investigated, and methanol and tetrahydrofuran were the best choices. Next, the aromatization of 1,4-bis(carbomethoxy)cyclohexene to dimethyl terephthalate over a Pd/C catalyst resulted in up to 70 % yield in tetrahydrofuran under an air atmosphere. Owing to the high yield of the reaction of dimethyl muconate to 1,4-bis(carbomethoxy)cyclohexene, no separation step was needed before the aromatization. This is the first time that cross-metathesis is used to produce bioderived trans,trans-muconates as precursors to renewable terephthalates, important building blocks in the polymer industry.

Full text of DOI:10.1002/cssc.201701874

Accepted Article
Title: Bio-derived muconates via cross-metathesis and their conversion
to terephthalates
Authors: Erisa Saraci, Lan Wang, Klaus Theopold, and Raul Francisco
Lobo
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conversion (77 – 100%) and yield (70 − 98%) in all solvents
investigated, methanol and tetrahydrofuran being the best. Next,
the aromatization of 1,4-bis(carbomethoxy) cyclohexene to
dimethyl terephthalate over Pd/C catalyst resulted in up to 70%
yield in tetrahydrofuran and an air atmosphere. Due to the high
yield of the reaction of dimethyl muconate to 1,4-
bis(carbomethoxy) cyclohexene, no separation step is needed
before the aromatization. This is the first time that cross-
metathesis has been used to produce bio-derived trans,trans-
muconates as precursors to renewable terephthalates, important
building blocks in the polymer industry.
Bio-derived muconates via
cross-metathesis and their
conversion to terephthalates
Erisa Saraçi[a], [b], Lan Wang[a], [c], Klaus H.
Theopold[a], [c], Raul F. Lobo[a], [b]
Abstract: Polyethylene terephthalate that is 100% bio-derived is
in high demand in the market guided by the ever more exigent
sustainability regulations with the challenge remaining the
Introduction
production of renewable terephthalic acid. Renewable The production of industrial chemical intermediates from
terephthalic acid or its precursors can be obtained via Diels-Alder renewable resources is an alternative to petrochemicals,
cycloaddition and further dehydrogenation of biomass-derived often offering energy savings and contributing to sustainable
muconic acid. The cis,cis-isomer of the dicarboxylic acid is development.[1] Among these intermediates, renewable
[
2]
typically synthesized using fermentation with genetically modified polymer building blocks are especially attractive, as many
microorganisms, a process that requires complex separations to of them are oxygenates (as is biomass) and they are used in
obtain a high yield of the pure product. Furthermore, the cis very large quantities.[ Purified terephthalic acid (PTA), a
isomer has to be transformed into the trans,trans-form and has to building block of poly(ethylene terephthalate) (PET), is a very
be esterified before being suitable for the terephthalate synthesis. high-demand, commodity chemical. The industrial
To overcome these challenges we have investigated the manufacture of PTA is primarily based on the catalytic aerobic
synthesis of dialkyl muconates via cross-metathesis. The Ru- oxidation of petroleum-based p-xylene in acetic acid, over
catalyzed cross-coupling of sorbates with acrylates, which can be cobalt-, manganese-, and bromide-based catalysts, known as
bio-derived, proceeds selectively to yield up to 41% di-ester the AMOCO process.[4] There is strong interest to develop
muconates using very low catalyst amounts (0.5 – 3.0 mol.%) and sustainable processes for the production of 100% renewable
no solvent. In the optimized procedure, the muconate precipitates PET.[ The current bio-PET in the market is in fact only 30%
as a solid and is easily recovered from the reaction medium. GC- renewable—accounting for the mono ethylene glycol, which
MS and NMR analysis showed that this method delivers is already produced from biomass.[6] The other building block,
exclusively the trans,trans isomer of dimethyl muconate. The PTA, is fossil-fuel derived.[7] Bio-PTA production will allow for
Diels-Alder reaction of dimethyl muconate with ethylene was the production of 100% bio-based PET.
3]
5]
studied in various solvents to obtain the 1,4-bis(carbomethoxy)
cyclohexene. The cycloaddition proceeded in very high A number of routes have been investigated for the synthesis
of bio-based p-xylene: via pyrolysis of waste biomass (with
yields of up to 11%),[ using bio-ethylene (49% yield), from
isobutanol (18.7% yield)[10] and from 5-hydroxymethylfurfural
(HMF) (90% yield).[11] Most of these reaction paths have
insufficient selectivity to p-xylene and an additional oxidation
step is needed to produce the PTA.[ While the highest yield
to p-xylene from the aforementioned routes is from HMF,[13]
8]
[9]
[
a]
E. Saraçi, L. Wang, K. H. Theopold, R. F. Lobo
Catalysis Center for Energy Innovation
U.S. Department of Energy—Energy Frontier Research Center
University of Delaware
12]
221 Academy St., Newark, DE 19716 (USA)
E-mail: lobo@udel.edu
[
[
b]
c]
E. Saraçi, R. F. Lobo
Department of Chemical and Biomolecular Engineering
University of Delaware
the problematic separation and high production cost of
HMF[14] limit its use as a PTA precursor.[15]
150 Academy St., Newark, DE 19716 (USA)
L. Wang, K. H. Theopold
Department of Chemistry and Biochemistry
University of Delaware
Several biomass-based PTA synthesis routes that avoid p-
xylene as an intermediate have also been proposed.
Limonene, extracted from orange peels for example, can
afford PTA after only two steps: i) dehydrogenation to p-
102 Brown Laboratory, Newark, DE 19716 (USA)
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cymene and ii) oxidation to PTA.[16] However, the limited produce the cis,cis isomers of the muconic acid, which, in
production capacity of limonene, and its competitive uses as order to be transformed in to terephthalates, has to undergo
food and perfume additives restrict its use as PTA feedstock. two additional steps: i) the isomerization to the all trans
Diels-Alder cycloaddition of isoprene with acrylic acid leads to isomer and ii) esterification of the acid to increase solubility.[
23]
4-methyl-1-cyclohexene-1-carboxylic
acid
and
the It is then clear that an alternative route to muconic acid or its
subsequent oxidation of this cycloadduct forms terephthalic esters would be highly desirable, to facilitate its use as a PTA
acid in 78% yield.[
17]
The main drawbacks here are the precursor.
competitive demands for the high value-added starting
materials and the strongly corrosive homogeneous catalysts Olefin metathesis is one of the most powerful modern
used for the oxidation. Diels-Alder reaction with ethylene has methods for the formation of new carbon-carbon bonds.[24] Its
also been applied to biomass-derived chemicals, such as in mechanism, proposed in the 70s by Herisson and Chauvin,[
the reaction of 2,5-furandicarboxylic acid (FDCA), or its esters, involves the [2+2] cycloaddition of an alkene double bond to
with ethylene and subsequent dehydration, which gives a transition metal alkylidene to form a metallacyclobutane
PTA.[18] While this route would have only 4-5 steps from intermediate. Cleavage of this intermediate can then yield a
fructose to PTA, the reported yields are very low (0.14 % new alkene and alkylidene. Interaction with the d-orbitals on
according to one example disclosed in the patent[18b]). Other the metal catalyst lowers the activation energy enough so the
Diels-Alder reactions with ethylene for the production of bio- reaction can proceed rapidly at modest temperatures.[26]
PTA involve renewable sorbic acid[15b] and muconic acid.[19] Catalysts that can be used for cross-metathesis reactions
While the renewable sorbic acid route comprises fewer steps between olefins with functional groups are typically ruthenium
to para-substituted toluates, namely the cycloaddition with carbenes, owing to their functional group tolerance.[27] Cross-
ethylene and the consecutive aromatization, the yields in metathesis of unsaturated fatty acid derivatives with electron
each step are low, i.e., 13% and 30% respectively.[15b] The deficient substrates, such as acrylic acid or its equivalents,
cycloaddition of the muconic acid or its esters with ethylene has been studied in the last decades as a route to bio-sourced
gives cyclohex-2-ene-1,4-dicarboxylic acid, which, upon monomers used for the production of polyesters.[28] Cross-
catalytic dehydrogenation, can be transformed to PTA in high metathesis has, however, never been considered for the
yields (80-98%).[20] Although this method is very promising, synthesis of important PET precursors, such as muconic acid.
muconic acid can only be produced via fermentation of Previous work has shown that it is possible to synthesize
biomass glucose by genetically modified strains and in low muconates, although in relatively low yields (~30%) for high
yields (<30%).[21] Furthermore, the use of genetically catalyst amounts (5.0 mol.%), via the cross-metathesis route
engineered microorganisms, their sensitivity to muconic acid from unsaturated carboxylic acids.[29] Inspired by this
and the costly multi-step process of the product recovery from chemistry, we have investigated an alternative approach to
the synthesis broth,[20c, 21b, 22] detract from the process muconates via the cross-metathesis reaction of sorbates with
efficiency.The fermentation route affords only the cis,cis- acrylates (Scheme 1).
25]
isomer of the muconic acid, To date, other methods can only
Scheme 1. Synthesis of muconates via cross-metathesis of sorbates and acrylates and its byproducts.
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One of the main challenges with the cross-metathesis Catalysts screening. Several commercially available Ru-
reaction is the selectivity towards the cross-coupled product. catalysts were investigated for the reaction between ethyl-
As illustrated in Scheme 1, the main side products expected substituted sorbate and acrylate esters (Figure 1). One of the
from the metathesis reaction of sorbate and acrylate esters major drawbacks of ruthenium carbene catalysts in many
are the self-metathesis products, the resulting gaseous reactions is the lifetime and efficiency of these catalysts.[
compounds and compound D which is a product of secondary For the cross-metathesis reaction between ethyl-substituted
metathesis reactions between A and propene, or B and sorbate and acrylate esters, first (catalyst I) and second-
37]
butene.
generation (catalyst II) Hoveyda-Grubbs catalysts were
This route has the potential to produce a valuable product investigated. Catalyst I, containing a phosphine ligand, gave
from inexpensive materials.[30] Moreover, the starting the lowest conversion and selectivity towards the desired
materials, i.e., sorbates and acrylates, can be derived from product, diethyl muconate, when compared to all the catalysts
renewable carbon sources[31]. Plant-derived sorbic acid was tested. The second generation Hoveyda-Grubbs catalyst II,
first obtained from the extraction of the essential oil of containing an N-heterocyclic carbene (NHC) ligand,
nonedible mountain-ash berries (Sorbus aucuparia).[32] Since demonstrated a higher metathetic activity. The increased
this method gives limited quantities of the sorbic acid, other reactivity of NHC-based catalysts relative to phosphine-
bio-routes to sorbic acid have been proposed. Bio-sourced based catalysts in cross-metathesis is attributed to their
sorbic acid can be synthesized from bioethanol after its higher tolerance toward functionalized olefins.[38] In addition,
oxidation to acetaldehyde, trimerization to 2,4-hexadienal it has been shown that this catalyst (II) can be recycled via
[
30b]
[39]
(
sorbaldehyde), and, finally, oxidation to sorbic acid.
silica gel chromatography.
Two other variations of the
Hydrogenation of the renewable 4-hydroxy-6-methyl-2- second generation of Hoveyda-Grubbs catalyst II were also
pyrone (HMP) to 4-hydroxy-6-methyltetrahydro-2-pyrone (4- tested, namely catalysts III and IV, due to the fact that they
HMTHP) and its further dehydration by contacting it with a can be recovered from the reaction mixture either by water
solid acid catalyst also generates parasorbic acid (PSA).[
33]
extraction (catalyst III), or by filtration through a short pad
[40]
On the other hand, bio-acrylic acid can be prepared from the of silica gel (catalyst IV).[41] These potentially recyclable
glucose-derived 3-hydroxypropionic acid,[17, 34] or from the catalysts were selected in consideration of the high cost of
dehydration of biomass-derived methyl lactate.[35] Muconic these materials and to avoid waste.
acid or its esters are excellent precursors for other polymer
building blocks, including adipic acid.[22c, 36]
The goal of this research was to take advantage of the
versatile metathesis chemistry, combined with the availability
of renewable and inexpensive starting materials to produce a
sustainable and low cost precursor to PTA, i.e., muconate
esters. Using Ru-catalysts the cross-metathesis between
methyl sorbate and methyl acrylate affords the trans,trans
isomer of dimethyl muconate in yields up to 40% for low
catalyst amounts (only 3.0 mol.%). The subsequent Diels-
Alder cyclization of the muconate with ethylene proceeds very
selectively to yield up to 98% dimethyl cyclohex-2-ene-1,4-
dicarboxylate, which can then be readily transformed to
dimethyl terephthalate without prior purification via oxidative
dehydrogenation in tetrahydrofuran over a Pd/C catalyst. The
method reported here keeps the carboxyl groups of the
starting materials in the final PTA after three reactions, and
accordingly has a very high atom economy to the target
product.
I
II
III
IV
Figure 1. Ru-catalysts tested for the cross-metathesis reaction
Among the ruthenium catalysts investigated, the activity and
was highest for catalyst IV (Table 1). This could be due to its
higher reaction rates at low concentration, and its improved
stability.[41] As seen in Table 1, the increasing activity for the
catalysts (from I to IV) correlates well with the attained yield
of the cross-metathesis product, A. When using a catalyst
Results and Discussion
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with low metathetic-activity the Type II olefin involved in the be of great environmental concern and make up an important
reaction (the acrylate) has a lower probability of participating part of the process cost. Since catalyst IV was one of the most
in the cross-metathesis reaction and will act almost as a Type effective catalysts in our study (Table 1), it was used to
III olefin (no homodimerization activity). That is why cross- understand the solvent dependence on the cross-metathesis
metathesis probability, and, thus, selectivity to A, is higher for between ethyl sorbate and ethyl acrylate. Two commonly
catalyst with good activity when Type I and II olefins are used solvents in cross-metathesis reactions are
involved in the reaction. Similar findings for styrene and dichloromethane (DCM) and toluene.[43] DCM performs
stilbene cross-metathesis have been reported[24a]
.
slightly better than toluene (Table 2) although the differences
are small. In fact, more polar solvents[44] and those with
smaller molecular sizes[45] tend to give better results in the
cross-metathesis. However, the neat reaction using ethyl
acrylate as the solvent and as the reactant in 5-fold excess
provided higher conversion and selectivity towards the di-
ester muconate (Table 2).
Table 1. Cross-metathesis of ethyl sorbate with ethyl acrylate using
different ruthenium catalysts[a]
Entry
Catalyst
Conversion / %[b]
Yield
A
/ %[b]
Selectivity
34.6
/ %[b]
A
1
2
3
4
I
2.6
0.9
II
5.1
2.2
43.1
III
IV
13.2
16.5
6.3
47.7
Table 2. Solvent effect on the cross-metathesis of ethyl sorbate with ethyl
acrylate[a]
10.8
65.5
[a]Reaction conditions: catalyst 0.5 mol %, reflux, 5 equiv. excess ethyl
Entry
Solvent
No solvent 16.5
Conversion/ %[b] Yield
A
/ %[b]
SelectivityA`/ %[b]
2
acrylate, 323 K, 1 h, N atmosphere.
[b]Determined by GC.
1
2
3
10.8
5.3
65.5
57.6
50.8
DCM
9.2
6.3
Acrylic acid derivatives, which are α,β-unsaturated substrates,
are known to undergo homodimerization at a low rate, if at all,
and, thus, fall into the Type II category (slow
Toluene
3.2
[a]Reaction conditions: catalyst IV (0.5 mol %), reflux, 5 equiv. excess ethyl
acrylate, 323 K, 1 h, N
[b]Determined by GC.
2
atmosphere.
[
24a]
homodimerization) . This prediction was verified by the
resulting conversion of no more than 4.2% of ethyl acrylate
when it reacts alone in the presence of catalyst IV (0.10 It is established that the intermediate enoic carbenes,
mol.%) in methanol (3.00 mol/L) at 323 K over 2 hours. The [Ru]=CHCOOR, formed from the reaction of the catalyst with
resulting product from the GC analysis of the reaction mixture the acrylate,[44], are stabilized by excess acrylate owing to its
is dimethyl fumarate (C). Ethyl sorbate, on the other hand, lack of metathesis reactivity during the course of the
reacted much faster to reach a conversion of up to 40% at the reaction.[46] Not only does the absence of solvent provide a
same reaction conditions. The main products in this case more sustainable process, as it decreases waste, but the
were the self-coupled product, B (diethyl (2E,4E,6E)-octa- separation of the product from the reaction medium is also
2,4,6-trienedioate, 41% selectivity), which precipitates as a easier when fewer chemical species are present
deep red solid, and some D (ethyl crotonate, 38% selectivity).
The fast self-metathesis reaction of ethyl sorbate indicates Reactant substituent effects. Steric effects of the reactant
[
24a,
that it belongs to the type I olefins. Thus, having olefins of two molecules are an important factor in metathesis reactions
different types means that their reaction can result in selective
2
7b, 47]
and they were investigated by changing the size of the
cross-metathesis.[24a] In addition, note that ethyl crotonate (D) substituent of the acrylate ester reacting with the ethyl sorbate
is a very stable compound, which is a type III or even type IV (Table 3). The behavior of differently substituted acrylates as
olefin (no homodimerization or inert to cross-metathesis). substrates for the cross-metathesis with ethyl sorbate shows
When tested as a reactant in a control experiment, its reaction the same correlations that have been reported in previous
with ethyl sorbate gave almost the same products as the self- reports.[48] A larger carboxylic group substituent decreases
metathesis of ethyl sorbate at the same reaction conditions. the reaction rate of metathesis by making it more difficult for
the molecules to reach the Ru active site.[49] As seen in Table
This means that the formation of ethyl crotonate does not
favor the cross-metathesis mechanism. Similar results were 3, the smaller the substituent of the acrylate, the higher is the
obtained when methyl-substituted sorbate and acrylate esters conversion to the cross-metathesis product. Moreover, when
were used in control experiments.
the fumarate is used as a reactant (Table 3, entry 5) the
reactivity for cross-metathesis is further diminished, due to
One of the main goals in developing a green and sustainable the steric hindrance and the high stability of the di-ester.
process is to reduce the use of solvents,[42] since solvents can
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Table 3. Cross metathesis of ethyl sorbate and acrylates with different substituents [a]
Entry
Reactant 2
Conversion/ %[b]
Yield
14.3
10.8
6.6
A
/ %[b]
Selectivity
/ %[b]
A
1
2
3
4
5
21.2
16.5
11.2
9.5
67.5
65.5
58.9
4.6
48.4
5.0
2.1
42.0
[a]Reaction conditions: catalyst IV (0.5 mol %), reflux, 5 equiv. excess ethyl acrylate, 323 K, 1 h, N
atmosphere.
2
[b]Determined by GC.
Optimizing conditions for the synthesis of dimethyl better packing, precipitates quickly upon formation.
muconate. Consideration of the results described above Producing a solid, hardly soluble compound in this case is
guided the optimization of the dialkyl muconate synthesis. In advantageous because it drives the reaction forward. Further,
particular, methyl sorbates and acrylates were used as the separation of the product from the reaction mixture can be
reactants in the rest of the experiments as they showed the easily accomplished by filtration.
highest reaction rate. The cross-metathesis product, dimethyl
muconate, is an off-white solid which due to symmetry and
Table 4. Methyl sorbate conversion and dimethyl muconate yield in the cross-metathesis of methyl sorbate with methyl acrylate at different reaction
conditions[a]
.
Entry
Atm.
Air
T / K
293
293
293
323
323
323
323
323
n
cat./ mol.%
Reaction time/ h
Conversion / %[b]
Yield / %[b]
1.4
Selectivity/ % TON[c]
1
2
3
4
5
6
7
8
0.5
0.5
0.5
0.5
0.5
0.5
0.5
3.0
1
1
16
28
26
19
35
34
36
61
8.8
18.2
24.6
55.3
53.4
53.2
53.1
66.7
2.7
10
0.5
20
N
N
N
N
N
N
N
2
2
2
2
2
2
2
5.1
24
0.5
1
6.4
10.5
18.7
18.1
19.1
40.7
37
35
37
80
6
24
1
[a]Reaction conditions: catalyst IV, reflux, 10 equiv. excess methyl acrylate. [b]Determined by GC and solid product analysis.
[c]TON= moles of dimethyl muconate/ moles of catalyst
The cross-metathesis reaction conducted at room time course of the cross-metathesis of methyl sorbate with
temperature using methyl sorbate and methyl acrylate results methyl acrylate was investigated using series of
a
in low conversion (Table 4, entries 1 ‒ 3), compared to independent experiments (entries 4 ‒ 7). Our results show
reactions carried out at 323 K at otherwise identical conditions. that most of the conversion happens within the first hour of
Although the ruthenium catalyst IV, like other second the reaction, and there is little or no changes even after 24
generation Hoveyda-Grubbs catalysts, is more resistant hours of reaction (entry 7). Termination of product formation
towards deactivation by oxygen from the atmosphere,[50] it still before equilibrium has been reached is indicative of catalyst
deactivates under an air atmosphere for the typical reaction decomposition[45]. Entry 8 in Table 3 shows that although for
times, giving a low TON (see entry 1, Table 4). To determine practical reasons we kept the catalyst loading at very low
the stability of the catalyst under the reaction conditions, the levels (only 0.5 mol.%), the conversion and yield of the final
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product can be easily increased by increasing the amount of triene impurity.[23a, 52] 1H NMR spectra (400 MHz, CD
catalyst. The TON for this case is however low, due to catalyst trans,trans-dimethyl muconate: δ 7.35 (dd, 2H), 6.30 (d, 2H),
OD) of
3
13
deactivation over the course of reaction. Adding the Ru- 3.75 (s, 6H).
catalyst gradually over the course of the reaction can reduce trans,trans-dimethyl muconate: δ 51.6, 128.4, 141.6, 167.1.
the problem of deactivation,[29] but this was not part of this 1H NMR spectra (400 MHz, CD
OD) of dimethyl tamuate: δ
3
C NMR spectra (400 MHz, CD OD) of
3
investigation. Another reported way to improve cross- 7.38 (dd, 2H), 6.79 (dd, 2H), 6.13 (d, 2H), 3.76 (s, 6H).
metathesis efficiency by using low catalyst doses is to add
other compounds, e.g. p-cresol, iodites, that act as catalyst
stabilizers.[47, 51] Such compounds are usually toxic and their Elemental ICP-OES analysis showed that after filtration and
use would defy our efforts for a clean process with minimum purification of the dimethyl muconate product by
harmful waste. The turn over frequencies of the catalytic recrystallization in ethanol, its ruthenium content is below the
reactions are also shown for comparison in Table 4. The 50 ppm detection limit of ICP-OES. Most of the ruthenium
conditions that generate the highest TON in this case are the impurities remain in the liquid product mixture (reaction
conditions depicted in entry 5.
product filtrate) of the cross-metathesis reaction using 0.5
mol.% of catalyst IV, which after silica flash chromatography,
The purified dimethyl muconate obtained from the cross- affords a product mixture in which the residual Ru content is
metathesis of methyl sorbate and methyl acrylate was less than 100 ‒ 160 ppm (by ICP-OES analysis).
identified using GC-MS. Commercial trans,trans-dimethyl
muconate (Aldrich, CAS No.: 1733-37-5) was also analysed Dimethyl terephthalate synthesis from dimethyl
to confirm the MS spectra and the isomer type (E,E-); muconate. Frost et al.[20c] also described the formation of
methanol was used as a solvent. X-ray diffreaction patterns terephthalic acid by a Diels–Alder reaction between cis,cis-
of the as-synthesized and commercial dimethyl muconate muconic acid and ethylene and further dehydrogenation.[22b]
differed only in the presence of additional small diffraction Starting from a trans,trans-isomer of the muconate is much
peaks coming from the tamuate impurity in the synthesized better and it is crucial for cyclization with ethylene to prepare
dimethyl muconate product. 1H and 13C NMR spectral a terepthalic acid percursor[23b] (Scheme 2).
analysis of the product also confirmed the chemical structure
of the as-synthesized trans,trans-dimethyl muconate and the
Scheme 2. One-pot, two-step process of dimethyl terephthalate synthesis from the Diels-Alder reaction of dimethyl muconate with ethylene and the
subsequent aromatization of the Diels-Alder adduct in the presence of a Pd/C catalyst.
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The Diels–Alder reaction proceeds at high ethylene pressure
neat product mixture makes product separation and purification
unnecessary; it is possible to use the crude reaction mixture from
the first step (1 in scheme 2) as the starting material for the
dehydrogenation reaction with only the addition of Pd/C catalyst
(2 in scheme 2). The impurity present in the muconate product,
i.e., dimethyl tamuate, undergoes cycloaddition with ethylene in
low conversions (<15%), but it does not affect the stoichiometry
of the cyclohexene formation, due to the ethylene excess in the
reactor. This was verified in a control experiments with pure,
commercial dimethyl terephthalate, which was converted to the
same extend as the synthesized one at the same reaction
conditions.
(
here 2410 kPa), temperatures of around 423 K and without
catalyst.[
20b]
m-Xylene was initially used as a solvent,[20c] but the
solubility of the muconate was not sufficiently high in m-xylene.
Due to the low solubility of the dimethyl muconate in non-polar
solvents, polar solvents were tested, including ethyl acetate
(
EtOAc), methanol (MeOH), tetrahydrofuran (THF) and also
acetic acid (Table 5). The Diels-Adler reaction proceeds in high
conversion and yields in all solvents tested, especially in methanol
(
Table 5, entry 3 and 4), in which the conversion and selectivity
are the highest. The final product mixture from the Diels-Alder
reaction contains mainly the substituted cyclohexene product (B,
scheme 2), the unreacted dimethyl muconate and the tamuate
impurity of the muconate. The high yields of the product B and the
Table 5. Diels-Alder and consecutive aromatization conditions and results (conversion of the dimethyl muconate, A; yield of the cycloaduct, B; conversion of the
cycloaduct, B; yield of the dimethyl terephthalate, C) for the production of dimethyl terephthalate from dimethyl muconate
Diels-Alder
Conversion
Aromatization
Entry
Solvent
Atmosphere of 2
A
/ %
Yield
B
/ %
Conversion
B
/ %
C
Yield / %
1
2
3
4
5
6
7
9
m-Xylene
EtOAc
MeOH
MeOH
THF
N
N
N
2
2
2
77
88
100
98
96
98
95
85
76
76
98
96
75
77
74
70
-
-
-
-
93
62
73
97
54
61
33
55
49
68
32
44
Air
N
2
THF
Air
THF
O
2
Acetic Acid
Air
Diels-Alder reaction: 0.03 M dimethyl muconate in a solvent, 2400 kPa ethylene, 423 K, 24 h.
Aromatization reaction: 15 ml of the product mixture from the Diels-Alder reaction, 0.5 g of 10wt.% Pd/C catalyst, 3450 kPa N
2 2
/Air/O .
An optimal solvent for the production of terepthalates from
muconates was identified to carry out both reaction steps (1 and
(only 32% yield of C). In the absence of an oxidant and in inert
atmosphere (N , entry 5 Table 5), the aromatization of B to C
2
2
in Scheme 2) in a one-pot, same-solvent fashion. An
appropriate solvent for both steps would make the process
suitable for continuous flow reactor plant. While the
proceeds up to 49% yield. These results show that relatively low
partial pressures of oxygen promote the oxidative
dehydrogenation reactions over Pd catalysts at moderated
temperatures.[55] High oxygen pressure in the reactor, consumes
the solvent in side reactions and drives the disproportionation of
the products towards the cyclohexane dicarboxylate.[56]
a
cycloaddition of the muconate with ethylene proceeds in high
yields of B, its conversion to dimethyl terephthalate is highly
dependent on the solvent and the atmosphere in the reactor
during the dehydrogenation reaction. The main side product of the
aromatization step is the fully hydrogenated cyclohexane
dicarboxylate.[ Methanol turned out to be an unsuitable solvent
for the dehydrogenation step as it undergoes partial
decomposition over the palladium catalyst independently of the
atmosphere of the reaction (entries 3 and 4 in Table 5)[54]. Acetic
acid is a good solvent for the dimethyl muconate, but its high
reactivity with the catalyst and the metal walls of the reactor
makes it a poor candidate for our sequential transformations. THF,
on the other hand, gives a good yield in the first cycloaddition step
and in the oxidative dehydrogenation step it gives yields up to
53]
Conclusions
This report showed that dialkyl muconates can be successfully
synthesized via cross-metathesis. Low amounts (up to 3.0 mol.%)
of the second generation, NHC-based Hoveyda-Grubbs catalyst
can be used efficiently (up to 41% yield) for this synthesis, due to
their high metathetic activity and stability. The starting reagents,
sorbate and acrylate esters, are inexpensive and can be derived
from biomass waste. Moreover, no solvent is used in the
muconates synthesis, adding more sustainability value to this
process. NMR and GC-MS analysis established the formation of
the trans,trans-isomer of dimethyl muconate. The trans form of
68% when air (as source of oxidant) is present in the reactor
headspace. When the reactor is filled with pure oxygen (1380
kPa) as oxidant, THF is consumed in side reactions and the
efficiency of the dehydrogenation reaction decreases significantly
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ChemSusChem
10.1002/cssc.201701874
FULL PAPER
muconates is important, as it makes them readily transformable
precursors to important polymer building blocks, such as
terephthalic or adipic acid, making this synthesis route superior to
other bio-synthesis methods, which can only produce the cis
isomer of muconic acid. The as-synthesized trans,trans-dimethyl
muconate is further transformed into dimethyl terephthalate by
undergoing a Diels-Alder cyclization with ethylene to give 1,4-
Bis(carbomethoxy) cyclohexene (up to 98% yield), which is then
dehydrogenated in the same pot and solvent into dimethyl
terephthalate over a Pd/C catalyst (68% yield). This method for
obtaining bio-derived dimethyl muconate via cross-metathesis as
a precursor to renewable dimethyl terephthalate, can also be
applied to produce other bio-derived polymer building blocks, like
terephthalic acid, its other esters, trimellitic acid, adipic acid, etc.
Although the yield of the methyl muconate remains low for
commercial interest, our results point towards the focus of future
research for improving the synthesis of bio-sourced
terephthalates.
The selectivity of the products is defined as the ratio of the desired
product, A, to the rest of the detectable products by GC-MS.
Gaseous byproducts are not considered in this analysis.
When a solid muconate product was formed, it was separated
from the reaction mixture via filtration and thoroughly washed with
ethanol. The liquid product mixture of the reaction was purified
from ruthenium residues by flash chromatography using Merck
silica gel 60 (230 ‒ 400 mesh)[ . The solid dimethyl muconate
contained dimethyl tamuate (dimethyl 2,4,6-octatrienedioate,
CAS No. 13160-88-8)[52] as impurity. The ratio of the muconate to
41]
1
tamuate determined from H-NMR was 7:1.
The Diels-Alder and dehydrogenation-aromatization reactions
were conducted in a 5512-series Parr reactor. For the Diels-Alder
reaction, the Parr reactor internal Teflon liner was loaded with the
dimethyl muconate (0.1 g) in a solvent (0.03 M). After assembly
of the Parr reactor, its contents were degassed three times with
2
N (2760 to 3450 kPa). The internal pressure was then allowed to
decrease to a relative pressure 0 kPa, at which point ethylene (Air
Liquide, 99.6%) was introduced up to the desired pressure (2400
kPa). Following the detachment of the gas feed lines, the contents
of the Parr reactor were heated to 423 K. After the desired amount
of time, the reaction was quenched by cooling in an ice bath to
room temperature, and it was degassed by opening the exhaust
valve. The contents of the reactor were then analyzed by GC-MS.
For the dehydrogenation reactions, the product mixture from the
Diels-Alder cyclization reaction described above, served as a
starting solution for the aromatization reaction to produce
dimethyl terephthalate. 0.5 g of 10wt.% Pd/C catalyst were added
to 15 ml of the reaction mixture in the Parr reactor. Independently
of the gas atmosphere present in the reactor, its content was
Experimental Section
All of the reagents were purchased from SigmaAldrich and were
used as received, without further purification. The metathesis
catalysts (Figure 1) were purchased from Aldrich
(
3
Hoveyda−Grubbs I, CAS No. 203714-71-0; Hoveyda−Grubbs II,
01224-40-8) and Strem Chemicals (GreenCat, 1448663-06-6;
StickyCat Cl, CAS No. 1452227-72-3).
ICP-OES analysis for evaluating the Ru content (method: GLI
Procedure ME-70) were done by the Galbraith Laboratories, Inc.
(
Knoxville,TN). XRD patterns were collected using a Bruker D8
2
always pressurized with N to 3450 kPa, to maintain overpressure
diffractometer with CuKα radiation source. The pattern was
collected for 0.5 s at each increment of 0.02⁰ between 5 and 50⁰.
NMR spectra were recorded on a Bruker DRX-400 spectrometer
for all experiments. After the reaction was complete, the catalyst
was removed by filtration and the reaction mixture was analysed
by GC-MS. The conversions and yields for the Diels-Alder and
dehydrogenation reactions were calculated using equations 1 and
and were referenced to the residual protons of the solvent (CD
2 2
Cl ,
5
.32 ppm; CD OD, 4.87 ppm). The spectra were analyzed with
3
2
above.
the MestReNova software. All liquid products were analyzed with
a GC-MS (Agilent 7890B GC system and 5977A MSD) equipped
with an FID. A DB-5 column (30.0 m x 250 µm x 0.25 µm) was
used with the following temperature program for all analysis: hold Acknowledgements
at 313K for 4 min, 10 K min-1 ramp to 523 K, and a final hold for 4
min. Retention times and calibrations of reactants and products
were determined from calibration solutions of the commercial
compounds.
This report is based upon work supported as part of the Catalysis
Center for Energy Innovation, an Energy Frontier Research
Center funded by the U.S. Department of Energy, Office of
Science, Office of Basic Energy Sciences under Award Number
DE-SC0001004.
The cross-metathesis reaction was conducted in a 25 ml round
bottom flask connected to a condenser and a Schlenk line to
assure the absence of moisture and an inert atmosphere
Keywords: terephthalate • muconate • metathesis • Diels-Alder
(
nitrogen). The acrylate and sorbate esters were mixed in a molar
•
bio-derived chemical
ratio of 5 ‒ 10, with excess of acrylate. The ruthenium catalyst
was added in a predefined amount (0.1 ‒ 3.0 molar ratio of the
catalyst with respect to the sorbate) to the reaction mixture. The
reaction mixtures were analyzed using GC-MS. Conversion and
yield of the reaction were calculated on the sorbate basis as
follows:
[
1]
a) A. Corma, S. Iborra, A. Velty, Chem. Rev. 2007, 107, 2411-2502; b)
H. Roper, Starch-Starke 2002, 54, 89-99; c) A. L. Marshall, P. J.
Alaimo, Chem-Eur. J. 2010, 16, 4970-4980; d) S. Caratzoulas, M. E.
Davis, R. J. Gorte, R. Gounder, R. F. Lobo, V. Nikolakis, S. I. Sandler,
M. A. Snyder, M. Tsapatsis, D. G. Vlachos, J. Phys. Chem. C. 2014,
118, 22815-22833.
[
[
2]
3]
a) K. Muffler, R. Ulber, Chem. Eng. Technol. 2008, 31, 638-646; b) J. F.
Pang, M. Y. Zheng, R. Y. Sun, A. Q. Wang, X. D. Wang, T. Zhang,
Green Chem. 2016, 18, 342-359; c) Y. Q. Zhu, C. Romain, C. K.
Williams, Nature 2016, 540, 354-362.
A. Llevot, P. K. Dannecker, M. von Czapiewski, L. C. Over, Z. Soyler,
M. A. R. Meier, Chem-Eur J. 2016, 22, 11509-11520.
푀ꢀ푙ꢁꢂ ꢀ푓 ꢃꢁ푎푐푡푎ꢄ푡 푐ꢀꢄꢅꢁꢃ푡ꢁ푑
퐶표푛푣푒푟푠푖표푛 (푋) =
푌푖푒ꢆꢇ (푌) =
1
2
푀ꢀ푙ꢁꢂ ꢀ푓 ꢃꢁ푎푐푡푎ꢄ푡 푓ꢁ푑
푀ꢀ푙ꢁꢂ ꢀ푓 푑ꢁꢂꢈꢃꢁ푑 푝ꢃꢀ푑푢푐푡
푀ꢀ푙ꢁꢂ ꢀ푓 ꢃꢁ푎푐푡푎ꢄ푡 푓ꢁ푑
This article is protected by copyright. All rights reserved.

ChemSusChem
10.1002/cssc.201701874
FULL PAPER
[
4]
a) X. B. Zuo, B. Subramaniam, D. H. Busch, Ind. Eng. Chem. Res.
[32] a) L. J. Haynes, E. R. H. Jones, J. Chem. Soc. 1946, 954-957; b) U.
Brunner, J. Biol. Educ. 1985, 19, 41-47.
2008, 47, 546-552; b) R. A. F. Tomas, J. C. M. Bordado, J. F. P.
Gomes, Chem. Rev. 2013, 113, 7421-7469.
[33] J. A. Dumesic, M. Chia, Vol. US8404890B2, Wisconsin Alumni
Research Foundation, U.S. Patent US8404890B2, 2013.
[34] V. Kumar, S. Ashok, S. Park, Biotechnol. Adv. 2013, 31, 945-961.
[35] a) H. T. Alexander, Chem. Eng. News 2013, 91, 18-19; b) B. M.
Murphy, M. P. Letterio, B. J. Xu, ACS Catal. 2016, 6, 5117-5131.
[36] N. A. Rorrer, J. R. Dorgan, D. R. Vardon, C. R. Martinez, Y. Yang, G. T.
Beckham, Acs Sustain. Chem. Eng. 2016, 4, 6867-6876.
[37] S. H. Hong, A. G. Wenzel, T. T. Salguero, M. W. Day, R. H. Grubbs, J.
Am. Chem. Soc. 2007, 129, 7961-7968.
[
5]
a) J. C. Serrano-Ruiz, R. Luque, A. Sepulveda-Escribano, Chem. Soc.
Rev. 2011, 40, 5266-5281; b) A. M. Balu, B. Baruwati, E. Serrano, J.
Cot, J. Garcia-Martinez, R. S. Varma, R. Luque, Green. Chem. 2011,
13, 2750-2758; c) T. Werpy, G. Petersen, in Top Value Added
Chemicals from Biomass, Vol. 1, US Department of Energy, 2004.
D. I. Collias, A. M. Harris, V. Nagpal, I. W. Cottrell, M. W. Schultheis,
Ind. Biotechn. 2014, 10, 91-105.
[
[
6]
7]
a) M. M. Bomgardner, in Chemical and Engineering News, Vol. 92,
2
014, pp. 10-14; b) B. Xiao, M. Y. Zheng, J. F. Pang, Y. Jiang, H.
[38] T. Ritter, A. Hejl, A. G. Wenzel, T. W. Funk, R. H. Grubbs,
Organometallics 2006, 25, 5740-5745.
[39] S. B. Garber, J. S. Kingsbury, B. L. Gray, A. H. Hoveyda, J. Am. Chem.
Soc. 2000, 122, 8168-8179.
Wang, R. Y. Sun, A. Q. Wang, X. D. Wang, T. Zhang, Ind. Eng. Chem.
Res. 2015, 54, 5862-5869.
a) K. Jacobson, K. C. Maheria, A. K. Dalai, Renew. Sust. Energ. Rev.
[
8]
9]
2
013, 23, 91-106; b) T. R. Carlson, Y. T. Cheng, J. Jae, G. W. Huber,
[40] K. Skowerski, C. Wierzbicka, G. Szczepaniak, L. Gulajski, M. Bieniek,
K. Grela, Green Chem. 2012, 14, 3264-3268.
Energ. Environ. Sci. 2011, 4, 145-161.
[
a) P. C. A. Bruijnincx, B. M. Weckhuysen, Angew. Chem. Int. Edit.
[41] K. Skowerski, P. Kasprzycki, M. Bieniek, T. K. Olszewski, Tetrahedron
2013, 69, 7408-7415.
2013, 52, 11980-11987; b) J. B. Binder, R. T. Raines, J. Am. Chem.
Soc. 2009, 131, 1979-1985.
10] J. Sun, C. Liu, Y. Wang, C. Smith, K. Martin, P. Venkitasubramanian,
Vol. US 20140121430A1, 2014.
11] a) B. Saha, M. M. Abu-Omar, Chemsuschem 2015, 8, 1133-1142; b) S.
Dutta, S. De, B. Saha, Chempluschem 2012, 77, 259-272.
12] F. Wang, Z. H. Tong, Chemistryselect 2016, 1, 5538-5541.
13] a) C. L. Williams, C. C. Chang, P. Do, N. Nikbin, S. Caratzoulas, D. G.
Vlachos, R. F. Lobo, W. Fan, P. J. Dauenhauer, ACS Catal. 2012, 2,
[42] T. Welton, in Royal Society A-Mathematical Physical and Engineering
Sciences, Vol. 471, 2015, p. 20150502.
[
[
[43] a) M. Zirngast, E. Pump, A. Leitgeb, J. H. Albering, C. Slugovc, Chem.
Commun. 2011, 47, 2261-2263; b) S. Guidone, E. Blondiaux, C.
Samojlowicz, L. Gulajski, M. Kedziorek, M. Malinska, A. Pazio, K.
Wozniak, K. Grela, A. Doppiu, C. S. J. Cazin, Adv. Synth. Catal. 2012,
354, 2734-2742.
[
[
[44] T. L. Choi, C. W. Lee, A. K. Chatterjee, R. H. Grubbs, J. Am. Chem.
Soc. 2001, 123, 10417-10418.
935-939; b) N. Nikbin, P. T. Do, S. Caratzoulas, R. F. Lobo, P. J.
Dauenhauer, D. G. Vlachos, J. Catal. 2013, 297, 35-43.
14] Z. J. Lin, M. Ierapetritou, V. Nikolakis, Aiche J. 2013, 59, 2079-2087.
15] a) C. Detoni, C. H. Gierlich, M. Rose, R. Palkovits, Acs. Sustain. Chem.
Eng. 2014, 2, 2407-2415; b) S. Berard, C. Vallee, D. Delcroix, Ind. Eng.
Chem. Res. 2015, 54, 7164-7168; c) X. Q. Yu, Y. Q. Wen, T. Yuan, G.
Li, Chemistryselect 2017, 2, 1237-1240.
[45] D. Schweitzer, K. D. Snell, Org. Process Res. Dev. 2015, 19, 715-720.
[46] M. Abbas, C. Slugovc, Tetrahedron Lett. 2011, 52, 2560-2562.
[47] K. Voigtritter, S. Ghorai, B. H. Lipshutz, J. Org. Chem. 2011, 76, 4697-
4702.
[
[
[48] J. S. Cannon, R. H. Grubbs, Angew. Chem. Int. Edit. 2013, 52, 9001-
9004.
[
[
16] C. Okkerse, H. van Bekkum, Green Chem. 1999, 1, 107-114.
17] K. K. Miller, P. Zhang, Y. Nishizawa-Brennen, J. W. Frost, ACS Sustain.
Chem. Eng. 2014, 2, 2053-2056.
[49] N. Vinokurov, A. Michrowska, A. Szmigielska, Z. Drzazga, G. Wojciuk,
O. M. Demchuk, K. Grela, K. M. Pietrusiewicz, H. Butenschon, Adv.
Synth. Catal. 2006, 348, 931-938.
[
18] a) J. J. Pacheco, J. A. Labinger, A. L. Sessions, M. E. Davis, ACS
Catal. 2015, 5, 5904-5913; b) W. H. Gong, Vol. US 8,299,278 B2, US,
[50] T. Nicola, M. Brenner, K. Donsbach, P. Kreye, Org. Process Res. Dev.
2005, 9, 513-515.
2
012.
[51] a) G. S. Forman, R. P. Tooze, J. Organomet. Chem. 2005, 690, 5863-
5866; b) M. Abbas, A. Leitgeb, C. Slugovc, Synlett. 2013, 24, 1193-
1196.
[
[
19] J. W. Frost, Draths Corporation, U.S. Patent US2010314243-A1, 2010.
20] a) J. W. Frost, A. Miermont, D. Schweitzer, V. Bui, E. Paschke, D. A.
Wicks, Vol. US 8,415,496 B2, Amyris Inc., 2013; b) R. Lu, F. Lu, J. Z.
Chen, W. Q. Yu, Q. Q. Huang, J. J. Zhang, J. Xu, Angew. Chem. Int.
Edit. 2016, 55, 249-253; c) J. W. Frost, A. Miermont, D. Schweitzer, V.
Bui, D. A. Wicks, Vol. US 8,367,858 B2, Amyris, Inc.,, 2013.
[52] F. A. Cotton, J. P. Donahue, C. A. Murillo, J. Am. Chem. Soc. 2003,
125, 5436-5450.
[53] T. Dai, C. Z. Li, B. Zhang, H. W. Guo, X. L. Pan, L. Li, A. Q. Wang, T.
Zhang, Chemsuschem 2016, 9, 3434-3440.
[
[
21] a) J. W. Frost, K. M. Draths, Vol. US 5,616,496, Purdue Research
Foundation, 1997; b) N. Z. Xie, H. Liang, R. B. Huang, P. Xu,
Biotechnol. Adv. 2014, 32, 615-622.
[54] M. Baumer, J. Libuda, K. M. Neyman, N. Rosch, G. Rupprechter, H. J.
Freund, Phys. Chem. Chem. Phys. 2007, 9, 3541-3558.
[55] N. F. Dummer, S. Bawaked, J. Hayward, R. Jenkins, G. J. Hutchings,
Catal. Today 2010, 154, 2-6.
22] a) N. J. H. Averesch, J. O. Kromer, Metabol. Eng. Comm. 2014, 1, 19-
28; b) C. Weber, C. Brueckner, S. Weinreb, C. Lehr, C. Essl, E. Boles,
[56] A. V. Iosub, S. S. Stahl, J. Am. Chem. Soc. 2015, 137, 3454-3457.
Appl. Environ. Microb. 2012, 78, 8421-8430; c) D. R. Vardon, N. A.
Rorrer, D. Salvachua, A. E. Settle, C. W. Johnson, M. J. Menart, N. S.
Cleveland, P. N. Ciesielski, K. X. Steirer, J. R. Dorgan, G. T. Beckham,
Green Chem. 2016, 18, 3397-3413.
[
[
23] a) J. M. Carraher, T. Pfennig, R. G. Rao, B. H. Shanks, J. P.
Tessonnier, Green Chem. 2017, 19, 3042-3050; b) J. W. Frost, A.
Miermont, D. Schweitzer, V. Bui, Vol. US8426639B2, U. S. Patent
US8426639B2, 2013.
24] a) A. K. Chatterjee, T. L. Choi, D. P. Sanders, R. H. Grubbs, J. Am.
Chem. Soc. 2003, 125, 11360-11370; b) A. H. Hoveyda, A. R.
Zhugralin, Nature 2007, 450, 243-251.
[
[
[
25] P. Jean-Louis Hérisson, Y. Chauvin, Die Makromolek. Chem. 1971,
1
41, 161-176.
26] G. C. Vougioukalakis, R. H. Grubbs, Chem. Rev. 2010, 110, 1746-
787.
1
27] a) A. Furstner, Angew. Chem. Int. Edit. 2000, 39, 3012-3043; b) R. H.
Grubbs, Tetrahedron 2004, 60, 7117-7140; c) J. Prunet, Eur. J. Org.
Chem. 2011, 3634-3647.
[
28] a) A. Rybak, M. A. R. Meier, Green Chem. 2007, 9, 1356-1361; b) A.
Behr, J. P. Gomes, Z. Bayrak, Eur. J. Lipid Sci. Tech. 2011, 113, 189-
196; c) P. Vignon, T. Vancompernolle, J. L. Couturier, J. L. Dubois, A.
Mortreux, R. M. Gauvin, Chemsuschem 2015, 8, 1143-1146.
29] L. Ferrie, D. Amans, S. Reymond, V. Bellosta, P. Capdevielle, J. Cossy,
J. Organomet. Chem. 2006, 691, 5456-5465.
30] a) A. J. J. Straathof, S. Sie, T. T. Franco, L. A. M. van der Wielen, Appl.
Microb. Biotechn. 2005, 67, 727-734; b) C. L. Dorko, G. T. Ford, Jr., M.
S. Baggett, A. R. Behling, H. E. Carman, in Kirk-Othmer Encyclopedia
of Chemical Technology, Vol. 5, 5 ed., Wiley−Interscience, Hoboken,
NJ, 2000.
[
[
[
31] a) C. Gao, C. Ma, P. Xu, Biotechn. Adv. 2011, 29, 930-939; b) J. T.
Claypool, R. D. Raj, in Agricultural and Biosystems Engineering
Conference Proceedings, Vol. 48, 2012.
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Entry
for the Table of Contents
FULL PAPER
Author(s), Corresponding Author(s)*
Page No. – Page No.
Title
Cross-road to green terephthalate rings metathesized: Cross-
metathesis was used for the first time to produce renewable
terephthalate PET precursors. Moderate amounts of Ru-catalyst
and no solvents gave pure trans isomer of the muconates, which
can then be readily converted to terephthalates by combining
consecutive Diels-Alder and aromatization reactions in the same
solvent with very high efficiency.
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