Direct esterification of succinic acid with phenol using zeolite beta catalyst

Article abstract of DOI:10.1016/j.catcom.2019.01.006

Direct esterification of succinic acid with phenol in the presence of zeolite catalysts was explored. H⁺-zeolite β (SiO₂/Al₂O₃ = 150) has emerged as the most effective solid acid catalyst, affording 96% yield of

Full text of DOI:10.1016/j.catcom.2019.01.006

Accepted Manuscript
Direct esterification of succinic acid with phenol using zeolite
beta catalyst
Son Dinh Le, Shun Nishimura, Kohki Ebitani
PII:
S1566-7367(19)30006-8
DOI:
Reference:
https://doi.org/10.1016/j.catcom.2019.01.006
CATCOM 5590
To appear in:
Catalysis Communications
Received date:
Revised date:
Accepted date:
12 November 2018
2 January 2019
7 January 2019
Please cite this article as: Son Dinh Le, Shun Nishimura, Kohki Ebitani , Direct
esterification of succinic acid with phenol using zeolite beta catalyst. Catcom (2018),
https://doi.org/10.1016/j.catcom.2019.01.006
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ACCEPTED MANUSCRIPT
Direct Esterification of Succinic Acid with Phenol using
Zeolite Beta Catalyst
Son Dinh Le, Shun Nishimura* s_nishim@jaist.ac.jp, Kohki Ebitani*
ebitani@jaist.ac.jp
Graduate School of Advanced Science and Technology, Japan Advanced Institute of
Science and Technology (JAIST), 1-1 Asahidai, Nomi, Ishikawa 923-1292, Japan
*Corresponding authors. ,
Abstract
Direct esterification of succinic acid with phenol in the presence of zeolite catalysts
was explored. H+-zeolite β (SiO2/Al2O3 = 150) has emerged as the most effective solid
acid catalyst, affording 96% yield of diphenyl succinate. The catalyst could be
recycled upon 5 consecutive runs without appreciable decreases in activity.
Additionally, the catalyst was successfully applied to the esterification of several
dicarboxylic acids with phenol producing good and moderate yields of the desired
products. The present method not only offers essential features of the heterogeneous
system but also brings simplicity in operation, which make it more economical and
environmentally-friendly.
Keywords: Esterification, Succinic acid, Phenol, Zeolite beta
1. Introduction

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It is indisputable that industries rely heavily on crude oil and its products
which are rapidly diminishing over centuries of exploitation. Besides the massive
increase in demand, large fluctuations in oil price subsequently cause several adverse
effects on the economy. Moreover, the consumption of fossil fuels also increases
significantly greenhouse gas emission, contributing to global warming and climate
change. To cope with these problems, it is imperative to implement changes from
fossil-based society to a more environmentally sustainable society by employing
biomass which is a promising renewable alternative.[1–4] Among various top value-
added chemicals reported by the U.S. Department of Energy in 2004, succinic acid
was identified as one of the most important bio-based chemicals which is able to
undergo a variety of reactions to useful products.[5–8] Despite the fact that numerous
publications in hydrogenation[9–12], there is limited information regarding
esterification of succinic acid with alcohols, and especially with phenol toward
diphenyl succinate, which has motivated the authors to conduct the present research.
Diphenyl dicarboxylates are important intermediates which are typically used
as a starting material in the preparation of para-quinone methides which appear in a
variety of pharmaceuticals, medicinal and biological processes.[13] Furthermore, they
can be employed as a reactive dienophile for effecting Diels-Alder reaction with
quinodimethanes[14], and a useful plasticizer for the synthesis of polyvinyl chloride,
copolymers various cellulose esters and synthetic rubbers.[15] In particular, diphenyl
succinate had been reported as an effectively bifunctional electrophile in the
production of Spiro-lactones[16] which may be useful for medical indications.
Direct esterification with phenol is no mean task and it has been a challenge
for many years, especially for the reaction with dicarboxylic acids.[17,18] The reason
behind is that the lone electron pairs on the oxygen atom of phenol are delocalized on

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the benzene ring, which makes phenol less nucleophilic than substituted phenol
compounds or alkanols.[19] Conventionally, 62-67% of diphenyl succinate which was
synthesized via direct esterification of succinic acid with phenol was reported in 1963
by Daub and Johnson.[20] However, in this process, stoichiometric amounts of toxic
reagents such as phosphorous oxychloride and benzene were required. In 1971,
Lowrance reported the direct esterification of phenol with several carboxylic acids
using a combination of boric and sulfuric acids.[21] The advantage of this process is
that only catalytic amount of boric acid or a combination with sulfuric acid was
employed. Nevertheless, similar to the former process, this suffered from the
difficulty of separation, the inability of reusability which are typical encountered in
homogeneous catalyst systems.
Recently, with the extensive development of the heterogeneous system, solid
acids were studied for esterification of carboxylic acids with phenol. For instance,
Kaneda et al. explored titanium-montmorillonite (Ti4+-mont) as an efficiently reusable
solid acid catalyst for the esterification of carboxylic acids with alcohols and
phenol.[22] Particularly, 92% phenyl hexanoate was afforded by the reaction between
hexanoic acid and phenol over Ti4+-mont catalyst in an o-xylene solvent. Prakash et
al. reported metal-exchanged montmorillonites as potential solid acid catalysts for the
esterification of dicarboxylic acids with various alcohols to afford high yields of many
esters.[19] However, when it comes to the reaction with phenol, only modest yield,
25%, of diphenyl succinate was obtained.
In this paper, diphenyl succinate was synthesized via direct esterification of
succinic acid with phenol over various types of solid acid catalysts. The highest yield
up to present of the desired product was achieved using H+-zeolite β with SiO2/Al2O3
(Si/Al) = 150 in toluene solvent under optimized reaction conditions. (Scheme 1). The

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influence of the catalyst characteristics, i.e., Si/Al ratio, on the catalytic activity was
also investigated. Thereafter, the efficiency of the ideal protocol was tested for the
reaction with other dicarboxylic acids including malonic acid, glutaric acid, and
adipic acid.
2. Experimental
2.1. Materials
Succinic acid, citric acid, zirconium dioxide, zirconium chloride oxide
octahydrate, sodium chloride, sodium hydroxide, toluene, heptane, and acetonitrile
were supplied by Kanto Chemical Co., Inc. H+-zeolite β (JRC-HB150 and JRC-Z-
HB25) and H+-ZSM-5 (JRC-Z5-90H) were obtained from the Catalysis Society of
Japan. H+-zeolites β (HSZ-941HOA, HSZ-960HOA, HSZ-980HOA, and HSZ-
990HOA), H+-zeolite Y (HSZ-385HUA), and H+-mordenite (HSZ-690HOA) were
purchased from Tosoh Corporation. Amberlyst-35, Amberlyst-45, Amberlyst-46, and
acetonitrile-d3 were provided by Organo Co. Glutaric acid and Amberlyst-15 were
from Sigma Aldrich; whereas Na+-montmorillonite (Kunipia F) was from Kunimine
Industry Co. Ltd. Malonic acid, adipic acid, sulfated zirconia, 1,4-dioxane, ethyl
acetate, cyclohexane, hexane and dodecane were imported from Wako Pure Chemical
Ind. Ltd. Phenol and maleic acid were brought from Tokyo Chemical Industry Co.
Ltd. ). Zeolites were calcined at 500 °C for 5 h before use, while other chemicals were
used without any purification or treatment.
2.2. Typical reaction procedure

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The esterification of succinic acid with phenol was carried out in a 20-mL
round-bottom flask fitted with a reflux condenser. First, the flask was charged with
succinic acid (1 mmol), phenol (3 mmol), catalyst (0.1 g), and solvent (5 mL).
Subsequently, the reaction mixture was refluxed for 6 h at 400 rpm.
2.2. Analysis methods
To identify the product, proton nuclear magnetic resonance (1H-NMR) was
employed (Bruker Avance III, 400 MHz). Acetonitrile-d3 was used to dissolve the
product, while maleic acid (purity = 99%) was added as an internal standard. Then,
the synthesized products with high purity (99%) were used to draw a calibration curve
with an internal standard (dodecane) for gas chromatography (Shimadzu GC-2014).
The temperature program was from 40 °C (3 min) to 100 °C (5 min) at a rate of 20 °C
min-1. Then the temperature was increased to 200 °C (0 min) and 270 °C (3 min) at a
rate of 10 and 20 °C min-1, respectively. The injector and detector temperatures were
270 °C. A non-polar DB-1 column (Agilent) was used for GC analysis. Calibration
curves were shown in Figures S1 and S2 (See Supplementary data).
The yield of the product was calculated based on the mole of succinic acid
following the formulas:
Mole of diphenyl succinate ×100
(2.1)
( )
Yield % =Mole of initial succinic acid
Whereas the conversion of phenol was calculated as follows:
Conv. % =Mole of consumed phenol ×100
(2.2)
( )
Mole of initial phenol
Selectivity of the product was calculated based on the consumed amount of
phenol, which is described below:

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Sel. % =2 × mole of diphenyl succinate ×100
(2.3)
( )
Mole of consumed phenol
3. Results and Discussion
A wide diversity of solid acid catalysts was investigated for the synthesis of
diphenyl succinate. The results are shown in Table 1.
Preliminary experiments with three types of as-prepared Mn+-montmorillonite
(mont) catalysts were carried out. The preparation of Mn+-mont catalysts are described
in the Scheme S1. In this series of experiments, Al3+-mont which gave the highest
yield of the product, 10% (entry 1), while lower yields of 7% and 4% were seen in the
case of Zr4+-mont and Cu2+-mont, respectively (entries 2 and 3). The highly polar
cation presented between the layers of Al3+-mont resulted in the increase in the
interlayer acidity may be distributed to the better yield of diphenyl succinate among
other clays.[23]
Next, several kinds of sulfonated Amberlyst resin catalysts[24] were also
investigated. Of which, surface-sulfonated Amberlyst-46 with the lowest acid amount
of 0.43 mmol g-1[25] brought the highest yield of the product, 42% (entry 4), while the
similar results, around 30%, were obtained in the case of Amberlyst-15 and
Amberlyst-35 (entries 5 and 6). The figure for Amberlyst-45 is lesser which was just
24% (entry 7). The results suggested that highly acid Amberlysts such as Amberlyst-
15, Amberlyst-35, and Amberlyst 45 which possess acid amounts of 4.70, 5.00, 2.95
mmol g-1, respectively[25], were unfavorable for the desired product since they might
accelerate dehydration reactions other than esterification.[26]
Then, 4 types of zeolites were examined for the reaction. Interestingly, it was
found out that H+-zeolite β could accelerate the reaction to yield approx. 80% of
diphenyl succinate (entry 8). Whereas other H+-zeolites including H+-zeolite Y, H+-

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ZSM-5, and H+-mordenite gave extremely low yields, less than 5% (entries 9-11). It is
noted that, among these zeolites, the H+-zeolite β is the only zeolite possessing a
three-dimensional interconnecting channel structure, and which might be the crucial
contributing factor in its superior activity.[27,28]
The potential catalytic activity of H+-zeolite β was further studied to afford the
highest yield of diphenyl succinate. The catalysis of a class of H+-zeolite β with
different Si/Al ratios (42.2, 104, 150, 440 and 1700) was examined and shown in
Table 2. The acid amount and the yield of diphenyl succinate were plotted against the
Si/Al ratio of the investigated zeolites (See Figure S3). As the decrease of the acid
amount, the yield of diphenyl succinate increased linearly from 30% (entry 1) to about
50% (entry 2) before reaching its peak at approx. 80% (entry 3). However, the
product yield declined markedly when the acid amount continued diminishing
afterward. Particularly, in case of Si/Al = 440, the yield of diphenyl succinate was
almost half as high as that of the former (entry 4), while it was only 3% with Si/Al =
1700 (entry 5). To understand the effect of surface area on the catalyst reactivity,
Argon-adsorption experiments were conducted to determine the Brunauer–Emmett–
Teller (BET) surface. However, the H+-zeolites β with different Si/Al ratio showed
similar surface areas which cannot account for their differences in activities towards
the target reaction.
The catalytic activity of H+-zeolite β with Si/Al = 150 was tested in different
solvents (Table 3). It was observed that the non-polar solvents are suitable for this
catalytic system. Notably, the highest catalyst activities could be achieved in toluene
and heptane solvents, affording 79% and 74% yields of diphenyl succinates,
respectively (entries 1 and 2). Since the boiling points of cyclohexane and hexane are
relatively low, the catalyst showed an inferior activity, providing 24% and 16% yields,

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respectively, of the desired product (entries 3 and 4). In comparison, polar solvents
such as 1,4-dioxane, ethyl acetate, and acetonitrile are not favorable for the present
method, which failed to give the target product (entries 5-7). These results might be
attributable to the highly polar nature of the investigated solvents which is likely to
cause the formation of a hydrogen bond between the protonic site of the catalyst and
the solvents.[29]
On the basis of the favorable conditions (Si/Al ratio and solvent), time course
experiments were carried out to evaluate the progression of the desired product.
Figure 3 showed that the greater yield of diphenyl succinate could be generated after
a longer reaction period. From the result, it is clear that the reaction rate was relatively
high during the first six hours. Particularly, about 40% yield was achieved after 2 h
reaction and it significantly increased after 4 h and 6 h of reaction time, approx. 60%
and 80%, respectively. Those figures increased slightly after continuing the reaction
for 10 h, 12 h, and 24 h, which respectively resulted in 86%, 90%, and 96% yield of
diphenyl succinate. As a representative example regarding the conversion of succinic
acid, after 24 h of reaction period the reaction mixture was further analyzed by a
High-Performance Liquid Chromatography (HPLC, see Supplementary data for the
detailed procedure). The results revealed that 99% succinic acid and 65% phenol were
converted into 96% yield of diphenyl succinate without the formation of monoester
which was confirmed by Gas Chromatography–Mass Spectrometry (GC-MS, Figure
S4).[30]
To evaluate the stability and recyclability of the catalyst, after the first run it
was regenerated and reused for further runs. Simply, the used catalyst was filtered and
washed with water before being dried in an oven at 110 °C for overnight.
Subsequently, it was calcined at 500 °C for 5 h and reused for a new cycle. Detailed

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information is shown in Table S1. As shown in Figure 4, it was clearly observed that
the catalyst could be recycled and used for 5 consecutive runs without considerable
loss in its activity.
Additionally, the catalyst was effective for the esterification of phenol with
other dicarboxylic acids such as malonic acid, adipic acid and glutaric acid (Table 4).
Particularly, good yields of isolate diphenyl glutarate and diphenyl adipate, 76% and
63%, respectively, were achieved with high purity, while those figure for diphenyl
malonate was just about 40% after 24 h of the reaction period (entries 1-3).
4. Conclusions
This paper demonstrated the formation of diphenyl succinate via the
esterification of succinic acid with unreactive phenol using heterogeneous acid
catalysts. The target product was successfully synthesized in the presence of H+-
zeolite β as a solid acid catalyst. The favorable Si/Al ratio of zeolite β and the
dependences of the product yield on the solvent, reaction time were clarified. The
highest yield of diphenyl succinate, 96%, was achieved over zeolite β (Si/Al = 150) in
toluene solvent after 24 h of the reaction period.
The remarkable features of this heterogeneous system are the catalyst
reusability and the capability to effectively accelerate the esterification of several
dicarboxylic acids such as glutaric acid, adipic acid, and malonic acid with phenol to
correspondingly produce diphenyl glutarate, diphenyl adipate, and diphenyl malonate
with good and moderate yields.
Acknowledgments

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This study was supported by JSPS-KAKENHI for Young Scientists (A) (grant no.
17H04966), Japan. S.D. Le greatly appreciates the financial support from INOAC
International Education and Scholarship Foundation, Japan. Various types of
Amberlyst resins were cooperatively supplied by Organo Co., Japan.
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Scheme 1. Synthesis of diphenyl succinate from succinic acid and phenol over H+-
zeolite β
Table 1. Catalyst screening for the synthesis of diphenyl succinatea
Phenol conv.
Entry
Catalyst
Al3+-mont
Yield /%b
Sel. /%b
83
/%b
1
2
3
4
5
6
7
8
9
8
10
7
Zr4+-mont
7
67
Cu2+-mont
3
4
89
Amberlyst-46
Amberlyst-35
Amberlyst-15
Amberlyst-45
H+-zeolite β (150)
H+-zeolite Y (100)
33
33
36
25
51
11
42
30
29
24
79
4
85
61
54
64
>99
25

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10
11
H+-ZSM-5 (90)
3
5
1
22
2
H+-mordenite (240)
<1
aReaction conditions: succinic acid (1 mmol), phenol (3 mmol), dehydrated toluene (5 mL),
catalyst (0.1 g), reaction time (6 h), temperature (reflux). Montmorillonites were dried at
110 °C, while zeolites were calcined at 500 °C for 5 h before use. Other catalysts were used
without any pre-treatment. Numbers in parentheses are the Si/Al ratios.
bDetermined by GC.

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Table 2. Effect of Si/Al ratio in H+-zeolite β on the synthesis of diphenyl succinatea
Surface
areac /m2 g-
Phenol
conv.
/%d
26
Acid amountb
/mmol g-1
Yield
/%d
Entry
Si/Al
Sel. /%d
1
509
592
576
552
544
1
2
3
4
5
42.2
104
0.482
0.252
0.153
0.067
0.028
30
51
79
44
3
77
89
38
150
51
>99
92
440
32
1700
18
11
aReaction conditions: succinic acid (1 mmol), phenol (3 mmol), dehydrated toluene (5 mL),
catalyst (0.1 g), reaction time (6 h), temperature (reflux). Catalysts were calcined at 500 °C
for 5 h before use.
bAcid amount was determined by using NH3-TPD with water vapor treatment (See Figure
S5).
cThe Brunauer–Emmett–Teller (BET) surface area was determined by Argon-Adsorption
using BELSOPR-max analyzer.
dDetermined by GC.
Table 3. Effect of solvent on the synthesis of diphenyl succinate over H+-zeolite βa
Boiling point
/°C
Phenol conv.
Entry
Solvent
Yield /%b
Sel. /% b
/%b
1
2
3
4
5
6
7
Toluene
Heptane
110.6
51
79
74
24
16
0
>99
99
76
30
0
98.4
50
Cyclohexane
Hexane
80.7
21
68.5-69.1
101.1
35
1,4-dioxane
Ethyl acetate
Acetonitrile
n.d
n.d
n.d
77.1
0
0
81.3-82.1
0
0
aReaction conditions: succinic acid (1 mmol), phenol (3 mmol), solvent (5 mL), H+-
zeolite β (Si/Al = 150, 0.1 g), reaction time (6 h), temperature (reflux). The catalyst
was calcined at 500 °C for 5 h before use.
bDetermined by GC.
n.d indicates not determined

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100
90
80
70
60
50
40
30
20
10
0
90
86
96
79
57
38
0
5
10
15
20
25
Time /h
Figure 3. Time course of the synthesis of diphenyl succinatea
aReaction conditions: succinic acid (1 mmol), phenol (3 mmol), dehydrated toluene (5
mL), H+-zeolite β (Si/Al = 150, 0.1 g), temperature (reflux). The catalyst was calcined
at 500 °C for 5 h before use.
80
70
60
50
40
30
20
10
0
1
2
3
4
5
Run
Figure 4. Recycling experiments on the synthesis of diphenyl succinatea
aReaction conditions: Succinic acid: phenol (1:3 mmol), H+-zeolite β (Si/Al = 150, 0.1-0.4 g),
dehydrated toluene (5-20 mL), reaction time (6 h), temperature (reflux). The catalyst was
calcined at 500 °C for 5 h before each use.
Table 4. Esterification of dicarboxylic acids with phenol over β-zeolitea

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Entr
y
Dicarboxylic
Isolated yield
/%b
Purity /%c
Diphenyl dicarboxylate
acid
1
2
3
Glutaric acid
Diphenyl glutarate
Diphenyl adipate
Diphenyl malonate
76
63
37
100
Adipic acid
100
96
Malonic acid
aReaction conditions: Succinic acid (1 mmol), phenol (3 mmol), dehydrated toluene (5 mL),
reaction time (24 h), H+-zeolite β (Si/Al = 150, 0.1 g), temperature (reflux). The catalyst
was calcined at 500 °C for 5 h before use.
bIsolated yields were calculated based on the initial mole of the corresponding dicarboxylic
acid.
1
cPurity of the obtained product was estimated by H-NMR with an internal standard, maleic
acid, as described in the Supplementary data.

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Highlights



Esterification of succinic acid with phenol producing 96% yield of the diester.
Zeolite β showed remarkable activity and excellent recyclability.
A facile approach to synthesize diphenyl dicarboxylates from dicarboxylic
acids.