Jurnal Akademika Kimia, 14(2): 77-82, May 2025
ISSN (online) 2477-5185 | ISSN (print) 2302-6030
http://jurnal.fkip.untad.ac.id/index.php/jak/

OPEN ACCESS

1

Epoxidation of Eugenol from Clove Oil (Syzygium aromaticum) Using
H₂O₂ Oxidizer and H₃PO₄ Catalyst
*Walburga E. Gheje, Paulus H. Abram, Vanny M. A. Tiwow, & Sitti Rahmawati

Chemistry Education Study Program/Faculty of Teacher Training and Education – Universitas Tadulako, Palu –
Indonesia 94119
Received 16 March 2025, Revised 28 March 2025, Accepted 04 April 2025
doi: 10.22487/j24775185.2025.v14.i2.pp77-82

Abstract
Clove oil (Syzygium aromaticum) contains 80–90% eugenol. Eugenol is a pale yellow liquid with several active functional
groups, such as hydroxyl, aromatic rings, and allyl groups, which allow it to be modified to produce various eugenol derivative
compounds. This study aims to characterize eugenol epoxy resin synthesized from clove oil eugenol using hydrogen peroxide (H₂O₂)
and phosphoric acid (H₃PO₄) as a catalyst. The resulting eugenol epoxide was in the form of a yellowish-white gel with a distinctive
clove aroma. It was soluble in benzene and chloroform but insoluble in ethanol. FTIR analysis showed that the epoxy compound
contained an ether group (C-O-C) at absorption peaks of 1266.07 cm⁻¹ to 1018.66 cm⁻¹, a hydroxyl group (─OH) at 3347.08
cm⁻¹, a methyl group (-CH₃) at 1470 cm⁻¹ to 1350 cm⁻¹, an alkene group (C=C) at 1637.39 cm⁻¹, and a vinyl group at 910.2
cm⁻¹.
Keywords: Catalyst, clove oil, epoxidation, eugenol

4-allyl-2-methoxyphenol. Its aromatic structure
consists of a benzene ring containing a hydroxyl
group (–OH), a methoxy group (–OCH₃), and an
allyl side chain (–CH₂–CH=CH₂), which together
contribute to the distinctive clove aroma and its
potent biological activities (Matykiewicz &
Skórczewska, 2022). Derivative compounds include
methyl eugenol, isoeugenol, and synthetic vanilla.
Another widely used modification of eugenol is
polyeugenol, derived from the eugenol
polymerization process.
Polyeugenol is produced by polymerization
by addition. Polyeugenol is a derivative compound
of eugenol, often used as a carrier in metal
separation methods and for various other
applications. This increases the need for
polyeugenol in industry and research (Rahim, 2022).
In addition to polymerization, the synthesis of other
eugenol-derived compounds can also be modified
by methods such as epoxidation. Epoxidation is a
chemical reaction in which organic compounds
containing double bonds (alkenes or alkynes) react
with epoxy (oxidant or ethoxyne) to form cyclic
compounds called epoxides. Epoxidation generally
involves oxidative reagents such as peroxide or
other oxygen compounds. This process is often
used in organic synthesis to produce a variety of
compounds, including a useful epoxide.

Introduction
Indonesia is rich in various spice plants,
widely distributed across different regions, offering
significant potential for sourcing raw materials to
produce essential oils like clove. Clove has long
been used in the health sector, particularly in
pharmaceuticals. It is employed in treating coughs,
headaches, epilepsy, as a sleep inducer, a blood
thinner, and a mental stimulant. Additionally, clove
is an active ingredient in several mouthwashes used
to relieve toothache pain, and it aids in stimulating
blood circulation throughout the body (Ticoalu et
al., 2024).
Clove oil can be obtained from clove buds
(clove oil), clove stems (clove stem oil), and clove
leaves (clove leaf oil). The main component of clove
oil is eugenol, which is widely used in medicine and
possesses antioxidant, antimicrobial, antiviral,
antinociceptive, analgesic, anesthetic, antiinflammatory, and wound-healing properties. The
essential oil content in clove buds reaches up to
21.3%, with eugenol content ranging from 78–95%;
from clove stems around 6%, with 89–95%
eugenol; and from clove leaves approximately 2–
3%, with eugenol levels between 80–85% (Lestari et
al., 2023).
Eugenol is a phenolic compound with the
molecular formula C10H12O2, chemically known as

⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯

*Correspondence:
Walburga E. Gheje
e-mail: walburgaedeltrudis@gmail.com
© 2025 the Author(s) retain the copyright of this article. This article is published under the terms of the Creative Commons
Attribution-NonCommercial-ShareAlike 4.0 International, which permits unrestricted non-commercial use, distribution,
and reproduction in any medium, provided the original work is properly cited.

77

Walburga E. Gheje et al.

According to Standau et al. (2021), epoxy
refers to compounds or polymers containing
epoxide groups, particularly epoxy resins, which are
used as adhesives, coatings, or composites due to
their adhesive properties and chemical resistance. In
the industrial context, epoxy is a product of the
chemical industry, produced by epoxidizing alkenes
(such as ethylene oxide from ethylene) for the
synthesis of glycols, polyols, or resins. Due to its
superior properties, epoxy is one of the most widely
used polymer materials in various industries.
According to Dong et al. (2021), epoxy possesses
powerful chemical bonds resulting from the threedimensional network structure formed during
curing, making it ideal for applications requiring
high mechanical strength, such as industrial floor
coatings and composite materials. The adhesive
properties of epoxy allow it to bond to various
substrates, including metals, ceramics, and plastics,
with structural bonding strength, which is why it is
extensively used in the automotive and construction
industries.
Regarding chemical resistance, epoxy
exhibits resistance to acids, bases, and organic
solvents. Moreover, epoxy is an effective electrical
insulator, critically important in electronic
components and electrical insulation materials (Li et
al., 2021). Research on eugenol compounds has
been conducted by previous researchers, including
Amin et al. (2023), who characterized the essential
oil composition of Syzygium aromaticum Linn.
(clove) using GC-MS and evaluated its antioxidant
activity. The GC-MS analysis of Clove essential oil
identified 37 chemical compounds, constituting
about 99.49% of the total essential oil. Clove
essential oil was found rich in eugenol (59.87%),
caryophyllene (23.58%), α-selinene (4.67%), αterpinyl acetate (4.12%), and humulene (3.74%).
The Clove essential oil was found to be a potent
antioxidant, with a maximum inhibition of 90.94%,
comparable to standard antioxidant compounds
such as ascorbic acid (92.94%) and gallic acid
(87.80%).
Using response surface methodology,
Margareta & Wonorahardjo (2023) researched
optimizing eugenol isomerization conditions from
clove leaf oil. FTIR analysis of isoeugenol samples
showed the absorption band of the OH group at
3498.87 cm-1 (std. 3496.94 cm-1) and the
absorption band at 2846.93 cm-1 (std. 2846.93 cm-1
which indicates the group OCH3 C-C aryl group
(aromatic ring) at 1598,99 cm-1 (std. 1598,99 cm-1)
and CH3 group at 2935,66 cm-1 (std. 2935,66 cm-1)
While the results of the analysis with HNMR
indicate the position of chemical shift (3) of methyl
group (-CH3) as the identity of isoeugenol
compound which is 1,812 ppm (std. 1,814 ppm) in
the form of doublets for the 3H from -CH3, The
identification results also showed that the
isoeugenol obtained was more dominant in the
form of trans isoeugenol. FTIR spectra showed that

the absorption band of trans-isoeugenol (=CH) was
962.4 cm-1, whereas the cis-isoeugenol was 792,7
cm-1. The results of the HNMR spectrum for the
peak of H were located at ppm 3=6.1. and a=5,95.
Guntarti et al. (2024) researched the
authenticity of clove leaf oil in products (Syzygium
aromaticum (L.) Merr. & L. M. Perry) using GC-MS
and FTIR methods combined with chemometrics.
The constituents’ presence in distilled clove oil from
GC-MS analysis was eugenol (49.63%), βCaryophyllene (28.25%), alpha-Humulene (8.92%),
alpha-Copaene (2.15%), delta-Cadinene (1.61%),
and
Caryophyllene
oxide
(1.50%).
Six
concentrations were prepared for FT-IR analysis of
a mixture of clove leaf oil and turpentine oil, which
was estimated by PLS and PCA chemometrics.
Turpentine oil was used as a counterfeit, typically
added to clove oil products. The PLS analysis of
FTIR obtained optimized wavenumbers, 2960-2860
cm-1. The equation y=0.9998x+0.0096 had an R2
value of 0.9998 and RMSEC, RMSECV, and
RMSEP values of 0.22%, 0.76%, and 1.20%,
respectively. The PCA analysis can categorize the oil
based on the main component types of distilled
clove leaf oil, turpentine oil, market oil, products A,
B, and C. The results showed product A was in the
same quadrant as distilled clove leaf oil. Moreover,
no clove leaf oil product had physical and chemical
characteristics similar to turpentine oil.
Based on the background, the researcher is
interested in researching the eugenol epoxidation of
clove oil (Syzygium aromaticum) using an oxidizer
H2O2 with an H3PO4 catalyst because the
researchers have never observed the eugenol
epoxidation of clove oil (Syzygium aromaticum)
using an oxidizer H2O2 with an H3PO4 catalyst.
Methods
The tools used in this study were 100 ml
beaker (Pyrex), 50 ml beaker (Pyrex), 10 ml
measuring cup (Pyrex), hot plate (Robusta), digital
scale (Sonic Electronic), FTIR (Bruker Alpha 2 ECOATR), drip pipette, spray bottle, stirring rod, a
thermometer (Pyrex), spatula, watch glass, mortar
and pestle, test tube and tube rack. Meanwhile, the
ingredients used were eugenol, 4 ml of H2O2 30%,
85% H3PO4, 1 ml, 2.5 ml of benzene, 2.5 ml of
ethanol, 2.5 ml of chloroform, 2 ml of glycerin, 2 ml
of propylene glycol, 3 grams of CMC-Na, and 30 ml
of aqua. The sample used was eugenol and clove oil,
obtained from a medical device store in Surabaya.

Eugenol epoxy manufacturing

A total of 2 ml of eugenol is placed into the
chemical glass of the test tube, followed by the
addition of 4 ml of H2O2 as an oxidizer, and the
mixture is stirred using a stirring rod. Then, slowly
add 1 ml of H3PO4 solution while stirring until the
solution thickens. Next, the solution mixture lasts
15 minutes until two layers are formed. Separate the
two layers of solution (Hikmah et al., 2018).

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Jurnal Akademika Kimia

Eugenol epoxy gel manufacturing

in the epoxy evaporates, facilitating the washing
process. Furthermore, the epoxy gel is washed twice
with an aqueous solution until the washing water
becomes clear. This indicates that the eugenol epoxy
gel is free of any remaining impurities. Then the
epoxy gel that has been washed is transferred into
the gel container that has been prepared and left to
sit for 1 x 24 hours to maintain the gel's moisture,
improve the gel's structure, and prevent drying.
Next, a solution of eugenol epoxy is added and
stirred until homogeneous. Then the epoxy gel
formed is left for 1 x 24 hours at room temperature
so that the solvent in the epoxy evaporates,
facilitating the washing process. Furthermore, the
epoxy gel is washed twice with aqueous solution
until the washing water becomes clear, indicating
that the eugenol epoxy gel is free of any remaining
impurities. Then the epoxy gel that has been washed
is transferred to the gel container that has been
prepared and left for 1 x 24 hours at room
temperature so that the epoxy gel is free of moisture
content.
This study characterized the eugenol
polymerization process by observing the solution's
thickening and a slow temperature increase, as the
reaction was exothermic. In contrast to the research
conducted by Hikmah et al. (2018), the
polymerization process is characterized by the
release of smoke and thickened polymers. The final
result of this process is a yellowish-white epoxy
compound in gel form that smells like cloves. The
results of eugenol epoxidation using hydrogen
peroxide oxidizers and phosphoric acid catalysts are
shown in Table 1.

Put 3 grams of CMC-Na, which has been
weighed into a lump, into 30 ml of aquades at a
temperature of 70 °C. Stir until it forms a gel, then
add 1 ml of glycerin and 1 ml of propylene glycol
while continuing to stir. Then add the eugenol
epoxy solution and stir until homogeneous. The
epoxy gel is left to sit for 24 hours at room
temperature to allow the solvent to evaporate, and
then it is washed twice. After washing, the epoxy gel
is transferred to the prepared container and left to
sit for 24 hours at room temperature (Purgiyanti &
Pratiwi, 2018).

Solubility testing

The solubility test was carried out by
dissolving 0.25 grams of epoxide each into 3 test
tubes. In each test tube, 2.5 ml of organic solvents
—benzene, ethanol, and chloroform —were added
successively and then mixed. The solubility of each
test tube was observed.

Characteristics of eugenol epoxy using FTIR

Eugenol epoxy analysis was performed using
the
Fourier
Transform
InfraRed
Spectrophotometer (FT-IR) to examine the
functional groups contained in eugenol.
Results and Discussion
This study aims to determine the epoxide
character of the epoxidation results using a
hydrogen peroxide oxidizer (H2O2) and a
phosphoric acid catalyst (H3PO4). It consists of
several stages (Hikmah et al., 2018).

Eugenol epoxidation with hydrogen peroxide
oxidizer and phosphoric acid catalyst

Table 1. Physical data of eugenol epoxidation
results using hydrogen peroxide oxidizer and
phosphoric acid catalyst

Epoxidation is carried out by reacting
eugenols, oxidizers, and catalysts in a chemical glass.
The oxidizers and catalysts used are hydrogen
peroxide and phosphoric acid. Epoxidation is
carried out by mixing 2 ml of clove oil and 4 ml of
H2O2 (hydrogen peroxide) into a beaker while
stirring. The addition of hydrogen peroxide is an
oxidizer in the eugenol synthesis process. Next,
slowly add 1 ml of phosphoric acid (H3PO4) while
stirring until the solution thickens. The addition of
phosphoric acid as a catalyst serves to accelerate the
eugenol reaction process. After that, let the eugenol
solution mixture sit for 15 minutes until 2 layers are
formed, where the top layer is light yellow eugenol
epoxy and the bottom layer is water.
Next, in a separate container, place 3 grams
of CMC-Na, which has been weighed into a lump,
along with 30 ml of aquades at a temperature of 70
°C. Stir until a gel forms, then add 1 ml of glycerin
and 1 ml of propylene glycol while continuing to
stir. Adding glycerin and propylene glycol aims to
maintain the gel's moisture, improve the gel's
structure, and prevent drying. Next, a solution of
eugenol epoxy is added and stirred until
homogeneous. Then the epoxy gel formed is left for
1 x 24 hours at room temperature so that the solvent

What is Observed

Eugenol Epoxide

Existed

Gel

Color

Yellowish white

Smell

Clove smell

Solubility testing

Table 2 presents the solubility test results of
epoxy compounds obtained from eugenol
epoxidation with hydrogen peroxide and
phosphoric acid, using benzene, chloroform, and
ethanol solutions.
Table 2. Solubility test results
Solution

Solubility

Benzene

Soluble

Chlorophen

Soluble

Ethanol

Insoluble

In this study, the epoxy compounds formed
were each weighed to 0.5 grams and then poured
into three test tubes of 0.5 grams each. Each test
tube is filled with 2.5 mL of benzene, chloroform,
and ethanol solvent and shaken until the epoxy is

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Walburga E. Gheje et al.

completely dissolved. After that, the three tubes
were observed, and the results from the solubility
test showed that polyeugenol compounds were not
soluble in ethanol. However, epoxy compounds are
highly soluble in chloroform and benzene
(Ghumman et al., 2021). Where polyeugenol is not
soluble in water, n-hexane, and benzene but in
ethanol, ethyl acetate, and chloroform, this is
influenced by the polar properties of different
solvents, where ethanol and polyeugenol are nonpolar, so neither reacts well. At the same time,
benzene and chloroform are nonpolar, so that it can
dissolve nonpolar epoxy compounds. The factors
that affect the solubility of epoxy are the size
difference between the epoxy and the solvents,
temperature, and volume (Tulegenkyzy et al., 2024).

absorption area of 1470 cm⁻¹ - 1350 cm⁻¹ is the –
CH3 bend group. The bands in the 1266.07 cm⁻¹ to
1018.66 cm⁻¹ show vibrations from the C–O–C
group, characteristic of both epoxy and ether
groups. The presence of this band indicates that the
epoxidation process is successfully underway. If the
epoxy ring is opened, hydroxyl and ether groups will
be formed, showing absorption in this area
(Kamairudin et al., 2021). Furthermore, a vinyl
group is on the 910.2 cm⁻¹ absorption tape.
The FTIR spectrum results showed the
success of the epoxidation reaction, which was
characterized by the appearance of epoxy groups at
wave numbers of 1266.07 cm⁻¹ to 1018.66 cm⁻¹ and
hydroxyl groups at wave numbers of 3347.08 cm⁻¹.
The absence of significant changes in the aromatic
absorption band suggests that eugenol's main
structure remains intact. The reaction, using
hydrogen peroxide as an oxidizer and phosphoric
acid as a catalyst, does not damage the structure of
the aromatic ring. Instead, it adds the desired polar
group through epoxidation.

FTIR characteristic

This study used FTIR (Fourier Transform
Infra-Red) spectroscopy to identify the functional
groups in the compounds resulting from the
eugenol epoxidation reaction, which used hydrogen
peroxide as an oxidizer and phosphoric acid as a
catalyst. The obtained spectrum showed several
distinctive absorption bands that indicated the
presence of specific clusters. The results of the
eugenol epoxy analysis in this study can be seen in
Figure 1.

FTIR results comparison

In the analysis of chemical compounds, the
FTIR (Fourier Transform Infrared) spectrum is an
important method for identifying functional groups
based on the absorption of infrared waves by
molecules (Gong et al., 2024). Each functional
group has a typical wavenumber range that can be
compared with the literature data to ensure the
suitability of the structure of the compound being
analyzed. In this section, a comparison was made
between the results of the FTIR spectrum of the
synthesized eugenol sample and the literature data
as a reference. The aim is to validate the existence
of the main functional groups present in eugenol
structures, such as hydroxyl (–OH) groups, ethers
(–OCH₃), alkenes (C=C), and aliphatic groups (–
CH₃ and –CH₂–). By comparing the number of
waves in the analysis spectrum with those in the
literature, conclusions can be drawn about the
success of the synthesis process and the purity of
the resulting compounds. This comparison is an
important step in ensuring that the FTIR results
accurately represent the chemical structure of
eugenol and are in accordance with scientific
standards (Agrawal et al., 2022). A comparison of
the wavelengths in the FTIR spectrum of eugenol
epoxide is shown in Table 3.

Figure 1. FTIR spectrum
The absorption band at 3347.08 cm⁻¹
indicates the presence of a –OH (hydroxyl) group
(Dai et al., 2023), which is most likely formed due
to the epoxy ring's opening or the alkene group's
oxidation. This hydroxyl group is not abundant in
pure eugenol, so its presence indicates the
occurrence of chemical reactions during the
epoxidation process. The band at 2926.98 cm⁻¹
absorbs the aliphatic C–H group strain vibrations
(Ding et al., 2024), which originate from the methyl
and methylene groups in the molecular side chains
(Lorenz-Fonfria, 2020). This band is commonly
found in organic compounds and indicates the
presence of saturated hydrocarbon structures. The
strong absorption band at 1637.39 cm⁻¹ indicates
the presence of an aromatic C=C group, indicating
that the benzene ring structure of eugenol is still
maintained after the reaction process. In the

Table 3. Comparison of the FTIR spectrum with
previous research (Hikmah et al., 2018)
Number of Waves (cm-1)
Hikmah et al.
Spectrum Results
(2018)
3448.72
3347.08
3518.1
2926.98
1604.7 - 1512.1
1637.38
2908.6 - 2839.2
1470 - 1530
1265.3
1255.07 – 1018.66
910.40 - 995.27
910.2

80

Function Clusters
O-H
C-H stretch
C=C aromatic
-CH3 bend
C-Eter
Vinyl Cluster

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Jurnal Akademika Kimia
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Based on the results of the comparative
analysis of the FTIR spectrum, the synthesis results,
as well as the research conducted by Hikmah et al.
(2018), did not show significant differences. Major
functional groups such as –OH, C–O ether, and
aromatic C=C are detected at comparable
wavelengths. For example, the absorption band for
the -OH group appears at 3347.08 cm⁻¹, which is
comparable to the study conducted at a wave
number of 3448.72 cm⁻¹. In addition, the aromatic
C=C group was detected at 1737.39 cm⁻¹, similar to
the value obtained in the 1604.7 – 1512.1 cm⁻¹
range. The C–O ether group was also identified
through the absorption of 1255.07 – 1018.66 cm⁻¹,
close to the value obtained 1265.3 cm⁻¹. The
synthesized compounds, obtained by reacting clove
oil with hydrogen peroxide oxidizers (H2O2) and
using phosphoric acid catalysts (H3PO4), exhibit
absorption characteristics that represent the
functional groups in eugenol.
Conflict of Interest
The authors have confirmed that no
competing interests exist concerning the posting of
this paper.
Acknowledgments
The author would like to thank the
Chemistry Laboratory of FKIP Tadulako University
and all parties who helped the author complete this
research.
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