Chemical Modification Of Polyphenol And Its Application For Wood Treatment Natural Catechin Modification

CHEMICAL MODIFICATION OF POLYPHENOL AND ITS
APPLICATION FOR WOOD TREATMENT: NATURAL
CATECHIN MODIFICATION

FEBRINA DELLAROSE BOER

GRADUATE SCHOOL
BOGOR AGRICULTURAL UNIVERSITY
BOGOR
2017

STATEMENT
I declare that this thesis, entitled Chemical Modification of Polyphenol
and Its Applications for Wood Treatment: Natural Catechin Modification, is my
own work with the direction of the supervising committee and has not been
submitted in any form for any college except in AgroParisTech centre de Nancy
and Université de Lorraine, France (required by the Double Degree Master
Program—the joint Master program held between the Program Study of Forest
Products Science and Technology of Bogor Agricultural University and Bois
Forêt et Développement Durable of AgroParisTech centre de Nancy and
Université de Lorraine). Information and quotes from journals and books have

been acknowledged and mentioned in the thesis where they appear. All complete
references are given at the end of the paper.
I understand that my thesis will become part of the collection of Bogor
Agricultural University. My signature below gives the copyright of my thesis to
Bogor Agricultural University.

Bogor, Februari 2017
Febrina Dellarose Boer
NIM E251140031

SUMMARY
FEBRINA DELLAROSE BOER. Chemical Modification of Polyphenol and Its
Application for Wood Treatment: Natural Catechin Modification. Supervised by
DODI NANDIKA and CHRISTINE GÉRARDIN.
Catechin is one of the naturally-occurred polyphenols which possesses
powerful scavanger related to its antioxidant trait. Catechin itself can be modified
to increase its potential utilization with several compounds such as epoxy resin
through urethane synthesis and fatty acids through esterification. With the current
trend of increasing efforts to develop non-isocyanate-based polyurethanes
(NIPUs), the first objective of this study is to chemically modify catechin in order

to synthesize the urethane. Meanwhile, in order to develop an environmental
friendly wood preservative, the second objective of this study is to chemically
modify the catechin’s hydroxy groups with the fatty acid chains in the context of
its potential utilization as a wood preservative.
The methods used in the urethane synthesis consisted of four steps:
glycidilation of catechin, hydrolysis of epoxide, carbonate synthesis, and a test for
carbamate synthesis through condensation of butylamine. The resulting products
then analyzed and characterized using FTIR (Fourier Transform Infrared) and
NMR (Nuclear Magnetic Resonance) spectroscopy. It was determined that we
have successfully obtained carbamate (urethane) with a model amine (butylamine)
through this four-steps method, thus opening the door to further polyurethane
synthesis using the modification of catechin.
Meanwhile, the esterification study has evaluated the methods of grafting
commercial catechin with three types of fatty acids: capric acid (C10), myristic
acid (C14), and lauric acid (C12). Specimens of beech wood (Fagus sylvatica L.)
were impregnated by both the catechin and modified catechin at 5% concentration
level using vacuum pressure treatment and subjected to leaching. Specimens were
tested against white rot fungi Corioulus versicolor for twelve weeks. Catechin
modified with C10, C12, and C14 fatty acids were evaluated through the analysis
of their weight percent gain before (WPG) and after leaching (WPAL), percentage

of leaching (PL), and the decay resistance of treated and untreated sample before
and after leaching exposed to C. versicolor. Results show that the specimens
treated with catechin modified with fatty acids possess significant results on PL
while the specimens treated with catechin—C14 present best PL after the leaching
compared to the others. It is believed that the addition of fatty acid, and the
increasing length of its chain, will lead to the increasing of the leaching resistance.
However, it is recommended to increase the concentration level of modified
catechin for obtaining the significant effect on the decay resistance.
Key words : biobased compound, catechin, chemical modification, fatty acids,
isocyanate-free, polyurethane, wood preservation.

RINGKASAN
FEBRINA DELLAROSE BOER. Modifikasi Kimia Senyawa Polifenol dan
Aplikasinya pada Perlakuan Kayu: Modifikasi Katekin Alami. Dibimbing oleh
DODI NANDIKA dan CHRISTINE GÉRARDIN.
Katekin merupakan salah satu polifenol alami yang dikenal karena sifat
antioksidannya. Katekin sendiri dapat dimodifikasi dengan tujuan untuk meningkatkan potensi kegunaannya dengan berbagai senyawa lain, seperti resin epoksi,
melalui sintesis uretan dan asam lemak melalui reaksi esterifikasi. Dengan meningkatnya usaha dalam mengembangkan poliuretan bebas isosianat (NIPUs),
tujuan pertama dalam penelitian ini adalah untuk memodifikasi katekin secara
kimiawi dengan tujuan untuk sintesis uretan. Sementara itu, untuk pengembangan bahan pengawet kayu ramah lingkungan, tujuan kedua dari penelitian ini

adalah untuk memodifikasi secara kimia gugus hidroksi katekin dengan rantai
asam lemak dalam konteks kegunaannya sebagai bahan pengawet kayu.
Metode yang digunakan dalam sintesis uretan, terdiri dari empat langkah:
glisidasi katekin, hidrolisis epoksida, sintesis karbonat, dan sintesis karbamat.
Produk yang diperoleh kemudian dianalisis menggunakan alat spektroskopi FTIR
(Fourier Transform Infrared) dan NMR (Nuclear Magnetic Resonance). Hasil
penelitian menunjukkan bahwa melalui keempat metode tersebut, penelitian ini
telah berhasil memperoleh karbamat (uretan) dengan menggunakan model
aminasi sederhana (butilamin), yang membuka peluang ke depan dalam penelitian
lebih lanjut.
Sementara itu, dalam proses esterifikasi telah dievaluasi metode grafting
menggunakan katekin komersial dengan tiga macam asam lemak: asam kaprat
(C10), asam miristat (C14), dan asam laurat (C12). Selanjutnya sampel kayu
beech (Fagus sylvatica L.) diimpregnasi dengan menggunakan katekin dan
katekin termodifikasi pada konsentrasi 5% dengan menggunakan proses vakum
kemudian diberikan perlakuan pencucian sesuai standar ENV 1250-2. Contoh uji
kayu kemudian diuji ketahanannya terhadap jamur pelapuk putih Corioulus
versicolor selama dua belas minggu. Efektivitas katekin yang dimodifikasi dengan
asam lemak C10, C12, dan C14 dievaluasi melalui pengukuran Weight Percent
Gain (WPG) sebelum dan sesudah pencucian, persentase ketercucian (Percentage

of Leaching, PL), dan ketahanan terhadap jamur Corioulus versicolor sebelum
dan sesudah pencucian. Hasil penelitian menunjukkan bahwa sampel kayu yang
dimodifikasi dengan asam lemak memiliki penurunan nilai PL yang signifikan.
Dalam hal ini, sampel yang diberi perlakuan katekin—C14 memiliki nilai WPG
yang lebih tinggi, ketercucian paling rendah, dan ketahanan jamur yang lebih
tinggi dibandingkan dengan perlakuan lainnya. Hal ini menunjukkan bahwa
penambahan rantai asam lemak pada katekin dapat meningkatkan efektivitasnya
sebagai bahan pengawet kayu khususnya dalam meningkatkan ketahanan kayu
beech terhadap pencucian. Untuk penelitian selanjutnya, disarankan untuk
meningkatkan konsentrasi katekin termodifikasi untuk mendapatkan tingkat
ketahanan kayu terhadap jamur yang signifikan.
Kata kunci

: asam lemak, bebas isosianat, katekin, modifikasi
pengawetan kayu, poliuretan, senyawa berbasis biologis

kimia,

©Copyright IPB, 2017
Copyright Reserved by Law

Prohibited quoting part or all of this paper without mentioning or citing the
sources. Quotation is only for educational purposes, research, writing papers,
preparing reports, writing criticism, or review of an issue, and the citations will
not harm the interests of IPB
Prohibited to publish and reproduce part or all of this paper in any form without
IPB permission

CHEMICAL MODIFICATION OF POLYPHENOL AND ITS
APPLICATION FOR WOOD TREATMENT: NATURAL
CATECHIN MODIFICATION

FEBRINA DELLAROSE BOER

Thesis
In partial fulfillment of the requirements for the degree of
Master of Science
at
Forest Products Science and Technology Study Program

GRADUATE SCHOOL

BOGOR AGRICULTURAL UNIVERSITY
BOGOR
2017

External Examiner: Dr Ir Akhmad Endang Zainal Hasan, MSi

FOREWORD
All praise and gratitude to Allah SWT so that this scientific work, entitled
Chemical Modification of Polyphenol and Its Application for Wood Treatment:
Natural Catechin Modification, could be finished. The study is expected to
provide scientific information on the methods of the modification of catechin in
order to improve its utilization.
I would first like to thank my supervisor, Professor Dodi Nandika and
Professor Christine Gérardin, for their expert advices and encouragement
throughout this work, as well as Dr. Hubert Chapuis for his helpfulness and
guidance in both technical and practical ways on my work.
My study has been impossible to complete without the support from the
Ministry of Education and Culture of Indonesia (Kementerian Pendidikan dan
Kebudayaan Indonesia) in the form of a scholarship, ―Beasiswa Unggulan‖, which
supported my double degree Master education both in Indonesia and France, and

CampusFrance with French Ministry of Foreign Affairs for their social coverage
scholarship. I would also like to thank Prof. Wayan Darmawan, Prof. Philippe
Gérardin, Prof. Mériem Fournier, and Dr. Holger Wernsdörfer for their support
and assistance during my study both in Indonesia and in France.
I would also like to thank to my colleagues, especially in LERMaB,
Nancy, France: to Aurélia Imbert, Thomas, and Wissem Sahmim for their help in
the laboratory and inputs during my internship. To my lab-mates: Azza Zeriaa,
Marwa Ben Hasinne, Amal Ben Hadj, and Huo Wenjie, for the sweet friendship
during my stay in Nancy, and encouragement in every crisis moment.
Finally I would like to sincerely thank my parents and all of my family, for
their love and support during my study.
I recognize that this paper is still far from perfect. Therefore, suggestions
and constructive criticism are expected to improve this work.

Bogor, Februari 2017
Febrina Dellarose Boer

TABLE OF CONTENTS
TABLE OF CONTENTS

vi

LIST OF TABLES

vi

LIST OF FIGURES
1 INTRODUCTION
Background
Formulation
Objective
Benefits

1
1
3
3
4

2 MATERIALS AND METHODS

Location and Period of Research
Tools and Materials
Data Analyzing

4
4
4
9

3 RESULTS AND DISCUSSIONS
Reaction of Catechin and Epoxide
Grafting of Catechin and Fatty Acid
Application as a Wood Preservative

10
10
16
20

4 CONCLUSIONS

Conclusion
Suggestions

25
25
25

REFERENCES

26

CURRICULUM VITAE

29

LIST OF TABLES
1
2
3
4
5

Classes of natural durability of wood to fungal attack using laboratory
tests based on EN 113
Yield of catechin modified with fatty acids
Percentage of weight gain after impregnation, weight gain after
leaching, and percentage of leaching
P-value for T-test
Weight loss of beech wood specimens exposed to C. versicolor

9
20
20
22
23

LIST OF FIGURES
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26

Chemical modification of catechin through grafting with link ester.
Illustration of vacuum impregnation of the wood specimens using
desiccator
Leaching process under continuous shaking method based on ENV
1250-2
Reaction of catechin and epichlorohydrin
1
H NMR spectrum of catechin
1
H NMR spectrum after glycidylation of catechin
FTIR transmission spectrum after glycidilation of catechin
Hydrolysis of epoxide
FTIR transmission spectrum: comparison between epoxide and diol
1
H NMR spectrum after epoxide opening reaction (C27H38O14)
Synthesis of cyclic carbonate derivatives (C31H30O18)
FTIR transmission spectrum after carbonation
1
H NMR spectrum after carbonation reaction (C31H30O18)
Synthesis of carbamate with butylamine
Comparison between carbamation followed and unfollowed by a
liquid/liquid extraction step
1
H NMR spectrum after carbamation reaction with butyl amine
(C47H74N4O18)
Catechin
Catechin modified with capric acid (monoester)
Catechin modified with capric acid (diester)
Catechin modified with myristic acid (monoester)
Catechin modified with myristic acid (diester)
Catechin modified with lauric acid (monoester)
Catechin modified with lauric acid (diester)
Boxplot results of WPG, WPAL, and PL
Boxplot results of weight loss for all treated samples
Decay resistance measurements of wood specimens

2
7
8
10
10
10
11
11
12
12
13
13
14
14
15
15
16
16
17
17
18
18
19
21
22
24

1 INTRODUCTION
Background
Lately, many studies aiming to create biobased, environmentally friendly,
and non-toxic green wood preservatives have been conducted. This comes as a
result of environmental issues and regulations pushing the development of new
technologies to create new sustainable wood preservative which also reduces the
utilization of biocide (Schultz et al. 2007; González-Laredo et al. 2015; Pizzi
2016). Not only for that, said studies also focused on creating biobased and green
chemistry polymers, one of them was the effort to develop non-isocyanate based
polyurethanes (NIPUs) by minimizing the utilization of isocyanates in
polyurethane synthesis to reduce the severe toxicity issues (Zhenhua and Dong
2007; Maisonneuve et al. 2015; Datta and Włoch 2016). This is related to the
production of conventional polyurethanes which are prepared through a polyaddition reaction of isocyanates and polyols that remained a major concern as it involved generally the use of toxic petrochemical diisocyanates (Bayer 1947).
The chemical modification of biosourced polyphenols is interesting for its
environmentally friendly traits (Peng et al. 2013; Pizzi 2016; Delgado-Sanchez
2016, Rangel et al. 2016). Catechin, a flavonoid-type compound, is an interesting
molecule to be studied for its natural hydrophilic antioxidant characteristics (Aditya et al. 2015). It has been determined that this molecule has a powerful scavenger concerning to its antioxidant properties which seems to be related to its chemical structure, particularly with the presence of the catechol moiety on ring B and
the presence of a hydroxyl group activating the double bond on ring C (Gadkari
and Balaraman 2015). In the context of said issues, polyphenols such as catechin
have the potential to be developed as a main compound in the synthesis of
isocyanate-free polyurethane (Nouailhas et al. 2011; Aouf et al. 2013; Arbenz and
Averous 2015) and its potency as a wood preservative (Malterud et al. 1985; Laks
et al. 1988).
The idea of utilizing catechin as a main compound in the synthesis of
isocyanate-free polyurethane came from the work by Benyahya et al. (2013) and
Thébault et al. (2014). In their study, natural polyphenols were used to replace
bisphenol A, the most common phenol derivative used in epoxy resin formulations (Benyahya et al. 2013); and to replace isocyanate, the main compound in the
making of polyurethane (Thébault et al. 2014). The methods used by Benyahya et
al. (2013) led to the modification of catechin towards the synthesis of epoxide
through glycidilation process. Additionally, the methods used by Thébault et al.
(2014) was able to carry the synthesis towards the formation of urethane from
tannins. The link between these two methods lies on the hydroxyl group which,
through additional modification, may be changed from epoxy towards carbonate
cyclic. This can be conducted through epoxide hydrolysis, which opens the
epoxide ring (Wang et al. 2008), and continued using synthesis carbonate using
dimethyl carbonate, which may forms the carbonate cyclic (Thébault et al. 2015;
Panchgalle et al. 2015). This study aimed to carry these modifications in order to
link the methods from both Benyahya et al. (2013) and Thébault et al. (2014) to
modify the catechin for the synthesis of polyurethane. The chemical modification

2
involved four steps: the glycidylation of catechin, the opening of epoxide, the
carbonate synthesis which was conducted in order to obtain carbonate cyclic from
the diol; and then the condensation of amine on this cyclic carbonate. This last
step has been tested in this study by condensation of simple amine. In the future,
if the synthesis of polyurethane has been successfully done, this technic can be
develop in order to find the non biocidal alternative in the field of wood
preservation.
Meanwhile as a wood preservative, studies conducted by Harun and
Labosky (2007); Kawamura et al. (2010); and Vek et al. (2013) reported that catechin can be applied in the field of wood preservation due to its antimicrobial and
antifungal properties. Moreover, this type of flavonoid is also proven as a valuable
biomarker of wood decay (Mounguengui et al. 2007). The chemistry of flavonoids is dominated by the presence of multiple phenol groups which furthermore
give them strong complexing abilities and antioxidant properties. Their antifungal
trait can be explained by the process of depolymerization of wood
macromolecules that can be initiated by free radicals which is involving many
oxidation process. In contrary, fungicidal action, free radical scavenging/ antioxidant, and metal chelating, as the properties of phenols can effectively protect the
wood (Malterud et al. 1985; Schultz et al. 2008).
In the field of wood preservation, it is unlikely to find a single compound
or natural antifungal to inhibit the various biological agents capable of colonizing
wood and wood products. Previous study by Malterud et al. (1985) also reported
that the effect of flavonoids on rot-producing fungi, particularly the catechin
compound, is selective (active against only one of the fungi tested). In this context,
it would be seen necessary to selectively changing its properties, for example
through chemical modification, in order to increase the range of potential utility.
Modification with compounds such as fatty acids, for example, through esterification or formation of an ester linkage (Figure 1) could be interesting to study.
OH
O

HO

O

(CH2)nCH3

O

OH
OH

Figure 1 Chemical modification of catechin through grafting with link ester.
Clausen et al. (2010) stated that the fatty acid chain could give the hydrophobic properties in order to increase the resistance to leaching. In the previous
study conducted by Coleman et al. (2010) and Pohl et al. (2011), they reported

3
that low molecular weight, aliphatic fatty acids such as pentanoic (C5) to decanoic
acids (C10) are highly effective against a wide range of fungal pathogens. These
compounds have the potential to be used as environmentally friendly antifungal
agents. Moreover, other study had been conducted in order to develop fungicide
formulation through the combination of low molecular weight fatty acids with selected adjuvants such as organic acids or other natural compounds with more recent work applied to wood preservation (Clausen et al. 2010).
Beech wood (Fagus sylvatica L.) is one of the commercially most important tree species in Europe that has been widely used in the furniture, plywood,
particleboard, and bentwood industry (Gryc et al. 2008). Its natural durability is
low (class 5) with high permeability and a low dimensional stability properties
according to EN 350-2 standard (1994). According to its properties, this wood is
also suitable for impregnation treatment due to its high treatability. The aim of
this study was to chemically modify the catechin’s hydroxy groups with the fatty
acid chains and to investigate the possibility of its utilization in wood preservation.
Different parameters such as weight percent gain after impregnation, resistance to
leaching, percentage of leaching, and decay resistance to the white rot fungus
Coriolus versicolor were investigated to evaluate the efficacy of the modified catechin as a wood preservative.
Formulation
Catechin is one of the naturally-occurred polyphenols possessing powerful
scavanger related to its antioxidant trait (Aditya et al. 2015; Gadkari and Balaraman 2015). By selectively changing its properties through chemical modification,
for example through uretahane synthesis with epoxy resin and through
esterification with several fatty acids, the range of its potential utility will increase.
Several studies have been conducted in modifying polyphenols compound both as
a main compound in the synthesis of isocyanate-free polyurethane and as a wood
preservative (Malterud et al. 1985; Laks et al. 1988; Thébault et al. 2014;
Thébault et al. 2015). However, only a few of them have focused on the catechin
modification. Therefore, the questions that need to be asked: what is the best
method in syntesyzing catechin with epoxy resin to form urethane or polyurethane
without using isocyanate? How about the fatty acids in the context of wood
preservation? How would the resulted products’characteristics impact the wood
properties, particularly to their resistance of leachability and against fungi? How
much of those impacts are significant?
Objective
The first objective of this study is to chemically modify catechin in order
to synthesize the urethane for developing non-isocyanate-based polyurethanes
(NIPUs). Meanwhile, the second objective of this study is to chemically modify
the catechin’s hydroxy groups with the fatty acid chains in the context of its
potential utilization as a wood preservative.

4
Benefits
The study is expected to provide scientific informations, original data, and
statistical analysis on the methods of modifying the catechin’s hydroxy groups
and its derived products. Further, the results of this study could become a
reference on the methods and providing supporting data for the future study in the
field of polyphenols modification and its application, particularly in the making of
isocyanate-free polyurethane and in the development of natural wood preservative.

2 MATERIALS AND METHODS
Location and Period of Research
This study was conducted at the Laboratory of Wood Material Research
and Study (Laboratoire d’Etudes et de Recherche sur le Matériau Bois) in Nancy,
France from February to July 2016.
Tools and Materials
(+)-Catechin hydrate, epichlorohydrin (99.0%), benzyltriethylammonium
chloride (≥98.0%), sodium hydroxide (≥98.0%), potassium carbonate (K2CO3),
butylamine, capric acid, myristic acid, lauric acid, and all reactants were obtained
from Sigma–Aldrich Chimie, France.
Synthesis Procedures
Reaction of Catechin and Epoxide
Procedure of glycidilation of catechin
A 100-mL two-necked flask equipped with a condenser, a septum cap, and
a magnetic stirring bar was charged with 1 g of catechin (3.445 mmol). Catechin
was mixed in epichlorohydrin (5 Mequiv./OH), heated under a reflux condenser at
100°C, then benzyltriethylammonium chloride (0.05Mequiv./substrate) was added.
After one hour, the resulting solution was cooled down to 30°C and an aqueous
solution of NaOH 20 wt% (2 Mequiv./OH) with 0.05 Mequiv. of phase transfer
catalyst (BnEt3NCl) was added drop by drop to prevent a massive precipitation of
the reaction mixture. The mixture was stirred vigourously for 90 minutes. The
organic layer was separated, dried over MgSO4, and vacuum-concentrated.
Procedure of hydrolysis of epoxide (C27H30O10) in hot water
In a 100-mL round-bottom flask equipped with a condenser, C27H30O10
(1.03 g, 2 mmol) was added to 12 mL of distilled water; then, 6 mL of
tetrahydrofuran (THF) was added. The solution was stirred at the temperature of
80°C and monitored using thin-layer chromatography (TLC). Generally, by
increasing the heating temperature to T=80°C, the reaction of water, C27H30O10,
and THF mixed well. The reaction was then monitored by TLC and completed
after 16 hours. After completion, the mixture was concentrated in a rotary evapo-

5
rator to remove the organic solvent (THF). The remaining water was then
removed using a freeze dryer.
Procedure of carbonate synthesis from the diol derivative (C27H38O14)
In a 100-mL three-neck flask fitted with a condenser and a CaCl2 guard
tube, C27H38O14 was stirred with 24 eq. of dimethyl carbonate (3.64 mL, 43.18
mmol) and 0.03 eq. of potassium carbonate (K2CO3) (0.07 g, 0.054 mmol). The
mixture was then refluxed at T=80°C for 24 hours. The excess of dimethyl
carbonate was then concentrated under reduced pressure.
Procedure of one-pot carbamate synthesis from C31H30O18
In a 100-mL three-neck flask fitted with a condenser and a CaCl2 guard
tube, butyl amine and C31H30O18 were stirred, and then 5 to10 mL methanol was
added to lower the viscosity of the reaction mixture. The reaction medium was
subsequently, vigorously stirred using magnetic stirring and heated at 80°C for 8
hours. After completion, methanol was removed using a rotary evaporator. The
progress of the reaction was monitored by Fourier transform infrared (FTIR)
analysis. The reaction mixture was then extracted using 150 mL of ethyl acetate;
this organic phase was then washed with 2×35 mL of HCl 1N and 35 mL of a
saturated NaCl solution before being dried over using MgSO4, filtered and then
concentrated under reduced pressure.
Nuclear Magnetic Resonance (NMR) analysis
The products were identified using NMR performed on a Bruker AC-200
MHz and 400 MHz. All samples were dissolved either in methanol-d4 or in
chloroform-d or in DMSO-d6 for 1H NMR analysis. Chemical shifts were
expressed in parts per million (ppm) with reference to the solvent peak.
Fourier Transform Infrared (FTIR) analysis
FTIR spectra were recorded on a Perkin Elmer Spectrum One FT-IR
Spectrometer with transmittance mode. The spectra were obtained by 4
scans/analysis, 4 cm-1 resolution, data intervals of 1 cm-1, and 0.2 cm/s sweeping
speed. Start scan from 4000 cm-1, end scan 650 cm-1. Double beam method was
used.
Grafting of Catechin and Fatty Acid
Procedure for reaction of catechin and capric acid (C10)
A 100-mL two-necked flask equipped with a condenser, a septum cap and
a magnetic stirring bar was charged with 1 g of catechin. Catechin, capric acid 1.5
eq., and N,N'-Dicyclohexylcarbodiimide (DCCI) 1.5 eq. were dissolved in acetonitrile. The reaction was carried out with agitation at ambient temperature for 5
hours. Product was then extracted with ethyl acetate, then washed with a saturated
NaHCO3 solution, a saturated NaCl solution, and then dried over MgSO4. After
completion, the products were separated using column chromatography (acetate
ethyl:hexane/50:50).

6
Procedure for reaction of catechin and myristic acid (C14)
A 100-mL two-necked flask equipped with a condenser, a septum cap and
a magnetic stirring bar was charged with 1 g of catechin. Catechin, myristic acid
1.5 eq., and DCCI 1.5 eq. were dissolved in acetonitrile. The reaction was carried
out with agitation at ambient temperature for 5 hours. The product was then
washed with ethyl acetate, a saturated NaHCO3 solution, a saturated NaCl solution,
and then dried over MgSO4. After completion, the products were separated using
column chromatography (acetate ethyl:hexane/50:50).
Procedure for reaction of catechin and lauric acid (C12)
Catechin, lauric acid 1 eq., and DCCI 1 eq. were dissolved in acetonitrile.
The reaction was carried out in an ice bath with magnetic stirring during 20
minutes. Soon after, the ice was removed, and the reaction was continued under
ambient temperature during 48 hours under N2 condition. After completion, quick
filtration under vacuum was conducted and produced yellow solid after evaporation. The product was then washed with ethyl acetate, a saturated NH4Cl solution,
a saturated NaHCO3 solution, a saturated NaCl solution, and then dried over
MgSO4. The solution then concentrated under reduced pressure and purified using
column chromatography (cyclohexane:ethyl acetat/8:2).
Spectroscopic characteristics
The resulting products were identified using Nuclear Magnetic Resonance
(NMR) both 1H NMR and 13C NMR, performed on a Bruker AC-200 MHz and
400 MHz; and Fourier Transform Infrared FTIR spectra which were recorded on a
Perkin Elmer Spectrum One FT-IR Spectrometer.
Wood Treatment and Measurement
Sample preparation
Ninety-six of wood specimens from beech wood (Fagus sylvatica L.) were
cut into dimensions of 2.5 cm × 1.5 cm × 0.5 cm (L × R × T). 64 specimens were
used for wood treatment, and 31 specimens were used as a control in the decay
fungi test. All of the wood specimens were oven dried at 103±2°C for 48 hours
(m0).
Wood impregnation
Wood specimens of 2.5 cm × 1.5 cm × 0.5 cm were oven-dried at
103±2°C for 48 hours and weighed (m0). Dried wood specimens (16 specimens
per treatment) were placed in a 250 mL beaker inside a desiccator equipped with a
two-way tap and subjected to a 90-110 mbar vacuum for one hour. Wood specimens were then impregnated with 5% concentration of all treatments (catechin
and modified catechin) in the ethanol solution (Figure 2). Afterwards, all specimens were oven-dried at 103±2°C for 24 hours until their mass were stable (m1).

7
Vacuum hose

Input hose for the
impregnation solution
Desiccator
Impregnation solution
Wood specimens

Figure 2 Illustration of vacuum impregnation of the wood specimens using desiccator
Weight percent gain
After their mass were stable, all wood specimens were then weighed (m1)
and their weight percentage gain (WPG) were calculated following this equation:
WPG (%) = (m1-m0)/m0 ×100

(equation 1)

where:
WPG = weight percent gain of the wood specimen after the impregnation
m0
= initial oven-dried weight wood specimen before the impregnation
m1
= oven-dried weight of wood specimen after the impregnation
Leachability
Leaching process was evaluated according to the European standard ENV
1250-2 (1994). Eight wood specimens from each treatment methods were
immersed in 90 mL distilled water and subjected to six leaching periods of
increasing duration under continous shaking at 20°C (Figure 3). In the first period,
the specimens were shaken for 1, 2, and 4 hours, and in each periods, the water
were replaced. Afterwards, the specimens were removed and kept without water
for 16 hours. Leaching process was then continued to the next periods for 8, 16,
and 48 hours. After all the leaching periods completed, all the wood specimens
were oven dried at 103±2°C for about 24 hours and their mass were measured
(m2). Weight percentage gain after leaching (WPAL) and percentage of mass loss
after leaching (PL) were calculated following this equation:
WPAL (%) = (m2 – m0)/m0 × 100

(equation 2)

PL (%) = (m1 – m2)/m1 × 100

(equation 3)

where:
WPAL = weight percentage gain after leaching
PL
= mass loss percentage of the wood specimen after leaching
= initial oven-dried weight of the wood specimen before the impregnation
m0

8
m1
m2

= oven-dried weight of the wood specimen after the impregnation
= oven-dried weight of wood specimen after leaching

Bottle filled with water
and wood specimens
Shaker

Speed setting

Figure 3 Leaching process under continuous shaking method based on ENV 12502
Decay measurement
Untreated and treated wood specimens were exposed to the white rot fungus C. versicolor according to the EN 113 standard (1986). Sterile culture medium (20 mL), prepared from malt (25 g) and agar (40 g) in distilled water (1.0 L),
were placed in a 9 cm petri dish, inoculated with fungus and cultivated in an incubator at 22±2°C of temperature and 70±5% of relative humidity for approximately
15 days to allow the colonization of the petri dish surfaces by the mycelium. After
being sterilized at the temperature of 110°C for 20 min, all wood specimens including untreated wood as a control and wood specimens before and after leaching were put in the petri dish and incubated for 12 weeks. After this period, mycelia were cleaned from the wood specimen and then oven dried at 103±2°C for 24
hours and weighed. Decay resistance was measured by the weight loss due to the
fungal attack according to the following equation:
WL (%) = (ma – mb)/ma × 100

(equation 4)

where:
WL = percentage of weight loss
ma
= dried weight of the wood specimen before being exposed to fungi
mb
= dried weight of the wood specimen after being exposed to fungi
After obtaining the percentage of weight loss, durability class (DC) of
each treatment then calculated and classified based on their durability index ―x‖
(Table 1) according to EN 350-1 (1994).

9
Table 1 Classes of natural durability of wood to fungal attack using laboratory test
based on EN 113
Durability class (DC)
Description
Results expressed in X* value
1
Very durable
x ≤ 0.15
2
Durable
x > 0.15 but ≤ 0.30
3
Moderately durable
x > 0.30 but ≤ 0.60
4
Slightly durable
x > 0.60 but ≤ 0.90
5
Not durable
x > 0.90
*x is the durability index expressed as weight loss of the test specimens / weight loss of the
reference specimens.

Data Analyzing
T-test analysis was used to compare the data from each specimens and
treatments. The data were analyzed in order to see their groupings. The analysis
was conducted using Microsoft Excel, R, and Rstudio v0.99.902 – © RStudio, Inc.

10

3 RESULTS AND DISCUSSIONS
Reaction of Catechin and Epoxide
Glycidilation of Catechin
The glycidylation of catechin was conducted following the experimental
procedure in the presence of phase transfer catalyst (Benyahya et al. 2014). It was
described that catechin was initially reacted with epichlorohydrin (5
Mequiv./phenolic OH) in the presence of benzyltriethylammonium chloride
(BnEt3NCl) as a phase transfer catalyst. Afterwards, the reaction mixture
underwent an alkaline treatment, NaOH (27.6 mmol, 1.105 g) at 30°C without
removing the epichlorohydrin (Figure 4). The raw yield after extraction is 74%.

Figure 4 Reaction of catechin and epichlorohydrin
To determine the chemical structure of the tetraglycidil derivative
(C27H30O10), which is corresponding to the colorless oil product, NMR analysis
was conducted. Figure 5 presents the NMR spectrum of catechin meanwhile
Figure 6 presents the NMR spectrum after glycidilation of catechin. Aliphatic
signals arising from methyl oxirane groups were identified.

Figure 5 1H NMR spectrum of catechin

Figure 6 1H NMR spectrum after glycidylation of catechin

11
Indeed Ha protons appeared to overlap with H4 protons belonging to the
flavonoid skeleton as a multiplet between 2.75 and 2.95 ppm. The multiplet between 3.20 and 3.40 ppm corresponded to Hb protons. The two signals at 3.68–
3.85 ppm and 4.05–4.35 ppm both corresponded to Hc protons. The methylene
and methyne ring proton signals appeared in the 2.73–4.65 ppm range and the
CH2-O protons gave resonances signals in the 3.92–4.65 ppm spectral range.The
chemical modification of the catechin structure also influenced the H6 and H8 signals that almost merge with each other around 6.03 ppm.
Figure 7 shows the evidence of epoxide formation at 908.5 cm-1 presented
by FTIR measurements. This peak is assignable to the vibration of epoxy groups.
The comparison between before and after glycidilation can also be seen here
which the intensity of the stretching vibration bands of alcohol (phenol) groups in
the 3000—3500 cm-1 area differ. In the (tetra)glycidylated product, a drastic
decrease was observed from this band, showing that the OH phenol groups have
been successfully substituted.

3459.2
(OH phenol groups)

908.48
(epoxide)

Figure 7 FTIR transmission spectrum after glycidilation of catechin
Hydrolysis of Epoxide in Hot Water
Hydrolysis of epoxide was conducted by heating the crude product in hot
water at a temperature between 60 and 80°C for 16 hours, in order to open the
epoxide ring (Figure 8). Wang et al. (2008) reported that the ring opening
reactions of epoxides can be promoted using hot water with a good yield. It was
proposed that the hot water acts as a modest acid catalyst. In this study, THF was
added to the mixture to increase the solubility in the water. The final product from
this reaction corresponded to a colorless oil product.

Figure 8 Hydrolysis of epoxide

12
Figure 9 shows the results from FTIR analysis by showing the epoxide
(C27H30O10) and the diol (C27H30O14) spectra. From this analysis, it can be clearly
seen that the spectrum of C27H30O14 was increased, which marked the opening of
the epoxide ring.

(diol)
908.22

3347.7

908.22
(epoxide)

Figure 9 FTIR transmission spectrum: comparison between epoxide and diol
To confirm the chemical structure of the diol derivative (C27H38O14), NMR
analysis was conducted (Figure 10). Protons of the original methyl oxirane groups
were more or less shifted with diol formation. Indeed, Ha and Hc protons were
gathered as a multiplet between 3.35 and 3.75 ppm. The multiplet between 3.75
and 4.05 ppm corresponds to Hb protons. It is noticeable that Ha and Hb protons
are drastically shifted towards the downfield region (by 0.6 to 1 ppm for Ha and
0.55 to 0.85 ppm for Hb, respectively). The influence on the H6 and H8 signals this
time were opposite because they split to 6.03 ppm and 6.10 ppm.

Figure 10 1H NMR spectrum after epoxide opening reaction (C27H38O14)

13
Carbonate Synthesis
Latest studies reported that carbonation can be implemented from reaction
with dimethyl carbonate (Panchgalle et al. 2011, Thébault et al. 2015). Carbonate
synthesis was conducted in order to obtain carbonate cyclic (C31H30O18), which
afterwards, could be reacted with amines to provide carbamate function. The
reaction with dimethyl carbonate can be seen in Figure 11 which was carried out
by heating at 80°C for 24 hours. Dimethyl carbonate was used here both as a
solvent and as a reagent, but because its solvating properties proved to be poor in
this case, the amount of dimethyl carbonate was increased up to 24 eq.

Figure 11 Synthesis of cyclic carbonate derivatives (C31H30O18)
The expected product after carbonation shows up typically at 1797 to 1800
cm-1 on infrared spectra. According to the infrared analysis presented in Figure 12,
it can be seen that the carbonate cyclic formation was marked by the signal that
appeared at 1793 cm-1. The decrease of the alcohol wide band at 3000 to 3500 cm1
shows that the diol moieties reacted well. The signal at 1748.5 cm-1 may be due
to some residual (or excess) of the dimethyl carbonate. The total raw yield after
carbonation was 69%.

3445.6
Phenol
O-H
stretch
Carbonate cyclic
C=O
stretch 1792.7

1748.5
Carbonate non cyclic
O-H
stretch

Figure 12 FTIR transmission spectrum after carbonation

14
To confirm the chemical structure of the cyclic carbonate derivative
(C31H30O18), NMR analysis was conducted. Figure 13 presents the NMR spectrum.
Protons of the original glycerol part are being significantly shifted dowfield with
cyclic carbonate formation. Indeed, C=O moiety introduction deshields the
neighboring protons Ha, Hb and Hc by 0.75–1 ppm. The rest of the signals
referring to the flavonoid block is very little affected by the carbonate function
insertion.

Figure 13 1H NMR spectrum after carbonation reaction (C31H30O18)
Carbamate Synthesis
In this study, butylamine was used as the first model of amination. The
reaction was carried out by heating the previous product (C31H30O18) with 10 eq.
of butylamine with the addition of 10 mL methanol. The mixtures were reacted at
80°C for 16 hours (Figure 14).

Figure 14 Synthesis of carbamate with butylamine
To confirm the presence of a urethane structure, the product was examined
using FTIR measurement, which resulted in the appearance of a high peak
corresponding to the carbamate group (1696.5 cm-1) (Figure 15). In the previous
study conducted by Thébault et al. (2015), major bands at 1690 cm-1 (C=O double
bond of amides) clearly indicated the presence of urethane bonds.

15

Carbamate
C-O
Stretch
1710

3330.7
Phenol

O-H
Stretch

Carbamate

C-O
Stretch

1696.5

Figure 15 Comparison between carbamation followed and unfollowed by a
liquid/liquid extraction step
Measurements using 1H NMR were difficult to read because complicated
signals appeared because of the presence of impurities in the sample (Figure 16).
Primarily, residual butyl amine obscured aliphatic signals of the formed urethane
derivatives as well as the H4 signal. However, the best evidence for carbamation is
the appearance at 3.1 ppm of a signal characteristic of CH2 (D of carbamate, significantly deshielded compared with the amine residual CH2 (D) at 2.68 ppm, because of the proximity of the newly attached -(CO)O group forming the carbamate
bond.

Figure 16 1H NMR spectrum after carbamation reaction with butyl amine
(C47H74N4O18)

16
Grafting of Catechin and Fatty Acid
In this study, hydroxyl groups of catechin were esterified with the fatty
acids. Grafting of catechin and fatty acids was conducted by reacting catechin
with capric acid, myristic acid, and lauric acid respectively. Spectroscopic
characteristics of each products are presented for each synthesis, including the
monoester and diester products (Figure 17 – Figure 23).
OH

3'
2'
8

HO

O

7

2

OH

4'
5'

1'
6'
3

6
5

OH

4

OH

Figure 17 Catechin
Catechin: 1H NMR (DMSO-d6, 400MHz): d(ppm) : 2,30 (dd, 1H, J = 8,1 Hz, J
=16,1 Hz, 4ax) ; 2,67 (dd, 1H, J = 5,4 Hz, J = 16,1 Hz, 4eq) ; 3,87 (ddd, 1H, J =
5,7 Hz, J = 7,8 Hz, J = 7,5 Hz, 3) ; 4,49 (d, 1H, J = 7,5 Hz, 2) ; 4.86 (s, 1H, OH 3);
5,7 (d, 1H, J = 2,4 Hz, 6) ; 5,9 (d, 1H, J = 2,2 Hz, 8) ; 6,6 (dd, 1H, J = 2.1 Hz, J =
8,37 Hz, 6’) ; 6,69 (d, 1H, J = 7.6 Hz, 5’) ; 6,73 (d, 1H, J = 1,8 Hz, 2’) ; 8.84 (s,
1H, OH3’) ; 8.86 (s, 1H, OH4’) ; 8.95 (s, 1H, OH5) ; 9.18 (s, 1H, OH7); 13C NMR
(DMSO-d6, 400MHZ): d(ppm): 80.94 (C2); 66,26 (C3); 28 (C4); 156.40 (C5);
95.05 (C6); 156.12 (C7) ; 93.80 (C8) ; 155.31 (C9) ; 99.01 (C10) ; 130.54 (C1’) ;
114.45 (C2’) ; 144.79 (C3’) ; 144.79 (C4’) ; 115.2 (C5’) ; 118.6 (C6’)
OH

e

g
O

c

d
f

HO

O

a
b

O

OH
OH

Figure 18 Catechin modified with capric acid (monoester)
Catechin-C10 (monoester): 1H NMR (DMSO-d6, 400MHz): d(ppm) : 0.9 (t,
3H, He); 1.29 (m, 12H, Hd); 1.6 (q, 2H, Hc), 2.54 (t, 2H, Hb); 2,35 (dd, 1H, J = 8,6
Hz, J =15.76 Hz, 4ax) ; 2,98 (dd, 1H, J = 5,44 Hz, J = 16,00 Hz, 4eq) ; 4.04
(ddd, 1H, J = 5,7 Hz, J = 7,38 Hz, J = 3.36 Hz, 3) ; 4,13 (d, 1H, J = 5.14 Hz, 2);
4.64 (s, 1H, OH3); 5,9 (d, 1H, J = 2,35 Hz, 6) ; 5,9 (d, 1H, J = 2,14 Hz, 8) ; 6,6

17
(dd, 1H, J = 1.9 Hz, J = 8,37 Hz, 6’) ; 6,69 (d, 1H, J = 8 Hz, 5’) ; 6,73 (d, 1H, J =
1,9 Hz, 2’); 8.85 (s, 1H, OH4’) ; 8.95 (s, 1H, OH5) ; 9.18 (s, 1H, OH7); 13C NMR
(DMSO-d6, 400MHZ): d(ppm): 14.6(Ca); 22.7 (Cb); 25 (Cf); 29.1 (Ce,4); 31.8
(Cc); 33.8 (Cg); 66.3 (C3); 80.7 (C2); 93.9 (C8); 95.4 (C6); 98.9 (C10); 115.9 (C2’);
125.7 (C5’); 122.2 (C6’); 130.6 (C1’); 138.1 (C3’); 148.7 (C4’); 155.3 (C5); 156.14
(C9); 156.5 (C7) 171.2 (Cd); IR: 1736 cm-1 (O-CO), 2853-2923 cm-1 (aliphatic
chain), 3344 cm-1 OH phenolic; Tm: 80-90 °C
O

e
f

d

O

b

g

c
g'

O

a
c'

d'

a'

f'
HO

O

b'

e'

O

OH
OH

Figure 19 Catechin modified with capric acid (diester)
Catechin-C10 (diester): 1H NMR (CdCl3, 400MHz): d(ppm) : 0.86 (t,
3H,J=6Hz, Ha,a’); 1.27 (m, 24H, Hb,b’,c,c’e,e’); 1.6 (q, 2H, J=7, Hf,f’), 2.54 (t,
2H,J=7.3Hz, Hg,g’); 2,4 (dd, 1H, J = 8,8 Hz, J =16.18 Hz, 4ax) ; 2,77 (dd, 1H, J =
5,6 Hz, J = 16,18 Hz, 4eq) ; 3.87 (ddd, 1H, 3) ; 4.66 (d, 1H, J = 8 Hz, 2); 5.1 (s,
1H, OH3); 5,75 (d, 1H, J = 2,19 Hz, 6) ; 5,94 (d, 1H, 8) ; 7.2 (dd, 1H, 6’) ; 7.25 (d,
1H , 5’) ; 7.31 (d, 1H, 2’); 9.01 (s, 1H, OH5) ; 9.27 (s, 1H, OH7); 13C NMR
(CDCl3, 400MHZ): d(ppm): 14.4 (Ca,a’); 22.7 (Cb,b’); 25 (Cf,f’); 29.1 (Ce,e’,4); 32
(Cc,c’); 34 (Cg,g’); 66.9 (C3); 80.8 (C2); 94.3 (C8); 96.1 (C6); 99.6 (C10); 123 (C2’);
123.7 (C5’); 126.1 (C6’); 138.9 (C1’); 142 (C3’,4’); 155.5 (C5); 156.69 (C9); 157.09
(C7); 171.1(Cd,d’).
OH

e

g
O

c

d
f

HO

O

a
b

O

OH
OH

Figure 20 Catechin modified with myristic acid (monoester)
Catechin-C14 (monoester): 1H NMR (DMSO-d6, 400MHz): d(ppm) : 0.86 (t,
3H, J= 7Hz, Ha); 1.24 (m, 20H, Hb,c,e); 1.62 (q, 2H,J=7 Hz, J=14.14Hz, Hf),
2.54 (t, 2H, Hg); 2,38 (dd, 1H, J = 9Hz, J =17 Hz, 4ax) ; 2,7 (dd, 1H, J = 5,4 Hz,
J = 17,00 Hz, 4eq) ; 3.84 (ddd, 1H, 3) ; 4,56 (d, 1H, J = 7.4 Hz, 2); 5 (s, 1H,
OH3); 5,9 (d, 1H, 6) ; 5,7 (d, 1H, 8) ; 6,7 (dd, 1H, 6’) ; 6,7 (d, 1H, 5’) ; 6,73 (d,

18
1H, 2’); 8.97 (s, 1H, OH4’) ; 9.22 (s, 1H, OH5) ; 9.61 (s, 1H, OH7); 13C NMR
(DMSO-d6, 400MHZ): d(ppm): 14 (Ca); 22 (Cb); 24.5(Cf); 28.8 (Ce,4); 31.3
(Cc); 33.3 (Cg); 68.3 (C3); 82.3 (C2); 95.5(C8); 96.5 (C6); 100 (C10); 117.1 (C2’);
119.6 (C5’); 123.5 (C6’);132.3 (C1’), 141(C3’); 149.6 (C4’) ; 156.7 (C5); 157.2
(C9); 157.8 (C7) 172.1(Cd); IR: 1736 cm-1 (O-CO), 2852-2922 cm-1 (aliphatic
chain), 3367 cm-1 OH phenolic; Tm: 130-140 C°
O

e'
f'

O

d'

b'
c'

g'

a'

g
O

c

d
f

HO

O

b

e

O

a

OH
OH

Figure 21 Catechin modified with myristic acid (diester)
Catechin-C14 (diester): 1H NMR (CDCl3, 400MHz): d(ppm) : 0.85 (t, 6H,J=
6.3Hz, Ha); 1.26 (m, 40H, He,c,b); 1.62 (q, 4H,J=6.4 Hz, J=14.7Hz, Hf,f’), 2.54 (t,
4H, Hg, g’); 2,4 (dd, 1H, J = 8,9Hz, J=16.22Hz, 4ax) ; 2,78 (dd, 1H, J = 5,4 Hz, J
= 16.22 Hz, 4eq) ; 3.86 (ddd, 1H, J= 6.24Hz, J= 14.21, 3) ; 4,65 (d, 1H, J = 8.16
Hz, 2); 5.12 (d, 1H, J= 5 Hz, OH3); 5,94 (d, 1H, 6) ; 5,74 (d, 1H, 8) ; 7.27 (dd,
1H, 6’) ; 7.25 (d, 1H, 5’) ; 7.31(d, 1H, 2’); 8.9 (s, 1H, OH5) ; 9.25 (s, 1H, OH7);
13
C NMR (CDCl3, 400MHZ): d(ppm): 13.9 (Ca,a’); 22.3 (Cb,b’); 24.6 (Cf,f’); 28.9
(Ce,e’,4); 31.4(Cc,c’); 33.7 (Cg,g’); 66.4 (C3); 80.1 (C2); 93.8 (C8); 95.5 (C6); 99.1
(C10); 122.3 (C2’); 123.2 (C5’); 125.5 (C6’); 138.6 (C1’); 141.3 (C3’) 141.5 (C4’);
154.9 (C5); 156.1(C9); 156.5 (C7) ; 170.4(Cd,d’).
OH

e

g
O

c

d
f

HO

O

a
b

O

OH
OH

Figure 22 Catechin modified with lauric acid (monoester)
Catechin-C12 (monoester): 1H NMR (DMSO-d6, 400MHz): d(ppm) : 0.86 (t,
3H, Ha); 1.27 (m, 16H, Hb,c,e); 1.63 (q, 2H,J=7.5 Hz, J=15Hz, Hf), 2.54 (t,
2H,J=7.3Hz, Hg); 2,37 (dd, 1H, J = 8,4 Hz, J =19 Hz, 4ax) ; 2,7 (dd, 1H, J = 5,6
Hz, J = 17,00 Hz, 4eq) ; 3.84 (ddd, 1H, 3) ; 4,56 (d, 1H, J = 7.6 Hz, 2); 5 (s, 1H,
OH3); 5,9 (d, 1H, J = 2,3 Hz, 6) ; 5,7 (d, 1H, J = 2,3 Hz, 8) ; 6,6 (dd, 1H, J = 2 Hz,
J = 8,2 Hz, 6’) ; 6,7 (d, 1H, 5’) ; 6,73 (d, 1H, J = 2.1 Hz,J=8.2 Hz, 2’); 8.97 (s, 1H,
OH4’) ; 9.22 (s, 1H, OH5) ; 9.61 (s, 1H, OH7); 13C NMR (DMSO-d6, 400MHZ):

19
d(ppm): 14 (Ca); 22 (Cb); 24. (Cf); 28.6 (Ce,4); 31.4 (CC); 33.1 (Cg); 66.3 (C3);
80.6 (C2); 93.8 (C8); 95.4 (C6); 98.9 (C10); 115.9 (C2’); 122.2 (C5’); 125.5
(C6’);130.7 (C1’), 141(C3’); 148.6 (C4’) 155 (C5); 156.18 (C9); 156.5 (C7) 171.6
(Cd); IR: 1736 cm-1 (O-CO), 2853-2922 cm-1 (aliphatic chain), 3365 cm-1 OH
phenolic; Tm: 100 -110 C°
O

e
f

O

d

b
a

g

c
g'

O

d'
c'

f'
HO

O

O

e'

a'
b'

OH
OH

Figure 23 Catechin modified with lauric acid (diester)
Catechin-C12 (diester): 1H NMR (CDCl3, 400MHz): d(ppm) : 0.85 (t, 6H,J=
7Hz, Ha); 1.26 (m, 32H, He,c,b); 1.62 (q, 4H,J=7.18Hz, J=14.65Hz, Hf,f’), 2.54 (t,
4H, Hg, g’); 2,41 (dd, 1H, J = 8,8Hz, J=16.21Hz, 4ax) ; 2,78 (dd, 1H, J = 5,7 Hz, J
= 16.12 Hz, 4eq) ; 3.84 (ddd, 1H, J=5.3Hz, J=6.8, 3) ; 4,66 (d, 1H, J = 8.2 Hz,
2); 5.14 (d, 1H, J= 5.4 Hz, OH3); 5,94 (d, 1H, J = 2,11 Hz, 6) ; 5,74 (d, 1H, J =
2,17 Hz, 8) ; 7.23 (dd, 1H, J = 1.5 Hz, J = 6.54 Hz, 6’) ; 7.25 (d, 1H, 5’) ; 7.31(d,
1H, J = 2.2 Hz, 2’); 9 (s, 1H, OH5) ; 9.26 (s, 1H, OH7); 13C NMR (CDCl3,
400MHZ): d(ppm): 13.9 (Ca,a’); 22.1 (Cb,b’); 25 (Cf,f’); 28.6 (Ce,e’); 31.4(Cc,c’);
33.2 (Cg,g’); 66.4 (C3); 80.2 (C2); 93.9 (C8); 95.5 (C6); 98.9 (C10); 122.3 (C2’); 123
(C5’); 125.7 (C6’); 138.4 (C1’); 141.6 (C3’,4’); 154.9 (C5); 156.1(C9); 156.5 (C7) ;
170.4(Cd,d’).
The reaction of catechin and capric acid was conducted by mixing catechin
and capric acid in acetonitrile with the presence of DCCI. The reaction was
conducted at ambient temperature with a magnetic stirrer during 5 hours. The
resulting product was obtained by purification presenting 70% yield with solid
form. The reaction between catechin and myristic acid was conducted as the same
procedure with reaction catechin and capric acid, meanwhile reaction between
catechin and lauric acid 1 eq., and DCCI 1 eq. were dissolved in acetonitrile and
were carried out under a freezing condition with magnetic stirring during 20
minutes.
Modification of hydrophilic compounds such as catechin with hydrophobic
compounds, including fatty acids, can result in products with an amphiphilic
behavior. This trait will possess both hydrophilic and hydrophobic properties.
This amphiphilic properties enable the hydrophobic part to control the release
rate; in this case, it is believed that, inside the wood, these molecules would
effectively control the release of the product while at the same time, the
hydrophilic part form a stable suspension in water (Salma et al. 2010; Ding et al.
2011). A further study conducted by Fray et al. (2013) stated that amphiphilic

20
derivatives are able to self-assemble in the modification of chitosan chains (which
are hydrophilic) with hydrophobic compounds.
The results corresponding to the yield of catechin modified with fatty acids
are presented in Table 2. Generally, every treatment produces good yields,
ranging from 65 to 70% of the monoester. The addition of C14 brought the
highest yield, which produced 70% yield of the monoester and 8% of the diester.
Monoester is formed when one molecule of acid has been added to the catechin
while diester is formed when two of molecules of acid have been added instead of
only one. The formation of diester is a secondary product, so it has a low yield
which has no significance because the objective of adding them is to make the
catechin as hydrophobic as it can be.
Table 2 Yield of catechin modified with fatty acids
Yield (%)

Treatment
Catechin-C10
Catechin-C12
Catechin-C14

Monoester
70
70
65

Diester
5
8
5.82

Application as a Wood Preservative
WPG, WPAL, PL measurements
To understand their effects on wood in the context of its application for
wood preservation, the wood specimens were impregnated with 5% of catechin
and catechin modified with fatty acid in ethanol solution (w/w). The percentage o