epoxidation of wild safflower (carthamus oxyacantha) - Research ...

International Journal of ChemTech Research 

CODEN( USA): IJCRGG ISSN : 0974-4290 

Vol. 3, No.3, pp 1152-1163, July-Sept 2011 

Epoxidation of Wild Safflower (Carthamus 

oxyacantha) Oil with Peroxy acid in presence 

of strongly Acidic Cation Exchange Resin IR- 

122 as Catalyst 

Pawan D. Meshram*, Ravindra G. Puri, Harshal V. Patil 

Department of Chemical Technology, North Maharashtra University, Jalgaon, 

Maharashtra - 425 001, India; 

Tel: +91-0257-2257144; Fax: +91-0257-2258403, 2258406 

*Corres.author: pawan.dm@gmail.com 

Abstract: Epoxidation brings out the transformations at the unsaturated part of oil molecule to introduce reactive 

oxirane ring. These plant oil-based epoxides are sustainable, renewable and biodegradable that can replace petroleumderived 

materials in numerous industrial applications, such as plasticizer, lubricant and in coatings formulations. In 

present work wild safflower oil (WSO) with an iodine value of 155(g I2/100g), and containing 13% oleic acid (C 18:1) 

and 72% linoleic acid (C 18:2), was epoxidised using a peroxy acid generated in situ by the reaction of aqueous hydrogen 

peroxide and carboxylic acid in presence of strongly acidic cation exchange resin, Amberlite ® IR-122. Acetic acid was 

found to be a better oxygen carrier than formic acid and the use of catalyst improved the epoxide yield. The influence of 

various reaction parameters such as temperature, stirring intensity, catalyst loading, and molar reactant ratio exerted on 

the epoxidation reaction was examined to optimize the condition for achieving maximum epoxy group formation. The 

formation of the epoxide adduct was confirmed by FTIR spectral analysis. 

The rate of epoxidation was not substantially affected with stirring speed beyond 2000 rpm under the given conditions. 

A high temperature of above 60 o C is detrimental since at continued reaction it accelerated the rapid destruction of 

oxirane rings. Higher concentrations of acetic acid and hydrogen peroxide (above 0.5 & 1.5 mol/mol of ethylenic 

unsaturation respectively) are also unfavorable as they lead to epoxy ring opening. The study shows that a relative 

conversion to epoxide ring moiety of 85% can be achieved by using the optimum molar ratio 1:0.5:1.5 (ethylenic 

unsaturation: acetic acid: hydrogen peroxide) at temperature 60 o C and 2000rpm. 

Key words: Epoxidation, wild safflower oil, acidic cation exchange resin, reaction parameters. 

INTRODUCTION 

Vegetable oils and fats, the important renewable 

resources, are biodegradable, low in cost and readily 

available. A number of methods such as chemical and 

enzymatic modification of oils have been suggested for 

improving their properties. The modified oils serve as 

feedstock that can replace petroleum-derived materials 

in many applications [1] . Thus, there is an immediate 

need of attention towards effective utilization of these 

biobased products taking into the consideration of 

current environmental harm and steadily rising price of 

petroleum. Moreover, this trend will reduce the 

dependence on imported petroleum and will promote 

the sustainable agricultural initiative. 

The unsaturation present in fatty acid molecule of the 

vegetable oil can be used to introduce various 

functional groups by carrying out chemical reactions. 

Among them, epoxidization is one of the most widely

Pawan D. Meshram et al /Int.J. ChemTech Res.2011,3(3) 1153 

used reaction. Epoxidation introduces the high strain 

energy three-membered oxirane ring into the 

unsaturated part of the oil molecule, thereby increasing 

its complexity and chemical reactivity with a variety of 

compounds such as amines and carboxylic acids 

[2, 3] 

and serves as a chemical intermediate for the 

preparation of derivatives that would be difficult to 

obtain directly from the unsaturated bonds of fatty 

acids [4] . This leads to a wide spectrum of commercial 

uses for epoxides. There are several methods for 

producing epoxides from vegetable oils, fatty acids 

and methyl esters. These includes epoxidation with 

percoarboxylic acid generated in situ in the presence of 

acids or enzymes as catalysts [5,6] , epoxidation with 

organic and inorganic oxidants such as potassium 

peroxomonosulphate, meta-chloroperoxybenzoic acid 

and ethyl methydioxirane [7,8,9,10] , epoxidation with 

halohydrins for the epoxidation of olefins with 

electron-deficient double bonds and epoxidation with 

molecular oxygen [6] . From process, environmental 

safety and efficiency point of view epoxidation of 

vegetable oils in one step, i.e., with peroxy acid 

generated in situ from carboxylic acid (formic/acetic 

acid) with hydrogen peroxide in the presence of acid 

catalyst is widely used on an industrial scale. 

However, the use mineral acid as catalyst in 

epoxidation is inefficient because of problems 

associated with separation of the catalyst from the 

reaction product. The process can be made competitive 

with the use of ion-exchange catalyst instead of 

traditional homogeneous one in epoxidation of 

unsaturated compounds [11] . Epoxidized vegetable oils 

are widely used in polymer chemistry because of their 

excellent plasticizing action for poly (vinyl chloride) 

and as effective component for stabilizing polymer 

formulations [12,13] . Epoxides find industrial application 

as diluents [14] , lubricants [15] and coatings [16] . 

Industrially epoxides have been prepared from castor, 

linseed, rapeseed, soybean and sunflower oils 

containing high to moderate unsaturation. The progress 

on the utilization of other seed oils of semidrying 

nature like flax, canola, karanja, jatropha, rubber seed, 

cottonseed, olive, corn etc. for epoxide synthesis at 

laboratory level is very encouraging towards 

development of an efficient and safe epoxidation 

process. Safflower is an important oil seed crop of the 

tropical countries, which belongs to the family 

Compositae or Asteraceae and genus Carthamus. C. 

tinctorius is the only cultivated species of this genus 

which is used primarily for edible oil and the other 

sister species are wild and weed. Taking into account 

of higher proportion of unsaturation in fatty acid 

composition of the safflower oil, it is characterized as 

semidrying and finds its use in paints, textile and 

leather industries [17, 18] . India is the largest producer of 

safflower in the world with an area of 3.63 ×10 6 

hectares, production of 2.29 ×10 6 tonnes and 

productivity of 631 kg/ha [19] . However, being almost 

completely utilized as edible oil in India, there is an 

increased attention of researchers to search the low 

cost renewable resource as alternate to the cultivated 

safflower oil. Among the wild & weed species, C. 

oxyacantha and C. palaestinus were reported to be 

progenitor of C. tinctorius, being closely related to 

cultivated species with similarity coefficient more than 

0.95 [20] . The wild species C. oxyacantha is 

widespread in Turkey, subtropical regions of western 

Iraq, Iran, North-west India, throughout kazakistan, 

Turkmenistan and Uzbekistan [21] . In India wild 

safflower grows in the arid regions of North India 

particularly in Punjab and Uttar Pradesh. It is winter 

growing anuual plant with distribution in the wheat 

fields near Bhognipur, Bhigapur, Pokhrayan, 

Ghatampur and adjoining areas of Kanpur district. 

The fatty acid composition of raw and refined oil 

extracted from the seeds of C. oxyacantha is reported 

by Banerji et.al. [22] . The exploitation of wild safflower 

seed oil (WSO) in preparation of epoxides is still the 

area not discussed. This paper investigates the wild 

safflower seed oil epoxide (EWSO) synthesis 

methodology with the use of strongly acidic cation 

exchange resin (Amberlite ® IR-122) as catalyst. Both 

formic acid and acetic acid were used as carboxylic 

acids and a screening of four acid–catalyst 

combinations were done to find out the most efficient 

one. The influence of various reaction parameters such 

as temperature, stirring speed, catalyst loading, acetic 

acid-to-ethylenic unsaturation molar ratio, hydrogen 

peroxide-to-ethylenic unsaturation molar ratio on 

epoxidation reaction is focused with intention to 

optimize the condition for maximum epoxy yield with 

highest conversion of double bonds to oxirane rings. 

MATERIALS AND METHODS 

Materials 

About 20 Kg seeds of C. oxyacantha were collected 

from the adjoining regions of Punjab district and 

extracted in lab-scale immersion-percolation type 

batch extractor (Fig.1) with Rankosolv SG (distillation 

range 63.0-70.0°C; water content, as determined by 

KF method, 0.1%) solvent obtained from Rankem 

RFCL, New Delhi. The five number of extraction 

stages (20 min for each stage) were evaluated, below 

the boiling point of solvent with miscella recycle flow 

rate of 9mL/sec, for oil yield . The seeds yielded 26% 

of pale yellow oil, which after due analytical study was 

used for epoxidation as such without any refinement. 

The chemicals glacial acetic acid, 98% and formic 

acid, 90% were obtained from Qualigens India Ltd., 

Mumbai. AR grade hydrogen peroxide (30 wt.%),


Iodine monochloride and Wij’s solution were procured from S.D. Fine Chemicals Ltd., Mumbai. 

Figure 1: Lab-scale immersion-percolation type batch extractor 

HBr in acetic acid (33 wt.%) was obtained from 

Fischer Scientific, Mumbai and then diluted with 

glacial acetic acid to make 0.1N HBr. Strongly acidic 

cation exchange resin (Amberlite ® IR-122, sulfonic 

acid functionality) with total cation exchange capacity 

of 2.1meq/mL was procured from Sigma–Aldrich 

(USA). 

Epoxidation experiments 

The epoxidation of WSO was carried out in batch 

mode in a glass reactor consisting of a four-necked 

round bottom flask of 500ml capacity. A motor driven 

speed regulator stirrer was inserted in the reactor 

through the central neck while other neck was used for 

thermo-electrode. A condenser was fitted to the reactor 

through third neck and the fourth neck is used for 

dropping the raw materials into the reactor. The reactor 

was heated by an electric heating mantle having 

special arrangement for smooth and accurate control of 

the temperature within ±1°C of the desired 

temperatures. 

The epoxidation method reported by Dalai et.al. [23] 

was used, and the same procedure was employed for 

all of the experimental runs dealing with different 

parameters. The epoxidation reactions were first 

carried out with both formic acid and acetic acid as 

carboxylic acids and with & without catalyst (IR-122) 

combinations. These initial epoxidation experiments 

were conducted to select the most active carboxylic 

acid-catalyst combination. Further epoxidation runs 

were carried out with the best reagent–catalyst 

combination using the following range of parameters: 

stirring speeds, 1000-2500 rpm; temperature, 40-80 o C; 

hydrogen peroxide-to-ethylenic unsaturation molar 

ratio, 0.5-2.0 and acetic acid-to-ethylenic unsaturation 

molar ratio, 0.3-1.0; catalyst loading (expressed as the 

weight percentage of WSO used), 5-20%. 

A calculated amount of WSO (35 g) was introduced in 

the reactor and heated with agitation to a temperature 

of 40°C for 15 min. The requisite amount of 

acetic/formic acid (carboxylic acid to ethylenic 

unsaturation molar ratio, 0.5:1) and catalyst (20 wt.%) 

were added, and the mixture was continuously stirred 

at 2000 rpm for 30 min. Then, 33.76 g of 30% aqueous 

hydrogen peroxide (1.5 mole of hydrogen peroxide per 

mole of ethylenic unsaturation) was added dropwise to 

the reaction mixture at a rate such that the hydrogen 

peroxide addition was completed over a period of 30 

min with gradual increase in temperature to 60°C. 

After complete addition of hydrogen peroxide, the 

reaction was continued for 8 hours, considering the 

completion of addition of hydrogen peroxide to be the 

zero time, at controlled temperature 60±1°C with 

continuous stirring to ensure fine dispersion of oil. 

The course of the reaction was followed by 

withdrawing samples at regular intervals, the first


being taken after one hour since zero time. The 

collected samples were washed with warm water 

successively to make them acid free and extracted with 

diethyl ether in a separating funnel to enhance the 

separation of the oil product from water phase and 

dried using a rotary evaporator. The progress of 

epoxidation was monitored by determination of 

oxirane content and iodine value of the washed 

aliquots of the reaction mixture. Two replication of 

each experiment were performed alongside to 

determine the percentage deviation between two 

experimental results and the deviation was found to be 

less than 5%. 

Analytical methods 

Acid value, Saponification value, Iodine value and 

Specific gravity of the raw WSO were determined 

according to AOCS Method Cd 3d-63, AOCS Method 

Cd 3-25, AOCS Method Cd 1b-87 and MS 817:1989 

respectively. The percentage of oxirane oxygen 

content was determined using AOCS Official Method 

Cd 9-57 (1997) under which the oxygen is titrated 

directly with hydrogen bromide solution in acetic acid. 

The conversion of double bonds to oxirane rings were 

observed under FTIR spectra, measured on Shimazdu 

FTIR-8400spectrometer equipped with DLATGS 

detector and a KBr beam splitter into the range of 4000 

to 400 cm −1 . The absorbance spectra for each analysis 

were averaged over 32 scans with a nominal 4 cm −1 

resolution. 

From the oxirane content, the percentage relative 

conversion to oxirane was determined using the 

following formula [3] : 

Relative conversion to oxirane (RCO) 

= [OOex / OOth] × 100 ----------------------------(1) 

where OOex is the experimentally determined content 

of oxirane oxygen and OOth is the theoretical 

maximum oxirane oxygen content in 100 g of oil, 

which was calculated to be 8.90% using the following 

expression [24] : 

OOth = {(IVo / 2Ai) / [100 + (IVo / 2Ai) × Ao]} 

× Ao × 100 ----------------------------(2) 

where Ai (126.9) and Ao (16.0) are the atomic weights 

of iodine and oxygen respectively and IVo is the initial 

iodine value of the oil sample. 

RESULTS AND DISCUSSION 

The properties of WSO, with fatty acid composition, 

were analyzed as follows: specific gravity = 0.922 (at 

25 o C); acid value (mg KOH/g) = 2.2; iodine value (g 

I2/100 g) = 155; saponification value (mg KOH/g) = 

194; oleic acid, C 18: 1 = 13%; linoleic acid, C18:2 = 

73%. 

Effect of carboxylic acid 

In situ epoxidation reactions were carried out with 

both formic acid and acetic acid as carboxylic acids; 

with and without catalyst reagent with 1:0.5:1.5 molar 

ratio of ethylenic unsaturation: carboxylic acid: 

hydrogen peroxide at a temperature 60°C. The 

variations of iodine values with reaction time for 

epoxidation of WSO with acidic ion exchange resin 

IR-122 as catalyst is shown in Fig.2. The mechanism 

of double bond conversion to epoxy ring in 

[25] 

epoxidation reaction as proposed by Gan et.al. is 

as follows: 

The excess reagents can react with the epoxy rings to 

cause unwanted side reactions as depicted below [1] : 

From Fig.2 it can be shown that the relative conversion 

of ethylenic unsaturation is faster in presence of acetic 

acid than formic acid and addition of catalyst improves 

the rate of reduction of iodine value (IV). With formic 

acid/IR-122 combination, a slightly elevated reduction 

in IV is achieved as compared with the use of acetic 

acid with no resin. Fig.3 shows the relative percentage 

conversion to oxirane as function of time, from which 

it is inferred that formic acid/IR-122 combination is 

less effective than acetic acid and acetic acid/IR-122 

combination towards ethylenic unsaturation 

conversion to oxirane. The 65.4% conversion to 

oxirane was obtained for formic acid/IR-122 after 8 

hours while with acetic acid the conversion was 72%. 

Acetic acid/IR-122 combination resulted into 85% 

conversion to oxirane with corresponding iodine 

conversion of 87.2% was considered a better 

combination for epoxidation of WSO with aqueous 

hydrogen peroxide. Further experiments were, 

therefore, carried out with acetic acid/ IR-122 to study 

the effect of various parameters on conversions to 

oxirane oxygen and the conversion of iodine value.


Figure 2: Variation of iodine value with time during epoxidation of WSO with acidic ion exchange resin IR- 

122 as catalyst. 

Figure 3: Activities of carboxylic acids in the epoxidation of WSO with acidic ion exchange resin IR-122 as 

catalyst. Conditions: Temperature, 60°C; carboxylic acid-to-ethylenic unsaturation molar ratio, 0.5:1; 

hydrogen peroxide-to-ethylenic unsaturation molar ratio, 1.5:1; catalyst loading, 20 wt.% of oil; stirring 

speed, 2000 rpm 

Effect of stirring speeds 

Agitation rate is an important parameter because this 

factor substantially affects the conversion to oxirane. 

Epoxidation was performed at different speeds varying 

from 1000-2500 rpm to study the effect of agitation 

rate on mass transfer resistance. In reaction, 35 g of 

WSO was treated with 13.76 g of hydrogen peroxide, 

5.95g of acetic acid and 7g resin, as catalyst at 60°C. 

The % IV reductions and relative percentage 

conversions to oxirane at different speeds are shown 

inTable-1 and Fig.4 respectively. The oxirane 

formation rate improved with agitation rate upto 2000 

rpm but beyond that no significant control was 

observed under the given conditions. Thus, all 

experiments were performed at 2000 rpm assuming 

that the reaction is free from mass transfer resistance 

beyond 2000 rpm.


Table 1: Relative conversion to oxirane at different stirring speeds 

Stirring Speeds, rpm 

1000 1500 2000 2500 

Time (h) 4 8 4 8 4 8 4 8 

Oxirane oxygen a (%) 6.42 6.87 7.00 7.23 7.53 7.70 7.62 7.40 

Iodine value b,c (g I2/100g) 41.2 32.9 21.2 19.0 22.6 19.8 24.5 20.6 

% Iodine value conversion d (A) 73.4 78.8 86.3 87.7 85.4 87.2 84.2 86.7 

a Experimentally determined oxirane oxygen content; b IV0,Initial iodine value=155; 

c IV Experimentally determined iodine value; 

d Conversion of ethylenic unsaturated bonds as related to IV0 calculated as A={(IV0 –IV) ×100/ IV0} 

Table 2: Effect of temperature on iodine value conversion 

Temperature ( o C) 

40 50 65 80 

Time (h) 4 8 4 8 4 8 4 8 


Iodine Value b,c (g I2/100g) 93.6 66.0 55.4 48.0 18.9 16.9 15.2 12.2 

% Iodine conversion d (A) 39.6 57.5 64.3 69.1 87.8 89.1 90.19 92.13 

Figure 4: Effect of stirring speeds on the relative conversion to oxirane. Conditions: Temperature, 60°C; acetic 

acid to ethylenic unsaturation molar ratio, 0.5:1; hydrogen peroxide to ethylenic unsaturation molar ratio, 1.5:1; 

catalyst loading, 20 wt.% of oil 

Effect of temperature 

The effect of reaction temperature on the yield of 

oxirane content was investigated (Table-2). Reactions 

at the molar ratio of 1:0.5:1.5 (ethylenic unsaturation: 

acetic acid: H2O2) were performed at five different 

temperatures, namely 40, 50, 60, 65 and 80 o C. Being 

exothermic in nature the epoxidation reaction may 

cause an excessive temperature rise and pose serious 

reaction control related issues like potential explosion 

hazards. In order to have better control over the 

reaction, the H2O2 was added to the mixture when the 

temperature was about 10 o C below the desired reaction 

temperature. The temperature increased thereafter to 

actual reaction temperature, and was maintained there 

until the completion of reaction. From Fig.5, it is 

evident that increase in the temperature favored 

epoxidation reaction and a maximum of 92.3% 

conversion of iodine value was obtained at 80 o C after a 

reaction time of 4 hours. The relative conversion to 

oxirane was found to increase with increase in 

temperature but the epoxy functionality was retained 

more at lower reaction temperature. The oxirane 

content of the EWSO, synthesized at 60 o C reached a 

maximum of 85.6 % after 6 hours of reaction and 

oxirane cleavage was very mild when the reaction 

continued further. At 65 o C, although the epoxidation 

rate not improved much, but a sharp epoxy ring 

breaking was observed after 4 hours of continuation of 

reaction. A similar trend appeared at higher reaction 

temperature and longer reaction durations. Therefore, a 

temperature of 60 o C was considered optimal for the 

epoxidation reaction under investigation.


Table 3: Effect of catalyst loading on iodine value conversion 

AIER, IR122 loading (%) 

5% 10% 15% 20% 

Time (h) 1 4 1 4 1 4 1 4 



% Iodine value conversion d (A) 50.4 66.9 53.4 73.6 59.8 78.9 68.1 85.4 

Figure 5: Effect of temperature on the relative conversion to oxirane. Conditions: acetic acid to ethylenic 

unsaturation molar ratio, 0.5:1; hydrogen peroxide to ethylenic unsaturation molar ratio, 1.5:1; catalyst 

loading, 20 wt.% of oil; stirring speed, 2000 rpm 

Effect of catalyst loading 

In general, increasing the solid catalyst loading leads 

to increase in both the total active matter and the total 

surface area of the catalyst. The active moieties present 

in catalyst increases the rate of epoxidation with 

increase in the catalyst concentration in the reaction 

system. In our experimentation, IR-122 resin (16-50 

wet mesh size, macroreticular form) was used as 

catalyst and the effect of catalyst loading on the 

relative conversion to oxirane is presented in Fig.6. 

This figure shows that the conversion of ethylenic 

unsaturation to oxirane increases rapidly with catalyst 

dosage in the beginning and very slowly towards the 

end of the reaction. The relative conversion to oxirane 

increased from 64 to 75% with increasing dosage of 

resin from 5 to 15% after 4 hours of reaction. With 

use of 10% resin a slight oxirane cleavage is observed 

after 3 hours of reaction and maximum conversion is 

72.9%, only 2 units less than that obtained with 15% 

catalyst loading. However, the maximum conversion 

of 84% was obtained with 20% catalyst loading under 

identical conditions and the product has stable oxirane 

ring. Therefore, 20% catalyst loading was considered 

to be optimum for the epoxidation reaction. 

Figure 6: Effect of catalyst loading on the relative 

conversion to oxirane. Conditions: Temperature, 

60°C; acetic acid to ethylenic unsaturation molar 

ratio, 0.5:1; hydrogen peroxide to ethylenic 

unsaturation molar ratio, 1.5:1; stirring speed, 2000 

rpm


Table 4: Effect of acetic acid-to-ethylenic unsaturation molar ratio on iodine value conversion 

Acetic acid to ethylenic unsaturation molar ratio 

0.3 0.5 0.8 1.0 

Time (h) 4 8 4 8 4 8 4 8 



% Iodine conversion d (A) 62.9 78.8 85.4 87.2 86.2 90.3 88.0 90.8 

Figure 7: Effect of acetic acid to ethylenic unsaturation molar ratio on the relative conversion to oxirane. 

Conditions: Temperature, 60°C; hydrogen peroxide to ethylenic unsaturation molar ratio, 1.5:1; catalyst 

loading, 20 wt. % of oil; stirring speed, 2000 rpm 

Effect of acetic acid to ethylenic unsaturation molar 

ratio 

Optimization of acetic acid concentration was 

investigated at 0.3, 0.5, 0.8 and 1.0 mole per mole of 

ethylenic unsaturation for rate conversion to oxirane 

with respect to 1.5 mole of H2O2 per mole of 

unsaturation. Acetic acid acts as the oxygen carrier and 

gets regenerated once epoxidation reaction takes place. 

However, it can also act as reactant in hydrolysis of the 

oxirane ring formed. Therefore, an optimum level of 

acetic acid is desired to speed up the conversion to 

oxirane ring with minimal epoxy ring breaking. The 

influence of acetic acid concentration on the relative 

conversion to oxirane is shown in Fig.7. Increasing 

acid concentration was found to increase the iodine 

value conversion (Table-4) and leads to more 

production of peracetic acid. The higher conversion 

rate of the double bond to epoxide was observed with 

increased mole ratio of acetic acid used. The reaction 

conversion of 73.7% was achieved within first hour 

when 1.0 mole acetic acid was used while the same 

conversion was obtained after 8 hour of reaction for 

0.3 mole. However, considering the stability of epoxy 

rings, the use of higher acid concentrations is of no 

significance as the excess acid promotes the hydrolysis 

of the epoxide. From Fig.7 it can be seen that an acidto-ethylenic 

unsaturation molar ratio of 0.5 is optimum 

with a moderately high rate of epoxidation reaction 

and negligible ring-opening reaction. 

Table 5: Effect of hydrogen peroxide-to-ethylenic unsaturation molar ratio on iodine value conversion 

Hydrogen peroxide to ethylenic unsaturation molar ratio 

0.5 1.0 1.5 2.0 

Time (h) 4 8 4 8 4 8 4 8 



% Iodine conversion d (A) 44.8 49.3 58.2 70.6 85.4 87.2 89.4 91.2


Figure 8: Effect of the hydrogen peroxide to ethylenic unsaturation molar ratio on the relative conversion to 

oxirane. Conditions: Temperature, 60°C; acetic acid to ethylenic unsaturation molar ratio, 0.5:1; catalyst 

loading, 20 wt. % of oil; stirring speed, 2000 rpm 

Effect of hydrogen peroxide to ethylenic 

unsaturation molar ratio 

The effect of different mole ratios of H2O2-to-ethylenic 

unsaturation on rate of oxirane formation and iodine 

conversion was studied by carrying out a series of 

reactions (Table-5). As seen in Fig.8 the reaction rate 

increased with an increase in concentration of H2O2 in 

the reaction. However; although the maximum 

conversion (91.2 %) of double bonds to epoxide rings 

was achieved with 2.0 mole of H2O2 concentration 

after 5 hours, it also tend to destroy the epoxy rings 

when reaction was continued further. For a lower H2O2 

dosing of 0.5 and 1.0 mole, the maximum oxirane 

level and initial epoxidation rates were significantly 

lower as compared to that obtained with use of 1.5 

mole H2O2. Moreover, the epoxy rings formed for 

1.5:1 mole ratio of H2O2 -to-ethylenic unsaturation 

shows excellent stability. Therefore, the optimal 

hydrogen peroxide-to-ethylenic unsaturation molar 

ratio was found to be 1.5 mol/mol, with a relative 

conversion to oxirane of 86.5% and iodine value 

conversion of 87.2% after 8 hours of reaction. 

Fourier transform infrared (FTIR) spectroscopy 

analysis 

Shimazdu FTIR-8400 spectrometer was used for 

monitoring the disappearance of double bonds and 

formation of epoxy groups during the reaction by 

qualitative identification of main signals. Only two 

spectra are analyzed: the raw oil, WSO and epoxide 

adduct, EWSO (Fig.9A & 9B, respectively), to show 

the changes in their functional groups. For WSO the 

characteristic peaks at 3008 cm -1 , 1650 cm -1 and 

721cm -1 are attributed to the stretching vibration of the 

double bonds: =C-H, C=C, cis-CH=CH, respectively. 

S. Hernandez-Lopez et.al. [26] reported the diminution 

of peak, C=C-H stretching at 3020 cm −1 after 

epoxidation reaction, which supports our study where 

the almost complete disappearance of double bonds 

band at 3008 cm −1 at 60 0 C after 8 h was observed. This 

confirms that almost all the C=C-H had taken part in 

the epoxidation reaction. Also, there is decrease in the 

intensity of the other important unsaturated bond 

signals in comparison with the unreacted oil, giving 

reliable support of its chemical transformation to an 

oxirane ring. The presence of new peaks in the FTIR 

spectrum of WSFO at 831 cm −1 , attributed to the 

epoxy group, confirmed the success of the epoxidation 

reaction of WSO. Vleck and Petrovic [27] reported the 

presence of epoxy groups at 822–833 cm −1 , which 

agrees well with this study. The other new peak at the 

3470 cm −1 was attributed to the hydroxyl functional 

group, derived from the epoxy functional group via 

partial epoxy ring opening reaction. The intensity of 

the 3470 cm −1 band indicated the extent of hydrolysis 

of EWSO. The epoxy ring opening reaction could 

occur either by acid catalysis in the presence of water 

associated with aqueous solution of H2O2 used [28] . 

The hydrolysis of the ester groups during epoxidation 

reaction in oils is the main side reaction. The band 

corresponding to carboxylic acid group is located at 

1650 cm -1 and is usually very intense even at low 

carboxylic group concentration [29, 30] . In case of 

hydrolysis, a carboxylic acid functional group is 

formed and this carbonyl group will appear near but 

differentiable of the ester carbonyl stretching C=O in 

the glyceride moiety at 1744 cm -1 . However; in the 

course of the epoxidation reaction carried out in our


study, no evidence of the carbonyl from carboxylic acid group signal was observed. 

Figure 9: FTIR spectra of (A) wild safflower oil and (B) and epoxidised wild safflower oil. Epoxidation 

Conditions: Temperature, 60 o C, carboxylic acid (acetic acid)-to-ethylenic unsaturation molar ratio, 0.5 : 

1;hydrogen peroxide-to-ethylenic unsaturation molar ratio, 1.5 : 1; catalyst loading, 20 wt. % of oil; reaction 

time, 8 h; stirring speed, 2000 rpm 

CONCLUSION 

The results of the present investigation shows that 

WSO can be successfully utilized for epoxidation 

using peroxy acid generated in situ. Acetic acid–IR- 

122 combination was found to be most effective for 

higher epoxide yield at shorter reaction time. The 

optimized parameters to get higher degree of 

epoxidation with minimum epoxy ring breaking were 

noted as temperature of 60°C, stirring speed 2000 rpm 

ensuring kinetically control of reaction, an acetic acid 

to ethylenic unsaturation molar ratio of 0.5:1, a 

hydrogen peroxide to ethylenic unsaturation molar 

ratio of 1.5:1, and a catalyst (IR-122) loading of 20 

wt% of WSO. The completion of reaction was 

supported by FTIR spectral analysis. The epoxy 

signals were well identified and intensity of the signals 

due to the double bonds vibrations was evidenced by 

the spectroscopic techniques used. Under these 

optimum conditions, 7.87% oxirane oxygen content in 

synthesized ESWO was obtained. The synthesized 

epoxide WSO is an attractive intermediate for the 

preparation of various derivatives of industrial 

importance.


REFERENCES 

1. Le P. L., Wan Yunus W.M.Z., Yeong S. K., 

Dezulkelfly K. A., Lim W. H., “Optimization of 

the epoxidation of methyl ester of palm fatty acid 

distillate” J. Oil Palm Res., 2009, 21, 675-682. 

2. Holser R. A., “Transesterification of epoxidized 

soybean oil to prepare epoxy methyl esters”, Ind. 

Crops and Products, 2008, 27, 130-132. 

3. Goud V.V., Mungroo R., Pradhan N.C., and Dalai 

A.K., “Modification of epoxidised canola oil”, 

Asia-Pacific J. Chem. Eng., 2011, 6, 14–22. 

4. Dahlke B., Hellbardt S., Paetow M., Zech W.H., 

“Polyhydroxy fatty acids and their derivatives 

from plant oils”, J. Am. Oil Chem. Soc., 1995, 72, 

349–353. 

5. Okieimen F.E, Pavithran C., Bakare I.O., 

“Epoxidation and hydroxylation of rubber seed oil: 

one-pot multi step reactions”, Euro. J. Lipid Sci. & 

Tech., 2005, 107, 864-870. 

6. Patwardhan A.V., Goud V.V., Pradhan N.C., 

“Epoxidation of Karanja (Pongamia glabra) Oil by 

H2O2”, J. Am. Oil Chem. Soc., 2006, 83, 247-252. 

7. Carlson K.D., Kleiman R., Bagby M.O, 

“Epoxidation of lesquerella and limmanthes 

(meadowfoam ) oil” , J. Am. Oil Chem. Soc., 

1994, 71, 175-182. 

8. Marcel S.F., Lei K. J. and Mohammad K.P., 

“Epoxidation reactions of unsaturated fatty esters 

with peroxomonosulphate”, Lipids, 1998, 33, 633- 

637. 

9. Sonnet P. E. and Foglia T., “Epoxidation of natural 

triglycerides with ethyl methydioxyrane”, 

J. Am. Oil Chem. Soc., 83, 835-840. 

10. Aerts A. J., Jacob P.A., “Epoxide yield 

determination of oils and fatty acid methyl esters 

using 1 H NMR”, J. Am. Oil Chem. Soc., 2004, 81, 

841-846 

11. Gurbanov M. S., and Mamedov B. A., 

“Epoxidation of Flax Oil with Hydrogen Peroxide 

in a Conjugate System in the presence of Acetic 

Acid and Chlorinated Cation Exchanger KU-2×8 

as Catalyst”, Russian J. App. Chem., 2009, 82, 

1483-1487. 

12. Khot S. N., Lascala J. J., Can E., Moyre S. S., 

Williams, G. I., Palmese ,G. R., Kusefoglu, S. H. 

and Wool, R.P., “Development and Application of 

Triglyceride-Based Polymers and Composites”, J. 

Appl. Polym. Sci., 2001, 82, 703-723. 

13. Biermann U., Friedt W., Lang S., Luhs W., 

Machmuller G., Metzger J. O., Klaas M. R., 

Schafer H.J. and Schneider M.P., “New Synthesis 

with Oils and Fats as Renewable Materials for the 

Chemical Industry”, Agew. Chem. Int. Ed., 2000, 

39, 2206-2224. 

14. Muturi P., Wang D., and Dirlikov S., “Epoxidized 

vegetable oils as reactive diluents. I. Comparison 

of vernonia, epoxidized soybean and epoxidized 

linseed oil”, Progress in Organic Coatings, 1994, 

25, 85-94. 

15. Adhvaryu A., Erhan S.Z., “Epoxidized soybean oil 

as a potential source of high-temperature 

lubricants”, Industrial Crops and Products, 2002, 

15, 247-254. 

16. Soucek M. D., Johnson A. H., Wegner J. M., 

“Ternary evaluation of UV-curable seed oil 

inorganic/organic hybrid coatings using 

experimental design” Progress in Organic 

Coatings, 2004, 51, 300-311. 

17. Zhang L.P., “Safflower: a versatile plant”, IV 

International Safflower Conf., Bari, 2-7 June, 

1997, 311-329. 

18. Hilker D., Bothe J. P. and Warnecke H.J., 

“Chemo-Enzymatic Epoxidation of Unsaturated 

Plants Oils”, Chemical Engineering Science, 2001, 

56, 427-432 

19. Anjani K., Mukta N. and Lakshmamma P., “Crop 

improvement: In Research Achievements in 

Safflower”, Directorate of Oilseeds Research, 

Hyderabad, India, 11. 

20. Ravikumar R.L., Soregaon C.D. and Satish D., 

“Molecular diversity analysis of five different 

species of genus Carthamus”, National Seminar on 

Changing Global Vegetable Oils Scenario: Issues 

and Challenges before India”, Directorate of 

Oilseeds Research, Hyderabad, India, 29-31 

January, 2007, 2-4. 

21. Ashri A., Zimmer D.E., Urie A.L., Cahaner A. and 

Marani A., “Evaluation of world collection of 

safflower Carthamus tinctorius L. yield and yield 

components and their relationships”, Crop Sci., 

1974, 14, 799-802. 

22. Banergy R., Pandey V. and Dixit B. S., “Wild 

Safflower: An alternative source of safflower oil”, 

J. Oil Tech. Assoc. Ind., 1999, 31, 59-60. 

23. Dalai A.K., Mungroo R., Pradhan N.C., Goud 

V.V. ,“ Epoxidation of canola oil with hydrogen 

peroxide catalyzed by acidic ion exchange resin”, 

J. Am. Oil Chem. Soc.,2008, 85, 887-896. 

24. Petrovic Z. S., Zlatanic A., Lava C.C., 

Sinadinovic-Fiser S., Epoxidation of soybean oil in 

toluene with peroxoacetic and peroxoformic acids. 

Kinetics and side reactions”, Eur. J. Lipid Sci. & 

Tech., 2002, 104, 293–299.


25. Gan L.H., Goh S.H., and Ooi K.S., “Kinetics 

studies of epoxidation and oxirane cleavage of 

palmolein methyl esters”, J. Am. Oil Chem. Soc., 

1992, 69, 347-351. 

26. S. Hernandez-Lopez, E. Martin del Campo-Lopez, 

V. Sanchez-Mendieta, F. Urena-Nunez and E. 

Vigueras- Santiago, “Gamma Irradiation on 

Acrylated-Expoxidized Soybean Oil: 

Polymerization and Characterization”, Adv. in 

Tech. of Mat. and Mat. Proc. J., 2006, 8, 220-225. 

27. Vlcek T., Petrovic Z.S., “Optimization of the 

chemoenzymatic epoxidation of soybean oil”, J. 

Am. Oil Chem. Soc., 2006, 83,247–252 

28. Pares X.P.X., Bonnet C., and Morin O., “Synthesis 

of New Derivatives from Vegetable Oil Methyl 

***** 

Esters via Epoxidation and Oxirane Opening”, in 

Recent Developments in the Synthesis of Fatty 

Acid Derivative (Knothe, G. and Derksen, J.T.P., 

Eds.) AOCS Press, 1999, Champaign, IL, 141-156. 

29. G. Lopez Tellez, E. Vigueras-Santiago, S. 

Hernandez-Lopez, “ Characterization of 

epoxidized linseed oil at different percentage”, 

Surface and Emptiness, 2009, 22, 5-10. 

30. G. Lopez-Tellez, E. Vigueras-Santiago, S. 

Hernandez-Lopez, B. Bilyeu, “Synthesis and 

thermal cross linking study of partially aminated 

epoxidized linseed oil”, Designed Monomers and 

Polymers, 2008, 11, 435-445.

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