J. Nig. Soc. Phys. Sci. 4 (2022) 16–19

Journal of the
Nigerian Society

of Physical
Sciences

Heterogeneous Catalyzed Synthesis of Biodiesel from Crude
Sunflower Oil

Selvaraju Sivamani∗, Marwan Ahmed Sulieman Al Aamri, Aseela Musalem Awad Anthroon Jaboob, Azeezah Mohammed
Masoud Kashoob, Layal Kamall Abdullah Al-Hakeem, Mouna Salim Mhaad Said Almashany, Muna Ahmed Mohammed Safrar

Engineering Department, University of Technology and Applied Sciences (Salalah College of Technology), Salalah, Oman

Abstract

Biodiesel is the fatty acid alkyl esters that are used as the substitute for petro-diesel. The aim of the present work is to optimize biodiesel
production from plant based non-edible crude oils with methanol using heterogeneous catalyst by transesterification for its commercialization.
The factors affecting the biodiesel production from plant oils are volume of feedstock (oil), volume of alcohol (excess reactant), quantity of
calcium hydroxide (catalyst), reaction time, temperature, and agitation speed. Transesterification is the reaction between acid and alcohol to
produce ester in the presence of alkali catalyst. In this work, transesterification was carried out between crude sunflower oil and methanol in the
presence of calcium hydroxide as catalyst. Finally, the maximum conversion of 85.6% was achieved at the optimum process parameters of 2 L of
crude sunflower oil, 0.3 L methanol, 23 g of calcium hydroxide, reaction time of 24 h, temperature of 65 ◦C, and agitation speed of 100 rpm. The
results showed that crude sunflower oil could serve as potential renewable substrate for biodiesel commercialization.

DOI:10.46481/jnsps.2022.230

Keywords: Crude sunflower oil, Calcium hydroxide, Transesterification, Biodiesel

Article History :
Received: 16 May 2021
Received in revised form: 12 January 2022
Accepted for publication: 27 January 2022
Published: 28 February 2022

c©2022 Journal of the Nigerian Society of Physical Sciences. All rights reserved.
Communicated by: B. J. Falaye

1. Introduction

Biodiesel is an alternative fuel for clean combustion from
domestic and renewable resources. The fuel is a mixture of
alkyl esters of fatty acids made from pure edible vegetable oils,
pure non-edible vegetable oils, waste vegetable oils, crude veg-
etable oils, algal oils, animal fats or recycled fats [1]. Biodiesel
can be used in its pure form with little or no modification in
existing diesel engines, wherever applicable.

Biodiesel is easy to use, biodegradable, non-toxic and es-
sentially free of Sulphur and aromatics. It is generally used as

∗Corresponding author tel. no:
Email address: sivmansel@gmail.com (Selvaraju Sivamani )

a petro-diesel additive to reduce particulate, carbon monoxide,
hydrocarbon and pollutant concentrations in diesel vehicles [2].
When used as an additive, the resulting diesel fuel may be re-
ferred to as B5, B10 or B20. This is the percentage of biodiesel
that is mixed with petro-diesel. For example, B5 means that
biodiesel and petro-diesel are mixed in the ratio of 5:95 [3].

Biodiesel is produced by the process in which oils are com-
bined with alcohol (ethanol or methanol) in the presence of a
catalyst (alkali or heterogeneous) to form ethyl or methyl es-
ters. Ethyl or methyl esters of biomass can be mixed with con-
ventional diesel fuel or used as a pure fuel (100% biodiesel)
[4]. Biodiesel can be made from vegetable oil, animal fat, or
microalgae oil. The three basic ways of producing biodiesel

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Sivamani et al. / J. Nig. Soc. Phys. Sci. 4 (2022) 16–19 17

from oils and fats are as follows [5]:

1. Direct transesterification of oils or fats catalyzed by al-
kali or heterogeneous catalyst (If free fatty acid (FFA) <
2.5%)

2. Esterification of oils or fats by acid catalysis and then by
transesterification (If FFA > 2.5%)

3. Conversion of oils and fats to its fatty acids and then to
biodiesel

The most common feedstock of edible oils used to pro-
duce biodiesel are soybean oil [6], rapeseed oil [7] and palm oil
[8], which accounts for the bulk production of global biodiesel.
Other raw materials may come from non-edible sources such as
Jatropha [9], mustard [10], flax [11], and hemp [12]. Animal
fats, including sebum [13], lard [14], yellow fat [15], chicken
fat [16] and fish oil [17] derivatives, may contribute to a small
percentage of biodiesel production in the future, but their sup-
ply is limited and inefficient to raise animals for their fat.

Biodiesel can be mixed with petro-diesel in any proportion
to produce a biodiesel blend, or it can be used in a pure form.
Like petro-diesel, biodiesel works with the diesel engine with
auto-ignition and essentially requires little or no engine modifi-
cation, as biodiesel has similar properties to diesel [18]. It can
be stored as a petro-diesel and therefore does not require a sep-
arate infrastructure. The use of biodiesel in conventional diesel
engines results in a significant reduction in the emission of un-
burnt hydrocarbons, carbon monoxide and particulates. Cur-
rently, a large number of biodiesel production plants around the
world are functioning to full capacity, and a large number are
under construction or designed to meet growing global demand
[19].

Literature studies show that abundant scientific reports are
available on production of biodiesel from pure edible vegetable
oils [6-8], pure non-edible vegetable oils [9-12], waste veg-
etable oils [20-22], algal oils [23-25], and animal fats [13-17].
But, only limited literature is available on biodiesel production
from crude vegetable oils [26-27], and recycled fats [28-29].
Hence, the present work focuses on the optimization of process
parameters for production of biodiesel from plant based non-
edible crude oils with methanol using heterogeneous catalyst
by transesterification for its commercialization.

2. Materials and Methods

2.1. Materials
Crude sunflower oil was generously provided by Omani Veg-
etable Oils & Derivatives Company (LLC), Raysut, Oman. All
the chemicals used in the work are of analytical grade and the
products of VWR International. Double distilled water was
used in this study.

2.2. Methods
A known volume of crude sunflower oil (2 L) was mixed with
known volume of methanol and known quantity of calcium hy-
droxide and mixed well for certain time and temperature with
mixing. After the time is completed, the mixture was allowed

to settle for 8 h and the bottom glycerol layer was removed and
acidulated with phosphoric acid to separate glycerol, sodium
phosphate and methanol. Sodium phosphate is reacted with
water to produce phosphoric acid and recycled back. From the
top layer, the mixture of biodiesel and water with little quantity
of methanol was washed to remove excess methanol present,
and dried to remove moisture from biodiesel. Finally, FFA of
oil and biodiesel were measured and the percentage conversion
was calculated using the equation as given below:

% conversion =
(F F A in oil − F F A in biodiesel)

F F A in oil
x100

FFA was estimated following the procedure as follows [30]:
Standard solvent was prepared by mixing 25 mL diethyl ether
and 25 mL 95% ethanol, and titrated against 0.1 N KOH using
1 mL of 1% phenolphthalein solution as an indicator. 5 g of
oil was dissolved in 50 mL of standard solvent in a 250 mL
Erlenmeyer flask. The contents are titrated against 0.1 N KOH
using few drops of phenolphthalein as an indicator. The end
point is the appearance of pink color that lasts for 15 s. Then,
FFA was calculated using the equation as below:

Free f atty acid value (mg KOH/g oil)

=
T itre value x Normality o f KOH x 28.05

Mass o f oil in g

The effect of methanol (0.1-0.5 L) was studied by fixing vol-
ume of oil, mass of calcium hydroxide, time, temperature and
agitation speed at 2 L, 23 g, 24 h, 65 ◦C and 100 rpm respec-
tively. The effect of catalyst (13.8-32.2 g) was studied by fixing
volume of oil, volume of methanol, time, temperature and agi-
tation speed at 2 L, 0.3 L, 24 h, 65 ◦C and 100 rpm respectively.
The effect of time (16-32 h) was studied by fixing volume of
oil, volume of methanol, mass of calcium hydroxide, tempera-
ture and agitation speed at 2 L, 0.3 L, 23 g, 65 ◦C and 100 rpm
respectively. The effect of temperature (55-75 ◦C) was studied
by fixing volume of oil, volume of methanol, mass of calcium
hydroxide, time and agitation speed at 2 L, 0.3 L, 23 g, 24 h
and 100 rpm respectively. The effect of agitation speed (50-150
rpm) was studied by fixing volume of oil, volume of methanol,
mass of calcium hydroxide, time and temperature at 2 L, 0.3 L,
23 g, 24 h and 65 ◦C respectively.

3. Results and Discussion

Figure 1(a) shows the effect of volume of methanol on percent-
age conversion at constant values of volume of oil of 2 L, mass
of calcium hydroxide of 23 g, reaction time of 24 h, temper-
ature of 65 ◦C and agitation speed of 100 rpm. Volume of
methanol varied from 0.1 to 0.5 L. Volume of methanol was
selected based on the molar ratio of oil to methanol. From the
literature, molecular weight of oil is 292 g/mol. In transesteri-
fication reaction, oil is the limiting reactant and methanol is the
excess reactant.

According to the reaction stoichiometry, 1 mole of oil re-
acts with 3 moles of methanol to produce biodiesel and glyc-
erol. But, in practice, moles of methanol required to produce

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Sivamani et al. / J. Nig. Soc. Phys. Sci. 4 (2022) 16–19 18

Figure 1. Effect of (a) volume of methanol (b) mass of calcium hydroxide (c) reaction time (d) temperature and (e) agitation speed on percentage conversion

biodiesel is more than the stoichiometric requirement. Percent-
age conversion initially increased with increase in volume of
methanol. After 0.3 L of methanol, conversion decreased. This
is due to the fact that high content of methanol reduces the qual-
ity of biodiesel and hence, decrease in conversion was observed
[31].

Figure 1(b) shows the effect of mass of calcium hydroxide
on percentage conversion at constant values of volume of oil
of 2 L, volume of methanol of 0.3 L, reaction time of 24 h,
temperature of 65 ◦C and agitation speed of 100 rpm. Mass of
calcium hydroxide varied from 13.8 to 32.2 g. Mass of calcium
hydroxide was selected based on the mass ratio of catalyst to
oil. In transesterification reaction, oil is the limiting reactant
and methanol is the excess reactant and alkali or heterogeneous
materials as catalyst. According to the standard operating pro-
cedure, mass ratio between catalyst and oil should be between
0.5 and 2% (w/w). Percentage conversion initially increased

with increase in mass of calcium hydroxide. After 23 g of cal-
cium hydroxide, conversion decreased. This is due to the fact
that catalytic poisoning occurs at higher concentration of cata-
lyst [32].

Figure 1(c) shows the effect of reaction time on percentage
conversion at constant values of volume of oil of 2 L, volume of
methanol of 0.3 L, mass of calcium hydroxide of 23 g, temper-
ature of 65 ◦C and agitation speed of 100 rpm. Reaction time
varied from 16 to 32 h. Reaction time was selected based on the
literature. In transesterification, reaction should be carried out
between oil, methanol and catalyst for certain period of time.
Percentage conversion initially increased with increase in time.
After 24 h, conversion decreased [33].

Figure 1(d) shows the effect of temperature on percentage
conversion at constant values of volume of oil of 2 L, volume of
methanol of 0.3 L, mass of calcium hydroxide of 23 g, time of
24 h, and agitation speed of 100 rpm. Reaction temperature var-

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Sivamani et al. / J. Nig. Soc. Phys. Sci. 4 (2022) 16–19 19

ied from 55 to 75 ◦C. Reaction temperature was selected based
on the boiling point of alcohol. In transesterification, reaction
should be carried out between oil, methanol and catalyst at cer-
tain temperature. Percentage conversion initially increased with
increase in temperature. After 65 ◦C, conversion decreased.
This is due to the fact that above 65 ◦C, loss of methanol is
more which leads to the decrease in conversion [34].

Figure 1(e) shows the effect of agitation speed on percent-
age conversion at constant values of volume of oil of 2 L, vol-
ume of methanol of 0.3 L, mass of calcium hydroxide of 23 g,
time of 24 h, and temperature of 65 ◦C. Agitation speed varied
from 50 to 150 rpm. The effect of agitation speed on percentage
conversion is not significant [35].

4. Conclusion

The aim of the present work was to optimize biodiesel pro-
duction from plant based non-edible crude oils with methanol
using heterogeneous catalyst by transesterification for its com-
mercialization. Finally, the maximum conversion of 85.6% was
achieved at the optimum process parameters of 2 L of crude
sunflower oil, 0.3 L methanol, 23 g of calcium hydroxide, re-
action time of 24 h, temperature of 65 ◦C, and agitation speed
of 100 rpm. The results showed that crude sunflower oil could
serve as potential renewable substrate for biodiesel commer-
cialization.

Acknowledgments

We would like to acknowledge the management of the Uni-
versity of Technology and Applied Sciences, Oman for their
kind cooperation and support in completing the project.

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