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NIPES Journal of Science and Technology Research 2(2) 2020 pp. 178-187 ISSN-2682-5821
Characterization of Neem Seed Oil and its Biodiesel (B100)
1Taiwo, A. G.*, 1Ijaola, T. O., 1Lawal, S. O. and 1LanreIyanda, Y. A.
1Moshood Abiola Polytechnic, Science Laboratory Technology Department, P.M.B. 2210, Abeokuta, Ogun State,
Nigeria.
Article Info Abstract
Keywords:
Feedstock, Neem seed oil,
Transesterication,
Neem seed biodiesel
(B100), Methyl ester
The current socio-economic, political and environmental challenges of
fossil fuels led to alternative energy sources of bio-fuels like biogas,
bio-alcohol, biodiesel etc which are sustainable, renewable and
environmentally friendly. Neem biodiesel production involved oil
extraction from the seed, moisture/FFA reduction then base trans-
esterification reaction using the oil extracted, methanol (6:1), 1.0%
KOH at 60oC, 400 rpm for 2 hours. The physico-chemical and fuel
properties of the Neem seed oil biodiesel was analysed using standard
analytical methods, and the data statistically using SPSS version 20.0.
Most parametric values of the biodiesel were within the ASTM/EN
standards except in the oil that requires some pre-treatment. This
biodiesel can be a major contribution now and in the future by meeting
the petroleum diesel expected demand. As a result of this, it can be
applied in diesel engines, plants with little or no modification and can
also extend the life of diesel engines due to its more lubricating
property.
Article history:
Received 18 April 2020
Revised 02 May 2020
Accepted 03 May 2020
Available online 01 June 2020
ISSN-2682-5821/© 2020 NIPES Pub.
All rights reserved.
178

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2(2) 2020 pp. 178 - 187
1. Introduction
Everything in essence, is about energy. There is no doubt that energy is fundamental in
development [1]. It is vital for internal and external security of a country and issues which are the
core of environmental, socio-economic and political security challenges. There is concern that
availability of petroleum products may be limited, declined in the nearest future and also continue
to be expensive due to the massive increase in the fuel demand. An alternate fuel must be
developed to reduce the gap between the fuel demand and fuel availability. Bio-fuels derived from
oils and fats are found to be the most promising alternative fuel to petroleum diesel. Bio-fuels can
be employed in existing diesel engines with minor or no modifications, also it can extend the life
of diesel engines because it is more lubricating than petroleum diesel fuel [2]. Among the bio-fuels
are biogas, bio-alcohol, biodiesel but bio-alcohol seems to be the most common. However, there is
growing main concern among scientists and economists, business people, managers and
governments worldwide regarding shortages of energy, material resources and the increasing
environmental issues [3]. It is obvious there is an urgent need to change the current situation with
the need to search for energy alternatives involving locally available renewable resources.
Biomass which is the fourth largest energy source after coal, oil and natural gas is currently the
most important renewable energy option for now [4]. Commercial biomass can be used to provide
heat and electricity as well as liquid bio-fuels and biogas for transport. Although there are risks
related to such factors as supply, fuel quality, and price increases, as well as issues such as
competition for land area and the degree of renewability of given resources. Sustainability reduces
such risks, and can be supported by certification of substrates’ origin [5].
Bio-energy is attractive at all stages of development due to its potential integration with all
possible development strategies worldwide. The potential of bio-energy is widely recognized and
it offers opportunities to address questions other than energy. Thus, it can be a solution for matters
relating to economic, national, environmental and political security [6]. Moreover, bio-energy is
based on resources that can be utilized on a sustainable basis all around the globe and can provide
an effective option for the provision of energy services from a technical perspective. In addition,
the benefits accrued go beyond energy provision, creating unique opportunities for regional
development [7].
Biodiesel is a carbon-neutral liquid fuel made through trans-esterification reaction of altering the
chemical properties of vegetable oils and fats using alcohol [8]. This simple process yields high
conversion with glycerin as the only byproduct. It’s very similar to petroleum diesel, but not
identical. However, the difference is remarkably small when we compare the procedure for
making biodiesel and petroleum diesel [9].
Neem seed oil is obtained from Neem plant Azadirachta indica derived from Persia, popularly
known in Nigeria as Dongonyaro. The tree is a native of South East Asia and is a member of the
Mahogany family Meliaceae. Also, large volumes of Neem seeds are generated in Nigeria as well
as other countries which could be a possible nuisance in our rural and urban areas. Although, other
oils can also be used for biodiesel production, but that extracted from Neem seeds is chosen
because the seeds are readily available and not edible therefore, will not pose problem to humans
in terms of food consumption, competition, security and also solve the challenge of pollution,
management and treatment [10].
However, many researchers have analysed the nutritional and pharmaceutical values of the oil but
search of the literature has shown that little information exist about the oil as a feedstock for
producing and characterising biodiesel.
2. Methodology
2.1 Sample Collection

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Neem seed (Azadirachta indica) were collected from the botanical garden of the University of
Ibadan, Ibadan in Oyo State, Nigeria. It was identified according to the flora of West Africa in the
Herbarium Unit of University of Ibadan where vouchers of each specimen were deposited.
2.2 Sample Preparation
The Neem seeds were sun-dried and the shells were manually cracked to obtain the kernels. The
kernels were then milled and stored at 4oC until needed for analysis.
2.3. Oil Extraction
Oils from the milled seeds was exhaustively extracted with a Soxhlet apparatus using methanol as
the solvent after which it was subjected to physico-chemical characterization using standard
analytical methods on the appearance, water and sediment, viscosity, specific gravity, density,
colour, pH, sulphur, acid and FFA values, total,free and bound glycerine, flash, pour and cloud
points, cetane number, saponification, iodine and peroxide values, molecular weight using
A.O.A.C. (2000) and A.O.C.S. (2003).
2.4. Biodiesel Production
The oil was heated in an oven at 100-120 C⁰ for 20 min to reduce moisture/water concentration
below 5 g/kg. The mechanism of reduction in free fatty acid was adopted for oils containing FFA
up to 20%, by lowering the acid value, making 300 cm3 of oil used to contain FFA less than 1%.
This is done by adding sufficient potassium hydroxide in 700 g/L aqueous solution, heated at 30-
35 C to precipitate the solids and allowed to settle overnight, then the clear oil was decanted and⁰
the FFA determined according to ISO EN660, 1996.
The step by step approach used in the production of biodiesel during transesterification are;
(i) Measurement and heating of 300 cm3 of oil sample to a temperature of 60°C
(ii) Purification and measurement of 1800 cm3 methanol to be used by re-distillation
(iii) Preparation and addition of the 1.0% potassium methoxide solution into the warm oil sample
(iv) Separation of the biodiesel from the lower layer (which comprises glycerol and soap)
(v) Washing of the biodiesel to remove any excess glycerol and soap that may remain
(vi) Drying of the washed biodiesel sample to remove excess methanol
(vii) Measuring, analysing and recording of the quantity and quality of the biodiesel produced.
The measuring of ratio 1:6 oil to methanol, 1.0% catalyst concentration, stirring time for 2 hrs at
400 rpm, and the temperature at 60°C [14].
2.5. Characterizations of the Oil and Biodiesel
Standard procedures according to the American Oil Chemists’ Society [11, 15], Official Methods
of the American Oil Chemists’ Society [12] and American Society for Testing and Materials
(ASTM) methods of analysis were adopted in the characterization of the raw oil and the biodiesel
produced. 2.5.1. Percentage yield
The percentage yield of the oil was calculated using Equation 1 [16]
Percentage yield =
Volume of samle extract
Weight of sample taken x100
(1) 2.5.2. Appearance
A physical eye check was carried on the sample.
2.5.3. Water and Sediment content
Sample of 5 g thoroughly mixed by stirring was weighed into a previously dried
and weighed crucible with lid. The crucible without the lid was heated in an oven set at 105±1 C⁰
for 1 hr. The crucible plus the sample was removed from the oven and covered with the lid and
then cooled in a desiccator containing phosphorus pentoxide and weighed. It was later heated in
the oven again for a further period of 1 hr, cooled and weighed. This process was repeated five
times until change in weight between two successive observations was not noticed [11].

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% Water and Sediment content =
Sample loss of weight on drying
Weight of sample taken x100
(2) 2.5.4. Viscosity
Viscosity of the samples was measured at room temperature (in
centistokes) with the Oswald kinematic viscometer equipped with an attached water bath and a
thermostat [12]. 2.5.5. Specific gravity
The specific gravity of the oil extracted and biodiesel were
determined by means of a pyconometer [15].
2.5.6. Density
This was determined from specific gravity using Equation 3;
Density of sample = Specific gravity x Density of water
(3) Where density of water is 1 g/mol [11]
2.5.7. Colour
The colour of the oil extracted and the diesel were determined by
comparison with Lovibond glasses of known colour characteristics, and the colour was expressed
as the sum total of the yellow and red slides used to match the colour of the diesel in a cell of the
specified size in the Lovibond Tintometer [11].
2.5.8. pH, sulphur and carbon contents
These parameters of the extracted oil and diesel were determined according to the method
described in the American Oil Chemists Society [12] official and tentative methods [17,18].
2.5.9. Acid value
The acid value of the samples was determined by titrating the oils and the diesel in an alcoholic
medium against standard NaOH solution [17].
2.5.10. Free fatty acid
The free fatty acid in the samples was determined by titrating each sample against potassium
hydroxide using phenolphthalein as indicator [17].
2.5.11. Total, free and bound glycerine
Sample of 1 g each was measured into a 250 cm3 volumetric flask and 25 cm3 chloroform-
methanol mixtures were added to dissolve the sample. About 10 cm3 of silisic acid and 10 cm3
alcoholic KOH were added to precipitate the glycerine. The supernatant obtained was decanted
and the precipitate was dissolved in 10 cm3 of 0.2 M H2SO4 followed by the addition of 20 cm3
0.05 M sodium metaperiodate and 5 cm3 of sodium arsenite. The mixture was properly
homogenised to get a uniform solution containing the total glycerine. Glycerine working standard
of the range of 10 to 50 µg/cm3 were prepared from 100 µg/cm3 stock glycerine and treated
similarly as sample above. The absorbance of the samples and working standards were taken on a
UV Spectrophotometer at a wavelength of 560 nm [12].
Total glycerine (GT) =
Absorbance x Gradient Factor x Df
Weight of sample x 10,000
(4) Free glycerine was obtained by titrating the dissolved precipitate against 0.0
M Na2S2O3 using starch solution as indicator.
Free glycerine (GF) =
(
Blank titre – Sample titre
)
x M of Na 2S2O3x7.638
Weight of sample used
(5) Bound
glycerine was calculated using the equation; Bound
glycerine = Total glycerine - Bound glycerine (6) 2.5.12.
Flash point This
was done by determining the temperature at which the sample flashed when a test flame is applied
under the conditions specified for the test [11]. 2.5.13.

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Pour point The
pour point of the samples was determined by cooling the sample at a specified rate and the
samples examined at 3ºC intervals for flow characteristics. The lowest temperature at which
samples movement was observed was then noted as the pour point [18].
2.5.14. Cloud point
The temperature at which a cloud is induced in the sample by cooling at a specified rate and
examined at 3oC for first stage crystallization was determined according to A.O.C.S. (2000).
2.5.15 Cetane number
ASTM D613-18a (2008). Standard test method for cetane number of diesel fuel oil was used to
determine the cetane number of the samples.
2.5.16. Saponification value
The samples were saponified by refluxing with excess alcoholic KOH solution. The alkali
required for the saponification was determined by titration of the excess KOH with standard HCl
[11].
2.5.17. Iodine value
Sample of 0.25 g was taken into carbon tetrachloride and treated with excess iodine monochloride
solution in glacial acetic acid (Wijs solution). The excess of the iodine monochloride was then
treated with potassium iodide and the liberated iodine was estimated by titration with sodium
thiosulphate solution [11].
2.5.18. Peroxide value
The peroxide present was determined by titrating the sample against sodium thiosulphate solution
in the presence of KI using starch as indicator [14].
2.5.19. Molecular weight
Saponification and acid values were first determined and then the molecular weight was calculated
using Equation 7;
Mwt =
168300
SV −Av
(7)
Mwt is the molecular weight, SV is the saponification value, Av is the acid value and
168300 is the Constant [19].
2.5.20. Wet digestion
Sample of 1.0 g of each (oven dried at 60 C) was weighed into a 125 cm⁰3 Erlemeyer flask
previously washed with acid and distilled water. Perchloric acid of 4 cm3, 25 cm3 concentrated
HNO3 and 2 cm3 concentrated H2SO4 under a fume hood were added. The contents were mixed
and heated gently at 120 C on a hot plate under perchloric acid in a fume hood and heating⁰
continued until dense white fumes appear. Presence of any traces of carbon remain, then the flask
was allowed to cool and added 2 cm3 concentrated HNO3, digested again to the fuming stage and
finally, heated strongly at 150 to 240 C for half a minute. It was allowed to cool and added 50⁰
cm3 distilled water then boiled for half a minute on the same plate at a 150 C. The solution was⁰
cooled and filtered completely with Whatman No. 42 filter paper, then made up to 100 cm3 mark
in Pyrex volumetric flask with distilled water. The solution was analysed for Aluminium by
Atomic Absorption Spectrometry and Potassium by Flame Emission Spectrometry at each
wavelength of maximum absorption and emission.
2.6. Statistical analysis
Results obtained were expressed as the mean of three separate observations. The data was
statistically analyzed with 2-way analysis of variance (ANOVA) using SAS software. The means
were compared by Duncan’s Multiple Range Test at 5% level of significance (p≤0.05).
3. Results and Discussion
Table 1.0: Physico-chemical properties of Neem seed oil and it’s Biodiesel (B100)

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Parameters Neem seed oil
extract
Neem seed oil
Biodiesel
PD/BD ASTM,
2008B, 2011
/EN, 2009, 2010
Standard

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Appearance Golden yellow
viscous liquid
Light golden yellow
viscous liquid
Varies
Yield (%) 41.5 80.9 96.5 min
pH 6.10 6.69 Varies
Viscosity ( mm2/s at 40 C)⁰31.99±0.20 4.99±0.10 1.9-6.0
Specific gravity (g/g) 0.92±0.01 0.90±0.00 0.88
Density (g/cm3)0.91±0.00 0.89±0.00 <0.86
Water and sediment (%) 1.82±0.20 0.95±0.01 0.05
Colour (Hz) 4.15±0.30 3.55±0.20 ≤4.00
Flash point (oC) 192.70±2.00 157.52±1.00 93.0 min
Pour point (oC) 11.00±0.10 8.30±0.20 -15 to10
Cloud point (oC) 15.00±0.20 10.20±0.40 -3 to 12
Cetane Number 49.20 53.75 47 min
Acid value (mgKOH/g) 20.90±0.30 9.60±0.02 0.50 max
Free fatty acid (mgKOH/g) 10.45±0.20 4.80±0.01 0.25 max
Total Glycerin (%) 0.25±0.03 0.15±0.02 0.24
Bound Glycerin (%) 0.16±0.02 0.10±0.01 0.24
Free Glycerin (%) 0.09±0.01 0.05±0.00 0.02
Iodine value (g/100g) 76.50±0.30 60.93±0.20 120 max
Saponification value (mgKOH/g) 196.89±0.04 178.45±0.30 NA
Peroxide value (mEq/kg) 8.15±0.10 5.75±0.02 10-20 (Oil)
Carbon residue (%) 0.22±0.02 0.16±0.01 0.05 max
Molecular weight (g/mole) 315.50 289.30 Varies
Sulphur (mg/kg) 7.30±0.30 4.80±0.02 10 max
K (mg/kg) 0.05±0.00 0.02±0.00 0.01-0.20
Al (mg/kg) 0.33±0.10 0.28±0.02 0.50
3.1. Physico-chemical properties
Table 1.0 shows the physico-chemical properties of Neem seed oil and it’s biodiesel (B100), with
the appearance of the samples being similar. The appearance of Neem seed oil was golden yellow
liquid but Dangarembizi et al. (2015) had yellow green solid oil. The appearance of Need oil
biodiesel was light golden yellow liquid but Ibikunle et al. (2019) had golden viscous liquid in
both the oil and biodiesel produced. Appearance varies in ASTM/EN limit because the difference
in chemical component of samples is responsible for this observation [27].
The yield of Neem seed oil of 41.5% is much higher than that of Dangarembizi et al. (2015) who
obtained 9.53%, Neem seed oil biodiesel yield was 80.9% which is lower than ASTM, 2011/EN,
2010 standard of 96.5% min. The oil yield is dependent on the physico-chemical composition,
oil:solvent ratio and type, temperature and time while that of the biodiesel also includes these with
catalyst type and concentration, stirring speed, transesterfication type, separation and washing
methods involved [28].
pH of Neem seed oil was 6.10, which is slightly acidic and shows that the oil requires pre-
treatment to reduce the acidity so as to make it suitable for biodiesel production. Neem seed
biodiesel pH was 6.69, tending neutral but differs in ASTM/EN standard.
The viscosity of Neem seed oil was 31.99±0.20 mm2/s at 40oC, Neem seed oil biodiesel was
4.99±0.10 mm2/s at 40oC was lower than the oil due to transesterification reaction, but within
ASTM, (2008)/EN, (2009) standard of 1.90-6.00 mm2/s at 40oC. The Neem seed oil biodiesel
value is lower than those of Aransiola et al. (2011), Taiwo et al. (2016) and De Lima da Silva et
al. (2009). Less viscosity gives greater ease of fuel movement for better and faster fuel
atomization and decrease in ignition delay.
Specific gravity and density of Neem seed oil were 0.92±0.01 g/g and 0.91±0.00 g/cm3
respectively. The high values are because the weight is heavy due to some impurities that might be
present which calls for pre-treatment of the oil to make them biodiesel production suitable (Moser,

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2(2) 2020 pp. 178 - 187
2009). Those of Neem seed oil biodiesel was 0.90±0.00 g/g and 0.89±0.00 g/cm3 respectively,
which are lower than those of the oil due to trans-esterification process but higher than ASTM,
(2008b) standard of <0.88 g/g and <0.86 g/cm3 respectively. The density value is also higher than
that of Ali et al. (2013) of 0.88 g/cm3 and 0.61 g/ cm3 for Neem seed oil and biodiesel respectively.
The specific gravity value of biodiesel is less than that of Aransiola et al. (2011) but density value
is lower than that of De Lima da Silva et al. (2009). High values could be because the weight is
heavy due to some Impurities that might be present [32]. Density influences the air-fuel ratio due
to mass of the oil and the biodiesel. The water and
sediment was 1.82±0.20 % in Neem seed oil, which is higher than 0.95±0.01 % in Neem seed oil
biodiesel thus it needs pre-treatment of heating, filtration to make it suitable for transesterification
reaction. The biodiesel value is above 0.05 % ASTM, (2008)/EN, (2009) standards. The value is
lower than that of Taiwo et al. (2016) but higher than that of De Lima da Silva et al. (2009). Water
and sediments are byproducts of storage due to ester oxidation, reactive glycerides and algae
growth.
The colour value of the Neem seed oil was 4.15±0.30 Hz which is higher than that of Neem seed
oil biodiesel (3.55±0.20 Hz) but within permissible ASTM/EN standard of ≤ 4.00 Hz. Colour
value of the biodiesel is less than that of Taiwo et al. (2016). The difference in chemical
component of samples could be responsible for the variations observed [27].
The flash point of Neem seed oil was 192.70±2.00oC which is higher than that of Neem seed oil
biodiesel (157.52±1.00oC), but within the permissible standard of 93.0oC max of ASTM, 2011/EN,
2010. The value is higher than values were reported by Tyson, (2001), De Lima da Silva et al.
(2009) (93oC). Flash point is the safety requirements in handling and storage of fuel due to its
hazardous nature and biodiesel is safer than petroleum diesel due to high values.
Pour point is the lowest temperature at which biodiesel can still move. Neem seed oil value was
11.00±0.10oC, which is higher than that of Neem seed oil biodiesel (8.30±0.20oC), with both
within ASTM, 2011/EN, 2010 of -15 to 10, which shows that the biodiesel except the oil will not
perform better due to the presence of saturated fatty acid chains and monoglycerides [35]. The
pour point value was greater than that of Aransiola et al. (2011) and Taiwo et al. (2016).
Cloud point is an important parameter for low temperature operation of fuel due to solidification
of heavier components in biodiesel resulting in crystals within the body when cooled. Neem seed
oil value was 15.00±0.20oC, which is higher than that of Neem seed oil biodiesel (10.20±0.40oC)
but above ASTM, 2011/ EN, 2010 of -3 to 12 oC. This also shows that the oil will perform better in
low temperature than the biodiesel. The cloud point values were greater than that of Aransiola et
al. (2011) and Taiwo et al. (2016).
Cetane number of Neem seed oil was 49.20 which was lower than that of Neem seed oil biodiesel
(53.75), but within ASTM, 2011/EN, 2010 standard of 47.00 min and higher than that of De Lima
da Silva et al. (2009) (50.00). Cetane number is critical in cold starting engine conditions because
low values results in long ignition delay and high in faster auto-ignition [36].
Free fatty acid and acid values of the Neem seed oil was 10.45±0.20 mgKOH/g and 20.90±0.30
mgKOH/g which is more than double that of Neem seed oil biodiesel of 4.80 ±0.01 mgKOH/g and
9.60±0.02 mgKOH/g. This necessitates the pre-treatment of the oil for reduction in acidity by
addition of excess KOH to enhance biodiesel process and production. The biodiesel value is above
the ASTM, (2011)/EN, (2010) standard of 0.25 to 0.50 mg/KOH/g which calls for further
treatment to reduce the acidity to permissible limit. Also the values are less than those of Aransiola
et al. (2011) and Taiwo et al. (2016) but higher than that of Ibikunle et al. (2019). Acid value is the
level of residual organic acids due to oxidation leading to deterioration.

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Total and bound glycerine values in Neem seed oil was 0.25±0.03% and 0.16±0.02%, which was
higher than that of Neem seed oil biodiesel (0.15±0.02% to 0.10±0.01%), with all the values
within the ASTM, 2011/EN, 2010 standard of 0.24% which is an indication of more complete
trans-esterification process in biodiesel production. The total and bound glycerine values were
greater than those of Aransiola et al. (2011) and Taiwo et al. (2016).
Free glycerine values in Neem seed oil was 0.09±0.01% which was higher than that of Neem seed
oil biodiesel (0.05±0.00%), but all was above the permissible standard of 0.02%.
Iodine value of Neem seed oil was 76.50±0.30 gI2/100g which is higher than of Dangarembizi et
al. (2015) and Neem seed oil biodiesel of 60.93±0.20 gI2/100g, but all were within the ASTM,
2011/EN, 2010 Standard of 120 gI2/100g max. Iodine value is less than those of Aransiola et al.
(2011), Taiwo et al. (2016) and De Lima da Silva et al. (2009) but higher than that of Ibikunle et
al. (2019). Low value could be as a result of the destruction of double bonds and vice versa, high
values results in propensity for polymerization leading to deposit formation [36].
Saponification value of Neem seed oil was 196.89±0.04 mgKOH/g, which was lower than that
obtained by Dangarembizi et al. (2015) but higher than those of Neem seed oil biodiesel
(178.45±0.30 mgKOH/g). The value was close to that of Aransiola et al. (2011), but lower than
those of Reed et al. (1994) (155.50 to 159.70 mgKOH/g). The variation in the saponification value
shows the differences in chain lengths of the free fatty acids present the samples. Long chain fatty
acids found in fat and oil have low saponification value because they have a relatively fewer
number of carboxylic functional groups per unit mass, therefore has high molecular weight [38].
Standard saponification values for biodiesel are not stated but all values observed were within the
standard value for oil of 192-198 mgKOH/g.
The peroxide value of the Neem seed oil was 8.15±0.10 mEq/kg, which is higher than those of
Neem seed oil biodiesel (5.75±0.02 mEq/kg) showing good quality status in the biodiesel.
Standard peroxide values for biodiesel are not stated but all values observed were within the
standard value for oil samples of 10-20 mEq/kg but 30-40 mEq/kg are associated with a rancid
taste [39]. The variation in the values shows the extent deterioration has advanced in the samples
and this is used for identifying the onset of oxidative change during which the oxygen (O2)
molecule penetrates the molecule in the form of a peroxide group (H2O2) [36]. This also is the
amount of unstable hydroperoxides (deteriorated biodiesel) when oxygen reacts with fatty esters.
Carbon residue in Neem seed oil was 0.22±0.02%, which is higher than that of Neem seed oil
biodiesel (0.16±0.01%), but above the permissible limit of 0.05% max of ASTM, 2011/EN, 2010.
Higher values indicate the presence of higher organic particles in the sample which could lower
the reaction [40].
Molecular weight of Neem seed oil 375.50 g/mole, which is higher than that in Neem seed oil
biodiesel (289.30 g/mole) but differs in ASTM/EN standards because of its dependence on the free
fatty acid present coupled with the saponification value. Transesterification of vegetable oil
reduces the molecular weight and viscosity of the oil, and improve its volatility to a suitable range
for diesel engines [41].
Sulphur in Neem seed oil was 7.30±0.30 mg/kg, which is higher than that of Neem seed oil
biodiesel (4.80±0.02%), but with all above ASTM, 2011/EN, 2010 permissible limit of 10.0 mg/kg
max. Potassium in Neem seed oil was 0.05±0.00 mg/kg which is lower than that of Neem seed oil
biodiesel (0.02±0.00 mg/kg), but all are within limit of 0.01-0.20 mg/kg. Aluminium in Neem seed
oil was 0.33±0.10 mg/kg which is higher than that of Neem seed oil biodiesel (0.28±0.02 mg/kg),
but within ASTM, (2008)/EN, (2009) standard of 0.50 mg/kg and less than that of Taiwo et al.
(2016). This indicates the safety and rate of reduction in degradation because metals initiate
spoilage that affects shelf-life stability of the samples and also their bio-accumulation in the body
over time can lead to serious harmful effect and health risk.

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4. Conclusion
There seems to be no danger in terms of neem seed reserves and potential capacity for future
sustainability since its going be part of the substitute for biodiesel production and could also be
blended with flammable solvents so no total dependence on it.
The physico-chemical and fuel properties characterized have most values within the ASTM,
(2008)/EN, (2009) standards except in the Neem seed oil. The Neem seed oil can be used for
biodiesel production after pre-treatment to reduce the concentration of some of the parameters that
are above permissible limits and it can also be used in soap production.
Neem seed oil biodiesel can be a major contributor now and thereafter in the future by meeting the
demand expected of petroleum diesel. Finally, also based on these fuel properties, it can used with
little or no modification on diesel engines and plants.
5. Acknowledgements
The authors acknowledge the grant from TETFUND, Nigeria through the Management of
Moshood Abiola Polytechnic and administered by the Directorate of Research and Development to
carry out this laudable research in alternative renewable energy.
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