Page 129 - Advances in Eco-Fuels for a Sustainable Environment

Prospective ecofuel feedstocks for sustainable production 101

oil are palmitic acid (34wt%), stearic acid (7wt%), oleic acid (9wt%), and linoleic
acid (44wt%) [12]. As per the work carried out by Liu et al. [45], coffee oil conversion
to coffee oil biodiesel obtained has been around 98.61% at 70°C in a reaction time
of 12h with 20% sulfuric acid. Some of the properties displayed by the methyl esters
2
of coffee oil include a kinematic viscosity of 5.27–7.36mm /s and an acid value of
0.80mgKOH/g [45].

Desert date oil (Balanites aegyptica)
The desert date tree (Balanites aegyptiaca L. Delile) belongs to the family Zygo-
phyllaceae, and it is highly adapted to drier parts of South Asia and Africa. It is dis-
tributed in the most adverse and desert environments. The trees grow to a height of
10m. The desert date fruit consists of epicarp, mesocarp or pulp, endocarp, and a ker-
nel and the fruit weighs about 5–8g. Approximately 50wt% of oil content is present in
the desert date fruit kernel [46]. The fatty acid profile of desert date oil shows that it
has a high quantity of linoleic acid (31.5wt%) and other fatty acids such as oleic acid
(43.7wt%), palmitic acid (13.7wt%), and stearic acid (11.0wt%) are present in mod-
erate quantities. Other fatty acids such as myristic acid, pentadecanoic acid, pal-
mitoleic acid, etc., are present in meager quantities [17]. Chapagain et al. [46]
reported the maximum conversion of desert date oil to biodiesel obtained has been
around 90% for a methanol to oil ratio of 6:1 in a reaction time of 1h with 1.7%
(wt of oil) KOH as a catalyst. Some of the properties exhibited by fatty acid methyl
2
esters of desert date oil include a kinematic viscosity of 3.7–4.2mm /s, a cetane num-
ber of 53.56, and a cloud point of 3–7°C [46].

Castanhola oil (Terminalia catappa)
Castanhola is the common name in Brazil for Terminalia catappa. It grows to 35m in
height and belongs to the Combretaceae family. Throughout the tropics in Asia and
South America, this plant is widely distributed. Several species of genus Terminalia
have been used as traditional medicine to treat infectious diseases in both east and west
African countries [47]. The free fatty acid content in T. Catappa is relatively low
(0.5wt%).ThedominantfattyacidsinT.catappaseedsarepalmiticacid(35.0wt%),oleic
acid (32.0wt%) and linoleic acid (28.0wt%) whereas stearic acid (5wt%) is present in
low quantity [48]. As per dos Santos et al. [48], a fatty acid methyl ester yield of 93%
has been obtained from Castanhola oil with a methanol to oil ratio of 6:1 at a reaction
temperature of 60°C using catalysts such as NaOH and CH 3 CH 2 ONa. Some of the prop-
2
erties displayed by Castanhola oil biodiesel include a kinematic viscosity of 4.3mm /s
and calorific value of 36.97 (MJ/kg) [48].
Milkweed seed oil (Asclepias syriaca)
Common milkweed (Asclepias syriaca) is native to the northeast and the north-central
United States and belongs to the family Asclepiadaceae. It is a perennial plant that
produces a marketable fiber with unusual thermal properties and is generally consid-
ered a nuisance by farmers. The oil content of dried milkweed seed is 20–25wt% [49].
It is mainly composed of unsaturated fatty acids such as linoleic acid (48.7wt%), oleic