Page 140 - Biofuels Refining and Performance

Raw Materials to Produce Low-Cost Biodiesel 123

Its fatty acid composition includes palmitic acid (10.2%), stearic acid
(8.7%), oleic acid (24.6%), linoleic acid (39.6%), and linolenic acid
(16.3%) [118].

Main uses. The crop is of major economical importance because it pro-
duces latex. The wood from this tree is used in the manufacture of high-
end furniture. In Cambodia and other rubber-manufacturing countries,
rubber seeds are used to feed livestock. Rubber seed contains cyanogenic
glycosides that will release prussic acid in the presence of enzymes or
in slightly acidic conditions. Press cake or extracted meal can be cau-
tiously used as fertilizer or feed for stock [119].
Several studies to check its feasibility as a source of biodiesel have
been undertaken. Ikwuagwu et al. have prepared methyl esters of
rubber seed oil using excess of methanol (6 M) containing 1% NaOH
as a catalyst. Petroleum ether was added to the reaction to produce
two phases. Analysis of the properties have shown a good potential for
use as an alternative diesel fuel, with the exception of the oxidative
stability [120]. Ramadhas et al. have performed a previously acid-
catalyzed esterification to reduce the high FFA content, followed by an
alkaline esterification. Sulfuric acid 0.5% by volume and a methanol-
oil molar ratio of 6:1 was used in the pretreatment. A molar ratio of
9:1 and 0.5% by weight of sodium hydroxide was used during the
second step. The authors found a reduction in exhaust gas emissions.
The lower blends of biodiesel increased brake thermal efficiency and
reduced fuel consumption [121].

4.2.12 Tonka bean oil
Crop description. Dipteryx odorata—commonly known as sarapia, tonka
bean, amburana, aumana, yape, charapilla, and cumaru—belongs to the
family Leguminacea and grows in tropical areas (see Fig. 4.13). Major
producing countries are Guianas and Venezuela. The tonka bean is the
seed of a large tree. The kernel contains up to 46% oil on a dry basis.
Major fatty acid composition of oil includes palmitic acid (6.1%), stearic
acid (5.7%), oleic acid (59.6%), and linoleic acid (51.4%) [77].

Main uses. The oil is used in perfumery and as a flavoring material.
Tonka extracts are used in the tobacco industry to impart a particular
aroma. Few attempts have been made to use it as a raw material to pro-
duce biodiesel. Abreu et al. conducted methanolysis of cumaru oil using
different homogeneous metal (Sn, Pb, and Zn) complexes as catalysts.
They found that pyrone complexes of different metals are active for
cumaru-oil transesterification reaction [122].