Chemistry Reference
In-Depth Information
Among bio-based products from agricultural resources, such as plant oils,
polysaccharides (mainly cellulose and starch), sugars, wood, and others,
plant oils make up the greatest portion of the current consumption of re-
newable raw materials in the chemical industry. Plant oils are non-toxic, bio-
degradable, non-polluting, and relatively harmless to the environment. In
addition to the above-mentioned advantages, plant oils are liquids at room
temperature and can be chemically modified because of their excellent
solubility in most reaction media. Approximately 80% of the global fat
production is vegetable oil, and 20% is of animal origin (share decreasing).
3
In 2009, soybean accounted for about 23.4% of planted acreage in the USA,
just behind corn, which accounts for about 26.1%, and ahead of wheat,
which accounts for about 18.0%. About three billion bushels of soybean are
grown annually in the USA, of which the current market demand is about
2.9 billion. Developing new uses for surplus soybean oil (SBO) is important
to prevent price depression due to oversupply.
SBO has a rich history of use as mechanical lubricants and soaps, ranging
from ancient times in East Asia to paints, fuel and biodiesel currently
worldwide. The most recent large-scale industrialized use of SBO and other
vegetable oils is in the area of alternative fuels for diesel engines. Polymeric
materials prepared from vegetable oils have become increasingly important
because of their low cost, readily availability and bio-degradability. Polymer-
ized SBOs have been employed in printing inks and paints.
4,5
Nowadays, there
is a growing interest in producing various green materials from plant oils. For
example, polyurethanes from vegetable-oil-based polyols have been widely
studied by the Petrovi
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group and others.
6,7
Since the start of the decline in
petroleum supplies, preparation of polymers from renewable sources has be-
come more important due to their attractive properties, such as bio-degrad-
ability and, in some cases, they are cheaper than petroleum polymers.
Particularly, in the USA, SBO is one of the most abundant renewable resources.
SBO is a triglycerol with saturated and unsaturated fatty acids, 80-85%
being unsaturated fatty acids. SBO has around 4.6 double bonds from oleic
(C18:1), linoleic (C18:2) and linolenic (C18:3) acids, as shown in Figure 3.1.
Unfortunately, the internal 1,2-disubstituted non-conjugated double bonds
are of low reactivity and polymerize with diculty.
6
However, these double
bonds may be converted into more reactive oxirane (or epoxide) moieties
by reaction with peracids or peroxides. Epoxidized soybean oil (ESO) used
as a raw material for the synthesis of new polymers has been reported by
our group.
8,9
Figure 3.2 shows the structure of ESO. Euphorbia oil (EuO) is
O
Glycerol
Fatty acid chain
O
O
O
O
O
0-3 Double bonds
12-22 Carbons long
Figure 3.1 The structure of soybean oil (SBO).
