Chapter 2: Essential Oil Organic Chemistry
Chemists use special diagrams called Lewis structures to map
out the detailed structure of a molecule. For example, figure 2.1 is
a Lewis structure depicting the essential oil constituent limonene.
The letters in this diagram represent atoms. “C” stands for carbon,
and “H” stands
for hydrogen. The
lines
represent
chemical bonds
between atoms
and the double
lines
represent
double
bonds.
Notice how the
molecule’s shape
Figure 2.2: Carbon skeleton
is
determined
diagram of limonene. Note
by the carbon
that H’s and C’s are not
Figure 2.1: Lewis structure
shown, greatly simplifying
of
limonene.
Note
the
backbone.
You
the diagram.
complexity of the diagram.
may have also
noticed how complicated the diagram is. A more compact way
to depict the backbone structure is by using a carbon skeleton
diagram (figure 2.2). Because of their simplicity, carbon skeleton
diagrams are the most commonly used chemical diagrams for
depicting organic molecules.
Carbon skeleton diagrams show the structure of an organic
compound in a similar fashion to Lewis structures, but there are a few
key differences. Take a moment to look at the differences between
figure 2.1 and figure 2.2. In the skeleton diagram, hydrogens are left
out and the carbons are not labeled. Since the bonds are still shown,
you can tell where the carbons are because they exist at either end
of a line representing a bond.
Terpenes are the class of aromatic molecules synthesized by
plants. Every plant has hundreds of special enzymes called terpene
synthases that work together to build these compounds out of smaller
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