Environmental Engineering Reference
In-Depth Information
larger and more complex terpenes (e.g. aqualene and lanosterol) occur in an-
imals. Terpenes typically have very strong odors in low concentrations. Many
terpenes are hydrocarbons, but oxygen-containing compounds such as al-
cohols, aldehydes, ketones, acids, esters and epoxides (terpeneoids) are also
found. Their building block is a hydrocarbon, i.e., isoprene. Terpene hydro-
carbons therefore are expressed by a molecular formula: (C
5
H
8
)
n
,andthey
areclassifiedaccordingtothenumberofisopreneunits:monoterpenes(num-
ber of isoprene units is two:
n
= 2), sesquiterpenes (
n
= 3), diterpenes (
n
=4),
sesterterpenes (
n
= 5), triterpenes (
n
= 6) and tetraterpenes (
n
=8). Some
steroids are also classified into triterpenes. Terpenes are considered to be
biodegrable. Many of these terpenes are biologically active substances such
Scheme 1
