Environmental Engineering Reference
In-Depth Information
Dichloromethane
C1
2
CH
2
Trichloromethane (chloroform)
Cl
3
CH
Tetrachloromethane (carbon tetrachloride) C1
4
C
Dichlorodifluoromethane (a CFC)
a
C1
2
CF
2
1,2-Dichloroethane
1,2-Dichloroethene
Freons
a
(used as refrigerants)
Trichloroethylene
Vinyl chloride (monomer used in the production of plastics)
a
Numbers of chlorines and fluorines varies in chlorofluorocarbons (CFCs).
Note:
Most of these compounds are used as solvents.
nas
and
Bacillus,
the actinomycetes
Streptomyces
and
Saccarothrix,
and the fungi
Aspergillus
and
Penicillium
. It thus cannot be assumed that all halogenated organic
compounds are anthropogenic, nor can it be assumed that all halogenated organic
compounds are resistant to degradation in the environment [21].
9.3.2.
Aromatic Compounds
Another group of compounds with the characteristics of hydrocarbons are those
containing benzene rings. Another name for these hydrocarbons is aromatic, although
they often do not have a sweet or spicy fragrance. Many aromatic compounds are of
environmental concern as toxins or carcinogens; however, an equal or greater number of
compounds containing benzene rings are inert or even beneficial. Tryosine, an amino
acid, cinnamonaldehyde, a component of cinnamon responsible for its smell and taste,
and aspirin, an analgesic, are but three benzene ring-containing compounds regularly
used by humans. Phenylalanine, another amino acid that contains a benzene ring, is an
essential dietary amino acid.
Compounds containing a benzene ring can be classified as belonging to one of three
groups. A relatively simple group is those compounds that contain only one benzene ring
having some group attached to it. Examples are the benzene itself, along with toluene,
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