General Description
White to off-white crystals.
Reactivity Profile
Can react vigorously with oxidizing materials. .
Air & Water Reactions
Insoluble in water.
Fire Hazard
This chemical is combustible.
Description
Trichlorobenzenes (TCBs) are synthetic chemicals that
occur in three different isomeric forms. The three chlorinated
cyclic aromatic isomers are 1,2,3-trichlorobenzene (1,2,3-TCB),
1,2,4-trichlorobenzene (1,2,4-TCB), and 1,3,5-trichlorobenzene
(1,3,5-TCB). 1,2,4-TCB is one of the 188 chemicals designated
as a hazardous air pollutant under the Clean Air Act.
Chemical Properties
white to beige crystalline powder
Uses
1,3,5-Trichlorobenzene is used for someof these
applications plus as a termite preparation and insecticide.
These compounds are found as unintended by-products of
the manufacture of the mono- and dichlorobenzenes.
Uses
Trichlorobenzenes are primarily used as solvents in chemical
manufacturing industries. 1,2,4-Trichlorobenzene is economically
the most important isomer. 1,2,4-Trichlorobenzene is
used as a solvent in chemical reactions to dissolve oils, waxes,
and resins. Furthermore, it is also used as a dye carrier. 1,2,3-
Trichlorobenzene is used as an intermediate for pesticides
production, pigments, and dyes. 1,3,5-Trichlorobenzene is not
marketed commercially and has very limited use as a chemical
intermediate. Besides, trichlorobenzenes can also be used as
degreasing agents, as septic tanks and drain cleaners, and as an
ingredient in wood preservatives and abrasive formulations.
Other minor uses include metal work, anticorrosive paint, and
corrosion inhibitor in sprays. In the past, mixed isomers of
trichlorobenzenes were used to control termites; however, their
use has been discontinued.
Definition
ChEBI: 1,3,5-trichlorobenzene is a trichlorobenzene carrying chloro substituents at positions 1, 3 and 5.
Environmental Fate
Biological. Under aerobic conditions, soil microbes degraded 1,3,5-trichlorobenzene to 1,3- and
1,4-dichlorobenzene and carbon dioxide (Kobayashi and Rittman, 1982). A mixed culture of soil
bacteria or a Pseudomonas sp. transformed 1,3,5-trichlorobenzene to 2,4,6-trichlorophenol
(Ballschiter and Scholz, 1980).
In an enrichment culture derived from a contaminated site in Bayou d’Inde, LA, 1,3,5-
trichlorobenzene underwent reductive dechlorination yielding 1,3-dichlorobenzene. The maximum
dechlorination rate, based on the recommended Michaelis-Menten model, was 9.5 nM/d
(Pavlostathis and Prytula, 2000).
Photolytic. The sunlight irradiation of 1,3,5-trichlorobenzene (20 g) in a 100-mL borosilicate
glass-stoppered Erlenmeyer flask for 56 d yielded 160 ppm pentachlorobiphenyl (Uyeta et al.,
1976). A photooxidation half-life of 6.17 months was reported for the vapor-phase reaction of
1,3,5-trichlorobenzene with OH radicals (Atkinson, 1985).
Purification Methods
Recrystallise it from dry *benzene or toluene. [Beilstein 5 IV 666.]
Toxicity evaluation
The liver is themain target of trichlorobenzenes irrespective of
the route of exposure. The mechanisms of liver toxicity
induced by these chemicals have not been illustrated. It might
involve intermediate arene oxides formed during initial
transformation to trichlorophenols. In addition, exposure
to 1,2,4-TCB induced porphyria in rats by inducing daminolevulinic
acid (ALA) synthetase, a rate-limiting enzyme
in the biosynthesis of heme, and also heme oxygenase, a ratelimiting
enzyme in the degradation of heme synthetase, and
therefore increasing heme production.
