Trimethylbenzenes exists in three isomeric
forms. All isomers are clear, colorless liquids with a distinctive,
aromatic odor.
Clear, colorless, flammable liquid with an aromatic odor similar to propylbenzene, ethylbenzenes,
or xylenes.
Raw material for chemical synthesis.
ChEBI: A trimethylbenzene carrying methyl groups at positions 1, 2 and 3. It has been found in Centaurium erythraea.
Journal of the American Chemical Society, 62, p. 2639, 1940
DOI: 10.1021/ja01867a017Organic Syntheses, Coll. Vol. 4, p. 508, 1963
Combustible. Central nervous system
impairment, asthma, and hematologic effects.
Mildly toxic by
ingestion, Flammable liquid when exposed
to heat, sparks, or flame. To fight fire, use
water spray, mist, dry chemical, CO2, foam.
When heated to decomposition it emits
acrid smoke and irritating fumes.
(1,2,3-and 1,2,4-isomers): These materials
are used as solvents and in dye and perfume manufacture.
The 1,2,3-isomer is used as raw material in chemical
synthesis and as an UV stabilizer. The 1,2,4-isomer is used
as the raw material for trimellitic anhydride manufacture.
These compounds are found in diesel engine exhaust
fumes.
Detected in distilled water-soluble fractions of 87 octane gasoline (0.30 mg/L), 94 octane
gasoline (0.81 mg/L), Gasohol (0.80 mg/L), No. 2 fuel oil (0.22 mg/L), diesel fuel (0.09 mg/L),
and military jet fuel JP-4 (0.19 mg/L) (Potter, 1996).
Thomas and Delfino (1991) equilibrated contaminant-free groundwater collected from
Gainesville, FL with individual fractions of three individual petroleum products at 24–25 °C for
24 h. The aqueous phase was analyzed for organic compounds via U.S. EPA approved test method
602. Average 1,2,3-trimethylbenzene concentrations detected in water-soluble fractions of
unleaded gasoline, kerosene, and diesel fuel were 1.219, 0.405, and 0.118 mg/L, respectively.
When the authors analyzed the aqueous-phase via U.S. EPA approved test method 610, average
1,2,3-trimethylbenzene concentrations in water-soluble fractions of unleaded gasoline, kerosene,
and diesel fuel were smaller, i.e., 742, 291, and 105 μg/L, respectively.
Photolytic. Glyoxal, methylglyoxal, and biacetyl were produced from the photooxidation of
1,2,3-trimethylbenzene by OH radicals in air at 25 °C (Tuazon et al., 1986a). The rate constant for
the reaction of 1,2,3-trimethylbenzene and OH radicals at room temperature was 1.53 x 10-11
cm3/molecule?sec (Hansen et al., 1975). A rate constant of 1.49 x 10-8 L/molecule?sec was reported
for the reaction of 1,2,3-trimethylbenzene with OH radicals in the gas phase (Darnall et al., 1976).
Similarly, a room temperature rate constant of 3.16 x 10-11 cm3/molecule?sec was reported for the
vapor-phase reaction of 1,2,3-trimethylbenzene with OH radicals (Atkinson, 1985). At 25 °C, a
rate constant of 2.69 x 10-11 cm3/molecule?sec was reported for the same reaction (Ohta and
Ohyama, 1985). 2,3-Butanedione was the only products identified from the OH radical-initiated
reaction of 1,2,4-trimethylbenzene in the presence of nitrogen dioxide. The amount of 2,3-
butanedione formed decreased with increased concentration of nitrogen dioxide (Bethel et al.,
2000).
Chemical/Physical. 1,2,3-Trimethylbenzene will not hydrolyze because it does not contain a
hydrolyzable group (Kollig, 1993).
UN3295 Hydrocarbons, liquid, n.o.s., Hazard
Class: 3; Labels: 3-Flammable liquid. UN1993 Flammable
liquids, n.o.s., Hazard Class: 3; Labels: 3-Flammable liquid,
Technical Name Required. 1,3,5-Trimethylbenzene;
UN2325, Hazard Class: 3; Labels: 3-Flammable liquid.
1,2,4-Trimethylbenzene:
Vapors may form explosive mixture with
air. Incompatible with oxidizers (chlorates, nitrates, peroxides,
permanganates, perchlorates, chlorine, bromine, fluorine,
etc.); contact may cause fires or explosions. Keep
away from alkaline materials, strong bases, strong acids,
oxoacids, epoxides.
Dissolve or mix the material
with a combustible solvent and burn in a chemical incinerator
equipped with an afterburner and scrubber. All federal,
state, and local environmental regulations must be
observed.
