General Description
A colorless liquid with a peculiar odor. Insoluble in water and less dense than water. Flash point near 123°F. May be toxic by ingestion and inhalation. Used to make plastics and dyes.
Reactivity Profile
TRIMETHYLBENZENE is incompatible with the following: Oxidizers, nitric acid .
Air & Water Reactions
Flammable. Insoluble in water.
Hazard
Moderate fire hazard. Toxic by inhalation.
Central nervous system impairment, asthma, and
hematologic effects.
Health Hazard
May cause toxic effects if inhaled or absorbed through skin. Inhalation or contact with material may irritate or burn skin and eyes. Fire will produce irritating, corrosive and/or toxic gases. Vapors may cause dizziness or suffocation. Runoff from fire control or dilution water may cause pollution.
Potential Exposure
Mesitylene is used as raw material in
chemical synthesis and as ultraviolet stabilizer; as a paint
thinner, solvent, and motor fuel component; as an intermediate in organic chemical manufacture.
Fire Hazard
HIGHLY FLAMMABLE: Will be easily ignited by heat, sparks or flames. Vapors may form explosive mixtures with air. Vapors may travel to source of ignition and flash back. Most vapors are heavier than air. They will spread along ground and collect in low or confined areas (sewers, basements, tanks). Vapor explosion hazard indoors, outdoors or in sewers. Runoff to sewer may create fire or explosion hazard. Containers may explode when heated. Many liquids are lighter than water.
First aid
If this chemical gets into the eyes, remove any
contact lenses at once and irrigate immediately for at least
15 minutes, occasionally lifting upper and lower lids. Seek
medical attention immediately. If this chemical contacts the
skin, remove contaminated clothing and wash immediately
with soap and water. Seek medical attention immediately.
If this chemical has been inhaled, remove from exposure,
begin rescue breathing (using universal precautions, including resuscitation mask) if breathing has stopped and CPR if
heart action has stopped. Transfer promptly to a medical
facility. When this chemical has been swallowed, get
medical attention. Give large quantities of water and induce
vomiting. Do not make an unconscious person vomit.
Shipping
UN1993 Flammable liquids, n.o.s., Hazard Class:
3; Labels: 3-Flammable liquid, Technical Name Required.
Incompatibilities
Vapors forms explosive mixture with air.
Violent reaction with nitric acid. 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
Description
Mesitylene is a clear, colorless liquid with a distinctive, aromatic odor. Molecular weight= 120.21; Specific gravity (H2O:1)= 0.86;Boiling point=165℃; Freezing/Melting point=45℃; Vapor pressure= 2 mmHg at 20℃; Flash point=50℃ (cc); Autoignition temperature=559℃. Hazard Identification (based on NFPA-704 M Rating System): Health 0, Flammability 2, Reactivity 0. Practically insoluble in water; solubility= 0.002%.
Waste Disposal
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.
Physical properties
Colorless liquid with a peculiar odor. An odor threshold concentration of 170 ppbv was reported
by Nagata and Takeuchi (1990).
Definition
ChEBI: A trimethylbenzene carrying methyl substituents at positions 1, 3 and 5.
Source
Detected in distilled water-soluble fractions of 87 octane gasoline (0.34 mg/L), 94 octane
gasoline (1.29 mg/L), Gasohol (0.48 mg/L), No. 2 fuel oil (0.08 mg/L), jet fuel A (0.09 mg/L),
diesel fuel (0.03 mg/L), and military jet fuel JP-4 (0.09 mg/L) (Potter, 1996). Schauer et al. (1999)
reported 1,3,5-trimethylbenzene in a diesel-powered medium-duty truck exhaust at an emission
rate of 260 μg/km.
California Phase II reformulated gasoline contained 1,3,5-trimethylbenzene at a concentration of
7.45 g/kg. Gas-phase tailpipe emission rates from gasoline-powered automobiles with and without
catalytic converters were 1.98 and 210 mg/km, respectively (Schauer et al., 2002).
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 1,3,5-trimethylbenzene concentrations reported in water-soluble fractions of
unleaded gasoline, kerosene, and diesel fuel were 333, 86, and 13 μg/L, respectively. When the
authors analyzed the aqueous-phase via U.S. EPA approved test method 610, average 1,3,5-
trimethylbenzene concentrations in water-soluble fractions of unleaded gasoline, kerosene, and
diesel fuel were greater, i.e., 441, 91, and 27 μg/L, respectively.
Drinking water standard: No MCLGs or MCLs have been proposed (U.S. EPA, 2000).
Environmental Fate
Biological. In anoxic groundwater near Bemidji, MI, 1,3,5-trimethylbenzene anaerobically
biodegraded to the intermediate tentatively identified as 3,5-dimethylbenzoic acid (Cozzarelli et
al., 1990).
Photolytic. Glyoxal, methylglyoxal, and biacetyl were produced from the photooxidation of
1,3,5-trimethylbenzene by OH radicals in air at 25 °C (Tuazon et al., 1986a). The rate constant for
the reaction of 1,3,5-trimethylbenzene and OH radicals at room temperature was 4.72 x 10-11
cm3/molecule?sec (Hansen et al., 1975). A rate constant of 2.97 x 10-8 L/molecule?sec was reported
for the reaction of 1,3,5-trimethylbenzene with OH radicals in the gas phase (Darnall et al., 1976).
Similarly, a room temperature rate constant of 6.05 x 10-11 cm3/molecule?sec was reported for the
vapor-phase reaction of 1,3,5-trimethylbenzene with OH radicals (Atkinson, 1985). At 25 °C, a
rate constant of 3.87 x 10-11 cm3/molecule?sec was reported for the same reaction (Ohta and
Ohyama, 1985).
Chemical/Physical. 1,3,5-Trimethylbenzene will not hydrolyze because it does not contain a
hydrolyzable functional group (Kollig, 1993).
storage
Color Code—Red: Flammability Hazard: Store in a flammable liquid storage area or approved cabinet away from ignition sources and corrosive and reactive materials. Prior to working with this chemical you should be trained on its proper handling and storage. This chemical must be stored to avoid contact with oxidizers (such as perchlorates, peroxides, permanganates, chlorates, and nitrates) and strong oxidizers (such as chlorine, bromine, and fluorine), since violent reactions occur. Store in tightly closed containers in a cool, well-ventilated area away from heat. Sources of ignition, such as smoking and open flames are prohibited where this chemical is used, handled, or stored in a manner that could create a potential fire or explosion hazard. Metal containers involving the transfer of 5 gallons or more of this chemical should be grounded and bonded. Drums must be equipped with self-closing valves, pressure vacuum bungs, and flame arresters. Use only nonsparking tools and equipment, especially when opening and closing containers of this chemical.
Purification Methods
Dry it with CaCl2 and distil it from Na in a glass helices-packed column. Treat it with silica gel and redistil it. Alternative purifications include vapour-phase chromatography, or fractional distillation followed by azeotropic distillation with 2-methoxyethanol (which is subsequently washed out with H2O), drying and fractional distilling. More exhaustive purification uses sulfonation by dissolving in two volumes of conc H2SO4, precipitating with four volumes of conc HCl at 0o, washing with conc HCl and recrystallising from CHCl3. The mesitylene sulfonic acid is hydrolysed with boiling 20% HCl and steam distilled. The separated mesitylene is dried (MgSO4 or CaSO4) and distilled. It can also be fractionally crystallised from the melt at low temperatures. [Beilstein 5 IV 1016.]
