1,2,3-Trimethylbenzene Basic information
Product Name: 1,2,3-Trimethylbenzene
Synonyms: 1,2,3-trimethyl-benzen;1,2,3-trimethylbenzene (hemimellitene);benzene,1,2,3-trimethyl-;hemimellitol;1,2,3-TRIMETHYLBENZENE;1,2,3-trimethylbenzene(1,2,3-tmb);HEMELLITOL;HEMIMELLITENE
CAS: 526-73-8
MF: C9H12
MW: 120.19
EINECS: 208-394-8

1,2,3-Trimethylbenzene Chemical Properties
Melting point  −25 °C(lit.)
Boiling point  175-176 °C(lit.)
density  0.894 g/mL at 25 °C(lit.)
vapor density  4.15 (vs air)
vapor pressure  3.4 mm Hg ( 37.7 °C)
refractive index  n20/D 1.513(lit.)
Fp  119 °F
solubility  Soluble in acetone, alcohol, benzene, and ether (Weast, 1986)
pka >14 (Schwarzenbach et al., 1993)
form  neat
Odor Threshold 0.032ppm
Water Solubility  65.51mg/L(25 ºC)
BRN  1903410
Henry's Law Constant 3.18 at 25 °C (approximate - calculated from water solubility and vapor pressure)
Exposure limits NIOSH REL: TWA 25 ppm (125 mg/m3); ACGIH TLV: TWA for mixed isomers 25 ppm (adopted).
Stability: Stable. Flammable. Incompatible with strong oxidizing agents.
CAS DataBase Reference 526-73-8(CAS DataBase Reference)
NIST Chemistry Reference Benzene, 1,2,3-trimethyl-(526-73-8)
EPA Substance Registry System 1,2,3-Trimethylbenzene (526-73-8)
Safety Information
Hazard Codes  Xi
Risk Statements  10-37-36/37/38
Safety Statements  16-26
RIDADR  UN 3295 3/PG 3
WGK Germany  3
RTECS  DC3300000
Autoignition Temperature 878 °F
HazardClass  3.2
PackingGroup  III
Hazardous Substances Data 526-73-8(Hazardous Substances Data)

1,2,3-Trimethylbenzene Usage And Synthesis
Chemical Properties colourless liquid
Chemical Properties Trimethylbenzenes exists in three isomeric forms. All isomers are clear, colorless liquids with a distinctive, aromatic odor.
Physical properties Clear, colorless, flammable liquid with an aromatic odor similar to propylbenzene, ethylbenzenes, or xylenes.
Uses Raw material for chemical synthesis.
Definition ChEBI: A trimethylbenzene carrying methyl groups at positions 1, 2 and 3. It has been found in Centaurium erythraea.
Hazard Combustible. Central nervous system impairment, asthma, and hematologic effects.
Safety Profile 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.
Potential Exposure (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.
Source 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.