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.)

Flash point:

119 °F

solubility 

Soluble in acetone, alcohol, benzene, and ether (Weast, 1986)

pka

>14 (Schwarzenbach et al., 1993)

color 

Colorless to Light yellow

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).

Dielectric constant

2.6600000000000001

Stability:

Stable. Flammable. Incompatible with strong oxidizing agents.

LogP

3.660

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

OEB

A

OEL

TWA: 25 ppm (125 mg/m3)

WGK Germany 

3

RTECS 

DC3300000

Autoignition Temperature

878 °F

HazardClass 

3.2

PackingGroup 

III

HS Code 

2902900000

Hazardous Substances Data

526-73-8(Hazardous Substances Data)

MSDS

• Language:English Provider:SigmaAldrich

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.

Synthesis Reference(s)

Journal of the American Chemical Society, 62, p. 2639, 1940 DOI: 10.1021/ja01867a017
Organic Syntheses, Coll. Vol. 4, p. 508, 1963

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.

Environmental Fate

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).

Shipping

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:

Incompatibilities

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.

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.

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