Trimethyl benzene isomers

Synonyms

Mesitylene; Symmetrical trimethylbenzene; sym-Trimethylbenzene; Assymetrical trimethylbenzene; psi-Cumene; Pseudocumene; Hemimellitene; Hemelitol; [NIOSH] Methylxylene; Trimethyl benzene; Benzene, trimethyl-; Benzene, trimethyl- (mixed isomers); Trimethylbenzenes; [ChemIDplus] 1,2,3-Trimethylbenzene; 1,2,4-Trimethylbenzene; 1,3,5-Trimethylbenzene; [Hawley] UN1993; UN2325 (1,3,5-Trimethylbenzene)

Category

Aromatic Solvents

Description

Clear, colorless liquid with a distinctive, aromatic odor; [NIOSH]

Sources/Uses

Used in the synthesis of organic chemicals; also used in plastics as an ultraviolet stabilizer and in solvents; [ACGIH]

Comments

Hemimellitene is a mixture of the 1,2,3-isomer with up to 10% of related aromatics such as the 1,2,4-isomer. Hemelitol is the 1,2,3-isomer. [NIOSH] A skin, eye, and respiratory tract irritant; Inhalation of high concentrations may cause CNS effects; [ICSC] TLV Basis: CNS impairment and hematologic effects; "This value [TLV] should protect against hematologic effects, such as reversible increased reticulocyte counts observed in female Wistar rats exposed to 1,2,3-TMB, for which the LOAEL was 25 ppm. In addition, it would protect against a significant dose-dependent decrease erythrocytes among male Wistar rats exposed to 1,2,4-TMB for which the NOAEL was 100 ppm." [ACGIH]

Biomedical References

Insufficient data

10 ppm, mixed isomers

20 ppm

2.1 mm Hg

0.006 ppm

Odor Threshold High

2.4 ppm

Explanatory Notes

Detection odor threshold from AIHA (mean = 2.4 ppm and 2.2 ppm respectively for 1,2,4-trimethyl benzene and 1,3,5-trimethyl benzene); The Guide from the Emergency Response Guidebook is for "1,3,5-Trimethylbenzene."

high ambient temp required

Acute solvent syndrome

Not Classifiable

Diseases

Occupational diseases associated with exposure to this agent:

• Solvents, acute toxic effect