NIOSH Pocket Guide to Chemical Hazards

1,2,4-Trimethylbenzene CAS 95-63-6
C6H3(CH3)3 RTECS DC3325000
Synonyms & Trade Names
Assymetrical trimethylbenzene, psi-Cumene, Pseudocumene [Note: Hemimellite is a mixture of the 1,2,3-isomer with up to 10% of related aromatics such as the 1,2,4-isomer.]
DOT ID & Guide
NIOSH REL: TWA 25 ppm (125 mg/m3)
OSHA PEL†: none
IDLH N.D. Conversion 1 ppm = 4.92 mg/m3
Physical Description
Clear, colorless liquid with a distinctive, aromatic odor.
MW: 120.2
BP: 337°F
FRZ: -77°F
Sol: 0.006%
VP(56°F): 1 mmHg
IP: 8.27 eV

Sp.Gr: 0.88
Fl.P: 112°F
UEL: 6.4%
LEL: 0.9%

Class II Flammable Liquid
Incompatibilities & Reactivities
Oxidizers, nitric acid
Measurement Methods
None available
Personal Protection & Sanitation
Skin: Prevent skin contact
Eyes: Prevent eye contact
Wash skin: When contaminated
Remove: When wet or contaminated
Change: No recommendation

First Aid (See procedures)
Eye: Irrigate immediately
Skin: Soap wash
Breathing: Respiratory support
Swallow: Medical attention immediately
Respirator Recommendations To be added later
Exposure Routes inhalation, ingestion, skin and/or eye contact
Symptoms Irritation eyes, skin, nose, throat, respiratory system; bronchitis; hypochromic anemia; headache, drowsiness, fatigue, dizziness, nausea, incoordination; vomiting, confusion; chemical pneumonitis (aspiration liquid)
Target Organs Eyes, skin, respiratory system, central nervous system, blood