1,2,4-Trimethylbenzene

1,2,4-Trimethylbenzene, also known as pseudocumene, is an organic compound with the chemical formula C₆H₃(CH₃)₃. Classified as an aromatic hydrocarbon, it is a flammable colorless liquid with a strong odor. It is nearly insoluble in water but soluble in organic solvents. It occurs naturally in coal tar and petroleum (about 3%). It is one of the three isomers of trimethylbenzene.

1,2,4-Trimethylbenzene^[1]

Skeletal formula Ball-and-stick model
Names
Preferred IUPAC name 1,2,4-Trimethylbenzene
Other names Pseudocumene, Asymmetrical trimethylbenzene, ψ-Cumene
Identifiers
CAS Number	95-63-6 Y
3D model (JSmol)	Interactive image
Beilstein Reference	1903005
ChEBI	CHEBI:34039 Y
ChEMBL	ChEMBL1797280
ChemSpider	6977 Y
ECHA InfoCard	100.002.216
EC Number	202-436-9
KEGG	C14533 Y
PubChem CID	7247
RTECS number	DC3325000
UNII	34X0W8052F Y
UN number	1993 2325
CompTox Dashboard (EPA)	DTXSID6021402
InChI InChI=1S/C9H12/c1-7-4-5-8(2)9(3)6-7/h4-6H,1-3H3 Y Key: GWHJZXXIDMPWGX-UHFFFAOYSA-N Y InChI=1/C9H12/c1-7-4-5-8(2)9(3)6-7/h4-6H,1-3H3 Key: GWHJZXXIDMPWGX-UHFFFAOYAF
SMILES c1c(ccc(c1C)C)C
Properties
Chemical formula	C9H12
Molar mass	120.19 g/mol
Appearance	Colorless liquid
Density	0.8761 g/cm3
Melting point	−43.78 °C (−46.80 °F; 229.37 K)
Boiling point	169 to 171 °C (336 to 340 °F; 442 to 444 K)
Magnetic susceptibility (χ)	-101.6·10−6 cm3/mol
Hazards
GHS labelling:
Pictograms
Signal word	Warning
Hazard statements	H226, H315, H319, H332, H335, H411
Precautionary statements	P210, P233, P240, P241, P242, P243, P261, P264, P271, P273, P280, P302+P352, P303+P361+P353, P304+P312, P304+P340, P305+P351+P338, P312, P321, P332+P313, P337+P313, P362, P370+P378, P391, P403+P233, P403+P235, P405, P501
Flash point	44.4 °C (111.9 °F; 317.5 K)
Explosive limits	0.9%–6.4%[2]
NIOSH (US health exposure limits):
PEL (Permissible)	none[2]
Safety data sheet (SDS)	Sigma-Aldrich MSDS
Related compounds
Related compounds	1,2,3-Trimethylbenzene; 1,3,5-Trimethylbenzene
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). Y verify (what is YN ?) Infobox references

Production

Industrially, it is isolated from the C₉ aromatic hydrocarbon fraction during petroleum distillation. Approximately 40% of this fraction is 1,2,4-trimethylbenzene. It is also generated by methylation of toluene and xylenes and the disproportionation of xylene over aluminosilicate catalysts.^[3]

Uses

Pseudocumene is a precursor to mellitic anhydride, from which high performance polymers are made. It is also used as a sterilizing agent and in the making of dyes, perfumes and resins. Another use is as a gasoline additive.^[4]

Scintillator

1,2,4-Trimethylbenzene dissolved in mineral oil is used as a liquid scintillator^[5] in particle physics experiments such as NOνA and Borexino.

See also

• Cumene

References

1. Merck Index, 11th Edition, 7929
2. NIOSH Pocket Guide to Chemical Hazards. "#0638". National Institute for Occupational Safety and Health (NIOSH).
3. Karl Griesbaum, Arno Behr, Dieter Biedenkapp, Heinz-Werner Voges, Dorothea Garbe, Christian Paetz, Gerd Collin, Dieter Mayer, Hartmut Höke "Hydrocarbons" in Ullmann's Encyclopedia of Industrial Chemistry 2002 Wiley-VCH, Weinheim. doi:10.1002/14356007.a13_227
4. "Chemical Summary for 1,2,4-Trimethylbenzene" (text). United States Environmental Protection Agency. 1994-08-01. Retrieved 2008-01-28.
5. Mufson, S.; et al. (November 1, 2015). "Liquid scintillator production for the NOvA experiment". Nuclear Instruments and Methods A. 799: 1–9. arXiv:1504.04035. Bibcode:2015NIMPA.799....1M. doi:10.1016/j.nima.2015.07.026. S2CID 118578183.

External links

• EPA Chemical Fact Sheet
• CDC – NIOSH Pocket Guide to Chemical Hazards