Mesityl

Mesitylene

Names
Preferred IUPAC name 1,3,5-Trimethylbenzene
Other names Mesitylene sym-Trimethylbenzene
Identifiers
CAS Number	108-67-8 Y
3D model (Jmol)	Interactive image
ChEBI	CHEBI:34833 Y
ChemSpider	7659 Y
ECHA InfoCard	100.003.278
EC Number	203-604-4
KEGG	C14508 Y
PubChem CID	7947
UN number	2325
InChI InChI=1S/C9H12/c1-7-4-8(2)6-9(3)5-7/h4-6H,1-3H3 Y Key: AUHZEENZYGFFBQ-UHFFFAOYSA-N Y InChI=1/C9H12/c1-7-4-8(2)6-9(3)5-7/h4-6H,1-3H3 Key: AUHZEENZYGFFBQ-UHFFFAOYAK
SMILES Cc1cc(cc(c1)C)C
Properties
Chemical formula	C9H12
Molar mass	120.19 g/mol
Appearance	Clear, colorless liquid
Odor	Distinctive, aromatic
Density	0.8637 g/cm3 at 20 °C
Melting point	−44.8 °C (−48.6 °F; 228.3 K)
Boiling point	164.7 °C (328.5 °F; 437.8 K)
Solubility in water	0.002% (20°C)
Vapor pressure	2 mmHg (20°C)
Magnetic susceptibility (χ)	-92.32·10−6 cm3/mol
Structure
Dipole moment	0.047 D
Hazards
Safety data sheet	Safety data from Sigma Aldrich
Flash point	50 °C; 122 °F; 323 K
US health exposure limits (NIOSH):
PEL (Permissible)	none
REL (Recommended)	TWA 25 ppm (125 mg/m3)
IDLH (Immediate danger)	N.D.
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
Y  (what is YN ?)
Infobox references

Mesitylene or 1,3,5-trimethylbenzene is a derivative of benzene with three methyl substituents positioned symmetrically around the ring. The other two isomeric trimethylbenzenes are 1,2,4-trimethylbenzene (pseudocumene) and 1,2,3-trimethylbenzene (hemimellitene). All three compounds have the formula C₆H₃(CH₃)₃, which is commonly abbreviated C₆H₃Me₃. Mesitylene is a colourless liquid with sweet aromatic odor. It is a component of coal tar, which is its traditional source. It is a precursor to diverse fine chemicals. The mesityl group (Mes) is a substituent with the formula C₆H₂Me₃ and is found in various other compounds.

Mesitylene is prepared by equilibration of xylene (or simple methyl alkylation of it) over solid acid catalyst:

Although impractical, it could be prepared by trimerization of propyne, also requiring an acid catalyst, affords a mixture of 1,3,5- and 1,2,4-trimethylbenzenes.

Catalyzing and dehydrating by sulfuric acid, trimerization of acetone via aldol condensation also affords mesitylene.

Oxidation of mesitylene with nitric acid affords trimesic acid, C₆H₃(COOH)₃. Using manganese dioxide, a milder oxidising agent, 3,5-dimethylbenzaldehyde is formed. Mesitylene is oxidised by trifluoroperacetic acid to produce mesitol (2,4,6-trimethylphenol).