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Hexamethylbenzene, also known as mellitene, is a hydrocarbon with the molecular formula C 12 H 18 and the condensed structural formula C 6 (CH 3) 6. It is an aromatic compound and a derivative of benzene , where benzene's six hydrogen atoms have each been replaced by a methyl group .
It is one of the three isomers of dimethylbenzene known collectively as xylenes. The m-stands for meta-, indicating that the two methyl groups in m-xylene occupy positions 1 and 3 on a benzene ring. It is in the positions of the two methyl groups, their arene substitution pattern, that it differs from the other isomers, o-xylene and p-xylene.
The boiling point for each isomer is around 140 °C (284 °F). The density of each isomer is around 0.87 g/mL (7.3 lb/US gal; 8.7 lb/imp gal) and thus is less dense than water. The odor of xylene is detectable at concentrations as low as 0.08 to 3.7 ppm (parts of xylene per million parts of air) and can be tasted in water at 0.53 to 1.8 ppm.
In organic chemistry, two molecules are valence isomers when they are constitutional isomers that can interconvert through pericyclic reactions. [1] [2] Benzene
It is one of the three isomers of trimethylbenzene. It is used in jet fuel, mixed with other hydrocarbons, to prevent the formation of solid particles which might damage the engine. German chemist Oscar Jacobsen first prepared the hydrocarbon in 1882 and designated it hemellitol as a reference to the trivial name of hexamethylbenzene. [4]
For the hydrocarbons with no further unsaturation, there are four isomers. The chemical formula for all the saturated isomers is C 9 H 12 . There are three trimethylbenzenes , three ethylmetylbenzenes, and two propylbenzene isomers. 1980s American gasoline contained about 3-4% C 3 -benzenes.
Alkylbenzene isomers can be differentiated by observing the position of alkyl substituents on the benzene ring using chemical ionization-proton exchange mass spectrometry. Conventional GC-MS yields limited results because the isomers have identical molecular weight and substituents.
The compound with the formula (C 5 H 5) 2 Fe 2 (CO) 4 exists as three isomers in solution. In one isomer the CO ligands are terminal. When a pair of CO are bridging, cis and trans isomers are possible depending on the location of the C 5 H 5 groups. [7] Another example in organometallic chemistry is the linkage isomerization of ...