Durene, or 1,2,4,5-tetramethylbenzene, is an

organic compound Some chemical authorities define an organic compound as a chemical compound that contains a carbon–hydrogen or carbon–carbon bond; others consider an organic compound to be any chemical compound that contains carbon. For example, carbon-co ...

with the formula C₆H₂(CH₃)₄. It is a colourless solid with a sweet odor. The compound is classified as an

alkylbenzene An alkylbenzene is a chemical compound that contains a monocyclic aromatic ring attaching to one or more saturated hydrocarbon chains. Alkylbenzenes are derivatives of benzene, in which one or more hydrogen atoms are replaced by alkyl groups. The ...

. It is one of three isomers of tetramethylbenzene, the other two being prehnitene (1,2,3,4-tetramethylbenzene) and isodurene (1,2,3,5-tetramethylbenzene). Durene has an unusually high melting point (79.2 °C), reflecting its high molecular symmetry.

Production

It is a component of coal tar and was first prepared from pseudocumene in 1870. It is produced by

methylation Methylation, in the chemistry, chemical sciences, is the addition of a methyl group on a substrate (chemistry), substrate, or the substitution of an atom (or group) by a methyl group. Methylation is a form of alkylation, with a methyl group replac ...

of other methylated benzene compounds such as ''p''-xylene and pseudocumene. :C₆H₄(CH₃)₂ + 2 CH₃Cl → C₆H₂(CH₃)₄ + 2 HCl In industry, a mixture of

xylene In organic chemistry, xylene or xylol (; IUPAC name: dimethylbenzene) are any of three organic compounds with the formula . They are derived from the substitution of two hydrogen atoms with methyl groups in a benzene ring; which hydrogens are su ...

s and trimethylbenzenes is alkylated with

methanol Methanol (also called methyl alcohol and wood spirit, amongst other names) is an organic chemical compound and the simplest aliphatic Alcohol (chemistry), alcohol, with the chemical formula (a methyl group linked to a hydroxyl group, often ab ...

. Durene can be separated from its isomers by selective crystallization, exploiting its high melting point. The original synthesis of durene involved a similar reaction starting from

toluene Toluene (), also known as toluol (), is a substituted aromatic hydrocarbon with the chemical formula , often abbreviated as , where Ph stands for the phenyl group. It is a colorless, water Water is an inorganic compound with the c ...

. Durene is a significant byproduct of the production of gasoline from

via the "MTG (Methanol to Gasoline) process".

Reactions and uses

It is a relatively easily oxidized benzene derivative, with E_1/2 of 2.03 V vs NHE. Its nucleophilicity is comparable to that of

phenol Phenol (also known as carbolic acid, phenolic acid, or benzenol) is an aromatic organic compound with the molecular formula . It is a white crystalline solid that is volatile and can catch fire. The molecule consists of a phenyl group () ...

. It is readily halogenated on the ring for example. Nitration gives the dinitro derivative, a precursor to duroquinone. In industry, it is the precursor to

pyromellitic dianhydride Pyromellitic dianhydride (PMDA) is an organic compound with the formula C6H2(C2O3)2. It is the double carboxylic acid anhydride that is used in the preparation of polyimide polymers such as Kapton. It is a white, hygroscopic solid. It forms a hyd ...

, which is used for manufacturing curing agents,

adhesives Adhesive, also known as glue, cement, mucilage, or paste, is any non-metallic substance applied to one or both surfaces of two separate items that binds them together and resists their separation. The use of adhesives offers certain advantage ...

, coating materials. It is used in the manufacture of some raw materials for engineering plastics ( polyimides) and cross-linking agent for

alkyd An alkyd is a polyester resin modified by the addition of fatty acids and other components. Alkyds are derived from polyols and organic acids including dicarboxylic acids or carboxylic acid anhydride and triglyceride oils. The term ''alkyd'' is ...

resin A resin is a solid or highly viscous liquid that can be converted into a polymer. Resins may be biological or synthetic in origin, but are typically harvested from plants. Resins are mixtures of organic compounds, predominantly terpenes. Commo ...

s. It is also a suitable starting material for the synthesis of hexamethylbenzene. With a simple

proton NMR Proton nuclear magnetic resonance (proton NMR, hydrogen-1 NMR, or 1H NMR) is the application of nuclear magnetic resonance in NMR spectroscopy with respect to hydrogen-1 nuclei within the molecules of a substance, in order to determine the stru ...

spectrum comprising two signals due to the 2 aromatic hydrogens (2H) and four methyl groups (12H), durene is used as an internal standard.

Safety

Durene is not a skin irritant nor a skin sensitizer or eye irritant. Durene is only slightly toxic on an acute toxicologic basis and only poses an acute health hazard when ingested in excessive quantities. Dennis W. Lynch, Vernon B. Perone, Ronald L. Schuler, William B. Ushry & Trent R. Lewis, Journal Drug and Chemical Toxicology Volume 1, 1978 - Issue 3, Pages 219-230 (2008)

References

{{Hydrocarbons Hydrocarbon solvents Alkylbenzenes C4-Benzenes