The common name for 1,3-dimethylbenzene is m-Xylene, also known as m-dimethylbenzene.
Understanding 1,3-Dimethylbenzene
1,3-Dimethylbenzene is an aromatic hydrocarbon, meaning it is a compound containing a benzene ring with additional substituents. In this case, it has two methyl (-CH₃) groups attached to the benzene ring. The "1,3" in its systematic name indicates that these two methyl groups are located at the first and third positions on the benzene ring, relative to each other.
This compound belongs to a class of organic compounds broadly known as xylenes. The term "xylene" (from Greek xylon meaning wood, as it was first isolated from crude wood spirit) refers specifically to any of the three isomers of dimethylbenzene.
Xylene Isomers
The position of the two methyl groups on the benzene ring gives rise to three distinct isomers, each with its own common name:
- o-Xylene (ortho-xylene) or 1,2-Dimethylbenzene: Here, the two methyl groups are adjacent to each other on the benzene ring (positions 1 and 2).
- m-Xylene (meta-xylene) or 1,3-Dimethylbenzene: In this isomer, the two methyl groups are separated by one carbon atom on the ring (positions 1 and 3). This is the compound in question.
- p-Xylene (para-xylene) or 1,4-Dimethylbenzene: The methyl groups are directly opposite each other on the benzene ring (positions 1 and 4).
These isomers share the same chemical formula (C₈H₁₀) but differ in their structural arrangement, leading to variations in their physical and chemical properties.
Comparison of Xylene Isomers
To better illustrate the differences, here's a brief comparison of the xylene isomers:
| Isomer | IUPAC Name | Structure Representation (Methyl Group Positions) | Common Name(s) |
|---|---|---|---|
| 1,2-Dimethylbenzene | 1,2-Dimethylbenzene | Adjacent (ortho) | o-Xylene, ortho-xylene |
| 1,3-Dimethylbenzene | 1,3-Dimethylbenzene | Separated by one carbon (meta) | m-Xylene, m-dimethylbenzene |
| 1,4-Dimethylbenzene | 1,4-Dimethylbenzene | Opposite (para) | p-Xylene, para-xylene |
All three xylene isomers are important industrial chemicals, often used as solvents or as feedstocks in the production of various plastics, fibers, and other organic compounds. For example, p-xylene is a key precursor to terephthalic acid, which is used in the manufacture of PET plastic.
The common naming convention (ortho-, meta-, para-) provides a quick and easy way to distinguish between these closely related aromatic compounds, especially in industrial and commercial contexts.
