The key difference between toluene and xylene is that toluene contains one methyl group attached to a benzene ring whereas xylene contains two methyl groups attached to a benzene ring.
Both toluene and xylene are important organic compounds having closely similar chemical structures. Both these are aromatic compounds containing benzene rings and attached methyl group(s).
CONTENTS
1. Overview and Key Difference
2. What is Toluene
3. What is Xylene
4. Side by Side Comparison – Toluene vs Xylene in Tabular Form
5. Summary
What is Toluene?
Toluene is an organic compound having the chemical formula C7H8. The IUPAC name for toluene is methylbenzene. It contains a benzene ring attached to a methyl group. The molar mass of this compound is about 92.14 g/mol. At room temperature and pressure, it appears as a colourless liquid having a pungent benzene-like odour.
Figure 01: The Chemical Structure of Toluene
The boiling point of toluene is about 111°C. It is a highly flammable liquid compound. It is considered as a benzene derivative. It can undergo electrophilic aromatic substitution reactions. Toluene is highly reactive due to the presence of a methyl group. Methyl groups are good electron releasing groups. Therefore, the methyl group present in the toluene molecule helps to make the benzene ring more electron-rich. Hence, it can easily share electrons with electrophiles.
Toluene is very useful in organic reactions. It can be used as a starting material to produce benzene. It gives a benzene molecule along with a methane (CH4) molecule as the end products. Toluene is a good solvent that is commonly used in the production of paints. It is sometimes used as a fuel due to its high flammability. However, toluene is considered as a toxic compound.
What is Xylene?
Xylene is an organic compound having the chemical formula (CH3)2C6H4. It falls under the category of dimethylbenzene because it has a benzene with two attached methyl groups. Furthermore, this compound has three isomers whose positions of methyl groups on the benzene ring are different from each other. All these three isomers occur as colourless, flammable liquids; more precisely, a mixture of these isomers is called “xylenes”.
Figure 02: Xylene Structure
The production of xylene can be done by catalytic reforming during petroleum refining or by coal carbonization during the manufacture of coke fuel. However, industrially, xylene production method we use is the methylation of toluene and benzene.
Xylene is important as a nonpolar solvent. It is, however, expensive and comparatively toxic. The nonpolar nature is due to the low difference of electronegativity between C and H. Therefore, xylene tends to dissolve lipophilic substances well.
According to the place where two methyl groups are attached to the benzene ring, there are three types of xylene as o-xylene, p-xylene and m-xylene. These three terms stand for ortho, para and meta positions of the two methyl groups.
What is the Difference Between Toluene and Xylene?
Toluene and xylene are aromatic organic compounds. The key difference between toluene and xylene is that toluene contains one methyl group attached to a benzene ring whereas xylene contains two methyl groups attached to a benzene ring.
The following table shows more comprisons related to the difference between toluene and xylene.
Summary – Toluene vs Xylene
Toluene and xylene are aromatic organic compounds. The key difference between toluene and xylene is that toluene contains one methyl group attached to a benzene ring whereas xylene contains two methyl groups attached to a benzene ring.
Reference:
1. “Toluene.” Wikipedia, Wikimedia Foundation, 4 May 2020, Available here.
Image Courtesy:
1. “Toluol” By NEUROtiker – Own work (Public Domain) via Commons Wikimedia
2. “IUPAC-cyclic” By Fvasconcellos 20:19, 8 January 2008 (UTC). Original image by DrBob (talk · contribs). – Vector version of Image:Iupac-cyclic.png by DrBob (talk · contribs) (CC BY-SA 3.0) via Commons Wikimedia