What Is Trimethylbenzene?
Trimethylbenzene is an aromatic hydrocarbon with the chemical formula C9H12 and a molecular weight of 120.19. It is a colorless liquid with a characteristic odor, consisting of three isomers where three hydrogen atoms on the benzene ring are replaced with methyl groups.
The isomers include:
- 1,2,3-Trimethylbenzene (Hemimellitene), with methyl groups at the first, second, and third positions.
- 1,2,4-Trimethylbenzene (Pseudocumene), with methyl groups at the first, second, and fourth positions.
- 1,3,5-Trimethylbenzene (Mesitylene), with methyl groups at the first, third, and fifth positions.
All are obtained from high-boiling fractions of tar gas oil.
Uses of Trimethylbenzene
Trimethylbenzene is primarily used as a raw material for the synthesis of pigments, dyes, pharmaceuticals, and industrial chemicals. 1,2,4-trimethylbenzene serves as a gasoline additive and an SD solvent. 1,3,5-trimethylbenzene is used as a high-boiling solvent and an etchant in semiconductor wafer mapping.
Other Information on Trimethylbenzene
1. Properties of Trimethylbenzene
Trimethylbenzene has a melting point ranging from -2 to -45 °C, a boiling point of 165 to 176 °C, a flash point of 44 to 53 °C, and a specific gravity of 0.86 to 0.89 g/mL. It is insoluble in water but soluble in organic solvents. Each isomer has specific properties such as melting points, boiling points, specific gravities, and odors.
2. Production Process of Trimethylbenzene
Trimethylbenzene is found in kerosene, diesel oil, and gasoline, and can be obtained by distilling and refining crude oil. It is also synthesized through methods such as dehydration and condensation of acetone using tantalum- or niobium-based catalysts, or by trimerization of propine in sulfuric acid.
3. Handling of Trimethylbenzene
Trimethylbenzene should be handled in a closed container and stored in a cool, well-ventilated place, away from ignition sources. It is extremely flammable and can form explosive mixtures with air. Oxidizing materials should be avoided, and protective measures such as gloves, eye protection, and masks are recommended. Only use it outdoors or in well-ventilated areas and avoid inhalation of mists, vapors, and sprays.