Mesitylene

In organic chemistry, mesitylene or 1,3,5-trimethylbenzene (C9H12) is an aromatic hydrocarbon with three methyl substituents attached to the benzene ring. It is prepared from distillation of acetone with sulfuric acid or by the trimerization of propyne in sulfuric acid, which in both cases acts as a homogeneous catalyst and dehydrating agent. It is commonly used as a solvent in research and industry. Mesitylene is flammable and an irritant. Mesitylene has a very low freezing point.

In the electronics industry, mesitylene has also been used as a developer for photopatternable silicones due to its solvent properties.

1,3,5-Trimethylbenzene is also a major urban volatile organic compound (VOC) which results from combustion. It plays a significant role in aerosol and tropospheric ozone formation as well as other reactions in atmospheric chemistry.