Toluene is known as methylbenzene or phenylmethane. It is a clear, water-insoluble liquid with the typical smell of paint thinners, redolent of the sweet smell of the related compound benzene. It is an aromatic hydrocarbon, which is used as an industrial feedstock and as a solvent. Toluene reacts as a normal aromatic hydrocarbon towards electrophilic aromatic substitution. Toluene is used as an octane booster in gasoline fuels used in internal combustion engines. Toluene is used to break open red blood cells in order to extract hemoglobin in biochemistry experiments.