MOLECULE

p-Xylene

p-Xylene, also known as para-xylene or p-methyltoluene, compounds known as benzene and substituted derivatives. These are aromatic compounds containing one monocyclic ring system consisting of benzene which is substituted by a variable number of methyl groups in different positions. As such, p-xylene is a monocyclic benzene carrying two methyl groups at positions 1 and 4. p-Xylene occurs naturally in petroleum and coal tar. It is a constitutional isomer of m-xylene and o-xylene, the mixture being called xylene or xylenes. It is emitted by most combustion sources, including automobile exhaust and tobacco smoke. It has also been reported to a volatile component of cannabis plants (PMID: 26657499). p-Xylene is a colorless, slightly oily flammable liquid. p-Xylene has been detected, but not quantified in, several different foods, such as pepper (C. annuum), green bell peppers, parsley, yellow bell peppers, and red bell peppers. This could make p-xylene a potential biomarker for the consumption of these foods. p-Xylene is a potentially toxic compound. Inhaling p-xylene can cause dizziness, headache, drowsiness, and nausea. If p-xylene is ingested one's mouth should be rinsed, and vomiting should not be induced. p-Xylene can cause issues with the central nervous system and if swallowed could cause chemical pneumonitis when breathed into the lungs. It is a component in the production of terephthalic acid for polyesters such as polyethylene terephthalate (generally known as PET).