The C4-benzenes are a class of organic aromatic compounds which contain a benzene ring and four other carbon atoms. There are three tetramethylbenzenes, six dimethylethylbenzenes, three diethylbenzenes, three isopropylmethylbenzenes, three n-propylmethylbenzenes and four butylbenzenes. The saturated compounds have formula C10H14 and molecular weight 134.22 g/mol. C4-benzenes are found in petroleum.[1] Petrol (gasoline) can contain 5-8% C4-benzenes.[2]