C9H12

C9H12 is the molecular formula associated with a number of hydrocarbon isomers. The most common structures are aromatic, consisting of a benzene ring bearing a C3 hydrocarbon substituent. The two principal isomers are cumene (isopropylbenzene) and n-propylbenzene (1-phenylpropane). Cumene has the structure C6H5-CH(CH3)2, while n-propylbenzene is C6H5-CH2-CH2-CH3. Both satisfy the formula C9H12 and feature four degrees of unsaturation, reflecting the benzene ring.

There are other possible, less common C9H12 structures as well, but these benzene derivatives are the main representatives in chemical literature. The molecular weight is about 120.19 g/mol. Physical properties vary among isomers; both are colorless liquids at room temperature and are soluble in organic solvents but only sparingly soluble in water.

Industrial relevance centers on cumene, a major feedstock for the production of phenol and acetone via the cumene process. n-Propylbenzene serves as a chemical intermediate and solvent in various organic syntheses. These compounds are flammable and should be handled with appropriate safety measures. In analytical contexts, C9H12 exemplifies how a single molecular formula can correspond to multiple structural isomers, illustrating the need to specify connectivity when discussing properties or reactions.