1Phenylpropene

1-phenylpropene, also known as β-methylstyrene, is an organic compound with the formula C9H10. Its structure consists of a benzene ring attached to a vinyl group that bears a methyl substituent, giving Ph-CH=CH-CH3. The double bond in this molecule enables geometric isomerism, yielding E- and Z-β-methylstyrene isomers.

As a substituted styrene, 1-phenylpropene is related to styrene (phenylethene) but carries an additional methyl group on the beta carbon of the vinyl chain. This substitution influences its reactivity and physical properties compared with unsubstituted styrene, including steric effects that can affect polymerization and addition reactions.

Reactivity and transformations of 1-phenylpropene center on its vinyl group. The compound can undergo hydrogenation of the carbon–carbon double bond to form propylbenzene (1-phenylpropane). It also participates in typical alkene reactions such as electrophilic addition and radical additions. Under suitable initiation conditions, it can polymerize to give poly(β-methylstyrene), a specialty polymer. The aryl-substituted alkene also serves as a versatile synthetic intermediate for preparing a range of downstream materials and fragrances.

Occurrences and applications vary by context, but 1-phenylpropene is primarily encountered as a synthetic building block in organic chemistry and in fragrance or polymer research. It is produced and handled in laboratory and industrial settings under standard chemical safety protocols. See also styrene and related substituted styrenes for comparative context.