Indene

Indene is an organic compound with the chemical formula C9H8. It is a bicyclic hydrocarbon consisting of a benzene ring fused to a cyclopentadiene ring. Indene is a colorless liquid at room temperature with a characteristic odor. It is a relatively unstable compound due to the presence of the cyclopentadiene ring, which can undergo polymerization and other reactions. Indene occurs naturally in coal tar and is also produced during petroleum refining processes.

Industrially, indene is a valuable precursor for the synthesis of various polymers and chemicals. It can be polymerized to form polyindene, which has applications in adhesives and coatings. Indene derivatives are also used in the production of resins, pharmaceuticals, and fragrances. The reactivity of the double bond in the cyclopentadiene ring allows for a wide range of chemical transformations, including Diels-Alder reactions and functionalization of the aromatic ring. Its presence in complex mixtures like coal tar necessitates separation and purification techniques to obtain pure indene for specific applications.