Indene

Chemical properties

Yellow green clear liquid

The Uses of Indene

Preparation of coumarone-indene resins, intermediate.

The Uses of Indene

Preparation of coumarone-indene resins

The Uses of Indene

1H-Indene is a building block that has been used in the synthesis of isatins. It was used in the synthesis of new C60 derivative, indene-C60 bisadduct. It was used in preparing polyindene by the controlled cationic polymerization initiated with cumyl methyl ether/TiCl4 in CH2Cl2.

Definition

indene: A colourless flammable hydrocarbon,C₉H₈; r.d. 0.996; m.p.–1.8°C; b.p. 182.6°C. Indene is anaromatic hydrocarbon with a five-memberedring fused to a benzenering. It is present in coal tar and isused as a solvent and raw materialfor making other organic compounds.

Synthesis Reference(s)

Tetrahedron Letters, 18, p. 49, 1977 DOI: 10.1016/S0040-4039(01)92547-X

General Description

A colorless liquid derived from coal tar. Fp: -2°C; bp:182°C. Density 0.997 g cm-3. Insoluble in water but soluble in organic solvents.

Reactivity Profile

Indene is combustible (flash point between 140°F and 200°F). Polymerizes and oxidizes on standing in the air. This reaction is accelerated by heating, acids, and catalysts, including peroxides. Has exploded during nitration with a mixture of H2SO4 and HNO3.

Hazard

Toxic by inhalation.

Health Hazard

Indene is expected to be an irritant of the mucous membranes.

Purification Methods

Shake indene with 6M HCl for 24hours (to remove basic nitrogenous material), then reflux it with 40% NaOH for 2hours (to remove benzonitrile). Fractionally distil, then fractionally crystallise it by partial freezing. The higher-melting portion is converted to its sodium salt by adding a quarter of its weight of sodamide under nitrogen and stirring for 3hours at 120o. Unreacted organic material is distilled off at 120o/1mm. The sodium salts are hydrolysed with water, and the organic fraction is separated by steam disillation, followed by fractional distillation. Before use, the distillate is passed, under nitrogen, through a column of activated silica gel. It turns yellow in air as it readily oxidizes and polymerises. [Russell J Am Chem Soc 78 1041 1956, Beilstein 5 IV 1532.]