1methylpropylbenzene

1-methylpropylbenzene, commonly known as isopropylbenzene or cumene, is an aromatic hydrocarbon with the formula C9H12 (molecular weight about 120.19 g/mol). It consists of a benzene ring bearing a single isopropyl substituent, giving the structure C6H5–CH(CH3)2. At room temperature it is a colorless to pale liquid, with a boiling point around 150–155 °C. It is relatively hydrophobic and soluble in many organic solvents, but only sparingly soluble in water. It is flammable and should be handled with appropriate ventilation and away from sources of ignition.

Production and sources: Cumene is produced industrially by the Friedel–Crafts alkylation of benzene with propylene in the presence of a solid or liquid acid catalyst (such as AlCl3 or zeolite catalysts). The reaction is exothermic and is conducted under controlled temperatures to favor mono-alkylation.

Uses and applications: The primary industrial importance of cumene lies in its use as a precursor for phenol and acetone via the cumene process. In this sequence, cumene is oxidized to cumene hydroperoxide and then cleaved acidically to yield phenol and acetone. Beyond this, cumene serves as a nonpolar solvent and as an intermediate in various organic syntheses.

Reactions: In addition to its standard electrophilic substitution chemistry on the aromatic ring, cumene can undergo oxidation to form cumene hydroperoxide, a key intermediate in the phenol–acetone production route. It is relatively inert to mild conditions but reactive under oxidizing and strongly acidic environments.

Safety and handling: Cumene is a flammable liquid with vapors that can form explosive mixtures with air. It can cause irritation to eyes and skin and may act as a central nervous system depressant at high exposures. It should be stored in closed containers, away from heat and oxidizers.

See also: cumene process; phenol production; alkylation of benzene.