Phenol

Phenol (carbolic acid) is an aromatic organic compound with the formula C6H5OH. It consists of a phenyl ring bearing a hydroxyl (OH) substituent. Phenol is a weak acid; in water it partially dissociates to form the phenoxide ion, with pKa around 9.9, making it more acidic than typical alcohols. It is a colorless to pale crystalline solid that has a distinctive antiseptic odor. It boils at 181.7°C and melts at 40.5°C. It is moderately soluble in water (about 8 g per 100 mL at 20°C) and is highly reactive toward electrophiles, especially at the ortho and para positions relative to the hydroxyl group.

Occurrence and production: Phenol occurs in small amounts in coal tar and is produced industrially mainly by the cumene process, in which propylene reacts with benzene to form cumene, which is oxidized to cumene hydroperoxide and then cleaved to yield phenol and acetone.

Uses: Major applications are as a chemical precursor to polymers and resins; reaction with acetone yields bisphenol A, a key monomer for polycarbonates and epoxy resins. Phenol-formaldehyde resins (Bakelite-type) are formed by condensation with formaldehyde, used in plastics, laminates, and varnishes. Phenol is also used in manufacturing detergents, herbicides, dyes, and as a disinfectant and antiseptic in some medical and laboratory settings.

Safety and environmental aspects: Phenol is caustic and toxic; skin contact can cause burns; inhalation or ingestion can be harmful. It reacts with strong oxidizers and must be handled with proper personal protective equipment and containment. It is toxic to aquatic life and should be managed to prevent environmental release.