trichlorobenzene

Trichlorobenzene refers to any of several chlorinated derivatives of benzene in which three hydrogen atoms have been replaced by chlorine. Its molecular formula is C6H3Cl3. The term covers several structural isomers, of which the most commonly encountered are 1,2,3-trichlorobenzene; 1,2,4-trichlorobenzene; 1,3,4-trichlorobenzene; and 1,3,5-trichlorobenzene. The isomers differ in physical properties and reactivity, but all are relatively dense, colorless liquids or solids with limited water solubility.

Production and occurrence: Trichlorobenzenes are typically produced by controlled chlorination of chlorobenzene or benzene, often in the presence of a catalyst. Industrial shipments generally consist of mixtures of isomers; individual isomers can be separated by distillation or crystallization.

Properties: They are fairly high-boiling, nonpolar organic compounds that are poorly soluble in water and soluble in many organic solvents. Physical properties, including melting and boiling points, depend on the arrangement of chlorine atoms and the isomer. They are relatively chemically inert but can undergo further substitution under suitable conditions.

Uses: Trichlorobenzenes are used as solvents and as chemical intermediates in the manufacture of dyes, pigments, pharmaceuticals, and agrochemicals. They also serve as heat-transfer fluids in specialized applications and as building blocks for other chlorinated aromatics.

Safety and regulation: Trichlorobenzenes can be hazardous if inhaled, ingested, or absorbed through the skin. They may cause irritation and have potential effects on the nervous system and liver with prolonged exposure. They are persistent in the environment and require careful handling and disposal under applicable regulations.