Tereftaalihappo

Tereftaalihappo, known in English as terephthalic acid, is an aromatic dicarboxylic acid used primarily as a monomer in polyester polymers. Its chemical formula is C8H6O4 and its IUPAC name is benzene-1,4-dicarboxylic acid. It appears as a white to off-white crystalline solid and has a high melting point. It is sparingly soluble in water and more soluble in certain organic solvents.

Industrial production of terephthalic acid is based on the catalytic oxidation of para-xylene with air. The process often uses a solvent system and metal catalysts (commonly cobalt and manganese) to facilitate oxidation, producing crude terephthalic acid that is subsequently purified by crystallization to high purity. The refining steps may include removal of solvents and byproducts before the acid is isolated as a solid.

The principal use of terephthalic acid is as a monomer for the production of polyethylene terephthalate (PET), a widely used polymer in bottles, food packaging, and textiles. It is also employed in the manufacture of other polyesters, resins, and coatings, as well as in some dye and pigment applications. Dimethyl terephthalate (DMT) and other derivatives serve as alternative intermediates in polyester production.

Safety and handling guidelines for terephthalic acid emphasize basic laboratory hygiene; it can cause irritation to the skin, eyes, and respiratory tract upon exposure. It should be handled with appropriate personal protection, and waste should be disposed of according to local environmental regulations.