Dimetyylitereftalaatin

Dimetyylitereftalaatin, also known as dimethyl terephthalate (DMT), is the dimethyl ester of terephthalic acid. Its chemical formula is C10H10O4. It is a colorless crystalline solid used as a chemical intermediate in polymer production and as a building block in various polyester syntheses.

Production of DMT typically occurs by esterification of terephthalic acid with methanol in the presence of an acid catalyst at elevated temperature, yielding dimethyl terephthalate and water. Another common route involves methanolysis of terephthalic acid or, in some processes, conversion of p-xylene to terephthalic acid followed by esterification to DMT. Purification is usually accomplished by distillation or crystallization to achieve the desired purity for downstream applications.

Uses and role in polymers are central to DMT. It is a key monomer feedstock for the production of polyethylene terephthalate (PET) via transesterification with ethylene glycol to form bis(2-hydroxyethyl) terephthalate (BHET), which subsequently polymerizes to PET. DMT is also used to manufacture other polyesters and polyester resins, and functions as an intermediate in various chemical syntheses.

Handling and safety considerations include avoiding inhalation of dust or vapors and minimizing skin and eye contact. Appropriate personal protective equipment should be used, and processing should occur in well-ventilated areas. Storage should be in closed, dry containers under suitable temperatures, with standard precautions for chemical intermediates.