What Is Dimethyl Terephthalate?
Dimethyl terephthalate (DMT) is an organic compound in the form of a white crystalline powder. Its IUPAC name is dimethyl benzene-1,4-dicarboxylate, and it is commonly known as terephthalic acid methyl ester, among other names.
Uses of Dimethyl Terephthalate
DMT serves as a key raw material in producing polyethylene terephthalate (PET), polytrimethylene terephthalate (PTT), and polybutylene terephthalate (PBT) resins. PET is extensively used in polyester fibers, films, and bottles. PTT, derived from plant sources, offers excellent elasticity and is used in carpets and car seats. PBT is valued for its moldability and electrical properties, making it ideal for automotive parts and electronic components.
Properties of Dimethyl Terephthalate
DMT has the chemical formula C10H10O4, with a molecular weight of 194.18 and CAS number 120-61-6. It melts at 140-142°C and boils at 288°C. This odorless compound is soluble in acetone, has limited solubility in ether and ethanol, and is virtually insoluble in water.
Other Information on Dimethyl Terephthalate
Dimethyl Terephthalate Manufacturing Process
The primary method for producing DMT is through the Bitten-Hercules process. This process involves esterifying an oxidation reaction mixture from paraxylene and methyl p-toluylate with methanol under high temperature and pressure. Alternatively, DMT can be synthesized by esterifying terephthalic acid with methanol, allowing the use of lower-purity terephthalic acid.
Regulatory Information
DMT is regulated under various laws due to environmental and health considerations. It is classified as a Class 1 Designated Chemical Substance, reflecting its potential impact as a hazardous air pollutant.
Precautions for Handling and Storage
To ensure safety, avoid contact with strong oxidizers, acids, and nitrates, as DMT poses a risk of respiratory irritation. Use protective equipment and store DMT in cool, well-ventilated areas away from direct sunlight and ignition sources.