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Source:Transform the World with Simplicity
PTA (terephthalic acid) is an important organic chemical raw material, which is widely used in the production of polyester (PET) and other products. This article will detail the nature, use and production process of PTA.
1. the properties of PTA
PTA is a white crystalline powder with low toxicity, flammability and corrosiveness. Its molecular structure contains carboxyl group and benzene ring, which makes PTA have high chemical stability and thermal stability. In addition, PTA has good water solubility and can be dissolved in some organic solvents.
2. the use of PTA
1. Production of polyester (PET)
The main use of PTA is as a raw material for the production of polyester (PET). Polyester is a polymer compound with excellent physical and chemical properties and is widely used in the production of fibers, films, bottles and cans. In polyester production, PTA and ethylene glycol (EG) are esterified to produce diethyl terephthalate (BHET), which is then polycondensed to produce polyester.
2. Production of other chemical products
In addition to the production of polyester, PTA can also be used to produce other chemical products, such as dimethyl terephthalate (DMT), terephthalic anhydride (TPA), etc. These products are also widely used in chemical, pharmaceutical, pesticide and other fields.
3. PTA production process
PTA production process mainly has two kinds of oxidation and hydrogenation. Among them, oxidation method is a commonly used method in industrial production at present, and its process flow is as follows:
1. Oxidation of p-xylene (PX) to generate p-xylene acid (TA)
2. Hydrogenation of p-xylene acid to generate PTA
In oxidation reaction, the commonly used oxidant is acetic acid or acetic acid, the reaction temperature is generally 180-200 ℃, and the pressure is between 1.0-2.0MPa. The hydrogenation reaction is under the action of high temperature, high pressure and catalyst, the hydrogenation of TA to PTA.
4. PTA market prospects
With the continuous development of domestic and foreign economies and the improvement of people's living standards, the demand for polyester products is increasing, so the PTA market prospects are very broad. In the future, with the continuous progress of technology and the improvement of environmental protection requirements, the production process of PTA will be more environmentally friendly and efficient, and the product quality will be further improved.
In conclusion, as an important organic chemical raw material, PTA has broad application prospects in the field of chemical production raw materials.