[Chemical Knowledge]：The nature, use, upstream and downstream raw materials, storage methods of dibasic acid esters, what is the use of dibasic acid esters?

Properties of dibasic acid esters

A dibasic acid ester, also known as a dicarboxylic acid ester, is a compound formed by the reaction of a dicarboxylic acid and an alcohol. They usually have the following characteristics:

Physical properties: the two basic acid ester is mostly colorless to light yellow liquid, with a certain viscosity and good solubility. Their boiling and melting points vary depending on the molecular structure. Common dibasic esters, such as dimethyl terephthalate (DMT), are solid at room temperature, while diethyl adipate (DEDA) is liquid.

Chemical properties: dibasic acid ester has high chemical stability and is not easy to hydrolyze, especially under neutral and acidic conditions. Their chemical reactivity is mainly reflected in the ester group, which can occur transesterification reaction, hydrogenation reduction reaction and so on. The dibasic esters can undergo pyrolysis and polymerization at elevated temperatures or in the presence of a catalyst.

Dibasic acid ester use

Dibasic acid esters are widely used in many industrial fields, mainly including the following aspects:

Plastics and resins: dibasic acid esters are important raw materials for the production of polyester resins. Polyester resins can be used to make plastic bottles, fibers and films, etc. Dimethyl terephthalate (DMT) and polyethylene terephthalate (PET) synthesized from ethylene glycol are the most common examples.

Coatings and Inks: Dibasic acid esters are often used as components of coatings and inks due to their good film-forming properties and solubility. They impart excellent mechanical properties and chemical resistance to the coating.

Plasticizers: Certain dibasic acid esters such as dioctyl adipate (DOA) are widely used as plasticizers to improve the flexibility and ductility of polymeric materials, especially in polyvinyl chloride (PVC) products.

Lubricants: Some high molecular weight dibasic acid esters, such as diisooctyl sebacate (DOS), are used as components of high temperature lubricating oils due to their excellent lubricity and thermal stability.

Dibasic acid ester upstream and downstream raw materials

The production of dibasic acid esters involves multiple upstream and downstream feedstocks:

Upstream Feedstocks The main upstream feedstocks for dibasic acid esters include dicarboxylic acids and alcohols. Dicarboxylic acids such as adipic acid, terephthalic acid and the like are usually produced by chemical synthesis or fermentation. Alcoholic raw materials such as methanol, ethanol, isopropanol, etc., are mainly produced by the petrochemical industry.

Downstream products: The downstream products of dibasic acid esters are mainly various polyester materials, plasticizers, coatings and inks. The dibasic acid esters can be further processed into other fine chemical products, such as high-performance lubricants and special chemical reagents.

Binary acid ester production process

The production of dibasic acid esters is generally carried out by an esterification reaction, which is usually carried out in the presence of an acid catalyst (e. g. sulfuric acid, p-toluenesulfonic acid). The following are typical production process steps:

Esterification reaction: the dicarboxylic acid and alcohol are mixed in a certain proportion, after adding the catalyst, the reaction kettle is heated to an appropriate temperature (usually 120-180 ℃), and the esterification reaction is carried out. The water formed during the reaction is removed by azeotropic distillation or vacuum distillation to drive the reaction in the direction of ester formation.

Post- treatment: After the esterification reaction is completed, the reaction mixture is purified by neutralization, washing, distillation and other steps to obtain a pure dibasic acid ester product.

Refining and packaging: After preliminary purification, the dibasic acid ester needs to be further refined, usually using vacuum distillation or membrane separation technology. The final product is also subject to quality testing before packaging to ensure that its purity and performance meet the requirements.

Dibasic acid ester storage method

The storage method of dibasic acid ester needs to consider its chemical stability and physical characteristics:

Storage conditions: The dibasic acid ester should be stored in a cool, dry, well-ventilated warehouse, avoiding direct sunlight and high temperature environment. Since some dibasic acid esters may decompose or polymerize at high temperatures, the storage temperature is generally controlled at 15-25°C.

Container requirements: The dibasic acid esters are usually stored in sealed metal or plastic containers. The container material must be resistant to chemical corrosion and comply with relevant safety standards. For volatile dibasic acid esters, it is recommended to use pressure-resistant containers to prevent volatilization and leakage.

Safety measures: the warehouse should be equipped with good ventilation equipment and fire-fighting facilities, and the storage area should be posted with obvious dangerous goods identification. Personnel shall wear protective gloves and goggles during operation and handling to prevent skin contact and eye irritation.

Conclusion

As important chemical intermediates and functional materials, dibasic acid esters have broad application prospects. Its production involves complex chemical reactions and fine process control, requiring strict quality management and safety measures. With the advancement of technology and the growth of market demand, the application field of dibasic acid esters will continue to expand and become an indispensable part of the modern chemical industry.