Ethylene glycol (EG), with the chemical formula C₂H₆O₂, is a colorless, odorless, sweet-tasting viscous liquid. As an important organic chemical raw material, its uses span industrial, consumer, medical, and electronics applications. The following provides a detailed analysis of its core applications, technical characteristics, and industry trends.
Industrial Applications: The Versatile Workhorse
Core Raw Material for Polyester Materials
Ethylene glycol reacts with terephthalic acid (PTA) to produce polyethylene terephthalate (PET), the foundation of polyester fibers, plastic bottles, and films. In 2024, global polyester fiber production reached 60.6 million tons, with China accounting for nearly 50% of global consumption. For example, bottle-grade PET is used for mineral water bottles, while fiber-grade PET is a major component of clothing fabrics, offering far superior wear resistance and wrinkle resistance compared to natural fibers.
Core Heat Transfer Fluid for Industrial Cooling Systems
Ethylene glycol aqueous solutions are widely used for automobile engine cooling, chemical reactor temperature control, and data center liquid cooling systems due to their low freezing point (50% concentration solution freezes at -33°C) and high boiling point (108°C). For example, some new material enterprises use -30°C ethylene glycol units to precisely control polymerization reaction temperatures, while high-density server immersion cooling technology also relies on its efficient heat dissipation characteristics.
Key Additive for Polyurethane and Coatings
In polyurethane synthesis, ethylene glycol participates as a polyol to manufacture furniture sponges, car seats, and building insulation materials. In the coatings industry, its addition ratio is typically 5%-15%, which can adjust viscosity, improve adhesion, and enhance coating gloss and durability. For example, in water-based coatings, ethylene glycol can prevent excessively fast drying to ensure uniform film formation.
Consumer and Daily Chemicals: From Antifreeze to Moisturizer
Mainstream Choice for Automotive Antifreeze
Ethylene glycol accounts for more than 90% of global water-based antifreeze formulations. By lowering the freezing point and raising the boiling point, it protects engines. For example, a 58% concentration ethylene glycol aqueous solution has a freezing point as low as -48°C, and also features anti-corrosion and anti-scaling properties. Although its toxicity is relatively high, adding bittering agents and bright pigments (such as red, green) can effectively reduce the risk of accidental ingestion.
Moisturizing Agent in Cosmetics and Personal Care
Due to its hygroscopic properties, ethylene glycol is used as a moisturizer in skincare products, commonly found in face creams, lotions, and toothpaste, with typical addition amounts of 5%-15%. For example, when combined with glycerin, it can improve product texture while preventing dry skin. However, due to potential irritation, it has gradually been replaced by safer ingredients such as propylene glycol in recent years.
High-End Manufacturing: Precision Applications in Electronics and Medicine
Ultra-High Purity Solvent for Semiconductor Manufacturing
Electronic-grade ethylene glycol must meet SEMI C12 standards (metal ions <100 ppt) and is used for wafer cleaning, etching, and circuit board production. For example, in chip manufacturing, its ultra-clean characteristics can prevent particle contamination and ensure device yield. The global electronic-grade ethylene glycol market is expected to reach USD 7.587 billion by 2029, with a CAGR of 5.63%.
Multifaceted Assistant in the Medical Field
- Solvent and carrier: Ethylene glycol can dissolve poorly soluble drugs to improve bioavailability, commonly found in oral solutions and injections.
- Cryoprotectant: In medical device preservation, its low freezing point characteristics can prevent equipment from freezing damage at low temperatures.
- Drug synthesis intermediate: Used in the production of fungicides such as penconazole and hymexazol.
Safety and Sustainable Development
Ethylene glycol ingestion can cause kidney failure. Emergency treatment requires gastric lavage, hemodialysis, and use of antidotes (such as ethanol, fomepizole) to inhibit metabolism. In industrial applications, workplace concentrations must be strictly controlled (PC-TWA 20 mg/m³), and protective equipment must be provided.
China's new national standard GB 29743.1-2022 restricts additives such as phosphates and nitrites, promoting the development of low-toxicity, biodegradable products. Propylene glycol is gradually replacing ethylene glycol in food contact and medical applications due to its better biodegradability. Meanwhile, coal-to-ethylene glycol technology mitigates supply-demand contradictions through clean conversion of coal resources.
Conclusion
With its unique physicochemical properties, ethylene glycol has become an indispensable basic material in modern industry. From polyester fibers to semiconductor manufacturing, from automotive antifreeze to pharmaceutical carriers, its applications run through the upstream and downstream of industrial chains. In the future, as environmental regulations become stricter and technology advances, ethylene glycol will continue to break through in improving performance, reducing toxicity, and developing bio-based alternatives, providing more efficient and sustainable solutions for various industries.
