Diethylene Glycol (abbreviated as DEG) is an important organic chemical raw material characterized by its high boiling point, strong hygroscopicity, and low volatility. Its molecular structure contains two hydroxyl groups (-OH), giving it both water solubility and compatibility with certain organic solvents. As a result, it plays a critical role in various industrial fields and daily applications. Its main functions can be categorized as follows:
1. Industrial Applications: Core Raw Material and Solvent
This is the primary application scenario for diethylene glycol, where its chemical properties make it a fundamental component of multiple industrial chains.
Raw Material for Synthetic Polymer Production
Diethylene glycol is a key raw material in the production of unsaturated polyester resins (used in fiberglass, coatings, and adhesives) and polyurethane foams/elastomers (used in furniture filling, building insulation, and shoe sole materials). Through reactions with acids and isocyanates, it forms polymer structures with specific strength and toughness.
It is also used in the synthesis of polyether polyols (a core intermediate for polyurethanes) to adjust the hardness, elasticity, and other physical properties of the final products.
High-Performance Solvent and Extraction Agent
Due to its high boiling point (approximately 245°C) and low volatility, diethylene glycol is often used as a high-boiling-point solvent in systems such as printing inks, coatings, dyes, and resins. It improves product fluidity and stability, preventing issues like coating cracking or uneven coloration caused by rapid solvent evaporation.
Additionally, it serves as an extraction agent for separating aromatic hydrocarbons from petroleum and natural gas or isolating specific organic compounds from aqueous solutions.
Lubricant and Brake Fluid Component
With its favorable viscosity and low-temperature fluidity, diethylene glycol can be used as a lubricant additive to enhance the low-temperature resistance and stability of lubricating oils. It is also an important component of automotive brake fluids (often blended with other substances), ensuring that the fluid does not boil at high temperatures or freeze at low temperatures, thereby maintaining the proper functioning of the braking system.
2. Daily and Fine Chemical Applications: Functional Auxiliary Agent
In daily-use products and fine chemicals, diethylene glycol primarily serves as a performance-modifying auxiliary agent, with strict control over its dosage due to potential health risks if used excessively.
Cosmetics and Personal Care Products: Humectant
Leveraging its strong hygroscopic properties, diethylene glycol is added as a humectant to skincare products (such as lotions and creams), toothpaste, shampoo, and other items to help retain moisture, prevent product drying or clumping, and enhance the moisturizing feel on skin and hair.
Note: International regulations impose strict limits on DEG content in cosmetics (typically ≤10%), as excessive amounts may cause skin irritation or pose health risks.
Textile and Paper Industries: Additive
In the textile industry, diethylene glycol is a component of dyeing and printing auxiliaries, improving the solubility and permeability of dyes to ensure even and durable coloring. In the paper industry, it acts as a softener or wetting agent to enhance paper flexibility and antistatic properties, reducing damage during processing.
Other Applications: Antifreeze and Dehydration
Due to its low freezing point (approximately -10.4°C), diethylene glycol is used as an antifreeze additive (often blended with ethylene glycol) in automotive coolant and industrial equipment circulating water systems to prevent freezing and equipment damage at low temperatures. It also serves as a dehydrating agent in alcohol purification or certain organic synthesis reactions to remove trace water from the system.
Precautions: Safety and Compliance
Although diethylene glycol has wide applications, it is toxic and must not be ingested (accidental ingestion may cause kidney damage, nervous system impairment, etc.). Direct skin contact should be promptly washed off. In industrial production and use, relevant safety regulations (such as ventilation and avoiding open flames) must be followed. Compliance with usage restrictions in food contact materials, cosmetics, pharmaceuticals, and other fields is essential to ensure safe application.