Difference between Ethylene Glycol and Diethylene Glycol

In the chemical industry, ethylene glycol (Ethylene Glycol,EG) and diethylene glycol (Diethylene Glycol,DEG) are two important chemicals. They have many similarities in production, application and performance, but there are also significant differences. Understanding these differences is critical for chemical engineers, researchers, and product developers.

1. Definition and Structure

1. Ethylene Glycol (EG)

Ethylene glycol is a glycol with the formula C2H6O2 and a structure containing two hydroxyl groups (-OH) and an ethyl group (-CH2CH3) and a methyl group (-CH3). It is a colorless, odorless, non-toxic liquid with a boiling point of 197°C and a density of 1.114g/cm³.

Ethylene glycol is a simple glycol, widely used in the manufacture of polyester, plastic, rubber and other materials. It is also one of the important sources of biofuels, because ethylene glycol can be produced by fermentation of glucose and become the raw material for the preparation of ethanol fuel.

2. Diethylene Glycol (DEG)

The molecular formula of diethylene glycol is C4H10O2, and the structure contains two ethylene glycol molecules connected by esterification. It is a colorless, odorless, non-toxic liquid with a boiling point of 200-210°C and a density of 1.189g/cm³.

Diethylene glycol is more complex than ethylene glycol, and it is mainly used in chemical applications to make polymer materials, such as polyesters, plastics and coatings. Due to its more complex structure, diethylene glycol has higher performance and stability in certain specific applications.

2. of Chemical and Physical Properties

1. Purity and purification

The purity of ethylene glycol is relatively easy to control, and its purity is usually above 99%. Because the molecular structure of diethylene glycol is more complex, the purity control is relatively difficult, and it is easy to be contaminated by impurities.

2. Melting point and boiling point

Ethylene glycol has a melting point of -6°C and a boiling point of 197°C, while diethylene glycol has a melting point of -8°C and a boiling point of 200-210°C. The boiling point of diethylene glycol is slightly higher, but the melting point is also slightly lower, which will affect its application in high or low temperature environments.

3. Electrical and thermal conductivity

Ethylene glycol is an excellent conductive liquid, its conductivity in the pure state of 0.143 S/m. Diethylene glycol is slightly less conductive, but its thermal conductivity is good, which may affect its use in certain heat exchange equipment.

3. Application Fields and Advantages and Disadvantages

1. Industrial application

Ethylene glycol is widely used in polyester production, plastic manufacturing and rubber processing. Its simple structure makes it easy to process and control, low cost, and wide range of applications.

Diethylene glycol is mainly used in the production of more complex polymer materials, such as high-performance plastics, coatings and rubber. Due to its more complex molecular structure, diethylene glycol has advantages in certain specific performance indicators, such as higher heat resistance or better processing stability.

2. Bio-based applications

Ethylene glycol can be produced by fermentation of glucose, which has good bio-based characteristics and is suitable for biofuel and green chemical industries.

Bio-based sources of diethylene glycol are relatively difficult, and their complex chemical structure limits their use in bio-based applications.

3. Environmental impact

Ethylene glycol may produce certain environmental pollution in the production process, especially in the process of synthetic fibers and plastics.

The production of diethylene glycol has less impact on the environment, and its complex molecular structure gives it an advantage in some environmentally friendly materials.

4. selection and application recommendations

When selecting ethylene glycol and diethylene glycol, it is necessary to consider comprehensively according to specific application scenarios. If a simple, low-cost polymer material is required, ethylene glycol is the ideal choice. If higher performance and more complex molecular structure of the material is required, diethylene glycol is more suitable.

Ethylene glycol and diethylene glycol have their own characteristics in the chemical industry. Understanding their differences and advantages and disadvantages is of great significance for improving production efficiency, optimizing processes and reducing costs. professionals for the chemical industry should carefully evaluate the specific requirements of their processes to select the most appropriate raw materials and processes.