Monoethylene Glycol

What is Monoethylene Glycol (MEG)?

Molecular Formula (Monoethylene Glycol): C₂H₆O₂

Molecular Weight: 62.07 g/mol

Chemical Name: Monoethylene Glycol

CAS Number: 107-21-1

It is a colorless, odorless, and fluid chemical substance with a glycol structure containing two alcohol groups.

It is the most commercially traded glycol in the world.

Other Names Include:

• Ethylene Glycol
• MEG
• 1,2-Ethanediol
• 2-Hydroxyethanol
• Glycol, Ethylene
• Ethane-1,2-diol,
• 1,2-Dihydroxyethane
• Ethylene Dihydrate
• Ethylene Glycol Polymer
• Glycols, Polyethylene

How is it Produced?

It was first produced from Ethylene Oxide (EO). In this process, glycol production occurs through a series of reactions. Initially, Ethylene Oxide (EO) was produced from ethylene chlorohydrin. However, the direct oxidation method has become dominant in Monoethylene Glycol production.

In the production process, Ethylene Oxide (EO) is produced by oxidizing Ethylene with Oxygen (O) or Air with the help of a Silver Oxide (Ag₂O₃) catalyst. Crude Ethylene Glycol is produced by the hydrolysis of Ethylene Oxide (EO) with water under pressure.

The production reaction here is as follows.

Cl₂H₄O + H₂O 》HOCH₂CH₂OH

For this reaction to occur with the highest yield, a large amount of water and an acidic or neutral pH environment are required.

The water-glycol mixture formed in this process is sent to evaporation units where water is recovered and recycled. During production, fractional distillation is performed under vacuum. At this stage of production, separation from diethylene glycol and triethylene glycol is carried out.

Some manufacturers have developed processes for monoethylene glycol production that yield a higher purity product and eliminate some intermediate steps. It is stated that in this production reaction, by-products and the installation of handling equipment are eliminated.

What are its Physical and Chemical Properties?

It is a clear, colorless liquid. It has properties that are harmful to the environment. Due to its liquid nature, it can easily penetrate the soil. Monoethylene Glycol has a clear appearance for waxy solids.

Boiling point is 198 °C.

Glycol formula= C₂H₆O₂

Melting point is -13 °C.

In terms of solubility, Monoethylene Glycol is miscible with water. It is very soluble in acetone. It is very soluble in alcohol and methylene chloride. It is insoluble in fats and mineral oils.

In terms of solubility, it dissolves easily in many organic solvents and aromatic hydrocarbons.

Its density is approximately 1.115 g/cm³ .

Effect of Ethylene Glycol and Water Mixture on Freezing Point

Different types of glycols are used to lower the freezing point of water due to temperature differences. When glycols are mixed with water, they lower the freezing point of water to a certain temperature. This ensures the system operates correctly.

The choice of glycol to be used in the system generally depends on the system's contact with humans. Ethylene glycol is not used in food businesses or in systems where there is a possibility of glycol mixing with drinking water. Generally, Monopropylene Glycol is preferred.

It must be used if we want to lower the freezing point of water. The mixing ratio of glycol with water lowers the freezing point of water. The more glycol used, the lower the freezing point. This means the water's resistance to cold air increases.

Monoethylene Glycol Water Mixture and Water Freezing Point Data is as Follows

When 10% Ethylene Glycol is mixed with 90% water, the freezing point of the solution becomes -3.4 °C.

When 20% MEG is mixed with 80% water, the freezing point of the solution becomes -7.9 °C.

When 30% MEG is mixed with 70% water, the freezing point of the solution becomes -13.7 °C.

When 40% of the chemical is mixed with 60% water, the freezing point of the solution becomes -23.5 °C.

When 50% Ethylene Glycol is mixed with 50% water, the freezing point of the solution becomes -36.8 °C.

When 60% MEG is mixed with 40% water, the freezing point of the solution becomes -52.8 °C.

The freezing point values above are directly related to its purity. The given freezing points are standard values. These values may vary in the range of -3-5% depending on the product used. The effect of Ethylene Glycol changes negatively over time.

What are the Usage Areas of Monoethylene Glycol?

• Among the usage areas of Monoethylene Glycol, it is most commonly used in substances such as polyester resins, fibers, containers, and films.
• It is used as an intermediate in the production of plastic materials. In this application, Ethylene Glycol is used for its plasticizing properties. Resin esters (Adhesives, lacquers, and enamels)
• Snow can accumulate on the wings and top of aircraft. This accumulation can cause corrosion. Antifreeze compounds are used both to prevent this corrosion and to inhibit icing. In these antifreezes, it is used as a Glycol along with Diethylene Glycol.
• Used in the manufacture of alkyd-type resins (Synthetic Rubbers and surface coatings).
• Used in the glycolysis reaction during the recycling process of polyurethane foams.
• Its use as a solvent binder is one of its most important applications. It is used to provide stabilizing properties against gel formation, to obtain different indicators at the freezing point, and for draining liquids.
• It is used in the manufacture of heat transfer fluids. These include: Gas compressors, heating ventilation, air conditioning, process coolers, and ice rinks.
• It is used in the manufacture of automotive antifreezes used in all weather conditions. It is used in the manufacture of coolants.
• It is used in water-based formulations. These include: adhesives, latex paints, and asphalt emulsions.
• It is a natural humectant. Therefore, its moisturizing property is also utilized. Areas where it is used as a humectant include textile fibers, paper, leather, adhesives, and the glue industry.
• It is used as a solvent in areas where it is used as a chemical intermediate.
• It is used inside engine blocks produced with sand cores.
• It is used together with wetting agents (Surfactants) to reduce foam in dispersion mixtures.
• In the manufacture of surfaces like tennis courts and running tracks, an adaptation with monoethylene glycol is made to ensure better penetration and adhesion of the barrier layer and the top layer to the gel layer.
• It is used to prevent corrosion in Aluminum and Aluminum alloys used at high temperatures.
• It is used in the cooling systems (Chiller) of analytical devices. If MEG is not used, errors occur in the intensity readings.
• Used together with 1,3-Propylene Glycol, it prevents ice formation on aircraft surfaces down to low temperatures. An inhibitor is also used in this application.
• It is used as a foaming agent in the flotation stage in mining sites. The mineralogy of the substance to be floated is important in this application.
• Washing chemicals are produced to remove many types of stains found on fabrics and upholstery. It is used in these washing chemicals.

What Factors Affect its Price?

Prices are directly dependent on the prices of the chemicals used in the production of Monoethylene glycol. As the price of ethylene increases, the price of Monoethylene Glycol will also increase.

An increase in the number of Monoethylene glycol producers will cause a short-term decrease. That is, when a new company that produces MEG is established, the price of this chemical will decrease. This is because production will exceed the demand for glycol in the market.

The usage areas of Monoethylene glycol have a very high impact on its price. As the usage area increases, the price will increase. This is because the demand for glycol in the market will increase, but since Ethylene glycol production is constant, prices will rise.

Monoethylene glycol prices also depend on the process used for MEG production. If a low-cost process is used, the prices will be lower compared to other systems.