MONO ETHYLENE GLYCOL
Mono ethylene glycol (also known as MEG or 1,2-ethanediol) is an organic compound with the formula C2H6O2. It is a slightly viscous liquid with a clear, colorless appearance. It is miscible with water, acetone and alcohols. It has a freezing point of -13ºC, and its boiling point is 198ºC. It has a wide range of usage in many different fields, because of its low freezing point and high boiling point.
When mixed with water, the freezing point drops further and it is used as antifreeze in radiators. It is also used in deicing agents for runways and airplanes. It is mainly used for two purposes, as a raw material in the manufacture of polyester fibers and for antifreeze formulations. Mono Ethylene glycol is primarily used in antifreeze formulations (50%) and as a raw material in the manufacture of polyesters such as polyethylene terephthalate (PET) (40%). It is preferred over glycerin in engine coolants.
The major use of mono ethylene glycol is as an antifreeze agent in the coolant in for example, automobiles and air-conditioning systems that either place the chiller or air handlers outside or must cool below the freezing temperature of water.
In geothermal heating/cooling systems, mono ethylene glycol is the fluid that transports heat through the use of a geothermal heat pump. The mono ethylene glycol either gains energy from the source (lake, ocean, water well) or dissipates heat to the sink, depending on whether the system is being used for heating or cooling.
The mixture of mono ethylene glycol with water provides additional benefits to coolant and antifreeze solutions, such as preventing corrosion and acid degradation, as well as inhibiting the growth of most microbes and fungi.
Pure mono ethylene glycol has a specific heat capacity about one half that of water. So, while providing freeze protection and an increased boiling point, mono ethylene glycol lowers the specific heat capacity of water mixtures relative to pure water. It is used as a solvent in dyes.
|CAS number||107-21-1, 104700-12-1 (13C2), 59609-67-5 (14C2), 2219-52-5 (2H), (2H)|
|PubChem||174, 21334931 (1-2H1), 16213434 (13C2), 134.462 (14C2), 10986148 (2H), (2H)|
|ChemSpider||13835235, 13835235 (13C2), 118.525 (14C2)|
|Molar mass||62.07 g mol-1|
|Density||1,1132 g / cm ³|
|Melting point||-12.9 ° C, 260 K, 9 ° C|
|Boiling point||197.3 ° C, 470 K, 387 ° F|
|Water solubility||It is miscible with water in all proportions.|
|Viscosity||1.61 × 10-2 N * s / m2|
|Flash point||111 ° C (231,8 ° F) (closed container)|
|Autoignition temperature||410 ° C (770 ° F)|
|Other names||MEG, 1-2 Ethanediol, Ethylene alcohol|
It is produced from ethylene, via the intermediate ethylene oxide (EO). In this process, glycol is produced as a result of successive reactions. Firstly ethylene oxide is produced with ethylene chlorohydrin. However, direct oxidation method, which is more practical, predominates the production of mono ethylene glycol.
In the manufacturing process, ethylene oxide (EO) is produced by oxidizing ethylene with oxygen (O) or air with silver oxide (Ag2O3) as the catalyst. Crude Ethylene Glycol is produced by hydrolysis of ethylene oxide (EO) with water under pressure.
The reaction is as shown below:
C2H4O + H2O 》HO-CH2CH2-OH
The highest yields of ethylene glycol occur at acidic or neutral pH with a large excess of water.
The water-glycol mixture formed in this process is sent to the evaporation units where the water is recovered and converted. In the production process, fractional distillation is carried out under vacuum. At this stage of production, diethylene glycol and triethylene glycol are separated.
Some manufacturers have developed processes in the production of mono ethylene glycol that enable production of products with higher purity, and eliminates some intermediate processes. It is stated that in this production reaction, by-products and the installation of handling equipment is eliminated.
It is a clear, colorless liquid. It is hazardous to the environment. Due to its liquid property, it can easily penetrate the soil. Mono ethylene glycol has a clear appearance for waxy solids.
- Boiling point is 198 °C
- Glycol formula= C2H6O2
- Melting point -13 °C
Mono ethylene glycol is miscible with water. It is highly soluble in acetone. It is very soluble in alcohol and methylene chloride. It is insoluble in fats and mineral oils. It is easily soluble in many organic solvents and aromatic hydrocarbons.
- Density approximately 1.115 g/cm3
Different types of glycols are used to reduce the freezing temperature of water due to temperature differences. When glycols are mixed with water, they reduce the freezing point of water at a certain temperature. In this way, they ensure that the system works in a healthy way. The choice of glycol to be used in the system generally depends on the system's contact with man. Ethylene glycol is not used in food manufacturers or drinking water facilities where glycol is likely to mix with food or water. Generally, mono propylene glycol is preferred.
We need to use glycol if we want to reduce the freezing temperature of water. The mixing ration of glycol with water decreases the freezing point of water. The more glycol is used, the lower is the freezing point. In other words, the resistance of water to cold weather increases that much.
- When 10% ethylene glicol and 90% water is mixed the freezing temperature of the solution will be -3.4 °C
- When 20% MEG and 80% water is mixed the freezing temperature of the solution will be -7.9 °C
- When 30% MEG and 70% water is mixed the freezing temperature of the solution will be -13.7 °C
- When 40% chemicals and 60% water is mixed the freezing temperature of the solution will be -23.5 °C
- When 50% ethylene glycol and 50% water is mixed the freezing temperature of the solution will be -36.8 °C
- When60% MEG and 40% water is mixed the freezing temperature of the solution will be -52.8 °C
The above freezing temperature values are directly related to the purity of the substance. The freezing degrees given are standard values. These values may vary 3-5% depending on the product used. The effect of ethylene glycol changes negatively over time.
Prices are directly dependent on the prices of chemicals used in the production of mono ethylene glycol. When the price of ethylene increases, so does the price of mono ethylene glycol.
The price may decrease for a short while with the increase in the number of mono ethylene glycol producers. In other words, when a new company that produces MEG is established, the price of the chemical will decrease, because it will be produced more than the glycol demand in the market.
Usage areas of mono ethylene glycol have a strong impact on prices. As the usage area increases, the market demand for glycol will increase, but since the production of ethylene glycol is constant, its prices will increase.
Mono ethylene glycol prices also depend on the MEG production process. If a low cost process is used, prices will be lower than other processes.
Chemical substances are packed in packages specified in international standards. These are sold from smaller packaging to the largest packaging or in bulk with tanker trucks. There can be 1 gram packaging, 1 ton big bag packaging, low weight drum packaging, or unpackaged bulk sales with tanker trucks.