What is Ethylene Glycol?

Dhristi JEE 2022-24

Let’s have a closer look at Ethylene Glycol?

Ethylene glycol is an 'organic compound' that is extremely toxic. It is a clear, odourless, viscous liquid that has a sweet taste and boils at 388.4°F (198°C) of temperature; it is most commonly used in automotive antifreeze. A solution of  1:1 ratio of ethylene glycol and water boils at 264.2°F (129° C ) and freezes at  -34.6°C (-37° C ) serving as an excellent coolant in automotive radiators. 


Ethylene glycol finds extensive use in the industrial and commercial sectors. Ethylene glycol means the glycol which is derived from Ethylene. The chemical has both antifreeze and coolant properties. Ethylene glycol keeps your vehicle running during the winter season by not letting the engine freeze. Similarly, during the summer season, it acts as a coolant that keeps your vehicle running by preventing the engine's overheating.


Characteristics of Ethylene Glycol

Appearance: Clear, colourless, syrupy (viscous) liquid at temperature. Often coloured fluorescent yellow-green when utilised in automotive antifreeze.


Description: glycol may be a useful industrial compound found in many consumer products. Examples include antifreeze, hydraulic brakes fluids, some pad inks, ballpoint pens, solvents, paints, plastics, films, and cosmetics. It can also be a pharmaceutical vehicle. Ethylene glycol features a sweet taste and is usually ingested accidentally or intentionally. Ethylene glycol breaks down into toxic compounds within the body. Ethylene glycol and its toxic byproducts first affect the central nervous system, after that, it affects the heart, then the kidneys. Ingesting enough can cause death also. Ethylene glycol is generally odourless. 


Methods of Spreading:

Indoor Air: glycol can release into indoor air as a liquid spray (aerosol), vapour, or mist.

Water: Ethylene glycol can pollute water.

Food: Ethylene glycol can pollute food.

Outdoor Air: glycol can release into outdoor air as a liquid spray (aerosol), vapour, or mist.

Agricultural: If ethylene glycol is released as a liquid spray (aerosol) or mist, it may pollute agricultural products. If glycol is released as a vapour, it's unlikely to pollute agricultural products.


Routes of Exposure

Systemic glycol toxicity can occur through ingestion. Breathing glycol vapours may irritate eyes and lungs but is unlikely to cause systemic toxicity. Ethylene glycol doesn't absorb well through the skin so systemic toxicity is unlikely. Eye exposure may cause local adverse health effects but is unlikely to end in systemic toxicity.


Structure of Ethylene Glycol

Ethylene glycol is also known as Monoethylene glycol. It is produced when ethylene oxide chemically reacts with water. The chemical formula of Ethylene glycol is \[ C_{2}H_{6}O_{2} \]. The chemical structure of Ethylene glycol is as follows:


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What are the Uses of Ethylene Glycol?

Ethylene glycol may be a useful industrial compound found in many consumer products. Examples include antifreeze, hydraulic brakes fluids, some pad inks, ballpoint pens, solvents, paints, plastics, films, and cosmetics. It also can be a pharmaceutical vehicle.


Ethylene glycol is a viscous liquid that acts as a raw material in the manufacturing of:

  • An ingredient for making automotive coolant and antifreeze products.

  • They are extensively used in the manufacturing of polyester fibres.

  • It is a reagent used in making explosives, synthetic waxes, and alkyd resins.

  • It is also used in manufacturing fibreglass for bathtubs, bowling balls, and jet skis.

  • It is also used in making industrial coolants for ventilation, gas compressors, air-conditioning systems, heating, and ice-skating rinks.


Effects of glycol

Ethylene glycol poisoning can cause dysrhythmias and coronary failure. Glycol toxicity is characterised by an osmolal gap and acidosis with an elevated anion gap. Nephrotoxicity after glycol ingestion typically occurs 24-72 hours after acute exposure.


Chemical Dangers: Ethylene glycol generally reacts with strong oxidants and acids.


Explosion Hazards: The lower explosive (flammable) limit within the air (LEL): 3.2%. The upper explosive (flammable) limit within the air (UEL): 15.3%.


Fire Fighting Information: Ethylene glycol is combustible.

Extinguish fires using an agent suitable for the sort of surrounding fire.

Use “alcohol” foam, dry chemical, or \[CO_{2}\].

Keep water running - off out of sewers and water resources.


Initial Isolation and Protective Action Distances: 

Isolate tanks, rail cars, and tank trucks are involved in fires for 0.5 mi (800 m) altogether. Also, you can consider initial evacuation for 0.5 mi (800 m) altogether.

This agent isn't listed within the DOT ERG 2004 Table of Initial Isolation and Protective Action Distances.

Immediately isolate a glycol spill or leak area for a minimum of 330 ft (100 m) altogether.  This and similar other public safety actions are listed within the DOT ERG 2004 orange-bordered section of the guidebook (Guide 111).


Physical Dangers:

Vapours are heavier than air and can collect in poorly ventilated, low-lying, or confined areas (e.g., sewers, basements, and tanks).

In Hazardous amounts, it can develop quickly in enclosed, poorly ventilated, and low-lying areas.  excluding those areas and upwind.


What is the Molar Mass of Ethylene Glycol?

The molar mass of any chemical compound is the sum total of the atomic mass of every element that forms it. Ethylene glycol is composed of 6 hydrogens, two carbon, and two oxygen atoms. So, M (molar mass of Ethylene glycol) = 12 (carbon atomic mass) x 2 + 1 (hydrogen atomic mass) x 6 + 16 (oxygen atomic mass) x 2 = 62.07(g/mol).


Properties

  • Chemical Formula: \[ C_{2}H_{6}O_{2} \]

  • Solubility in Water: Soluble

  • Boiling Point: 387°F (197.6°C)

  • Density:
    Liquid: 1.11 at 68°F (20°C)
    Vapour: 2.14 (air = 1)

  • Flammability: Combustible liquid

  • Flashpoint: 232°F (111°C)

  • Ionisation Potential: Not 

  • Log K  Benzene-water: Not determined

  • Log Kow (estimated): -1.36

  • Melting Point: 9°F (-13°C)

  • Molecular Mass: 62.07

  • Soluble In: it is Miscible with lower aliphatic alcohols, glycerol, acetic acid, acetone, and similar ketones, aldehydes, pyridine, and similar coal tar bases. Also, it is Slightly soluble in ether. Practically insoluble in benzene and its homologs, chlorinated hydrocarbons, petroleum ether, and oils.

  • Specific Gravity: 1.11

  • Vapour Pressure: 0.06 mm Hg at 68°F (20°C)

  • Volatility: Not determined


How to Produce Ethylene Glycol?

There are different methods to produce Ethylene glycol; some of these are given below:

  1. From Ethylene

Hydroxylation of Ethylene produces Ethylene glycol. When treated with Baeyer's reagent (Cold dilute alkaline- solution of Potassium Permanganate), ethylene leads to hydroxylation at both Carbon atoms.

In this way, Ethylene glycol is produced from Ethylene.

  1. From Ethylene Oxide

Hydrolysis of ethylene oxide produces Ethylene glycol. Ethylene oxide produced by ethylene's catalytic oxidation when hydrolyzed in the presence of acid at high temperature yields Ethylene oxide.


How can Ethylene Glycol Reach the Environment?

Ethylene glycol can also enter the environment through the disposal of the products which contain it. 

  • Air: Ethylene glycol in the air will spread in about 10 days. 

  • Water and soil: Ethylene glycol in water and in the soil will break down within several days to a few weeks.

There are different ways by which Ethylene glycol disseminates into the environment.

  • Indoor Air- Ethylene glycol can be released into indoor areas polluting the air as a liquid spray (aerosol), Vapour, or mist.

  • Water- Ethylene glycol can contaminate water. It is odourless and mixes with water with ease.

  • Food- Ethylene glycol is a compound that can contaminate food.

  • Outdoor- Ethylene glycol can be released into outdoor areas polluting the air as a liquid spray (aerosol), Vapour, or mist.

  • Agriculture- If ethylene glycol is released as a liquid spray(aerosol) or mist, it may contaminate agricultural products; however, it is unlikely to contaminate the agricultural products if it is released as a vapour.


Fun Facts

  • Ethylene glycol is miscible with water.

  • It is the simplest member of the glycol family.

  • It is slightly flammable.

  • It takes about ten days for Ethylene glycol to break down in the air.

  • It vigorously reacts with oxidising agents.

  • Acrid smoke is emitted when heated to decompose. It emits irritating fumes that are hazardous.


Did You Know?

  • Ethylene glycol is too poisonous for consumption for humans or pets. It may lead to severe illness and, in extreme cases, even death. The tricky part is that ethylene glycol's taste is appealing to pets like dogs and cats. A tablespoon of ethylene glycol is fatal for your dog, while one teaspoon is enough for death for a cat. If by accident, your pet has consumed the chemical, an antidote should be given immediately.

  • Ethylene glycol is a rapid toxic substance. In contrast, propylene glycol is considered as safe as an additive for foods and medications. 

  • When the ethylene glycol is inhaled in small amounts it causes death. It is also taken intentionally for suicide attempts. Ethylene glycol is odourless, sweet liquid which is found in detergents.

  • Ethylene glycol (EG) is also a  colourless, odourless and, bitter sweet-tasting liquid. It has many household and commercial uses. Ethylene glycol is also a  “toxic alcohol”. It means that although it is chemically similar to ethanol (the active component of alcoholic beverages). Also, it is much more poisonous if consumed.


Conclusion:

Ethylene Glycol might not be a very convenient substance but has its own use. This article provides you with a bulk of content on Ethylene Glycol, its characteristics, Uses, and hazards. You can use it to prepare the topic for the purposes of your examination.

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FAQs (Frequently Asked Questions)

1. What is Ethylene Glycol Poisoning?

Consumption of ethylene glycol is very harmful as it is a poisonous chemical substance. The feeling of drinking alcohol is the first symptom after consuming Ethylene glycol. Later other symptoms emerge that include nausea, convulsions, vomiting, unconsciousness, and in extreme cases, it may result in the death of the person. However, an antidote is available to save a person's life, but the antidote must be given immediately.


It is to be noted that skin contact with a smaller quantity of Ethylene glycol will not adversely affect your health. A person working on his vehicle may accidentally touch the anti-freezing solution but will not be affected, only when Ethylene glycol ingested in large amounts may cause serious health hazards.

2. How is Ethylene Glycol Harmful to Humans?

When ethylene glycol enters the human body, it breaks down and forms chemicals. These chemicals later become crystals and start accumulating in different organs of our body. One example is the formation of crystals in the kidney. These crystals adversely affect the normal functioning of the kidney. Moreover, Ethylene glycol creates acidic chemicals in our bodies. These chemicals can change the body's acid/base balance, thus affecting the lungs, heart, and nervous system of the human body.


If human eyes are exposed to vapours of Ethylene glycol, it may irritate the eyes. Direct exposure to chemicals may cause swelling of eyelids, cornea, and inflammation of iris, conjunctiva, or cornea injury.

3. What is the Environmental Impact of Ethylene Glycol?

Ethylene glycol is an industrial chemical compound that is produced in large volumes. The compound, when it reaches the environment in large quantities, may be harmful. It usually takes ten days to break down in the air, while it takes a few weeks to break it down in soil and water. It enters the environment through different means, such as products that contain Ethylene glycol. One such place is the airports. For aircraft and runways, Ethylene glycol is a de-icing agent.


Exposure in low doses isn't harmful, while it acts as a teratogen when available in high quantities. This may result in severe congenital disabilities of the unborn child.

4. Why is ethanol used in perfumes?

Ethanol (denatured)– Alcohol is the main carrier of fragrance oils. Ethanol quickly evaporates when warmed by skin temperature. It also releases the fragrances evenly over the surface.

 

This helps to control the evaporation of the alcohol so that it does not flash off too quickly.

5. What is antifreeze used for?

It is a coloured liquid that is mixed with water to help in regulating your engine during extreme temperatures. When the temperature outside goes from hot to cold, coolant is pumped throughout the engine block to maintain an even operating temperature.

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