What is the Difference Between Ethylene Glycol and Glycerol

The key difference between ethylene glycol and glycerol is that ethylene glycol is a polyol and a C2 diol, whereas glycerol is a C3 triol.

Both ethylene glycol and glycerol are organic compounds that can be named alcohol compounds because these compounds have -OH groups as functional groups. Moreover, both these compounds have more than one -OH group per molecule.

1. Overview and Key Difference
2. What is Ethylene Glycol
3. What is Glycerol
4. Ethylene Glycol vs Glycerol in Tabular Form
5. Summary – Ethylene Glycol vs Glycerol

What is Ethylene Glycol?

Ethylene glycol is an alcohol having the chemical formulaC₂H₆O₂. The IUPAC name of this compound is ethane-1,2-diol. At room temperature and pressure, it is a colorless, odorless liquid that is sweet tasting and viscous. This liquid is moderately toxic. The molar mass of ethylene glycol is 62 g/mol. The melting point of this liquid is -12.9°C, while the boiling point is 197.3°C. Ethylene glycol is miscible with water because it has -OH groups that are capable of forming hydrogen bonds.

There are two ways of producing ethylene glycol: industrial scale production and biological route for ethylene glycol production. In industrial-scale production, ethylene glycol is produced from ethylene. Ethylene is converted into ethylene oxide, which is then converted into ethylene glycol via the reaction between ethylene oxide and water. This reaction is catalyzed by acids or bases. If the reaction is done in a medium having a neutral pH, then the reaction mixture should be provided with heat energy. The biological route of producing ethylene glycol is via the degradation of polyethylene by gut bacteria of the caterpillar of the Greater wax moth.

What is Glycerol?

Glycerin or glycerol is a simple polyol compound having the chemical formula CHCH₂CH₂(OH)₃. This compound is colorless and odorless and occurs as a viscous liquid that has a sweet taste and is also non-toxic. The backbone of this compound is made up of lipids known as glycerides.

Glycerin has antimicrobial and antiviral properties. Therefore, it is widely used as an FDA-approved wound and burn treatment. Besides, it is useful as a bacterial culture medium and as an effective marker to measure liver disease. Apart from that, glycerin is commonly used as a sweetener in the food industry and as a humectant in pharmaceutical formulations. Since it has three hydroxyl groups, it is miscible with water and also has a hygroscopic nature.

We can get glycerin from plant and animal sources in which it occurs as triglycerides, esters of glycerol, long-chain carboxylic acids, etc. There are hydrolysis, saponification, or transesterification processes that can be used to make the glycerol and fatty acid derivative triglyceride.

What is the Difference Between Ethylene Glycol and Glycerol?

Ethylene glycol and glycerol are two important organic compounds that can be named polyols because they have more than one -OH group per molecule. The key difference between ethylene glycol and glycerol is that ethylene glycol is a polyol and a C2 diol, whereas glycerol is a C3 triol. Ethylene glycol is used as a component in antifreeze, hydraulic brake fluids, some stamp pad inks, ballpoint pens, solvents, paints, plastics, films, and cosmetics, while glycerol is used to treat constipation, improve athletic performance, for certain skin conditions, as a solvent for flavors and food colors, as a humectant, plasticizer, emollient, sweetener, etc.

The below infographic presents the differences between ethylene glycol and glycerol in tabular form for side-by-side comparison.

Summary – Ethylene Glycol vs Glycerol

Ethylene glycol is an alcohol having the chemical formulaC₂H₆O_2, while glycerol is a simple polyol compound having the chemical formula CHCH₂CH₂(OH)₃. The key difference between ethylene glycol and glycerol is that ethylene glycol is a polyol and a C2 diol, whereas glycerol is a C3 triol.

Reference:

1. “Glycerol.” An Overview | ScienceDirect Topics.

Image Courtesy:

1. “Ethylene glycol” By Sander de Jong – Own work (Public Domain) via Commons Wikimedia
2. “Glycerin Skelett” By NEUROtiker – Own work (Public Domain) via Commons Wikimedia