What is the Difference Between Ethylene Glycol and Glycerol?

Ethylene glycol and glycerol are both organic compounds known as polyols, but they have different chemical structures and properties. The main differences between ethylene glycol and glycerol are:

1. Chemical Structure: Ethylene glycol is a C2 diol, with the chemical formula C2H6O2, while glycerol is a C3 triol, with the chemical formula CHCH2CH2(OH)3.
2. Hydroxyl Groups: Ethylene glycol has two hydroxyl groups, while glycerol has three hydroxyl groups.
3. Viscosity: Glycerol is more viscous than ethylene glycol.
4. Boiling Point: Ethylene glycol has a higher boiling point than glycerol, which is 198°C.
5. Miscibility: Both ethylene glycol and glycerol are miscible with water, but glycerol is also hygroscopic.
6. Applications: Ethylene glycol is commonly used as an antifreeze in automobile radiators and in the manufacture of polyester fiber and magnetic film used in tapes. Glycerol, on the other hand, is used in various applications such as treating constipation, improving athletic performance, skin condition treatments, as a solvent for flavors and food colors, a humectant, plasticizer, emollient, and sweetener.
7. Toxicity: Ethylene glycol is toxic, while glycerol is essentially nontoxic.

Comparative Table: Ethylene Glycol vs Glycerol

The key difference between ethylene glycol and glycerol is their chemical composition and structure. Here is a comparison table highlighting the differences between the two:

Ethylene glycol is a C2 diol with two hydroxyl groups, while glycerol is a C3 triol with three hydroxyl groups. Ethylene glycol has a lower molecular weight and viscosity compared to glycerol. It is used in various industrial applications, such as antifreeze, heat transfer fluids, and hydraulic brake fluids. On the other hand, glycerol is used as a food additive, skin moisturizer, and in pharmaceutical applications due to its lower toxicity and higher hygroscopy.