SHEET /vs/ethylene-glycol-vs-propylene-glycol · COMPARISON
Ethylene glycol vs Propylene glycol: what is the difference?
How they differ
These two differ by one carbon and the difference is toxicological rather than chemical. Ethylene glycol is C2H6O2 and the body oxidises it to oxalic acid, which forms calcium oxalate crystals in the kidneys, and that is what makes antifreeze poisoning so damaging. Propylene glycol is C3H8O2 and is metabolised to lactic acid, which the body handles routinely, which is why it is permitted in food, e-liquid, and medicines. Both are sweet tasting, and the sweetness of ethylene glycol is a recurring hazard to pets and children. Many antifreeze products now use propylene glycol for exactly that reason, and some add a bitterant to the ethylene glycol kind.
Side by side
| Ethylene glycol | Propylene glycol | |
|---|---|---|
| Formula | C2H6O2 | C3H8O2 |
| Molecular weight | 62.07 g/mol | 76.09 g/mol |
| Family | Alcohols | Alcohols |
| Everyday group | Everyday chemistry | Food & flavor |
| Functional groups | Alcohols | Alcohols |
| GHS signal wordThe supplier-filed hazard label, not a statement about ordinary use. | Danger | Danger |
| Oral LD50A single acute animal measure. It ranks nothing about human safety. | 4,700 mg/kg (oral, rat) | 22,000 mg/kg (oral, rat) |
| Found in | not recorded | Processed snacks |
| CAS number | 107-21-1 | 57-55-6 |
| PubChem CID | 174 | 1030 |
Common questions
- What is the difference between Ethylene glycol and Propylene glycol?
- These two differ by one carbon and the difference is toxicological rather than chemical. Ethylene glycol is C2H6O2 and the body oxidises it to oxalic acid, which forms calcium oxalate crystals in the kidneys, and that is what makes antifreeze poisoning so damaging. Propylene glycol is C3H8O2 and is metabolised to lactic acid, which the body handles routinely, which is why it is permitted in food, e-liquid, and medicines.
- Is Ethylene glycol bigger than Propylene glycol?
- Propylene glycol is the heavier molecule, 76.09 g/mol against 62.07 g/mol for Ethylene glycol. Ethylene glycol is C2H6O2 and Propylene glycol is C3H8O2.
- Which has the lower reported LD50, Ethylene glycol or Propylene glycol?
- Ethylene glycol, at 4,700 mg/kg (oral, rat), against 22,000 mg/kg (oral, rat) for Propylene glycol. An LD50 is one acute animal measurement, and the two here were not necessarily measured in the same species, so it is a data point rather than a ranking of how dangerous either is to a person.
Read the full records: Ethylene glycol and Propylene glycol.