| Boiling Point | 141°C (lit.) |
| Melting Point | −24 to −23°C (lit.) |
| Density | 0.993 g/mL at 25°C (lit.) |
| Color | Colorless |
| Linear Formula | CH3CH2COOH |
| Formula Weight | 74.08 |
| Physical Form | Clear liquid |
| Chemical Name or Material | Propionic Acid |
| UN Number | UN3463 |
| Molecular Weight | 74.08 g/mol |
| SMILES String | CCC(O)=O |
| Refractive Index | n20/D 1.386 (lit.) |
| CAS Number | 79-09-4 |
| EC Number | 201-176-3 |
| NACRES | NA.21 |
| PubChem Substance ID | 24865136 |
| UNSPSC Code | 12352100 |
| MDL Number | MFCD00002756 |
| InChI | 1S/C3H6O2/c1-2-3(4)5/h2H2,1H3,(H,4,5) |
| InChI Key | XBDQKXXYIPTUBI-UHFFFAOYSA-N |
| Beilstein/REAXYS Number | 506071 |
| Quality Level | 200 |
| Reference Grade | ACS reagent, ≥99.5% |
Propionic Acid is a three-carbon short-chain fatty acid, naturally produced during fermentation of undigested food by gut microbiota and manufactured industrially via hydrocarboxylation of ethylene. Its combination of antimicrobial (specifically mold-inhibiting) activity and relatively low cost has made it one of the most widely used food and feed preservatives.
Propionic acid’s largest use is as a mold-inhibiting preservative in food products (particularly baked goods) and animal feed, where it’s valued for being stable, inexpensive, and effective at low concentrations. In industrial and synthesis chemistry, it’s a raw material for producing propionate esters and salts, and it’s used in select research applications, including limestone-based CO2 uptake studies.
