WikipediaCAS 79-09-4
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| Simplified skeletal formula | Full structural formula |
|---|---|
| Names | |
| Preferred IUPAC name | Propanoic acid |
| Lipid numbers | Carboxyethane / Ethanecarboxylic acid / Ethylformic acid / Metacetonic acid / Methylacetic acid / C3:0 ( Lipid numbers ) |
| Identifiers | |
| CAS Number | Propionic acid: 79-09-4 Y · Propionate: 72-03-7 |
| EC Number | Propionic acid: 201-176-3 |
| E number | E280 (preservatives) |
| IUPHAR/BPS | Propionic acid: 1062 |
| PubChem CID | Propionic acid: 1032 · Propionate: 104745 |
| RTECS number | Propionic acid: UE5950000 |
| SMILES | Propionic acid: CCC(=O)O · Propionate: CCC(=O)[O-] |
| Properties | |
| Chemical formula | C 3 H 6 O 2 |
| Molar mass | 74.079 g · mol−1 |
| Appearance | Colorless, oily liquid |
| Odor | Pungent, rancid, unpleasant |
| Density | 0.98797 g/cm3 |
| Melting point | −20.5 °C (−4.9 °F; 252.7 K) |
| Boiling point | 141.15 °C (286.07 °F; 414.30 K) |
| Sublimation / conditions | Sublimes at −48 °C / Δsubl H o = 74 kJ/mol |
| Solubility in water | Miscible |
| Solubility | Miscible in ethanol , ether , CHCl / 3 |
| log P | 0.33 |
| Vapor pressure | 0.32 kPa (20 °C) / 0.47 kPa (25 °C) / 9.62 kPa (100 °C) |
| Henry's law / constant ( k H) | 4.45 · 10−4 L · atm/mol |
| Acidity (p K a) | 4.88 |
| Magnetic susceptibility (χ) | −43.50 · 10−6 cm3/mol |
| Refractive index ( n D) | 1.3843 |
| Viscosity | 1.175 c P (15 °C) / 1.02 cP (25 °C) / 0.668 cP (60 °C) / 0.495 cP (90 °C) |
| Structure | |
| Crystal structure | Monoclinic (−95 °C) |
| Space group | P21/c |
| Lattice constant | a = 4.04 Å, b = 9.06 Å, c = 11 Å · α = 90°, β = 91.25°, γ = 90° |
| Dipole moment | 0.63 D (22 °C) |
| Thermochemistry | |
| Heat capacity ( C ) | 152.8 J/mol · K |
| Std molar / entropy ( S ⦵298) | 191 J/mol · K |
| Std enthalpy of / formation (Δf H ⦵298) | −510.8 kJ/mol |
| Std enthalpy of / combustion (Δc H ⦵298) | 1527.3 kJ/mol |
| Hazards | |
| Main hazards | Corrosive |
| Signal word | Danger |
| Hazard statements | H314 |
| Precautionary statements | P280 , P305+P351+P338 , P310 |
| Flash point | 54 °C (129 °F; 327 K) |
| Autoignition / temperature | 512 °C (954 °F; 785 K) |
| LD50 ( median dose ) | 1370 mg/kg (mouse, oral) |
Wikipedia
Carboxylic acid with chemical formula CH3CH2CO2H
Propionic acid is a naturally occurring carboxylic acid with chemical formula CH3CH2CO2H. It is an oily liquid with a pungent and unpleasant smell. The anion CH3CH2CO−2 as well as the salts and esters of propionic acid are known as propionates or propanoates. Propionic acid is the third simplest carboxylic acid, with the first two being formic acid and acetic acid.