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Propionic acid

Names Preferred IUPAC namePropanoic acidOther names CarboxyethaneEthanecarboxylic acidEthylformic acidMetacetonic acidMethylacetic acidC3:0 (Lipid numbers)Identifiers CAS NumberPropionic acid: 79-09-4Propionate: 72-03-73D model (JSmol)Propionic acid: Interactive imagePropionate: Interactive imageChEBIPropionic acid: CHEBI:30768ChEMBLPropionic acid: ChEMBL14021ChemSpiderPropionic acid: 1005Propionate: 94556DrugBankPropionic acid: DB03766ECHA InfoCard100.001.070EC NumberPropionic acid: 201-176-3E numberE280 (preservatives)IUPHAR/BPSPropionic acid: 1062PubChemCIDPropionic acid: 1032Propionate: 104745RTECS numberPropionic acid: UE5950000UNIIPropionic acid: JHU490RVYRPropionate: AKW5EM890CCompTox Dashboard(EPA)Propionic acid: DTXSID201058721 DTXSID8025961, DTXSID201058721InChIInChI=1S/C3H6O2/c1-2-3(4)5/h2H2,1H3,(H,4,5)Key: XBDQKXXYIPTUBI-UHFFFAOYSA-NSMILESPropionic acid: CCC(=O)OPropionate: CCC(=O)[O-]Properties Chemical formulaC3H6O2Molar mass74.079 g·mol Appearance Colorless, oily liquid OdorPungent, rancid, unpleasant Density0.98797 g/cm Melting point−20.5 °C (−4.9 °F; 252.7 K) Boiling point141.15 °C (286.07 °F; 414.30 K) SublimationconditionsSublimes at −48 °C ΔsublH = 74 kJ/mol Solubility in waterMiscible SolubilityMiscible in ethanol, ether, CHCl3log P0.33 Vapor pressure0.32 kPa (20 °C) 0.47 kPa (25 °C) 9.62 kPa (100 °C) Henry's lawconstant (kH)4.45·10 L·atm/mol Acidity (pKa) 4.88 Magnetic susceptibility (χ)−43.50·10 cm/mol Refractive index (nD)1.3843 Viscosity1.175 cP (15 °C) 1.02 cP (25 °C) 0.668 cP (60 °C) 0.495 cP (90 °C) Structure Crystal structureMonoclinic (−95 °C) Space groupP21/c Lattice constanta = 4.04 Å, b = 9.06 Å, c = 11 Åα = 90°, β = 91.25°, γ = 90°Dipole moment0.63 D (22 °C) Thermochemistry Heat capacity(C)152.8 J/mol·K Std molarentropy(S298)191 J/mol·K Std enthalpy offormation(ΔfH298)−510.8 kJ/mol Std enthalpy ofcombustion(ΔcH298)1527.3 kJ/mol Hazards Occupational safety and health (OHS/OSH): Main hazardsCorrosive GHS labelling: PictogramsSignal wordDangerHazard statementsH314Precautionary statementsP280, P305+P351+P338, P310NFPA 704 (fire diamond) 320Flash point54 °C (129 °F; 327 K) Autoignitiontemperature512 °C (954 °F; 785 K) Lethal dose or concentration (LD, LC): LD50 (median dose)1370 mg/kg (mouse, oral) NIOSH (US health exposure limits): PEL (Permissible)none REL (Recommended)TWA 10 ppm (30 mg/m) ST 15 ppm (45 mg/m) IDLH (Immediate danger)N.D. Related compounds Related Carboxylic acidsAcetic acidLactic acid3-Hydroxypropionic acidTartronic acidAcrylic acidButyric acidRelated compounds1-PropanolPropionaldehydeSodium propionatePropionic anhydrideExcept where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).Propionic acid (, from the Greek words πρῶτος : prōtos, meaning "first", and πίων : píōn, meaning "fat"; also known as propanoic acid) is a naturally occurring carboxylic acid with chemical formulaCH3CH2CO2H. It is an oily liquid with a pungent and unpleasant smell.

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