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Names | |||
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Preferred IUPAC name
Butanoic acid[1] | |||
Other names | |||
Identifiers | |||
3D model (JSmol)
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ChEBI |
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ChEMBL |
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ChemSpider | |||
DrugBank |
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ECHA InfoCard | 100.003.212 | ||
EC Number |
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KEGG |
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MeSH | Butyric+acid | ||
PubChem CID
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RTECS number |
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UNII |
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UN number | 2820 | ||
CompTox Dashboard (EPA)
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Properties | |||
C 3H 7COOH | |||
Molar mass | 88.106 g·mol−1 | ||
Appearance | Colorless liquid | ||
Odor | Unpleasant, similar to vomit or body odor | ||
Density | 1.135 g/cm3 (−43 °C)[2] 0.9528 g/cm3 (25 °C)[3] | ||
Melting point | −5.1 °C (22.8 °F; 268.0 K)[3] | ||
Boiling point | 163.75 °C (326.75 °F; 436.90 K)[3] | ||
Sublimes at −35 °C ΔsublH | |||
Miscible | |||
Solubility | Miscible with ethanol, ether. Slightly soluble in CCl4 | ||
log P | 0.79 | ||
Vapor pressure | 0.112 kPa (20 °C) 0.74 kPa (50 °C) 9.62 kPa (100 °C)[4] | ||
Henry's law
constant (kH) |
5.35·10−4 L·atm/mol | ||
Acidity (pKa) | 4.82 | ||
−55.10·10−6 cm3/mol | |||
Thermal conductivity | 1.46·105 W/m·K | ||
Refractive index (nD)
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1.398 (20 °C)[3] | ||
Viscosity | 1.814 cP (15 °C)[5] 1.426 cP (25 °C) | ||
Structure | |||
Monoclinic (−43 °C)[2] | |||
C2/m[2] | |||
a = 8.01 Å, b = 6.82 Å, c = 10.14 Å[2] α = 90°, β = 111.45°, γ = 90°
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0.93 D (20 °C)[5] | |||
Thermochemistry | |||
Heat capacity (C)
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178.6 J/mol·K[4] | ||
Std molar
entropy (S⦵298) |
222.2 J/mol·K[5] | ||
Std enthalpy of
formation (ΔfH⦵298) |
−533.9 kJ/mol[4] | ||
Std enthalpy of
combustion (ΔcH⦵298) |
2183.5 kJ/mol[4] | ||
Hazards | |||
GHS labelling: | |||
[6] | |||
Danger | |||
H314[6] | |||
P280, P305+P351+P338, P310[6] | |||
NFPA 704 (fire diamond) | |||
Flash point | 71 to 72 °C (160 to 162 °F; 344 to 345 K)[6] | ||
440 °C (824 °F; 713 K)[6] | |||
Explosive limits | 2.2–13.4% | ||
Lethal dose or concentration (LD, LC): | |||
LD50 (median dose)
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2000 mg/kg (oral, rat) | ||
Safety data sheet (SDS) | External MSDS | ||
Related compounds | |||
Related carboxylic acids
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Propionic acid, Pentanoic acid | ||
Related compounds
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1-Butanol Butyraldehyde Methyl butyrate | ||
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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Butyric acid (/ˈbjuːtɪrɪk/; from Ancient Greek: βούτῡρον, meaning "butter"), also known under the systematic name butanoic acid, is a straight-chain alkyl carboxylic acid with the chemical formula CH3CH2CH2CO2H. It is an oily, colorless liquid with an unpleasant odor. Isobutyric acid (2-methylpropanoic acid) is an isomer. Salts and esters of butyric acid are known as butyrates or butanoates. The acid does not occur widely in nature, but its esters are widespread. It is a common industrial chemical[7] and an important component in the mammalian gut.