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Names | |||
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Preferred IUPAC name
Butanoic acid
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Other names | |||
Identifiers | |||
107-92-6 | |||
3D model (Jmol) |
Interactive image Interactive image |
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ChEBI | CHEBI:30772 | ||
ChEMBL | ChEMBL14227 | ||
ChemSpider | 259 | ||
DrugBank | DB03568 | ||
ECHA InfoCard | 100.003.212 | ||
EC Number | 203-532-3 | ||
1059 | |||
KEGG | C00246 | ||
MeSH | Butyric+acid | ||
PubChem | 264 | ||
RTECS number | ES5425000 | ||
UNII | 40UIR9Q29H | ||
UN number | 2820 | ||
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Properties | |||
C 3H 7COOH |
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Molar mass | 88.11 g·mol−1 | ||
Appearance | Colorless liquid | ||
Odor | Unpleasant and obnoxious | ||
Density | 1.135 g/cm3 (−43 °C) 0.9528 g/cm3 (25 °C) |
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Melting point | −5.1 °C (22.8 °F; 268.0 K) | ||
Boiling point | 163.75 °C (326.75 °F; 436.90 K) | ||
Sublimes at −35 °C ΔsublH |
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Miscible | |||
Solubility | Slightly soluble in CCl4 Miscible with ethanol, ether |
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log P | 0.79 | ||
Vapor pressure | 0.112 kPa (20 °C) 0.74 kPa (50 °C) 9.62 kPa (100 °C) |
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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) | ||
Viscosity | 1.814 cP (15 °C) 1.426 cP (25 °C) |
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Structure | |||
Monoclinic (−43 °C) | |||
C2/m | |||
a = 8.01 Å, b = 6.82 Å, c = 10.14 Å
α = 90°, β = 111.45°, γ = 90°
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0.93 D (20 °C) | |||
Thermochemistry | |||
178.6 J/mol·K | |||
Std molar
entropy (S |
222.2 J/mol·K | ||
Std enthalpy of
formation (ΔfH |
−533.9 kJ/mol | ||
Std enthalpy of
combustion (ΔcH |
2183.5 kJ/mol | ||
Hazards | |||
Safety data sheet | External MSDS | ||
GHS pictograms | |||
GHS signal word | Danger | ||
H314 | |||
P280, P305+351+338, P310 | |||
EU classification (DSD)
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Xn C | ||
R-phrases | R20/21/22, R34, R36/37/38 | ||
S-phrases | S26, S36, S45 | ||
NFPA 704 | |||
Flash point | 71 to 72 °C (160 to 162 °F; 344 to 345 K) | ||
440 °C (824 °F; 713 K) | |||
Explosive limits | 2.2–13.4% | ||
Lethal dose or concentration (LD, LC): | |||
LD50 (median dose)
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2000 mg/kg (oral, rat) | ||
Related compounds | |||
Other anions
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Butyrate | ||
Related Carboxylic acids
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Propionic acid Acrylic acid Succinic acid Malic acid Tartaric acid Crotonic acid Fumaric acid Pentanoic acid |
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Related compounds
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1-Butanol Butyraldehyde Methyl butyrate |
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Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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what is ?) | (|||
Infobox references | |||
Butyric acid (from Greek βούτῡρον, meaning "butter"), also known under the systematic name butanoic acid, abbreviated BTA, is a carboxylic acid with the structural formula CH3CH2CH2-COOH. Salts and esters of butyric acid are known as butyrates or butanoates. Butyric acid is found in milk, especially goat, sheep and buffalo milk, butter, parmesan cheese, and as a product of anaerobic fermentation (including in the colon and as body odor). It is also found in milk chocolate produced by the Hershey process, or added to imitate the flavour of Hershey's chocolate. Butyric acid is present in, and is the main distinctive smell of, human vomit. It has an unpleasant smell and acrid taste, with a sweetish aftertaste similar to ether. Mammals with good scent detection abilities, such as dogs, can detect it at 10 parts per billion, whereas humans can only detect it in concentrations above 10 parts per million.
Butyric acid was first observed in impure form in 1814 by the French chemist Michel Eugène Chevreul. By 1818, he had purified it sufficiently to characterize it. However, Chevreul did not publish his early research on butyric acid; instead, he deposited his findings in manuscript form with the secretary of the Academy of Sciences in Paris, France. Henri Braconnot, a French chemist, was also researching the composition of butter and was publishing his findings, and this led to disputes about priority. As early as 1815, Chevreul claimed that he had found the substance responsible for the smell of butter. By 1817, he published some of his findings regarding the properties of butyric acid and named it. However, it was not until 1823 that he presented the properties of butyric acid in detail. The name of butyric acid comes from the Latin word for butter, butyrum (or buturum), the substance in which butyric acid was first found.