Names | |
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Preferred IUPAC name
Phenoxyacetic acid | |
Identifiers | |
3D model (JSmol)
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907949 | |
ChEBI | |
ChEMBL | |
ChemSpider | |
ECHA InfoCard | 100.004.143 |
EC Number |
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142730 | |
KEGG | |
PubChem CID
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UNII | |
UN number | 3347 |
CompTox Dashboard (EPA)
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Properties | |
C8H8O3 | |
Molar mass | 152.15 g/mol |
Appearance | White solid or tan powder |
Odor | Sweet and sour |
Melting point | 98–99 °C (208–210 °F; 371–372 K) |
log P | 1.48 |
Acidity (pKa) | 3.7 |
Hazards | |
GHS labelling: | |
Warning | |
H302, H315, H319, H335 | |
P261, P264, P270, P271, P280, P301+P312, P302+P352, P304+P340, P305+P351+P338, P312, P321, P330, P332+P313, P337+P313, P362, P403+P233, P405, P501 | |
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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Phenoxyacetic acid, POA, is a white solid with the formula of C8H8O3.[1][2] Although not itself usefully active as an herbicide, it forms the part-structure of many phenoxy herbicide derivatives including MCPA and 2,4-D.
Phenoxyacetic acid is an O-phenyl derivative of glycolic acid. It is both a monocarboxylic acid and an aryl ether. Its preparation from sodium phenolate and sodium chloroacetate in hot water was first reported in 1880.[3]
The phenolate anion reacts via nucleophilic attack on the methylene carbon of the chloroacetic acid, forming an ether bond.
Phenoxyacetic acid is a white or clear crystalline compound at room temperature.[2] When impure, it can appear to be a light tan to brown. The compound has a solubility in water of 12 g/L and is highly soluble in organic solvents including ethanol, diethyl ether and benzene. Phenoxyacetic acid is a weak acid and weak base with a pKa of 3.7.[1][4]
Phenoxyacetic acid has found minor uses as a food additive and perfume component and is categorised as "generally recognised as safe" in these applications.[5][6]