Methoxyacetic acid
Chemical compound
From Wikipedia, the free encyclopedia
Methoxyacetic acid is the organic compound with the formula CH3OCH2CO2H. It can be viewed as a derivative of acetic acid in which a hydrogen atom of the methyl group is replaced by a methoxy group. As indicated by the synonym methyl glycolic acid, and as the simplest ether carboxylic acid, methoxyacetic acid can be understood as a methyl ether of glycolic acid.
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| Names | |
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| IUPAC name
2-Methoxyacetic acid | |
| Other names
2-Methoxyacetic acid Methyl glycolic acid | |
| Identifiers | |
3D model (JSmol) |
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| ChEBI | |
| ChEMBL | |
| ChemSpider | |
| ECHA InfoCard | 100.009.904 |
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PubChem CID |
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| UNII | |
CompTox Dashboard (EPA) |
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| Properties | |
| C3H6O3 | |
| Molar mass | 90.08 g/mol−1 |
| Appearance | Clear, colorless, viscous liquid with a pungent odor |
| Density | 1.1768 g/cm−3 |
| Melting point | 7–9 °C (45–48 °F; 280–282 K) |
| Boiling point | 202–204 °C (396–399 °F; 475–477 K) |
| Soluble in water, ethanol, and diethyl ether | |
| Vapor pressure | 1.8 mbar (20 °C) 4.8 mbar (50 °C) |
| Acidity (pKa) | 3.57 |
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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Production
In principle the compound can be prepared by reaction of sodium methoxide with monochloroacetic acid. The industrial route involves the oxidation of 2-methoxyethanol with air or oxygen in the presence of platinum catalysts.[1]
In both humans and animals, 2-methoxyacetic acid forms via the rapid oxidation of 2-methoxyethanol[2] by the action of alcohol dehydrogenases.
Properties
Methoxyacetic acid is a colorless, viscous, and corrosive liquid with a pungent odor which, at 7 °C, freezes to a mass similar to glacial acetic acid. Due to the low solvation energy of its methoxy group, methoxyacetic acid, with a pKa value of 3.57, is more acidic than acetic acid (pKa 4.757) and glycolic acid (pKa 3.832).[3]
Ultra-pure methoxyacetic acid (purity of 99.8%, freezing point of 8.4 °C) can be obtained via the multistep crystallization of the raw distillate, which is free of acid contaminations.[4]
Applications
Methoxyacetic acid is a precursor to two commercial fungicides, oxadixyl and mefenoxam.
Former applications
Due to its reprotoxic properties, earlier consumer and industrial applications of methoxyacetic acid as a disinfectant, biocide, or as a cleaner for the decalcification of surfaces are now obsolete. The same is true for substances such as the solvent 2-methoxyethanol or the PVC plasticizer bis(2-methoxyethyl) phthalate, which are metabolized to methoxyacetic acid.
Safety
Due to its considerable reprotoxic potential, methoxyacetic acid has been adopted into the list of SVHC substances (substances of very high concern)[5] and is only registered as an intermediate product for industrial purposes under strictly controlled conditions.
In laboratory tests, methoxyacetic acid inhibits the growth of tumor cells.[6]