Methoxyacetic acid

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Methoxyacetic acid
Methoxyessigsaure Strukturformel.svg
Names
IUPAC name
2-Methoxyacetic acid
Other names
2-Methoxyacetic acid
Methyl glycolic acid
Identifiers
ChEBI
ChemSpider
ECHA InfoCard 100.009.904 OOjs UI icon edit-ltr-progressive.svg
EC Number
  • 210-894-6
PubChem CID
UNII
Properties
C3H6O3
Molar mass 90.08 g/mol−1
AppearanceClear, 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).

Methoxyaceticacid is 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.

Contents

Due to its considerable reprotoxic potential, methoxyacetic acid has been adopted into the list of SVHC substances (substances of very high concern) [1] and is only registered as an intermediate product for industrial purposes under strictly controlled conditions.

For consumer applications, such as for the cleaning and decalcification of surfaces, the substance must be substituted by safe alternatives.

Production

With twice the molar amount of sodium methoxide in methanol, the conversion of monochloroacetic acid yields, after acidification of dry hydrogen chloride gas and vacuum distillation, methoxyacetic acid in amounts of about 90%. [2]

The route of synthesis is inefficient as it requires relatively expensive raw materials and large amounts of the intermediate product sodium chloride.

When methyl glycol is oxidized with concentrated nitric acid – even in the presence of vanadium(V) oxide – methoxyacetic acid is produced at a rate of about 85%. [3]

A disadvantage of the reaction using (excessively) hot nitric acid is the formation of nitrous gases, which – much like excessive nitric acid via the addition of urea and formaldehyde – must be avoided.

The most common procedure by industrial standards is the oxidation of methyl glycol with air or oxygen in the presence of platinum catalysts in a relatively high (10–30%) aqueous solution at a pH value of ≤ 7 and temperatures around 50 °C, producing amounts of up to 95% and space-time yields of 150 g · 1−1h−1. [4]

In both humans and animals, 2-methoxyacetic acid forms via the rapid oxidation of 2-methoxyethanol (methyl glycol) [5] via alcohol dehydrogenases.

Properties

Methoxyacetic acid is a clear, 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). [6]

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. [7]

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 in the body.

As a molecular component of multiple iodized aromatic compounds, methoxyacetic acid was once used in X-ray contrast agents. [8]

In laboratory tests, methoxyacetic acid inhibits the growth of tumor cells. [9]

Related Research Articles

<span class="mw-page-title-main">Acid</span> Chemical compound giving a proton or accepting an electron pair

An acid is a molecule or ion capable of either donating a proton (i.e. hydrogen ion, H+), known as a Brønsted–Lowry acid, or forming a covalent bond with an electron pair, known as a Lewis acid.

<span class="mw-page-title-main">Carboxylic acid</span> Organic compound containing a –C(=O)OH group

In organic chemistry, a carboxylic acid is an organic acid that contains a carboxyl group attached to an R-group. The general formula of a carboxylic acid is often written as R−COOH or R−CO2H, sometimes as R−C(O)OH with R referring to the alkyl, alkenyl, aryl, or other group. Carboxylic acids occur widely. Important examples include the amino acids and fatty acids. Deprotonation of a carboxylic acid gives a carboxylate anion.

<span class="mw-page-title-main">Ether</span> Organic compounds made of alkyl/aryl groups bound to oxygen (R–O–R)

In organic chemistry, ethers are a class of compounds that contain an ether group—an oxygen atom connected to two organyl groups. They have the general formula R−O−R′, where R and R′ represent organyl groups. Ethers can again be classified into two varieties: if the organyl groups are the same on both sides of the oxygen atom, then it is a simple or symmetrical ether, whereas if they are different, the ethers are called mixed or unsymmetrical ethers. A typical example of the first group is the solvent and anaesthetic diethyl ether, commonly referred to simply as "ether". Ethers are common in organic chemistry and even more prevalent in biochemistry, as they are common linkages in carbohydrates and lignin.

<span class="mw-page-title-main">Ester</span> Compound derived from an acid

In chemistry, an ester is a compound derived from an acid in which the hydrogen atom (H) of at least one acidic hydroxyl group of that acid is replaced by an organyl group. Analogues derived from oxygen replaced by other chalcogens belong to the ester category as well. According to some authors, organyl derivatives of acidic hydrogen of other acids are esters as well, but not according to the IUPAC.

Demethylation is the chemical process resulting in the removal of a methyl group (CH3) from a molecule. A common way of demethylation is the replacement of a methyl group by a hydrogen atom, resulting in a net loss of one carbon and two hydrogen atoms.

<span class="mw-page-title-main">Ethylene oxide</span> Cyclic compound (C2H4O)

Ethylene oxide is an organic compound with the formula C2H4O. It is a cyclic ether and the simplest epoxide: a three-membered ring consisting of one oxygen atom and two carbon atoms. Ethylene oxide is a colorless and flammable gas with a faintly sweet odor. Because it is a strained ring, ethylene oxide easily participates in a number of addition reactions that result in ring-opening. Ethylene oxide is isomeric with acetaldehyde and with vinyl alcohol. Ethylene oxide is industrially produced by oxidation of ethylene in the presence of a silver catalyst.

<span class="mw-page-title-main">Neutralization (chemistry)</span> Chemical reaction in which an acid and a base react quantitatively

In chemistry, neutralization or neutralisation is a chemical reaction in which acid and a base react with an equivalent quantity of each other. In a reaction in water, neutralization results in there being no excess of hydrogen or hydroxide ions present in the solution. The pH of the neutralized solution depends on the acid strength of the reactants.

<span class="mw-page-title-main">Anisole</span> Organic compound (CH₃OC₆H₅) also named methoxybenzene

Anisole, or methoxybenzene, is an organic compound with the formula CH3OC6H5. It is a colorless liquid with a smell reminiscent of anise seed, and in fact many of its derivatives are found in natural and artificial fragrances. The compound is mainly made synthetically and is a precursor to other synthetic compounds. Structurally, it is an ether with a methyl and phenyl group attached. Anisole is a standard reagent of both practical and pedagogical value.

<span class="mw-page-title-main">Glycolic acid</span> Chemical compound

Glycolic acid is a colorless, odorless and hygroscopic crystalline solid, highly soluble in water. It is used in various skin-care products. Glycolic acid is widespread in nature. A glycolate is a salt or ester of glycolic acid.

The National Pollutant Inventory (NPI) is a database of Australian pollution emissions managed by the Australian Commonwealth, State and Territory Governments. A condensed version of the information collected is available to the public via the Department’s website.

Glycol ethers are a class of chemical compounds consisting of alkyl ethers that are based on glycols such as ethylene glycol or propylene glycol. They are commonly used as solvents in paints and cleaners. They have good solvent properties while having higher boiling points than the lower-molecular-weight ethers and alcohols.

This is the list of extremely hazardous substances defined in Section 302 of the U.S. Emergency Planning and Community Right-to-Know Act. The list can be found as an appendix to 40 CFR 355. Updates as of 2006 can be seen on the Federal Register, 71 FR 47121.

<span class="mw-page-title-main">2-Methoxyethanol</span> Chemical compound

2-Methoxyethanol, or methyl cellosolve, is an organic compound with formula C
3
H
8
O
2
that is used mainly as a solvent. It is a clear, colorless liquid with an ether-like odor. It is in a class of solvents known as glycol ethers which are notable for their ability to dissolve a variety of different types of chemical compounds and for their miscibility with water and other solvents. It can be formed by the nucleophilic attack of methanol on protonated ethylene oxide followed by proton transfer:

<span class="mw-page-title-main">Mukaiyama Taxol total synthesis</span>

The Mukaiyama taxol total synthesis published by the group of Teruaki Mukaiyama of the Tokyo University of Science between 1997 and 1999 was the 6th successful taxol total synthesis. The total synthesis of Taxol is considered a hallmark in organic synthesis.

<span class="mw-page-title-main">Diglycolic acid</span> Chemical compound

Diglycolic acid is an aliphatic dicarboxylic acid, its acidity is between the one of acetic acid and oxalic acid. It is formed in the oxidation of diethylene glycol in the body and can lead to severe complications with fatal outcome.

<span class="mw-page-title-main">Acetic acid</span> Colorless and faint organic acid found in vinegar

Acetic acid, systematically named ethanoic acid, is an acidic, colourless liquid and organic compound with the chemical formula CH3COOH. Vinegar is at least 4% acetic acid by volume, making acetic acid the main component of vinegar apart from water. It has been used, as a component of vinegar, throughout history from at least the third century BC.

Commodity chemicals are a group of chemicals that are made on a very large scale to satisfy global markets. The average prices of commodity chemicals are regularly published in the chemical trade magazines and web sites such as Chemical Week and ICIS. There have been several studies of the scale and complexity of this market for example in the USA.

<span class="mw-page-title-main">Trinitroanisole</span> Chemical compound

Trinitroanisole is a chemical compound that exists as pale yellow crystals with a melting point of 68 °C. It is highly toxic. It is an explosive with a detonation velocity of 7200 meters per second. The compound's primary hazard is a blast of an instantaneous explosion, not flying projectiles or fragments.

<span class="mw-page-title-main">Propylene glycol methyl ether</span> Chemical compound

Propylene glycol methyl ether is an organic solvent with a wide variety of industrial and commercial uses. Similar to other glycol ethers, it is used as a carrier/solvent in printing/writing inks and paints/coatings. It also finds use as an industrial and commercial paint stripper. It is used as an antifreeze in diesel engines.

<span class="mw-page-title-main">Poly(propylene glycol) diglycidyl ether</span> Chemical compound

Poly(propylene glycol) diglycidyl ether (PPGDGE) is an organic chemical in the glycidyl ether family. There are a number of variations depending on the starting molecular weight of the polypropylene glycol. They have the formula (C3H6O)n.C6H10O3 and the IUPAC name is Poly[oxy(methyl-1,2-ethanediyl)],a-(2-oxiranylmethyl)-w-(2-oxiranylmethoxy)- A key use is as a modifier for epoxy resins as a reactive diluent and flexibilizer. It is REACH registered.

References

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  5. Mebus, C.A.; Welsch, F. (1989). "The possible role of one-carbon moieties in 2-methoxyethanol and 2-methoxyacetic acid-induced developmental toxicity". Toxicology and Applied Pharmacology. 99 (1): 98–109. doi:10.1016/0041-008X(89)90115-4. PMID   2471293.
  6. King, Edward J. (1960). "The Thermodynamics of Ionization of Amino Acids. V. The Ionization Constants of 3-Methoxy-DL-alanine (O-Methylserine) and Methoxyacetic Acid 1". Journal of the American Chemical Society. 82 (14): 3575–3578. doi:10.1021/ja01499a025. ISSN   0002-7863.
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  8. "Espacenet – search results". worldwide.espacenet.com. Retrieved 2023-12-05.
  9. Parajuli, Keshab R.; Zhang, Qiuyang; Liu, Sen; Patel, Neil K.; Lu, Hua; Zeng, Shelya X.; Wang, Guangdi; Zhang, Changde; You, Zongbing (2014). "Methoxyacetic acid suppresses prostate cancer cell growth by inducing growth arrest and apoptosis". American Journal of Clinical and Experimental Urology. 2 (4): 300–312. ISSN   2330-1910. PMC   4297326 . PMID   25606576.