Acetate

Source: Wikipedia, the free encyclopedia.
For other uses, see Acetate (disambiguation).
Acetate
Ball-and-stick model of the acetate anion
Names
IUPAC name
Acetate
Systematic IUPAC name
Ethanoate
Identifiers
3D model (
JSmol
)
ChemSpider
UNII
  • InChI=1S/C2H4O2/c1-2(3)4/h1H3,(H,3,4)/p-1
    Key: QTBSBXVTEAMEQO-UHFFFAOYSA-M
  • InChI=1/C2H4O2/c1-2(3)4/h1H3,(H,3,4)/p-1
    Key: QTBSBXVTEAMEQO-REWHXWOFAL
  • CC(=O)[O-]
Properties
C
2H
3O−
2
Conjugate acid
 Acetic acid
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).

An acetate is a

cation) are also commonly called "acetates" (hence, acetate of lead, acetate of aluminium, etc.). The simplest of these is hydrogen acetate (called acetic acid) with corresponding salts, esters, and the polyatomic anion
CH
3CO−
2, or CH
3COO−
.

Most of the approximately 5 million tonnes of acetic acid produced annually in industry are used in the production of acetates, which usually take the form of

polymers. In nature, acetate is the most common building block for biosynthesis
.

Nomenclature and common formula

When part of a

pseudoelement symbol "Ac" is also sometimes encountered in chemical formulas as indicating the entire acetate ion (CH
3CO−
2).[citation needed] It is not to be confused with the symbol of actinium, the first element of the actinide series; context guides disambiguation. For example, the formula for sodium acetate might be abbreviated as "NaOAc", rather than "NaC2H3O2". Care should also be taken to avoid confusion with peracetic acid
when using the OAc abbreviation; for clarity and to avoid errors when translated, HOAc should be avoided in literature mentioning both compounds.

Although its systematic name is ethanoate (/ɪˈθænoʊ.eɪt/), the common acetate remains the preferred IUPAC name.[4]

Salts

acetate anion

The acetate

conjugate base of acetic acid. Above a pH of 5.5, acetic acid converts to acetate:[1]

CH3COOH ⇌ CH3COO− + H+

Many acetate salts are ionic, indicated by their tendency to dissolve well in water. A commonly encountered acetate in the home is sodium acetate, a white solid that can be prepared by combining vinegar and sodium bicarbonate ("bicarbonate of soda"):

CH3COOH + NaHCO3 → CH3COO−Na+ + H2O + CO2

Transition metals can be complexed by acetate. Examples of acetate complexes include chromium(II) acetate and basic zinc acetate.

Commercially important acetate salts are aluminium acetate, used in dyeing, ammonium acetate, a precursor to acetamide, and potassium acetate, used as a diuretic. All three salts are colourless and highly soluble in water.[5]

Esters

acetate ester

Acetate esters have the general formula CH3CO2R, where R is an organyl group. The esters are the dominant forms of acetate in the marketplace. Unlike the acetate salts, acetate esters are often liquids, lipophilic, and sometimes volatile. They are popular because they have inoffensive, often sweet odors, they are inexpensive, and they are usually of low toxicity.

Almost half of acetic acid production is consumed in the production of vinyl acetate, precursor to polyvinyl alcohol, which is a component of many paints. The second largest use of acetic acid is consumed in the production of cellulose acetate. In fact, "acetate" is jargon for cellulose acetate, which is used in the production of fibres or diverse products, e.g. the acetate discs used in audio record production. Cellulose acetate can be found in many household products. Many industrial solvents are acetates, including methyl acetate, ethyl acetate, isopropyl acetate, ethylhexyl acetate. Butyl acetate is a fragrance used in food products.[5]

Acetate in biology

Acetate is a common anion in biology. It is mainly utilized by organisms in the form of acetyl coenzyme A.[6]

nociceptive behavior.[7][8]

Acetate has known

immunomodulatory properties and can affect the innate immune response to pathogenic bacteria such as the respiratory pathogen Haemophilus influenzae.[9]

Fermentation acetyl CoA to acetate

Pyruvate is converted into acetyl-coenzyme A (acetyl-CoA) by the enzyme pyruvate dehydrogenase. This acetyl-CoA is then converted into acetate in E. coli, whilst producing ATP by substrate-level phosphorylation. Acetate formation requires two enzymes: phosphate acetyltransferase and acetate kinase.[10]

The mixed acid fermentation pathway is characteristic of the family Enterobacteriaceae, which includes E. coli

      acetyl-CoA + phosphate → acetyl-phosphate + CoA

      acetyl-phosphate + ADP → acetate + ATP

Fermentation of acetate

Acetic acid can also undergo a

dismutation reaction to produce methane and carbon dioxide:[11][12]

CH3COO− + H+ → CH4 + CO2   ΔG° = −36 kJ/mol

This

methyl group (e− acceptor
) of acetic acid to respectively produce CO2 and methane gas.

Structures

See also

References

  1. ^
    ISBN 0-669-04529-2
    .
  2. ISBN 0-85404-438-8. p. 63. Electronic version.
  3. S2CID 55102299
    .
  4. ^ R-9.1 Trivial and semisystematic names retained for naming organic compounds Archived 2014-02-08 at the Wayback Machine, A Guide to IUPAC Nomenclature of Organic Compounds, IUPAC Commission on Nomenclature of Organic Chemistry
  5. ^
    doi:10.1002/14356007.a01_045
  6. ISBN 1-57259-153-6
    .
  7. PMID 21209842
    .
  8. ^ 'Is coffee the real cure for a hangover?' by Bob Holmes, New Scientist, Jan. 15 2011, p. 17.
  9. PMID 35085362
    .
  10. PMID 21097882
    .
  11. PMID 1512186
    .
  12. ^ Vogels, G. D.; Keltjens, J. T.; Van Der Drift, C. (1988). "Biochemistry of methane production". In Zehnder A.J.B. (ed.). Biology of anaerobic microorganisms. New York: Wiley. pp. 707–770.

External links

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