Isobutyric acid

Source: Wikipedia, the free encyclopedia.
"Valerianic acid" redirects here. Not to be confused with Valerenic acid or Valeric acid.
Isobutyric acid[1]
Skeletal formula of isobutyric acid
Ball-and-stick model of the isobutyric acid molecule
Names
Preferred IUPAC name
2-Methylpropanoic acid[2]
Other names
Isobutyric acid
2-Methylpropionic acid
Isobutanoic acid
Identifiers
3D model (
JSmol
)
3DMet
ChEBI
ChEMBL
ChemSpider
DrugBank
ECHA InfoCard
 100.001.087 Edit this at Wikidata
EC Number
  • 201-195-7
IUPHAR/BPS
KEGG
RTECS number
  • NQ4375000
UNII
UN number 2529
  • InChI=1S/C4H8O2/c1-3(2)4(5)6/h3H,1-2H3,(H,5,6) checkY
    Key: KQNPFQTWMSNSAP-UHFFFAOYSA-N checkY
  • InChI=1/C4H8O2/c1-3(2)4(5)6/h3H,1-2H3,(H,5,6)
    Key: KQNPFQTWMSNSAP-UHFFFAOYAB
  • O=C(O)C(C)C
Properties
C4H8O2
Molar mass 88.11 g/mol
Density 0.9697 g/cm3 (0 °C)
Melting point −47 °C (−53 °F; 226 K)
Boiling point 155 °C (311 °F; 428 K)
Acidity (pKa) 4.86[3]
-56.06x10−6 cm3/mol
Hazards[4][5]
GHS labelling:
GHS02: FlammableGHS05: CorrosiveGHS06: Toxic
Danger
H226, H302, H311, H314
P210, P280, P301+P312+P330, P303+P361+P353, P305+P351+P338+P310
NFPA 704 (fire diamond)
NFPA 704 four-colored diamondHealth 3: Short exposure could cause serious temporary or residual injury. E.g. chlorine gasFlammability 2: Must be moderately heated or exposed to relatively high ambient temperature before ignition can occur. Flash point between 38 and 93 °C (100 and 200 °F). E.g. diesel fuelInstability 0: Normally stable, even under fire exposure conditions, and is not reactive with water. E.g. liquid nitrogenSpecial hazards (white): no code
3
2
0
Flash point 55 °C (131 °F; 328 K)
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).

Isobutyric acid, also known as 2-methylpropanoic acid or isobutanoic acid, is a

COOH. It is an isomer of butyric acid. It is classified as a short-chain fatty acid
. Deprotonation or esterification gives derivatives called isobutyrates.

Isobutyric acid is a colorless liquid with a somewhat unpleasant odor. It is soluble in water and organic solvents. It is found naturally in

Ceratonia siliqua), in vanilla, and in the root of Arnica dulcis, and as an ethyl ester in croton oil.[6]

Production

Isobutyric acid is manufactured by the oxidation of isobutyraldehyde, which is a byproduct of the hydroformylation of propylene.[7]

It can also be prepared by the high pressure

hydrocarboxylation (Koch reaction) from propylene:[7]

CH3CH=CH2 + CO + H2O → (CH3)2CHCO2H

Isobutyric acid can also be manufactured commercially using engineered bacteria with a sugar feedstock.[8]

Laboratory methods

Many routes are known including the

oxidation of isobutanol with potassium dichromate in the presence of sulfuric acid.[9] In the presence of proton donors, the action of sodium amalgam on methacrylic acid also gives isobutyric acid.[6]

Reactions

The acid reacts as a typical carboxylic acid: it can form amide, ester, anhydride, and chloride derivatives.[10] Its acid chloride is commonly used as the intermediate to obtain the others. When heated with a chromic acid solution it is oxidized to acetone. Alkaline potassium permanganate oxidizes it to α-hydroxyisobutyric acid, (CH3)2C(OH)-CO2H.[6]

Uses

Isobutyric acid and its volatile

WHO panel, who concluded that there were no concerns at the likely levels of intake.[12]

Biology

In humans, isobutyric acid is a minor product of the

gut microbiome and can also be produced by metabolism of its esters found in food.[13] It has a characteristic odor like rancid butter[14] (4-carbon organic compounds take the root, butyl, which is in turn from butyric which is in turn from the Latin word for butter and the Greek, βούτυρον) but anosmia for it has been reported in about 2.5% of people.[15]

The metabolism of isobutyric acid in plants has been studied.[16]

Isobutyric acid, along with several other short-chain fatty acids collectively known as "copulins," is found abundantly in human vaginal secretions. Levels of isobutyric acid fluctuate throughout the menstrual cycle, and it is hypothesized to act as an indicator of ovulatory status.[17] Similar cycles are observed in chimpanzees.[18]

See also

References

  1. ^ Merck Index, 11th Edition, 5039
  2. ISBN 978-0-85404-182-4
    .
  3. ^ Bjerrum, J.; et al. (1958). Stability Constants. London: Chemical Society.
  4. ^ Sigma-Aldrich. "Isobutyric acid". Retrieved 2020-10-03.
  5. ^ "NFPA Hazard Classification". Retrieved 2020-10-03.
  6. ^ a b c Chisholm, Hugh, ed. (1911). "Butyric Acid" . Encyclopædia Britannica. Vol. 4 (11th ed.). Cambridge University Press. p. 892.
  7. ^
    ISBN 978-3527306732. {{cite book}}: |journal= ignored (help
    )
  8. ^ "Biological pathways to produce methacrylate". Archived from the original on 2012-05-02. Retrieved 2011-10-07.
  9. ^ I. Pierre and E. Puchot (1873). "New Studies on Valerianic Acid and its Preparation on a Large Scale". Ann. Chim. Phys. 28: 366.
  10. ISBN 978-0-85186-884-4
    .
  11. ^ "Isobutyric acid". The Good Scents Company. Retrieved 2020-10-03.
  12. ^ FAO/WHO Expert Committee on food additives (1998). "Safety evaluation of certain food additives and contaminants". Retrieved 2020-09-30.
  13. ^ "Metabocard for isobutyric acid". Human Metabolome Database. 2020-03-26. Retrieved 2020-09-30.
  14. FAO (1998). "Specifications for flavourings: isobutyric acid"
    . Retrieved 2020-10-03.
  15. S2CID 4222453
    .
  16. S2CID 7143228
    .
  17. PMC 10426864
    .
  18. PMID 12778908
    .
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