Isobutyric acid

Last updated
Isobutyric acid [1]
Isobutyric-acid.svg
Isobutyric-acid-3D-balls-2.png
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 OOjs UI icon edit-ltr-progressive.svg
EC Number
  • 201-195-7
KEGG
PubChem CID
RTECS number
  • NQ4375000
UNII
UN number 2529
  • InChI=1S/C4H8O2/c1-3(2)4(5)6/h3H,1-2H3,(H,5,6) Yes check.svgY
    Key: KQNPFQTWMSNSAP-UHFFFAOYSA-N Yes check.svgY
  • 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:
GHS-pictogram-flamme.svg GHS-pictogram-acid.svg GHS-pictogram-skull.svg
Danger
H226, H302, H311, H314
P210, P280, P301+P312+P330, P303+P361+P353, P305+P351+P338+P310
NFPA 704 (fire diamond)
NFPA 704.svgHealth 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 carboxylic acid with structural formula (CH3)2CHCOOH. It is an isomer of butyric acid. It is classified as a short-chain fatty acid. Deprotonation or esterification gives derivatives called isobutyrates.

Contents

Isobutyric acid is a colorless liquid with a somewhat unpleasant odor. It is soluble in water and organic solvents. It is found naturally in carobs ( 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 hydrolysis of isobutyronitrile with alkalis and 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 esters are present naturally in a wide variety of foods and, at varying concentrations, can impart a range of flavors. [11] The compound's safety as a food additive was reviewed by an FAO and 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

Related Research Articles

<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">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.

<span class="mw-page-title-main">Fatty acid</span> Carboxylic acid

In chemistry, particularly in biochemistry, a fatty acid is a carboxylic acid with an aliphatic chain, which is either saturated or unsaturated. Most naturally occurring fatty acids have an unbranched chain of an even number of carbon atoms, from 4 to 28. Fatty acids are a major component of the lipids in some species such as microalgae but in some other organisms are not found in their standalone form, but instead exist as three main classes of esters: triglycerides, phospholipids, and cholesteryl esters. In any of these forms, fatty acids are both important dietary sources of fuel for animals and important structural components for cells.

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

Butyric acid, also known under the systematic name butanoic acid, is a straight-chain alkyl carboxylic acid with the chemical formula CH3CH2CH2CO2H. It is an oily, colorless liquid with an unpleasant odor. Isobutyric acid is an isomer. Salts and esters of butyric acid are known as butyrates or butanoates. The acid does not occur widely in nature, but its esters are widespread. It is a common industrial chemical and an important component in the mammalian gut.

<span class="mw-page-title-main">Propionic acid</span> Carboxylic acid with chemical formula CH3CH2CO2H

Propionic acid is a naturally occurring carboxylic acid with chemical formula CH
3CH
2CO
2H. It is a liquid with a pungent and unpleasant smell somewhat resembling body odor. The anion CH
3CH
2CO−
2 as well as the salts and esters of propionic acid are known as propionates or propanoates.

<span class="mw-page-title-main">Stearic acid</span> Eighteen-carbon straight-chain fatty acid

Stearic acid is a saturated fatty acid with an 18-carbon chain. The IUPAC name is octadecanoic acid. It is a soft waxy solid with the formula CH3(CH2)16CO2H. The triglyceride derived from three molecules of stearic acid is called stearin. Stearic acid is a prevalent fatty-acid in nature, found in many animal and vegetable fats, but is usually higher in animal fat than vegetable fat. It has a melting point of 69.4 °C and a pKa of 4.50.

<span class="mw-page-title-main">Thioester</span> Organosulfur compounds of the form R–SC(=O)–R’

In organic chemistry, thioesters are organosulfur compounds with the molecular structure R−C(=O)−S−R’. They are analogous to carboxylate esters with the sulfur in the thioester replacing oxygen in the carboxylate ester, as implied by the thio- prefix. They are the product of esterification of a carboxylic acid with a thiol. In biochemistry, the best-known thioesters are derivatives of coenzyme A, e.g., acetyl-CoA. The R and R' represent organyl groups, or H in the case of R.

<span class="mw-page-title-main">Malonic acid</span> Carboxylic acid with chemical formula CH2(COOH)2

Malonic acid (IUPAC systematic name: propanedioic acid) is a dicarboxylic acid with structure CH2(COOH)2. The ionized form of malonic acid, as well as its esters and salts, are known as malonates. For example, diethyl malonate is malonic acid's diethyl ester. The name originates from the Greek word μᾶλον (malon) meaning 'apple'.

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

Acrylic acid (IUPAC: propenoic acid) is an organic compound with the formula CH2=CHCOOH. It is the simplest unsaturated carboxylic acid, consisting of a vinyl group connected directly to a carboxylic acid terminus. This colorless liquid has a characteristic acrid or tart smell. It is miscible with water, alcohols, ethers, and chloroform. More than a million tons are produced annually.

<span class="mw-page-title-main">Valeric acid</span> Carboxylic acid – CH3(CH2)3COOH

Valeric acid or pentanoic acid is a straight-chain alkyl carboxylic acid with the chemical formula CH3(CH2)3COOH. Like other low-molecular-weight carboxylic acids, it has an unpleasant odor. It is found in the perennial flowering plant Valeriana officinalis, from which it gets its name. Its primary use is in the synthesis of its esters. Salts and esters of valeric acid are known as valerates or pentanoates. Volatile esters of valeric acid tend to have pleasant odors and are used in perfumes and cosmetics. Several, including ethyl valerate and pentyl valerate are used as food additives because of their fruity flavors.

Capric acid, also known as decanoic acid or decylic acid, is a saturated fatty acid, medium-chain fatty acid (MCFA), and carboxylic acid. Its formula is CH3(CH2)8COOH. Salts and esters of decanoic acid are called caprates or decanoates. The term capric acid is derived from the Latin "caper / capra" (goat) because the sweaty, unpleasant smell of the compound is reminiscent of goats.

<span class="mw-page-title-main">3-Methylbutanoic acid</span> Carboxylic acid with chemical formula (CH3)2CHCH2CO2H CH3CH2

3-Methylbutanoic acid, also known as β-methylbutyric acid or more commonly isovaleric acid, is a branched-chain alkyl carboxylic acid with the chemical formula (CH3)2CHCH2CO2H. It is classified as a short-chain fatty acid. Like other low-molecular-weight carboxylic acids, it has an unpleasant odor. The compound occurs naturally and can be found in many foods, such as cheese, soy milk, and apple juice.

Alpha hydroxy acids, or α-hydroxy acids, are a class of chemical compounds that consist of a carboxylic acid with a hydroxyl group substituent on the adjacent (alpha) carbon. Prominent examples are glycolic acid, lactic acid, mandelic acid and citric acid.

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

Methacrylic acid, abbreviated MAA, is an organic compound with the formula CH2=C(CH3)COOH. This colorless, viscous liquid is a carboxylic acid with an acrid unpleasant odor. It is soluble in warm water and miscible with most organic solvents. Methacrylic acid is produced industrially on a large scale as a precursor to its esters, especially methyl methacrylate (MMA), and to poly(methyl methacrylate) (PMMA).

Pelargonic acid, also called nonanoic acid, is an organic compound with structural formula CH3(CH2)7CO2H. It is a nine-carbon fatty acid. Nonanoic acid is a colorless oily liquid with an unpleasant, rancid odor. It is nearly insoluble in water, but very soluble in organic solvents. The esters and salts of pelargonic acid are called pelargonates or nonanoates.

Asparagusic acid is an organosulfur compound with the molecular formula C4H6O2S2 and systematically named 1,2-dithiolane-4-carboxylic acid. The molecule consists of a heterocyclic disulfide functional group (a 1,2-dithiolane) with a carboxylic acid side chain. It is found in asparagus and is believed to be the metabolic precursor to odorous sulfur compounds responsible for the distinctive smell of urine which has long been associated with eating asparagus.

<span class="mw-page-title-main">Hydroxybutyric acid</span> Index of chemical compounds with the same name

Hydroxybutyric acid is a group of four-carbon organic compounds that have both hydroxyl and carboxylic acid functional groups. They can be viewed as derivatives of butyric acid. The carboxylate anion and the esters of hydroxybutyric acids are known as hydroxybutyrates. β-hydroxybutyric acid is relevant to human health as it is a member of a class of products of fatty acid oxidation referred to as ketone bodies.

Decenoic acid is any mono-carboxylic acid with an unbranched chain of ten carbons connected by eight single bonds and one double bond; that is, a chemical compound with formula HO(O=)C–(CH
2)
k–CH=CH–(CH
2)
7-k–H, where k is between 0 and 7 inclusive.

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

Methyl isobutyrate is an organic compound with the formula CH3O2CCH(CH3)2. This colorless liquid, the methyl ester of isobutyric acid, is used as a solvent.

2-Methylbutanoic acid, also known as 2-methylbutyric acid is a branched-chain alkyl carboxylic acid with the chemical formula CH3CH2CH(CH3)CO2H, classified as a short-chain fatty acid. It exists in two enantiomeric forms, (R)- and (S)-2-methylbutanoic acid. (R)-2-methylbutanoic acid occurs naturally in cocoa beans and (S)-2-methylbutanoic occurs in many fruits such as apples and apricots, as well as in the scent of the orchid Luisia curtisii.

References

  1. ↑ Merck Index , 11th Edition, 5039
  2. ↑ "Front Matter". Nomenclature of Organic Chemistry : IUPAC Recommendations and Preferred Names 2013 (Blue Book). Cambridge: The Royal Society of Chemistry. 2014. p. 748. doi:10.1039/9781849733069-FP001. 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. 1 2 3 Chisholm, Hugh, ed. (1911). "Butyric Acid"  . Encyclopædia Britannica . Vol. 4 (11th ed.). Cambridge University Press. p. 892.
  7. 1 2 Riemenschneider, Wilhelm; Bolt, Hermann (2000). Esters, Organic. p. 10. doi:10.1002/14356007.a09_565. 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. ↑ Jenkins, P. R. (1985). "Carboxylic acids and derivatives". General and Synthetic Methods. Vol. 7. pp. 96–160. doi:10.1039/9781847556196-00096. 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. ↑ Amoore, J. E. (1967). "Specific Anosmia: A Clue to the Olfactory Code". Nature. 214 (5093): 1095–1098. Bibcode:1967Natur.214.1095A. doi:10.1038/2141095a0. PMID   4861233. S2CID   4222453.
  16. ↑ Lucas, Kerry A.; Filley, Jessica R.; Erb, Jeremy M.; Graybill, Eric R.; Hawes, John W. (2007). "Peroxisomal Metabolism of Propionic Acid and Isobutyric Acid in Plants". Journal of Biological Chemistry. 282 (34): 24980–24989. doi: 10.1074/jbc.m701028200 . PMID   17580301. S2CID   7143228.
  17. ↑ Williams, Megan N.; Jacobson, Amy (April 22, 2016). "Effect of Copulins on Rating of Female Attractiveness, Mate-Guarding, and Self-Perceived Sexual Desirability". Evolutionary Psychology. SAGE Publications. 14 (2): 147470491664332. doi: 10.1177/1474704916643328 . ISSN   1474-7049. PMC   10426864 .
  18. ↑ Matsumoto-Oda, Akiko; Oda, Ryo; Hayashi, Yukako; Murakami, Hiroshi; Maeda, Norihiko; Kumazaki, Kiyonori; Shimizu, Keiko; Matsuzawa, Tetsuro (2003). "Vaginal Fatty Acids Produced by Chimpanzees during Menstrual Cycles". Folia Primatologica. S. Karger AG. 74 (2): 75–79. doi:10.1159/000070000. ISSN   0015-5713. PMID   12778908.
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