Carboxylic acid with chemical formula (CH3)2CHCO2H
Isobutyric acid
[1]
Names
Preferred IUPAC name
2-Methylpropanoic acid
[2]
Other names
Isobutyric acid 2-Methylpropionic acid Isobutanoic acid
Identifiers
3DMet
ChEBI
ChEMBL
ChemSpider
DrugBank
ECHA InfoCard
100.001.087
EC Number
KEGG
RTECS number
UNII
UN number
2529
InChI=1S/C4H8O2/c1-3(2)4(5)6/h3H,1-2H3,(H,5,6)
Y Key: KQNPFQTWMSNSAP-UHFFFAOYSA-N
Y InChI=1/C4H8O2/c1-3(2)4(5)6/h3H,1-2H3,(H,5,6)
Key: KQNPFQTWMSNSAP-UHFFFAOYAB
Properties
C 4 H 8 O 2
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 (pK a )
4.86
[3]
-56.06x10−6 cm3 /mol
Hazards
[4]
[5]
GHS labelling :
Danger
H226 ,
H302 ,
H311 ,
H314
P210 ,
P280 ,
P301+P312+P330 ,
P303+P361+P353 ,
P305+P351+P338+P310
NFPA 704 (fire diamond)
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).
Chemical compound
Isobutyric acid , also known as 2-methylpropanoic acid or isobutanoic acid , is a
carboxylic acid with structural formula (
CH3 )2 CH
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
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]
CH3 CH=CH2 + CO + H2 O → (CH3 )2 CHCO2 H
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 )2 C(OH)-CO2 H.
[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
References
^
Merck Index , 11th Edition, 5039
^ "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 .
^ Bjerrum, J.; et al. (1958). Stability Constants . London: Chemical Society.
^ Sigma-Aldrich.
"Isobutyric acid" . Retrieved 2020-10-03 .
^
"NFPA Hazard Classification" . Retrieved 2020-10-03 .
^
a
b
c
Chisholm, Hugh , ed. (1911).
"Butyric Acid" .
Encyclopædia Britannica . Vol. 4 (11th ed.). Cambridge University Press. p. 892.
^
a
b Riemenschneider, Wilhelm; Bolt, Hermann (2000). Esters, Organic . p. 10.
doi :
10.1002/14356007.a09_565 .
ISBN
978-3527306732 .
^
"Biological pathways to produce methacrylate" . Archived from
the original on 2012-05-02. Retrieved 2011-10-07 .
^ I. Pierre and E. Puchot (1873). "New Studies on Valerianic Acid and its Preparation on a Large Scale". Ann. Chim. Phys . 28 : 366.
^ 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 .
^
"Isobutyric acid" . The Good Scents Company . Retrieved 2020-10-03 .
^ FAO/WHO Expert Committee on food additives (1998).
"Safety evaluation of certain food additives and contaminants" . Retrieved 2020-09-30 .
^
"Metabocard for isobutyric acid" . Human Metabolome Database . 2020-03-26. Retrieved 2020-09-30 .
^
FAO (1998).
"Specifications for flavourings: isobutyric acid" . Retrieved 2020-10-03 .
^ 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 .
^ 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 .
^ 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 . 14 (2). SAGE Publications: 147470491664332.
doi :
10.1177/1474704916643328 .
ISSN
1474-7049 .
PMC
10426864 .
^ 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 . 74 (2). S. Karger AG: 75–79.
doi :
10.1159/000070000 .
ISSN
0015-5713 .
PMID
12778908 .
Receptor (
ligands )
GlyR Tooltip Glycine receptor
Positive modulators:
Alcohols (e.g.,
brometone ,
chlorobutanol (chloretone) ,
ethanol (alcohol) ,
tert -butanol (2M2P) ,
tribromoethanol ,
trichloroethanol ,
trifluoroethanol )
Alkylbenzene sulfonate
Anandamide
Barbiturates (e.g.,
pentobarbital ,
sodium thiopental )
Chlormethiazole
D12-116
Dihydropyridines (e.g.,
nicardipine )
Etomidate
Ginseng constituents (e.g.,
ginsenosides (e.g.,
ginsenoside-Rf ))
Glutamic acid (glutamate)
Ivermectin
Ketamine
Neuroactive steroids (e.g.,
alfaxolone ,
pregnenolone (eltanolone) ,
pregnenolone acetate ,
minaxolone ,
ORG-20599 )
Nitrous oxide
Penicillin G
Propofol
Tamoxifen
Tetrahydrocannabinol
Triclofos
Tropeines (e.g.,
atropine ,
bemesetron ,
cocaine ,
LY-278584 ,
tropisetron ,
zatosetron )
Volatiles /
gases (e.g.,
chloral hydrate ,
chloroform ,
desflurane ,
diethyl ether (ether) ,
enflurane ,
halothane ,
isoflurane ,
methoxyflurane ,
sevoflurane ,
toluene ,
trichloroethane (methyl chloroform) ,
trichloroethylene )
Xenon
Zinc
Antagonists:
2-Aminostrychnine
2-Nitrostrychnine
4-Phenyl-4-formyl-N-methylpiperidine
αEMBTL
Bicuculline
Brucine
Cacotheline
Caffeine
Colchicine
Colubrine
Cyanotriphenylborate
Dendrobine
Diaboline
Endocannabinoids (e.g.,
2-AG ,
anandamide (AEA) )
Gaboxadol (THIP)
Gelsemine
iso-THAZ
Isobutyric acid
Isonipecotic acid
Isostrychnine
Laudanosine
N-Methylbicuculline
N-Methylstrychnine
N,N-Dimethylmuscimol
Nipecotic acid
Pitrazepin
Pseudostrychnine
Quinolines (e.g.,
4-hydroxyquinoline ,
4-hydroxyquinoline-3-carboxylic acid ,
5,7-CIQA ,
7-CIQ ,
7-TFQ ,
7-TFQA )
RU-5135
Sinomenine
Strychnine
Thiocolchicoside
Tutin
Negative modulators:
Amiloride
Benzodiazepines (e.g.,
bromazepam ,
clonazepam ,
diazepam ,
flunitrazepam ,
flurazepam )
Corymine
Cyanotriphenylborate
Daidzein
Dihydropyridines (e.g.,
nicardipine ,
nifedipine ,
nitrendipine )
Furosemide
Genistein
Ginkgo constituents (e.g.,
bilobalide ,
ginkgolides (e.g.,
ginkgolide A ,
ginkgolide B ,
ginkgolide C ,
ginkgolide J ,
ginkgolide M ))
Imipramine
NBQX
Neuroactive steroids (e.g.,
3α-androsterone sulfate ,
3β-androsterone sulfate ,
deoxycorticosterone ,
DHEA sulfate ,
pregnenolone sulfate ,
progesterone )
Opioids (e.g.,
codeine ,
dextromethorphan ,
dextrorphan ,
levomethadone ,
levorphanol ,
morphine ,
oripavine ,
pethidine ,
thebaine )
Picrotoxin (i.e.,
picrotin and
picrotoxinin )
PMBA
Riluzole
Tropeines (e.g.,
bemesetron ,
LY-278584 ,
tropisetron ,
zatosetron )
Verapamil
Zinc
NMDAR Tooltip N-Methyl-D-aspartate receptor
Transporter (
blockers )
GlyT1 Tooltip Glycine transporter 1
GlyT2 Tooltip Glycine transporter 2