Carboxylic acid with chemical formula (CH3)2CHCO2H
Isobutyric acid[ 1] Names Preferred IUPAC name 2-Methylpropanoic acid
[ 2] Other namesIsobutyric acid
Identifiers 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] −56.06×10−6 cm3 /mol Hazards[ 4] [ 5] GHS labellingDanger H226, H302, H311, H314 P210, P280, P301+P312+P330, P303+P361+P353, P305+P351+P338+P310 NFPA 704 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 as2-methylpropanoic acid orisobutanoic acid , is acarboxylic acid with structural formula (CH3 )2 CHCOOH . It is anisomer ofbutyric acid . It is classified as ashort-chain fatty acid . Deprotonation or esterification gives derivatives calledisobutyrates .
Isobutyric acid is a colorless liquid with a somewhat unpleasant odor. It is soluble in water and organic solvents. It is found naturally incarobs (Ceratonia siliqua vanilla , and in the root ofArnica dulcisester incroton oil .[ 6]
Isobutyric acid is manufactured by the oxidation ofisobutyraldehyde , which is a byproduct of thehydroformylation ofpropylene .[ 7]
It can also be prepared by the high pressurehydrocarboxylation (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]
Many routes are known including thehydrolysis ofisobutyronitrile withalkalis and theoxidation ofisobutanol withpotassium dichromate in the presence ofsulfuric acid .[ 9] sodium amalgam onmethacrylic acid also gives isobutyric acid.[ 6]
The acid reacts as a typical carboxylic acid: it can formamide ,ester ,anhydride , andchloride derivatives.[ 10] chromic acid solution it is oxidized toacetone . Alkalinepotassium permanganate oxidizes it toα -hydroxyisobutyric acid, (CH3 )2 C(OH)-CO2 H.[ 6]
Isobutyric acid and its volatileesters are present naturally in a wide variety of foods and, at varying concentrations, can impart a range of flavors.[ 11] FAO andWHO panel, who concluded that there were no concerns at the likely levels of intake.[ 12]
In humans, isobutyric acid is a minor product of thegut microbiome and can also be produced by metabolism of its esters found in food.[ 13] [ 14] anosmia for it has been reported in about 2.5% of people.[ 15]
Themetabolism 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 themenstrual cycle , and it is hypothesized to act as an indicator ofovulatory status.[ 17] [ 18]
^ Merck Index 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" . Retrieved2020-10-03 . ^ "NFPA Hazard Classification" . Retrieved2020-10-03 .^a b c Chisholm, Hugh , ed. (1911)."Butyric Acid" Encyclopædia Britannica ^a b Riemenschneider, Wilhelm; Bolt, Hermann (2000). "Esters, Organic".Ullmann's Encyclopedia of Industrial Chemistry . p. 10.doi :10.1002/14356007.a09_565 .ISBN 978-3527306732 ^ "Biological pathways to produce methacrylate" . Archived fromthe original on 2012-05-02. Retrieved2011-10-07 .^ 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 . Retrieved2020-10-03 .^ FAO/WHO Expert Committee on food additives (1998)."Safety evaluation of certain food additives and contaminants" . Retrieved2020-09-30 . ^ "Metabocard for isobutyric acid" .Human Metabolome Database . 2020-03-26. Retrieved2020-09-30 .^ FAO (1998)."Specifications for flavourings: isobutyric acid" . Retrieved2020-10-03 .^ 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 THAZ 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 andpicrotoxinin )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
