tetrolic acid
{{chembox
| Name = Tetrolic acid
| ImageFile = Tetrolic Acid Structural Formula.svg
| ImageSize = 240px
| ImageAlt = Skeletal formula of tetrolic acid
| ImageFile2 = Tetrolic acid (2-butynoic acid) crystals.jpg
| ImageSize2 = 240px
| ImageAlt2 = Crystals of tetrolic acid
| PIN = But-2-ynoic acid
| OtherNames = 2-Butynoic acid
Butynoic acid
|Section1={{Chembox Identifiers
| ChemSpiderID_Ref = {{chemspidercite|correct|chemspider}}
| ChemSpiderID = 61810
| PubChem = 68535
| SMILES1 = CC#CC(=O)O
| CASNo = 590-93-2
| UNII_Ref = {{fdacite|correct|FDA}}
| UNII = W3AM9ANZ22
| InChI = 1S/C4H4O2/c1-2-3-4(5)6/h1H3,(H,5,6)
| InChIKey = LUEHNHVFDCZTGL-UHFFFAOYSA-N
}}
|Section2={{Chembox Properties
| Formula = {{chem2|CH3C\tCCO2H}}
| C=4|H=4|O=2
| MeltingPtC = 78
| MeltingPt_ref = {{RubberBible92nd|page=3.88}}
| BoilingPtC = 203
}}
}}
Tetrolic acid (2-butynoic acid) is a short-chain unsaturated carboxylic acid, described by the formula {{chem2|CH3\sC\tC\sCO2H}}. Salts and esters of tetrolic acid are known as tetrolates.
History
The first reported synthesis{{cite journal|last=Geuther|first=A.|author-link=Johann Georg Anton Geuther|title=Ethyldiacetic Acid and some of its Derivatives|journal=J. Chem. Soc.|year=1871|volume=24|pages=812–837|doi=10.1039/JS8712400808 }} of tetrolic acid is believed to be by German chemist Johann Georg Anton Geuther in 1871 as part of his work investigating the derivatives of ethyl acetoacetate.
Production
Tetrolic acid is manufacturedSmith, W. (1973) "Preparation of tetrolic acid" {{US Patent|3752848A}} on a commercial scale by treatment of propyne with a strong base (to form an acetylide), followed by carbon dioxide:
File:Synthesis of tetrolic acid.png
{{Clear left}}
Strong bases such as n-BuLi{{cite journal|doi = 10.1039/P19940002525|first1 = Basil|last1 = Hartzoulakis|first2 = David|last2 = Gani|title = Synthesis of (2S, 3R)- and (2S, 3S)-3-methylglutamic acid|journal = J. Chem. Soc., Perkin Trans. 1|pages = 2525–2531|volume = 1994|issue = 18|year = 1994}} and {{chem2|NaNH2}}{{OrgSynth|doi = 10.15227/orgsyn.042.0097|title = Tetrolic Acid (2-Butynoic Acid)|volume = 42|pages = 97|year = 1962|collvol = 5|collvolpages = 1043|prep = CV5P1043|first1 = J. C.|last1 = Kauer|first2 = M.|last2 = Brown}} can be used.
Properties
Tetrolic acid is highly soluble in polar solvents (water, ethanol) and can be recrystallized from non-polar solvents (such as heptane, hexane or toluene). The compound is a white crystalline solid which can exist in two polymorphous crystalline forms.{{cite journal|doi=10.1016/j.chemphys.2008.01.035|journal=Chemical Physics|year=2008|volume=345|issue=1|pages=49–64|title= Effects of "excessive" exciton interactions in polarized IR spectra of the hydrogen bond in 2-butynoic acid crystals: Proton transfer induced by dynamical co-operative interactions involving hydrogen bonds|last1= Flakus|first1= Henryk T.|last2= Hachuła|first2= Barbara|bibcode=2008CP....345...49F}}
The proton nuclear magnetic resonance (1H-NMR) spectrum in deuterated dimethyl sulfoxide shows a characteristic singlet peak at 1.99 ppm corresponding to the –{{chem2|CH3}} protons.
Tetrolic acid sublimes at temperatures above 20°C, and should ideally be stored in a sealed container in a refrigerator.{{cite journal|last1=Golden|first1=M.|date=2019|title=Thermal Stability of 2-Butynoic Acid (Tetrolic acid)|journal=Org. Process Res. Dev.|volume=23, (5)|issue=5|pages=1101–1104|doi=10.1021/acs.oprd.9b00106|s2cid=146028375 }}
Accelerated rate calorimetry (ARC) showed exothermic onset from 135 °C, precluding short-path distillation as a means of purification.
References
{{Commons category|Tetrolic acid}}
{{reflist}}