# Tetrolic acid

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Tetrolic acid Names Preferred IUPAC name But-2-ynoic acid Other names 2-Butynoic acid Butynoic acid Identifiers CAS Number 590-93-2 3D model (JSmol) Interactive image ChemSpider 61810 Y ECHA InfoCard 100.008.815 PubChem CID 68535 UNII W3AM9ANZ22 Y CompTox Dashboard (EPA) DTXSID4060444 InChI InChI=1S/C4H4O2/c1-2-3-4(5)6/h1H3,(H,5,6) Key: LUEHNHVFDCZTGL-UHFFFAOYSA-N SMILES CC#CC(=O)O Properties Chemical formula CH3C≡CCO2H Molar mass 84.074 g·mol−1 Density 0.9641 g/cm3[1] Melting point 78 °C (172 °F; 351 K)[1] Boiling point 203 °C (397 °F; 476 K)[1] Related compounds Related compounds but-3-enoic acid Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). Infobox references

Chemical compound

**Tetrolic acid** (**2-butynoic acid**) is a short-chain unsaturated [carboxylic acid](/source/Carboxylic_acid), described by the formula CH3−C≡C−CO2H. [Salts](/source/Salts) and [esters](/source/Esters) of tetrolic acid are known as **tetrolates**.

## History

The first reported synthesis[2] of tetrolic acid is believed to be by German chemist [Johann Georg Anton Geuther](/source/Johann_Georg_Anton_Geuther) in 1871 as part of his work investigating the derivatives of [ethyl acetoacetate](/source/Ethyl_acetoacetate).

## Production

Tetrolic acid is manufactured[3] on a commercial scale by treatment of [propyne](/source/Propyne) with a strong base (to form an [acetylide](/source/Acetylide)), followed by [carbon dioxide](/source/Carbon_dioxide):

Scheme2

Strong bases such as [*n*-BuLi](/source/N-Butyllithium)[4] and [NaNH2](/source/Sodium_amide)[5] can be used.

## Properties

Tetrolic acid is highly soluble in polar solvents ([water](/source/Water), [ethanol](/source/Ethanol)) and can be recrystallized from non-polar solvents (such as [heptane](/source/Heptane), [hexane](/source/Hexane) or [toluene](/source/Toluene)). The compound is a white crystalline solid which can exist in two polymorphous crystalline forms.[6]

The [proton nuclear magnetic resonance](/source/Proton_nuclear_magnetic_resonance) (1H-NMR) spectrum in deuterated [dimethyl sulfoxide](/source/Dimethyl_sulfoxide) shows a characteristic singlet peak at 1.99 ppm corresponding to the –CH3 protons.

Tetrolic acid [sublimes](/source/Sublimation_(phase_transition)) at temperatures above 20 °C, so it is typically stored in a sealed container in a refrigerator.[7]

Accelerated rate [calorimetry](/source/Calorimetry) (ARC) showed exothermic onset from 135 °C, precluding short-path distillation as a means of purification.[7]

## References

Wikimedia Commons has media related to [Tetrolic acid](https://commons.wikimedia.org/wiki/Category:Tetrolic_acid).

1. ^ [***a***](#cite_ref-b92_1-0) [***b***](#cite_ref-b92_1-1) [***c***](#cite_ref-b92_1-2) Haynes, William M., ed. (2011). *[CRC Handbook of Chemistry and Physics](/source/CRC_Handbook_of_Chemistry_and_Physics)* (92nd ed.). Boca Raton, Florida: [CRC Press](/source/CRC_Press). p. 3.88. [ISBN](/source/ISBN_(identifier)) [1-4398-5511-0](https://en.wikipedia.org/wiki/Special:BookSources/1-4398-5511-0).

1. **[^](#cite_ref-2)** [Geuther, A.](/source/Johann_Georg_Anton_Geuther) (1871). "Ethyldiacetic Acid and some of its Derivatives". *[J. Chem. Soc.](/source/J._Chem._Soc.)* **24**: 812–837. [doi](/source/Doi_(identifier)):[10.1039/JS8712400808](https://doi.org/10.1039%2FJS8712400808).

1. **[^](#cite_ref-3)** Smith, W. (1973) "Preparation of tetrolic acid" [U.S. patent 3752848A](https://patents.google.com/patent/US3752848A)

1. **[^](#cite_ref-4)** Hartzoulakis, Basil; Gani, David (1994). "Synthesis of (2*S*, 3*R*)- and (2*S*, 3*S*)-3-methylglutamic acid". *[J. Chem. Soc., Perkin Trans. 1](/source/J._Chem._Soc.%2C_Perkin_Trans._1)*. **1994** (18): 2525–2531. [doi](/source/Doi_(identifier)):[10.1039/P19940002525](https://doi.org/10.1039%2FP19940002525).

1. **[^](#cite_ref-5)** Kauer, J. C.; Brown, M. (1962). ["Tetrolic Acid (2-Butynoic Acid)"](https://www.orgsyn.org/demo.aspx?prep=CV5P1043). *[Organic Syntheses](/source/Organic_Syntheses)*. **42**: 97. [doi](/source/Doi_(identifier)):[10.15227/orgsyn.042.0097](https://doi.org/10.15227%2Forgsyn.042.0097); *Collected Volumes*, vol. 5, p. 1043.

1. **[^](#cite_ref-6)** Flakus, Henryk T.; Hachuła, Barbara (2008). "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". *[Chemical Physics](/source/Chemical_Physics_(journal))*. **345** (1): 49–64. [Bibcode](/source/Bibcode_(identifier)):[2008CP....345...49F](https://ui.adsabs.harvard.edu/abs/2008CP....345...49F). [doi](/source/Doi_(identifier)):[10.1016/j.chemphys.2008.01.035](https://doi.org/10.1016%2Fj.chemphys.2008.01.035).

1. ^ [***a***](#cite_ref-stability_7-0) [***b***](#cite_ref-stability_7-1) Golden, M. (2019). "Thermal Stability of 2-Butynoic Acid (Tetrolic acid)". *Org. Process Res. Dev*. **23** (5): 1101–1104. [doi](/source/Doi_(identifier)):[10.1021/acs.oprd.9b00106](https://doi.org/10.1021%2Facs.oprd.9b00106). [S2CID](/source/S2CID_(identifier)) [146028375](https://api.semanticscholar.org/CorpusID:146028375).

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Adapted from the Wikipedia article [Tetrolic acid](https://en.wikipedia.org/wiki/Tetrolic_acid) by Wikipedia contributors ([contributor history](https://en.wikipedia.org/wiki/Tetrolic_acid?action=history)). Available under [Creative Commons Attribution-ShareAlike 4.0 International](https://creativecommons.org/licenses/by-sa/4.0/). Changes may have been made.