# Propiolic acid

> Mediated Wiki article. Canonical URL: https://mediated.wiki/source/Propiolic_acid
> Markdown URL: https://mediated.wiki/source/Propiolic_acid.md
> Source: https://en.wikipedia.org/wiki/Propiolic_acid
> Source revision: 1333880247
> License: Creative Commons Attribution-ShareAlike 4.0 International (https://creativecommons.org/licenses/by-sa/4.0/)

Propiolic acid Names Preferred IUPAC name Prop-2-ynoic acid[1] Other names Propiolic acid Acetylene carboxylic acid Propargylic acid Acetylene mono-carboxylic acid Identifiers CAS Number 471-25-0 Y 3D model (JSmol) Interactive image Beilstein Reference 878176 ChEBI CHEBI:33199 Y ChEMBL ChEMBL1213530 Y ChemSpider 9706 N ECHA InfoCard 100.006.763 EC Number 207-437-8 Gmelin Reference 81893 KEGG C00804 Y MeSH C011537 PubChem CID 10110 UNII P2QW39G9LZ Y CompTox Dashboard (EPA) DTXSID6060050 InChI InChI=1S/C3H2O2/c1-2-3(4)5/h1H,(H,4,5) N Key: UORVCLMRJXCDCP-UHFFFAOYSA-N N InChI=1/C3H2O2/c1-2-3(4)5/h1H,(H,4,5) Key: UORVCLMRJXCDCP-UHFFFAOYAX SMILES C#CC(=O)O Properties Chemical formula C3H2O2 Molar mass 70.047 g·mol−1 Density 1.1325 g/cm3 Melting point 9 °C (48 °F; 282 K) Boiling point 144 °C (291 °F; 417 K) (decomposes) Acidity (pKa) pka = 1.89 [2] Hazards GHS labelling:[3] Pictograms Signal word Danger Hazard statements H226, H301, H310, H315, H335 Precautionary statements P210, P233, P240, P241, P242, P243, P261, P262, P264, P270, P271, P280, P301+P310, P302+P350, P302+P352, P303+P361+P353, P304+P340, P310, P312, P321, P322, P330, P332+P313, P361, P362, P363, P370+P378, P403+P233, P403+P235, P405, P501 Safety data sheet (SDS) External MSDS Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). N verify (what is YN ?) Infobox references

Chemical compound

**Propiolic acid** is the organic compound with the formula HC2CO2H. It is the simplest [acetylenic](/source/Alkyne) [carboxylic acid](/source/Carboxylic_acid). It is a colourless liquid that crystallises to give silky crystals. Near its boiling point, it decomposes.

It is soluble in water and possesses an odor like that of [acetic acid](/source/Acetic_acid).[4][5]

## Preparation

It is prepared commercially by oxidizing [propargyl alcohol](/source/Propargyl_alcohol) at a lead electrode.[6] It can also be prepared by [decarboxylation](/source/Decarboxylation) of [acetylenedicarboxylic acid](/source/Acetylenedicarboxylic_acid).[*[citation needed](https://en.wikipedia.org/wiki/Wikipedia:Citation_needed)*]

## Reactions and applications

Exposure to [sunlight](/source/Sunlight) converts it into [trimesic acid](/source/Trimesic_acid) (benzene-1,3,5-tricarboxylic acid).[5] It undergoes [bromination](/source/Bromination) to give dibromoacrylic acid. With [hydrogen chloride](/source/Hydrogen_chloride) it forms chloroacrylic acid. Its [ethyl ester](/source/Ethyl_ester) condenses with [hydrazine](/source/Hydrazine) to form [pyrazolone](/source/Pyrazolone).[5]

It forms a characteristic explosive solid upon treatment to its [aqueous solution](/source/Aqueous_solution) with [ammoniacal](/source/Ammoniacal) [silver nitrate](/source/Silver_nitrate).[5] An amorphous explosive [precipitate](/source/Precipitate) forms with ammoniacal [cuprous chloride](/source/Cuprous_chloride).

## Propiolates

**Propiolates** are esters or salts of propiolic acid. Common examples include [methyl propiolate](/source/Methyl_propiolate) and [ethyl propiolate](/source/Ethyl_propiolate).

## See also

- [Propargyl](/source/Propargyl)

- [Propargyl alcohol](/source/Propargyl_alcohol)

## References

1. **[^](#cite_ref-iupac2013_1-0)** *Nomenclature of Organic Chemistry : IUPAC Recommendations and Preferred Names 2013 (Blue Book)*. Cambridge: [The Royal Society of Chemistry](/source/Royal_Society_of_Chemistry). 2014. p. 748. [doi](/source/Doi_(identifier)):[10.1039/9781849733069-FP001](https://doi.org/10.1039%2F9781849733069-FP001). [ISBN](/source/ISBN_(identifier)) [978-0-85404-182-4](https://en.wikipedia.org/wiki/Special:BookSources/978-0-85404-182-4).

1. **[^](#cite_ref-2)** ["Propiolic acid"](https://pubchem.ncbi.nlm.nih.gov/compound/propiolic_acid).

1. **[^](#cite_ref-3)** ["Propiolic acid"](https://pubchem.ncbi.nlm.nih.gov/compound/10110#section=Safety-and-Hazards). *pubchem.ncbi.nlm.nih.gov*. Retrieved 16 December 2021.

1. **[^](#cite_ref-4)** ed, Susan Budavari (1990). [*The Merck index an encyclopedia of chemicals, drugs, and biologicals*](https://archive.org/details/merckindexency00buda/page/7833) (11. ed., 2. print. ed.). Rahway, NJ: Merck. pp. [7833, 1911](https://archive.org/details/merckindexency00buda/page/7833). [ISBN](/source/ISBN_(identifier)) [9780911910285](https://en.wikipedia.org/wiki/Special:BookSources/9780911910285).

1. ^ [***a***](#cite_ref-EB1911_5-0) [***b***](#cite_ref-EB1911_5-1) [***c***](#cite_ref-EB1911_5-2) [***d***](#cite_ref-EB1911_5-3) [Chisholm, Hugh](/source/Hugh_Chisholm), ed. (1911). ["Propiolic Acid"](https://en.wikisource.org/wiki/1911_Encyclop%C3%A6dia_Britannica/Propiolic_Acid). *[Encyclopædia Britannica](/source/Encyclop%C3%A6dia_Britannica_Eleventh_Edition)*. Vol. 22 (11th ed.). Cambridge University Press. p. 449.

1. **[^](#cite_ref-6)** Wilhelm Riemenschneider (2002). "Carboxylic Acids, Aliphatic". *Ullmann's Encyclopedia of Industrial Chemistry*. Weinheim: Wiley-VCH. [doi](/source/Doi_(identifier)):[10.1002/14356007.a05_235](https://doi.org/10.1002%2F14356007.a05_235). [ISBN](/source/ISBN_(identifier)) [3527306730](https://en.wikipedia.org/wiki/Special:BookSources/3527306730).

---
Adapted from the Wikipedia article [Propiolic acid](https://en.wikipedia.org/wiki/Propiolic_acid) by Wikipedia contributors ([contributor history](https://en.wikipedia.org/wiki/Propiolic_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.