Propiolic acid is the organic compound with the formula HC2CO2H. It is the simplest acetylenic carboxylic acid. It is a colourless liquid that crystallises to give silky crystals. Near its boiling point, it decomposes.
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| Names | |
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| Preferred IUPAC name
Prop-2-ynoic acid[1] | |
| Other names
Propiolic acid
Acetylene carboxylic acid Propargylic acid Acetylene mono-carboxylic acid | |
| Identifiers | |
3D model (JSmol)
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| 878176 | |
| ChEBI | |
| ChEMBL | |
| ChemSpider | |
| ECHA InfoCard | 100.006.763 |
| EC Number |
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| 81893 | |
| KEGG | |
| MeSH | C011537 |
PubChem CID
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| UNII | |
CompTox Dashboard (EPA)
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| Properties | |
| 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] | |
  
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| Danger | |
| H226, H301, H310, H315, H335 | |
| 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).
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It is soluble in water and possesses an odor like that of acetic acid.[4][5]
Preparation
editIt is prepared commercially by oxidizing propargyl alcohol at a lead electrode.[6] It can also be prepared by decarboxylation of acetylenedicarboxylic acid.
Reactions and applications
editExposure to sunlight converts it into trimesic acid (benzene-1,3,5-tricarboxylic acid).[5] It undergoes bromination to give dibromoacrylic acid. With hydrogen chloride it forms chloroacrylic acid. Its ethyl ester condenses with hydrazine to form pyrazolone.[5]
It forms a characteristic explosive solid upon treatment to its aqueous solution with ammoniacal silver nitrate.[5] An amorphous explosive precipitate forms with ammoniacal cuprous chloride.
Propiolates
editPropiolates are esters or salts of propiolic acid. Common examples include methyl propiolate and ethyl propiolate.
See also
editReferences
edit- ^ 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.
- ^ "Propiolic acid".
- ^ "Propiolic acid". pubchem.ncbi.nlm.nih.gov. Retrieved 16 December 2021.
- ^ ed, Susan Budavari (1990). The Merck index an encyclopedia of chemicals, drugs, and biologicals (11. ed., 2. print. ed.). Rahway, NJ: Merck. pp. 7833, 1911. ISBN 9780911910285.
- ^ a b c d Chisholm, Hugh, ed. (1911). . Encyclopædia Britannica. Vol. 22 (11th ed.). Cambridge University Press. p. 449.
- ^ Wilhelm Riemenschneider (2002). "Carboxylic Acids, Aliphatic". Ullmann's Encyclopedia of Industrial Chemistry. Weinheim: Wiley-VCH. doi:10.1002/14356007.a05_235. ISBN 3527306730.