Phenylpropiolic acid, C6H5CCCO2H, formed by the action of alcoholic potash on cinnamic acid dibromide, C6H5CHBrCHBrCO2H, crystallizes in long needles or prisms which melt at 136–137 °C. When heated with water to 120 °C, it yields phenylacetylene (C6H5CCH). Chromic acid oxidizes it to benzoic acid; zinc and acetic acid reduce it to cinnamic acid, C6H5CH=CHCO2H, whilst sodium amalgam reduces it to hydrocinnamic acid, C6H5CH2CH2CO2H. Ortho-nitrophenylpropiolic acid, NO2C6H4CCCO2H, prepared by the action of alcoholic potash on ortho-nitrocinnamic acid dibromide, crystallizes in needles which decompose when heated to 155–156 °C. It is readily converted into indigo.[1]

Phenylpropiolic acid
Skeletal formula of phenylpropiolic acid
Ball-and-stick model
Names
Preferred IUPAC name
3-Phenylprop-2-ynoic acid
Other names
Phenylpropynoic acid; Phenylpropiolic acid
Identifiers
3D model (JSmol)
ChEBI
ChemSpider
ECHA InfoCard 100.010.260 Edit this at Wikidata
UNII
  • InChI=1S/C9H6O2/c10-9(11)7-6-8-4-2-1-3-5-8/h1-5H,(H,10,11) checkY
    Key: XNERWVPQCYSMLC-UHFFFAOYSA-N checkY
  • InChI=1/C9H6O2/c10-9(11)7-6-8-4-2-1-3-5-8/h1-5H,(H,10,11)
    Key: XNERWVPQCYSMLC-UHFFFAOYAX
  • O=C(C#Cc1ccccc1)O
Properties
C9H6O2
Molar mass 146.14 g/mol
Melting point 135 to 137 °C (275 to 279 °F; 408 to 410 K)
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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References edit

  1. ^   This article incorporates text from a publication now in the public domainChisholm, Hugh, ed. (1911). "Propiolic Acid". Encyclopædia Britannica. Vol. 22 (11th ed.). Cambridge University Press. p. 449.