Propiolaldehyde

Propiolaldehyde is an organic compound with molecular formula HC₂CHO. It is the simplest chemical compound containing both alkyne and aldehyde functional groups. It is a colorless liquid with explosive properties.^[1]

Propiolaldehyde

Names
Preferred IUPAC name Prop-2-ynal
Other names Propynal; Propiolic aldehyde
Identifiers
CAS Number	624-67-9 Y
3D model (JSmol)	Interactive image
ChemSpider	11721
ECHA InfoCard	100.009.871
PubChem CID	12222
UNII	SJ8A65XF7N Y
CompTox Dashboard (EPA)	DTXSID3060790
SMILES C#CC=O
Properties
Chemical formula	C3H2O
Molar mass	54.048 g·mol−1
Appearance	colorless liquid
Density	0.9152 g/cm3
Boiling point	54–57 °C (129–135 °F; 327–330 K)
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). Infobox references

Reactions

The compound exhibits reactions expected for an electrophilic alkynyl aldehyde. It is a dienophile and a good Michael acceptor. Grignard reagents add to the carbonyl center.^[1] Its explosive properties are attributed to the exothermicity of its polymerization.^[1]

Preparation

Its acetal can be prepared from acrolein.^[2]

Occurrence in interstellar medium

Propynal has been observed in the interstellar medium. It is hypothesized to be formed from a carbon monoxide-acetylene complex.^[3] Another possible pathway is through the reaction of propynylidyne (C₃H) with water.^[4]

Hazards

The compound is explosive, possibly because it tends to polymerize.^[1]

See also

• Acrolein
• Propiolic acid