Propyne

A terminal three-carbon alkyne whose hydration regiochemistry matters.

Formula
C3H4
Molar mass
40.06 g/mol
Also known as
prop-1-yne, Methylacetylene, 1-PROPYNE, Allylene, Methyl acetylene, Acetylene, methyl-

Overview

A terminal three-carbon alkyne whose hydration regiochemistry matters.

The methyl group and terminal hydrogen make its two triple-bond carbons inequivalent. Mercury-catalysed hydration leads through an enol to propanone, whereas an appropriate hydroboration–oxidation sequence gives propanal. The isolated carbonyl product is not the initially formed enol.

Identifiers

Formula
C3H4
Molar mass
40.06 g/mol
Also known as
prop-1-yne, Methylacetylene, 1-PROPYNE, Allylene, Methyl acetylene, Acetylene, methyl-
Chemical identifiers
SMILES
CC#C
InChI
InChI=1S/C3H4/c1-3-2/h1H,2H3
PubChem CID
6335

Properties

Melting Point
-102.7 °C
Boiling Point
-23.2 °C
Relative density (water = 1)
Relative density (water = 1): 0.70
Water solubility
In water, 3,640 mg/L at 25 °C

Related compounds

  • Alkynes

    Propyne is a specific member of the alkynes family.

References

  1. PubChem Compound Summary: Propyne (CID 6335)National Center for Biotechnology Information · PubChem

    Identity, molecular formula, molecular weight and aliases retrieved via PUG REST on 2026-09-08.

  2. OpenStax Organic Chemistry: Hydration of alkynesJohn McMurry · OpenStax · 2023

    Supports the qualitative structure and reactivity context; identity and numerical measurements retain their original references.

  3. Hazardous Substances Data Bank (HSDB): Propyne — melting pointHazardous Substances Data Bank (HSDB)

    Retrieved through PubChem PUG View on 2026-09-08. https://pubchem.ncbi.nlm.nih.gov/compound/6335#section=Melting-Point. Source value, complete property clause or compact miscibility statement retained; absent pressure, temperature or phase conditions are not inferred. Original reference: Lide, D.R., G.W.A. Milne (eds.). Handbook of Data on Organic Compounds. Volume I. 3rd ed. CRC Press, Inc. Boca Raton ,FL. 1994., p. V5: 4591

  4. Hazardous Substances Data Bank (HSDB): Propyne — boiling pointHazardous Substances Data Bank (HSDB)

    Retrieved through PubChem PUG View on 2026-09-08. https://pubchem.ncbi.nlm.nih.gov/compound/6335#section=Boiling-Point. Source value, complete property clause or compact miscibility statement retained; absent pressure, temperature or phase conditions are not inferred. Original reference: Lide, D.R., G.W.A. Milne (eds.). Handbook of Data on Organic Compounds. Volume I. 3rd ed. CRC Press, Inc. Boca Raton ,FL. 1994., p. V5: 4591

  5. ILO-WHO International Chemical Safety Cards (ICSCs): Propyne — densityILO-WHO International Chemical Safety Cards (ICSCs)

    Retrieved through PubChem PUG View on 2026-09-08. https://pubchem.ncbi.nlm.nih.gov/compound/6335#section=Density. Source value, complete property clause or compact miscibility statement retained; absent pressure, temperature or phase conditions are not inferred.

  6. Hazardous Substances Data Bank (HSDB): Propyne — solubilityHazardous Substances Data Bank (HSDB)

    Retrieved through PubChem PUG View on 2026-09-08. https://pubchem.ncbi.nlm.nih.gov/compound/6335#section=Solubility. Source value, complete property clause or compact miscibility statement retained; absent pressure, temperature or phase conditions are not inferred. Original reference: McAuliffe C; J Phys Chem 70: 1267-75 (1966)