2-Pentyne

2-Pentyne, an organic compound with the formula CH₃CH₂C≡CCH₃ and is an internal alkyne. It is an isomer of 1-pentyne, a terminal alkyne.

1-Pentyne

2-Pentyne

Skeletal formula of 2-pentyne
Ball-and-stick model of 2-pentyne
Names
Preferred IUPAC name Pent-2-yne
Other names Ethylmethylacetylene, 1-Ethyl-2-methylacetylene propyl acetylene
Identifiers
CAS Number	627-21-4 Y
3D model (JSmol)	Interactive image Interactive image
ChemSpider	11807 Y
ECHA InfoCard	100.009.991
PubChem CID	12310
UNII	57NG6HKI9D Y
CompTox Dashboard (EPA)	DTXSID80211758
InChI InChI=1S/C5H8/c1-3-5-4-2/h3H2,1-2H3 Y Key: NKTDTMONXHODTI-UHFFFAOYSA-N Y InChI=1/C5H8/c1-3-5-4-2/h3H2,1-2H3
SMILES CC#CCC C(#CCC)C
Properties
Chemical formula	C5H8
Molar mass	68.12
Density	0.71 g/mL
Melting point	−109 °C (−164 °F; 164 K)
Boiling point	56 to 57 °C
Hazards
Occupational safety and health (OHS/OSH):
Main hazards	Flammable Liquid
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

Synthesis

2-Pentyne can be synthesized by the rearrangement 1-pentyne in a solution of ethanolic potassium hydroxide or NaNH2/NH3.^[1]