1-Hexyne

1-Hexyne is a hydrocarbon consisting of a straight six-carbon chain having a terminal alkyne. Its molecular formula is HC₂C₄H₉. A colorless liquid, it is one of three isomers of hexyne.^[1] It is used as a reagent in organic synthesis.

1-Hexyne

Names
Preferred IUPAC name Hex-1-yne
Other names n-Butylacetylene
Identifiers
CAS Number	693-02-7 Y
3D model (JSmol)	Interactive image
ChEBI	CHEBI:176793
ChemSpider	12209 Y
ECHA InfoCard	100.010.671
EC Number	211-736-9
PubChem CID	12732
UNII	5FZF2F38F5
CompTox Dashboard (EPA)	DTXSID30870753
InChI InChI=1S/C6H10/c1-3-5-6-4-2/h1H,4-6H2,2H3 Key: CGHIBGNXEGJPQZ-UHFFFAOYSA-N
SMILES CCCCC#C
Properties
Chemical formula	C6H10
Molar mass	82.146 g·mol−1
Appearance	colorless liquid (impure samples can appear yellowish)
Density	0.72 g/cm3
Melting point	−132 °C (−206 °F; 141 K)
Boiling point	71 to 72 °C (160 to 162 °F; 344 to 345 K)
Solubility in water	0.36 g/L
Hazards
Occupational safety and health (OHS/OSH):
Main hazards	Irritant, Flammable, Health Hazard
GHS labelling:
Pictograms
Signal word	Danger
Hazard statements	H225, H304, H315, H319, H335
Precautionary statements	P210, P233, P240, P241, P242, P243, P261, P264, P271, P280, P301+P310, P302+P352, P303+P361+P353, P304+P340, P305+P351+P338, P312, P321, P331, P332+P313, P337+P313, P362, P370+P378, P403+P233, P403+P235, P405, P501
Flash point	−20 °C (−4 °F; 253 K)
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). Y verify (what is YN ?) Infobox references

Synthesis and reactions

1-Hexyne can be prepared by the reaction of monosodium acetylide with butyl bromide:^[1]

NaC₂H + BrC₄H₉ → HC₂C₄H₉ + NaBr

Its reactivity illustrates the behavior of terminal alkylacetylenes. The hexyl derivative is common test substrate because it is conveniently volatile. It undergoes deprotonation at C-3 and C-1 with butyl lithium:

HC₂C₄H₉ + 2 BuLi → LiC₂CH(Li)C₃H₇ + 2 BuH

This reaction allows alkylation at the 3-position.^[2]

Catechol borane adds to 1-hexyne to give the 1-hexenyl borane. ^[3]

1-Hexyne reacts with diethyl fumarate to produce n-hexylsuccinic acid.^[4]

See also

• 2-Hexyne
• 3-Hexyne