:1-Hexyne
{{chembox
| ImageFile1 = Hex-1-yne.png
| ImageFile2 = 1-Hexyne-3D-vdW.png
| OtherNames = n-Butylacetylene
| PIN = Hex-1-yne
| Section1 = {{Chembox Identifiers
| ChemSpiderID_Ref = {{chemspidercite|correct|chemspider}}
| ChemSpiderID = 12209
| ChEBI = 176793
| EINECS = 211-736-9
| InChI = 1S/C6H10/c1-3-5-6-4-2/h1H,4-6H2,2H3
| InChIKey = CGHIBGNXEGJPQZ-UHFFFAOYSA-N
| SMILES1 = CCCCC#C
| CASNo= 693-02-7
| CASNo_Ref = {{cascite|correct|CAS}}
| UNII = 5FZF2F38F5
| PubChem=12732
}}
| Section2 = {{Chembox Properties
| C=6 | H=10
| Appearance= colorless liquid
(impure samples can appear yellowish)
| Density=0.72 g/cm3
| MeltingPtC = -132
| BoilingPtC = 71 to 72
| Solubility= 0.36 g/L
}}
| Section3 = {{Chembox Hazards
| MainHazards = Irritant, Flammable, Health Hazard
| ExternalSDS =
| NFPA-H =
| NFPA-F =
| NFPA-R =
| FlashPtC = -20
| AutoignitionPtC =
| GHSPictograms = {{GHS02}}{{GHS07}}{{GHS08}}
| GHSSignalWord = Danger
| HPhrases = {{H-phrases|225|304|315|319|335}}
| PPhrases = {{P-phrases|210|233|240|241|242|243|261|264|271|280|301+310|302+352|303+361+353|304+340|305+351+338|312|321|331|332+313|337+313|362|370+378|403+233|403+235|405|501}}
}}
| Watchedfields = changed
| verifiedrevid = 477218540
}}
1-Hexyne is a hydrocarbon consisting of a straight six-carbon chain having a terminal alkyne. Its molecular formula is {{chem2|HC2C4H9}}. A colorless liquid, it is one of three isomers of hexyne. It is used as a reagent in organic synthesis.
Synthesis and reactions
1-Hexyne can be prepared by the reaction of monosodium acetylide with butyl bromide:{{cite journal |author=Kenneth N. Campbell, Barbara K. Campbell|doi=10.15227/orgsyn.030.0015|title=n-Butylacetylene |journal=Organic Syntheses |year=1950 |volume=30 |page=15 }}
:{{chem2|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:
:{{chem2|HC2C4H9 + 2 BuLi -> LiC2CH(Li)C3H7 + 2 BuH}}
This reaction allows alkylation at the 3-position.{{cite journal |doi=10.15227/orgsyn.058.0001|author=A. J. Quillinan, F. Scheinmann|title=3-Alkyl-1-Alkynes Synthesis: 3-Ethyl-1-Hexyne |journal=Organic Syntheses |year=1978 |volume=58 |page=1 }}
Catechol borane adds to 1-hexyne to give the 1-hexenyl borane.
1-Hexyne reacts with diethyl fumarate to produce {{chem name|n-hexylsuccinic acid}}.{{Cite journal|last1=Hogsed|first1=M. J.|last2=Lindsey|first2=R. V.|date=1953-10-01|title=The Reaction of 1-Hexyne and Diethyl Fumarate|url=https://doi.org/10.1021/ja01115a517|journal=Journal of the American Chemical Society|volume=75|issue=19|pages=4846–4847|doi=10.1021/ja01115a517|issn=0002-7863}}