2-Hexin - 2-Hexin

Structural formula
Structural formula of 2-hexyne
Name 2-Hexin
other names
  • Hex-2-in
  • Methylpropylethin
  • Methylpropylacetylen
  • 1-Methyl-2-n-propylethin
  • 1-Methyl-2-n-propylacetylen
Sum formula C6H10
Brief description

colorless liquid [1]

External identifiers / databases
CAS number 764-35-2
EC number 212-117-6
ECHA-InfoCard 100.011.015
PubChem 33629
Wikidata Q209408
Molar mass 82.14 g · mol −1
Physical state



0,7315 g·cm−3 (20 °C)[2]

Melting point

−89,6 °C[2]

boiling point

84,5 °C[2]


almost insoluble in water, miscible with ethanol and diethyl ether , soluble in benzene , chloroform and petroleum ether [2]

Refractive index

1,4138 (20 °C)[2]

safety instructions
GHS hazard labeling [1]
02 - Highly / extremely flammable


H and P phrases H: 225
P: 210​‐​403+235 [1]
As far as possible and customary, SI units are used. Unless otherwise noted, the data given apply to standard conditions . Refractive index: Na-D line , 20 ° C

2-Hexyne is a chemical compound from the alkynes group and a constitutional isomer to 1-hexyne and 3-hexyne . It has the basic structure of hexane with a C≡C triple bond in the 2-position.

Extraction and presentation

2-hexyne can be prepared by a multistep synthesis of ethyne via the intermediate propyne by reaction with sodium amide and methyl bromide , or 1-bromopropane [3] as well as by alkylation of mono- and di -sodium acetylides are obtained. All ethynes are also formed during the pyrolysis of hard coal . [4]


2-hexyne is a colorless, flammable liquid that burns with a very sooty flame. It is insoluble in water, but easily soluble in ethanol and diethyl ether . [4] 2-Hexyne is a versatile synthetic building block.

Individual evidence

  1. a b c data sheet 2-hexyne (PDF) from Merck , accessed on March 6, 2011.
  2. a b c d e David R. Lide (Hrsg.): CRC Handbook of Chemistry and Physics. 90. Auflage. (Internet-Version: 2010), CRC Press/Taylor and Francis, Boca Raton, FL, Physical Constants of Organic Compounds, S. 3-284.
  3. ^ A. William Johnson: Essentials of Organic Chemistry , ISBN 978-0-76370432-2 , p. 242 ( limited preview in the Google book search).
  4. a b Wissenschaft-Online Lexika: Entry on "Hexine" in the Lexikon der Chemie. Retrieved March 9, 2011.