3D model (
CompTox Dashboard (EPA)
|Molar mass||64.087 g·mol−1|
|Melting point||−21 – −19 °C (−6 – −2 °F; 252–254 K)|
|Boiling point||61–64 °C (142–147 °F; 334–337 K)|
Refractive index (nD)
|1.4283 (23 °C)|
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
Until the late 1960s, no successful synthesis of this seemingly simply preparable molecule was described. Although long-chain and more complex 1,4-diynes had been synthesized successfully before,
The successful isolation in small amounts succeeded by reacting propargyl bromide and to the respective
An improved synthesis method was published by Verkruijsse and Hasselaar in 1979. Copper chloride was substituted by copper(I) bromide as well as propargyl bromide by propargyl tosylate. At lower reaction temperatures and fewer by-products, the alkiyne was obtained after multistep extraction. According to the publication’s authors, this circumvented the problem that the solvent THF and the main compound share similar boiling points.
The compounds forms also during the exothermic reaction of
At room temperature the substance discolors from a colorless to a yellowish liquid, however, storage in diluted solutions at 0 °C is possible for multiple weeks.
While for 1,4-pentadiene the sp2-
Although microwave spectroscopy revealed besides a dipole moment of 0.516 D no significant distortions compared to an ideal tetrahedron, three different ionization energies are reported for the π-system.
1,4-pentadiyne is a common starting material for the synthesis of