| Names | |
|---|---|
| Preferred IUPAC name Oct-4-yne | |
Other names
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| Identifiers | |
3D model (JSmol) | |
| ChemSpider | |
| ECHA InfoCard | 100.016.119 |
| EC Number |
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PubChem CID | |
| UNII | |
CompTox Dashboard (EPA) | |
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| Properties | |
| C8H14 | |
| Molar mass | 110.200 g·mol−1 |
| Appearance | colorless liquid |
| Density | 0.751 g/mL |
| Melting point | −103 °C (−153 °F; 170 K) |
| Boiling point | 131–132 °C (268–270 °F; 404–405 K) |
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). | |
4-Octyne, also known as dipropylethyne, is a type of alkyne with a triple bond at its fourth carbon (the '4-' indicates the location of the triple bond in the chain). Its formula is C8H14.
4-Octyne forms with 5-decyne, 3-hexyne, and 2-butyne a group of symmetric alkynes.
One method for synthesizing 4-octyne is the reaction between acetylene and two equivalents of 1-bromopropane. Acetylene is first deprotonated by a base to give an anion, which then undergoes nucleophilic substitution with the bromopropane. The resulting alkyne is again deprotonated and reacts similarly with a second molecule of bromopropane. This reaction can be carried out in liquid ammonia at −70 °C with sodium amide as the base. [1]
Another synthetic route is the elimination reaction of 4,5-dibromooctane, which can be done in similar conditions. [2]
4-octyne is a colorless liquid at room temperature. Its density at 25 °C and otherwise stable conditions is 0.751 g/mL. The boiling point is 131–132 °C. The average molar mass is 110.20 g/mol. [3]