4 Octyne

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. 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.

4-Octyne forms with 5-decyne, 3-hexyne, and 2-butyne a group of symmetric alkynes.