Methylacetylene

Methylacetylene (propyne) is an alkyne with the chemical formula CH₃C≡CH. It is a component of MAPP gas along with its isomer 1,2-propadiene (allene), which is commonly used in gas welding.

Additional recommended knowledge

Daily Sensitivity Test

Recognize and detect the effects of electrostatic charges on your balance

Don't let static charges disrupt your weighing accuracy

Use as a rocket fuel

Research by European space concerns into using light hydrocarbons with liquid oxygen as a relatively high performing propellant combination which would also be less toxic than the commonly used MMH/NTO (monomethylhydrazine/nitrogen tetroxide) systems, showed that propyne would be highly advantageous as a rocket fuel for craft intended for low Earth orbital operations. This conclusion was reached based upon a specific impulse expected to reach 370s if oxygen is used as oxidiser, a high density, and energy/volume ratio, and the moderate boiling point, which causes the chemical to present fewer problems in storage than for example a fuel that needs to be kept at extremely low temperatures. (See cryogenics.)

Use in organic chemistry

Propyne is a convenient three-carbon building block for synthesis. When propyne is condensed and treated with n-Butyllithium, solid propynyllithium is formed. This nucleophilic reagent can then be added to a carbonyl, producing a secondary alcohol. While purified propyne is expensive, in this reaction it can be replaced with MAPP gas to cheaply generate large amounts of the reagent.

References

• German Aerospace Center
• Nova Chemicals