Propadiene

Production and equilibrium with methylacetylene

Propadiene exists in equilibrium with methylacetylene (propyne) and the mixture is sometimes called MAPD for methylacetylene-propadiene:

H₃C−C≡CH ⇌ H₂C=C=CH₂

for which K_eq = 0.22 at 270 °C or 0.1 at 5 °C.

MAPD is produced as a side product, often an undesirable one, of dehydrogenation of propane to produce propene, an important feedstock in the chemical industry. MAPD interferes with the catalytic polymerization of propene.