A process for isolating purified 2-methoxypropene from a mixture which comprises 2,2-dimethoxypropane, 2-methoxypropene, methanol, acetone, and optionally other carbonyl group-containing compounds, which process involves subjecting the mixture to distillation, adding 2-aminoethanol and at least one base as assistants in the distillation, and isolating purified 2-methoxypropene.