This Demonstration simulates a reactive distillation column that produces iso-butene and methanol from the decomposition of methyl tert-butyl ether (MTBE). The reaction is MTBE ⇌ iso-butene + methanol. The column is fed with pure MTBE at stage 8. The reactive stages range from 6 to 11. The column has 16 stages, a partial reboiler, and a total condenser. For low Damköhler numbers (with molar hold-up equaling zero), methanol and iso-butene are not formed and the only species present in the column is MTBE. At high Damköhler numbers, we get almost pure methanol as a bottom and pure iso-butene as a distillate.