Abstract: In the multistage distillation of a methyl tertiary butyl ether reaction product comprising methyl tertiary butyl ether, tertiary butyl alcohol, methanol, isobutylene and water, the methyl tertiary butyl ether reaction product is separated in a primary methyl tertiary butyl ether distillation column into a lower boiling methyl tertiary butyl ether fraction and a higher boiling aqueous tertiary butyl alcohol fraction; the lower boiling aqueous tertiary butyl alcohol fraction is separated in a tertiary butyl alcohol distillation column into a vaporized overhead tertiary butyl alcohol fraction and a higher boiling water fraction; cooling water is charged to the reflux condenser for the tertiary butyl alcohol distillation column to liquify the vaporized, overhead tertiary butyl alcohol fraction and to convert the cooling water to wet steam, and the wet steam is independently charged to the reboiler for the primary methyl tertiary butyl ether distillation zone to supply the heat necessary for the distillation to b

Abstract: An impure methyl tertiary butyl ether product contaminated with isobutylene, methanol and water is purified by continuous counter-current contact with water and isobutylene in a counter-current contact extraction tower to provide an overhead extract comprising isobutylene, methyl tertiary butyl ether and water and a raffinate comprising methanol, water and a minor amount of methyl tertiary butyl ether, the overhead raffinate being separated in a methyl tertiary butyl ether purification distillation zone into a lighter distillation fraction comprising isobutylene and water and a heavier distillation fraction consisting essentially of methyl tertiary butyl ether, the lighter distillation fraction being decanted to remove water and to provide a distillate isobutylene fraction that is charged to a surge drum from which isobutylene is returned to the contact tower.