Patent ID: 6852899

Claim:
A process for producing isobutylene and methanol comprising decomposing methyl-tert-butyl ether into isobutylene and methanol to obtain a mixture containing isobutylene and methanol, separating isobutylene and methanol therefrom, thereby individually recovering isobutylene and methanol, wherein the process comprising the following steps: a first step of subjecting methyl-tert-butyl ether to a decomposition reaction in the presence of a solid acid catalyst to obtain a reaction liquid containing isobutylene, methanol and, as by-products, a dialkyl ether and heavy components containing an isobutylene dimer and an isobutylene trimer; a second step of washing the reaction liquid obtained in the first step with water to separate the reaction liquid into an oil layer and an aqueous layer; a third step of subjecting the oil layer obtained in the second step to distillation using a distillation column to obtain a fraction containing isobutylene and the dialkyl ether from a top of the distillation column, a fraction containing methyl-tert-butyl ether and the heavy components from a bottom of the distillation column and a fraction containing methyl-tert-butyl ether from a side cut of the distillation column, and recycling the fraction obtained from the side cut to the first step; and a fourth step of subjecting the water layer obtained in the second step to distillation using a distillation column to obtain a fraction containing methanol from a top of the distillation column and a fraction containing water from a bottom of the distillation column.