Patent ID: 6696612
Filing Date: 2004-02-24
Classification: C07C

Abstract:
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 respectively therefrom, thereby individually recovering isobutylene and methanol, the process comprising the following steps:a first step of subjecting methyl-tert-butyl ether to decomposition 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 a water 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 dialkylether from the top of the distillation column and a fraction containing methyl-tert-butyl ether and the heavy components from the bottom of the distillation column; 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 the top of the distillation column, a fraction containing water from the bottom of the distillation column and a fraction rich in tert-butanol from a side cut of the distillation column, and then recycling at least a part of the fraction obtained from the side cut to the first step.