Process for the obtaining of isobutylene of high purity

摘要

A process for obtaining isobutylene in a purity greater than 99.5% from an initial feed of relatively pure isobutylene which further has minor quantities of tertiary butyl alcohol, water, polymers of isobutylene, and cis and trans-2-butenes in an economic manner while retaining good yields of the isobutylene by distilling the initial feed to separate a significant portion of the isobutylene with a purity equal to or greater than 99.5% with the remaining mixture containing tertiary butyl alcohol, water, polymers of isobutylene, cis and trans-2-butenes and isobutylene in an amount from 0 to 5% by weight; washing the latter mixture with water to obtain an aqueous phase of tertiary butyl alcohol and an organic phase containing the remainder of said mixture including the isobutylene not previously separated (and some tertiary butyl alcohol not dissolved in the wash water); and distilling the organic phase to separate the polymers of isobutylene from a mixture containing isobutylene and the cis and trans-2-butenes whereby the latter can be recovered by recycling for extraction; and distilling the aqueous phase to separate an azeotrope from the remainder of the water whereby the tertiary butyl alcohol in the azeotrope may be dehydrated to isobutylene.