Method and device for obtaining isobutenes from conjugated hydrocarbons

• Main Authors: LOHE BERND, BESSLING BERND, BROX WOLFGANG, KNAB JEAN WERNER
• Format: Patent
• Language: English
• Published: 26.03.2002
• Edition: 7
• Subjects: ACYCLIC OR CARBOCYCLIC COMPOUNDS; CHEMISTRY; METALLURGY; ORGANIC CHEMISTRY

A process for isolating isobutene from a hydrocarbon mixture bya) combining the C4-hydrocarbon mixture with a primary C3- or C4-alkanol;b) reacting the isobutene in the C4-hydrocarbon mixture with the primary C3- or C4-alkanol in the presence of a heterogeneous catalyst to give the corresponding tertiary ether of isobutene,c) separating the resultant reaction mixture into the relatively low-boiling, unetherified C4-hydrocarbons and the relatively higher-boiling tertiary ether of isobutene with the aid of a distillation column, where the C4-hydrocarbons are taken off at the top, and the tertiary ether of isobutene obtained at the bottom is transferred into a reactor,d) cleaving this ether into isobutene and the corresponding primary C3- or C4-alkanol,e) distilling this mixture from d) in a further distillation column, and taking off the isobutene as the top product,which comprises carrying out step a) in a zone (4C) containing reactive internals and containing the catalyst for carrying out step b) arranged in such a way that the zone (4C) is integrated into a distillation column (4), that a reactive distillation takes place in this zone (4C), and that the C3- or C4-alkanol is fed to the distillation column above the zone (4C) and the C4-hydrocarbon mixture is fed to the distillation column below the zone (4C).