US 12,448,342 B2
Process for obtaining isobutene from a C4-hydrocarbon mixture
Suman Thotla, Ludwigshafen am Rhein (DE); Hans-Guenter Wagner, Ludwigshafen am Rhein (DE); Randolf Hugo, Ludwigshafen am Rhein (DE); Gerrit Waters, Ludwigshafen am Rhein (DE); Michael Huebner, Freeport, TX (US); Markus Neudert, Ludwigshafen am Rhein (DE); and Thomas Roussiere, Ludwigshafen am Rhein (DE)
Assigned to BASF SE, Ludwigshafen am Rhein (DE)
Appl. No. 18/280,686
Filed by BASF SE, Ludwigshafen am Rhein (DE)
PCT Filed Mar. 1, 2022, PCT No. PCT/EP2022/055187
§ 371(c)(1), (2) Date Sep. 7, 2023,
PCT Pub. No. WO2022/189219, PCT Pub. Date Sep. 15, 2022.
Claims priority of application No. 21161220 (EP), filed on Mar. 8, 2021.
Prior Publication US 2024/0150264 A1, May 9, 2024
This patent is subject to a terminal disclaimer.
Int. Cl. C07C 7/05 (2006.01); C07C 1/22 (2006.01)
CPC C07C 7/05 (2013.01) [C07C 1/22 (2013.01)] 14 Claims
OG exemplary drawing
 
1. A process for obtaining isobutene from an isobutene containing C4-hydrocarbon mixture in a plant comprising an etherification unit, a first distillation unit, an ether cleavage unit and a second distillation unit, the process comprising:
(a) contacting the C4-hydrocarbon mixture with a primary alcohol and reacting the C4-hydrocarbon mixture with the primary alcohol forming a reaction mixture in the presence of an acidic catalyst to form the corresponding alkyl tert-butyl ether in the etherification unit;
(b) distilling the reaction mixture from the etherification unit in the first distillation unit, a C4-hydrocarbon raffinate being withdrawn as an overhead product from the first distillation unit, and the alkyl tert-butyl ether being withdrawn as a bottom product from the first distillation unit;
vaporizing the bottom product from the first distillation unit in an evaporator obtaining a vapor stream;
(c) reacting the vapor stream of step (c) in the presence of an acidic catalyst obtaining a mixture comprising isobutene and the primary alcohol in the ether cleavage unit;
(d) distilling the mixture comprising isobutene and the primary alcohol from the ether cleavage unit in the second distillation unit, isobutene being withdrawn as an overhead product from the second distillation unit, the primary alcohol being withdrawn as a bottom product from the second distillation unit and being recycled to the etherification unit;
characterized in that a purge stream containing high boiling components with a normal boiling point higher than that of the alkyl tert-butyl ether is withdrawn from the evaporator in step (c).