Evonik Oxeno Gmbh

Evonik Degussa Gmbh

Walter Luh

Markus Winterberg

Dietrich Maschmeyer

Franz Nierlich

Horst-Werner Zanthoff

Wilfried Büschken

Stephan Houbrechts

Silvia Santiago Fernandez

Dirk Roettger

Holger Wiederhold

Armin Matthias Rix

Reiner Bukohl

Christian Boeing

Gunnar Schilling

Georg Skillas

Christian Böing

Rainer Bukohl

Dirk RÖTTGER

Dirk Röttger

A process for preparing isobutene by dissociation of MTBE, including: a) reaction of isobutene-containing hydrocarbon mixtures, with methanol, present in one or more methanol-containing streams, over acidic ion exchangers to give a stream, containing MTBE and TBA; b) separation of a stream containing MTBE and TBA, from a stream by distillation; c) dissociation of a stream in the gas phase over a heterogeneous catalyst to give a stream containing at least isobutene, methanol, MTBE and water and possibly TBA, d) separation of a stream by distillation to give a stream containing in each case more than 50% by mass of the amounts of methanol, TBA and water present in another stream and a stream containing isobutene, e) separation of water from stream to below 1% by mass by distillation to give a stream, f) total or partial recirculation of the methanol-containing stream.

Preparation of isobutene by dissociation of MTBE

A process for preparing isobutene including cleaving a mixture obtained from an MTBE-containing feedstock and/or an MTBE-containing stream, affording a stream of reaction products consisting of isobutene, methanol, MTBE and by-products, the latter consisting of

Process for preparing isobutene by cleaving MTBE-containing mixtures

A process for the dissociation of methyl tert-butyl ether (MTBE), which includes at least

Process for the dissociation of MTBE

Isobutene is prepared by dissociation of MTBE in the gas phase, by a) fractional distillation of an MTBE-containing stream comprising feed MTBE (I) and a recycle stream (VIII) to give an MTBE-containing overhead stream (II) and a bottom stream (III) having a boiling point higher than MTBE, b) catalytic dissociation of the overhead stream (II) obtained in step a) to give a dissociation product (IV), c) separation by distillation of the dissociation product (IV) obtained in step b) into an overhead stream (V) comprising more than 90% by mass of isobutene and a bottom stream (VI) comprising diisobutene, MTBE and more than 50% of the methanol present in the dissociation product (IV), d) fractional distillation of the bottom stream obtained in step c) under conditions under which the methanol is obtained as bottom product (VII) and more than 99% of the MTBE is obtained in the overhead product (VIII), and e) recirculation of the overhead product (VIII) to step a).

Isobutene is prepared by a process in which a) an MTBE-containing stream I is separated by distillation into an MTBE-containing overhead stream II and a bottom stream III which comprises compounds having boiling points higher than that of MTBE; and b) the MTBE present in the overhead stream II is dissociated over a catalyst to give a dissociation product IV; wherein the stream I has a proportion of 2-methoxybutane (MSBE) of greater than 1000 ppm by mass, based on MTBE, and wherein the separation by distillation in step a) and/or the dissociation in step b) is carried out so that the dissociation product IV has a concentration of less than 1000 ppm by mass of linear butenes, based on a C-olefin fraction.

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Marl, Germany

Walter Luh