Basf Se Corporation

Omv Downstream Gmbh

Suman Thotla

Gerrit Waters

Hans-Guenter Wagner

Thomas Roussiere

Markus Neudert

Michael Huebner

Stefan Iselborn

Pawel Czajka

Kai-Uwe Wemhöner

Jürgen Popp

Wolfgang Siegel

Randolf Hugo

Stephan Freyer

Gabriele Iffland

Jens Wittenberg

Stefanie Demming

Yvonne Hoelzl

Randolph Hugo

Till Christian Brueggemann

Christian Brueggemann

Till Christian BRÜGGEMANN

The invention relates to 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 mixture with the primary alcohol 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reaction mixture () from the etherification unit () in the first distillation unit (), a C4-hydrocarbon raffinate being withdrawn as the overhead product (), and the alkyl tert-butyl ether being withdrawn as the bottom product (); (c) vaporizing the bottom product from the first distillation unit () in an evaporator () obtaining a vapor stream (); (d) reacting the vapor stream () of step (c) in the presence of an acidic catalyst obtaining isobutene and the primary alcohol as reaction products in the ether cleavage unit (); (e) distilling the reaction mixture () from the ether cleavage unit () in the second distillation unit (), isobutene being withdrawn as the overhead product (), the primary alcohol and diisobutene being withdrawn as the bottom product () and being recycled to the etherification unit (); wherein a purge stream () containing high boiling components with a normal boiling point higher than that of the alkyl tert-butyl ether is withdrawn from the evaporator () in step (c).

Process for obtaining isobutene from a C4-hydrocarbon mixture

A process for the purification of isobutene from a C4 stream with at least 1-butene, 2-butene, isobutane and isobutene includes isomerizing 1-butene from a stream of material which is concentrated in isobutane and isobutene obtained from the C4 stream into 2-butene, using a catalyst in an isomerization reactor; supplying a product stream from the isomerization reactor to a rectification column; and providing a stream of material which is concentrated in isobutene. A processing facility is utilized for the purification of isobutene from the C4 stream.

Method for purifying isobutene from a C4 stream and process system therefor

The invention relates to 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 mixture with the primary alcohol in the presence of an acidic catalyst to form the corresponding alkyl tert-butyl ether as an intermediate product and diisobutene as a by-product 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 the overhead product (), the alkyl tert-butyl ether and diisobutene being withdrawn as the liquid or vaporous bottom product (), and vaporizing the bottom product () if it is withdrawn as a liquid; (c) reacting the vaporous bottom product () in the presence of an acidic catalyst obtaining isobutene and the primary alcohol as reaction products in the ether cleavage unit (); (d) distilling the reaction mixture () from the ether cleavage unit () in the second distillation unit (), isobutene being withdrawn as the overhead product (), the primary alcohol and diisobutene being withdrawn as the bottom product () and being recycled to the etherification unit (); the plant further comprising a byproduct separation unit () being fed by a bottom purge stream () of the first distillation unit () and/or by a part of the bottom product of the second distillation unit (), this feed stream () being split up in at least three byproduct streams wherein a first byproduct stream () is rich in diisobutene, a second byproduct stream () is rich in the primary alcohol, and a third byproduct stream () is rich in components with a normal boiling point higher than 110° C.

The invention relates to 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 mixture with the primary alcohol in the presence of an acidic catalyst to form the corresponding alkyl tert-butyl ether as an intermediate product and diisobutene as a by-product 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 the overhead product (), the alkyl tert-butyl ether and diisobutene being withdrawn as the liquid or vaporous bottom product (), and vaporizing the bottom product () if it is withdrawn as a liquid: (c) reacting the vaporous bottom product () in the presence of an acidic catalyst obtaining isobutene and the primary alcohol as reaction products in the ether cleavage unit (): (d) distilling the reaction mixture () from the ether cleavage unit () in the second distillation unit (), isobutene being withdrawn as the overhead product (), the primary alcohol and diisobutene being withdrawn as the bottom product () and being recycled to the etherification unit (); the plant further comprising a byproduct separation unit () being fed by a bottom purge stream () of the first distillation unit () and/or by a part of the bottom product of the second distillation unit (), wherein a diisobutene product stream rich in diisobutene is separated from this feed stream ().

The invention relates to a process for starting up a plant for removing isobutene from an isobutene-containing C4-hydrocarbon mixture, the plant comprising an etherification unit containing moist acidic ion exchange resin, a first distillation unit, an ether cleavage unit, and a second distillation unit. The invention further relates to a process for shutting down the plant from a stationary operation mode.

Process for starting up and shutting down a plant for removing isobutene from a C4-hydrocarbon mixture

The invention relates to a process for continuously preparing di-C-alkyl succinates by reacting succinic acid with an C-alkanol in the presence of a fixed-bed heterogeneous acidic esterification catalyst in a tubular reactor at a temperature in the range of from 60 to 100&#xb0; C., wherein a mixture, comprising succinic acid, C-alkanol, mono-C-alkyl succinate, di-C-alkyl succinate and water, is formed in a mixing stage and fed to the entrance of the tubular reactor, and wherein 5 to 75% of the outlet flow rate of the tubular reactor are recycled directly to the mixing stage as a recycle stream, and the molar ratio of C-alkanol to succinic acid added to the mixing zone, and not including the C-alkanol and succinic acid at the recycle stream, being in the range of from 2.0 to 9.5. The invention furthermore relates to a process for separating the reactor effluent of an esterification of succinic acid with an C-alkanol to give di-C1-3-alkyl succinates by distillation, wherein the separation is performed in a divided wall column in which C-alkanol and water are removed in a top draw of the column, di-C-alkyl succinate is removed in a side draw of the column, and wherein mono-C-alkyl succinate and succinic acid are removed in a bottom draw of the column.

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The invention relates to a process for continuously preparing di-C-alkyl succinates by reacting succinic acid with an C-alkanol in the presence of a fixed-bed heterogeneous acidic esterification catalyst in a tubular reactor at a temperature in the range of from 60 to 100&#xb0; C., wherein a mixture, comprising succinic acid, C-alkanol, mono-C-alkyl succinate, di-C-alkyl succinate and water, is formed in a mixing stage and fed to the entrance of the tubular reactor, and wherein 5 to 75% of the outlet flow rate of the tubular reactor are recycled directly to the mixing stage as a recycle stream, and the molar ratio of C-alkanol to succinic acid added to the mixing zone, and not including the C-alkanol and succinic acid at the recycle stream, being in the range of from 2.0 to 9.5. The invention furthermore relates to a process for separating the reactor effluent of an esterification of succinic acid with an C-alkanol to give di-C-alkyl succinates by distillation, wherein the separation is performed in a divided wall column in which C-alkanol and water are removed in a top draw of the column, di-C-alkyl succinate is removed in a side draw of the column, and wherein mono-C-alkyl succinate and succinic acid are removed in a bottom draw of the column.

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Mannheim, Germany

Suman Thotla