Process for oligomerization of isobutene

Abstract

The present invention provides a process for oligomerization of isobutene by conversion of an isobutene-containing hydrocarbon stream over an acid catalyst in at least one reaction stage, wherein a particular ratio of recycle to feed is employed. Figure 1

Claims

A process for producing diisobutene by oligomerization of isobutene over an acid catalyst in at least one reaction stage which in each case contains at least one reactor and at least one distillation column, whereinan isobutene-containing input stream which comprises an isobutene-containing hydrocarbon stream as feed and a recirculated stream as recycle is converted in the at least one reactor of the at least one reaction stage to obtain a product mixture containing at least the diisobutene formed having a proportion of 2,4,4-trimethylpent-1-ene of at least 75 mol% and unconverted isobutene, and the obtained product mixture is supplied to the at least one distillation column,at the top of the distillation column a residual hydrocarbon stream depleted in the diisobutene formed based on the obtained product mixture is withdrawn and at least partially recirculated to the at least one reactor as recycle, characterized in that the ratio of recycle to feed is at least 4. The process according to claim 1, wherein the ratio of recycle to feed is at least 5. The process according to claim 2, wherein the ratio of recycle to feed is at least 6.The process according to any of claims 1 to 3, wherein the isobutene-containing hydrocarbon stream is a C4-hydrocarbon stream. The process according to any of claims 1 to 3, wherein the isobutene-containing hydrocarbon stream is a pure isobutene stream. The process according to claim 1, wherein the residual hydrocarbon stream withdrawn at the top of the column is completely recirculated to the at least one reactor. The process according to claim 1, wherein a reaction stage comprises at least two reactors which are connected in series or parallel relative to one another.The process according to claim 1, wherein the oligomerization is performed in the liquid phase. The process according to claim 1, wherein the acid catalyst is an acidic ion exchange resin in which a portion of the acidic protons have been exchanged for metal ions. The process according to claim 9, wherein 0.1% to 70% of the acidic protons of the ion exchanger have been exchanged for metal ions.The process according to claim 9, wherein the metal ions are ions of the alkali metals, alkaline earth metals or rare earths or combination thereof. The process according to claim 1, wherein the reactor is a flow reactor including a fixed bed reactor, a tube bundle reactor, a continuous stirred tank reactor or a loop reactor. The process according to claim 1, characterized in that the at least one reactor employed in the process is operated adiabatically, polytropically or virtually isothermally using a coolant. The process according to claim 1, wherein the oligomerization is performed at a temperature between 5°C and 160°C. The process according to claim 1, wherein the first reaction stage is run with a total feed of the isobutene-containing input stream of at least 2.5 t per t of catalyst and hour (h) (unit t / (t*h)). 

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