Oligomerization of isobutene in N-butenic hydrocarbon streams

1. A process for oligomerizing isobutene, comprising:

oligomerizing isobutene in the presence of n-butene over a solid, acidic ion exchanger having acidic protons; wherein at least one acidic proton of said ion exchanger has been exchanged for a metal ion.

2. The process according to claim 1 , wherein from 0.1 to 30% of said acidic protons of the ion exchanger have been exchanged for metal ions.

3. The process according to claim 1 , wherein an isobutenic hydrocarbon mixture comprising isobutene, 1 -butene, 2-butene and butanes is used for said oligomerizing.

4. The process according to claim 1 , wherein the metal ions are ions selected from the group consisting of alkali metals, alkaline earth metals, rare earth metals and mixtures thereof.

5. The process according to claim 3 , wherein said isobutenic hydrocarbon mixture is at least partially in the liquid phase during said oligomerizing.

6. The process according to claim 1 , wherein said oligomerizing is carried out at a temperature of from 5 to 160° C.

7. The process according to claim 3 , wherein less than 5 mol% of said 1 -butene is isomerized to 2-butene.

8. The process according to claim 1 , wherein an effluent of said oligomerizing is fractionated into C 8 -olefins and C 4 -olefins.

9. The process according to claim 8 , wherein isobutene is present in said C 4 -olefinic fraction; and

wherein said isobutene is etherified with an alcohol in at least one further reaction stage.

10. The process according to claim 8 , wherein the C 8 -olefinic fraction is hydrogenated to give saturated hydrocarbons.

11. The process according to claim 1 , wherein said ion exchanger is a solid sulfonated ion exchange resins in which from 0.1 to 60% of the acidic protons of the sulfonic acid groups have been exchanged for metal ions.

12. The process according to claim 1 , wherein an ion exchange capacity of said ion exchange resin is between 1 and 2 mol.

13. The process according to claim 1 , wherein a pore volume of said ion exchange resin is from 30 to 60 ml/g.

14. The process according to claim 1 , wherein a particle size of said ion exchange resin is between 500 μm and 1500 μm.

15. A process for preparing 1-butene from C 4 -hydrocarbon comprising:

converting a C 4 -hydrocarbon mixture over an acidic, solid ion exchanger having acidic protons;

wherein at least one acidic protons of said ion exchanger has been exchanged for a metal ion, thereby obtaining a reaction product; and

wherein the 1 -butene is removed from the reaction product by distillation.

16. The process of claim 15 , wherein from 0.1 to 30% of said acidic protons of the ion exchanger have been exchanged for metal ions.

17. The process of claim 16 , wherein the C 4 -hydrocarbon mixture comprising at least one component selected from the group consisting of isobutene, 1 -butene, 2-butene, butanes is used for oligomerizing.