Process for oligomerizing olefins

1. A process for oligomerizing an unsaturated hydrocarbon mixture, the process comprising oligomerizing an unsaturated hydrocarbon mixture in the presence of a catalyst, comprising:

a) at least one support material selected from the group consisting of silicon dioxide, aluminium oxide, magnesium oxide, zirconium oxide, mixed oxides thereof, activated carbon, and carbon nanotubes, wherein hydroxyl groups on a surface of the support material are dehydroxylated, protected with organosilicon radicals, or both;

b) an ionic liquid;

c) a catalytically active composition comprising nickel; and

d) an activator comprising a Lewis acid with alkylating properties,

wherein the iso index obtained by oligomerizing the unsaturated hydrocarbon mixture is less than 1.

2. The process of claim 1 , wherein the ionic liquid comprises:

at least one anion selected from the group consisting of tetrafluoroborate, hexafluorophosphate, dicyanamide, bistrifluoromethylsulphonylamide, tricyanomethide, tetracyanoborate, a halide, hexafluoroantimonate, hexafluoroarsenate, sulphate, tosylate, nonaflate, tris(pentafluoroethyl)trifluorophosphate, thiocyanate, carbonate, [R″—COO] − , [R′—SO 3 ] − , [R′PO 4 R″] − and [(R′—SO 2 ) 2 N] − , wherein R′ and R″ independently represent an identical or non-identical, linear or branched, 1- to 12 carbon-atom-containing, aliphatic or alicyclic alkyl radical or a C 5 -C 18 substituted aryl, C 5 -C 18 substituted aryl-C 1 -C 6 -alkyl or C 1 -C 6 -alkyl-C 5 -C 18 substituted aryl radical, optionally substituted with at least one halogen atom; and

at least one cation selected from the group consisting of:

a quaternary ammonium cation of formula [NR 1 R 2 R 3 R 4 ] + ;

a phosphonium cation of formula [PR 1 R 2 R 3 R 4 ] + ;

an imidazolium cation of formula (I):

wherein the imidazole nucleus is optionally substituted with at least one group selected from the group consisting of a C 1 -C 6 alkyl, a C 1 -C 6 alkoxy, a C 1 -C 6 substituted aminoalkyl, a C 5 -C 12 substituted aryl, and a C 5 -C 12 substituted aryl-C 1 -C 6 alkyl;

a pyridinium cation of formula (II):

wherein the pyridine nucleus is optionally substituted with at least one group selected from the group consisting of a C 1 -C 6 alkyl, a C 1 -C 6 alkoxy, a C 1 -C 6 substituted aminoalkyl, a C 5 -C 12 substituted aryl, and a C 5 -C 12 substituted aryl-C 1 -C 6 alkyl;

a pyrazolium cation of formula (III):

wherein the pyrazole nucleus is optionally substituted with at least one group selected from the group consisting of a C 1 -C 6 alkyl, a C 1 -C 6 alkoxy, a C 1 -C 6 substituted aminoalkyl, a C 5 -C 12 substituted aryl, and a C 5 -C 12 substituted aryl-C 1 -C 6 alkyl; and

a triazolium cation of formula (IV):

wherein the triazole nucleus is optionally substituted with at least one group selected from the group consisting of a C 1 -C 6 alkyl, a C 1 -C 6 alkoxy, a C 1 -C 6 substituted aminoalkyl, a C 5 -C 12 substituted aryl, and a C 5 -C 12 substituted aryl-C 1 -C 6 alkyl

wherein:

the radicals R 1 , R 2 , R 3 are independently selected from the group consisting of:

hydrogen;

a linear or branched, saturated or unsaturated, aliphatic or alicyclic alkyl group having 1 to 20 carbon atoms;

a heteroaryl group,

a heteroaryl-C 1 -C 6 alkyl group having 3 to 8 carbon atoms in the heteroaryl radical and at least one heteroatom selected from the group consisting of N, O and S, optionally substituted with at least one group selected from the group consisting of a C 1 -C 6 alkyl group, and a halogen atom;

an aryl group; and

an aryl-C 1 -C 6 alkyl group having 5 to 12 carbon atoms in the aryl radical, optionally substituted by at least one C 1 -C 6 alkyl group, halogen atom, or both;

the radical R 4 is selected from the group consisting of:

a linear or branched, saturated or unsaturated, aliphatic or alicyclic alkyl group having 1 to 20 carbon atoms;

a heteroaryl-C 1 -C 6 alkyl group having 4 to 8 carbon atoms in the aryl radical and at least one heteroatom selected from the group consisting of N, O and S, optionally substituted with at least one C 1 -C 6 alkyl group, halogen atom, or both; and

an aryl-C 1 -C 6 alkyl group having 5 to 12 carbon atoms in the aryl radical, optionally substituted with at least one C 1 -C 6 alkyl group, halogen atom, or both.

3. The process of claim 1 , wherein the catalytically active composition comprises nickel in a form soluble with the ionic liquid, and in a 0 to +2 oxidation state.

4. The process of claim 3 , wherein the catalytically active composition comprises NiCl 2 (P(Ph) 3 ) 2 .

5. The process of claim 1 , wherein the activator comprises an organic aluminium compound of formula Al 2 X n R 6-n , wherein:

n=0-6;

X=Cl − or Br − ; and

R=C 1 -C 6 alkyl, C 5 -C 12 cycloalkyl, or a mixture thereof.

6. The process of claim 1 , wherein the activator comprises ethylaluminium dichloride.

7. The process of claim 1 , wherein the ionic liquid comprises 1-butyl-3-methylimidazolium chloride and aluminium chloride.

8. The process of claim 1 , wherein the ionic liquid comprises 1-ethyl-3-methylimidazolium tris(pentafluoroethyl)trifluorophosphate.

9. The process of claim 1 , wherein the at least one support material comprises silicon dioxide having a particle size of 0.063 to 0.2 mm, and a BET surface area of 250 to 1000 m 2 /g, determined in accordance with DIN 66131 and 66132.

10. The process of claim 1 , wherein the at least one support material comprises silicon dioxide, and a mass ratio of the ionic liquid to the support material is from 0.012 to 1.255.

11. The process of claim 2 , wherein the at least one support material comprises silicon dioxide which has been dehydroxylated, and a mass ratio of the ionic liquid to the support material is from 0.007 to 0.674.

12. The process of claim 2 , wherein the at least one support material comprises activated carbon having a BET surface area of between 1000 m 2 /g and 4000 m 2 /g as determined in accordance with DIN 66131 and 66132, and a mass ratio of the ionic liquid to the support material is from 0.022 to 2.171.

13. The process of claim 1 , wherein the unsaturated hydrocarbon mixture comprises a stream comprising an olefin having three to five carbon atoms.

14. The process of claim 1 , wherein the unsaturated hydrocarbon mixture comprises a stream comprising a linear C4 olefin and a saturated hydrocarbon.

15. The process of claim 1 , wherein the unsaturated hydrocarbon mixture comprises a stream comprising a mass fraction of between 50% and 80% of a saturated hydrocarbon and a linear C4 olefin.

16. The process of claim 2 , wherein the at least one support material comprises silicon dioxide, and a mass ratio of the ionic liquid to the silicon dioxide is from 0.012 to 1.255.

17. The process of claim 1 , wherein the hydroxyl groups on a surface of the support material are protected with organosilicon radicals.