Method for preparing a catalyst composition for oligomerization of ethylene and respective catalyst composition pre-formation unit

1. A method for preparing a catalyst composition for the oligomerization of ethylene comprising the steps:

a) reacting in a first solvent, a co-catalyst and a modifier, wherein the co-catalyst is triethylaluminum, and wherein the modifier is tetraphenylphosphonium chloride to form a reaction product;

b) adding a chromium compound and a ligand to the first solution of the reaction product obtained in step a) to obtain a second solution; and

c) mixing the second solution obtained in step b) for 10 seconds to 5 hours by pressurizing with ethylene at a pressure of 30 bar and at a temperature of 50° C.;

wherein the first solvent is toluene;

wherein the second solvent is an aromatic or aliphatic solvent or mixtures thereof;

wherein the chromium compound is selected from organic or inorganic salts, coordination complexes and organometallic complexes of Cr(II) or Cr(III);

wherein the molar ligand/Cr ratio is from 0.5 to 50; and

wherein the ligand has the general structure R 1 R 2 P—N(R 3 )—P(R 4 )—N(R 5 )—H, wherein R 1 , R 2 , R 3 , R 4 and R 5 are independently selected from halogen, amino, trimethylsilyl, C 1 -C 10 -alkyl, substituted C 1 -C 10 alkyl, aryl and substituted aryl;

wherein the reaction product is a liquid clathrate having the formula

[PPh 4 ]Cl+2Al(CH 2 CH 3 ) 3 +13C 7 H 8 →[PPh 4 ][Al 2 (CH 2 CH 3 ) 6 Cl]*(C 7 H 8 ) 13 .

2. The method according to claim 1 , wherein the chromium compound is an inorganic chromium salt.

3. The method according to claim 2 , wherein the chromium compound is selected from CrC 3 (THF) 3 , Cr(III)acetylacetonate, Cr(III)octanoate, chromium hexacarbonyl, Cr(III)-2-ethylhexanoate, benzene(tricarbonyl)-chromium or Cr(III)chloride.

4. The method according to claim 1 , wherein the ligand has the general structure R 1 R 2 P—N(R 3 )—P(R 4 )—N(R 5 )—H, wherein R 1 , R 2 , R 3 , R 4 and R 5 are independently selected from C 1 -C 10 -alkyl.

5. The method according to claim 1 , wherein wherein R 1 and R 5 are independently selected from C 1 -C 10-alkyl.

6. The method according to claim 5 , wherein the chromium compound and the ligand are added to the first solution obtained in step a) simultaneously, dissolved in a second solvent.

7. The method according to claim 5 , wherein the ligand has the general structure R 1 R 2 P—N(R 3 )—P(R 4 )—N(R 5 )—H, wherein R 4 is C 1 -C 10 -alkyl.

8. The method according to claim 1 , wherein the second solvent is toluene.

9. The method according to claim 1 , wherein the ligand has the general structure R 1 R 2 P—N(R 3 )—P(R 4 )—N(R 5 )—H, wherein R 1 is C 1 -C 10 -alkyl.

10. The method according to claim 1 , wherein R 1 and R 2 are the.

11. The method according to claim 1 , wherein the molar Al/Cr ratio is from 1.0 to 1,000.

12. The method according to claim 1 , wherein the molar modifier/Cr ratio is from 0.1 to 100.

13. The method according to claim 1 , wherein the ligand has the general structure R 1 R 2 P—N(R 3 )—P(R 4 )—N(R 5 )—H, wherein R 2 is C 1 -C 10 -alkyl.

14. The method according to claim 1 , wherein the ligand has the general structure R 1 R 2 P—N(R 3 )—P(R 4 )—N(R 5 )—H, wherein R 3 is C 1 -C 10 -alky.

15. The method according to claim 1 , wherein the ligand has the general structure R 1 R 2 P—N(R 3 )—P(R 4 )—N(R 5 )—H, wherein R 5 is C 1 -C 10 -alkyl.

16. The method according to claim 1 , wherein the second solution obtained in step b) is mixed for 0.5 hours to 2.5 hours.

17. The method according to claim 1 , wherein the ligand has the general structure R 1 R 2 P—N(R 3 )—P(R 4 )—N(R 5 )-H wherein R 3 is C1-C10-alkyl.