Catalyst systems and ethylene oligomerization method

Abstract

Disclosed herein is a catalyst system comprising (i) a heterocyclic 2-[(phosphinyl)aminyl]imine transition metal compound complex having Structure I wherein T is oxygen or sulfur, R.sup.1 and R.sup.2 are each independently a C.sub.1 to C.sub.20 organyl group consisting essentially of inert functional groups, R.sup.3 is hydrogen or a C.sub.1 to C.sub.20 organyl group, L is a C.sub.1 to C.sub.20 organylene group consisting essentially of inert functional groups, MX.sub.p represents a transition metal compound where M is a transition metal, X is a monoanion, and p is an integer from 1 to 6, Q is a neutral ligand, and q ranges from 0 to 6, and (ii) an organoaluminum compound. Also disclosed herein is a process comprising contacting (i) ethylene, (ii) a catalyst system comprising (a) a heterocyclic transition metal compound complex having Structure I as described herein and (b) an organoaluminum compound, and (iii) optionally hydrogen to form an oligomer product. ##STR00001##

Claims

1. A catalyst system comprising i) a heterocyclic 2-[(phosphinyl)aminyl]imine transition metal compound complex having Structure HCPAITMC 1 ##STR00015## wherein T is oxygen or sulfur, R.sup.1 and R.sup.2 are each independently a C.sub.1 to C.sub.20 organyl group consisting essentially of inert functional groups, R.sup.3 is hydrogen or a C.sub.1 to C.sub.20 organyl group, L is a C.sub.1 to C.sub.20 organylene group consisting essentially of inert functional groups, MX.sub.p represents a transition metal compound where M is chromium, X is a monoanion, and p is an integer from 1 to 6, Q is a neutral ligand, and q ranges from 0 to 6, and ii) are organoaluminum compound.

2. The catalyst system of claim 1, wherein the heterocyclic 2-[(phosphinyl)aminyl]imine transition metal compound complex has Structure HCPAITMC 2, Structure HCPAITMC 3, Structure HCPAITMC 4, Structure HCPAITMC 5, or Structure HCPAITMC 6 ##STR00016## wherein n is 1 or 2, T is oxygen or sulfur, R.sup.1 and R.sup.2 are each independently a C.sub.1 to C.sub.20 organyl group consisting essentially of inert functional groups, R.sup.3 is hydrogen or a C.sub.1 to C.sub.20 organyl group, R.sup.11, R.sup.12, R.sup.13, R.sup.14, R.sup.21, R.sup.22, R.sup.23, and R.sup.24 are each independently hydrogen or a C.sub.1 to C.sub.20 organyl group consisting essentially of inert functional groups, optionally R.sup.11 or R.sup.12 and R.sup.13 or R.sup.14 are joined to form a ring or ring system, MX.sub.p represents a transition metal compound where M is chromium, X is a monoanion, and p is an integer from 2 to 6, Q is a neutral ligand, and q ranges from 0 to 6.

3. The catalyst system of claim 2, wherein R.sup.11 and R.sup.21 are each independently hydrogen or a C.sub.1 to C.sub.10 alkyl group, and R.sup.12, R.sup.13, R.sup.14, R.sup.22, R.sup.23, and R.sup.24 are hydrogen.

4. The catalyst system of claim 2, wherein R.sup.3 is hydrogen.

5. The catalyst system of claim 1, wherein the transition metal compound comprises a chromium(III) carboxylate, a chromium(III) -diketonate, or a chromium(III) halide.

6. The catalyst system of claim 1, wherein the organoaluminum compound comprises an aluminoxane.

7. The catalyst system of claim 6, wherein the aluminoxane comprises methylaluminoxane, a modified methylaluminoxane, ethylaluminoxane, n-propylaluminoxane, iso-propylaluminoxane, n-butylaluminoxane, sec-butylaluminoxane, iso-butylaluminoxane, t-butyl aluminoxane, 1-pentylaluminoxane, 2-pentylaluminoxane, 3-pentylaluminoxane, iso-pentylaluminoxane, neopentylaluminoxane, or mixtures thereof.

8. The catalyst system of claim 6, wherein the aluminoxane comprises a modified methylaluminoxane.

9. The catalyst system of claim 6, wherein an aluminum of the aluminoxane to transition metal of the heterocyclic 2-[(phosphinyl)aminyl]imine transition metal compound complex molar ratio is in the range of from 10:1 to 5,000:1.

10. The catalyst system of claim 1, wherein the heterocyclic 2-[(phosphinyl)aminyl]imine transition metal compound complex has Structure HCPAITMC 2, Structure HCPAITMC 3, Structure HCPAITMC 4, Structure HCPAITMC 5, or Structure HCPAITMC 6 ##STR00017## wherein n is 1 or 2, T is oxygen or sulfur, R.sup.1 and R.sup.2 are each independently a C.sub.1 to C.sub.20 organyl group consisting essentially of inert functional groups, R.sup.3 is hydrogen, R.sup.11 and R.sup.21 are each independently hydrogen or a C.sub.1 to C.sub.10 alkyl group, R.sup.12, R.sup.13, R.sup.14, R.sup.22, R.sup.23, and R.sup.24 are hydrogen, MX.sub.p, is chromium(III) chloride, Q is a neutral ligand, q ranges from 0 to 3, the organoaluminum compound is an aluminoxane, and an aluminum of the aluminoxane to chromium of the heterocyclic 2-[(phosphinyl)aminyl])imine transition metal compound complex molar ratio is in the range of from 10:1 to 5,000:1.

11. The catalyst system of claim 10, wherein the heterocyclic 2-[(phosphinyl)aminyl]imine transition metal compound complex has Structure HCPAICr A, Structure HCPAICr B, or Structure HCPAICrC. ##STR00018##

12. A process comprising: contacting i) ethylene, ii) a catalyst system comprising (a) a heterocyclic 2-[(phosphinyl)aminyl]imine transition metal compound complex having Structure HCPAITMC 1 ##STR00019## wherein T is oxygen or sulfur, R.sup.1 and R.sup.2 are each independently a C.sub.1 to C.sub.20 organyl group consisting essentially of inert functional groups, R.sup.3 is hydrogen or a C.sub.i to C.sub.20 organyl group, L is a C.sub.1 to C.sub.20 organylene group consisting essentially of inert functional groups, MX.sub.p represents a transition metal compound where M is chromium, X is a monoanion, and p is an integer from 1 to 6, Q is a neutral ligand, q ranges from 0 to 6, and (b) an organoaluminum compound, and iii) optionally hydrogen to form an oligomer product.

13. The process of claim 12, wherein the heterocyclic 2-[(phosphinyl)aminyl]imine transition metal compound complex has Structure HCPAITMC 2, Structure HCPAITMC 3, Structure HCPAITMC 4, Structure HCPAITMC 5, or Structure HCPAITMC 6 ##STR00020## wherein n is 1 or 2, T is oxygen or sulfur, R.sup.1 and R.sup.2 are each independently a C.sub.1 to C.sub.20 organyl group consisting essentially of inert functional groups, R.sup.3 is hydrogen or a C.sub.1 to C.sub.20 organyl group, R.sup.11, R.sup.12, R.sup.13, R.sup.14, R.sup.21, R.sup.22, R.sup.23, and R.sup.24 are each independently hydrogen or a C.sub.1 to C.sub.20 organyl group consisting essentially of inert functional groups, optionally R.sup.H or R.sup.12 and R.sup.13 or R.sup.14 are joined to form a ring or ring system, MX.sub.p represents a transition metal compound where M is chromium, X is a monoanion, and p is an integer from 1 to 6, Q is a neutral ligand, and q ranges from 0 to 6.

14. The process of claim 12, wherein the process further comprises contacting the heterocyclic 2-[(phosphinyl)aminyl]imine transition metal compound complex and the organoaluminum compound to form a catalyst system mixture, and aging the catalyst system mixture in a substantial absence of ethylene to form an aged catalyst system mixture.

15. The process of claim 14, wherein the catalyst system is aged in the substantial absence of ethylene for from 5 minutes to 6 hours.

16. The process of claim 12, wherein the transition metal compound comprises a chromium(III) carboxylate, a chromium(III) -diketonate, or a chromium(III) halide.

17. The process of claim 12, wherein the organoaluminum compound comprises an aluminoxane.

18. The process of claim 12, wherein the heterocyclic 2-[(phosphinyl)aminyl]imine transition metal compound complex has Structure HCPAITMC 2, Structure HCPAITMC 3, Structure HCPAITMC 4, Structure HCPAITMC 5, or Structure HCPAITMC 6 ##STR00021## wherein n is 1 or 2, T is oxygen or sulfur, R.sup.1 and R.sup.2 are each independently a C.sub.1 to C.sub.20 organyl group consisting essentially of inert functional groups, R.sup.3 is hydrogen, R.sup.11 and R.sup.21 are each independently hydrogen or a C.sub.1 to C.sub.10 alkyl group, R.sup.12, R.sup.13, R.sup.14, R.sup.22, R.sup.23, and R.sup.24 are hydrogen, MX.sub.p is chromium(III) chloride, Q is a neutral ligand, q ranges from 0 to 6, and the organoaluminum compound is an aluminoxane.

19. The process of claim 18, wherein the oligomer product is formed at (a) an ethylene partial pressure ranging from 150 psi to 2,000 psi, (b) a hydrogen partial pressure ranging from 5 psi to 400 psi, (c) a temperature ranging from 20 C. to 150 C., and (d) an aluminum of the aluminoxane to chromium of the heterocyclic 2-[(phosphinyl)aminyl]imine transition metal compound complex molar ratio is in the range of from 10:1 to 5,000:1.

20. The process of claim 19, wherein the heterocyclic 2-[(phosphinyl)aminyl]imine transition metal compound complex has Structure HCPAICr A, Structure HCPAICr B, or Structure HCPAICr C ##STR00022##

21. The process of claim 12, wherein the oligomer product comprises at least 70 wt. % ethylene trimer, ethylene tetramer, or any combination thereof

22. The process of claim 21, wherein the ethylene trimer comprises at least 85 wt. % 1-hexene

23. The process of claim 21, wherein the ethylene tetramer comprises at least 90 wt. % 1-octene.

Description

EXAMPLES

(1) The subject matter of the present disclosure having been generally described, the following examples are given as particular aspects of the disclosure and to demonstrate the practice and advantages thereof. It is understood that the examples are given by way of illustration and are not intended to limit the specification or the claims to follow in any manner.

(2) Heterocyclic 2-[(phosphinyl)aminyl]imine chromium(III) chloride complexes HCPAICr A, HCPAICr B, and HCPAICr C were individually prepared and utilized separately as a component in an ethylene oligomerization catalyst system. The 2[(phosphinyl)aminyl] cyclic imine chromium(III) chloride complex having Structure APCICr I was prepared utilizing methods described in U.S. patent application Ser. No. 15/171,170 filed on Jun. 2, 2016, now U.S. Pat. No 10,196,328 B2, The N.sup.2-phosphinyl amidine chromium(III) chloride complex having Structure NPACr I was prepared utilizing methods described in U.S. Patent Application Publication US 2012/0309965 A1.

(3) ##STR00014##

(4) Anhydrous tetrahydrofuran, THF, was obtained from Sigma-Aldrich and stored over 13 molecular sieves until utilized. 2-amino-2-thiazoline was obtained from Acros and utilized without further treatment or purification. 2-amino benzothiazole was obtained from Sigma-Aldrich and utilized without further treatment or purification. 2-aminoxazole was obtained from Sigma-Aldrich and utilized without further treatment or purification. Chlorodiisopropylphosphine was obtained from Sigma-Aldrich and utilized without further treatment or purification. CrCl.sub.3(THF).sub.3 was obtained from Strem and utilized without further treatment or purification. MMAO-20, 7 wt. % aluminum in heptanes, was utilized as obtained from AkzoNobel Functional Chemicals B.V. Ethylbenzene, anhydrous, was obtained from Sigma-Aldrich and stored over 13 mol sieves until utilized. Cyclohexane, anhydrous, was obtain from Sigma-Aldrich and was stored over 13 mol sieves until utilized. Ethylene, from Matheson Grade cylinder supplied by Matheson, was utilized as supplied.

Example 1

Preparation of 2-[(diisopropylphosphinyl)amino imine Heterocycles

Preparation of 2-[(diisopropylphosphinyl)amino Thiazoline

(5) In an inert atmosphere glove box, 2-amino-2-thiazoline (2.0 g, 20 mmol) was suspended in diethyl ether with stirring. To the suspension was added n-butyllithium (20 mmol) dropwise over 15 minutes. This mixture was allowed to stir for 3 hours. To the resulting suspension was added chlorodiisopropylphosphine (2.9 g, 19 mmol) dropwise with stirring. The resulting mixture was allowed to stir overnight then filtered on a glass frit. The volatiles were removed from the filtrate in vacuo and the resulting yellow semi-solids were suspended and stirred in pentane resulting in white solids which were collected on a frit. The white solids were dried in vacuo then analyzed by GC-MS and confirmed as 2-[(diisopropylphosphinyl)amino thiazoline (1.04 g, 4.76 mmol).

Preparation of 2-[(diisopropylphosphinyl)amino Benzothiazole

(6) In an inert atmosphere glove box, 2-amino benzothiazole (1.0 g, 6.6 mmol) was suspended in diethyl ether with stirring. To the suspension was added n-butyllithium (6.6 mmol) dropwise over 15 minutes. This mixture was allowed to stir for 2 hours. To the resulting cloudy suspension was added chlorodiisopropylphosphine (1.0 g, 6.6 mmol) dropwise with stirring. The resulting mixture was allowed to stir overnight. The following morning, peach colored solids were filtered away on a glass frit. The volatiles were slowly evaporated from the filtrate resulting in colorless crystals. The remaining yellow filtrate was removed, the colorless crystals were analyzed by GC-MS and confirmed as 2-[(diisopropylphosphinyl)amino benzothiazole (0.522 g, 1.96 mmol).

Preparation of 2-[(diisopropylphosphinyl)amino Oxazole

(7) In an inert atmosphere glove box, 2-amino oxazole (1.0 g, 11.9 mmol) was suspended in diethyl ether with stirring. To the suspension was added n-butyllithium (11.9 mmol) dropwise over 15 minutes. This mixture was allowed to stir for 5 hours. To the resulting cloudy suspension was added chlorodiisopropylphosphine (1.8 g, 11.8 mmol) dropwise with stirring. The resulting yellow solution was allowed to stir overnight. The following morning, the resulting orange mixture was filtered on a glass frit. The volatiles were removed from the filtrate in vacuo and the resulting yellow semi-solids were suspended and stirred in a mixture of in pentane and diethyl ether. White solids were then filtered off on a frit. The yellow filtrate was dried in vacuo resulting in a yellow oil which was analyzed by GC-MS and confirmed as 2-[(diisopropylphosphinyl)amino oxazole (0.750 g, 3.75 mmol).

Example 2

Preparation of Chromium ChlorideTHF Complexes

Preparation of 2-[(diisopropylphosphinyl)amino Thiazoline Chromium(III) Chloride Tetrahydrofuran ComplexHCPAICr A

(8) In an inert atmosphere glove box, CrCl.sub.3(THF).sub.3 (0.348 g, 0.929 mmol) was suspended in tetrahydrofuran with stirring. To the suspension was added a solution of 2-[(diisopropylphosphinyl)amino thiazoline (0.214 g, 0.980 mmol) in tetrahydrofuran dropwise with stirring. The resulting suspension was allowed to stir overnight. From the resultant blue solution, the solvent was removed in vacuo. The resulting solids were stirred in diethyl ether then filtered. The blue solids were collected, and subsequently used as HCPAICr A.

Preparation of 2-[(diisopropylphosphinyl)amino Benzothiazole Chromium(III) Chloride Tetrahydrofuran ComplexHCPAICr B

(9) In an inert atmosphere glove box, CrCl.sub.3(THF).sub.3 (0.267 g, 0.713 mmol) was suspended in tetrahydrofuran with stirring. To the suspension was added 2-[(diisopropylphosphinyl)amino benzothiazole (0.200 g, 0.751 mmol) as a solid. The resulting suspension was stirred four hours. From the resultant blue solution, the solvent was removed in vacuo. The resulting solids were stirred in diethyl ether then filtered. The blue solids were collected, and subsequently used as HCPAICr B.

Preparation of 2-[(diisopropylphosphinyl)amino Oxazole Chromium(III) Chloride Tetrahydrofuran ComplexHCPAICr C

(10) In an inert atmosphere glove box, CrCl.sub.3(THF).sub.3 (0.715 g, 1.91 mmol) was suspended in tetrahydrofuran with stirring. To the suspension was added 2-[(diisopropylphosphinyl)amino oxazole (0.400 g, 2.00 mmol) as a solid. The resulting suspension was allowed to stir overnight. From the resultant blue solution, the solvent was removed in vacuo. The resulting solids were stirred in diethyl ether then filtered. The blue solids were collected, and subsequently used as HCPAICr C.

Example 3

General Ethylene Oligomerization ProcedureRuns 1-6

(11) Ethylene oligomerizations were performed using heterocyclic 2-[(phosphinyl)aminyl]imine chromium(III) chloride complexes HCPAICr A, HCPAICr B, and HCPAICr C, 2-[(phosphinyl)aminyl]cyclic imine chromium(III) chloride complex APCICr I, and N.sup.2-phosphinyl amidine chromium(III) chloride complex NPACr I using the following procedure and the amounts and conditions indicated in Table 2.

(12) In a dry box, a 20 mL glass vial was charged with the desired complex, the desired amount of catalyst system solvent, and MMAO-20 (7 wt. % Al solution in heptanes) or MMAO-3 (7 wt. % Al solution in heptanes) to provide the desired Al:Cr molar ratio. This solution was then aged for the desired time in the absence of ethylene to provide an aged catalyst system mixture. The aged catalyst system mixture was then added to 0.5 L glass charger containing 200 mL of the oligomerization solvent, cyclohexane.

(13) The glass charger was removed from the dry box and the contents charged into an evacuated 0.5 L stainless steel reactor having an internal temperature of 60 C. Hydrogen was charged to the stainless-steel reactor to the desired pressure. Ethylene was then charged to the stainless-steel reactor to the desired pressure. The reaction was allowed to proceed at the conditions indicated in Table 2 with ethylene being fed on demand to maintain the desired oligomerization pressure.

(14) At reaction completion, water cooling was applied to the 0.5 L stainless steel reactor using the internal cooling coils. When the stainless-steel reactor contents reached 35 C., the unreacted ethylene and hydrogen gas were vented from the stainless-steel reactor. A 2 mL sample of the liquid product was collected, filtered, and analyzed by GC-FID. The stainless-steel reactor solids were collected by filtering the liquid solution and cleaning the reactor walls and internal cooling coils. Table 2 provides the analysis of the oligomer product of the ethylene oligomerization and the calculated productivities and activity of the catalyst systems tested in ethylene oligomerization runs 1-6.

(15) TABLE-US-00002 TABLE 2 Ethylene Oligomerization Run # 1 2 3 4 5 6 Catalyst System Complex HCPAICr A HCPAICr B HCPAICr C HCPAICr C APCICr I NPACr I Mass Complex (mg) 3.5 3.5 2.5 2.5 2.5 3.5 mmol complex 0.0078 0.0070 0.0058 0.0058 0.0058 0.0060 mg Cr 0.4056 0.3663 0.3018 0.3018 0.3018 0.3112 Catalyst System Solvent* EB EB EB EB EB EB Catalyst System Solvent Mass (g) 1 1 1 1 1 1 MAO Type MMAO-20 MMAO-20 MMAO-20 MMAO-20 MMAO-20 MMAO-3 Mass MAO (g) 1.50 1.50 1.36 1.36 1.36 1.275 Al:Cr ratio 500 554 610 610 610 554 Catalyst System Aging Time (hours) 0.5 0.5 0.5 0.5 1.5 0.5 Ethylene Oligomerization Conditions Organic Reaction Medium** Cy Cy Cy Cy Cy Cy Organic Reaction Medium Volume (mL) 200 200 200 200 200 200 Ethylene Pressure (psi) 875 875 875 875 875 875 Hydrogen Pressure (psi) 50 50 50 50 50 50 Oligomerization Temperature ( C.) 70 70 70 70 70 70 Oligomerization Time (minutes) 35 20 20 35 20 20 Oligomer Product Liquid Oligomer Product (grams) 5 4 3 5 75 148 Polymer (grams) 0 0.72 0.06 0.17 0.66 0.09 Polymer (wt. %) 0.00% 15.17% 2.56% 3.3 0.88% 0.06 Liquid Oligomer Product Distribution Combined C.sub.6 + C.sub.8 (wt. %) 97.0 98.6 97.3 96.1 92.6 95.7 C.sub.6 (wt. %) 66.0 94.8 56.3 41.2 35.3 94.8 1-hexene (wt. % of C.sub.6 product) 93.8 96.2 91.2 88.2 78.3 99.59 Methylcyclopentane (wt. % of C.sub.6 3.0 1.3 3.9 5.6 10.0 0.03 product) Methylenecyclopentane (wt. % of C.sub.6 2.0 1.4 2.7 4.2 8.1 0.02 product) C.sub.8 (wt. %) 31.0 3.8 41.0 54.9 57.3 0.9 1-octene (wt. % of C.sub.8 product) 96.6 91.5 95.3 95.3 93.4 99.1 C.sub.10+ (wt. %) 3.0 1.4 2.7 3.9 7.8 4.3 C.sub.10 (wt. %) 2.1 1.4 2.7 2.9 4.1 4.2 C.sub.12 (wt. %) 0.9 0 0 1.0 3.3 0.1 C.sub.14+ (wt. %) 0 0 0 0 0 0.0 Ethylene Oligomerization Productivities and Activities Grams (C.sub.6 + C.sub.8)/gram Cr 12,886 10,832 11,066 15,490 228,993 454,667 Grams (C.sub.6 + C.sub.8)/gram Cr/hour 38,659 32,496 33,199 26,554 686,980 1,364,001 *EB = ethylbenzene **Cy = cyclohexane

(16) The subject matter of the present disclosure illustratively disclosed herein suitably can be practiced in the absence of any element that is not specifically disclosed herein and/or any optional element disclosed herein. While compositions and processes are described in terms of comprising, containing, or including various components or steps, the compositions and processes can also consist essentially of or consist of the various components and steps. All numbers and ranges disclosed above can vary by some amount. Whenever a numerical range with a lower limit and an upper limit is disclosed, any number and any included range falling within the range are specifically disclosed. In particular, every range of values of the form, from about a to about b, or, equivalently, from approximately a to b, or, equivalently, from approximately a-b disclosed herein is to be understood to set forth every number and range encompassed within the broader range of values.

(17) All publications, patents, and published patent applications mentioned herein are incorporated herein by reference in their entirety. The publications and patents mentioned herein can be utilized for the purpose of describing and disclosing, for example, the constructs and methodologies that are described in the publications, which might be used in connection with the presently described subject matter. The publications discussed throughout the text are provided solely for their disclosure prior to the filing date of the present application. Nothing herein is to be construed as an admission that the applicants are not entitled to antedate such disclosure by virtue of prior investigations, including but not limited to experimental results.

(18) Therefore, the subject matter of the present disclosure is well adapted to attain the ends and advantages mentioned as well as those that are inherent therein. This concludes the detailed description. The particular embodiments disclosed above are illustrative only, as the subject matter of the present disclosure can be modified and practiced in different but equivalent manners apparent to those skilled in the art having the benefit of the teachings herein. Furthermore, no limitations are intended to the details of construction or design herein shown, other than as described in the claims below. It is therefore evident that the particular embodiments disclosed above can be altered or modified and all such variations are considered within the scope and spirit of the present disclosure. Accordingly, the protection sought herein is as set forth in the claims below.