CATALYST SYSTEMS

Abstract

Catalyst systems suitable for tetramerizing ethylene to form 1-octene may include a catalyst including a reaction product of a chromium compound and a ligand having the structure according to Formula (II). In Formula (II), A and C may be independently chosen from phosphorus, arsenic, antimony, bismuth, and nitrogen; B may be a linking group between A and C; and R.sub.1, R.sub.2, R.sub.3, and R.sub.4 may be independently chosen from a (C.sub.1-C.sub.50) hydrocarbyl or a (C.sub.1-C.sub.50) heterohydrocarbyl. The catalyst system may include a co-catalyst including a reaction product of an organoaluminum compound and an antifouling compound. The antifouling compound may include one or more quaternary salts; one or more organic acids, organic acid salts, esters, anhydrides, or combinations of these; one or more chlorinated hydrocarbons, chloro-aluminum alkyls, or combinations of these; one or more polyether alcohols; or one or more non-polymeric ethers.

Claims

1. A catalyst system suitable for tetramerizing ethylene to form 1-octene, the catalyst system comprising: a catalyst comprising a reaction product of a chromium compound and a ligand having the structure:
(R.sub.1)(R.sub.2)A-B-C(R.sub.3)(R.sub.4) wherein: A and C are independently chosen from phosphorus, arsenic, antimony, bismuth, and nitrogen; B is a linking group between A and C; R.sub.1, R.sub.2, R.sub.3, and R.sub.4 are independently chosen from a (C.sub.1-C.sub.50) hydrocarbyl or a (C.sub.1-C.sub.50) heterohydrocarbyl; and a co-catalyst comprising a reaction product of an organoaluminum compound and an antifouling compound, wherein the antifouling compound comprises: one or more quaternary salts; one or more organic acids, organic acid salts, esters, anhydrides, or combinations of these; one or more chlorinated hydrocarbons, chloro-aluminum alkyls, or combinations of these; one or more polyether alcohols; or one or more non-polymeric ethers.

2. The catalyst system of claim 1, wherein the antifouling compound comprises one or more quaternary salts.

3. The catalyst system of claim 1, wherein the antifouling compound comprises one or more organic acids.

4. The catalyst system of claim 1, wherein the antifouling compound comprises one or more organic acid salts.

5. The catalyst system of claim 1, wherein the antifouling compound comprises one or more esters.

6. The catalyst system of claim 1, wherein the antifouling compound comprises one or more anhydrides.

7. The catalyst system of claim 1, wherein the antifouling compound comprises one or more chlorinated hydrocarbons.

8. The catalyst system of claim 1, wherein the antifouling compound comprises one or more chloro-aluminum alkyls.

9. The catalyst system of claim 1, wherein the antifouling compound comprises one or more polyether alcohols.

10. The catalyst system of claim 1, wherein the antifouling compound comprises one or more non-polymeric ethers.

11. The catalyst system of claim 1, wherein the chromium compound comprises one or more of an organic chromium salt, an inorganic chromium salt, and a chromium complex.

12. The catalyst system of claim 1, wherein the chromium compound comprises one or more of chromium trichloride tris-tetrahydrofuran complex, (benzene)tricarbonyl chromium, chromium (III) octanoate, chromium (III) acetylacetonoate, chromium hexacarbonyl, and chromium (III) 2-ethylhexanoate.

13. The catalyst system of claim 1, wherein the organoaluminum compound has the structure: ##STR00016## wherein R.sub.6, R.sub.7, and R.sub.8 are each selected from a hydrogen atom and a (C.sub.1-C.sub.20) hydrocarbyl group.

14. The catalyst system of claim 1, wherein the organoaluminum compound comprises one or more of trimethylaluminium, triethylaluminum, tripropylaluminum, tri-iso-butylaluminum, diisobutylaluminium hydride, trihexylaluminum, tri-n-octylaluminium, methylaluminium dichloride, ethylaluminium dichloride, dimethylaluminium chloride, diethylaluminium chloride, aluminium isopropoxide, ethylaluminiumsesquichloride, methylaluminiumsesquichloride, methylaluminoxane (MAO), ethylaluminoxane (EAO), and modified methylaluminoxane (MMAO).

15. The catalyst system of claim 1, wherein the co-catalyst comprises a reaction product of the antifouling compound and methylaluminoxane.

16. The catalyst system of claim 1, wherein the co-catalyst comprises a reaction product of the antifouling compound, methylaluminoxane, and an alkyl aluminum compound.

17. The catalyst system of claim 1, wherein the molar ratio of the antifouling compound to the organoaluminum complex is from 0.001 to 1.

18. A method for tetramerizing ethylene to form 1-octene, the method comprising contacting ethylene with a catalyst system of any of claim 1 to form a product comprising 1-octene.

19. The method of claim 18, wherein the ethylene is formed in the conditions of: a reactor pressure from 5 bar to 120 bar; and a reactor temperature from 25° C. to 180° C.

Description

EXAMPLES

[0067] The various aspects of the present disclosure will be further clarified by the following examples. The examples are illustrative in nature and should not be understood to limit the subject matter of the present disclosure.

Catalyst Production Method

[0068] In the following examples, the catalyst was produced by dissolving 0.86 milligrams (mg) of Cr(acac).sub.3 and 1.07 mg of N,N-bis(diphenylphosphino)isopropylamine (Chemical Abstracts Service (CAS) No. 60981-68-2) in 100 milliliters (ml) of anhydrous methylcyclohexane (MCH) in an inert and moisture-free environment, and mixing for 30 minutes to produce a catalyst solution.

Co-Catalyst Production Method

[0069] In the following examples, the co-catalyst was produced by mixing 480 mg of MMAO-3A (CAS No. 146905-79-5) in heptane (7 wt. % aluminum) and an antifouling compound (AFC) such that the molar ratio of the AFC to aluminum (AFC:Al) was from 0.001 to 1 or from 0.01 to 0.1.

Ethylene Tetramerization Procedure

[0070] In the following examples, an ethylene tetramerization process (also referred to as a run) was conducted using the same general procedure. Each run was conducted in a 250 milliliter (ml) autoclave reactor unit. Before each run, the autoclave reactor unit was vacuum purged with ultrapure nitrogen to remove oxygen and moisture, which may be detrimental to the ethylene tetramerization reaction, and then filled with a desired amount of anhydrous MCH as a solvent. Once the autoclave reactor unit was prepared, the catalyst solution and co-catalyst, as described previously, were separately into the autoclave reactor unit such that the molar ratio of the co-catalyst to the catalyst (Co-Cat:Cat) was approximately 0.1. Subsequently, approximately 3 bar of ultrapure molecular hydrogen was charged to the autoclave reactor unit, which was then heated to a temperature of 45° C. In order to initiate the run, 45 bar of ethylene was charged to the autoclave rector unit. Once a desired run time of 60 min. was reached, the run was terminated by injecting 2.0 ml of methanol into the autoclave reactor unit, which was then depressurized. Any solid polymer produced was collected from the autoclave reactor unit, filtered, dried overnight in an oven at 110° C., and weighed.

Example 1

[0071] In Example 1, an ethylene tetramerization process, as described previously, was conducted using an AFC having a structure according to formula (XI):

##STR00013##

[0072] The results of Example 1 are reported in Table 1.

Example 2

[0073] In Example 2, an ethylene tetramerization process, as described previously, was conducted using an AFC having a structure according to formula (XII):

##STR00014##

[0074] The results of Example 2 are reported in Table 1.

Example 3

[0075] In Example 3, an ethylene tetramerization process, as described previously, was conducted using an AFC having a structure according to formula (XIII):

##STR00015##

[0076] The results of Example 3 are reported in Table 1.

Comparative Example 4

[0077] In Comparative Example 4, an ethylene tetramerization process, as described previously, was conducted in a manner similar to Examples 1-3, but no AFC was used (i.e., the solution of MMAO-3A in heptane was injected alone). The results of Comparative Example 4 are reported in Table 1.

TABLE-US-00001 TABLE 1 Molar Ratio Activity (mol 1- 1- Cr(acac).sub.3 PNP Al (Co- 1-octene/mol Hexene Octene Polymer Example (mmol) (mmol) (mmol) Cat:Cat) catalyst/hour) (mol. %) (mol. %) (wt. %) Example 1 0.0025 0.0025 1.25 0.1 124,630 9.52 74.09 5.73 Example 2 0.0025 0.0025 1.25 0.1 113,180 9.88 74.65 6.14 Example 3 0.0025 0.0025 1.25 0.1 100,292 9.23 74.47 5.71 Comparative 0.0025 0.0025 1.25 — 102,580 10.21 74.82 8.42 Example 4 Reaction Conditions-Temperature: 45° C.; C.sub.2H.sub.4 Pressure: 45 bar; H.sub.2 Pressure: 3 bar; Run Time: 60 min

[0078] As shown in Table 1, the catalyst systems of Examples 1-3 each resulted in lower production of polymer than the catalyst system of Comparative Example 4. Accordingly, the catalyst systems of Examples 1-3 provide a benefit over the catalyst system of Comparative Example 4 by providing a relatively low polymer selectivity. Furthermore, the catalyst systems of Examples 1-3 generally provided comparable activity and selectivity for 1-octene to the catalyst system of Comparative Example 4, even surpassing the activity for 1-octene of the catalyst system of Comparative Example 4 in some cases.

[0079] In a first aspect of the present disclosure, a catalyst system suitable for tetramerizing ethylene to form 1-octene may include a catalyst comprising a reaction product of a chromium compound and a ligand having the structure according to Formula (II). In Formula (II), A and C may be independently chosen from phosphorus, arsenic, antimony, bismuth, and nitrogen; B may be a linking group between A and C; and R.sub.1, R.sub.2, R.sub.3, and R.sub.4 may be independently chosen from a (C.sub.1-C.sub.50) hydrocarbyl or a (C.sub.1-C.sub.50) heterohydrocarbyl. The catalyst system may comprise a co-catalyst comprising a reaction product of an organoaluminum compound and an antifouling compound. The antifouling compound may comprise one or more quaternary salts; one or more organic acids, organic acid salts, esters, anhydrides, or combinations of these; one or more chlorinated hydrocarbons, chloro-aluminum alkyls, or combinations of these; one or more polyether alcohols; or one or more non-polymeric ethers.

[0080] A second aspect of the present disclosure may include the first aspect, where the antifouling compound comprises one or more quaternary salts.

[0081] A third aspect of the present disclosure may include either the first or second aspect, where the antifouling compound comprises one or more organic acids.

[0082] A fourth aspect of the present disclosure may include any of the first through third aspects, where the antifouling compound comprises one or more organic acid salts.

[0083] A fifth aspect of the present disclosure may include any of the first through fourth aspects, where the antifouling compound comprises one or more esters.

[0084] A sixth aspect of the present disclosure may include any of the first through fifth aspects, where the antifouling compound comprises one or more anhydrides.

[0085] A seventh aspect of the present disclosure may include any of the first through sixth aspects, where the antifouling compound comprises one or more chlorinated hydrocarbons.

[0086] An eighth aspect of the present disclosure may include any of the first through seventh aspects, where the antifouling compound comprises one or more chloro-aluminum alkyls.

[0087] A ninth aspect of the present disclosure may include any of the first through eighth aspects, where the antifouling compound comprises one or more polyether alcohols.

[0088] A tenth aspect of the present disclosure may include any of the first through ninth aspects, where the antifouling compound comprises one or more non-polymeric ethers.

[0089] An eleventh aspect of the present disclosure may include any of the first through tenth aspects, where the chromium compound comprises one or more of an organic chromium salt, an inorganic chromium salt, and a chromium complex.

[0090] A twelfth aspect of the present disclosure may include any of the first through eleventh aspects, where the chromium compound comprises one or more of chromium trichloride tris-tetrahydrofuran complex, (benzene)tricarbonyl chromium, chromium (III) octanoate, chromium (III) acetylacetonoate, chromium hexacarbonyl, and chromium (III) 2-ethylhexanoate.

[0091] A thirteenth aspect of the present disclosure may include any of the first through twelfth aspects, where the organoaluminum compound has the structure according to formula (III) in which R.sub.6, R.sub.7, and R.sub.8 are each selected from a hydrogen atom and a (C.sub.1-C.sub.20) hydrocarbyl group.

[0092] A fourteenth aspect of the present disclosure may include any of the first through thirteenth aspects, where the organoaluminum compound comprises one or more of trimethylaluminium, triethylaluminum, tripropylaluminum, tri-iso-butylaluminum, diisobutylaluminium hydride, trihexylaluminum, tri-n-octylaluminium, methylaluminium dichloride, ethylaluminium dichloride, dimethylaluminium chloride, diethylaluminium chloride, aluminium isopropoxide, ethylaluminiumsesquichloride, methylaluminiumsesquichloride, methylaluminoxane (MAO), ethylaluminoxane (EAO), and modified methylaluminoxane (MMAO).

[0093] A fifteenth aspect of the present disclosure may include any of the first through fourteenth aspects, where the co-catalyst comprises a reaction product of the antifouling compound and methylaluminoxane.

[0094] A sixteenth aspect of the present disclosure may include any of the first through fourteenth aspects, where the co-catalyst comprises a reaction product of the antifouling compound, methylaluminoxane, and an alkyl aluminum compound.

[0095] A seventeenth aspect of the present disclosure may include any of the first through sixteenth aspects, where the molar ratio of the antifouling compound to the organoaluminum complex is from 0.001 to 1.

[0096] According to an eighteenth aspect of the present disclosure, a method for tetramerizing ethylene to form 1-octene may comprise contacting ethylene with a catalyst system of any of the first through sixteenth aspects to form a product comprising 1-octene.

[0097] A nineteenth aspect of the present disclosure may include the eighteenth aspect, where ethylene is formed in conditions of a reactor pressure from 5 bar to 120 bar; and a reactor temperature from 25° C. to 180° C.

[0098] The subject matter of the present disclosure has been described in detail and by reference to specific embodiments. It should be understood that any detailed description of a component or feature of an embodiment does not necessarily imply that the component or feature is essential to the particular embodiment or to any other embodiment. Further, it should be apparent to those skilled in the art that various modifications and variations can be made to the described embodiments without departing from the spirit and scope of the claimed subject matter.

[0099] For the purposes of describing and defining the present disclosure it is noted that the terms “about” or “approximately” are utilized in this disclosure to represent the inherent degree of uncertainty that may be attributed to any quantitative comparison, value, measurement, or other representation. The terms “about” and/or “approximately” are also utilized in this disclosure to represent the degree by which a quantitative representation may vary from a stated reference without resulting in a change in the basic function of the subject matter at issue.

[0100] It is noted that one or more of the following claims utilize the term “wherein” as a transitional phrase. For the purposes of defining the present technology, it is noted that this term is introduced in the claims as an open-ended transitional phrase that is used to introduce a recitation of a series of characteristics of the structure and should be interpreted in like manner as the more commonly used open-ended preamble term “comprising.”

[0101] It should be understood that where a first component is described as “comprising” a second component, it is contemplated that, in some embodiments, the first component “consists” or “consists essentially of” that second component. It should further be understood that where a first component is described as “comprising” a second component, it is contemplated that, in some embodiments, the first component comprises at least 10%, at least 20%, at least 30%, at least 40%, at least 50%, at least 60%, at least 70%, at least 80%, at least 90%, at least 95%, or even at least 99% that second component (where % can be weight % or molar %).

[0102] Additionally, the term “consisting essentially of” is used in this disclosure to refer to quantitative values that do not materially affect the basic and novel characteristic(s) of the disclosure. For example, a chemical composition “consisting essentially” of a particular chemical constituent or group of chemical constituents should be understood to mean that the composition includes at least about 99.5% of a that particular chemical constituent or group of chemical constituents.

[0103] It should be understood that any two quantitative values assigned to a property may constitute a range of that property, and all combinations of ranges formed from all stated quantitative values of a given property are contemplated in this disclosure. It should be appreciated that compositional ranges of a chemical constituent in a composition should be appreciated as containing, in some embodiments, a mixture of isomers of that constituent. In additional embodiments, the chemical compounds may be present in alternative forms such as derivatives, salts, hydroxides, etc.