Processes for reducing the loss of catalyst activity of a Ziegler-Natta catalyst

Patent metadata

Field	Value
Publication number	US-11311870-B2
Application number	US-201716484234-A
Country	US
Kind code	B2
Filing date	Dec 13, 2017
Priority date	Feb 7, 2017
Publication date	Apr 26, 2022
Grant date	Apr 26, 2022

Abstract

A process for reducing the loss of catalyst activity of a Ziegler-Natta catalyst is provided. The process includes preparing a Ziegler-Natta (ZN) catalyst by contacting the ZN catalyst with at least one aluminum alkyl compound to produce a reduced ZN catalyst and storing and/or transporting the reduced ZN catalyst for at least 20 days at a temperature of 25° C. or less. The reduced ZN catalyst may be used for polymerizing polyolefin polymers.

First claim

What is claimed is:

1. A process for reducing the loss of catalyst activity of a Ziegler-Natta catalyst, the process comprising:
a) preparing a Ziegler-Natta (ZN) catalyst by contacting the ZN catalyst with at least one aluminum alkyl compound to produce a reduced ZN catalyst;
wherein the preparing further comprises providing a precursor composition of the ZN catalyst comprising at least one titanium compound;

contacting the at least one titanium compound in the precursor composition with the aluminum alkyl compound in a hydrocarbon solvent using a molar ratio of the aluminum alkyl compound to the at least one titanium compound in a range from 4:1 to 8:1, where the aluminum alkyl compound converts the at least one titanium compound in the precursor composition into a modified state of the ZN catalyst; and
removing at least a portion of the aluminum alkyl compound in the hydrocarbon solvent not consumed in converting the at least one titanium compound into the modified state
b) optionally, drying the reduced ZN catalyst; and
c) storing and/or transporting the reduced ZN catalyst for at least 20 days at a temperature of 15° C. or less.

2. The process of claim 1 , wherein the reduced ZN catalyst has substantially the same catalyst activity during the storing and/or transporting.

3. The process of claim 1 , wherein the reduced ZN catalyst comprises a T0 catalyst activity at the beginning of the storing and/or transporting and a T1 catalyst activity at the end of the storing and/or transporting, and wherein the T1 catalyst activity is at least 75% of the T0 catalyst activity.

4. The process of claim 1 , wherein the reduced ZN catalyst comprises a T0 catalyst activity at the beginning of the storing and/or transporting and a T1 catalyst activity at the end of the storing and/or transporting, and wherein the T1 catalyst activity is at least 85% of the T0 catalyst activity.

5. The process of claim 1 , wherein the storing and/or transporting of the reduced ZN catalyst is for at least 30 days.

6. The process of claim 1 , wherein the storing and/or transporting of the reduced ZN catalyst is for at least 60 days.

7. The process of claim 1 , wherein the storing and/or transporting of the reduced ZN catalyst is for at least 90 days.

8. The process of claim 1 , wherein the storing and/or transporting of the reduced ZN catalyst is at a temperature of 20° C. or less.

9. The process of claim 1 , wherein the storing and/or transporting of the reduced ZN catalyst is at a temperature of 10° C. or less.

10. The process of claim 1 , wherein the aluminum alkyl compound is selected from the group consisting of at least one of tri-n-hexyl aluminum, triethyl aluminum, diethyl aluminum chloride, trimethyl aluminum, dimethyl aluminum chloride, methyl aluminum dichloride triisobutyl aluminum, tri-n-butyl aluminum, diisobutyl aluminum chloride, isobutyl aluminum dichloride, (C2H5)AlCl2, (C2H5O)AlCl2, (C6H5)AlCl2, (C6H5O)AlCl2, (C6H12O)AlCl2, and combinations thereof.

11. The process of claim 1 , wherein the hydrocarbon solvent is selected from the group consisting of at least one of isopentane, hexane, heptane, toluene, xylene, naptha, and combinations thereof.

12. The process of claim 1 , wherein the hydrocarbon solvent is an aliphatic mineral oil.

13. The process of claim 1 , wherein providing the precursor composition further comprises precipitating at least one titanium compound on a carrier material.

14. The process of claim 1 , wherein the at least one titanium compound has the formula Ti(OR)aXb, wherein R is selected from the group consisting of a C1 to C25 aliphatic or aromatic, substituted or unsubstituted, hydrocarbyl group; X is selected from the group consisting of Cl, Br, I, and combinations thereof; a is selected from the group consisting of 0, 1 and 2; b is selected from the group 1, 2, 3, and 4; and a+b=3 or 4.

15. The process of claim 1 , wherein the at least one titanium compound is selected from the group consisting of at least one of TiCl3, TiCl4, Ti(OCH3)Cl3, Ti(OC6H5)Cl3, Ti(OCOCH3)Cl3, Ti(OCOC6H5)Cl3, and combinations thereof.

16. The process of claim 13 , further comprising precipitating at least one magnesium compound with the at least one titanium compound on the carrier material.

17. The process of claim 16 , wherein the at least one magnesium compound has the formula MgX2, wherein X is selected from the group consisting of Cl, Br, I, and combinations thereof.

18. A process for polymerizing polyolefin polymers, the process comprising contacting one or more olefin monomers under polymerizable conditions with a reduced ZN catalyst of claim 1 and recovering the polyolefin polymers.

Assignees

• Exxonmobil Chemical Patents Inc

Inventors

• Smith Edward F
• Vaughan George A
• Awe Michael
• Sollen James R
• Cooke Ronald N
• Rajput Sateesh K
• Ali Ahmed H

Classifications

• C08F4/655

  with aluminium or compounds thereof · CPC title

• C08F10/02

  Ethene · CPC title

• C08F10/06

  Propene · CPC title

• B01J31/26

  containing in addition, inorganic metal compounds not provided for in groups B01J31/02 - B01J31/24 · CPC title

• B01J38/00 Primary

  Regeneration or reactivation of catalysts, in general · CPC title