Utilization of linear alpha olefins in the production of metallocene catalyzed poly-alpha olefins

Patent metadata

Field	Value
Publication number	US-9469704-B2
Application number	US-34183008-A
Country	US
Kind code	B2
Filing date	Dec 22, 2008
Priority date	Jan 31, 2008
Publication date	Oct 18, 2016
Grant date	Oct 18, 2016

Abstract

The invention is directed to a process for the preparation of lubricant base stocks by contacting alphaolefin feedstocks with single-site metallocene catalysts and recycling unconverted monomers, characterized by a purge step in the recycle.

First claim

What is claimed is:

1. A process to prepare a PAO base stock characterized by a Kinematic Viscosity (K.V.) measured according to ASTM D445 at 100° C. of between 3 cSt and 10,000 cSt, comprising a step of contacting a single-site metallocene catalyst system with a feedstock comprising one or more fresh monomers selected from C 4 to C 18 alpha olefins and a recycled stream comprising un-reacted alpha-olefins, wherein said feedstock in said contacting step comprises 1 to 30% recycled un-reacted alpha-olefin, on a weight basis of the total olefin feed, and wherein said recycled stream is generated from the reactor effluent after separation from catalyst components and a lubricant-range PAO of at least C 26 , wherein said process includes a purge in the amount of 1.0 wt % up to 80 wt % of said recycled stream, and the polymerization temperature is reduced by up to 5° C. after the recycled stream is first introduced into the reactor.

2. The process of claim 1 , wherein said purge consists of 5 wt % to 60 wt % of said recycled stream.

3. The process of claim 1 , wherein said purge consists of 10 wt % to 50 wt % of said recycled stream.

4. The process according to claim 1 , wherein said PAO base stock is characterized by a KV 100 of greater than 3 cSt to about 3,000 cSt and a shear stability as tested by TRB at 20 hrs of less then 4% viscosity change, wherein said contacting occurs in a continuously stirred tank reactor (CSTR).

5. The process according to claim 1 , wherein said PAO base stock is characterized by a KV 100 of greater than 3 cSt to about 1,000 cSt.

6. The process according to claim 1 , wherein said PAO base stock is characterized by a KV 100 of greater than 3 cSt to about 700 cSt.

7. The process according to claim 4 , wherein said PAO base stock is characterized by a KV 100 of greater than 3 cSt to about 150 cSt and a TRB of 20 hrs of less than 3% viscosity change.

8. The process according to claim 4 , wherein said PAO base stock is characterized by a KV 100 of greater than 20 cSt to about 200 cSt and a TRB of 20 hrs of less than 2% viscosity change.

9. The process according to claim 4 , wherein said PAO base stock is characterized by a KV 100 of greater than 200 cSt to about 300 cSt and a TRB of 100 hrs of less than 4% viscosity change.

10. The process according to claim 1 , characterized by a product having a pour point lower than or equal to a product produced by the same reaction under the same conditions but without unreacted monomer recycle.

11. The process according to claim 1 , characterized by a product having a pour point lower than or equal to a product produced by the same reaction under the same conditions, including monomer recycle, but without purge of said monomer recycle.

12. The process according to claim 1 , characterized by a product having a pour point lower than or equal to a product produced by the same reaction under the same conditions but utilizing only fresh olefin feed.

13. The process according to claim 1 , characterized by a utilization of olefin feed of at least 50 wt %.

14. The process according to claim 1 , wherein said contacting occurs in the presence of H 2 .

15. The process according to claim 1 , wherein said contacting occurs in the absence of H 2 .

16. The process according to claim 1 , further comprising a step of obtaining a PAO product characterized by a Bromine number above 2 and hydrogenating said PAO product to obtain a hydrogenated product characterized by a Bromine number below 2.

17. The process according to claim 1 , wherein said feedstock to said contacting step comprises fresh olefin feed and recycled olefins, said recycled olefins comprising olefin monomers and olefin dimers, and wherein said olefin monomers of the recycled olefins comprise at least 20 wt % linear internal olefins, di-, and tri-substituted olefins.

18. The process according to claim 1 , wherein said process is a continuous, semi-batch or batch process.

19. The process according to claim 1 , wherein the recycled stream generated from the reactor effluent contains 5 to 40 wt % of the unreacted fresh feed olefin.

20. The process according to claim 1 wherein the polymerization temperature is reduced by 3° C. to 5° C.

Assignees

• Hagemeister Mark
• Kramer Anatoly Ilich
• Nandapurkar Pramod Jayant
• Wu Margaret May-Som
• Exxonmobil Chemical Patents Inc

Inventors

• Hagemeister Mark
• Kramer Anatoly Ilich
• Nandapurkar Pramod Jayant
• Tirmizi Shakeel
• Wu Margaret May-Som

Classifications

• C08F2500/17

  Viscosity · CPC title

• C08F210/14

  Monomers containing five or more carbon atoms · CPC title

• C08F110/14

  Monomers containing five or more carbon atoms · CPC title

• C08F4/65908

  in combination with an ionising compound other than alumoxane, e.g. (C6F5)4B-X+ · CPC title

• C08F10/00

  Homopolymers and copolymers of unsaturated aliphatic hydrocarbons having only one carbon-to-carbon double bond · CPC title