Low viscosity poly-alpha-olefins

Patent metadata

Field	Value
Publication number	US-9409834-B2
Application number	US-201213476686-A
Country	US
Kind code	B2
Filing date	May 21, 2012
Priority date	Jul 19, 2005
Publication date	Aug 9, 2016
Grant date	Aug 9, 2016

Abstract

A low viscosity poly(apha-olefin) (PAO) is produced by contacting one or more C3 to C24 alpha-olefins with an unbridged, substituted bis cyclopentadienyl transition metal compound, a non-coordinating anion activator, and an alkyl-aluminum compound. The molar ratio of transition metal compound to activator is 10:1 to 0.1:1, and the molar ratio of alkyl aluminum compound to transition metal compound is 1:4 to 4000:1. The transition metal compound has either (a) at least one non-isoolefin substitution on both cyclopentadienyl rings, or (b) at least two substitutions on at least one cyclopentadienyl ring. The PAO is comprised of at least 50 mole % of C3 to C24 alpha-olefins and has a kinematic viscosity at 100° C. of 20 cSt or less.

First claim

The invention claimed is:

1. A polyalpha-olefin having a kinematic viscosity at 100° C. of less than 12 cSt, a Mw/Mn of between 1 and 1.4, a selectivity of 35 wt % or less for C20 and lower olefins, a pour point of −60° C. or less, and a viscosity index of 156 or greater.

2. The polyalpha-olefin of claim 1 wherein the polyalpha-olefin has a kinematic viscosity at 100° C. of 10 cSt or less.

3. The polyalpha-olefin of claim 1 wherein the polyalpha-olefin is polydecene.

4. The polyalpha-olefin of claim 1 wherein the polyalpha-olefin has a Bromine number of 1.8 or more.

5. The polyalpha-olefin of claim 1 wherein the polyalpha-olefin has a weight average molecular weight of 100 to 50,000 g/mol.

6. The polyalpha-olefin of claim 1 wherein the polyalpha-olefin is comprised of 30 wt % or less C10 dimer.

7. A process to produce the polyalpha-olefin of claim 1 comprising:
contacting one or more alpha-olefin monomers having 3 to 24 carbon atoms with 1) a transition metal compound, wherein the compound is a) an unbridged, mono-substituted bis cyclopentadienyl transition metal compound, wherein the substitution is a non-isoolefin substitution on both cyclopentadienyl rings or b) an unbridged substituted bis cyclopentadienyl transition metal compound having at least two substitutions on at least one cyclopentadienyl ring; 2) a non-coordinating anion activator; and 3) an alkyl-aluminum compound, where the molar ratio of transition metal compound to activator is 2:1 to 0.5:1, the molar ratio of alkyl aluminum compound to transition metal compound is 2:1 to 500:1, and the milligram amount of transition metal compound per gram of alpha-olefin monomer is in the range of 0.001 to 1, under polymerization conditions wherein:
i) hydrogen is present at a partial pressure of 0.1 psi to less than 50 psi, based upon the total pressure of the reactor;
ii) wherein the alpha-olefin monomer(s) having 3 to 24 carbon atoms are present at 10 volume % or more based upon the total volume of the catalyst/activator/alkylaluminum compound solutions, monomers, and any diluents or solvents present in the reaction;
iii) the residence time of the reaction is at least 5 minutes;
iv) the productivity of the process is at least 43,000 grams of total product per gram of transition metal compound;
v) the process is continuous or semi-continuous; and
vi) ethylene is not present at more than 30 volume % of the monomers entering the reaction zone.

8. The process of claim 7 wherein the alpha-olefin monomers are selected from the group consisting of 1-pentene, 1-hexene, 1-heptene, 1-octene, 1-nonene, 1-decene, 1-undecene, 1-dodecene, 1-tridecene, 1-tetradecene, 1-pentadecene, and 1-hexadecene.

9. The process of claim 7 wherein the polyalpha-olefin has been contacted with a hydrogenation catalyst to form a treated polyalpha-olefin and the polyalpha-olefin has a bromine number less than 1.8.

10. The process of claim 9 wherein the treated polyalpha-olefin comprises 10 ppm of heteroatom containing compounds or less.

11. The process of claim 7 wherein the activator comprises one or more of N,N-dimethylanilinium tetra(pentafluorophenyl)borate, N,N-dialkylphenylanilinium tetra(pentafluorophenyl)borate (where the alkyl is a C1 to C18 alkyl group), trityl tetra(pentafluorophenyl)borate, tris(pentafluorophenyl)boron, tri-alkylammonium tetra(pentafluorophenyl)borate (where the alkyl is a C1 to C18 alkyl group), tetra-alkylammonium tetra(pentafluorophenyl)borate (where the alkyl is a C1 to C18 alkyl group).

12. The process of claim 7 wherein the transition metal compound comprises one or more of:
bis(methylcyclopentadienyl)hafnium dimethyl,
bis(methylcyclopentadienyl)zirconium dimethyl,
bis(ethylcyclopentadienyl)zirconium dimethyl,
bis(n-butylcyclopentadienyl)zirconium dimethyl,
bis(n-propylcyclopentadienyl)hafnium dimethyl, or
bis(n-propylcyclopentadienyl)zirconium dimethyl.

13. The process of claim 7 wherein the alkylaluminum compound is represented by the formula: R 3 Al, where each R is, independently, selected from the group consisting of methyl, ethyl, n-propyl, iso-propyl, iso-butyl, n-butyl, t-butyl, n-pentyl, iso-pentyl, neopentyl, n-hexyl, iso-hexyl, n-heptyl, iso-heptyl, n-octyl, iso-octyl, n-nonyl, n-decyl, n-undecyl, n-dodecyl, n-tridecyl, n-tetradecyl, n-pentadecyl, n-hexadecyl, n-heptadecyl, n-octadecyl, and their iso-analogs.

14. The process of claim 7 wherein during the contacting a concentration of hydrogen of 10,000 ppm or less by weight is maintained in the reactor.

15. The process of claim 7 wherein the monomers are contacted with an alkylaluminum compound prior to being introduced into the reactor.

16. The process of claim 7 wherein the transition metal compound and/or activator are combined with an alkylaluminum compound prior to entering the reactor.

Assignees

• Wu Margaret May-Som
• Coker Catalina L
• Walzer Jr John F
• Jiang Peijun
• Exxonmobil Chemical Patents Inc

Inventors

• Wu Margaret May-Som
• Coker Catalina L
• Walzer Jr John F
• Jiang Peijun

Classifications

• C10N2020/011

  Cloud point · CPC title

• C10N2020/065

  Saturated Compounds · CPC title

• C10N2020/013

  Iodine value · CPC title

• C10N2020/04

  Molecular weight; Molecular weight distribution · CPC title

• C10N2020/019

  Shear stability · CPC title