Oligomerization Of Alpha Olefins Using Metallocene-Ssa Catalyst Systems And Use Of The Resultant Polyalphaolefins To Prepare Lubricant Blends

CATEGORY: OLEFINS
PATENT
Oligomerization Of Alpha Olefins Using Metallocene-Ssa Catalyst Systems And Use Of The Resultant Polyalphaolefins To Prepare Lubricant Blends
European Patent Application EP2443160
Inventors:
Small, Brooke L. (3135 Beaver Glen Drive, Kingwood TX 77339, US)
Hope, Kenneth D. (3711 Scenic Valley Drive, Kingwood TX 77345, US)
Masino, Albert P. (8628 S. Oswego Avenue, Tulsa OK 74137, US)
Mcdaniel, Max P. (1601 Melmart Drive, Bartlesville OK 74006, US)
Buck, Richard M. (4319 Fairview Road, Bartlesville OK 74006, US)
Beaulieu, William B. (1209 Willow Park Drive, Bartlesville OK 74006, US)
Yang, Qing (2917 Montrose Drive, Bartlesville OK 74006, US)
Baralt, Eduardo J. (3822 Wildwood Valley Court, Kingwood TX 77345, US)
Netemeyer, Eric J. (1904 Barnett Court, Bartlesville OK 74006, US)
Kreischer, Bruce (20443 Crimson Oak Trail, Kingwood TX 77345, US)
Application Number:
EP20100728501
Publication Date:
04/25/2012
Assignee:
Chevron Phillips Chemical Company LP (10001 Six Pines Drive, The Woodlands, Texas 77380, US)
TECHNICAL FIELD OF THE INVENTION
This disclosure relates to the metallocene catalyzed oligomerization of alpha olefins to form alpha olefin oligomers and their hydrogenation to polyalphaolefins which have utility in synthetic lubricants and viscosity modifiers.
BACKGROUND OF THE INVENTION
[003] Mono- 1 -olefins (alpha olefins), including ethylene, can be polymerized with catalyst systems employing titanium, zirconium, vanadium, chromium or other metals impregnated on a variety of support materials, often in the presence of activators. These catalyst systems can be useful for both the homopolymerization of ethylene and copolymerization of ethylene with comonomers such as propylene, 1-butene, 1-hexene, or higher alpha olefins. Because of the importance in this process for preparing functional materials, there exists a need and a constant search to develop new olefin polymerization catalysts, catalyst activation processes, and methods of making and using catalysts that will provide enhanced catalytic activities, selectivities, or new polymeric materials tailored to specific end uses.
[004] One type of transition metal-based catalyst system utilizes metallocene compounds, often contacted with an activator such as methyl aluminoxane (MAO) to form an oligomerization catalyst. However, in order to achieve the desired high oligomerization activities, large amounts of expensive methyl aluminoxane typically are necessary to form the active metallocene catalysts. This feature has been an impediment to the commercialization of metallocene catalyst systems. Therefore improvements in catalyst systems and in methods of making the catalyst are needed to afford the desired oligomerization activities at reasonable commercial costs. Moreover, there remain important challenges in developing catalysts that can provide polymers or oligomers with the desired properties that can be tailored or maintained within a desired specification range. SUMMARY OF THE INVENTION
[005] This disclosure provides for alpha olefin oligomers, hydrogenated alpha olefin oligomers (also termed polyalphaolefms or PAOs throughout this disclosure), methods of making the alpha olefin oligomers, method of making hydrogenated alpha olefin oligomers, catalyst systems, and methods for preparing catalyst systems. In particular, this disclosure provides for alpha olefin homooligomers (or homopolymers), hydrogenated alpha olefin homooligomers, alpha olefin cooligomers (or copolymers), or hydrogenated alpha olefin cooligomers in which the alpha olefin monomers do not include ethylene. In the course of examining metallocene-based olefin polymerization catalysts, it was discovered that oligomerization of higher alpha olefins (C3 and higher) could be effected using metallocenes and related catalyst components, in which the metallocenes can be employed along with an activator comprising a solid oxide chemically-treated with an electron withdrawing anion.
[006] Alpha olefin oligomerization can be achieved by contacting an alpha olefin and a catalyst system, in which the catalyst system is a metallocene-based system. In an aspect, the catalyst system comprises a metallocene and an activator. In an aspect, the activator comprises a solid oxide chemically-treated with an electron withdrawing anion. In one aspect, the activator can be an aluminoxane (e.g. methyl aluminoxane (MAO) or modified methyl aluminoxane (MMAO)). In a further aspect, the resulting hydrogenated alpha olefin oligomers can be characterized as having a high viscosity index; alternatively, having a high viscosity index and a low pour point. Such features afford particular utility of these PAOs in lubricant compositions. Moreover, the methods disclosed herein provide for a process to adjust a viscosity or to select a desired viscosity range by regulating certain oligomerization or processing parameters. Yet another aspect of this disclosure provides for a PAO comprising monomer units derived from alpha olefins in which the alpha olefin monomers do not substantially include 1-decene. It has been discovered that the PAO comprising monomer units derived from alpha olefins which do not substantially include 1 -decene do not have to be blended with a PAO comprising monomer units based upon 1 -decene to afford PAOs having a high viscosity index and a low pour point. The first-pass economic advantages of this process for providing lubricant compositions are apparent.
[007] According to an aspect of this disclosure, there is provided an oligomerization method, the method comprising: a) contacting an alpha olefin monomer and a catalyst system, the catalyst system comprising at least one metallocene and a chemically-treated solid oxide; and b) forming an oligomer product under oligomerization conditions. According to one aspect of this disclosure, there is provided an oligomerization method, the method comprising: a) contacting an alpha olefin monomer and a catalyst system, the catalyst system comprising 1) at least one metallocene;
2) at least one first activator comprising a chemically-treated solid oxide; and
3) at least one second activator; and b) forming an oligomer product under oligomerization conditions.
In an embodiment, the chemically -treated solid oxide can be a fluorided silica-alumina. In an embodiment, the second activator can comprise organoaluminum compound. Further, the alpha olefin monomer and catalyst system can be contacted by the steps of simultaneously contacting the alpha olefin monomer, the metallocene, the first activator, and the second activator. Alternatively, the alpha olefin monomer and catalyst system can be contacted in any order, without limitation.
[008] In one aspect, this disclosure provides for a polyalphaolefin having a 100 0C kinematic viscosity from 20 cSt to 1,200 cSt. In another aspect, this disclosure provides for a polyalphaolefin having a pour point less than -20 0C. In some embodiments, this disclosure provides for a polyalphaolefin having a 100 0C kinematic viscosity from 20 cSt to 270 cSt and a pour point less than -30 0C. Other useful properties such as Mw molecular weight, Mn molecular weight, polydispersity index, shear stability, crystallization properties, tacticity, and Bernoulli index (B) are described. In an aspect, the PAOs disclosed herein can comprise primarily head-to- tail oligomers. In an embodiment, the PAO disclosed herein can comprise head-to-tail oligomers in which there are less than 100 errors per 1000 alpha olefin monomers.
[009] In an aspect, the alpha olefin monomer can comprise, singly or in any combination, a C3 to C70 normal alpha olefin; alternatively, a C4 to C20 normal alpha olefins. In an embodiment, the alpha olefin monomer can comprise 1-hexene, 1-octene, 1-decene, 1-dodecene, 1 -tetradecene, or any combination thereof.
[0010] A lubricant composition comprising a polyalphaolefin composition prepared according to this disclosure is also provided. The lubricant composition can consist essentially of the PAO composition with or without additives, such as metal deactivators, detergents, dispersants, antioxidants, and the like.
[0011] This disclosure further provides for a method of producing a polyalphaolefin, the method comprising: a) contacting an alpha olefin monomer and a catalyst system comprising a metallocene; and b) forming an oligomer product under oligomerization conditions. The method of producing the polyalphaolefin can further comprise separating a reactor effluent to produce a heavy oligomer product and hydrogenating the heavy oligomer product to produce the polyalphaolefin. The catalyst system can further include an activator or a combination of activators; alternatively, the catalyst system can be substantially devoid of an activator. In some embodiments, the catalyst system can further comprise an activator. In some embodiments, the activator can be an alumoxane (for example methyl alumoxane or a modified methyl alumoxane), a trialkylaluminum compound, an alkylaluminum hydride compound, an alkylaluminum halide compound, an organozinc compound, an organomagnesium compound, an organolithium compound, an organoboron compound, an ionizing ionic compound, a borate compound, or an aluminate compound, or any combination thereof.
[0012] In one aspect, the activator can comprise a solid oxide chemically-treated with an electron withdrawing anion. In some embodiments, the solid oxide chemically-treated with an electron withdrawing anion can include fluorided alumina, chlorided alumina, sulfated alumina, fluorided silica-alumina, chlorided silica-alumina, fluorided silica-zirconia, or combinations thereof. Therefore, this disclosure encompasses a method of producing a polyalphaolefin, comprising: a) contacting an alpha olefin and a catalyst system comprising: a metallocene; and an activator comprising a solid oxide chemically-treated with an electron withdrawing anion; and b) forming an oligomer product under oligomerization conditions.
When a solid oxide chemically-treated with an electron withdrawing anion is employed as an activator, it can be used alone or in combination with additional activators. Examples of activators that can be used in combination with a chemically-treated solid oxide include, but are not limited to, an alumoxane (e.g. methyl alumoxane or a modified methyl alumoxane), a trialkylaluminum compound, an alkylaluminum hydride compound, an alkylaluminum halide compound, an organozinc compound, an organomagnesium compound, an organolithium compound, an organoboron compound, an ionizing ionic compound, a borate compound, or an aluminate compound, or any combination thereof.
[0013] A further aspect of this disclosure provides a method of producing an oligomer product, which can be further processed to a polyalphaolefin, in which any combination of alpha olefin monomer, metallocene, solid oxide, electron withdrawing anion, or any other any activator can be precontacted prior to their use in the catalytic process. In this aspect, any precontacting step or steps can be carried out for any length of time prior to the step of contacting the alpha olefin to be oligomerized and the catalyst system to initiate the alpha olefin oligomerization. [0014] A wide range of metallocene compounds are suitable for use in the methods disclosed herein. The term "metallocene" is defined herein and is generally intended to include compounds that contain at least one pi-bonded ηx≥ 5 ligand. Generally, the pi-bonded ηx≥ 5 ligand can be a η5- cyclopentadienyl, η5-indenyl, η5-fluorenyl, η5-alkadienyl-, or η6-boratabenzene-ligands. Pi- bonded ηx≥ 5 ligands are also referred to as Group I ligands in this disclosure. Therefore, compounds that include only a single pi-bonded ηx≥ 5 ligand are encompassed by the term "metallocene" as used in this disclosure. In an aspect, the metal of the metallocenes can comprise a Group 4, 5, or 6 metal. Suitable metallocenes can comprise a metal selected from titanium, zirconium, hafnium, vanadium, niobium, tantalum, chromium, molybdenum, or tungsten. Any substituent or substituents on the pi-bonded ηx≥ 5 ligand that does not completely eliminate the activity of the resulting catalyst system is encompassed by this disclosure. Metallocenes of this disclosure can also contain Group II ligands that are exclusive of pi-bonded ηx≥ 5 ligands. The non pi-bonded ηx≥ 5 ligands can include formally monoanionic ligands that occupy a single coordinate site on the metal. These monoanionic ligands can include halides, hydrides, hydrocarbyl ligands, hydrocarboxy ligands, and aminyl ligands.
[0015] Suitable metallocenes include those that comprise multiple ligands. In some embodiments, the ligands of a metallocene containing multiple ligands can be unbridged; alternatively, the ligands of a metallocene containing multiple ligands can be connected by a linking group. For example, suitable metallocene compounds for use in the catalyst systems include metallocenes in which the metallocene contains two Group I ligands (pi-bonded ηx≥ 5 ligands) that are connected by a linking group. Other suitable metallocenes include those in which a Group I ligand (pi-bonded ηx≥ 5 ligand) can be connected by a linking group to a Group II ligand.
[0016] This disclosure also provides new catalyst systems for preparing an oligomer product (which can be further processed into polyalphaolefins), new methods for preparing catalyst systems, and methods for oligomerizing alpha olefins that result in improved productivity, without the need for using large excess concentrations of expensive activators such as methylaluminoxanes or modified methylaluminoxanes.
[0017] Additionally, this disclosure encompasses a process comprising contacting at least one monomer and the postcontacted catalyst system under oligomerization conditions to produce the oligomer. Thus, this disclosure provides methods for oligomerizing olefins using the catalyst systems prepared as described herein. [0018] These and other embodiments and aspects of the alpha olefin oligomers and of the oligomerization process are described more fully in the Detailed Description and claims and further disclosure provided herein.
BRIEF DESCRIPTION OF THE FIGURES [0019] FIG. 1 provides a plot of the scanning Brookfield dynamic viscosity (cP) versus temperature (0C) of a polyalphaolefin blend of hydrogenated 1-octene oligomers according to this disclosure, having a 1000C kinematic viscosity of 38.8 cSt, compared to a commercially available PAO produced from 1-decene having nearly the same kinematic viscosity (PAO 40). Sample identification: A, Blend B-2, blend of hydrogenated 1-octene oligomers having a 100 0C kinematic viscosity of 38.8 cSt; B, commercially available PAO 40. Refer to Tables 6 and 7 for sample preparation and properties.
[0020] FIG. 2 provides a plot of the scanning Brookfield dynamic viscosity (cP) versus temperature (0C) of a polyalphaolefin blend of hydrogenated 1-octene oligomers having a 1000C kinematic viscosity of 99.3 cSt, compared to a commercially available PAO produced from 1- decene having nearly the same kinematic viscosity (PAO 100). Sample identification: A, Blend B-3, blend of hydrogenated 1-octene oligomers having 100 0C kinematic viscosity of 100 cSt; B, commercially available PAO 100. Refer to Tables 6 and 7 for sample preparation and properties.
[0021] FIG. 3 provides the results of an RPVOT (Rotary Pressure Vessel Oxidation Test) analysis of the oxidation stability of the hydrogenated 1-octene oligomers, measured according to ASTM D2272. The oxidative stability plot of oxygen pressure (psig) versus time (minutes) to illustrate the comparative oxidative stability of hydrogenated 1-octene oligomers prepared using a metallocene and a chemically treated solid oxide catalyst system, as compared to commercial PAOs. Sample identification: A, Blend B-2, blend of hydrogenated 1-octene oligomers having a 100 0C kinematic viscosity of 38.8 cSt; B, hydrogenated 1-octene oligomers having a 100 0C kinematic viscosity of 121 cSt (oligomers hydrogenated at 210 0C); C, hydrogenated 1-octene oligomers having a 100 0C kinematic viscosity of 12IcSt (oligomers hydrogenated at 165 0C); D, commercially available PAO 40 produced from 1 -decene; E, commercially available PAO 100 produced from 1-decene. Refer to Tables 6 and 7 for sample preparation and properties.
[0022] FIG. 4 illustrates the effect of the metallocene of the oligomerization catalyst system on the 100 0C kinematic viscosity of hydrogenated oligomers produced using the oligomerization catalyst system and procedures described herein. FIG. 4 plots the dynamic viscosity (cP) versus temperature (0C) of a series of hydrogenated oligomers produced using different metallocene oligomerization catalyst systems and a commercially available polyalphaolefins having a kinematic viscosity of 40 cSt at 1000C. Sample identification: A, hydrogenated 1-decene oligomers having a 100 0C kinematic viscosity of 4IcSt prepared using metallocene J (Example 8 - Run 5); B, hydrogenated 1-octene oligomers having a 100 0C kinematic viscosity of 43.8 cSt prepared using metallocene N (Example 8 - Run 6); C, hydrogenated 1-octene oligomers having a 100 0C kinematic viscosity of 37 cSt prepared using metallocene L (Example 8 - Run 7) ; D, commercially available PAO 40; E, Blend B-2, blend of hydrogenated 1-octene oligomers having a 100 0C kinematic viscosity of 38.8 cSt. Refer to Tables 6 and 7 for sample preparation and properties.
[0023] FIG. 5 illustrates the effect of metallocene of the oligomerization catalyst system on the 100 0C kinematic viscosity of hydrogenated oligomers produced using the oligomerization catalyst system and procedures described herein. FIG. 5 plots the dynamic viscosity (cP) versus temperature (0C) of a series of hydrogenated oligomers produced using different metallocene oligomerization catalyst systems and commercially available polyalphaolefin having a kinematic viscosity of 100 cSt at 1000C. Sample identification: A, hydrogenated 1-octene oligomers having a 100 0C kinematic viscosity of 118 cSt prepared using metallocene J (Example 8 - Run 10); B, hydrogenated 1-decene oligomers having a 100 0C kinematic viscosity of 100.5 cSt prepared using metallocene J (Example 8 - Run 11); C, hydrogenated 1-octene oligomers having a 112.7 0C kinematic viscosity of 43.8 cSt prepared using metallocene B (Example 8 - Run 12); D, commercially available PAO 100. Refer to Tables 6 and 7 for sample preparation and properties. [0024] FIG. 6 provides a DSC of PAO produced using 1-octene according to Experiment 8 - Run 6. The DSC indicates that there is no discernable crystallization according to the DSC method described herein.
[0025] FIG. 7 provides a DSC of PAO produced using 1-decene according to Experiment 8 - Run 5. The DSC indicates that there is no discernable crystallization according to the DSC method described herein.
[0026] FIG. 8 provides a DSC of PAO produced using 1-octene according to Experiment 8 - Run 10. The DSC indicates that there is no discernable crystallization according to the DSC method described herein.
[0027] FIG. 9 provides a DSC of PAO produced using 1-decene according to Experiment 8 - Run 11. The DSC indicates that there is a small discernable crystallization according to the DSC method described herein. [0028] FIG. 10 provides a DSC of PAO produced using 1-octene according to Experiment 8 - Run 12. The DSC indicates that there is no discernable crystallization according to the DSC method described herein.
[0029] FIG. 12 provides a DSC of a commercial PAO 100. The DSC indicates that there is a discernable crystallization according to the DSC method described herein.
DETAILED DESCRIPTION OF THE INVENTION
General Description
[0030] This disclosure provides for oligomers derived from alpha olefin (also referred to as alpha olefin oligomers), hydrogenated oligomer (also described throughout as polyalphaolefms or PAOs), methods of making the alpha olefin oligomers, methods for making PAOs, catalyst systems, and methods making catalyst systems. In particular, this disclosure encompasses oligomerizing one or more alpha olefins using a catalyst system that comprises a metallocene. The catalyst system can further comprise one or more activators. One type of activator that can be particularly useful is a solid oxide that has been chemically-treated with an electron withdrawing anion, which is fully described herein. The solid oxide that has been chemically -treated with an electron withdrawing anion can also be referred to throughout this disclosure as a chemically treated solid oxide (CTSO), a solid super acid (SSA), or an activator-support, and these terms are used interchangeably. Other activators can be used with the metallocenes in the catalyst system, either alone, in combination with the SSA, or in any combination with at least one other activator. Thus, by way of example, the catalyst system can comprise at least one metallocene, a first activator, and a second activator. In an aspect, the first activator can comprise, consist essentially of, or consist of, a chemically-treated solid oxide and the second activator can comprise, consist essentially of, or consist of, an organoaluminum compound. In a non-limiting embodiment, the chemically-treated solid oxide can be fluorided silica-alumina, and the second activator can be a trialkylaluminum compound (e.g. triethyl aluminum and/or triisobutyl aluminum).
[0031] These metallocene-based alpha olefin oligomerizations provide olefin oligomers and ultimately polyalphaolefms with particularly useful properties. The metallocene-based alpha olefin oligomerizations allow for variability in the properties of the oligomers and PAOs on the basis of the catalyst system and/or oligomerization conditions, among other factors described herein. For example, certain properties of the 1-octene homooligomers prepared according to this disclosure, and PAOs produced by hydrogenation the homooligomers, can be selected by adjusting the temperature at which the oligomerization is carried out. Moreover, this control extends to controlling product viscosity and pour point such that high value PAOs having 1000C kinematic viscosities of 100 cSt and/or 40 cSt can be prepared.
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