Patent Application
20130023635
The invention relates to non-metallocene catalyst systems useful for polymerizing olefins. The catalyst systems incorporate a tridentate dianionic ligand.
While Ziegler-Natta catalysts are a mainstay for polyolefin manufacture, single-site (metallocene and non-metallocene) catalysts represent the industry's future. These catalysts are often more reactive than Ziegler-Natta catalysts, and they produce polymers with improved physical properties. The improved properties include controlled molecular weight distribution, reduced low molecular weight extractables, enhanced incorporation of □-olefin comonomers, lower polymer density, controlled content and distribution of long-chain branching, and modified melt rheology and relaxation characteristics.
Traditional metallocenes incorporate one or more cyclopentadienyl (Cp) or Cp-like anionic ligands such as indenyl, fluorenyl, or the like, that donate pi-electrons to the transition metal. Non-metallocene single-site catalysts, including ones that capitalize on the chelate effect, have evolved more recently. Examples are the bidentate 8-quinolinoxy or 2-pyridinoxy complexes of Nagy et al. (see U.S. Pat. No. 5,637,660), the late transition metal bisimines of Brookhart et al. (see Chem. Rev. 100 (2000) 1169), and the diethylenetriamine-based tridentate complexes of McConville et al. or Shrock et al. (e.g., U.S. Pat. Nos. 5,889,128 and 6,271,323).
In numerous recent examples, the bi- or tridentate complex incorporates a pyridyl ligand that bears a heteroatom β- or γ- to the 2-position of the pyridine ring. This heteroatom, typically nitrogen or oxygen, and the pyridyl nitrogen chelate the metal to form a five- or six-membered ring. For some examples, see U.S. Pat. Nos. 7,439,205; 7,423,101; 7,157,400; 6,653,417; and 6,103,657 and U.S. Pat. Appl. Publ. No. 2008/0177020. In some of these complexes, an aryl substituent at the 6-position of the pyridine ring is also available to interact with the metal through C—H activation to form a tridentate complex (see, e.g., U.S. Pat. Nos. 7,115,689; 6,953,764; 6,706,829). Unfortunately, some of these complexes are tricky to prepare, and they are most useful unsupported; our own attempts to prepare similar complexes and support them on silica, for example, met with mixed results.
Less frequently, quinoline-based bi- or tridentate complexes have been described (see, e.g., U.S. Pat. Nos. 7,253,133; 7,049,378; 6,939,969; 6,103,657; 5,637,660 and Organometallics 16 (1997) 3282). The quinoline complexes disclosed in the art lack an 8-anilino substituent, a 2-aryl substituent, or both, and/or they are not dianionic and tridentate.
WO 2011/011041 describes catalyst systems based on 2-aryl-8-anilinquinoline ligands, however this document does not suggest that the aryl substituent can be replaced with an heterocyclic radical.
New non-metallocene catalyst system useful for making polyolefins continue to be of interest. In particular, tridentate complexes that can be readily synthesized from inexpensive reagents are needed. The complexes should not be useful only in homogeneous environments; a practical complex can be supported on silica and readily activated toward olefin polymerization with alumoxanes or boron-containing cocatalysts. Ideally, the catalysts have the potential to make ethylene copolymers having high or very high molecular weights and can be utilized in high-temperature solution polymerizations.
The invention relates to catalyst system useful for polymerizing olefins. The catalyst system comprises an activator and a Group 4 metal complex. The complex incorporates a dianionic, tridentate heterocyclic-8-anilinoquinoline ligand. In one aspect, a supported catalyst system is prepared by first combining a boron compound having Lewis acidity with excess alumoxane to produce an activator mixture, followed by combining the activator mixture with a support and the dianionic, tridentate Group 4 metal complex. The Group 4 metal complex are easy to synthesize, support, and activate, and they enable facile production of high-molecular-weight polyolefins.
The catalysts system of the invention comprises:
A) a Group 4 transition metal complex having formula (I)
B) one or more activators;
The catalyst system includes one or more activators. The activator helps to ionize the complex and activate the catalyst. Suitable activators are well known in the art. Examples include alumoxanes (methyl alumoxane (MAO), PMAO, ethyl alumoxane, diisobutyl alumoxane), alkylaluminum compounds (triethylaluminum, diethylaluminum chloride, trimethylaluminum, triisobutylaluminum), and the like. Suitable activators include boron and aluminum compounds having Lewis acidity such as ionic borates or aluminates, organoboranes, organoboronic acids, organoborinic acids, and the like. Specific examples include lithium tetrakis(pentafluorophenyl)borate, lithium tetrakis(pentafluorophenyl)aluminate, anilinium tetrakis(pentafluorophenyl)-borate, trityl tetrakis(pentafluorophenyl)borate (“F20”), tris(pentafluorophenyl)-borane (“F15”), triphenylborane, tri-n-octylborane, bis(pentafluorophenyl)borinic acid, pentafluorophenylboronic acid, and the like. These and other suitable boron-containing activators are described in U.S. Pat. Nos. 5,153,157, 5,198,401, and 5,241,025, the teachings of which are incorporated herein by reference. Suitable activators also include aluminoboronates—reaction products of alkyl aluminum compounds and organoboronic acids—as described in U.S. Pat. Nos. 5,414,180 and 5,648,440, the teachings of which are incorporated herein by reference. Particularly preferred activators are alumoxanes, boron compounds having Lewis acidity, and mixtures thereof.
Preferably the compound of formula (I) have formulas (Ia) or (Ib)
Wherein M, X, R1, R2, R3, R4 and R5 have been described above;
R7 and R8, equal to or different from each other, are C1-C40 hydrocarbon groups optionally containing one or more heteroatoms belonging to groups 13-17 of the Periodic Table of the Elements; preferably R7 and R8, equal to or different from each other, are linear or branched, cyclic or acyclic, C1-C40-alkyl, C2-C40 alkenyl, C2-C40 alkynyl, C6-C40-aryl, C7-C40-alkylaryl or C7-C40-arylalkyl radicals, optionally containing one or more heteroatoms belonging to groups 13-17 of the Periodic Table of the Elements; more preferably R7 and R8 are linear or branched C1-C10-alkyl radicals, such as methyl, ethyl, n-propyl, isopropyl, n-butyl, and tert-butyl;
R9 and R10, equal to or different from each other, are hydrogen atoms or C1-C40 hydrocarbon groups optionally containing one or more heteroatoms belonging to groups 13-17 of the Periodic Table of the Elements or R9 and R10 can be joined to form a C5-C6 membered ring; preferably a phenyl ring; preferably R9 and R10, equal to or different from each other, are linear or branched, cyclic or acyclic, C1-C40-alkyl, C2-C40 alkenyl, C2-C40 alkynyl, C6-C40-aryl, C7-C40-alkylaryl or C7-C40-arylalkyl radicals, optionally containing one or more heteroatoms belonging to groups 13-17 of the Periodic Table of the Elements or R9 and R10 can be joined to form a phenyl ring; preferably; even more preferably R10 is a C1-C10-alkyl radical or is joined with R9 to form a phenyl ring; even more preferably R9 is a hydrogen atom or is joined with R10 to form a phenyl ring. Z1 is S, O, or NR6 wherein R6 has been described above; preferably Z is S or NR6 wherein R6 is a C1-C10-alkyl or a C6-C20-aryl radical; more preferably R6 is a phenyl radical or a methyl, ethyl, n-propyl, isopropyl, n-butyl, and tert-butyl radical;
The catalyst system of the present invention can further comprise an inert support c). Preferably inert support are inorganic oxide such as silica, alumina, silica-alumina, magnesia, titania, zirconia, clays, zeolites, or the like. Silica is preferred. When silica is used, it preferably has a surface area in the range of 10 to 1000 m2/g, more preferably from 50 to 800 m2/g and most preferably from 200 to 700 m2/g. Preferably, the pore volume of the silica is in the range of 0.05 to 4.0 mL/g, more preferably from 0.08 to 3.5 mL/g, and most preferably from 0.1 to 3.0 mL/g. Preferably, the average particle size of the silica is in the range of 1 to 500 microns, more preferably from 2 to 200 microns, and most preferably from 2 to 45 microns. The average pore diameter is typically in the range of 5 to 1000 angstroms, preferably 10 to 500 angstroms, and most preferably 20 to 350 angstroms.
The support is preferably treated thermally, chemically, or both prior to use by methods well known in the art to reduce the concentration of surface hydroxyl groups. Thermal treatment consists of heating (or “calcining”) the support in a dry atmosphere at elevated temperature, preferably greater than 100° C., and more preferably from 150 to 800° C., prior to use. A variety of different chemical treatments can be used, including reaction with organo-aluminum, -magnesium, -silicon, or -boron compounds. See, for example, the techniques described in U.S. Pat. No. 6,211,311, the teachings of which are incorporated herein by reference.
Highly active non-metallocene catalysts of the invention can be made by using a particular sequence for activating and supporting the tridentate dianionic complexes. One method of preparing a supported catalyst useful for polymerizing olefins comprises two steps. In a first step, a boron compound having Lewis acidity (as described earlier) is combined with excess alumoxane, preferably methylalumoxane, to produce an activator mixture. In a second step, the resulting activator mixture is combined with a support, preferably silica, and a complex which comprises a Group 4 transition metal and a dianionic, tridentate 2-aryl-8-anilinoquinoline ligand. In one approach, the activator mixture is combined with the complex first, followed by the support. However, the order can be reversed; thus, the activator mixture can be combined with the support first, followed by the complex.
In a typical example, the boron compound is combined with excess MAO in a minimal amount of a hydrocarbon. The complex is added and the combined mixture is then added to a large proportion of calcined silica in an incipient wetness technique to provide the supported catalyst as a free-flowing powder.
A further object of the present invention is the organic ligand of formula (II)
Wherein Z, n, R1, R2, R3, R4, R5 and W have been described above.
Preferably the ligand of formula (II) has formula (IIa) or (IIb)
Wherein Z1, R1, R2, R3, R4, R5, R7, R8, R9 and R10 have been described above.
With the catalyst system of the present invention it is possible to polymerize alpha-olefins in high yield to obtain polymers having high molecular weight. Thus a further object of the present invention is a process for polymerizing one or more alpha olefins of formula CH2═CHT wherein T is hydrogen or a C1-C20 alkyl radical comprising the step of contacting said alpha-olefins of formula CH2═CHT under polymerization conditions in the presence of the catalyst system described above.
Preferred α-olefins are ethylene, propylene, 1-butene, 1-hexene, 1-octene.
The catalyst system of the present invention is particularly fit for the polymerization of ethylene or copolymerization of ethylene and propylene, 1-butene, 1-hexene and 1-octene. Thus a further object of the present invention is a process for polymerizing ethylene and optionally one or more alpha olefins selected from propylene, 1-butene, 1-hexene and 1-octene comprising the step of contacting ethylene and optionally said alpha-olefins under polymerization conditions in the presence of the catalyst system described above.
Many types of olefin polymerization processes can be used. Preferably, the process is practiced in the liquid phase, which can include slurry, solution, suspension, or bulk processes, or a combination of these. High-pressure fluid phase or gas phase techniques can also be used. In a preferred olefin polymerization process, a supported catalyst of the invention is used. The polymerizations can be performed over a wide temperature range, such as −30° C. to 280° C. A more preferred range is from 30° C. to 180° C.; most preferred is the range from 60° C. to 100° C. Olefin partial pressures normally range from 15 psig to 50,000 psig. More preferred is the range from 15 psig to 1000 psig.
The invention includes a high-temperature solution polymerization process. By “high-temperature,” we mean at a temperature normally used for solution polymerizations, i.e., preferably greater than 130° C., and most preferably within the range of 135° C. to 250° C.
The following examples merely illustrate the invention. Those skilled in the art will recognize many variations that are within the spirit of the invention and scope of the claims.
All intermediate compounds and complexes synthesized give satisfactory 1H NMR spectra consistent with the structures indicated.
To a solution of 2-methyl-4-bromothiphene (1.77 g, 10 mmol) in 20 ml of ether a BuLi solution in hexane (10 mmol) was added at −50° C. After stirring for 2 h at this temperature, a solution of ZnCl2 (0.68 g, 5 mmol) in 10 ml of THF was added, allowed to reach ambient temperature and continued the reaction for an additional 20 min. The catalytic system Pd(dba)2 (100 mg) and PPh3 (100 mg) was added to the resulting solution, followed in 5 minutes by 2,8-dibromoquinoline (2.87, 10 mmol). The reaction mixture was stirred overnight, treated with a 10% solution of NH4Cl, the organic phase separated, while the aqueous layer extracted with ether. The combined organic phases were dried over MgSO4, evaporated and the residue purified on a silica column using a benzene-hexane (1:4) eluent, resulting in 1.12 g of product (37%).
NMR 1H (CDCl3): 8.08 (d, 1H), 8.03 (d, 1H); 7.86 (s, 1H); 7.74 (d, 1H); 7.68 (br.s., 1H); 7.31 (t, 1H); 2.59 (s, 3H).
A mixture of the 8-bromo-2-(5-methyl-3-thienyl)quinoline (3.7 mmol), 2,6-diisopropylaniline (0.71 g, 4.0 mmol), sodium tert-butylate (0.5 g), Pd(dba)2 (40 mg) and (N-[2′-(dicyclohexylphosphino)[1,1′-biphenyl]-2-yl]-N,N-dimethylamine) (60 mg) in 8 ml of toluene reacted under argon at 105° C. for 12 h. After addition of water, the organic phase separated and the aqueous layer extracted with ether. The combined organic phases were dried over MgSO4, evaporated and the residue purified on a silica column using a petroleum ether-benzene (5:1) eluent, resulting in 0.8 g of product (54%).
NMR 1H (CDCl3): 8.14 (d, 1H); 7.80 (m, 2H); 7.75 (br.s., 1H); 7.61 (br.s., 1H); 7.34 (m, 4H); 7.24 (t, 1H); 7.09 (d, 1H); 6.33 (d, 1H); 3.30 (m, 2H); 2.62 (s, 3H); 1.27 (d, 6H); 1.19 (d, 6H).
Solution of tetrabenzylzirconium (0.87 g, 1.92 mmol) in toluene-hexane (1:1, 10 ml) was added at 0° C. to a solution of N-(2,6-diisopropylphenyl)-2-(5-methyl-3-thienyl)-8-quinolinamine (0.64 g, 1.60 mmol) in toluene-hexane (1:1, 15 ml). The mixture was allowed to warm to room temperature, stirred overnight, and evaporated. The residue was recrystallized from hexane with the yield of 0.65 g (60%).
NMR 1H(C6D6) □: 7.60 (d, 1H); 7.41-6.62 (groups of m, 17H); 6.27 (d, 1H); 3.44 (m, 2H); 2.53 (d, 2H); 2.33 (s, 3H); 1.65 (d, 2H); 1.23 (d, 6H); 1.01 (d, 6H).
To a solution of 2-methyl-5-bromothiphene (1.77 g, 10 mmol) in 20 ml of ether a BuLi solution in hexane (10 mmol) was added at −50° C. After stirring for 2 h at this temperature, a solution of ZnCl2 (0.68 g, 5 mmol) in 10 ml of THF was added, allowed to reach ambient temperature and continued the reaction for an additional 20 min. The catalytic system Pd(dba)2 (100 mg) and PPh3 (100 mg) was added to the resulting solution, followed in 5 minutes by 2,8-dibromoquinoline (2.87, 10 mmol). The reaction mixture was stirred overnight, treated with a 10% solution of NH4Cl, the organic phase separated, while the aqueous layer extracted with ether. The combined organic phases were dried over MgSO4, evaporated and the residue purified on a silica column using a benzene-hexane (1:4) eluent, resulting in 0.85 g of product (28%).
NMR 1H (CDCl3): 8.10 (d, 1H), 8.05 (d, 1H); 7.77 (d, 1H); 7.74 (d, 1H); 7.66 (d, 1H); 7.33 (t, 1H); 2.57 (s, 3H).
A mixture of the 8-bromo-2-(5-methyl-2-thienyl)quinoline (2.8 mmol), 2,6-diisopropylaniline (0.71 g, 4.0 mmol), sodium tert-butylate (0.5 g), Pd(dba)2 (40 mg) and (N-[2′-(dicyclohexylphosphino)[1,1′-biphenyl]-2-yl]-N,N-dimethylamine) (60 mg) in 8 ml of toluene reacted under argon at 105° C. for 12 h. After addition of water, the organic phase separated and the aqueous layer extracted with ether. The combined organic phases were dried over MgSO4, evaporated and the residue purified on a silica column using a petroleum ether-benzene (5:1) eluent, resulting in 0.8 g of product (54%).
NMR 1H (CDCl3): 8.13 (d, 1H); 7.77 (m, 2H); 7.72 (br.s., 1H); 7.58 (br.s., 1H); 7.31 (m, 4H); 7.21 (t, 1H); 7.06 (d, 1H); 6.29 (d, 1H); 3.27 (m, 2H); 2.59 (s, 3H); 1.24 (d, 6H); 1.16 (d, 6H).
Solution of tetrabenzylzirconium (0.37 g, 0.81 mmol) in toluene-hexane (1:1, 3 ml) was added at 0° C. to a solution of N-(2,6-diisopropylphenyl)-2-(5-methyl-2-thienyl)-8-quinolinamine (0.27 g, 0.67 mmol) in toluene-hexane (1:1, 7 ml). The mixture was allowed to warm to room temperature, stirred overnight, and evaporated. The residue was recrystallized from hexane. The yield 0.21 g (46%).
NMR 1H (C6D6) □: 7.58 (d, 1H); 7.28-6.47 (groups of m, 17H); 6.19 (d, 1H); 3.52 (m, 2H); 2.59 (d, 2H); 2.28 (s, 3H); 1.77 (d, 2H); 1.26 (d, 6H); 1.03 (d, 6H).
To a solution of N-phenylindole (3.86 g, 20 mmol) in 30 ml of THF a BuLi solution in hexane (20 mmol) was added at 0° C. After stirring for 2 h at ambient temperature the mixture was cooled again to 0° C. and a solution of ZnCl2 (1.36 g, 10 mmol) in 20 ml of THF was added, allowed to reach ambient temperature and continued the reaction for an additional 20 min. The catalytic system Pd(dba)2 (200 mg) and PPh3 (200 mg) was added to the resulting solution, followed in 5 minutes by 2,8-dibromoquinoline (4.9 g, 17 mmol). The reaction mixture was stirred overnight, treated with a 10% solution of NH4Cl, the organic phase separated, while the aqueous layer extracted with ether. The combined organic phases were dried over MgSO4, evaporated and the residue washed with ethanol, resulting in 3.6 g of product (45.5%).
NMR 1H (CDCl3): 7.99 (d, 1H); 7.93 (d, 1H); 7.79 (d, 1H); 7.65 (t, 2H); 7.47 (m, 2H), 7.42 (m, 4H); 7.28 (m, 4H).
A mixture of the 8-bromo-2-(1-phenyl-1H-indol-2-yl)quinoline (1.6 g, 4 mmol), 2,6-diisopropylaniline (0.71 g, 4.0 mmol), sodium tert-butylate (0.75 g), Pd(dba)2 (60 mg) and (N-[2′-(dicyclohexylphosphino)[1,1′-biphenyl]-2-yl]-N,N-dimethylamine) (90 mg) in 12 ml of toluene reacted under argon at 105° C. for 12 h. After addition of water, the organic phase separated and the aqueous layer extracted with ether. The combined organic phases were dried over MgSO4, evaporated and the residue was washed with ethanol, resulting in 1.5 g of product (85%).
NMR 1H (CDCl3): 8.07 (d, 1H); 7.94 (d 1H); 7.82 (m, 1H); 7.48 (d, 2H); 7.40 (m, 3H); 7.27 (m, 2H); 7.18 (m, 6H); 7.02 (d, 1H); 6.17 (br.s., 1H); 6.10 (d, 1H); 2.14 (s, 6H).
Solution of tetrabenzylzirconium (0.45 g, 0.99 mmol) in toluene-hexane (1:1, 10 ml) was added at −20° C. to a solution of N-(2,6-dimethylphenyl)-2-(1-phenyl-1H-indol-2-yl)-8-quinolinamine (0.31 g, 0.71 mmol) in toluene-hexane (1:1, 10 ml). The mixture was allowed to warm to room temperature, stirred overnight, and evaporated. The residue was recrystallized from hexane. The yield 0.22 g (44%). Yellow crystalline powder.
NMR 1H (C6D6) □: 8.30 (d, 1H); 7.35 (t, 1H); 7.21 (t, 1H); 7.19-6.63 (groups of m, 22H); 6.46 (d, 1H); 6.23 (d, 1H); 2.57 (d, 2H); 2.20 (d, 2H); 2.15 (s, 6H).
Trityl tetrakis(pentafluorophenyl)borate (“F20, 0.03 g”) is added to methylalumoxane (30 wt. % solution of MAO in toluene, 1.4 mL), and the mixture is stirred for 15 min. A specified amount of complex precursor indicated in table 1 is added to the MAO/borate solution, and the mixture stirs for an additional 15 min. The resulting product is slowly added to a stirred bed of silica (Davison 948, calcined at 600° C. for 6 h, 1.0 g). The resulting free-flowing powder is used in polymerization tests.
In a representative procedure a dry, 2-L stainless-steel autoclave is charged with isobutane (1.0 L), triisobutylaluminum (1 M solution in hexanes, 2 mL), 1-butene (100 mL) and, optionally, hydrogen, and the contents are heated to 70° C. and pressurized with ethylene (22.5 psi partial pressure). Polymerization is started by injecting the catalyst with a small quantity of isobutane. The temperature is maintained at 70° C., and ethylene is supplied on demand throughout the test. The reaction is terminated after an hour by cooling the reactor and venting its contents. The results of the polymerization tests are reported on table 1.
The catalyst system of the present invention shows a good activity in the copolymerization of ethylene
