Catalyst – solid sorbent – or support therefor: product or process – Catalyst or precursor therefor – Plural component system comprising a - group i to iv metal...
Reexamination Certificate
2000-10-13
2004-01-06
Bell, Mark L. (Department: 1755)
Catalyst, solid sorbent, or support therefor: product or process
Catalyst or precursor therefor
Plural component system comprising a - group i to iv metal...
Reexamination Certificate
active
06673735
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to a method useful for forming derivatives of Group 3-10 metal compounds that are useful as catalysts and that are particularly adapted for use in the coordination polymerization of unsaturated compounds with improved efficiency and performance. Such compounds are particularly advantageous for use in a polymerization process wherein at least one polymerizable monomer is contacted with the catalyst compound under polymerization conditions to form a polymeric product.
It is previously known in the art to activate Ziegler-Natta polymerization catalysts, particularly such catalysts comprising Group 3-10 metal complexes containing delocalized &pgr;-bonded ligand groups, by the use of an activator. Generally in the absence of such an activator compound, also referred to as a cocatalyst, little or no polymerization activity is observed. A class of suitable activators are aluminoxanes, or alkylaluminoxanes, which are generally believed to be oligomeric or polymeric alkylaluminoxy compounds, including cyclic oligomers. Generally such compounds contain, on average about 1.5 alkyl groups per aluminum atom, and are prepared by reaction of trialkylaluminum compounds or mixtures of compounds with water (Reddy et al,
Prog. Poly. Sci
., 1995, 20, 309-367). The resulting product is in fact a mixture of various substituted aluminum compounds including especially, trialklyaluminum compounds (resulting from incomplete reaction of the trialkylaluminum starting reagent or decomposition of the alumoxane). The amount of such free trialkylaluminum compound in the mixture generally varies from 1 to 50 percent by weight of the total product. Examples of alumoxanes include methylalumoxane (MAO) made by hydrolysis of trimethylaluminum as well as modified methylalumoxane (MMAO), made by hydrolysis of a mixture of trimethylaluminum and triisobutylaluminum. MMAO advantageously is more soluble in aliphatic solvents than is MAO.
A different type of activator compound is a Bronsted acid salt capable of transferring a proton to form a cationic derivative or other catalytically active derivative of such Group 3-10 metal complex. Preferred Bronsted acid salts are such compounds containing a cation/anion pair that is capable of rendering the Group 3-10 metal complex catalytically active. Suitable activators comprise fluorinated arylborate anions, most preferably, the tetrakis(pentafluorophenyl)borate anion. Additional suitable anions include sterically shielded diboron anions of the formula:
wherein:
S is hydrogen, alkyl, fluoroalkyl, aryl, or fluoroaryl, Ar
F
is fluoroaryl, and X
1
is either hydrogen or halide, disclosed in U.S. Pat. No. 5,447,895.
Examples of preferred charge separated (cation/anion pair) activators are protonated ammonium, sulfonium, or phosphonium salts capable of transferring a hydrogen ion, disclosed in U.S. Pat. No. 5,198,401, U.S. Pat. No. 5,132,380, U.S. Pat. No. 5,470,927, and U.S. Pat. No. 5,153,157, as well as oxidizing salts such as carbonium, ferrocenium and silyilium salts, disclosed in U.S. Pat. No. 5,350,723, U.S. Pat. No. 5,189,192 and U.S. Pat. No. 5,626,087.
Further suitable activators for the above metal complexes include strong Lewis acids including (trisperfluorophenyl)borane and tris(perfluorobiphenyl)borane. The former composition has been previously disclosed for the above stated end use in EP-A-520,732, and elsewhere, whereas the latter composition is disclosed in Marks, et al.,
J. Am. Chem. Soc
., 118, 12451-12452 (1996). Additional teachings of the foregoing activators may be found in Chen, et al,
J. Am. Chem. Soc
. 1997, 119, 2582-2583, Jia et al,
Organometallics
, 1997, 16, 842-857. and Coles et al,
J. Am. Chem. Soc
. 1997, 119, 8126-8126.
In U.S. Pat. No. 5,453,410, an alumoxane, particularly methylalumoxane, was disclosed for use in combination with constrained geometry, Group 4 metal complexes, especially in a molar ratio of metal complex to alumoxane of from 1/1 to 1/50. This combination beneficially resulted in improved polymerization efficiency. Similarly, in U.S. Pat. No. 5,527,929, U.S. Pat. No. 5,616,664, U.S. Pat. No. 5,470,993, U.S. Pat. No. 5,556,928, U.S. Pat. No. 5,624,878, various combinations of metal complexes with trispentafluorophenyl boron cocatalyst, and optionally an alumoxane, were disclosed for use as catalyst compositions for olefin polymerization.
It is known that an exchange reaction between aluminum trialkyl compounds and tris(perfluorophenyl)borane occurs under certain conditions. This phenomenon has been previously described in U.S. Pat. No. 5,602,269. Tris(perfluorophenyl)aluminum is a strong Lewis acid as well. However, it generally performs poorly by itself as an activator compared with tris(perfluorophenyl)borane. Similarly, it has further been demonstrated that active catalysts resulting from the use of an aluminate anion based upon tris(perfluorophenyl)aluminum for the activation of ansa-metallocenes and biscyclopentadienyl derivatives of zirconium(IV) are generally of lower activity than those formed by the corresponding borane (Ewen,
Stud. in Surf. Sci. Catal
. 1994, 89, 405-410). The foregoing tri(fluoroaryl)aluminum compounds are considered to be moderately shock and temperature sensitive and difficult to handle in the pure state. In order to avoid this problem, the compounds may be prepared as adducts with Lewis bases such as ethers and/or retained in relatively dilute hydrocarbon solution. Disadvantageously, however, the presence of an ether in the catalyst composition detrimentally affects the ability to use the compounds as activators for metal complexes, and shipment of the activator compound in dilute solution adds to catalyst costs.
SUMMARY OF THE INVENTION
According to the present invention there is now provided a process for forming a composition useful as a catalyst for the polymerization of addition polymerizable monomers, the steps of the process comprising:
a) contacting under exchange reaction conditions a tri(hydrocarbyl)aluminum compound with a tri(fluoroaryl)boron compound; and
b) contacting the reaction product from step a) without recovery or isolation thereof, with a neutral Group 3-10 metal complex.
Additionally, there is provided a process for polymerization of one or more addition polymerizable monomers comprising contacting the same, optionally in the presence of an inert aliphatic, alicyclic or aromatic hydrocarbon, with the catalyst composition prepared by the foregoing process, or a supported derivative thereof.
Desirably, the exchange reaction is conducted in a dilute hydrocarbon solution and the reaction product retained, to the extent it is retained, in relatively dilute concentration in such hydrocarbon solvent. Effectively, the process uses the Group 3-10 metal complex as a base to react with the fluoroarylaluminum specie formed in the exchange reaction, thereby driving the reaction to completion and avoiding formation or recovery of a shock sensitive composition. Further desirably, the resulting composition is added to a polymerization reactor simultaneously with formation of the active catalyst composition or shortly thereafter, thereby avoiding storage or handling of the resulting complex in pure or concentrated form. In a most preferred embodiment, the foregoing process is conducted continuously, and the catalytically active product is continuously injected into a polymerization reactor substantially concurrently as it is formed or shortly thereafter. In a particular embodiment the catalytically active product is not stored in a separate container from the reactor in which it is formed prior to use as a polymerization catalyst. The process allows for the use of highly active aluminum Lewis acid catalyst activators in high efficiency while avoiding the need for their recovery, storage or transport or the storage or transport of the sensitive fluoroarylalumium Lewis acid compound.
Desirably, the metal complex contains one or more ligand groups able to form a partially or fully charge separated cationic or polycationic metal comp
Chen Eugene Y.
Kruper, Jr. William J.
Bell Mark L.
Brown Jennine
Dow Global Technologies Inc.
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