Organic compounds -- part of the class 532-570 series – Organic compounds – Heavy metal containing
Patent
1997-01-20
1999-03-16
Nazario-Gonzalez, Porfirio
Organic compounds -- part of the class 532-570 series
Organic compounds
Heavy metal containing
556 11, 556 12, 556 43, 556 47, 556 1, 534 14, 534 15, 502103, 502117, 526160, 526943, C07F 1700, C07F 700, C07F 900
Patent
active
058832785
DESCRIPTION:
BRIEF SUMMARY
The invention relates generally to the preparation of metallocenes which are useful as stereoregular oiefin polymerization catalysts and more specifically to a process for metallizing cyclopentadienyl ligand salts with certain transition, lanthanide or actinide metal compounds which are chelate diamine adducts of the metal halides.
As known in the art, metallocenes can be prepared by reacting a metal compound of the formula MX.sub.n, where M is the metal, n is an integer of 1 to 6, depending upon the valence of M, and X is independently an anionic ligand group or a neutral Lewis base ligand group having up to 30 non-hydrogen atoms such as hydride, halo, alkyl, aryl, silyl, germyl, aryloxy, aikoxy, amide, and siloxy, with an alkali metal or a magnesium halide salt of a cyclopentadienyl ligand in a solvent such as an ether.
Chiral metallocenes are useful for the synthesis of polyolefins. Specifically, the racemic form of the metallocene provides stereoregular poly(alpha-olefins) in addition to being considerably more active than the meso form, which produces only atactic polymers. An efficient synthesis of chiral metallocenes that favors the formation of the racemic isomer at the metallation stage is desired. We have now found that by using certain chelate diamine adducts of a metal halide in the reaction with the salt of the cyclopentadienyl ligand, enhanced formation of the racemic isomer and/or better product yields can be produced, especially by using a mixed ether-hydrocarbon reaction solvent medium and/or by preparing the adduct at elevated temperatures.
In accordance with this invention there is provided a process for preparing a chiral metallocene, said process comprising reacting a salt of an asymmetric bis(cyclopentadienyl) moiety containing ligand with a chelate diamine adduct of a transition, lanthanide or actinide metal halide in an organic solvent medium so as to produce said chiral metallocene.
Chiral metallocenes which can be prepared in accordance with the process of the invention preferably contain a metal from Groups 3-10, or the lanthanide and actinide series of the Periodic Table of the elements and, more preferably a Group 4 to 6 transition metal, which is coordinated with a ligand containing a pair of cyclopentadienyl moieties, at least one of which is asymmetric, which moieties are stereorigid such as by being joined by a bridging group. The cyclopentadienyl moieties can be substituted with one or more groups, such as halogen, amino, mercapto, phosphino, and C.sub.1 to C.sub.20 hydrocarbyl, silahydrocarbyl, or halohydrocarbyl and the like and can include moieties which are condensed, multi-ring structures such as, for example, indenyl, benzoindenyl, or fluorenyl, which structures can be hydrogenated and/or further substituted. The other groups on the metal atom usually include hydride, halogen, hydrocarbyl or halohydrocarbyl having up to about 6 carbons. Such chiral metallocenes, and their use as catalysts in forming isotactic olefin polymers are described, for example, in U.S. Pat. Nos. 5,017,714; 5,036,034; 5,145,819; 5,296,434; 5,324,800 and 5,329,033, whose disclosures are incorporated herein by reference. Typical bridging groups include silicon containing bridges of 1-4 atoms selected from silanylene, silaalkylene, oxasilanylene and oxasilaalkylene, such as, dimethylsilanylene. The chiral metallocenes are mixtures of racemic diasteriomers which have no plane of symmetry. In contrast, the meso isomers have a plane of symmetry running through the metal between the rings and are, therefore achiral.
Specific, non-limiting examples of chiral metallocenes include racemic: dichloride; dichloride; nium dichloride; onium dichloride; dichloride; nyl)!zirconium dichloride; -tetramethyldisilanylene)-bis(4,5,6,7-tetrahydroindenyl)!zirconium dichloride; ,4-disiianylbutylene)-bis(4,5,6,7-tetrahydroindenyl)!zirconium dichioride; m dichloride; dichloride; ium dichoride; nium dichoride; dichloride; nyl)!titanium dichloride; -tetramethyldisilanylene)-bis(4,5,6,7-tetrahydroindenyl)!titanium dichiori
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Balhoff John F.
DeSoto Troy E.
Lin Ronny W.
Power John M.
Strickler Jamie R.
Albemarle Corporation
Nazario-Gonzalez Porfirio
Pippenger Philip M.
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