Catalyst – solid sorbent – or support therefor: product or process – Catalyst or precursor therefor – Organic compound containing
Reexamination Certificate
2001-08-15
2002-08-27
Solola, Taofiq (Department: 1626)
Catalyst, solid sorbent, or support therefor: product or process
Catalyst or precursor therefor
Organic compound containing
C548S402000, C548S420000
Reexamination Certificate
active
06440889
ABSTRACT:
FIELD OF THE INVENTION
The invention relates to a process for making olefin polymerization catalysts. In particular, the invention relates to a process for making Group 4 transition metal complexes that incorporate a single anionic indenoindolyl ligand.
BACKGROUND OF THE INVENTION
“Single-site” catalysts, which include metallocenes, actively polymerize olefins to give polymers with valuable properties such as narrow molecular weight distribution and uniform comonomer distribution. While traditional metallocenes have cyclopentadienyl (Cp) ligands and/or Cp-like ligands (e.g., indenyl, fluorenyl), a variety of non-metallocene, single-site catalysts having heteroatomic ring ligands havezalso been developed (see, e.g., U.S. Pat. Nos. 5,554,775 and 5,539,124).
In a series of articles, Professor Richard Jordan and coworkers at the University of Iowa describe the preparation of bridged metallocene complexes via an amine elimination approach (see
Organometallics
14 (1995) 5
; Organometallics
15 (1996) 4030, 4038, 4045; and
J. Am. Chem. Soc
. 118 (1996) 8024). In a typical example, 1,2-bis(3-indenyl)ethane reacts with tetrakis(dimethylamino)zirconium (Zr(NMe
2
)
4
) with elimination of two moles of dimethylamine to give bridged bis(dimethylamino)zirconium complexes (see Scheme 1 of the
J. Am. Chem. Soc
. article). Later in the same paper, halogenation or alkylation of the bis(dimethylamino) complex is described (Scheme 3). All of the complexes are bridged metallocenes.
U.S. Pat. No. 6,232,260 discloses single-site catalysts based on organometallic complexes that incorporate at least one indenoindolyl ligand. A typical indenoindolyl precursor is easily made by reacting 1-indanone with p-tolylhydrazine. Examples A and B in the '260 patent illustrate the preparation of a bis(indenoindolyl)zirconium dichloride complex from the reaction of two equivalents of an indenoindolyl monoanion and one equivalent of zirconium tetrachloride. Only bis(indenoindolyl)zirconium complexes are prepared.
PCT Int. Appl. WO 99/24446 describes many indenoindolyl complexes, including bridged complexes, bis(indenoindolyl) complexes, and non-bridged indenoindolyl(Cp) or indenoindolyl(Cp-like) complexes. All of the working examples show either bis(indenoindolyl) complexes or bridged complexes. Based on the reference teachings, which include a listing of many non-bridged indenoindolyl(Cp or Cp-like) complexes, one expects preparation of the latter complexes to be straightforward.
Recently, we became interested in finding a better way to make non-bridged Group 4 organometallic complexes that incorporate one indenoindolyl ligand and one Cp or Cp-like ligand. While these complexes can be made by reacting cyclopentadienylzirconium trichloride with one equivalent of an indenoindolyl monoanion, CpZrCl
3
is expensive. Moreover, Cp-like analogs of the starting material are not commercially available.
A logical approach would be to react inexpensive ZrCl
4
with one equivalent of an indenoindolyl monoanion, and then react the trichloride product with an anion from cyclopentadiene, indene, or fluorene:
This approach would provide flexibility in the choice of Cp or Cp-like ligand. Unfortunately, however, the initial reaction fails to provide indenoindolylzirconium trichloride selectively. In fact, as our experiments demonstrate, the trichloride product reacts so rapidly with more monoanion that the only isolated product is a bis(indenoindolyl)zirconium dichloride (see Comparative Example 7 below). This problem is not described in either U.S. Pat. No. 6,232,260 or PCT Int. Appl. WO 99/24446.
A valuable process would selectively give non-bridged Group 4 metal indenoindolyl complexes containing little or no bis(indenoindolyl) complex. Preferably, the route would permit flexibility in the choice of Cp or Cp-like ligand while avoiding costly starting materials. Ideally, the process would utilize versatile intermediates that provide pathways to other valuable indenoindolyl Group 4 metal complexes.
SUMMARY OF THE INVENTION
The invention is an improved process, based on amine elimination, for selectively making Group 4 metal complexes that incorporate a single indenoindolyl ligand. First, an indenoindole or its synthetic equivalent is reacted with about one equivalent of a tetrakis(dialkylamino) Group 4 metal compound. The reaction product, a tris(dialkylamino) metal complex, is a versatile intermediate that can be halogenated, alkylated, or reacted directly with cyclopentadiene precursors to produce a variety of valuable indenoindolyl-Group 4 metal complexes. The process selectively provides mono-indenoindolyl complexes, enables the economical preparation of desirable Cp- or Cp-like derivatives, and permits the use of an inexpensive Group 4 transition metal source.
DETAILED DESCRIPTION OF THE INVENTION
Catalysts prepared by the process of the invention are “single site” in nature, i.e., they incorporate distinct chemical species rather than mixtures of different species. They give polyolefins with characteristically narrow molecular weight distributions (Mw/Mn<3) and good, uniform comonomer incorporation.
In each process of the invention, the initial step involves reaction of an indenoindole or its synthetic equivalent with about one equivalent of a tetrakis(dialkylamino) Group 4 metal compound. The reaction produces a tris(dialkylamino) indenoindolyl Group 4 metal complex, and it eliminates one equivalent of a dialkylamine or a dialkylamino-functional side product.
By “indenoindole,” we mean an organic compound that has both indole and indene rings. The five-membered rings from each are fused, i.e., they share two carbon atoms. Preferably, the rings are fused such that the indole nitrogen and the only sp
3
-hybridized carbon on the indenyl ring are “trans” to each other. Such is the case in an indeno[1,2-b] ring system such as:
Suitable ring systems also include those in which the indole nitrogen and the sp
3
-hybridized carbon of the indene are beta to each other, i.e., they are on the same side of the molecule. This is an indeno[2,1-b]indole ring system:
The ring atoms can be unsubstituted or substituted with one or more groups such as alkyl, aryl, aralkyl, halogen, silyl, nitro, dialkylamino, diarylamino, alkoxy, aryloxy, thioether, or the like. Additional fused rings can be present, as long as an indenoindole moiety is present.
Numbering of indenoindoles follows IUPAC Rule A-22. The molecule is oriented as shown below, and numbering is done clockwise beginning with the ring at the uppermost right of the structure in a manner effective to give the lowest possible number to the heteroatom. Thus, 5,10-dihydroindeno[1,2-b]indole is numbered as follows:
while 5,6-dihydroindeno[2,1-b]indole has the numbering:
For correct nomenclature and numbering of these ring systems, see the
Ring Svstems Handbook
(1998), a publication of Chemical Abstracts Service, Ring Systems File II: RF 33986-RF 66391 at RF 58952. (Note that indenoindoles are incorrectly numbered in U.S. Pat. No. 6,232,260; more correct numbering appears in POT Int. Appl. WO 99/24446.)
Suitable indenoindoles useful in the process of the invention include, for example, 5,10-dihydroindeno[1,2-b]indole, 5,6-dihydroindeno[2,1-b]indole, 4,7-dimethyl-5,10-dihydroindeno[1,2-b]indole, 4-tert-butyl-8-methyl-5,10-dihydroindeno[1,2-b]indole, 4,8-dichloro-5,10-dihydroindeno-[1,2-b]indole, 2,7-dimethyl-5,6-dihydroindeno[2,1-b]indole, and the like.
Methods for making indenoindoles are well known. Suitable methods are disclosed, for example, in U.S. Pat. No. 6,232,260, the teachings of which are incorporated herein by reference, and references cited therein, including the method of Buu-Hoi and Xuong,
J. Chem. Soc.
(1952) 2225. Suitable procedures also appear in PCT Int. Appl. WO 99/24446.
A synthetic equivalent of an indenoindole can be used instead of an indenoindole. By “synthetic equivalent,” we mean a compound that functions in the same way as an indenoindole when rea
Equistar Chemicals LP
Murray Joseph
Schuchardt Jonathan L.
Solola Taofiq
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