Preparation of cyclopentadienyl or indenyl titanium trihalides

Details Preparation of cyclopentadienyl or indenyl titanium trihalides Preparation of cyclopentadienyl or indenyl titanium trihalides

2002-01-08

2003-03-11

Nazario-Gonzalez, Porfirio (Department: 1621)

Organic compounds -- part of the class 532-570 series

Organic compounds

Heavy metal containing

C502S152000, C526S160000, C526S943000

Reexamination Certificate

active

06531619

ABSTRACT:

FIELD OF THE INVENTION
This invention relates to the preparation of cyclopentadienyl or indenyl titanium trihalides.
BACKGROUND OF THE INVENTION
Known methods for the synthesis, of cyclopentadienyl titanium trichlorides may require the use of titanium(III) trichloride, involve reduction-oxidation procedures, or the use of solvents, e.g., tetrahydrofuran (THF) or glyme, which are difficult to remove.
One such known synthesis entails treatment of pentamethyl cyclopentadiene with potassium tertiary butoxide to provide potassium pentamethyl cyclopentadiene which must then be treated with trimethyl silicon chloride (TMSCl) to obtain the desired pentamethyl cyclopentadienyl trichloride. The synthesis of the potassium pentamethyl cyclopentadiene results in a reaction mixture that contains tertiary butyl alcohol which is difficult to remove.
There is a need for an improved, cost effective synthesis of cyclopentadienyl and indenyl trichlorides which avoids these disadvantages.
SUMMARY OF THE INVENTION
A cyclopentadiene or indene is lithiated in THF or ethyl ether and treated with XTi (OiPr)
3,
wherein X is a halogen to produce a THF or ether solution of cyclopentadienyl or indenyl titanium tri-isopropoxide and a lithium halide. The THF or ethereal solvent is exchanged for a hydrocarbon solvent to precipitate the lithiumihalide which is separated by filtration. The mother liquor which contains cyclopentadienyl or indenyl titanium tri-isopropoxide is treated with SiCl
4
or BCl
3
to provide cyclopentadienyl or indenyl titanium trihalide.
DESCRIPTION OF THE INVENTION
In this specification, the expressions “cyclopentadiene” and “indene” mean cyclopentadiene or indene per se or any alkyl cyclopentadiene or alkyl indene which has one or more, preferably C
1
to C
6
alkyl ring substituents. The ring substituents may be the same or different.
Pursuant to one embodiment of the invention, a cyclopentadiene or an indene is deprotonated with butyllithium in THF or similar solvent in which the lithiated cyclopentadiene or indene and the lithium chloride are each soluble. Useful solvents other than THF include diethyl ether and monoglyme. ClTi(OiPr)
3
, in which the expression “(OiPr)” means isopropoxide, is added to the deprotonated reaction mixture which is then heated, preferably at reflux, for 6 to 8 hours to provide a second reaction mixture that contains a cyclopentadienyl or indenyl titanium tri-isopropoxide and lithium chloride.
The reaction mixture solvent is exchanged for an aliphatic hydrocarbon solvent, e.g., Isopar®E, to precipitate the LiCl which is removed by filtration.
The filtrate, a solution of a cyclopentadienyl or indenyl titanium tri-isopropoxide, is treated with SiCl
4
, AlCl
3
or BCl
3
, preferably at reflux in an amount at least stoichiometrically appropriate, to provide the corresponding cyclopentadiene titanium trichloride.
Any compound of the formula XTi (OR)
3
, in which X is a halogen, preferably chlorine, and R is an alkyl group, preferably a C
1
to C
6
alkyl group, may be used instead of ClTi (OiPr)
3
.


REFERENCES:
patent: 2917501 (1959-12-01), Drucker et al.
patent: 3046288 (1962-07-01), Sloan et al.
patent: 3072691 (1963-01-01), Gorsich
patent: 3080305 (1963-03-01), Gorsich
patent: 3161629 (1964-12-01), Gorsich
patent: 5721327 (1998-02-01), Santi et al.
patent: 5858904 (1999-01-01), Takeuchi et al.

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