Organic compounds -- part of the class 532-570 series – Organic compounds – Heterocyclic carbon compounds containing a hetero ring...
Reexamination Certificate
2001-02-15
2001-10-23
Nazario-Gonzalez, Porfirio (Department: 1621)
Organic compounds -- part of the class 532-570 series
Organic compounds
Heterocyclic carbon compounds containing a hetero ring...
C549S210000, C556S054000, C556S056000
Reexamination Certificate
active
06307063
ABSTRACT:
FIELD OF THE INVENTION
This invention relates to the conversion of compounds of titanium in a plus 4 (IV) oxidation state to similar compounds in which titanium is in a plus 3 (III) oxidation state.
More particularly, the invention relates to the reduction of TiCl
4
with particulate titanium in the presence of an ether which forms a TiCl
3
complex insoluble in the reaction medium.
BACKGROUND OF THE INVENTION
It is known to reduce TiCl
4
ether complexes pre-formed in the same pot or made during the reduction reaction with aluminum or magnesium powders, aluminum ribbon, alkyls, hydrides and lithium alkyls.
U.S. Pat. No. 6,093,833 describes a process for producing a trivalent titanium coordination complex by the reduction of a Ti(IV) salt. The process comprises the steps of (a) forming a complex by adding a stoichiometric excess of an ether to a Ti(IV) salt, and then (b) reducing the complex with a metal powder, specifically a magnesium or an aluminum powder, which forms a soluble magnesium or aluminum chloride complex by-product in the ether medium.
Also, the TiCl
3
.adduct produced is contaminated with small amounts of magnesium halide or aluminum halide salts.
SUMMARY OF THE INVENTION
This invention provides a method for converting a Ti(IV) compound to a complex of a Ti(III) compound. The complex is free of foreign metal contaminations. A preferred embodiment of the invention entails the treatment of TiCl
4
in the presence of an ether, preferably tetrahydrofuran or dimethoxyethane, with particulate titanium metal to form a high yield of a TiCl
3
.ether complex.
GENERAL DESCRIPTION OF THE INVENTION
In general, the invention may include reducing a Ti(IV) compound with particulate Ti, wherein a corresponding Ti(III) compound is produced. The reaction is conducted in the presence of an ether reactant which forms a coordination complex with the Ti(III) compound.
The invention is illustrated by generic equation 1:
wherein the mesh size of the particulate titanium is not more than about 100, X is a monovalent anion, preferably a halogen, and Z is an ether which forms a TiCl
3
complex insoluble in the reaction medium. The optional solvent is preferably an aromatic hydrocarbon, e.g., toluene. The reaction is preferably conducted by reflux at 90-100° C. for about 4 to 7 hours.
Titanium metal is oxidized to Ti(III), and Ti(IV) is reduced to Ti(III) giving a product free of contamination from other metal halides.
REFERENCES:
patent: 5264590 (1993-11-01), Strickler
patent: 5367085 (1994-11-01), Strickler
patent: 6093833 (2000-07-01), Kershner
Boulder Scientific Company
Irons Edward S.
Nazario-Gonzalez Porfirio
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