Organic compounds -- part of the class 532-570 series – Organic compounds – Heavy metal containing
Reexamination Certificate
2000-06-19
2001-09-25
Nazario-Gonzalez, Porfirio (Department: 1621)
Organic compounds -- part of the class 532-570 series
Organic compounds
Heavy metal containing
C556S054000, C162S079000, C008S119000
Reexamination Certificate
active
06294682
ABSTRACT:
The present invention relates to solutions of alkoxides containing titanium or zirconium or hafnium and magnesium or calcium or strontium or barium, a process for their preparation, and their use.
Metal alcoholates and metal acid esters find a variety of applications in technical fields.
The preparation of Ziegler catalysts generally proceeds from metal alcoholates, a procedure which is known as such. Catalysts of this type containing vanadium or chromium are frequently employed in olefin polymerization in suspension or in the gas phase, although such catalysts containing vanadium or chromium are hardly desirable from a toxicological point of view.
Cellulose-containing materials, e.g., paper containing aluminum sulfate, are subject to degradation by acid. Large irreplaceable historic file and book stocks are threatened by destruction due to acid attack.
The use of lyes containing alkali or alkaline earth alcoholates as a neutralizing component for the treatment of such cellulose-containing materials has been described (U.S. Pat. No. 3,676,182) as early as 1966. As a preventive measure against excessive basicity, such a treatment may also contain predominantly acidic alkoxides, for example, of the elements aluminum, tin, boron, titanium or zirconium, although such measure is not detailed any further in the description or examples of the above mentioned U.S. Patent.
The preparation of complex alkoxides from the elemental metals, such as aluminum, magnesium, calcium, is known from basic work by Meerwein and Bersin (“Untersuchungen über Metallalkoholate und Orthosäureester”, Liebigs Ann. Chem. 476, 113-150). This method is not applicable to the elements titanium, zirconium and hafnium since a standstill of the reaction between a much more reactive alkali alcoholate and a titanic or zirconic ester on the level of low conversions has been described, and an even poorer reactivity could be predicted for alkaline earth alcoholates in connection with titanic or zirconic esters because of their reactivities which are anyway lower than that of the alkali alcoholates.
Our own studies have, indeed, shown that no formation of a compound occurs in common solutions or suspensions of alcoholates of the alkaline earth metals and of titanium or zirconium; the alcoholates employed are simultaneously present without reacting with one another. Even at the boiling temperature of the solution, no formation of complex alkoxides is observed when the solvent or suspension agent, e.g., hydrocarbons, such as hexane, heptane etc., aromatic hydrocarbons, e.g., xylene or toluene, or siloxanes, e.g., hexamethyldisiloxane, is removed under vacuum.
Indeed, the preservation method proposed at the time in U.S. Patent Specification No. 3,676,182 has not been applied beyond the experimental stage, in spite of great urgency, since it fails to meet a number of indispensible preconditions of such an application: for example, ensuring that the neutralizing agents, which often tend to be insoluble, are in a liquid form for a successful thorough treatment, i.e. for completeness of the paper impregnation, and especially harmlessness towards printing and stamping inks of the texts and illustrations, which must be preserved in a completely integral condition, and their bookbinding adjuvants.
DE-OS 41 38 750 discloses double alkoxides of the formula
Me
I
(OR)
x
·Me
II
(OR)
y
wherein Me
I
corresponds to an element of Group
4
of the Periodic Table, aluminum or tin, and Me
II
corresponds to an alkali or alkaline earth element, and in addition, the OR groups may be derived from different kinds of alcohols, e.g., dihydric or polyhydric alcohols; thus, compounds of two alkoxides employed in a ratio of 1:1 and having the same alkoxide groups, such as Al
III
(OC
2
H
5
)
3
·K
I
(OC
2
H
5
) or Sn
IV
(OC
3
H
7
)
4
·Mg
II
(OC
3
H
7
)
2
or Zr
IV
(O—C
2
H
4
—O)
2
·Ca
II
(O—C
2
H
4
—O), can be derived therefrom. Such double alkoxides are used as neutralizing agents, conveniently dissolved in an appropriate solvent (DE-OS 41 04 515), for example, alcohols, fluorohydrocarbons or fluorochlorohydrocarbons, naphtha hydrocarbons or siloxanes, for the large-scale deacidification of archives. There is a drawback in that the use of the above mentioned double alkoxides leaves evident powdery residues, for example, of the metal oxides or oxide hydrates, oxide hydroxides, the corresponding carbonates etc., after the large-scale deacidification. A further problem remaining unsolved is an improvement of mechanical stabilization of the paper sheets which are, as a rule, in a more or less impaired condition or already in beginning decomposition, which improvement is to be achieved simultaneously with the neutralization, if possible.
Thus, it has been the object of the present invention to provide mechanical stabilization of materials containing cellulose fibers in addition to the neutralization thereof, and a process for the preparation of a substance having such properties as to achieve this.
Surprisingly, it has been found that alkoxides of general formula I
[M
II
(OR)
2-y
(OR
1
)
y
]
n
·[M
IV
(OR
1
)
4-z
(OR)
z
] (I)
wherein
M
II
represents magnesium and/or calcium and/or strontium and/or barium; and
M
IV
represents titanium and/or zirconium and/or hafnium;
R is an alkyl residue of from 1 to 18 carbon atoms; and
R
1
is an alkyl residue of from 1 to 18 carbon atoms;
y takes a value of from 0 to 2; and
z takes a value of from 0 to 4; and
n is a number of between 0.001 and 3;
can be obtained by reacting at least one alkoxide of the elements magnesium and/or calcium and/or strontium and/or barium with at least one alkoxide of the elements titanium and/or zirconium and/or hafnium at a temperature which is in the range of the decomposition temperature of at least one of the alkoxides employed.
Substances which promote the formation of a melt can suitably be added to the reaction mixture of the individually employed alkoxides. In addition, the alkoxides of general formula I, which can be prepared by the process according to the invention, have particularly favorable properties when used for the preservation and/or stabilization of materials containing cellulose fibers. Further, alkoxides according to claim
1
and alkoxides prepared according to the process of claims
2
to
9
and their solutions are particularly suitable to be employed in the preparation of catalysts for the polymerization of olefins.
Thus, the present invention relates to solutions of alkoxides containing titanium and/or zirconium and/or hafnium and magnesium and/or calcium and/or strontium and/or barium having the general formula I
[M
II
(OR)
2-y
(OR
1
)
y
]
n
·[M
IV
(OR
1
)
4-z
(OR)
z
] (I)
wherein
M
II
represents magnesium and/or calcium and/or strontium and/or barium; and
M
IV
represents titanium and/or zirconium and/or hafnium;
R is an alkyl residue of from 1 to 18 carbon atoms; and
R
1
is an alkyl residue of from 1 to 18 carbon atoms;
y takes a value of from 0 to 2; and
z takes a value of from 0 to 4; and
n is a number of between 0.001 and 3, with the proviso that n is not 1, when y is 2 and z is 0 or y is 0 and z is 4.
Alkoxides of general formula I generally include compounds corresponding to a composition such as
[Mg(C
2
H
5
O)
2
]·[Ti(C
2
H
5
O)
3
(i—C
3
H
7
O)] (magnesium titanium (1:1) ethylate isopropylate); or
[Mg
0.5
Ca
0.5
(CH
3
O)
2
]
0.3
·[Ti(CH
3
O)
4
] (magnesium/calcium titanium (0.3:1) methylate); or
[Mg(C
2
H
5
O)
2
]
1.75
·[Zr(n-C
8
H
17
O)
4
] (magnesium zirconium (1.75:1) ethylate n-octylate); or
[Ba(C
2
H
5
O)
2
]·[Ti
0.9
Zr
0.1
(i—C
4
H
9
O)
4
] (barium titanium/zirconium (1:1) ethylate i-butylate).
The present invention further relates to a process for the preparation of alkoxides containing magnesium and/or calcium and/or strontium and/or barium and titanium and/or zirconium and/or hafnium, characterized in that alkoxides of general formula I
[M
II
(OR)
2-y
(OR
1
)
y
]
n
·[M
IV
(OR
1
)
4-z
(OR)
Horn Michael
Kotzsch Hans-Joachim
Rauleder Hartwig
Srebny Hans-Gunther
Standke Burkhard
E. I. Du Pont de Nemours and Company
Nazario-Gonzalez Porfirio
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