Catalyst – solid sorbent – or support therefor: product or process – Catalyst or precursor therefor – Organic compound containing
Reexamination Certificate
1999-04-28
2003-08-12
Bell, Mark L. (Department: 1755)
Catalyst, solid sorbent, or support therefor: product or process
Catalyst or precursor therefor
Organic compound containing
C502S155000, C502S157000, C502S171000
Reexamination Certificate
active
06605564
ABSTRACT:
FIELD OF THE INVENTION
This invention relates to novel compositions of an anionic polymerization initiator and an additive which enhance functionalization of living polymer anions; novel compositions of electrophiles and an additive which enhance functionalization of living polymer anions; and processes which employ these compositions, or an additive, for improved efficiency in the functionalization of living polymer anions.
BACKGROUND OF THE INVENTION
Polymers that contain terminal functional groups are industrially important. One technique to prepare these terminally functionalized polymers is by reaction of a suitable electrophile with a living polymer anion. For numerous examples of end group functionalization chemistry, see Hsieh, H. L.; Quirk, R. P.
Anionic Polymerization: Principles and Practical Applications
; Marcel Dekker: New York, N.Y., 1996, pages 261-306.
Some of these functionalization reactions are not very efficient, particularly for the preparation of telechelic polymers, due to the formation of a thick gel during the functionalization. This leads to lower capping efficiency. See, for example, U.S. Pat. No. 5,393,843, Example 1, wherein the capping efficiency was only 82%.
A recently reported terminal functionalization technique uses a protected functionalized electrophile. For instance, Nakahama and co-workers have described the reaction of polystyryllithium with the electrophile Br—(CH
2
)
3
C(OCH
3
)
3
, a protected carboxyl group. See Hirao, A.; Nagahama, H. Ishizone, T.; Nakahama, S.
Macromolecules
, 1993, 26, 2145. Excellent terminal functionalization of the living anion was achieved (>95%). Other examples of efficient functionalization with protected functionalized electrophiles are reported in Ueda, K.; Hirao, A.; S. Nakahama, S.
Macromolecules
, 1990, 23, 939; Tohyama, M.; Hirao, A.; Nakahama, S.
Macromol. Chem. Phys
. 1996, 197, 3135, and Labeau, M. P.; Cramail, H.; Deffieux, A.
Polymer International
, 1996, 41, 453.
To obtain efficient functionalization, these functionalization reactions are conducted in tetrahydrofuran (THF) at −80° C. THF, however, is an expensive solvent, and these low-temperature conditions are not practical on an industrial scale. In addition, efficient functionalization of polymer anions was only observed with expensive alkyl bromides.
SUMMARY OF THE INVENTION
The present invention provides compositions capable of increasing efficiencies in the functionalization of living polymer anions. The compositions include as a component one or more additives, such as an alkali halide or alkali alkoxide. The inventors have unexpectedly found that the additives are capable of improving the efficiency of reactions between polymer anions and electrophiles, as compared to similar reactions in the absence of an additive. In one aspect of the invention, the compositions include one or more additives and one or more anionic polymerization initiators. Exemplary anionic polymerization initiators include non-functionalized and functionalized organoalkali metal initiators. In another aspect of the invention, the compositions include one or more additives and one or more electrophiles useful for functionalizing living polymers.
Processes for improving living polymer anion functionalization are also provided. In this aspect of the invention, a living polymer anion is functionalized using a suitable electrophile in the presence of one or more additives as described above. Higher yields of functionalized polymers were observed when the additive was employed. In addition, the employment of the additive allowed the functionalization to be performed in hydrocarbon solvent at room temperature. Further, these reaction conditions are much less expensive on a commercial scale, as compared to the prior art. The invention can also be used with a variety of monomers and/or functionalizing agents. For example, it was discovered that the less expensive, and more readily available, alkyl chlorides afford efficient functionalization when an additive is employed.
Yet another embodiment of the invention provides novel electrophiles. The novel electrophiles have the formula
wherein:
X is halogen selected from chloride, bromide and iodide;
Z is a branched or straight chain hydrocarbon connecting group which contains 1-25 carbon atoms, optionally substituted with aryl or substituted aryl;
T is selected from the group consisting of oxygen, sulfur, nitrogen, and mixtures thereof;
(A—R
1
R
2
R
3
) is a protecting group, in which A is an element selected from Group IVa of the Periodic Table of the Elements and R
1
, R
2
, and R
3
are each independently selected from the group consisting of hydrogen, alkyl, substituted alkyl, aryl, substituted aryl, cycloalkyl, and substituted cycloalkyl;
R, R
4
, and R
5
are each independently selected from the group consisting of hydrogen, alkyl, substituted alkyl, aryl, substituted aryl, cycloalkyl, and substituted cycloalkyl;
h is 0 when T is oxygen or sulfur, and 1 when T is nitrogen; and
l is an integer from 1 to 7.
DETAILED DESCRIPTION OF THE INVENTION
Additives useful in the invention include, but are not limited to, alkali halides, such as lithium chloride, lithium bromide, lithium iodide, sodium chloride, sodium iodide, potassium chloride, and mixtures thereof; alkali alkoxides, such as lithium t-butoxide, lithium s-butoxide, potassium t-butoxide, and mixtures thereof; and the like and mixtures thereof. The additives should be dried, prior to use.
Several factors influence the amount of additive required, such as the nature of the polymer anion; the identity of the hydrocarbon solvent; the presence of a polar additive (co-solvent); the amount of the polar additive; the nature of the electrophile; and the identity of the additive. An effective amount of the additive employed is from as little as 0.01 equivalents of the electrophile, up to greater than five equivalents again based on the electrophile. In general, less than ten equivalents of the additive are effective for increasing the efficiency of the functionalization reaction.
In one aspect of the invention, the compositions can include one or more organoalkali metal anionic polymerization initiators. Exemplary anionic polymerization initiators include alkyllithium initiatiors represented by the formula R′—Li, wherein R′ represents an aliphatic, cycloaliphatic, or arylsubstituted aliphatic radical. Preferably, R′ is an alkyl or substituted alkyl group of 1-12 carbon atoms. Such initiators include, but are not limited to, methyllithium, ethyllithium, n-propyllithium, 2-propyllithium, n-butyllithium, s-butyllithium, t-butyllithium, n-hexyllithium, 2-ethylhexyllithium, and the like and mixtures thereof. As used herein, alkyllithium initiators also include dilithium initiators as known in the art. See, for example, U.S. Pat. Nos. 5,393,843 and 5,405,911. Dilithium initiators can be prepared by the reaction of an alkyllithium reagent, such as s-butyllithium, with a compound having at least two independently polymerizable vinyl groups, such as the isomeric divinylbenzenes or isomeric diisopropenylbenzenes.
One or more functionalized organoalkali metal initiators may also be employed in the compositions of the invention. These functionalized initiators have the general structure shown below:
M—Q
n
—Z—T—(A—R
7
R
8
R
9
)
m
(I)
or
wherein:
M is an alkali metal selected from the group consisting of lithium, sodium and potassium;
Q is an unsaturated hydrocarbyl group derived by incorporation of one or more conjugated diene hydrocarbons, one or more alkenylsubstituted aromatic compounds, or mixtures of one or more dienes with one or more alkenylsubstituted aromatic compounds into the M—Z linkage;
n is an integer from 0 to 5;
Z is a branched or straight chain hydrocarbon connecting group which contains 3-25 carbon atoms, optionally substituted with aryl or substituted aryl;
T is selected from the group consisting of oxygen, sulfur, and nitrogen groups and mixtures thereof;
A (A—R
7
R
8
R
9
)
m
is a protecting group in which A is an element sel
Lee Young Joon
Letchford Robert James
Quirk Roderic Paul
Schwindeman James Anthony
Bell Mark L.
FMC Corporation
Myers Bigel Sibley & Sajovec P.A.
Pasterczyk J.
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