Organic compounds -- part of the class 532-570 series – Organic compounds – Heterocyclic carbon compounds containing a hetero ring...
Reexamination Certificate
2002-04-24
2004-04-13
Ramsuer, Robert W. (Department: 1626)
Organic compounds -- part of the class 532-570 series
Organic compounds
Heterocyclic carbon compounds containing a hetero ring...
Reexamination Certificate
active
06720429
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a thiocarbonylthio compound, and more particularly to a radical polymerization process for preparing polymers of vinyl monomers with controlled molecular weight and narrow polydispersity in the presence of the thiocarbonylthio compound.
2. Background of the Invention
Radical polymerization is one of the polymerization processes which are most widely exploited industrially because of the variety of the polymerizable monomers (>50% of the commercial polymers), of the ease of application and of the synthesis processes employed (emulsion, suspension, bulk, solution). However, in conventional radical polymerization it is difficult to control the size of the polymer chains and the molecular mass distribution. The polymers thus prepared contain chains of very large and very small masses (broad polydispersity), and this results in materials with uncontrolled properties.
Anionic and cationic polymerization techniques, for their part, allow proper control of the process, but the reaction conditions which these polymerization methods require are not always capable of being implemented on an industrial scale. In addition, many monomers cannot be polymerized using these techniques.
Living free radical polymerization is a recently developed technique for the controlled polymerization of vinyl monomers. The significant advantages of this technique permits the preparation of a wide range of different materials which are either difficult to prepare, or not available by other polymerization processes. The architecture, composition of the backbone, inclusion of functionality, and high degree of control over the molecular weight and polydispersity can be achieved by living free radical polymerization.
WO 98/01478 have reported a process of living free radical polymerization which teaches that in the presence of a suitable thiocarbonylthio compound (Z—C(═S)—S—R, RAFT-agent) to an otherwise conventional free radical polymerization. The so-called RAFT is the abbreviation of reversible addition-fragmentation chain transfer. A polymer with narrow molecular weight distribution can be obtained and the polymer chain length can be freely controlled.
This invention relates to a new thiocarbonylthio system, resulting in a much faster rate for vinyl monomers while still retaining a high degree of control over the molecular weight and polydispersity.
SUMMARY OF THE INVENTION
The object of the present invention is to provide a thiocarbonylthio compound.
Another object of the present invention is to provide a thiocarbonylthio compound that can control the radical polymerization of vinyl monomers in a quasi-living manner. Thiocarbonylthio compound of the present invention enhances the rate of polymerization while maintaining low polydispersity.
To achieve the above-mentioned objects, the thiocarbonylthio compound of the present invention is represented by formula (I)
Wherein
n is an integer of 0 to 3;
R
1
is alkyl, haloalkyl, alkenyl, aryl, alkylaryl, haloalkylaryl, arylalkyl, aminoalkyl, alkylamino, alkoxy, alkoxyaryl, alkyl sulfide, or alkylsilyl;
R
2
and R
3
are independently H, alkyl, haloalkyl, alkenyl, aryl, alkylaryl, arylalkyl, aminoalkyl, alkylamino, alkoxy, alkyl sulfide, or alkylsilyl;
R
4
and R
5
are independently H, alkyl, haloalkyl, alkenyl, aryl, alkylaryl, arylalkyl, aminoalkyl, alkylamino, alkoxy, alkyl sulfide, or alkylsilyl, or R
4
and R
5
link together with the carbon atoms to which they are attached to form a ring system; and
Y is O or S.
The living free radical polymerization process of the present invention includes polymerizing at least one kind of vinyl monomer in the presence of the thiocarbonylthio compound represented by formula (I).
DETAILED DESCRIPTION OF THE INVENTION
The present invention provides a thiocarbonylthio compound represented by formula (I)
Wherein
n is an integer of 0 to 3;
R
1
is alkyl, haloalkyl, alkenyl, aryl, alkylaryl, haloalkylaryl, arylalkyl, aminoalkyl, alkylamino, alkoxy, alkoxyaryl, alkyl sulfide, or alkylsilyl;
R
2
and R
3
are independently H, alkyl, haloalkyl, alkenyl, aryl, alkylaryl, arylalkyl, aminoalkyl, alkylamino, alkoxy, alkyl sulfide, or alkylsilyl;
R
4
and R
5
are independently H, alkyl, haloalkyl, alkenyl, aryl, alkylaryl, arylalkyl, aminoalkyl, alkylamino, alkoxy, alkyl sulfide, or alkylsilyl, or R
4
and R
5
link together with the carbon atoms to which they are attached to form a ring system; and
Y is O or S.
Alkyl referred to in the present invention may contain from 1 to 18, preferably from 1 to 10, carbon atoms. Haloalkyl may have 1 to 18, preferably from 1 to 10, carbon atoms. An example is chloromethyl (—CH
2
Cl). Aryl may have 6 to 10 carbon atoms, such as phenyl. Alkylaryl or arylalkyl may have 7 to 20, preferably from 7 to 15, carbon atoms. An example of alkylaryl is methylphenyl (—C
6
H
4
—CH
3
), and an example of arylalkyl is phenylmethyl (—CH
2
—C
6
H
5
). Haloalkylaryl may have 7 to 20, preferably from 7 to 15, carbon atoms. An example of haloalkylaryl is trifluoromethylphenyl.
Aminoalkyl referred to in the present invention may contain from 1 to 18, preferably from 1 to 10, carbon atoms. The aminoalkyl may be primary, secondary, or tertiary. Examples include aminomethyl (—CH
2
—NH
2
), methylaminomethyl (—CH
2
—NH(CH
3
)), and dimethylaminomethyl (—CH
2
—N(CH
3
)
2
).
Alkylamino referred to in the present invention may contain from 1 to 18, preferably from 1 to 10 carbon atoms. The alkylamino may be secondary or tertiary. Examples include methylamino (—NH—CH
3
) and dimethylamino (—N(CH
3
)
2
).
Alkoxy referred to in the present invention may contain from 1 to 18, preferably from 1 to 10, carbon atoms. Examples include methoxy and ethoxy. Alkoxyaryl referred to in the present invention may contain from 7 to 24, preferably from 7 to 16 carbon atoms. An example of alkoxyaryl is methoxyphenyl.
Alkyl sulfide may contain from 1 to 18, preferably from 1 to 10, carbon atoms. An example is methyl sulfide (—S—CH
3
). Alkylsilyl may contain from 1 to 20, preferably from 1 to 10, carbon atoms. Examples include trimethylsilyl (—Si(CH
3
)
3
), dimethylsilyl (—SiH(CH
3
)
2
), and dimethylethylsilyl (—Si(CH
3
)
2
(C
2
H
5
)).
Preferably, R
1
is alkyl, aryl, alkylaryl, alkoxyaryl, or haloalkylaryl, and R
2
and R
3
are independently H, alkyl, haloalkyl, alkenyl, aryl, alkylaryl, or arylalkyl.
R
4
and R
5
can be independently H, alkyl, haloalkyl, alkenyl, aryl, alkylaryl, arylalkyl, aminoalkyl, alkylamino, alkoxy, alkyl sulfide, or alkylsilyl, and preferably H, alkyl, haloalkyl, alkenyl, aryl, alkylaryl, or arylalkyl. Or, alternatively, R
4
and R
5
can link together with the carbon atoms to which they are attached to form a ring system having from 4 to 20 carbon atoms. The ring system can be a saturated ring or an unsaturated ring such as an aromatic ring.
According to a preferred embodiment of the present invention, the thiocarbonylthio compound of the present invention can be represented by formula (II),
Wherein
n is an integer of 0 to 3;
R
1
is alkyl, haloalkyl, alkenyl, aryl, alkylaryl, haloalkylaryl, arylalkyl, aminoalkyl, alkylamino, alkoxy, alkoxyaryl, alkyl sulfide, or alkylsilyl;
R
2
and R
3
are independently H, alkyl, haloalkyl, alkenyl, aryl, alkylaryl, arylalkyl, aminoalkyl, alkylamino, alkoxy, alkyl sulfide, or alkylsilyl;
Y is O or S.
Compared to the thiocarbonylthio compounds reported in WO 98/01478, the above thiocarbonylthio compound is easy to synthesize and obtained as crystals in high yield. No further purification method like column chromatography is required.
In the presence of the thiocarbonylthio compound represented by formula (I) of the present invention, the polymerization has living characteristics and provides polymers of controlled molecular weight and low polydispersity.
The monomer that is polymerized can be one vinyl monomer alone, or in combination with one or more polymerizable vinyl comonomers.
Specific monomers include the followings: acrylic acid and its salts, acrylates, methacrylic acid and
Mathew Lizamma
Shih Kuo-Chen
Industrial Technology Research Institute
Ramsuer Robert W.
Small Andrea D.
LandOfFree
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