Polymerisation catalyst

Details Polymerisation catalyst Polymerisation catalyst

2000-11-08

2003-04-29

Wu, David W. (Department: 1713)

Synthetic resins or natural rubbers -- part of the class 520 ser

Synthetic resins

Polymers from only ethylenic monomers or processes of...

C526S348000, C526S161000, C526S135000, C526S147000, C526S111000, C502S167000

Reexamination Certificate

active

06555636

ABSTRACT:

The present invention relates to novel catalyst compositions and to the polymerisation of olefinically unsaturated monomers using said catalyst compositions.
A recent development in the control of radical polymerisation systems is atom transfer radical polymerisation (ATRP) based on a redox reaction with a transition metal compound. ATRP is believed to result from two parameters (i) the presence of a low constant concentration of growing radicals and (ii) a fast and reversible equilibrium between the growing radicals and the dormant polymer species. If the concentration of growing radicals is kept low enough and a fast and reversible equilibrium between growing radicals and the dormant polymer species is established the proportion of termination reactions in comparison to propagation can be minimised which results in better predictability of molecular weight and lower polydispersities. A more detailed discussion of the mechanism of ATRP may be found in Patent Application No. WO 96/30421.
Patent Application No. WO 96/30421 describes a method for atom or group transfer radical polymerisation of an alkene such as styrene whereby the alkene is polymerised in the presence of an initiator, a transition metal compound and a ligand and the formed polymer is subsequently isolated. The use of an alkyl halide initiator, copper (I) chloride, and bipyridine ligand to produce controlled molecular weight polymers of low polydispersity is described.
However the process described in WO 96/30421 has the disadvantage that it is a heterogeneous system due to the fact that the copper catalyst is only partially soluble in the polymerisation system. Thus it is difficult to determine the level of active catalyst in polydispersity of the final product. Heterogeneous catalysts are also known to be less efficient than homogeneous catalysts in terms of g/g productivity, and also require specific separation steps from the product in commercial use. As a result, homogeneous systems are generally preferred where possible.
Patent Application No. WO 97/47661 describes the use of copper diimine complexes which allow homogeneous atom transfer polymerisation of olefinically unsaturated monomers and thus the level of active catalyst in the mixture to be controlled. However rates of conversion for styrene using these complexes are relatively low, and polydispersities (Mw/Mn) relatively high.
SUMMARY OF THE INVENTION
It has now been surprisingly found that by using a catalyst system which includes particular iron complexes improved control over the activity of the catalyst system can be achieved, thereby ultimately providing an improved product.
According to the present invention there is provided a catalyst composition comprising
(i) an initiator having a radically transferable atom or group, and
(ii) a component of Formula I
[Fe[T] L] . (T/b)X  Formula I
wherein
Fe is iron and T its oxidation state
L is a ligand of Formula II
R
1
—N═CH—(CH
2
)
n
—CH═N—R
2
  Formula II
in which R
1
and R
2
are independently selected from C
1
-C
10
alkyl, aryl and substituted aryl, and n is 0 or 1;
X represents an atom or group covalently or ionically bonded to Fe;
b is the valency of the atom or group X.
DETAILED DESCRIPTION OF THE INVENTION
The initiator suitable for use in the present invention may be any initiator having a radically transferable atom or group. Examples of suitable initiators include conventional atom transfer radical addition initiators, for example, organic halides, such as alkyl halides, e.g. alkyl chlorides or bromides such as CCl
4
, CHCl
3
and CCl
3
Br, activated alkyl halides e.g. alkyl halides containing at least one alpha-electron withdrawing group such as an ester, e.g. 2-bromoethylisobutyrate or a ketone, e.g. 2-bromoisobutyrophenone or an optionally substituted aryl e.g. phenyl or nitro-substituted phenyl. Other suitable initiators include arenesulphonyl chlorides which can be substituted or unsubstituted such as para-toluenesulphonyl chloride and para-methoxybenzenesulphonyl chloride. Preferred initiators include CCl
4
and para-toluenesulphonyl chloride.
It will be understood that such initiators may also be molecules (monomeric or polymeric) which contain more than one radically transferrable atom or group. Examples of monomeric multifunctional initiators include alkyl dihalides and sulphonyl halides such as 1,3-benzene disulphonyl chloride. Suitable initiators for the invention also include polymers, which may optionally be based on styrene, which contain one or more radically transferable group present at the chain ends and/or pendent to the main chain and distributed along its length. It will be understood that such multifunctional initiators provide access to star branched and grafted polymer architectures with the enhanced potential to fine-tune properties.The use of mixed initiators is also within the scope of the invention.
In the Formula I, Fe may be Fe(II) or Fe(III), most preferably Fe(II). The atom or group represented by X in the Formula I is preferably selected from halide, sulphate, nitrate, thiolate, thiocarboxylate, BF
4
-, PF
6
-, hydride, carboxylate, triflate, cyano, arylsulphonate, hydrocarbyl, substituted hydrocarbyl, heterohydrocarbyl, C
1
-C
6
alkoxy. Examples of such atoms or groups are chloride, bromide, fluoride, iodide, phenyl, benzyl, methoxide, ethoxide, isopropoxide, tosylate, benzenesulphonate, toluenesulphonate, formate, acetate, phenoxide and benzoate. Most preferred is chloride.
R
1
and R
2
are independently C
1
-C
10
alkyl or aryl or substituted aryl. When one or both of R
1
and R
2
is C
1
-C
10
alkyl, it is for example, methyl, ethyl, n-propyl, i-propyl, n-butyl, t-butyl, n-hexyl, n-octyl, and n-decyl. C
1
-C
6
alkyl is generally preferred, especially t-butyl.
When one or both of R
1
and R
2
is aryl, it is preferably C
6
-C
10
aryl, for example, phenyl.
When one or both of R
1
and R
2
is a substituted aryl group, it may have from 7 to 24 carbon atoms, and be substituted at e.g. one or both ortho positions and/or the para position with, for example, C
1
-C
6
alkyl such as methyl, ethyl, n-propyl, i-propyl, n-butyl, t-butyl, especially t-butyl. An example is 2,6 di-i-propyl phenyl.
Preferably R
1
and R
2
are the same: preferably n is zero.
A preferred combination is where R
1
and R
2
are each 2,6 di-isopropyl phenyl and n=0. An especially preferred combination is where R
1
and R
2
are each t-butyl and n=0.
Compounds of Formula II can be prepared using procedures known to the man skilled in the art and disclosed in published literature for example as described in Z. Naturforsch, 1981, 36b, 823.
The present invention further provides a process for the polymerisation and copolymerisation of a radically polymerisable monomer comprising contacting the monomer under polymerisation conditions with the catalyst composition of the present invention. A further aspect of the invention is the use of the above-defined composition as a polymerisation catalyst for radically polymerisable monomers.
Monomers suitable for use in the polymerisation process of the present invention include any radically polymerisable monomer. Preferred monomers include ethylene; optionally substituted conjugated dienes such as 1,3-butadiene, isoprene; acids and anhydrides such as acrylic acid or acrylic anhydride; (meth)acrylamides; vinyl halides e.g. vinyl chloride; (meth)acrylonitrile; (meth)acrylate esters of C
1
-C
20
alcohols e.g. methyl methacrylate, ethyl methacrylate, propyl methacrylate (all isomers), butyl methacrylate (all isomers); vinyl esters of C
1
-C
20
alcohols e.g. vinyl acetate, vinyl propionate or vinyl butyrate; vinyl amides such as vinyl pyrrolidone, and other vinyl amides having up to 8 carbon atoms; vinyl ketones such as ethylvinyl ketone, butylvinyl ketone and other vinyl ketones having up to 8 carbon atoms; vinyl substituted aryls e.g. vinyl substituted phenyls, vinyl substituted naphthyls. The aryl ring may be substituted by at least one vinyl group such as 1-2 vinyl groups. Example

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