Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – Polymers from only ethylenic monomers or processes of...
Reexamination Certificate
2001-04-05
2004-05-18
Egwim, Kelechi C. (Department: 1713)
Synthetic resins or natural rubbers -- part of the class 520 ser
Synthetic resins
Polymers from only ethylenic monomers or processes of...
C524S836000, C526S348000, C526S352000, C526S352200
Reexamination Certificate
active
06737483
ABSTRACT:
The invention relates to a process for the polymerization of at least one olefin in the presence of at least one catalyst comprising at least one E—M—X linkage, in which E represents an oxygen or sulfur atom, M represents a nickel or palladium or platinum atom and X represents a phosphorus, arsenic or antimony atom, in a medium comprising a continuous liquid phase which comprises more than 30% by weight of water. The liquid phase comprising more than 30% by weight of water is subsequently referred to as the “aqueous phase”.
The polymerization of olefins by Ziegler catalysis usually involves highly hydrolyzable, indeed even pyrophoric, compounds (catalyst and cocatalysts) and it is desirable to be able to employ catalysts which are less problematic to handle, transport and store. Furthermore, there exists a need for polymerization processes in water, water being one of the easiest compounds to obtain access to and being a preferred solvent in numerous applications (coatings or adhesives, for example).
Nickel catalysts have been disclosed for operating in essentially organic media, as in the following documents: U.S. Pat. No. 4,711,969, U.S. Pat. No. 5,030,606 and BG 60319.
The process according to the invention involves a catalyst comprising at least one nickel or palladium or platinum atom and involves a high proportion of water.
The process according to the invention responds to the abovementioned problems and leads to a polyolefin with a high productivity in a water-rich medium. Furthermore, the process according to the invention does not require the use of a cocatalyst capable of activating the metal of the catalyst.
The invention furthermore opens a novel access route to polyolefin latices.
In the catalyst to which the invention makes recourse, the E—M—X linkage preferably forms part of a ring comprising five atoms, two of which are carbon atoms bonded to one another via a double bond.
Generally, the metal M is bonded, before its introduction into the polymerization medium, to a ligand L. This ligand L has in particular the role of stabilizing the structure of the catalyst before it is used and of facilitating the storage and handling thereof. Before or during the polymerization, a scavenger compound is brought together with the catalyst so as to separate the ligand L from the metal M and to allow the polymerization to take place. Without the present explanation constituting in any way a limitation on the scope of the present application, it seems that the distancing of the ligand, by allowing the olefin to approach the metal M, plays an important role in the catalytic polymerization mechanism.
Thus, in the context of the present application, when a catalyst is represented so that its metal M, which can be Ni, Pd or Pt, comprises a nonattributed valency represented by a dash, as in -M, it should be understood that this valency plays the role which has just been explained, namely to be occupied by a ligand L and to be released from the ligand for the polymerization.
The catalyst may comprise only a single atom of metal M. Such a catalyst, said to be monometallic, can comprise, for example, the structure represented by the formula (1)
in which the R
1
, R
2
, R
3
, R
4
and R
5
radicals, which can be identical or different, can be chosen from hydrogen, alkyl, cycloalkyl, aryl, alkylaryl or arylalkyl radicals, halogens, the hydroxyl radical, alkoxide radicals, —C(O)OR′, in which R′ represents a hydro-carbonaceous radical which can comprise from 1 to 15 carbon atoms, or —SO
3
Y, in which Y is chosen from Li, Na, K, NH
4
⊕
or NR″
4
⊕
, in which R″ represents a hydro-carbonaceous radical which can comprise from 1 to 15 carbon atoms, E, M and X having the meanings given above and it being possible for the nonattributed valency connected to M, represented by a dash in the above formula, to be occupied by a ligand L to facilitate the use of the catalyst, as has already been explained.
The linkage(s) of the E—M—X type of the catalyst can be such that M is a nickel atom, E is an oxygen atom and X is a phosphorus atom.
The catalyst preferably comprises at least two E—M—X linkages.
The E—M—X linkages are preferably separated from one another via intermediate atoms bonded to one another via covalent or coordination bonds, the minimum number of atoms between two M atoms preferably ranging from 6 to 42. The term “minimum number of atoms between two M atoms” is understood to mean the minimum number of atoms which is encountered in the molecule of the catalyst when moving from one of the M atoms to the other of the M atoms by following the bonds atom by atom. By way of example, if the catalyst comprises the structure:
in which Ph represents a phenyl radical, the minimum number of atoms between the Ni atoms is 8 (which corresponds to the linkage: —O—C—C—C—C—C—C—O—), as it is not possible to encounter fewer than 8 atoms when moving from the first Ni to the second Ni.
The catalyst may comprise only two M atoms in its structure.
The catalyst can; for example, be one of those represented by the following formula (2):
in which the R
6
, R
7
, R
8
, R
9
, R
10
, R
11
, R
12
and R
13
radicals, which can be identical or different, can be chosen from the same list of radicals as R
1
to R
5
above, E′—M′—X′ and E″—M″—X″ being two linkages of E—M—X type which can be identical or different and R being a bivalent radical.
The R radical can be chosen from bivalent hydrocarbonaceous radicals comprising, for example, 2 to 38 carbon atoms, such as alkylene, alkenylene, arylene, cycloalkylene, bicycloalkylene or alkylarylene radicals. The R radical can also be a 1,1′-ferro-cenylene radical which can be substituted, for example by one or two monovalent radicals such as —C(O)OR′ or —SO
3
Y, R and Y having the meanings already given.
By way of examples, the catalyst can be one of those comprising the structures hereinbelow:
in which Ph represents a phenyl radical, —(5,6-NBEN)— represents a 5,6-bicyclo[2,2,1]hept-2-ene radical, that is to say which can be represented by:
and —(1,1′-Fc)— represents a 1,1′-ferrocenylene radical.
In order to achieve better preservation of the integrity and thus of the effectiveness of the catalyst during its storage before use in polymerization, it is advisable to complex the atoms of metal M with a ligand L, so as to protect said M atoms by steric hindrance. Such protection is recommended in order to minimize the risks of reduction of the M atom, which can be reflected by a fall in or a loss of activity of the catalyst.
When the catalyst is used in polymerization, it is advisable to separate the ligand L from the M atom or atoms so that the latter can play their role in the activation of the polymerization reaction. The ligand can be separated before the polymerization and may even not be introduced into the polymerization medium. However, it may be left in the polymerization medium and may be even be introduced into the polymerization medium in the form complexed with the catalyst, provided that said medium comprises a scavenger compound capable of complexing of or combining in any appropriate fashion with the ligand so as to release the atoms of metal M from their complexing and thus to facilitate the polymerization. The scavenger compound must form a bond with the ligand which is sufficiently strong for the ligand to release the catalyst. It is generally possible to make use of the ligand from the synthesis of the catalyst, so that the formation of the catalyst takes place in the form complexed with the ligand.
Thus, for example, in the case of the bimetallic catalyst corresponding to the formula
in which the R and R
6
to R
13
radicals have the meanings already given in the context of the formula (2), said catalysts can be prepared by reaction of a bis(&agr;-ketoylide) with a nickel(0) compound in the presence of triphenylphosphine (PPh
3
), which acts as ligand, according to the following reaction scheme:
COD representing a cis,cis-1,5-cyclooctadiene radical
Drujon Xavier
Saudemont Thierry
Spitz Roger
Tomov Atanas
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