Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – Polymers from only ethylenic monomers or processes of...
Reexamination Certificate
2002-05-15
2003-01-14
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...
C526S335000, C502S102000, C502S150000, C502S170000
Reexamination Certificate
active
06506865
ABSTRACT:
FIELD OF THE INVENTION
The present invention generally relates to NdHA
4
(A=carboxylate), a novel monomeric neodymium carboxylate, and its use in the polymerization of a conjugated diene, and more particularly to NdHA
4
and a catalyst system comprising the same, halogen and organic metal compounds, which are usable in the polymerization of 1,3-butadiene or isoprene.
BACKGROUND OF THE INVENTION
The following conventional methods for preparing neodymium carboxylates have a common feature that the chemical formula of the neodymium carboxylaytes is Nd(OOCR)
3
wherein R represents an alkyl group.
As disclosed in WO 97/36850, WO 98/39283, British Patent No. 2,140,435, EUP Nos. 512,346 and 599,096, U.S. Pat. Nos. 5,428,119, 5,449,387 and 5,360,898, and Polymer (Vol 26, p147, 1985), Nd(OOCR)
3
was obtained by reacting an aqueous solution of lanthanide chloride, lanthanide nitrate or lanthanide oxide with an aqueous carboxylate solution, and by extraction followed with an organic solvent.
U.S. Pat. No. 5,220,045 discloses a method for preparing a neodymium carboxylate by reacting an aqueous neodymium nitrate solution with an organic acid dissolved in an organic solvent in the presence of ammonia or an organic base, and removing water by azeotropic distillation.
A method for preparing lanthanide carboxylates using the ligand exchange method is also described by Paul, R. C., Singh, G., and Ghota, J. S. (Indian J. Chem. Vol 11, p294, 1973).
However, the neodymium catalyst system thus obtained by the above method has an activity of no more than 7% (see. Porri. L. et al., Polymer Preprint, 1998, Spring p214) and adversely cause gel formation in the 1,3-butadiene polymerization.
This results from the fact that the neodymium carboxylate, Nd(OOCR)
3
, has oligomeric or polymeric structures and contains lots of water, salts and bases which deteriorate the yield of in the polymerization and thereby lower the activity of the neodymium catalyst systems. In particular, the salts contained in the Nd(OOCR)
3
, e.g., nitrates, chlorides and sulfates are difficult to eliminate. Furthermore, the solvents used in the synthesis of neodymium carboxylate, such as water, alcohols (e.g., methanol, ethanol), ethers (e.g., tetrahydrofuran, ethylether) or dimethylformamides will have coordinate with neodymium to lower the catalyst activity as well as agglomeration of the catalyst.
On the other hand, a conventional process for preparing high 1,4-cis polybutadiene with the conventional neodymium carboxylate is disclosed, for example, in EUP Nos. 11184 and 652240, and U.S. Pat. Nos. 4,260,707 and 5,017,539, in which (1) neodymium carboxylate (Nd(OOCR)
3
) (2) an alkylaluminium compound and (3) a Lewis acid are contacted in the presence of a non-polar solvent using a particular procedure to produce high 1,4-cis polybutadiene.
BRIEF SUMMARY OF THE INVENTION
In an attempt to develop a catalyst usable in the preparation of high cis polydiene and high catalyst activity without gel formation, the inventors have contrived a novel neodymium carboxylate compound NdHA
4
which has monomeric structure and does not contain water, bases and salts, and its use in the polymerization of diene with halogen and organic metal compounds.
Accordingly, it is an object of the present invention to provide a novel monomeric neodymium carboxylate, NdHA
4
, of a high catalyst activity without gel formation when used in the preparation of polydiene.
It is another object of the present invention to provide a catalyst system comprising the novel monomeric neodymium carboxylate for polymerization of 1,3-budadiene or isoprene.
It is further another object of the present invention to provide a use of the polymerization catalyst in the preparation of polydiene having a very high 1,4-cis content (more than 96%).
To achieve the above objects of the present invention, there is provided a novel monomeric neodymium compound represented by NdHA
4
, wherein A is a carboxylate containing 8 to 20 carbon atoms.
Furthermore, there is provided a diene polymerization catalyst including: (A) a novel monomeric neodymium compound represented by NdHA
4
according to claim
1
; (B) a halogen compound; and (C) an organic metal compound.
DETAILED DESCRIPTION OF THE INVENTION
The novel neodymium compound of the present invention is represented by NdHA
4
wherein A is a carboxylate containing 8 to 20 carbon atoms.
Examples of the carboxylate “A” in the formula may include neodecanoate (versatate), octoate, and naphthenate.
NdHA
4
can be prepared by ligand exchange between neodymium carboxylate or neodymium alkoxide and carboxylic acid in the presence of an organic solvent such as chlorobenzene. Preferably, examples of carboxylic acid may include versatic acid, 2-ethylhexanoic acid, naphthenic acid, and stearic acid.
NdHA
4
is activated in the mixture with a halogen or organic metal compound and used as a polymerization catalyst for polydiene.
NdHA
4
has a monomeric structure satisfying the minimum coordination number of 8 that provides high activity, prevents agglomeration of the neodymium compound and thus reduces gel formation of polydienes in polymerization.
Particularly, NdHA
4
is neutral without coordination with water, bases and salts so as to eliminate gel formation.
More specifically, a novel catalyst system for polymerization of 1,3-butadiene or isoprene is prepared by combining (A) NdHA
4
, (B) halogen compound and (C) organic metal compound.
In regard to the second essential compound (B) used in the catalyst system, examples of the halogen compound may include, if not limited to, aluminum halogen compounds represented by R
1
n
AlX
n-3
wherein R
1
is hydrogen or an alkyl or aryl group containing 1 to 10 carbon atoms, X is halogen, and n is an integer from 1 to 3; and inorganic or organic halogen compounds in which aluminum is completely substituted by boron, silicon, tin or titanium in the aluminum halogen compounds, wherein the organic halogen compounds are preferably alkyl halogen compounds containing 4 to 20 carbon atoms.
Preferably, examples of the organic metal compound as the third essential compound (C) of the catalyst system may include, if not limited to, alkyl aluminum compounds represented by AlR
2
3
; alkyl magnesium compounds represented by MgR
2
2
; alkyl zinc compounds represented by ZnR
2
2
and alkyl lithium compounds represented by LiR
2
wherein R
2
is hydrogen or an alkyl, cycloalkyl, aryl, arylaklyl or alkoxyl group containing 1 to 10 carbon atoms.
More specifically, examples of suitable organic metal compounds may include trimethyl aluminum, triethyl aluminum, tripropyl aluminum, tributyl aluminum, triisobutyl aluminum, trihexyl aluminum, diisobutyl aluminum hydride, dibutyl magnesium, diethyl magnesium, dibutyl zinc, diethyl zinc and n-butyl lithium.
NdHA
4
is mixed with a halogen compound and an organic metal compound, and then activated as a catalyst system for the polymerization of diene in such a manner that diene is subjected to be polymerized in the presence of the catalyst system and a non-polar solvent at a temperature of 0 to 200° C. for 10 minutes to 5 hours.
In polymerization of 1,3-butadiene using NdHA
4
, high cis polybutadiene thus obtained has a very high content (more than 95%) and high catalyst activity (4.0×10
−5
mol Nd/100 g BD) without gel formation.
The catalyst system of the present invention can be prepared by mixing (A) NdHA
4
, (B) halogen compound and (C) organic metal compound under a nitrogen atmosphere and aging the mixture in a non-polar solvent at a temperature of −30 to 60° C. for 5 minutes to 2 hours; or adding the three essential compounds in the order of (B), (C) and (A), (C), (B) and (A), or (A)-(B)-(C) to the reactor containing butadiene and a solvent.
It is desirable that the mole ratio of component (B) to component (A) is 1:1 to 1:20 and that the mole ratio of component (C) to component (A) is 1:10 to 1:200.
The suitable solvent used in polymerization is preferably a non-polar solvent not reactive with the components of the catalyst system. Examples of suitable
Jang Young Chan
Kim A Ju
Kwag Gwang Hoon
Lee Seung Hwon
Davidson Davidson & Kappel LLC
Korea Kumho Petrochemical Co. Ltd.
Rabago R.
Wu David W.
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