Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – Polymers from only ethylenic monomers or processes of...
Reexamination Certificate
2000-12-21
2003-03-25
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...
C526S088000, C526S901000, C526S124200, C526S125100, C526S352000, C502S128000, C502S115000, C502S116000, C502S118000, C502S126000, C502S127000, C502S129000
Reexamination Certificate
active
06538078
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to a highly active titanium based supported catalyst suitable for olefin (co)polymerization, in particular ethylene (co)polymerization by a gas phase process, preparation and use of the same.
BACKGROUND OF THE INVENTION
It is well known that halocarbons have been applied in vanadium based catalysts for olefin polymerization as activity promoters and there are a number of patents involving them. For example, the vanadium based catalysts developed by Union Carbide Corporation have been successfully utilized for the industrial production of polyethylene by a gas phase process, with the key point being the incorporation of halocarbons as activity promoters, resulting in an improvement in the activity of vanadium based catalysts by a factor of 4 to 10 times. Further, U.S. Pat. No. 4,508,842 and CN 87107589A disclose the use of CFCl
3
and the like as promoters; EP 286001 discloses the use of CH
2
Cl
2
or CF
2
ClCFCl
2
as promoters; and U.S. Pat. No. 4,892,853 discloses the use of hexachloropropane or octachloropropane as promoters. In particular, Chinese Patent Application Publication No. CN 1056107A discloses a vanadium based catalyst obtained by supporting a promoter by a chemical bond, wherein the promoter is chemically bonded with said catalyst by reacting a halogenated alcohol, together with hydroxyl groups on the surface of silica, with an organic aluminium compound, thus promoting the activity of the vanadium center.
By investigating the promotion effect of halocarbons on vanadium based catalysts, the researchers from Union Carbide Corporation found out that only CH
2
Cl
2
could promote the activity of the titanium center, and most of halocarbons such as CFCl
3
, CHCl
3
, CCl
4
largely inhibit the titanium center and substantially decrease the catalytic activity[Polymer Material Science and Engineering, pp. 106-107(1991)]. The synthesis for bimodal or broad molecular weight distribution (MWD) polyethylene by using titanium/vanadium bimetallic catalysts is also based on the substantially inhibiting effect of CFCl
3
, CHCl
3
and the like on the titanium center[U.S. Pat. No. 5,442,018].
However, this is not always the case, as demonstrated by the catalysts disclosed in Chinese Patent Application Publication No. CN 1189505A. In said catalyst, halocarbons represented by general formula R
a
CX
(4-a)
(wherein R represents hydrogen, unsubstituted or halogen-substituted alkyl groups having less than 6 carbon atoms, X represents fluorine, chlorine or bromine, and a represents an integer of less than 4) are used. In a suitable molar ratio of the halocarbons to titanium, the catalytic activity of conventional titanium-centered Ziegler-Natta catalysts can be improved by 50 to 100% when used in gas phase polymerization of ethylene. However, since halocarbons are separately added into the polymerization reactor, one obvious disadvantage is the additional step required for adding the halocarbons to the polymerization reactor with its attendant problems of inaccurate feed, mixing problems, contact with the other catalyst components, and the like. After extensive studies made by the present inventors, it has been found out that in the titanium based catalyst with silica as carrier material, the halide promoter according to the present invention becomes a molecularly structural component of the catalyst composition by chemically bonding to silica through chemical reaction between said promoter and hydroxyl groups on the surface of silica, and further, the amounts of the supported promoter can be controlled by regulating the temperature and time for heat-activating the carrier material. Therefore, it is unnecessary to externally add halocarbons into the polymerization reactor, in order to obtain the promotion effect from the halide, and thus the disadvantages associated with the prior arts can be overcome.
SUMMARY OF THE INVENTION
The object of the present invention is to provide a highly active titanium based supported catalyst suitable for ethylene (co)polymerization, which has overcome the disadvantages associated with the prior silica-supported titanium based catalyst and is obtained by supporting a halide promoter onto a carrier material. When the catalyst is used for ethylene polymerization, not only the catalytic activity is largely enhanced, but also the particle morphology of the resulting polymer is further improved and the bulk density is markedly increased.
Another object of the present invention is to provide a process for the preparation of the catalyst in accordance with the present invention.
Still another object of the present invention is to provide the use of the catalyst in accordance with the present invention for olefin (co)polymerization.
In its one aspect, the present invention provides a highly active titanium based supported catalyst suitable for ethylene (co)polymerization, comprising:
A. a supported catalyst component which is a titanium-containing active component supported on an inert carrier material, comprising at least one titanium compound, at least one magnesium compound, at least one halide promoter, at least one electron donor compound and at least one porous inert carrier material; and
B. an alkyl aluminium cocatalyst.
In its second aspect, the present invention provides a process for preparing the supported catalyst component in accordance with the present invention, comprising dissolving the titanium compound and the magnesium compound mentioned above into an electron donor compound, thereby obtaining a mother liquor, and then supporting said compounds onto an inert carrier material by impregnation.
In its third aspect, the present invention relates to the use of the catalyst in accordance with the present invention for olefin (co)polymerization.
DETAILED DESCRIPTION OF THE INVENTION
In the catalyst component A as mentioned above, the magnesium compound, the electron donor compound, the titanium compound and the porous inert carrier material have been described in U.S. Pat. No. 4,302,565, which is incorporated herein by reference.
In the catalyst component A as mentioned above, the halide promoter is a class of compounds represented by general formula F-R
1
[R
2
b
X
(3-b)
], wherein;
F represents an oxygen-containing functional group which is reactive with the organoaluminium compound, the titanium compound or hydroxyl groups, such as aldehyde groups, acyl groups, hydroxyl groups and the like; R
1
represents a divalent C
1
-C
6
aliphatic or aromatic group which is attached to oxygen atom in the functional group F; R
2
represents hydrogen, unsubstituted or halogen-substituted C
1
-C
6
alkyl, C
3
-C
6
cycloalkyl or C
6
-C
10
aromatic groups, b is 0, 1 or 2, and X is F, Cl or Br.
When F represents hydroxyl groups, said promoter is a class of halogenated alcohols, specific compounds being 2,2,2-trichloroethanol, 2,2-dichloroethanol, 2-chloroethanol, 1,1,-dimethyl-2,2,2-trichloroethanol, 4-chlorobutanol, para-chloro-phenol, iso-chlorophenol, ortho-chlorophenol, 2-chlorocyclohexanol and the like, with 2,2,2-trichloroethanol, 2,2-dichloroethanol, 2-chloroethanol and 1,1-dimethyl-2,2,2-trichloroethanol being preferred.
When F represents acyl groups, said promoter is a class of halogenated acyl halide, suitable examples of such compounds being trichloroacetyl chloride, dichloroacetyl chloride, chloroacetyl chloride, o-chlorobenzoyl chloride and 2-chlorocyclohexyl carbonyl chloride, with trichloroacetyl chloride, dichloroacetyl chloride and chloroacetyl chloride being preferred.
In the catalyst component A as mentioned above, preferable titanium compounds are those represented by general formula Ti(OR)
4-n
X
n
, wherein R represents C
1
-C
14
aliphatic hydrocarbon groups, X represents a group selected form the group consisting of F, Cl, Br and mixtures thereof and n is 0, 1 or 2. Suitable examples are selected from the group consisting of titanium tetrachloride, titanium trichloride, titanium tetrabromide, titanium tetraiodide, titanium tetrabutoxide, titanium tetraetho
Luo Hekuan
Tang Ruiguo
Yang Hua
Zhao Qinfang
Birch & Stewart Kolasch & Birch, LLP
China Petro-Chemical Corporation
Choi Ling-Siu
Wu David W.
LandOfFree
Supported catalyst for ethylene (co)polymerization,... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Supported catalyst for ethylene (co)polymerization,..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Supported catalyst for ethylene (co)polymerization,... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3056378