Silica gel-supported catalyst component for ethylene...

Details Silica gel-supported catalyst component for ethylene... Silica gel-supported catalyst component for ethylene...

2001-08-22

2003-11-04

Choi, Ling-Siu (Department: 1713)

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

Synthetic resins

Polymers from only ethylenic monomers or processes of...

C526S352000, C526S348000, C526S901000, C526S143000, C526S123100, C502S103000, C502S115000, C502S118000, C502S121000, C502S125000, C502S128000

Reexamination Certificate

active

06642325

ABSTRACT:

FIELD OF THE INVENTION
The present invention relates to a silica gel-supported catalyst component suitable for ethylene (co)polymerization, a catalyst therefrom and its use in ethylene (co)polymerization, in particular in a gas phase fluidized bed process operated in a condensed state.
BACKGROUND OF THE INVENTION
It is well known that microspherical silica gels (having an average particle size of 10 to 100 microns) has been widely applied in catalysts for olefin polymerization as the carrier, especially in catalysts for olefin polymerization by a gas phase process, and silica gels which have been used currently include SYLOPOL 948, SYLOPOL 955 and XPO-2402 manufactured and marketed by Grace Corporation, USA and SD490 manufactured and marketed by Crosfield Corporation, typically having a specific surface area of about 300 m
2
/g or even less. When applied for supporting catalysts, the amount of the active components supported on these silica gels are limited and thus the improvements in catalytic activity are limited. For example, U.S. Pat. Nos. 4,293,673, 4,302,565, 4,302,566 and 4,303,771 disclose a series of catalysts suitable for ethylene polymerization by a gas phase fluidized bed process, in which the above mentioned silica gels are used as the carrier. Up to now, most of such commercially available catalysts are obtained by supporting a magnesium compound, a titanium compound and an electron donor onto SYLOPOL 955 silica gel and when they are used for ethylene polymerization by a gas phase fluidized bed process, the catalytic activity is typically about 3500 g PE/g Cat; however, when they are used in a gas phase fluidized bed process operated in a condensed state, the catalytic activity is substantially lowered due to the shortening of the residence time of the catalysts, thereby leading to an increase in the ash content of the resultant ethylene polymers, which in turn deteriorates the quality of ethylene polymers. Therefore, enhancing the activity of such catalysts is one of the key factors for the improvement in the quality of the ethylene polymers. If, however, only the specific surface area of silica gel is increased, on one hand, the activity of the catalysts when used for olefin polymerization is enhanced to some extent; on the other hand, the pore size of silica gel is decreased due to the increase in its specific surface area, thus other properties such as hydrogen response, copolymerizability of ethylene with other alpha-olefins and the like decrease dramatically (cf. U.S. Pat. No. 3,225,023). Therefore, taking the balance among various properties into account, the currently commercialized silica gel carrier materials for ethylene polymerization by a gas phase process is typically controlled to have a specific surface area of about 300 m
2
/g.
SUMMARY OF THE INVENTION
After extensive and repetitive investigation, the present inventors have found that by employing silica gels having a larger specific surface area and supporting thereon a magnesium compound, a titanium compound and an electron donor compound, as well as a halide promoter, the resultant catalyst has not only a largely enhanced activity when used for olefin polymerization, but also excellent hydrogen response and superior copolymerizability of ethylene with other alpha-olefins. Especially in the gas phase fluidized bed process operated in a condensed state, which represents an advanced process currently, the catalyst according to the present invention shows a good balance among various properties.
The object of the present invention is to provide a highly active silica gel-supported catalyst component suitable for ethylene (co)polymerization, which has overcome the disadvantages associated with the prior silica gel-supported titanium based catalyst, such as low activity and the like.
Another object of the present invention is to provide a catalyst for ethylene (co)polymerization.
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 silica gel-supported catalyst component suitable for ethylene (co)polymerization which is a titanium-containing active component supported on a porous inert carrier material, comprising the reaction product of at least one titanium compound, at least one magnesium compound, at least one halide promoter, and at least one electron donor, wherein said porous inert carrier material is spherical or spheroidal silica gel having an average particle size of 10 to 100 microns, a specific surface area of 300 to 1000 m
2
/g, a pore volume of 2.0 to 5.0 ml/g and an average pore diameter of 5 to 45 nanometers.
In its second aspect, the present invention provides a catalyst comprising the supported catalyst component in accordance with the present invention.
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
The catalyst component in accordance with the present invention is obtained by impregnating a carrier material with the reaction product of at least one titanium compound, at least one magnesium compound and at least one electron donor compound so as to support the reaction product onto the carrier material. It should be particularly noted that the carrier material is selected among spherical or spheroidal silica gels having a larger specific surface area, with dehydrated silica gels being preferred. The hydroxyl content on the surface is typically adjusted by controlling the conditions for heat-activating silica gels Preferably, silica gels have an average particle size of 10 to 100 microns, more preferably 20 to 80 microns, most preferably 30 to 60 microns; a specific surface area of 300 to 1000 m
2
/g, more preferably 400 to 800 m
2
/g, most preferably 600 to 800 m
2
/g; a pore volume of 1.0 to 6.0 ml/g, more preferably 2.0 to 5.0 ml/g; and an average pore diameter of 5 to 45 nanometers, more preferably 10 to 35 nanometers.
In the catalyst component as mentioned above, at least one halide promoter is also added. The halide promoter is a class of compounds represented by general formula F—R
1
[R
2
b
X
(3-b)
] wherein F represents a functional group which is chemically reactive with the organoaluminium compound, the titanium compound or hydroxyl groups on silica gels, such as an aldehyde group, an acyl group, a hydroxyl group, an amino group, an ester group and the like; R
1
represents a divalent C
1
-C
6
aliphatic or aromatic group which is attached to 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 a hydroxyl group, said promoter is a class of halogenated alcohol, specific compound being 2,2,2-trichloroethanol (Cl
3
CCH
2
OH), 2,2-dichloroethanol (Cl
2
CHCH
2
OH), 2-chloroethanol (ClCH
2
CH
2
OH), 1,1-dimethyl-2,2,2-trichloroethanol (Cl
3
CC(CH
3
)
2
OH), 4-chlorobutanol (ClCH
2
CH
2
CH
2
CH
2
OH), para-chlorophenol, 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 an acyl group, 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 as mentioned above, the magnesium compound, the electron donor compound and the titanium compound have been described in U.S. Pat. No. 4,302,565, which is incorporated herein by reference.
In the titanium-containing catalyst component as mentioned above, the magnesium compound, the electron donor compound and the

Affiliated with

Also associated with

Rating

Silica gel-supported catalyst component for ethylene... does not yet have a rating. At this time, there are no reviews or comments for this patent.

If you have personal experience with Silica gel-supported catalyst component for ethylene..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Silica gel-supported catalyst component for ethylene... will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFUS-PAI-O-3127362