CN112552435A - Double-center supported catalyst and preparation method and application thereof - Google Patents

Double-center supported catalyst and preparation method and application thereof Download PDF

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CN112552435A
CN112552435A CN201910910474.2A CN201910910474A CN112552435A CN 112552435 A CN112552435 A CN 112552435A CN 201910910474 A CN201910910474 A CN 201910910474A CN 112552435 A CN112552435 A CN 112552435A
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vanadium
chromium
catalyst
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solvent
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张瑞
任鹤
王�华
王文燕
王立娟
宋磊
杨国兴
孙彬彬
杨琦
高宇新
和树立
牛娜
邹恩广
李冬霞
马丽
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Petrochina Co Ltd
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    • C08F—MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
    • C08F10/00—Homopolymers and copolymers of unsaturated aliphatic hydrocarbons having only one carbon-to-carbon double bond
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08F—MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
    • C08F110/00—Homopolymers of unsaturated aliphatic hydrocarbons having only one carbon-to-carbon double bond
    • C08F110/02—Ethene
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08F—MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
    • C08F210/00—Copolymers of unsaturated aliphatic hydrocarbons having only one carbon-to-carbon double bond
    • C08F210/16—Copolymers of ethene with alpha-alkenes, e.g. EP rubbers

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Abstract

The invention discloses a double-center supported catalyst and a preparation method and application thereof, wherein the double-center supported catalyst comprises a carrier and an active component, the carrier is an inorganic carrier, the active component comprises a vanadium-containing organic compound and a chromium-containing organic compound, the vanadium-containing organic compound is chemically bonded with the carrier through oxygen, and the chromium-containing organic compound is chemically bonded with the carrier through oxygen; the vanadium-containing organic compound comprises the following structure: v ═ VN‑R1Wherein R is1Is a hydrocarbon group having 1 to 10 carbon atoms; the chromium-containing organic compound comprises the following structure: Cr-R2Wherein R is2Is substituted cyclopentadienyl, indenyl or fluorenyl; the substituents for the cyclopentadienyl, indenyl and fluorenyl groups are aromatic groups having 6 to 20 carbon atoms.

Description

Double-center supported catalyst and preparation method and application thereof
Technical Field
The invention relates to an inorganic carrier supported double-center organic metal composite catalyst, a preparation method of the catalyst and a method for using the catalyst in olefin polymerization.
Background
Polyethylene (PE) resin is a thermoplastic plastic made by homopolymerization of ethylene monomer or copolymerization of ethylene and a small amount of α -olefin, and is one of the most popular plastic products in the world today with the highest yield and consumption, mainly including Low Density Polyethylene (LDPE), Linear Low Density Polyethylene (LLDPE), High Density Polyethylene (HDPE), and some products with special properties. From a consumer structural point of view, the main use of low density polyethylene will still be focused on films, sheet articles and injection molded articles; in consumer structures of high density polyethylene, blow molded and injection molded articles will be the primary application. The high-hardness plastic has the characteristics of low price, excellent chemical insulation, high impact strength and high hardness under low temperature, can be widely applied to industry, agriculture, packaging and daily life, and plays a significant role in the plastic industry.
Currently, the widely used industrial polyethylene catalysts are mainly Ziegler-Natta (Z-N) type catalysts, metallocene catalysts and chromium-based catalysts. Among them, the chromium-based catalyst is favored by the market due to its outstanding contribution to HDPE production and its irreplaceability of the product, producing about 50% of HDPE worldwide.
J.P Hogan and R.L. Bank both reported in patent US2825721 a silica gel supported chromium oxide catalyst, the latter well known Phillips inorganic chromium catalyst. Leonard m. baker and Wayne l. carrick disclose an organochromium polyethylene catalyst, i.e., an S-2 organochromium catalyst from Union Carbide, in US3324101, US3324095 and CA 759121. George L.Karapinka discloses in U.S. Pat. Nos. 3709853 and FR1591425 an organochromium polyethylene catalyst, the S-9 organochromium catalyst by Union Carbide. Although the three catalysts are very similar in structure, there are large differences in the catalytic and polymerization behavior. The Phillips inorganic chromium catalyst has high polymerization activity and short induction period, and the produced polyethylene product has wider molecular weight distribution, higher comonomer insertion amount and higher catalyst efficiency; the S-2 organic chromium catalyst has lower polymerization activity and longer induction period, and the produced polyethylene product has wider molecular weight distribution and higher density; the S-9 organic chromium catalyst has relatively high polymerization activity, short induction period and poor copolymerization, and the produced polyethylene product has narrow molecular weight distribution, high density and good hydrogen regulation sensitivity, can produce various melt index products and can meet different market requirements. For many years, the literature mainly reports more about the modification of Phillips chromium-based catalysts, and the research on the modification of S-2 and S-9 catalysts reports less, particularly the research on the modification of the S-9 catalyst reports less.
Although a number of different polyethylene catalysts already exist, there is still a need in the market for catalysts with new properties and polyethylene products thereof.
Disclosure of Invention
The main object of the present invention is to provide a double-center supported catalyst, a preparation method and an application thereof, wherein the catalyst is used for olefin polymerization, can broaden the molecular weight distribution of high density polyethylene produced by the catalyst and has a bimodal distribution, and can improve the copolymerization content and the distribution of comonomers.
In order to achieve the above object, the present invention provides a dual-center supported catalyst, which comprises a carrier and an active component, wherein the carrier is an inorganic carrier, the active component comprises a vanadium-containing organic compound and a chromium-containing organic compound, the vanadium-containing organic compound is chemically bonded to the carrier through oxygen, and the chromium-containing organic compound is chemically bonded to the carrier through oxygen;
the vanadium-containing organic compound comprises the following structure:
V＝N-R1
wherein R is1Is a substituted or unsubstituted hydrocarbyl group having 1 to 10 carbon atoms;
the chromium-containing organic compound comprises the following structure:
Cr-R2
wherein R is2Is a substituted or unsubstituted cyclopentadienyl, indenyl or fluorenyl;
the substituents of the cyclopentadienyl, indenyl and fluorenyl groups are hydrocarbon groups having 0 to 10 carbon atoms.
The double-center supported catalyst provided by the invention has the following structure that:
Figure BDA0002214368510000031
wherein, R is3、R4、R5、R6And R7Each independently is an aliphatic hydrocarbon group of 0 to 10 carbon atoms;
the substituted indenyl group has the following structure:
Figure BDA0002214368510000032
wherein, R is8、R9、R10、R11、R12、R13And R14Each independently is an aliphatic hydrocarbon group of 0 to 10 carbon atoms;
the substituted fluorenyl group has the following structure:
Figure BDA0002214368510000033
wherein, R is15、R16、R17、R18、R19、R20、R21、R22And R23Each independently an aliphatic hydrocarbon group of 0 to 10 carbon atoms.
The double-center supported catalyst of the invention is characterized in that R is3、R4、R5、R6And R7Each independently is hydrogen, methyl, ethyl, propyl or butyl; the R is8、R9、R10、R11、R12、R13And R14Each independently is hydrogen, methyl, ethyl, propyl or butyl, R15、R16、R17、R18、R19、R20、R21、R22And R23Each independently hydrogen, methyl, ethyl, propyl or butyl.
The double-center supported catalyst of the invention is characterized in that R is1Is substituted or unsubstituted aromatic hydrocarbon radical with 1-10 carbon atoms, and the substituted radical is one or more of halogen, nitro and alkoxy.
The double-center supported catalyst provided by the invention is characterized in that the inorganic carrier is one or more of the group consisting of silicon dioxide, aluminum oxide, titanium dioxide, zirconium oxide, magnesium oxide, calcium oxide and inorganic clay.
The double-center supported catalyst is characterized in that the inorganic carrier is silicon dioxide, and the silicon dioxide is unmodified amorphous silicon dioxide or amorphous porous silica gel modified by Ti, Al or F; the pore volume of the inorganic carrier is 0.5-5.0 cm3The surface area of the inorganic carrier is 50-800 m2/g。
The double-center supported catalyst provided by the invention has the advantages that the total weight of the catalyst is taken as a reference, and the supported amount of the chromium-containing organic compound is 0.01-20 wt% in terms of chromium; the loading amount of the chromium-containing organic compound is calculated by chromium, the loading amount of the vanadium-containing organic compound is calculated by vanadium, and the weight ratio of the loading amount of the vanadium-containing organic compound to the loading amount of the chromium-containing organic compound is 0.1-5: 1.
In order to achieve the above object, the present invention also provides a preparation method of a dual-site supported catalyst, comprising the steps of:
step 1, dipping a carrier into a solution containing a vanadium source, drying and roasting;
step 2, adding the product obtained in the step 1 into a solution of a vanadium organic reagent, and reacting to obtain the catalyst loaded with the vanadium organic compound, wherein the vanadium organic reagent has the following structure:
R1-N＝C＝O
wherein R is1Is a substituted or unsubstituted hydrocarbyl group having 1 to 10 carbon atoms; and
step 3, dipping the catalyst loaded with the vanadium-containing organic compound into the solution of the organic chromium source to obtain a double-center supported catalyst;
the organic chromium source comprises the following structure:
R2'-Cr-R2
wherein R is2And R2' are each independently substituted or unsubstituted cyclopentadienyl, indenyl, or fluorenyl; the substituents of the cyclopentadienyl, indenyl and fluorenyl groups are hydrocarbon groups having 0 to 10 carbon atoms.
The preparation method of the double-center supported catalyst further comprises the step of carrying out pre-reduction treatment on the double-center supported catalyst obtained in the step 3 by using an organic metal cocatalyst.
The preparation method of the double-center supported catalyst is characterized in that the step 2 is carried out in an inert atmosphere or under vacuum.
The preparation method of the double-center supported catalyst comprises the following steps of (1) preparing a vanadium source from water-soluble vanadium-containing salt or water-insoluble vanadium-containing salt; the water-soluble vanadium-containing salt is nitrate, phosphate, sulfate, acetate or metavanadate of vanadium, and the water-insoluble vanadium-containing salt is vanadium bisacetylacetonate oxide, vanadium triisopropoxide, vanadium tripropanolate oxide, vanadium acetylacetonate, vanadium triethoxide, vanadyl chloride or vanadium trisilicide.
The preparation method of the double-center supported catalyst comprises the step of preparing a water-soluble vanadium-containing salt from ammonium hexafluorovanadate, vanadium nitrate, vanadyl oxalate, ammonium metavanadate, vanadyl sulfate oxide (IV) hydrate, vanadium sulfate (III), vanadyl trichloride oxide, sodium orthovanadate, sodium metavanadate or vanadium acetate existing in an acid solution.
The invention relates to a preparation method of a double-center supported catalyst, wherein R is1Is substituted or unsubstituted aromatic hydrocarbon radical with 1-10 carbon atoms, and the substituted radical is one or more of halogen, nitro and alkoxy.
The preparation method of the double-center supported catalyst comprises the step of preparing a double-center supported catalyst, wherein the organic chromium source is one or more of the group consisting of bis (cyclopentadiene) chromium (II), bis (ethylcyclopentadiene) chromium (II), bis (pentamethylcyclopentadiene) chromium (II), bis (tetramethylcyclopentadiene) chromium (II) and bis (isopropylcyclopentadiene) chromium (II).
The preparation method of the double-center supported catalyst comprises the following steps of taking the weight of a carrier as a reference, wherein the addition amount of the organic chromium source is 0.01-20 wt% based on chromium, the addition amount of the vanadium source is calculated based on vanadium, and the ratio of the addition amount of the vanadium source to the addition amount of the organic chromium source is 0.1-5: 1.
In order to achieve the purpose, the invention also provides the application of the double-center supported catalyst in ethylene polymerization reaction.
The invention has the beneficial effects that:
the invention provides a novel high-performance supported chromium-vanadium double-center composite polyethylene catalyst, wherein an organic vanadium active component is added on the basis of an organic chromium S-9 catalyst, so that the molecular weight distribution of a high-density polyethylene produced by the catalyst is widened and has double-peak distribution, the copolymerization content and the distribution of a comonomer can be improved, the amount of the comonomer inserted into a low molecular weight end is reduced, the amount of the comonomer inserted into a high molecular weight end is increased, more tie molecules are easily formed, a polyethylene product with higher performance is developed, and the catalyst also has higher activity.
Drawings
FIG. 1 is a schematic diagram of a vanadium-loaded silica gel calcination procedure.
FIG. 2 is a schematic diagram showing the calcination procedure of the carrier silica gel of comparative example 1.
Detailed Description
The following examples illustrate the invention in detail: the present example is carried out on the premise of the technical scheme of the present invention, and detailed embodiments and processes are given, but the scope of the present invention is not limited to the following examples, and the experimental methods without specific conditions noted in the following examples are generally performed according to conventional conditions.
The invention discloses a double-center supported catalyst, which comprises a carrier and an active component, wherein the carrier is an inorganic carrier, the active component is a vanadium-containing organic compound and a chromium-containing organic compound, the vanadium-containing organic compound is chemically bonded with the carrier through oxygen in a connection mode of the vanadium-containing organic compound and the carrier, and the chromium-containing organic compound is chemically bonded with the carrier through oxygen in a connection mode of the chromium-containing organic compound and the carrier;
the vanadium-containing organic compound comprises the following structure:
V＝N-R1
wherein R is1Is a substituted or unsubstituted hydrocarbyl group having 1 to 10 carbon atoms;
the chromium-containing organic compound comprises the following structure:
Cr-R2
wherein R is2Is substituted cyclopentadienyl, indenyl or fluorenyl;
the substituents for the cyclopentadienyl, indenyl and fluorenyl groups are aromatic groups having 6 to 20 carbon atoms.
The dual-center supported catalyst of the present invention can be represented schematically by the following structure:
Figure BDA0002214368510000061
wherein the substituted cyclopentadienyl has the following structure:
Figure BDA0002214368510000062
wherein R is3、R4、R5、R6And R7At least one of which is an aromatic group having 6 to 20 carbon atoms, preferably one of a substituted or unsubstituted phenyl group and a substituted or unsubstituted naphthyl group, and more preferably a phenyl group or a naphthyl group; the remainder may be hydrogen.
The substituted indenyl group has the following structure:
Figure BDA0002214368510000071
wherein R is8、R9、R10、R11、R12、R13And R14At least one of which is an aromatic group having 6 to 10 carbon atoms, preferably one of a naphthyl group and a substituted or unsubstituted phenyl group, and more preferably a phenyl group or a naphthyl group; the remainder may be hydrogen.
The substituted fluorenyl group has the following structure:
Figure BDA0002214368510000072
wherein R is15、R16、R17、R18、R19、R20、R21、R22And R23At least one of which is an aromatic group having 6 to 10 carbon atoms, preferably one of a naphthyl group and a substituted or unsubstituted phenyl group, and more preferably a phenyl group or a naphthyl group; the remainder may be hydrogen.
Wherein the vanadium-containing organic compound V is N-R1R in (1)1Is a substituted or unsubstituted aromatic hydrocarbon group having 1 to 10 carbon atoms. Examples thereof include phenyl, tolyl, ethylphenyl, propylphenyl, isopropylphenyl, xylyl, benzylchlorophenyl, dichlorophenyl, fluorophenyl, methoxyphenyl and nitrophenyl. P-tolyl, m-tolyl, and the like are preferable.
The inorganic support used in the present invention may be any inorganic support commonly used in the preparation of olefin polymerization catalysts. For example selected from the group consisting of silica, alumina, titania, zirconia, magnesia, calcia, inorganic clays, and combinations thereof; preferred are silica, zirconia and inorganic clays. The inorganic clay may include, for example, montmorillonite and the like. In one embodiment, silica gel, especially amorphous porous silica gel, is preferred, unmodified or modified with Ti, Al, F, or the like. These vectors are well known in the art and may be commercially available or synthesized by known methods. As an example of silica gel, Davison 955 may be mentioned. Wherein, the pore volume of the inorganic carrier is preferably 0.5 to 5.0cm3The surface area of the inorganic carrier is 50-800 m2/g。
In the double-center supported catalyst, the total weight of the catalyst is taken as a reference, and the supported amount of the chromium-containing organic compound is 0.01-20 wt% in terms of chromium; the weight ratio of the loading amount of the organic compound containing vanadium to the loading amount of the organic compound containing chromium is 0.1-5:1, preferably 0.2-4: 1.
The invention also provides a preparation method of the double-center supported catalyst, which comprises the following steps:
step 1, dipping a carrier into a solution containing a vanadium source, drying and roasting;
step 2, adding the product obtained in the step 1 into a solution of a vanadium organic reagent, and reacting to obtain the catalyst loaded with the vanadium organic compound, wherein the vanadium organic reagent has the following structure:
R1-N＝C＝O
wherein R is1Is an aliphatic hydrocarbon group having 1 to 10 carbon atoms; and
step 3, dipping the catalyst loaded with the vanadium-containing organic compound into the solution of the organic chromium source to obtain a double-center supported catalyst;
the organic chromium source comprises the following structure:
R2'-Cr-R2
wherein R is2And R2' are each independently substituted cyclopentadienyl, indenyl, or fluorenyl; the substituents of the cyclopentadienyl, indenyl and fluorenyl are aromatic groups having 6 to 20 carbon atoms.
In one embodiment, the source of vanadium is selected from the group consisting of water soluble vanadium containing salts and water insoluble vanadium containing salts. The water-soluble vanadium-containing salt is selected from nitrate, phosphate, sulfate, acetate and various salts of metavanadate of vanadium; preferred are ammonium hexafluorovanadate, vanadium acetate (present only in the acid solution), vanadium nitrate, vanadyl oxalate, ammonium metavanadate, vanadyl sulfate, vanadium (iv) oxide sulfate hydrate, vanadium (iii) sulfate, vanadium oxide trichloride, sodium orthovanadate, sodium metavanadate, and the like. The water-insoluble vanadium-containing salt is selected from vanadium bisacetylacetonate oxide, vanadium triisopropoxide, vanadium tripropanolate oxide, vanadium acetylacetonate, vanadium triethoxide, vanadyl chloride, vanadium trisilicide, etc. Still more preferably, the vanadium source is selected from vanadium acetylacetonate, vanadium acetate, ammonium metavanadate, ammonium hexafluorovanadate, and the like. The solution containing the vanadium source may be an aqueous solution of the vanadium source, but the present invention is not particularly limited.
In detail, step 1 is: immersing the inorganic carrier into a vanadium source aqueous solution, keeping the temperature between room temperature and 60 ℃ for 1-12 hours, then drying the inorganic carrier at 100-200 ℃ for 1-18 hours, at the moment, blowing drying can be used for accelerating the drying speed, then roasting the inorganic carrier in oxygen or air at 150-1000 ℃ for 1-10 hours, and then cooling, wherein the air is replaced by inert gas such as nitrogen or argon when cooling to 300-400 ℃.
The method for supporting the vanadium source on the inorganic carrier may be any known method by which vanadium can be supported on a carrier. According to one embodiment of the invention, the method of supporting a vanadium source on an inorganic support comprises impregnating a porous inorganic support with an aqueous solution of a vanadium source. According to one embodiment, during the impregnation, stirring, preferably continuous stirring, may be carried out. Generally, the stirring is continued for about 1 to 24 hours, preferably about 2 to 12 hours. According to one embodiment, the vanadium loading is up to 50 wt%, preferably about 0.01 to 20 wt%, based on the weight of vanadium, based on the total weight of the catalyst. The resulting support loaded with the vanadium component is then dried. The drying is generally carried out at a temperature of about room temperature to 200 ℃; for example, at about 15 ℃ to 200 ℃, preferably at about 20 ℃ to 200 ℃, and more preferably at about 100 ℃ to 200 ℃. According to one embodiment, the drying is carried out at about 150 ℃. The drying can also be carried out under forced air drying conditions. The drying is carried out for a period of time not particularly limited, but the drying is usually carried out for about 1 to 18 hours, preferably about 1.5 to 12 hours, more preferably about 2 to 10 hours, for example, about 200 minutes. After the drying is finished, the inorganic carrier loaded with the vanadium component is roasted. The manner in which the calcination is carried out is not particularly limited, but the calcination is preferably carried out in a fluidized bed. According to one embodiment, the firing is generally carried out in two stages, namely a low temperature stage and a high temperature stage. The low temperature stage is typically carried out at about 150 ℃ to 400 ℃. The high temperature stage is typically carried out at about 500 ℃ to 1000 ℃. Without being bound by any theory, the physical water adsorbed in the low temperature stage support is substantially removed, while a portion of the hydroxyl groups on the inorganic support are removed in the high temperature stage. According to one embodiment, the low temperature phase lasts for 1 to 10 hours, preferably 2 to 8 hours. According to another embodiment, the high temperature phase lasts for 1 to 10 hours, preferably 2 to 9 hours, more preferably 3 to 8 hours. According to one embodiment, the low temperature stage is carried out under an inert gas or air atmosphere, preferably under an inert gas atmosphere, such as the inert gases described above. According to one embodiment, the high temperature stage firing is carried out under air or oxygen conditions, preferably under dry air conditions. After the baking and sintering, the resulting inorganic support loaded with vanadium in the form of an inorganic oxide is cooled from the high temperature stage. According to one embodiment, the atmosphere may be changed, for example from air to an inert gas, such as nitrogen, argon, etc., upon cooling to a temperature of 300-400 ℃. According to one embodiment, the cooling is free cooling.
The step 2 is as follows: and (2) immersing the catalyst precursor obtained in the step (1) into an organic agent solution in an inert gas atmosphere, reacting for 1-30 hours at the temperature of room temperature to 200 ℃, and then drying for 1-12 hours at the temperature of 60-200 ℃, wherein the drying speed can also be accelerated by vacuum drying.
Among them, the preferable structure of the organizing agent is: r1-N＝C＝O。R1The hydrocarbon group has 1 to 10 carbon atoms, preferably an aromatic hydrocarbon group having 1 to 10 carbon atoms, more preferably a phenyl group, a tolyl group, an ethylphenyl group, a propylphenyl group, a isopropylphenyl group, a xylyl group, a benzylchlorophenyl group, a dichlorophenyl group, a fluorophenyl group, a methoxyphenyl group, a nitrophenyl group or the like, and further preferably a p-tolyl group, an m-tolyl group or the like.
The above step 2 is a method of organizing the inorganic carrier loaded with vanadium in the form of an inorganic oxide obtained in the step 1. The organizing agent may be the organizing agent described above. Typically, the organic reaction is carried out after the loading of the inorganic vanadium source. In one embodiment, the organic reaction is carried out by placing the inorganic support (e.g., the inorganic support prepared above) loaded with the inorganic vanadium component in a solvent, followed by addition of an organizing agent. The solvent may be any solvent capable of dissolving the organizing agent and supporting it on the inorganic support. The solvent may be an alkane, such as n-pentane, n-hexane, isopentane, n-heptane, n-octane, or the like, or an aromatic hydrocarbon, such as benzene, toluene, xylene, or the like, or any other mixed alkane. According to one embodiment, the solvent is n-octane or toluene. According to one embodiment, the solvent is a solvent after dehydration deoxygenation refining treatment. According to one embodiment, the organic reaction is generally carried out under stirring, preferably with continuous stirring. The time for which the stirring is carried out is not particularly limited as long as the reaction is complete. According to one embodiment, the stirring is carried out for 1 to 36 hours, preferably 4 to 24 hours. According to one embodiment, the organic reaction is carried out under an inert gas atmosphere, such as nitrogen. According to one embodiment, the organic reaction is carried out at a temperature of from room temperature to 200 ℃, for example from room temperature to 160 ℃. According to one embodiment, the ratio of the molar amount of added organizing agent to the molar amount of vanadium in step i) is between 0.1 and 30, preferably between about 0.5 and 20. The drying may be carried out at 30 to 250 ℃, preferably at 60 to 200 ℃. The drying may be carried out for 1 to 12 hours, preferably 2 to 10 hours. According to one embodiment, the drying is carried out under an inert gas atmosphere, for example under an atmosphere of nitrogen, helium, argon, etc., preferably under a nitrogen atmosphere, and the drying process may also be carried out under vacuum conditions. The obtained organic vanadium catalyst matrix is stored under inert gas atmosphere for later use.
And 3, immersing the catalyst precursor obtained in the step 2 into an organic chromium source solution in an inert gas atmosphere, reacting for 1-10 hours at the temperature of room temperature to 100 ℃, adding a solvent, stirring and washing for several times, washing for 0.5-5 hours at the temperature of room temperature to 100 ℃, and drying for 2-8 hours at the temperature of 60-120 ℃, wherein the drying speed can also be accelerated by vacuum drying.
Wherein, the preferable structure of the organic chromium source is as follows: r2'-Cr-R2。R2And R2' are each independently substituted cyclopentadienyl, indenyl, or fluorenyl; the substituents of the cyclopentadienyl, indenyl and fluorenyl are aromatic groups having 6 to 20 carbon atoms. Preferably, the organic chromium source is selected from bis (cyclopentadienyl) chromium (II), bis (ethylcyclopentadienyl) chromium (II), bis (pentamethylcyclopentadienyl) chromium (II), bis (tetramethylcyclopentadienyl) chromium (II) and bis (isopropylcyclopentadienyl) chromium (II), bis (indenyl) chromium (II), bis (fluorenyl) chromium (II), bis (9-methylfluorenyl) chromium (II).
The above step 3 is a method for supporting an organochromium source on the catalyst precursor prepared in step 2. The organic chromium source may be the organic chromium source described above. Generally, the loading of the organic chromium source is performed after the loading of the organic vanadium source. In one embodiment, the loading of the organochromium source is carried out by placing the inorganic support loaded with the organovanadium component (e.g., the inorganic support prepared above) in a solvent and then adding the organochromium source. The solvent may be any solvent capable of dissolving the organochromium source and supporting it on the inorganic support, such as the solvent used in the preparation of the S-9 catalyst. The solvent may be an alkane, such as n-pentane, n-hexane, isopentane, n-heptane, n-octane, or the like, or any other mixed alkane. According to one embodiment, the solvent is n-hexane or n-heptane. According to one embodiment, the solvent is a solvent after dehydration deoxygenation refining treatment. According to one embodiment, the loading of the organochromium source is generally carried out with stirring, preferably with continuous stirring. The time for which the stirring is carried out is not particularly limited as long as the reaction is complete. According to one embodiment, the stirring is carried out for 1 to 24 hours, preferably 2 to 16 hours. According to one embodiment, the loading of the organochromium source is carried out at a temperature of from room temperature to 100 ℃, for example from room temperature to 80 ℃. According to one embodiment, the loading of the organochromium source is carried out under an inert gas atmosphere, such as nitrogen. According to an experimental scheme, after the dipping reaction is completed, the solvent is stirred and washed for several times, and the stirring and washing are carried out for 0.5 to 5 hours at the temperature of between room temperature and 100 ℃, preferably for 0.5 to 2 hours at the temperature of between room temperature and 80 ℃. According to one embodiment, the organic chromium loading is up to 20 wt%, preferably from about 0.01 to 4 wt%, more preferably from about 0.02 to 3 wt% of the total weight of the catalyst, based on the weight of chromium. The drying may be carried out at 30 to 150 ℃, preferably at 60 to 120 ℃. The drying may be carried out for 1 to 12 hours, preferably 2 to 10 hours. According to one embodiment, the drying is carried out under an inert gas atmosphere, for example under an atmosphere of nitrogen, helium, argon, etc., preferably under a nitrogen atmosphere, and the drying process may also be carried out under vacuum conditions. The obtained chromium-vanadium double-center composite catalyst is stored under the inert gas atmosphere for later use.
In summary, the invention uses inorganic compound as carrier, firstly, the vanadium source is dipped on the carrier, and then the carrier is roasted at high temperature to prepare the catalyst parent body loaded with inorganic vanadium; and then adding an organic reagent into the solution containing the catalyst parent to carry out organic reaction on the vanadium, thereby obtaining the catalyst parent loaded with organic vanadium. And finally, adding an organic chromium source into the solution containing the catalyst matrix for loading, thereby preparing the supported chromium-vanadium double-center composite catalyst.
As an example, a specific operation for preparing the catalyst of the present invention comprises:
soaking porous amorphous silica gel in ammonium metavanadate water solution with certain concentration, wherein the vanadium loading is 0.1-10% relative to the total weight of the catalyst (based on the weight of vanadium); after continuously stirring for a certain time (for example, 3 to 8 hours), heating and drying; carrying out high-temperature roasting on the silica gel carrier loaded with ammonium metavanadate in a fluidized bed, wherein physical water in the carrier is removed by roasting in a nitrogen atmosphere at a low-temperature stage (for example, 150-400 ℃), partial hydroxyl on the surface of the silica gel is removed by roasting in dry air at a high-temperature stage (for example, 500-1000 ℃), and the silica gel is kept for a certain time (for example, 3-8 hours) at the high-temperature stage; and naturally cooling, and switching to nitrogen protection when the temperature is cooled to 300-400 ℃ to prepare the catalyst matrix carrying the inorganic vanadium. Then, using the dehydrated, deoxidized and refined octane or toluene as a solvent, oxidizing inorganic vanadium into organic vanadium by using an organic agent p-tolyl isocyanate, and continuously stirring for a certain time (for example, 15 to 25 hours) in a reaction bottle until the reaction is complete; after the reaction is completed, the solvent is evaporated to dryness and protected by nitrogen. Finally, using dehydrated, deoxidized and refined hexane or heptane as a solvent, loading an organic chromium source on the catalyst matrix prepared by the method, and continuously stirring for a certain time (for example, 3-8 hours) in a configuration bottle until the reaction is complete; then stirring and washing the mixture for several times by using the solvent, and washing the mixture for 0.5 to 5 hours at the temperature of between room temperature and 100 ℃; the organic chromium source is loaded with chromium loading amount of 0.01-20% of the total weight of the catalyst (based on the weight of chromium); and finally, drying the finished chromium-vanadium double-center composite catalyst, removing the solvent, and storing under the protection of nitrogen for later use.
According to one aspect of the invention, the preparation method of the supported chromium-vanadium double-center composite catalyst comprises the following steps:
step 1, immersing an inorganic carrier into an aqueous solution of an inorganic vanadium source, then drying, and then roasting at 150-1000 ℃;
and 2, immersing the product obtained in the step 1 into an organic agent solution, and then drying and storing.
And 3, immersing the product obtained in the step 2 into an organic chromium source solution, then stirring, washing and drying, adding an organic metal cocatalyst to carry out pre-reduction treatment on the catalyst, and finally drying and storing.
The organometallic co-catalyst includes any one of or a combination of organoaluminum compounds, organolithium compounds, organoboron compounds, and the like known to those skilled in the art for olefin polymerization. According to one embodiment, the organoaluminum compound used as a cocatalyst can include a trialkylaluminum AlR3Dialkyl aluminum alkoxide AlR2OR, dialkyl aluminium halide AlR2X, aluminoxane, ethyl sesquialuminum chloride, and the like, wherein R is an alkyl group, e.g., having 1 to 12 carbon atoms, e.g., methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, n-pentyl, n-hexyl, n-heptyl, n-octyl, n-nonyl, n-dodecyl, and the like, and X is a halogen, e.g., fluorine, chlorine, bromine, and iodine, preferably chlorine. The aluminoxane may include all reactants of aluminum alkyls such as Methylaluminoxane (MAO) and water. The organoaluminum compound as the cocatalyst may be used aloneOr two or more of them may be used in combination. As specific examples, triethylaluminum, triisobutylaluminum, diethylethoxyaluminum, diethylaluminum monochloride, methylaluminoxane and the like can be mentioned as the aluminum compound. According to one embodiment, the Cr-V dual-active-center catalyst is pre-reduction-activated with an organoaluminum co-catalyst at an al/Cr molar ratio of 0 to 1000, preferably 0 to 100, more preferably 0 to 50, at a temperature of room temperature to 100 ℃, preferably room temperature to 60 ℃, for 0.5 to 20 hours, preferably 0.5 to 10 hours, with stirring, preferably with continuous stirring, and then dried at 60 to 120 ℃ for 2 to 8 hours, under an inert gas atmosphere, such as nitrogen, helium, argon, and the like, preferably under nitrogen, and the drying process may also be performed under vacuum. The obtained chromium-vanadium double-center composite catalyst after pre-reduction activation is stored in inert gas atmosphere for later use.
In summary, the preparation method comprises the steps of using an inorganic compound as a carrier, firstly dipping a vanadium source on the carrier, and then roasting at high temperature to prepare a catalyst matrix loaded with inorganic vanadium; and then adding an organic reagent into the solution containing the catalyst parent to carry out organic reaction on the vanadium, thereby obtaining the catalyst parent loaded with organic vanadium. And finally, adding an organic chromium source into the solution containing the catalyst matrix for loading, thereby preparing the supported chromium-vanadium double-center composite catalyst. Finally, carrying out pre-reduction activation treatment on the catalyst by using an organic metal cocatalyst, and storing the activated supported chromium-vanadium double-center composite catalyst for later use.
As an example, a specific operation for preparing the catalyst of the present invention comprises:
soaking porous amorphous silica gel in ammonium metavanadate aqueous solution with a certain concentration, wherein the vanadium loading is 0.1-10% relative to the total weight of the catalyst (by weight of vanadium); after continuously stirring for a certain time (for example, 3 to 8 hours), heating and drying; carrying out high-temperature roasting on the silica gel carrier loaded with ammonium metavanadate in a fluidized bed, wherein physical water in the carrier is removed by roasting in a nitrogen atmosphere at a low-temperature stage (for example, 150-400 ℃), partial hydroxyl on the surface of the silica gel is removed by roasting in dry air at a high-temperature stage (for example, 500-1000 ℃), and the silica gel is kept for a certain time (for example, 3-8 hours) at the high-temperature stage; and naturally cooling, and switching to nitrogen protection when the temperature is cooled to 300-400 ℃ to prepare the catalyst matrix carrying the inorganic vanadium. Then, using the dehydrated, deoxidized and refined octane or toluene as a solvent, oxidizing inorganic vanadium into organic vanadium by using an organic agent p-tolyl isocyanate, and continuously stirring for a certain time (for example, 15 to 25 hours) in a reaction bottle until the reaction is complete; after the reaction is completed, the solvent is evaporated to dryness and protected by nitrogen. Finally, using dehydrated, deoxidized and refined hexane or heptane as a solvent, loading an organic chromium source on the catalyst matrix prepared by the method, and continuously stirring for a certain time (for example, 3-8 hours) in a configuration bottle until the reaction is complete; then stirring and washing the mixture for several times by using the solvent, and washing the mixture for 0.5 to 5 hours at the temperature of between room temperature and 100 ℃; the organic chromium source loaded chromium loading amount is, for example, 0.01-10% of the total weight of the catalyst (based on the weight of chromium), and the organic chromium source is dried at a certain temperature (for example, 60-120 ℃) for a certain period of time (for example, 2-8 hours), and then the drying speed can be accelerated by vacuum drying. Then adding an organic metal cocatalyst (such as triethyl aluminum, triisobutyl aluminum, ethoxy diethyl aluminum, chloro diethyl aluminum, methyl aluminoxane and the like) to carry out pre-reduction activation treatment on the catalyst, and then drying at 60-120 ℃ for 2-8 hours, wherein the drying is carried out under an inert gas atmosphere, such as nitrogen, helium, argon and the like, preferably under a nitrogen atmosphere, and the drying process can also be carried out under a vacuum condition. The obtained chromium-vanadium double-center composite catalyst after pre-reduction activation is stored in inert gas atmosphere for later use.
The supported chromium-vanadium double-center composite catalyst (comprising the chromium-vanadium double-center composite catalyst which is pre-reduced and activated by the organic metal cocatalyst) can be used for producing ethylene homopolymer and ethylene/alpha-olefin copolymer. An organometallic cocatalyst, hydrogen, etc. may be further added as necessary during the polymerization.
Thus, according to another aspect of the present invention, there is provided a process for producing ethylene homopolymers and ethylene/α -olefin copolymers, in particular olefin polymers having a broad molecular weight distribution (partly bimodal), using the supported chromium-vanadium double-site composite catalyst of the present invention.
In the polymerization, the olefin used for the polymerization generally contains ethylene as a polymerization monomer. In one embodiment, the olefin used for the polymerization further comprises a comonomer. The comonomer may be an alpha-olefin having 3 to 20 carbon atoms, such as propylene, 1-butene, 1-pentene, 1-hexene, 1-heptene, 1-octene, 1-nonene, 1-decene, 1-dodecene, 4-methyl-1-pentene, 4-methyl-1-hexene, etc.; these may be used alone or in combination of two or more. The comonomers are preferably 1-butene, 1-hexene, 1-octene and 1-decene. When present, the amount of comonomer is generally in the range of from 0 to 30 vol% (volume concentration of comonomer at the time of polymerization).
An organometallic co-catalyst, such as described above, can be added to the polymerization system as needed during the polymerization process, and according to one embodiment, typically includes an organoaluminum compound. Aluminum compounds used as cocatalysts are well known. The aluminum compound may include trialkylaluminum AlR3Dialkyl aluminum alkoxide AlR2OR, dialkyl aluminium halide AlR2X, aluminoxane and the like, wherein R is an alkyl group, e.g., having 1 to 12 carbon atoms, e.g., methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, n-pentyl, n-hexyl, n-heptyl, n-octyl, n-nonyl, n-dodecyl and the like, and X is a halogen, e.g., fluorine, chlorine, bromine and iodine, preferably chlorine. The alumoxane may include the reaction product of various aluminum alkyls such as Methylalumoxane (MAO) and water. The aluminum compound as the co-catalyst may be used alone or in combination of two or more. As specific examples, mention may be made of triethylaluminum, triisobutylaluminum, ethoxydiethylaluminum, monochlorodiethylaluminum, methylaluminoxane and the like.
The organometallic aluminium compound is generally used in an amount of 0 to 1000 moles per mole of chromium, preferably 0 to 200 moles per mole of chromium, and more preferably 0 to 50 moles per mole of chromium, based on aluminium.
The polymerization reaction may include a molecular weight regulator, which may be hydrogen, as an example.
The above-mentioned method for producing a polymer of the present invention is not particularly limited in terms of the method for polymerizing the same. The above-mentioned method for producing olefin polymers using the chromium vanadium dual-site composite catalyst of the present invention may include a gas phase polymerization method, a slurry polymerization method, a suspension polymerization method, a bulk polymerization method, a solution polymerization method, etc., and combinations thereof. As understood by those skilled in the art, the method for producing olefin polymers using the chromium vanadium dual-site composite catalyst of the present invention is not particularly limited, and may be carried out using conventional embodiments and polymerization conditions of gas phase polymerization process, slurry polymerization process, suspension polymerization process, bulk polymerization process, solution polymerization process, etc., and combinations thereof, and the like, which are known in the art.
In one embodiment, the polymerization is initiated using a slurry polymerization process comprising feeding ethylene to a reaction vessel, then adding solvent and cocatalyst (aluminum compound) and optionally hydrogen and comonomer, and finally adding the chromium vanadium dual-site composite catalyst of the present invention.
The solvent used in the above slurry polymerization is generally any solvent known in the art for olefin polymerization. The solvent may be an alkane having 3 to 20 carbon atoms, such as propane, n-butane, isobutane, n-pentane, isopentane, neopentane, n-hexane, cyclohexane, n-heptane, n-octane, etc.; these solvents may be used alone or may be used in combination of two or more. The solvent is preferably isobutane, isopentane, n-hexane, cyclohexane, n-heptane, etc.
In one embodiment, the polymerization is carried out using a conventional slurry polymerization process, as follows: firstly, heating a polymerization reaction kettle in vacuum (100 ℃), then replacing the polymerization reaction kettle with high-purity nitrogen, repeatedly operating for three times, then replacing the polymerization reaction kettle with a small amount of ethylene monomer once, and finally filling the reaction kettle with ethylene to a micro-positive pressure (0.12 MPa); adding a refined solvent subjected to dehydration and deoxidation treatment into a reaction kettle, taking a certain amount of alkyl aluminum as a cocatalyst, respectively adding a certain amount of hydrogen and a comonomer in a hydrogen blending copolymerization experiment, and finally adding the catalyst of the invention to start a polymerization reaction; the instantaneous consumption of monomer ethylene is collected on line in the reaction process (by connecting a high-precision ethylene mass flow meter with a computer) and recorded by the computer, and the reaction is stopped after the reaction is carried out for a certain time (for example, 1 hour) at a certain temperature (for example, 35 ℃ to 100 ℃); the polymer was washed, dried in vacuo, weighed and analyzed.
The catalyst of the present invention can produce ethylene homopolymers and ethylene/alpha-olefin copolymers (part of the product having a bimodal distribution) having a broad molecular weight distribution (MWD ═ 10 to 60) in a single reactor or a combination of reactors. By using the catalyst of the present invention, the molecular weight and distribution of ethylene homopolymer and ethylene and α -olefin copolymer and the comonomer content and distribution thereof can be conveniently and easily adjusted by changing the amount of co-catalyst used, polymerization temperature, molecular weight regulator and the like, so that a polymer product having desired properties can be conveniently and easily obtained.
The present invention is explained in more detail with reference to the following examples, which do not limit the scope of the present invention.
The silica gel employed in the examples was commercially available as Davison 955.
Various polymer properties in the examples were measured according to the following methods:
high temperature gel chromatography (HT-GPC)
Weight average molecular weight and molecular weight distribution were determined by high temperature gel chromatography: in this experiment, the molecular weight of polyethylene and the molecular weight distribution thereof were measured by means of a PL-220 type high temperature gel permeation chromatograph (Polymer Laboratories, Inc.). In the experiment, 1,2, 4-trichlorobenzene is used as a solvent and is measured at 160 ℃. And processing data by adopting a universal correction method with narrow-distribution polystyrene as a standard sample.
Example 1:
10g of silica gel (pore volume of 1.5-1.7 cm)3A surface area of 250 to 300 m/g2Per g) was impregnated at 40 ℃ in an aqueous ammonium metavanadate solution with a vanadium loading (in terms of the mass of V) of 0.84%. After continuously stirring for 5 hours, the temperature is raised to 120 ℃ in the airDrying for 12 hours, then roasting the silica gel carrier impregnated with the ammonium metavanadate at high temperature in a fluidized bed, and finally naturally cooling the sample under the protection of nitrogen. The temperature control process of the high-temperature roasting and then cooling is shown in figure 1. Then, toluene after dehydration, deoxidation and purification was used as a solvent to organize the vanadium source by an organizing agent to tolyl isocyanate, and the mixture was refluxed and continuously stirred in a configuration bottle at 120 ℃ for 20 hours under a nitrogen atmosphere until the reaction was completed, and the molar ratio of the organizing agent to vanadium was 1: 1. Next, the mixture was dried at 120 ℃ for 4 hours under vacuum to remove the solvent and stored under nitrogen. Finally, the organic chromium source bis (indenyl) chromium (II) was supported on the catalyst precursor obtained by the above method using dehydrated deoxygenated purified hexane as a solvent, and the reaction was continuously stirred in a flask at 45 ℃ under a nitrogen atmosphere for 6 hours until completion of the reaction. And then washed several times with hexane solvent with stirring. The chromium loading (by mass of Cr) was 1.71%. And finally, drying the finished chromium-vanadium double-center composite catalyst for 5 hours at 80 ℃ in a nitrogen atmosphere to remove the solvent, and then storing the catalyst under the protection of nitrogen for later use.
Example 2:
10g of silica gel (pore volume of 1.5-1.7 cm)3A surface area of 250 to 300 m/g2Per g) was impregnated at 40 ℃ in an aqueous ammonium metavanadate solution with a vanadium loading (in terms of the mass of V) of 1.68%. Continuously stirring for 5 hours, heating to 120 ℃, drying in air for 12 hours, then roasting the silica gel carrier impregnated with ammonium metavanadate at high temperature in a fluidized bed, and finally naturally cooling the sample under the protection of nitrogen. The temperature control process of the high-temperature roasting and then cooling is shown in figure 1. Then, toluene after dehydration, deoxidation and purification was used as a solvent to organize the vanadium source by an organizing agent to tolyl isocyanate, and the mixture was refluxed and continuously stirred in a configuration bottle at 120 ℃ for 20 hours under a nitrogen atmosphere until the reaction was completed, and the molar ratio of the organizing agent to vanadium was 1: 1. Next, the mixture was dried at 120 ℃ for 4 hours under vacuum to remove the solvent and stored under nitrogen. Finally, the organic chromium source bis (indenyl) chromium (II) is supported on the catalyst precursor prepared by the method using dehydrated deoxygenated refined hexane as solventThe mixture was stirred continuously in a nitrogen atmosphere at 45 ℃ for 6 hours in a preparation flask until the reaction was complete. And then washed several times with hexane solvent with stirring. The chromium loading (by mass of Cr) was 1.71%. And finally, drying the finished chromium-vanadium double-center composite catalyst for 5 hours at 80 ℃ in a nitrogen atmosphere to remove the solvent, and then storing the catalyst under the protection of nitrogen for later use.
Example 3:
10g of silica gel (pore volume of 1.5-1.7 cm)3A surface area of 250 to 300 m/g2Per g) was impregnated at 40 ℃ in an aqueous ammonium metavanadate solution with a vanadium loading (in terms of the mass of V) of 3.36%. Continuously stirring for 5 hours, heating to 120 ℃, drying in air for 12 hours, then roasting the silica gel carrier impregnated with ammonium metavanadate at high temperature in a fluidized bed, and finally naturally cooling the sample under the protection of nitrogen. The temperature control process of the high-temperature roasting and then cooling is shown in figure 1. Then, toluene after dehydration, deoxidation and purification was used as a solvent to organize the vanadium source by an organizing agent to tolyl isocyanate, and the mixture was refluxed and continuously stirred in a configuration bottle at 120 ℃ for 20 hours under a nitrogen atmosphere until the reaction was completed, and the molar ratio of the organizing agent to vanadium was 1: 1. Next, the mixture was dried at 120 ℃ for 4 hours under vacuum to remove the solvent and stored under nitrogen. Finally, the organic chromium source bis (indenyl) chromium (II) was supported on the catalyst precursor obtained by the above method using dehydrated deoxygenated purified hexane as a solvent, and the reaction was continuously stirred in a flask at 45 ℃ under a nitrogen atmosphere for 6 hours until completion of the reaction. And then washed several times with hexane solvent with stirring. The chromium loading (by mass of Cr) was 1.71%. And finally, drying the finished chromium-vanadium double-center composite catalyst for 5 hours at 80 ℃ in a nitrogen atmosphere to remove the solvent, and then storing the catalyst under the protection of nitrogen for later use.
Example 4:
10g of silica gel (pore volume of 1.5-1.7 cm)3A surface area of 250 to 300 m/g2Per g) was impregnated at 60 ℃ in an aqueous ammonium metavanadate solution with a vanadium loading (in terms of the mass of V) of 1.68%. After continuously stirring for 5 hours, heating to 120 ℃, drying in the air for 12 hours, and then putting the silica gel carrier soaked with ammonium metavanadate inAnd (4) carrying out high-temperature roasting in the fluidized bed, and finally, naturally cooling the sample under the protection of nitrogen. The temperature control process of the high-temperature roasting and then cooling is shown in figure 1. Then, toluene after dehydration, deoxidation and purification was used as a solvent to organize the vanadium source by an organizing agent to tolyl isocyanate, and the mixture was refluxed and continuously stirred in a configuration bottle at 120 ℃ for 20 hours under a nitrogen atmosphere until the reaction was completed, and the molar ratio of the organizing agent to vanadium was 1: 1. Next, the mixture was dried at 120 ℃ for 4 hours under vacuum to remove the solvent and stored under nitrogen. Finally, the organic chromium source bis (indenyl) chromium (II) was supported on the catalyst precursor obtained by the above method using dehydrated deoxygenated purified hexane as a solvent, and the reaction was continuously stirred in a flask at 45 ℃ under a nitrogen atmosphere for 6 hours until completion of the reaction. And then washed several times with hexane solvent with stirring. The chromium loading (by mass of Cr) was 1.71%. And finally, drying the finished chromium-vanadium double-center composite catalyst for 5 hours at 80 ℃ in a nitrogen atmosphere to remove the solvent, and then storing the catalyst under the protection of nitrogen for later use.
Example 5:
10g of silica gel (pore volume of 1.5-1.7 cm)3A surface area of 250 to 300 m/g2Per g) was impregnated at 40 ℃ in an aqueous ammonium metavanadate solution with a vanadium loading (in terms of the mass of V) of 1.68%. Continuously stirring for 10 hours, heating to 120 ℃, drying in air for 12 hours, then roasting the silica gel carrier impregnated with ammonium metavanadate at high temperature in a fluidized bed, and finally naturally cooling the sample under the protection of nitrogen. The temperature control process of the high-temperature roasting and then cooling is shown in figure 1. Then, toluene after dehydration, deoxidation and purification was used as a solvent to organize the vanadium source by an organizing agent to tolyl isocyanate, and the mixture was refluxed and continuously stirred in a configuration bottle at 120 ℃ for 20 hours under a nitrogen atmosphere until the reaction was completed, and the molar ratio of the organizing agent to vanadium was 1: 1. Next, the mixture was dried at 120 ℃ for 4 hours under vacuum to remove the solvent and stored under nitrogen. Finally, the organic chromium source bis (indenyl) chromium (II) was supported on the catalyst precursor obtained by the above method using dehydrated deoxygenated purified hexane as a solvent, and the mixture was continuously stirred in a flask at 45 ℃ under a nitrogen atmosphere for 6 hours until the reaction mixture was cooled to room temperatureThe reaction was complete. And then washed several times with hexane solvent with stirring. The chromium loading (by mass of Cr) was 1.71%. And finally, drying the finished chromium-vanadium double-center composite catalyst for 5 hours at 80 ℃ in a nitrogen atmosphere to remove the solvent, and then storing the catalyst under the protection of nitrogen for later use.
Example 6:
10g of silica gel (pore volume of 1.5-1.7 cm)3A surface area of 250 to 300 m/g2Per g) was impregnated at 40 ℃ in an aqueous ammonium metavanadate solution with a vanadium loading (in terms of the mass of V) of 1.68%. Continuously stirring for 5 hours, heating to 120 ℃, drying in air for 12 hours, then roasting the silica gel carrier impregnated with ammonium metavanadate at high temperature in a fluidized bed, and finally naturally cooling the sample under the protection of nitrogen. The temperature control process of the high-temperature roasting and then cooling is shown in figure 1. Then, toluene after dehydration, deoxidation and purification was used as a solvent to organize the vanadium source with toluene isocyanate as an organizing agent, and the mixture was refluxed and continuously stirred in a nitrogen atmosphere at 80 ℃ in a configuration bottle for 20 hours until the reaction was completed, and the molar ratio of the organizing agent to vanadium was 1: 1. Next, the mixture was dried at 120 ℃ for 4 hours under vacuum to remove the solvent and stored under nitrogen. Finally, the organic chromium source bis (indenyl) chromium (II) was supported on the catalyst precursor obtained by the above method using dehydrated deoxygenated purified hexane as a solvent, and the reaction was continuously stirred in a flask at 45 ℃ under a nitrogen atmosphere for 6 hours until completion of the reaction. And then washed several times with hexane solvent with stirring. The chromium loading (by mass of Cr) was 1.71%. And finally, drying the finished chromium-vanadium double-center composite catalyst for 5 hours at 80 ℃ in a nitrogen atmosphere to remove the solvent, and then storing the catalyst under the protection of nitrogen for later use.
Example 7:
10g of zirconium oxide were impregnated at 40 ℃ in an aqueous ammonium metavanadate solution with a vanadium loading (in terms of the mass of V) of 1.68%. Continuously stirring for 5 hours, heating to 120 ℃, drying in air for 12 hours, then roasting the silica gel carrier impregnated with ammonium metavanadate at high temperature in a fluidized bed, and finally naturally cooling the sample under the protection of nitrogen. The temperature control process of the high-temperature roasting and then cooling is shown in figure 1. Then, toluene after dehydration, deoxidation and purification was used as a solvent to organize the vanadium source with toluene isocyanate as an organizing agent, and the mixture was refluxed and continuously stirred in a nitrogen atmosphere at 80 ℃ in a configuration bottle for 20 hours until the reaction was completed, and the molar ratio of the organizing agent to vanadium was 1: 1. Next, the mixture was dried at 120 ℃ for 4 hours under vacuum to remove the solvent and stored under nitrogen. Finally, the organic chromium source bis (indenyl) chromium (II) was supported on the catalyst precursor obtained by the above method using dehydrated deoxygenated purified hexane as a solvent, and the reaction was continuously stirred in a flask at 45 ℃ under a nitrogen atmosphere for 6 hours until completion of the reaction. And then washed several times with hexane solvent with stirring. The chromium loading (by mass of Cr) was 1.71%. And finally, drying the finished chromium-vanadium double-center composite catalyst for 5 hours at 80 ℃ in a nitrogen atmosphere to remove the solvent, and then storing the catalyst under the protection of nitrogen for later use.
Example 8:
10g of inorganic clay was impregnated at 40 ℃ in an aqueous ammonium metavanadate solution with a vanadium loading (in terms of the mass of V) of 1.68%. Continuously stirring for 5 hours, heating to 120 ℃, drying in air for 12 hours, then roasting the silica gel carrier impregnated with ammonium metavanadate at high temperature in a fluidized bed, and finally naturally cooling the sample under the protection of nitrogen. The temperature control process of the high-temperature roasting and then cooling is shown in figure 1. Then, toluene after dehydration, deoxidation and purification was used as a solvent to organize the vanadium source with toluene isocyanate as an organizing agent, and the mixture was refluxed and continuously stirred in a nitrogen atmosphere at 80 ℃ in a configuration bottle for 20 hours until the reaction was completed, and the molar ratio of the organizing agent to vanadium was 1: 1. Next, the mixture was dried at 120 ℃ for 4 hours under vacuum to remove the solvent and stored under nitrogen. Finally, the organic chromium source bis (indenyl) chromium (II) was supported on the catalyst precursor obtained by the above method using dehydrated deoxygenated purified hexane as a solvent, and the reaction was continuously stirred in a flask at 45 ℃ under a nitrogen atmosphere for 6 hours until completion of the reaction. And then washed several times with hexane solvent with stirring. The chromium loading (by mass of Cr) was 1.71%. And finally, drying the finished chromium-vanadium double-center composite catalyst for 5 hours at 80 ℃ in a nitrogen atmosphere to remove the solvent, and then storing the catalyst under the protection of nitrogen for later use.
Example 9:
10g of silica gel (pore volume of 1.5-1.7 cm)3A surface area of 250 to 300 m/g2Per g) was impregnated at 40 ℃ in an aqueous ammonium metavanadate solution with a vanadium loading (in terms of the mass of V) of 1.68%. Continuously stirring for 5 hours, heating to 120 ℃, drying in air for 12 hours, then roasting the silica gel carrier impregnated with ammonium metavanadate at high temperature in a fluidized bed, and finally naturally cooling the sample under the protection of nitrogen. The temperature control process of the high-temperature roasting and then cooling is shown in figure 1. Then, toluene after dehydration, deoxidation and purification was used as a solvent to organize the vanadium source with toluene isocyanate as an organizing agent, and the mixture was refluxed and continuously stirred in a nitrogen atmosphere at 80 ℃ in a configuration bottle for 20 hours until the reaction was completed, and the molar ratio of the organizing agent to vanadium was 1: 1. Next, the mixture was dried at 120 ℃ for 4 hours under vacuum to remove the solvent and stored under nitrogen. Finally, the hexane after dehydration, deoxidation and refining is used as a solvent, organic chromium source bis (tetramethylcyclopentadiene) chromium (II) is loaded on the catalyst parent body prepared by the method, and the mixture is continuously stirred for 6 hours in a nitrogen atmosphere at 45 ℃ in a configuration bottle until the reaction is completed. And then washed several times with hexane solvent with stirring. The chromium loading (by mass of Cr) was 1.71%. And finally, drying the finished chromium-vanadium double-center composite catalyst for 5 hours at 80 ℃ in a nitrogen atmosphere to remove the solvent, and then storing the catalyst under the protection of nitrogen for later use.
Example 10:
10g of silica gel (pore volume of 1.5-1.7 cm)3A surface area of 250 to 300 m/g2Per g) was impregnated at 40 ℃ in an aqueous ammonium metavanadate solution with a vanadium loading (in terms of the mass of V) of 1.68%. Continuously stirring for 5 hours, heating to 120 ℃, drying in air for 12 hours, then roasting the silica gel carrier impregnated with ammonium metavanadate at high temperature in a fluidized bed, and finally naturally cooling the sample under the protection of nitrogen. The temperature control process of the high-temperature roasting and then cooling is shown in figure 1. Then, toluene after dehydration, deoxidation and purification is used as a solvent, and toluene isocyanate is used for organizing a vanadium source by an organizing agentReflux was carried out at 120 ℃ under nitrogen atmosphere in a configuration flask and stirring was continued for 10 hours until the reaction was complete, the molar ratio of the organizing agent to vanadium being 1: 1. Next, the mixture was dried at 120 ℃ for 4 hours under vacuum to remove the solvent and stored under nitrogen. Finally, the organic chromium source bis (indenyl) chromium (II) was supported on the catalyst precursor obtained by the above method using dehydrated deoxygenated purified hexane as a solvent, and the reaction was continuously stirred in a flask at 45 ℃ under a nitrogen atmosphere for 6 hours until completion of the reaction. And then washed several times with hexane solvent with stirring. The chromium loading (by mass of Cr) was 1.71%. And finally, drying the finished chromium-vanadium double-center composite catalyst for 5 hours at 80 ℃ in a nitrogen atmosphere to remove the solvent, and then storing the catalyst under the protection of nitrogen for later use.
Example 11:
10g of silica gel (pore volume of 1.5-1.7 cm)3A surface area of 250 to 300 m/g2Per g) was impregnated at 40 ℃ in an aqueous ammonium metavanadate solution with a vanadium loading (in terms of the mass of V) of 1.68%. Continuously stirring for 5 hours, heating to 120 ℃, drying in air for 12 hours, then roasting the silica gel carrier impregnated with ammonium metavanadate at high temperature in a fluidized bed, and finally naturally cooling the sample under the protection of nitrogen. The temperature control process of the high-temperature roasting and then cooling is shown in figure 1. Then, toluene after dehydration, deoxidation and purification was used as a solvent to organize the vanadium source by an organizing agent to tolyl isocyanate, and the mixture was refluxed and continuously stirred in a configuration bottle at 120 ℃ for 20 hours under a nitrogen atmosphere until the reaction was completed, and the molar ratio of the organizing agent to vanadium was 1: 1. Next, the mixture was dried at 120 ℃ for 4 hours under vacuum to remove the solvent and stored under nitrogen. Finally, the organic chromium source bis (indenyl) chromium (II) was supported on the catalyst precursor obtained by the above method using dehydrated deoxygenated purified hexane as a solvent, and the reaction was continuously stirred in a flask at 45 ℃ under a nitrogen atmosphere for 10 hours until completion of the reaction. And then washed several times with hexane solvent with stirring. The chromium loading (by mass of Cr) was 1.71%. And finally, drying the finished chromium-vanadium double-center composite catalyst for 5 hours at 80 ℃ in a nitrogen atmosphere to remove the solvent, and then storing the catalyst under the protection of nitrogen for later use.
Example 12:
10g of silica gel (pore volume of 1.5-1.7 cm)3A surface area of 250 to 300 m/g2Per g) was impregnated at 40 ℃ in an aqueous ammonium metavanadate solution with a vanadium loading (in terms of the mass of V) of 1.68%. Continuously stirring for 5 hours, heating to 120 ℃, drying in air for 12 hours, then roasting the silica gel carrier impregnated with ammonium metavanadate at high temperature in a fluidized bed, and finally naturally cooling the sample under the protection of nitrogen. The temperature control process of the high-temperature roasting and then cooling is shown in figure 1. Then, toluene after dehydration, deoxidation and purification was used as a solvent to organize the vanadium source by an organizing agent to tolyl isocyanate, and the mixture was refluxed and continuously stirred in a configuration bottle at 120 ℃ for 20 hours under a nitrogen atmosphere until the reaction was completed, and the molar ratio of the organizing agent to vanadium was 1: 1. Next, the mixture was dried at 120 ℃ for 4 hours under vacuum to remove the solvent and stored under nitrogen. Finally, the organic chromium source bis (indenyl) chromium (II) was supported on the catalyst precursor obtained by the above method using dehydrated deoxygenated purified hexane as a solvent, and the reaction was continuously stirred in a flask at 60 ℃ under a nitrogen atmosphere for 6 hours until completion of the reaction. And then washed several times with hexane solvent with stirring. The chromium loading (by mass of Cr) was 1.71%. And finally, drying the finished chromium-vanadium double-center composite catalyst for 5 hours at 80 ℃ in a nitrogen atmosphere to remove the solvent, and then storing the catalyst under the protection of nitrogen for later use.
Example 13:
10g of silica gel (pore volume of 1.5-1.7 cm)3A surface area of 250 to 300 m/g2Per g) was impregnated at 40 ℃ in an aqueous ammonium metavanadate solution with a vanadium loading (in terms of the mass of V) of 1.68%. Continuously stirring for 5 hours, heating to 120 ℃, drying in air for 12 hours, then roasting the silica gel carrier impregnated with ammonium metavanadate at high temperature in a fluidized bed, and finally naturally cooling the sample under the protection of nitrogen. The temperature control process of the high-temperature roasting and then cooling is shown in figure 1. Then, the toluene after dehydration, deoxidation and purification was used as a solvent to organize the vanadium source by an organizing agent with tolyl isocyanate, and the toluene was refluxed and continuously stirred in a setting flask at 120 ℃ under a nitrogen atmosphere20 hours until the reaction is complete, the molar ratio of the organizing agent to vanadium is 1: 1. Next, the mixture was dried at 120 ℃ for 4 hours under vacuum to remove the solvent and stored under nitrogen. Finally, the organic chromium source bis (indenyl) chromium (II) was supported on the catalyst precursor obtained by the above method using dehydrated deoxygenated purified heptane as a solvent, and the reaction was continued for 6 hours under nitrogen atmosphere at 45 ℃ in a flask until completion of the reaction. And then washed with heptane solvent with stirring several times. The chromium loading (by mass of Cr) was 1.71%. And finally, drying the finished chromium-vanadium double-center composite catalyst for 5 hours at 80 ℃ in a nitrogen atmosphere to remove the solvent, and then storing the catalyst under the protection of nitrogen for later use.
Example 14:
10g of silica gel (pore volume of 1.5-1.7 cm)3A surface area of 250 to 300 m/g2And/g) was impregnated with an aqueous solution of vanadium acetylacetonate at a concentration of 40 ℃ and a vanadium loading (in terms of the mass of V) of 1.68%. After continuously stirring for 5 hours, heating to 120 ℃, drying in the air for 12 hours, then roasting the silica gel carrier impregnated with vanadium acetylacetonate in a fluidized bed at high temperature, and finally naturally cooling the sample under the protection of nitrogen. The temperature control process of the high-temperature roasting and then cooling is shown in figure 1. Then, toluene after dehydration, deoxidation and purification was used as a solvent to organize the vanadium source by an organizing agent to tolyl isocyanate, and the mixture was refluxed and continuously stirred in a configuration bottle at 120 ℃ for 20 hours under a nitrogen atmosphere until the reaction was completed, and the molar ratio of the organizing agent to vanadium was 1: 1. Next, the mixture was dried at 120 ℃ for 4 hours under vacuum to remove the solvent and stored under nitrogen. Finally, the organic chromium source bis (indenyl) chromium (II) was supported on the catalyst precursor obtained by the above method using dehydrated deoxygenated purified hexane as a solvent, and the reaction was continuously stirred in a flask at 45 ℃ under a nitrogen atmosphere for 6 hours until completion of the reaction. And then washed several times with hexane solvent with stirring. The chromium loading (by mass of Cr) was 1.71%. And finally, drying the finished chromium-vanadium double-center composite catalyst for 5 hours at 80 ℃ in a nitrogen atmosphere to remove the solvent, and then storing the catalyst under the protection of nitrogen for later use.
Example 15:
10g of silica gel (pore volume of 1.5-1.7 cm)3A surface area of 250 to 300 m/g2Per g) was impregnated at 40 ℃ in an aqueous solution of vanadium acetate with a vanadium loading (by mass of V) of 1.68%. Continuously stirring for 5 hours, heating to 120 ℃, drying in air for 12 hours, then roasting the silica gel carrier impregnated with vanadium acetate at high temperature in a fluidized bed, and finally naturally cooling the sample under the protection of nitrogen. The temperature control process of the high-temperature roasting and then cooling is shown in figure 1. Then, toluene after dehydration, deoxidation and purification was used as a solvent to organize the vanadium source by an organizing agent to tolyl isocyanate, and the mixture was refluxed and continuously stirred in a configuration bottle at 120 ℃ for 20 hours under a nitrogen atmosphere until the reaction was completed, and the molar ratio of the organizing agent to vanadium was 1: 1. Next, the mixture was dried at 120 ℃ for 4 hours under vacuum to remove the solvent and stored under nitrogen. Finally, the organic chromium source bis (indenyl) chromium (II) was supported on the catalyst precursor obtained by the above method using dehydrated deoxygenated purified hexane as a solvent, and the reaction was continuously stirred in a flask at 45 ℃ under a nitrogen atmosphere for 6 hours until completion of the reaction. And then washed several times with hexane solvent with stirring. The chromium loading (by mass of Cr) was 1.71%. And finally, drying the finished chromium-vanadium double-center composite catalyst for 5 hours at 80 ℃ in a nitrogen atmosphere to remove the solvent, and then storing the catalyst under the protection of nitrogen for later use.
Example 16:
10g of silica gel (pore volume of 1.5-1.7 cm)3A surface area of 250 to 300 m/g2Per g) was impregnated at 40 ℃ in an aqueous ammonium hexafluorovanadate solution with a vanadium loading (by mass of V) of 1.68%. After continuously stirring for 5 hours, heating to 120 ℃, drying in the air for 12 hours, then roasting the silica gel carrier impregnated with ammonium hexafluorovanadate at high temperature in a fluidized bed, and finally naturally cooling the sample under the protection of nitrogen. The temperature control process of the high-temperature roasting and then cooling is shown in figure 1. Then, toluene after dehydration, deoxidation and purification is used as a solvent, toluene isocyanate is used as an organizing agent to organize a vanadium source, the toluene isocyanate is refluxed and continuously stirred for 20 hours in a nitrogen atmosphere at 120 ℃ in a configuration bottle until the reaction is completed, and the organizing agent and the vanadium are mixedIs 1: 1. Next, the mixture was dried at 120 ℃ for 4 hours under vacuum to remove the solvent and stored under nitrogen. Finally, the organic chromium source bis (indenyl) chromium (II) was supported on the catalyst precursor obtained by the above method using dehydrated deoxygenated purified hexane as a solvent, and the reaction was continuously stirred in a flask at 45 ℃ under a nitrogen atmosphere for 6 hours until completion of the reaction. And then washed several times with hexane solvent with stirring. The chromium loading (by mass of Cr) was 1.71%. And finally, drying the finished chromium-vanadium double-center composite catalyst for 5 hours at 80 ℃ in a nitrogen atmosphere to remove the solvent, and then storing the catalyst under the protection of nitrogen for later use.
Example 17:
10g of silica gel (pore volume of 1.5-1.7 cm)3A surface area of 250 to 300 m/g2And/g) the catalyst was impregnated with an aqueous ammonium metavanadate solution having a concentration at 40 ℃ and a vanadium loading (in terms of the mass of V) of 1.68%. Continuously stirring for 5 hours, heating to 120 ℃, drying in air for 12 hours, then roasting the silica gel carrier impregnated with ammonium metavanadate at high temperature in a fluidized bed, and finally naturally cooling the sample under the protection of nitrogen. The temperature control process of the high-temperature roasting and then cooling is shown in figure 1. Then, the vanadium source was organized with toluene isocyanate using octane as a solvent after dehydration, deoxidation and purification, and the reaction was completed by refluxing and continuous stirring in a flask equipped with a nitrogen atmosphere at 120 ℃ for 20 hours until the reaction was completed, with the molar ratio of the organizing agent to vanadium being 1: 1. Next, the mixture was dried at 120 ℃ for 4 hours under vacuum to remove the solvent and stored under nitrogen. Finally, the organic chromium source bis (indenyl) chromium (II) was supported on the catalyst precursor obtained by the above method using dehydrated deoxygenated purified hexane as a solvent, and the reaction was continuously stirred in a flask at 45 ℃ under a nitrogen atmosphere for 6 hours until completion of the reaction. And then washed several times with hexane solvent with stirring. The chromium loading (by mass of Cr) was 1.71%. And finally, drying the finished chromium-vanadium double-center composite catalyst for 5 hours at 80 ℃ in a nitrogen atmosphere to remove the solvent, and then storing the catalyst under the protection of nitrogen for later use.
Example 18:
10g of silica gel (pore volume 1.5-1.7 c)m3A surface area of 250 to 300 m/g2Per g) was impregnated at 40 ℃ in an aqueous ammonium metavanadate solution with a vanadium loading (in terms of the mass of V) of 1.68%. Continuously stirring for 5 hours, heating to 120 ℃, drying in air for 12 hours, then roasting the silica gel carrier impregnated with ammonium metavanadate at high temperature in a fluidized bed, and finally naturally cooling the sample under the protection of nitrogen. The temperature control process of the high-temperature roasting and then cooling is shown in figure 1. Then, toluene after dehydration, deoxidation and purification was used as a solvent to organize the vanadium source by an organizing agent to tolyl isocyanate, and the mixture was refluxed and continuously stirred in a configuration bottle at 120 ℃ for 20 hours under a nitrogen atmosphere until the reaction was completed, and the molar ratio of the organizing agent to vanadium was 2: 1. Next, the mixture was dried at 120 ℃ for 4 hours under vacuum to remove the solvent and stored under nitrogen. Finally, the organic chromium source bis (indenyl) chromium (II) was supported on the catalyst precursor obtained by the above method using dehydrated deoxygenated purified hexane as a solvent, and the reaction was continuously stirred in a flask at 45 ℃ under a nitrogen atmosphere for 6 hours until completion of the reaction. And then washed several times with hexane solvent with stirring. The chromium loading (by mass of Cr) was 1.71%. And finally, drying the finished chromium-vanadium double-center composite catalyst for 5 hours at 80 ℃ in a nitrogen atmosphere to remove the solvent, and then storing the catalyst under the protection of nitrogen for later use.
Example 19:
10g of silica gel (pore volume of 1.5-1.7 cm)3A surface area of 250 to 300 m/g2Per g) was impregnated at 40 ℃ in an aqueous ammonium metavanadate solution with a vanadium loading (in terms of the mass of V) of 1.68%. Continuously stirring for 5 hours, heating to 120 ℃, drying in air for 12 hours, then roasting the silica gel carrier impregnated with ammonium metavanadate at high temperature in a fluidized bed, and finally naturally cooling the sample under the protection of nitrogen. The temperature control process of the high-temperature roasting and then cooling is shown in figure 1. Then, toluene after dehydration, deoxidation and purification was used as a solvent to organize the vanadium source by an organizing agent to tolyl isocyanate, and the mixture was refluxed and continuously stirred in a configuration bottle at 120 ℃ for 20 hours under a nitrogen atmosphere until the reaction was completed, and the molar ratio of the organizing agent to vanadium was 1: 1. Next, under vacuum conditions 1Dried at 20 ℃ for 4 hours to remove the solvent and stored under nitrogen. Finally, the organic chromium source bis (indenyl) chromium (II) was supported on the catalyst precursor obtained by the above method using dehydrated deoxygenated purified hexane as a solvent, and the reaction was continuously stirred in a flask at 45 ℃ under a nitrogen atmosphere for 6 hours until completion of the reaction. And then washed several times with hexane solvent with stirring. The chromium loading (by mass of Cr) was 1.71%. The resulting chromium-vanadium dual-site composite catalyst was dried at 80 ℃ for 5 hours under a nitrogen atmosphere to remove the solvent, and then pre-reduction-activated with the addition of an organometallic co-catalyst Triisobutylaluminum (TIBA) (example 19-1), Triethylaluminum (TEA) (example 19-2), Methylaluminoxane (MAO) (example 19-3), Diethylaluminum ethoxide (Diethylaluminum ethoxide) (example 19-4) and Diethylaluminum monochloride (DEAC) (example 19-5), respectively, wherein the concentration of the organometallic co-catalyst was 1.0mmol/mL and the amount was 1.98mL, i.e., Al/Cr (molar ratio) ═ 30. Drying at 80 deg.C under nitrogen atmosphere for 3 hr to remove solvent, and storing under nitrogen protection.
Example 20:
dissolving tetrabutyl titanate serving as a precursor in absolute ethyl alcohol according to a molar ratio of 1:1 to prepare a solution A, preparing distilled water and absolute ethyl alcohol according to a molar ratio of 1:10 to prepare a solution B, adding concentrated nitric acid to enable the pH value of the solution B to be 2-3, and mixing the solution A and the solution B to prepare TiO2Sol, wherein the concentration is such that the titanium loading (by mass of Ti) is 5%. Then, about 10g of silica gel (the pore volume is 1.5-1.7 cm)3A surface area of 250 to 300 m/g2/g) was added to the above sol and stirred well for 3 hours. Drying for 3-6 hours at 100 ℃ to remove the solvent, and then roasting at 400 ℃ for 4 hours in a drying air fluidized bed to obtain the titanium modified silica gel carrier prepared by a sol-gel method. And then, the titanium modified silica gel carrier is impregnated in an ammonium metavanadate aqueous solution with a certain concentration at 40 ℃, wherein the concentration enables the vanadium loading (based on the mass of V) to be 0.84%. Continuously stirring for 5 hours, heating to 120 ℃, drying in air for 12 hours, then roasting the titanium modified silica gel carrier impregnated with ammonium metavanadate at high temperature in a fluidized bed, and finally naturally cooling the sample under the protection of nitrogen. Wherein the above-mentioned high-temperature is calcinedThe temperature control process of the post-cooling is shown in FIG. 1. Then, toluene after dehydration, deoxidation and purification was used as a solvent to organize the vanadium source by an organizing agent to tolyl isocyanate, and the mixture was refluxed and continuously stirred in a configuration bottle at 120 ℃ for 20 hours under a nitrogen atmosphere until the reaction was completed, and the molar ratio of the organizing agent to vanadium was 1: 1. Next, the fully organized vanadium source-loaded support was dried under vacuum at 120 ℃ for 4 hours to remove the solvent and stored under nitrogen. Finally, the bis (indenyl) chromium (II) as an organochromium source was supported on the silica gel carrying vanadium prepared by the above method using dehydrated deoxygenated purified hexane as a solvent, and the reaction was continuously stirred in a flask at 45 ℃ under a nitrogen atmosphere for 6 hours until completion of the reaction. And then washed several times with hexane solvent with stirring. The chromium loading (by mass of Cr) was 1.71%. And finally, drying the finished titanium modified chromium-vanadium double-center composite catalyst for 5 hours at 80 ℃ in a nitrogen atmosphere to remove the solvent, and then storing the catalyst under the protection of nitrogen for later use.
Example 21:
taking tetrabutyl titanate as a precursor, weighing a certain amount of tetrabutyl titanate, and dissolving the tetrabutyl titanate in a hexane solvent refined by dehydration and deoxidation to prepare a tetrabutyl titanate solution, wherein the concentration enables the titanium loading (based on the mass of Ti) to be 5%. Then, about 10g of silica gel (the pore volume is 1.5-1.7 cm)3A surface area of 250 to 300 m/g2/g) was added to the above solution and stirred well for 4 h. Drying for 3-6 hours at 100 ℃ to remove the solvent, and then roasting at 400 ℃ for 4 hours in a drying air fluidized bed, namely preparing the titanium modified silica gel carrier by an impregnation method. And then, the titanium modified silica gel carrier is impregnated in an ammonium metavanadate aqueous solution with a certain concentration at 40 ℃, wherein the concentration enables the vanadium loading (based on the mass of V) to be 0.84%. Continuously stirring for 5 hours, heating to 120 ℃, drying in air for 12 hours, then roasting the titanium modified silica gel carrier impregnated with ammonium metavanadate at high temperature in a fluidized bed, and finally naturally cooling the sample under the protection of nitrogen. The temperature control process of the high-temperature roasting and then cooling is shown in figure 1. Then, toluene after dehydration, deoxidation and purification is used as a solvent, and a vanadium source is introduced into tolyl isocyanate by using an organizing agentAnd (3) performing organic reaction, refluxing the mixture in a nitrogen atmosphere at 120 ℃ in a configuration bottle and continuously stirring the mixture for 20 hours until the reaction is completed, wherein the molar ratio of the organic agent to the vanadium is 1: 1. Next, the fully organized supported vanadium source carrier was dried under vacuum at 120 ℃ for 4 hours to remove the solvent and stored under nitrogen protection. Finally, the organic chromium source bis (indenyl) chromium (II) was supported on the catalyst precursor obtained by the above method using dehydrated deoxygenated purified hexane as a solvent, and the reaction was continuously stirred in a flask at 45 ℃ under a nitrogen atmosphere for 6 hours until completion of the reaction. And then washed several times with hexane solvent with stirring. The chromium loading (by mass of Cr) was 1.71%. And finally, drying the finished titanium modified chromium-vanadium double-center composite catalyst for 5 hours at 80 ℃ in a nitrogen atmosphere to remove the solvent, and then storing the catalyst under the protection of nitrogen for later use.
Example 22:
10g of silica gel (pore volume of 1.5-1.7 cm)3A surface area of 250 to 300 m/g2Per g) at room temperature in an aqueous aluminum nitrate solution at a concentration such that the aluminum loading (by mass of Al) is 2%. Continuously stirring for 4-6 hours, heating to 120 ℃, drying in air for 8 hours, then roasting the carrier impregnated with the aluminum nitrate in a drying air fluidized bed at the high temperature of 600 ℃ for 4 hours, and finally naturally cooling the sample under the protection of nitrogen. And (3) obtaining an aluminum modified silica gel carrier, and then soaking the aluminum modified silica gel carrier in an ammonium metavanadate aqueous solution with a certain concentration at 40 ℃, wherein the concentration enables the vanadium loading (based on the mass of V) to be 1.68%. Continuously stirring for 5 hours, heating to 120 ℃, drying in air for 12 hours, then roasting the aluminum modified silica gel carrier impregnated with ammonium metavanadate at high temperature in a fluidized bed, and finally naturally cooling the sample under the protection of nitrogen. The temperature control process of the high-temperature roasting and then cooling is shown in figure 1. Then, toluene after dehydration, deoxidation and purification was used as a solvent to organize the vanadium source by an organizing agent to tolyl isocyanate, and the mixture was refluxed and continuously stirred in a configuration bottle at 120 ℃ for 20 hours under a nitrogen atmosphere until the reaction was completed, and the molar ratio of the organizing agent to vanadium was 1: 1. Then, the completely organized carrier loaded with the vanadium source is put into the vacuum chamberDried at 120 ℃ for 4 hours under empty conditions to remove the solvent and stored under nitrogen. Finally, the bis (indenyl) chromium (II) as an organochromium source was supported on the silica gel carrying vanadium prepared by the above method using dehydrated deoxygenated purified hexane as a solvent, and the reaction was continuously stirred in a flask at 45 ℃ under a nitrogen atmosphere for 6 hours until completion of the reaction. And then washed several times with hexane solvent with stirring. The chromium loading (by mass of Cr) was 1.71%. And finally, drying the finished aluminum modified chromium-vanadium double-center composite catalyst for 5 hours at 80 ℃ in a nitrogen atmosphere to remove the solvent, and then storing the catalyst under the protection of nitrogen for later use.
Example 23:
about 10g of silica gel (pore volume of 1.5-1.7 cm)3A surface area of 250 to 300 m/g2Per g) at room temperature in an aqueous ammonium hexafluorosilicate solution at a concentration such that the fluorine loading (by mass of F) is 1.5%. Continuously stirring for 4-6 hours, heating to 120 ℃, drying in air for 8 hours, then roasting the carrier impregnated with ammonium hexafluorosilicate in a nitrogen fluidized bed at high temperature of 500 ℃ for 4 hours, and finally naturally cooling the sample under the protection of nitrogen. Obtaining a fluorine-modified silica gel carrier, and then soaking the fluorine-modified silica gel carrier in an ammonium metavanadate aqueous solution with a certain concentration at 40 ℃, wherein the concentration enables the vanadium loading (based on the mass of V) to be 1.68%. Continuously stirring for 5 hours, heating to 120 ℃, drying in air for 12 hours, then roasting the fluorine modified silica gel carrier impregnated with ammonium metavanadate at high temperature in a fluidized bed, and finally naturally cooling the sample under the protection of nitrogen. The temperature control process of the high-temperature roasting and then cooling is shown in figure 1. Then, toluene after dehydration, deoxidation and purification was used as a solvent to organize the vanadium source by an organizing agent to tolyl isocyanate, and the mixture was refluxed and continuously stirred in a configuration bottle at 120 ℃ for 20 hours under a nitrogen atmosphere until the reaction was completed, and the molar ratio of the organizing agent to vanadium was 1: 1. Next, the fully organized vanadium source-loaded support was dried under vacuum at 120 ℃ for 4 hours to remove the solvent and stored under nitrogen. Finally, the organic chromium source bis (indenyl) chromium (II) is supported by using dehydrated, deoxidized and purified hexane as a solventThe vanadium-loaded silica gel obtained by the method is continuously stirred for 6 hours in a nitrogen atmosphere at 45 ℃ in a preparation bottle until the reaction is completed. And then washed several times with hexane solvent with stirring. The chromium loading (by mass of Cr) was 1.71%. And finally, drying the finished fluorine modified chromium-vanadium double-center composite catalyst for 5 hours at 80 ℃ in a nitrogen atmosphere to remove the solvent, and then storing the catalyst under the protection of nitrogen for later use.
Example 24:
200mg of each catalyst in examples 1 to 18 and 20 to 23 was weighed out for polymerization experiments. The polymerization reaction kettle is heated in vacuum (100 ℃) in advance, then high-purity nitrogen is replaced, the operation is repeated for three times, a small amount of monomer ethylene is used for replacing once, and finally the reaction kettle is filled with ethylene to the micro positive pressure (0.12 MPa). The polymerization temperature was controlled at 90 ℃. About 200mL of dehydrated and deoxidized purified heptane as a solvent, Triisobutylaluminum (TIBA) as a co-catalyst, 1.0mmol/mL of the co-catalyst (n-heptane solution) and 1.98mL of the co-catalyst, i.e., Al/Cr (molar ratio) of 30 were sequentially added to a reaction vessel, and finally the ethylene pressure in the reaction vessel was increased to 1MPa and the catalyst was added to start the polymerization reaction. The instantaneous consumption of monomer ethylene (via a high precision ethylene mass flow meter connected to a computer) was collected on-line during the reaction and recorded by the computer. The reaction was terminated after 1 hour at 90 ℃ and the polymer was dried under vacuum and weighed and analyzed.
Example 25:
polymerization experiments were carried out weighing 200mg of the catalyst from example 18. The polymerization reaction kettle is heated in vacuum (100 ℃) in advance, then high-purity nitrogen is replaced, the operation is repeated for three times, a small amount of monomer ethylene is used for replacing once, and finally the reaction kettle is filled with ethylene to the micro positive pressure (0.12 MPa). The polymerization temperature was controlled at 90 ℃. Adding about 200mL of refined heptane subjected to dehydration and deoxidation treatment into a reaction kettle in sequence as a solvent, finally adjusting the pressure of ethylene in the reaction kettle to 1MPa, and adding a catalyst to start a polymerization reaction. The instantaneous consumption of monomer ethylene (via a high precision ethylene mass flow meter connected to a computer) was collected on-line during the reaction and recorded by the computer. The reaction was terminated after 1 hour at 90 ℃ and the polymer was dried under vacuum and weighed and analyzed.
Example 26:
polymerization experiments were carried out by weighing 200mg of the catalyst of example 2. The polymerization reaction kettle is heated in vacuum (100 ℃) in advance, then high-purity nitrogen is replaced, the operation is repeated for three times, a small amount of monomer ethylene is used for replacing once, and finally the reaction kettle is filled with ethylene to the micro positive pressure (0.12 MPa). The polymerization temperature was controlled at 90 ℃. About 200mL of purified heptane after dehydration-deoxidation treatment was sequentially added to the reaction vessel as a solvent, and Triethylaluminum (TIBA) (example 26-1), Triethylaluminum (TEA) (example 26-2), Methylaluminoxane (MAO) (example 26-3), Diethylaluminum ethoxide (example 26-4) and Diethylaluminum monochloride (DEAC) (example 26-5) were used as co-catalysts, the concentration of the co-catalyst was 1.0mmol/mL (n-heptane solution), the amount of the co-catalyst was 1.98mL, i.e., Al/Cr (molar ratio) was 30, and finally, the ethylene pressure in the reaction vessel was increased to 1MPa and the catalyst was added to start the polymerization reaction. The instantaneous consumption of monomer ethylene (via a high precision ethylene mass flow meter connected to a computer) was collected on-line during the reaction and recorded by the computer. The reaction was terminated after 1 hour at 90 ℃ and the polymer was dried under vacuum and weighed and analyzed.
Example 27:
polymerization experiments were carried out by weighing 200mg of the catalyst of example 2. The polymerization reaction kettle is heated in vacuum (100 ℃) in advance, then high-purity nitrogen is replaced, the operation is repeated for three times, a small amount of monomer ethylene is used for replacing once, and finally the reaction kettle is filled with ethylene to the micro positive pressure (0.12 MPa). The polymerization temperature was controlled at 90 ℃. About 200mL of dehydrated and deoxygenated purified heptane as a solvent and Triisobutylaluminum (TIBA) as a co-catalyst in the form of a 1.0mmol/mL (n-heptane solution) concentration were sequentially added to a reaction vessel in the form of 0.66mL, 1.32mL, 1.98mL, 2.63mL, and 3.29mL, respectively, i.e., Al/Cr (molar ratio) of 10 (example 27-1), 20 (example 27-2), 30 (example 27-3), 40 (example 27-4), and 50 (example 27-5), and finally the ethylene pressure in the reaction vessel was increased to 1MPa and the catalyst was added to start the polymerization reaction. The instantaneous consumption of monomer ethylene (via a high precision ethylene mass flow meter connected to a computer) was collected on-line during the reaction and recorded by the computer. The reaction was terminated after 1 hour at 90 ℃ and the polymer was dried under vacuum and weighed and analyzed.
Example 28:
polymerization experiments were carried out by weighing 200mg of the catalyst of example 2. The polymerization reaction kettle is heated in vacuum (100 ℃) in advance, then high-purity nitrogen is replaced, the operation is repeated for three times, a small amount of monomer ethylene is used for replacing once, and finally the reaction kettle is filled with ethylene to the micro positive pressure (0.12 MPa). The polymerization temperature was controlled at 90 ℃. About 200mL of dehydrated and deoxygenated purified heptane as a solvent and Triisobutylaluminum (TIBA) as a co-catalyst in a concentration of 1.0mmol/mL (n-heptane solution) in an amount of 1.98mL, i.e., Al/Cr (molar ratio) of 30 were sequentially added to a reaction vessel, and finally the ethylene pressure in the reaction vessel was increased to 0.4MPa (example 28-1), 0.6MPa (example 28-2), 0.8MPa (example 28-3) and 1MPa (example 28-4), respectively, and a catalyst was added to start a polymerization reaction. The instantaneous consumption of monomer ethylene (via a high precision ethylene mass flow meter connected to a computer) was collected on-line during the reaction and recorded by the computer. The reaction was terminated after 1 hour at 90 ℃ and the polymer was dried under vacuum and weighed and analyzed.
Example 29:
polymerization experiments were carried out by weighing 200mg of the catalyst of example 2. The polymerization reaction kettle is heated in vacuum (100 ℃) in advance, then high-purity nitrogen is replaced, the operation is repeated for three times, a small amount of monomer ethylene is used for replacing once, and finally the reaction kettle is filled with ethylene to the micro positive pressure (0.12 MPa). The polymerization temperature was controlled at 90 ℃. About 200mL of purified heptane subjected to dehydration-deoxidation treatment was sequentially charged into the reaction vessel as a solvent, purified 1-hexene subjected to dehydration-deoxidation treatment was used as a comonomer, and Triisobutylaluminum (TIBA) was used as a co-catalyst, wherein the 1-hexene was used in an amount of 2mL, 6mL, 10mL, and 14mL, respectively, that is, the volume ratios of 1-hexene to the solvent used for polymerization were 1 vol% (example 29-1), 3 vol% (example 29-2), 5 vol% (example 29-3), and 7 vol% (example 29-4). The concentration of the cocatalyst was 1.0mmol/mL (n-heptane solution), the amount was 1.98mL, i.e., Al/Cr (molar ratio) was 30, and finally the ethylene pressure in the reactor was increased to 1MPa and the catalyst was added to start the polymerization. The instantaneous consumption of monomer ethylene (via a high precision ethylene mass flow meter connected to a computer) was collected on-line during the reaction and recorded by the computer. The reaction was terminated after 1 hour at 90 ℃ and the polymer was dried under vacuum and weighed and analyzed.
Example 30:
polymerization experiments were carried out by weighing 200mg of the catalyst of example 2. The polymerization reaction kettle is heated in vacuum (100 ℃) in advance, then high-purity nitrogen is replaced, the operation is repeated for three times, a small amount of monomer ethylene is used for replacing once, and finally the reaction kettle is filled with ethylene to the micro positive pressure (0.12 MPa). The polymerization temperature was controlled at 90 ℃. About 200mL of refined heptane subjected to dehydration and deoxidation treatment is taken as a solvent, refined 1-hexene subjected to dehydration and deoxidation treatment is taken as a comonomer, and Triisobutylaluminum (TIBA) is taken as a cocatalyst, wherein the dosage of the 1-hexene is 6mL, namely the volume ratio of the 1-hexene to the solvent used for polymerization is 3 vol%. The cocatalyst concentration was 1.0mmol/mL (n-heptane solution) in an amount of 0.66mL, 1.32mL, 1.98mL, 2.63mL, and 3.29mL, respectively, i.e., Al/Cr (molar ratio) was 10 (example 30-1), 20 (example 30-2), 30 (example 30-3), 40 (example 30-4), and 50 (example 30-5), and finally the ethylene pressure in the reactor was increased to 1MPa and the catalyst was added to start the polymerization reaction. The instantaneous consumption of monomer ethylene (via a high precision ethylene mass flow meter connected to a computer) was collected on-line during the reaction and recorded by the computer. The reaction was terminated after 1 hour at 90 ℃ and the polymer was dried under vacuum and weighed and analyzed.
Example 31:
polymerization experiments were carried out by weighing 200mg of the catalyst of example 2. The polymerization reaction kettle is heated in vacuum (100 ℃) in advance, then high-purity nitrogen is replaced, the operation is repeated for three times, a small amount of monomer ethylene is used for replacing once, and finally the reaction kettle is filled with ethylene to the micro positive pressure (0.12 MPa). The polymerization temperature was controlled at 90 ℃. About 200mL of dehydrated and deoxygenated purified heptane as a solvent and Triisobutylaluminum (TIBA) as a co-catalyst were sequentially added to a reaction vessel, wherein the co-catalyst concentration was 1.0mmol/mL (n-heptane solution) and the amount was 1.98mL, i.e., Al/Cr (molar ratio) was 30, and hydrogen volumes were 1 vol% (example 31-1), 3 vol% (example 31-2), 5 vol% (example 31-3), and 7 vol% (example 31-4) of the vessel volume, respectively. Finally, the ethylene pressure in the reaction kettle is increased to 1MPa, and a catalyst is added to start a polymerization reaction. The instantaneous consumption of monomer ethylene (via a high precision ethylene mass flow meter connected to a computer) was collected on-line during the reaction and recorded by the computer. The reaction was terminated after 1 hour at 90 ℃ and the polymer was dried under vacuum and weighed and analyzed.
Example 32:
polymerization experiments were carried out by weighing 200mg of the catalyst of example 2. The polymerization reaction kettle is heated in vacuum (100 ℃) in advance, then high-purity nitrogen is replaced, the operation is repeated for three times, a small amount of monomer ethylene is used for replacing once, and finally the reaction kettle is filled with ethylene to the micro positive pressure (0.12 MPa). The polymerization temperature was controlled at 90 ℃. About 200mL of refined heptane subjected to dehydration and deoxidation treatment is taken as a solvent, refined 1-hexene subjected to dehydration and deoxidation treatment is taken as a comonomer, and Triisobutylaluminum (TIBA) is taken as a cocatalyst, wherein the dosage of the 1-hexene is 6mL, namely the volume ratio of the 1-hexene to the solvent used for polymerization is 3 vol%. The cocatalyst concentration was 1.0mmol/mL (n-heptane solution) and the amount used was 1.98mL, i.e., Al/Cr (molar ratio) was 30, and 1 vol% (example 32-1), 3 vol% (example 32-2), 5 vol% (example 32-3) and 7 vol% (example 32-4) of hydrogen volume based on the pot volume were added, respectively. Finally, the ethylene pressure in the reaction kettle is increased to 1MPa, and a catalyst is added to start a polymerization reaction. The instantaneous consumption of monomer ethylene (via a high precision ethylene mass flow meter connected to a computer) was collected on-line during the reaction and recorded by the computer. The reaction was terminated after 1 hour at 90 ℃ and the polymer was dried under vacuum and weighed and analyzed.
Comparative example 1:
about 10g of silica gel (pore volume of 1.5-1.7 cm)3A surface area of 250-300m2/g) was treated at 600 ℃ with purified hexane after dehydration-deoxidation treatment as a solvent, bis (indenyl) chromium (II) was supported on the 600 ℃ treated silica gel support and stirred continuously at 45 ℃ under nitrogen atmosphere in a configuration bottle for 6 hours until the reaction was complete. Reuse ofThe hexane solvent was washed several times with stirring. The amount of supported chromium (in terms of the mass of Cr) was 1.71%, and an S-9 catalyst was obtained. 200mg of the prepared S-9 catalyst was weighed out for a polymerization experiment. The polymerization reaction kettle is heated in vacuum (100 ℃) in advance, then high-purity nitrogen is replaced, the operation is repeated for three times, a small amount of monomer ethylene is used for replacing once, and finally the reaction kettle is filled with ethylene to the micro positive pressure (0.12 MPa). The polymerization temperature was controlled at 90 ℃. About 200mL of dehydrated and deoxidized purified heptane as a solvent, Triisobutylaluminum (TIBA) as a co-catalyst, 1.0mmol/mL of the co-catalyst (n-heptane solution) and 1.98mL of the co-catalyst, i.e., Al/Cr (molar ratio) of 30 were sequentially added to a reaction vessel, and finally the ethylene pressure in the reaction vessel was increased to 1MPa and the catalyst was added to start the polymerization reaction. The instantaneous consumption of monomer ethylene (via a high precision ethylene mass flow meter connected to a computer) was collected on-line during the reaction and recorded by the computer. The reaction was terminated after 1 hour at 90 ℃ and the polymer was dried under vacuum and weighed and analyzed.
Comparative example 2:
about 10g of silica gel (pore volume of 1.5-1.7 cm)3A surface area of 250-300m2Per g) in an aqueous ammonium metavanadate solution at 40 ℃ at a concentration such that the vanadium loading (in terms of the mass of V) is 1.68%. Continuously stirring for 5 hours, heating to 120 ℃, drying in air for 12 hours, then roasting the silica gel carrier loaded with ammonium metavanadate at high temperature in a fluidized bed, and finally naturally cooling the sample under the protection of nitrogen. The temperature control process of the high-temperature roasting and then cooling is shown in figure 1. Then, toluene after dehydration, deoxidation and purification was used as a solvent to organize the vanadium source by an organizing agent to tolyl isocyanate, and the mixture was refluxed and continuously stirred in a configuration bottle at 120 ℃ for 20 hours under a nitrogen atmosphere until the reaction was completed, and the molar ratio of the organizing agent to vanadium was 1: 1. Next, the fully organized vanadium source-loaded support was dried under vacuum at 120 ℃ for 4 hours to remove the solvent and stored under nitrogen. To prepare the silica gel loaded organic vanadium catalyst. 200mg of the prepared organic vanadium catalyst is weighed for a polymerization experiment. The polymerization reactor was previously subjected to vacuum heating (100)Then replacing with high-purity nitrogen, repeatedly operating for three times, replacing with a small amount of monomer ethylene once, and finally filling ethylene into the reaction kettle to a micro positive pressure (0.12 MPa). The polymerization temperature was controlled at 90 ℃. About 200mL of dehydrated and deoxidized purified heptane as a solvent, Triisobutylaluminum (TIBA) as a co-catalyst, 1.0mmol/mL of the co-catalyst (n-heptane solution) and 1.98mL of the co-catalyst, i.e., Al/Cr (molar ratio) of 30 were sequentially added to a reaction vessel, and finally the ethylene pressure in the reaction vessel was increased to 1MPa and the catalyst was added to start the polymerization reaction. The instantaneous consumption of monomer ethylene (via a high precision ethylene mass flow meter connected to a computer) was collected on-line during the reaction and recorded by the computer. The reaction was terminated after 1 hour at 90 ℃ and the polymer was dried under vacuum and weighed and analyzed.
Comparative example 3:
s-9 prepared in comparative examples 1 and 2 and the organic vanadium catalyst were mechanically mixed (1 to 1 by weight of the catalyst). 200mg of the mechanically mixed catalyst was weighed out for a polymerization experiment. The polymerization reaction kettle is heated in vacuum (100 ℃) in advance, then high-purity nitrogen is replaced, the operation is repeated for three times, a small amount of monomer ethylene is used for replacing once, and finally the reaction kettle is filled with ethylene to the micro positive pressure (0.12 MPa). The polymerization temperature was controlled at 90 ℃. About 200mL of dehydrated and deoxidized purified heptane as a solvent, Triisobutylaluminum (TIBA) as a co-catalyst, 1.0mmol/mL of the co-catalyst (n-heptane solution) and 1.98mL of the co-catalyst, i.e., Al/Cr (molar ratio) of 30 were sequentially added to a reaction vessel, and finally the ethylene pressure in the reaction vessel was increased to 1MPa and the catalyst was added to start the polymerization reaction. The instantaneous consumption of monomer ethylene (via a high precision ethylene mass flow meter connected to a computer) was collected on-line during the reaction and recorded by the computer. The reaction was terminated after 1 hour at 90 ℃ and the polymer was dried under vacuum and weighed and analyzed.
(1) Effect of different catalyst preparation methods on ethylene polymerization:
TABLE 1 influence of different catalyst preparation methods on ethylene homopolymerization
Figure BDA0002214368510000351
Polymerization conditions: ethylene pressure 1.0 MPa; the polymerization time is 1 hr; the polymerization temperature is 90 ℃; 200mL of n-heptane; the dosage of the catalyst is 200 mg; cocatalyst TIBA, Al/Cr 30; the total chromium loading was 1.71 wt%.
The results of ethylene polymerization for different catalyst preparation methods are given in table 1. Through the change of polymerization activity, the chromium-vanadium double-center composite catalyst is found to be obviously superior to a pure S-9 catalyst, an organic vanadium catalyst and a catalyst mechanically mixed with the pure S-9 catalyst and the organic vanadium catalyst, and the chromium-vanadium double-center composite catalyst has great advantages in polymerization.
(2) Influence of different organic vanadium ratios on ethylene polymerization:
TABLE 2 influence of organic vanadium ratio on ethylene homopolymerization
Figure BDA0002214368510000352
Polymerization conditions: ethylene pressure 1.0 MPa; the polymerization time is 1 hr; the polymerization temperature is 90 ℃; 200mL of n-heptane; the dosage of the catalyst is 200 mg; cocatalyst TIBA, Al/Cr 30; the total chromium loading was 1.71 wt%. Wherein examples 1-24 refer to the catalyst prepared in example 1, olefin polymerization was carried out according to the method of example 24. Other embodiments are numbered the same way.
The results of ethylene polymerization at different organic vanadium ratios are given in table 2. With the increase of the addition of the organic vanadium component, the ethylene homopolymerization activity of the catalyst is continuously improved. Analysis on the product polyethylene shows that with the increase of the addition amount of the organic vanadium component, the high molecular weight part of the product polyethylene is increased obviously, the molecular weight distribution is narrowed, and the melting points of the product are relatively close.
(3) Effect of different inorganic supports on ethylene polymerization:
TABLE 3 Effect of different inorganic Carriers on ethylene homopolymerization
Figure BDA0002214368510000361
Polymerization conditions: ethylene pressure 1.0 MPa; the polymerization time is 1 hr; the polymerization temperature is 90 ℃; 200mL of n-heptane; the dosage of the catalyst is 200 mg; cocatalyst TIBA, Al/Cr 30; the total chromium loading was 1.71 wt%.
Table 3 shows the results of ethylene polymerization in the preparation of chromium vanadium dual-site composite catalysts on different inorganic supports. Through the change of polymerization activity, the chromium-vanadium double-center composite catalyst prepared by using silica gel as a carrier is better than the chromium-vanadium double-center composite catalyst prepared by using other two inorganic carriers.
(4) Effect of different chromium sources on ethylene polymerization:
TABLE 4 influence of different chromium sources on ethylene homopolymerization
Figure BDA0002214368510000362
Polymerization conditions: ethylene pressure 1.0 MPa; the polymerization time is 1 hr; the polymerization temperature is 90 ℃; 200mL of n-heptane; the dosage of the catalyst is 200 mg; cocatalyst TIBA, Al/Cr 30; the total chromium loading was 1.71 wt%.
Table 4 shows the results of the ethylene polymerization effect of preparing a chromium vanadium dual-site composite catalyst with different organic chromium sources. Through the change of polymerization activity, the chromium-vanadium double-center composite catalyst prepared by using bis (indenyl) chromium (II) as an organic chromium source is superior to the chromium-vanadium double-center composite catalyst prepared by other organic chromium sources.
(5) Effect of Co-catalyst on polymerization:
TABLE 5 Effect of different Co-catalysts on ethylene homopolymerization
Figure BDA0002214368510000371
Polymerization conditions: cr/v (mol) 1: 1; ethylene pressure 1.0 MPa; the polymerization time is 1 hr; the polymerization temperature is 90 ℃; 200mL of n-heptane; the dosage of the catalyst is 200 mg; Al/Cr ═ 30; the total chromium loading was 1.71 wt%.
From the results in Table 5, it can be seen that the selection of TIBA as the promoter is more reactive than the other promoters. In terms of molecular weight, the product obtained by taking TIBA as a cocatalyst has higher molecular weight.
TABLE 6 Effect of Co-catalyst amounts on ethylene homopolymerization
Figure BDA0002214368510000372
Polymerization conditions: cr/v (mol) 1: 1; ethylene pressure 1.0 MPa; the polymerization time is 1 hr; the polymerization temperature is 90 ℃; 200mL of n-heptane; the dosage of the catalyst is 200 mg; cocatalyst ═ TIBA; the total chromium loading was 1.71 wt%.
The results of the ethylene polymerization with different amounts of cocatalyst are given in Table 6. From the results, it can be seen that in the case of using TIBA as a cocatalyst, the reactivity shows a process of increasing first and then decreasing with the increase of the amount of the cocatalyst, indicating that the amount of the cocatalyst has a suitable value or range for achieving high polymerization activity. Similar laws apply to cocatalysts other than TIBA. And the high molecular weight fraction of the product is increasing with increasing amounts of cocatalyst.
(6) Effect of ethylene pressure on polymerization reaction:
TABLE 7 influence of ethylene pressure on ethylene homopolymerization
Figure BDA0002214368510000381
Polymerization conditions: cr/v (mol) 1: 1; the polymerization time is 1 hr; the polymerization temperature is 90 ℃; 200mL of n-heptane; the dosage of the catalyst is 200 mg; cocatalyst TIBA, Al/Cr 30; the total chromium loading was 1.71 wt%.
The results of ethylene homopolymerization under different ethylene pressures are given in Table 7. It can be seen from the results that the polymerization activity was significantly improved with increasing ethylene pressure, and the molecular weight of the resulting polyethylene product was also increased with increasing pressure.
(7) Effect of different comonomer concentrations on the polymerization reaction:
TABLE 8 Effect of comonomer concentration on ethylene copolymerization
Figure BDA0002214368510000382
Polymerization conditions: cr/v (mol) 1: 1; ethylene pressure 1.0 MPa; the polymerization time is 1 hr; the polymerization temperature is 90 ℃; 200mL of n-heptane; the dosage of the catalyst is 200 mg; cocatalyst TIBA, Al/Cr 30; the total chromium loading was 1.71 wt%.
Table 8 shows the results of the ethylene/1-hexene copolymerization with the chromium vanadium dual-site composite catalyst. The reactivity showed a tendency to decrease with increasing 1-hexene addition, and the ethylene/1-hexene copolymerization activities were all lower than those of the previous ethylene homopolymerization. The addition of the comonomer can reduce the melting point of the product polyethylene compared with the homopolymerization product, and the melting point of the product polyethylene is obviously reduced along with the increase of the addition amount. The low molecular weight fraction of the product increases with increasing comonomer addition and the molecular weight distribution gradually broadens.
(8) Effect of different cocatalyst concentrations on the copolymerization reaction:
TABLE 9 Effect of cocatalyst concentration on ethylene copolymerization
Figure BDA0002214368510000391
Polymerization conditions: cr/v (mol) 1: 1; ethylene pressure 1.0 MPa; the polymerization time is 1 hr; the polymerization temperature is 90 ℃; 200mL of n-heptane; the dosage of the catalyst is 200 mg; cocatalyst ═ TIBA; the total chromium loading is 1.71 wt%; the 1-hexene concentration was 3 vol%.
As can be seen from the results in Table 9, under the condition of 3 vol% of 1-hexene added, the reactivity shows a process of increasing first and then decreasing with the increasing amount of the cocatalyst, and the high molecular weight fraction of the product increases with the increasing amount of the cocatalyst as in the case of ethylene homopolymerization.
The present invention is capable of other embodiments, and various changes and modifications may be made by one skilled in the art without departing from the spirit and scope of the invention as defined in the appended claims.

Claims (16)

1. A double-center supported catalyst is characterized by comprising a carrier and an active component, wherein the carrier is an inorganic carrier, the active component is a vanadium-containing organic compound and a chromium-containing organic compound, the vanadium-containing organic compound is chemically bonded with the carrier through oxygen in a connection mode, and the chromium-containing organic compound is chemically bonded with the carrier through oxygen in a connection mode;
the vanadium-containing organic compound comprises the following structure:
V＝N-R1
wherein R is1Is a substituted or unsubstituted hydrocarbyl group having 1 to 10 carbon atoms;
the chromium-containing organic compound comprises the following structure:
Cr-R2
wherein R is2Is a substituted or unsubstituted cyclopentadienyl, indenyl or fluorenyl;
the substituents of the cyclopentadienyl, indenyl and fluorenyl groups are hydrocarbon groups having 0 to 10 carbon atoms.
2. The dual site supported catalyst of claim 1 wherein the substituted cyclopentadienyl has the structure:
Figure FDA0002214368500000011
wherein, R is3、R4、R5、R6And R7Each independently is an aliphatic hydrocarbon group of 0 to 10 carbon atoms;
the substituted indenyl group has the following structure:
Figure FDA0002214368500000012
wherein, R is8、R9、R10、R11、R12、R13And R14Each independently is an aliphatic hydrocarbon group of 0 to 10 carbon atoms;
the substituted fluorenyl group has the following structure:
Figure FDA0002214368500000021
wherein, R is15、R16、R17、R18、R19、R20、R21、R22And R23Each independently an aliphatic hydrocarbon group of 0 to 10 carbon atoms.
3. The dual site supported catalyst of claim 2, wherein R is3、R4、R5、R6And R7Each independently is hydrogen, methyl, ethyl, propyl or butyl; the R is8、R9、R10、R11、R12、R13And R14Each independently is hydrogen, methyl, ethyl, propyl or butyl, R15、R16、R17、R18、R19、R20、R21、R22And R23Each independently hydrogen, methyl, ethyl, propyl or butyl.
4. The dual site supported catalyst of claim 1, wherein R is1Is substituted or unsubstituted aromatic hydrocarbon radical with 1-10 carbon atoms, and the substituted radical is halogen or nitreOne or more of alkyl and alkoxy.
5. The dual-site supported catalyst according to claim 1, wherein the inorganic carrier is one or more selected from the group consisting of silica, alumina, titania, zirconia, magnesia, calcia and inorganic clay.
6. The dual-site supported catalyst according to claim 5, wherein the inorganic support is silica, and the silica is unmodified amorphous silica or amorphous porous silica gel modified with Ti, Al or F; the pore volume of the inorganic carrier is 0.5-5.0 cm3The surface area of the inorganic carrier is 50-800 m2/g。
7. The double-center supported catalyst according to claim 1, wherein the loading amount of the chromium-containing organic compound is 0.01-20 wt% in terms of chromium based on the total weight of the catalyst; the loading amount of the chromium-containing organic compound is calculated by chromium, the loading amount of the vanadium-containing organic compound is calculated by vanadium, and the weight ratio of the loading amount of the vanadium-containing organic compound to the loading amount of the chromium-containing organic compound is 0.1-5: 1.
8. A preparation method of a double-center supported catalyst is characterized by comprising the following steps:
step 1, dipping a carrier into a solution containing a vanadium source, drying and roasting;
step 2, adding the product obtained in the step 1 into a solution of a vanadium organic reagent, and reacting to obtain the catalyst loaded with the vanadium organic compound, wherein the vanadium organic reagent has the following structure:
R1-N＝C＝O
wherein R is1Is a substituted or unsubstituted hydrocarbyl group having 1 to 10 carbon atoms; and
step 3, dipping the catalyst loaded with the vanadium-containing organic compound into the solution of the organic chromium source to obtain a double-center supported catalyst;
the organic chromium source comprises the following structure:
R2'-Cr-R2
wherein R is2And R2' are each independently substituted or unsubstituted cyclopentadienyl, indenyl, or fluorenyl; the substituents of the cyclopentadienyl, indenyl and fluorenyl groups are hydrocarbon groups having 0 to 10 carbon atoms.
9. The method of claim 8, further comprising a step of pre-reducing the dual-site supported catalyst obtained in step 3 with an organometallic co-catalyst.
10. The method for preparing a dual site supported catalyst according to claim 8, wherein the step 2 is performed in an inert atmosphere or under vacuum.
11. The method for preparing a double-center supported catalyst according to claim 8, wherein the vanadium source is a water-soluble vanadium-containing salt or a water-insoluble vanadium-containing salt; the water-soluble vanadium-containing salt is nitrate, phosphate, sulfate, acetate or metavanadate of vanadium, and the water-insoluble vanadium-containing salt is vanadium bisacetylacetonate oxide, vanadium triisopropoxide, vanadium tripropanolate oxide, vanadium acetylacetonate, vanadium triethoxide, vanadyl chloride or vanadium trisilicide.
12. The method of claim 11, wherein the water-soluble vanadium-containing salt is ammonium hexafluorovanadate, vanadium nitrate, vanadyl oxalate, ammonium metavanadate, vanadyl sulfate, vanadium (iv) oxide sulfate hydrate, vanadium (iii) sulfate, vanadium oxide trichloride, sodium orthovanadate, sodium metavanadate, or vanadium acetate present in an acid solution.
13. The method of claim 8, wherein R is selected from the group consisting of1Is substituted or unsubstituted aromatic hydrocarbon radical with 1-10 carbon atoms, and the substituted radical is one or more of halogen, nitro and alkoxy.
14. The method for preparing the dual-center supported catalyst according to claim 13, wherein the organic chromium source is one or more selected from the group consisting of bis (cyclopentadiene) chromium (II), bis (ethylcyclopentadiene) chromium (II), bis (pentamethylcyclopentadiene) chromium (II), bis (tetramethylcyclopentadiene) chromium (II), and bis (isopropylcyclopentadiene) chromium (II).
15. The preparation method of the double-center supported catalyst according to claim 8, wherein the addition amount of the organic chromium source is 0.01-20 wt% in terms of chromium based on the weight of the carrier, the addition amount of the vanadium source is in terms of vanadium, and the ratio of the addition amount of the vanadium source to the addition amount of the organic chromium source is 0.1-5: 1.
16. Use of a dual site supported catalyst according to any of claims 1 to 7 in ethylene polymerization reactions.
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