KR100427145B1 - Chelate catalyst for olefin polymerization and olefin polymerization method using the same - Google Patents

Abstract

The present invention relates to a chelating catalyst for olefin polymerization and an olefin polymerization method using the same, and more particularly, to prepare a liquid titanium compound chelate-bonded with an imidazole-based ligand, and polymerizing olefin using the catalyst as a main catalyst component. The present invention relates to a chelate catalyst for olefin polymerization and a method for olefin polymerization using the same.

Description

Chelate catalyst for olefin polymerization and olefin polymerization method using the same {Chelate catalyst for olefin polymerization and olefin polymerization method using the same}

The present invention relates to a chelate catalyst for olefin polymerization and an olefin polymerization method using the same, and more particularly, to an olefin polymerization chelate catalyst composed of a liquid titanium compound chelate-bonded with an imidazole-based ligand, and an olefin polymerization method using the same. It is about.

Efforts have been made to improve the properties of polymers produced by changing the reaction environment of transition metal compounds in olefin polymerization reactions in which the transition metal compounds react with olefins. In particular, efforts to control the reaction environment in which the transition metal compound reacts with the olefin using the metallocene compound obtained by converting the ligand of the transition metal compound into the cyclopentadiine ligand have made significant progress.

In the 80's, homogeneous catalysts using metallocene compounds began to attract the spotlight due to their excellent (co) polymerization properties with alpha olefins, such as impact strength and transparency. In particular, by synthesizing a metallocene compound having a special substituent such as an indenyl group, a cycloheptadiene group, a fluorenyl group, which controls an electronic or steric spatial environment in a cyclopentadienyl group Metallocene catalysts that can control stereoregularity and molecular weight of polymers have been developed and are expanding their applications.

In recent years, the development of a catalyst capable of controlling the particle properties of a polymer while producing an excellent copolymer by preparing a metallocene compound on an inorganic carrier to produce a non-uniform catalyst has been actively developed. For example, U. S. Patent No. 5,439, 995 and U. S. Patent No. 5, 455, 316, etc., disclose the preparation of a non-uniform catalyst having excellent particle properties and excellent copolymerization properties by supporting zirconocene and titanocene compounds on magnesium or silica compounds. . However, to date, metallocene catalysts require complex organometallic chemical synthesis and use expensive methylaluminoxane (MAO) or boron compounds as cocatalysts in the polymerization of olefins. The polymers produced by metallocene catalysts have a narrow molecular weight distribution (Mw / Mn = 2 to 5), which has disadvantages in terms of processing of the polymers.

Recently, efforts have been made to develop catalysts that produce polymers with narrow molecular weight distributions that are not difficult to synthesize, such as metallocene compounds, by using bidentate or tridentated chelate compounds. have. Japanese Laid-Open Patent Publication No. 63-191811 discloses a result of polymerizing ethylene and propylene using a compound in which a halide ligand of a titanium halide compound is substituted with a TBP ligand (6-tert butyl-4-methylphenoxy) as a catalyst component. Polymerization of ethylene and propylene using MAO as a promoter reported the formation of a high activity, high molecular weight polymer (average molecular weight = 3,600,000 or more). U.S. Patent No. 5,134,104 discloses a catalyst for olefin polymerization using a dioctylaminetitanium halide {(C ₈ H ₁₇ ) ₂ NTiCl ₃ } compound as a catalyst component in which a halide ligand of TiCl ₄ is replaced with a bulky amine ligand. J. Am. Chem. Soc. No. 117, page 3008, is a chelate compound capable of limiting the steric space of transition metals, and has a 1,1'-bi-2,2'naphthoxy ligand (1,1'-bi-2) on a titanium or zirconium transition metal. , 2'-naphthol) and a catalyst for olefin polymerization using a chelate-linked compound and derivatives thereof are disclosed. Japanese Unexamined Patent Publication Nos. 6-340711 and 0606125A2 disclose halide ligands of titanium halide and zirconium halide compounds. A catalyst for chelating olefin polymerization has been disclosed which is substituted with chelated phenoxy groups to produce polymers of high molecular weight and narrow molecular weight distribution.

Recently, a catalyst for olefin polymerization using an amine-based chelate transition metal compound has attracted attention. Organometallics 1996, Vol. 15, p. 2672 and Chem. Commun. 1996, p.2623 introduces an example of synthesizing a titanium compound chelate-bonded with various types of diamide compounds and utilizing them as catalysts for olefin polymerization. J. Am. Chem. Soc., 1998, Vol. 120, p. 8640, introduces propylene polymerization using titanium compounds and zirconium compounds chelate bound by diamide. Organometallics 1998, Vol. 17, p.4795, introduce a catalyst for the polymerization with titanium or zirconium chelated by [(ArylNCH ₂ CH ₂ ) ₂ O] and [(ArylNCH ₂ CH ₂ ) ₂ S], Organometallics 1998, Vol. . 17, p.4541 introduces catalysts for olefin polymerization using titanium, vanadium and chromium compounds chelate bonded by [N, N-diphenyl-2,4-pentanediimine] ligands. See also J. Am. Chem. Soc., 1996, Vol. 118, p. 10008, a titanium compound chelate-bonded by (ArylNCH ₂ CH ₂ CH ₂ NAryl) is introduced as a catalyst for olefin polymerization.

However, the catalyst for olefin polymerization using the chelated titanium and zirconium compounds described above has only been introduced as a homogeneous catalyst, and in order to improve the particle properties of the produced polymer, it is supported on the inorganic carrier or on the inorganic carrier. There have been no reports on the copolymerization characteristics of alpha-olefins or non-homogeneous catalysts that are activated by the catalysts. Most of the reported chelate compounds have the disadvantage of using expensive MAO as a promoter.

An object of the present invention is to provide a new catalyst for olefin polymerization, which is a liquid titanium compound chelate-bonded by imidazole-based ligand, and narrow molecular weight by using the catalyst as a main catalyst in the presence of a separate magnesium halide compound and an organometallic aluminum compound. It is to provide an olefin polymerization method having a distribution and producing a uniform branch in the polymer chain.

The present invention relates to a novel olefin polymerization chelate catalyst composed of a liquid titanium compound bonded by an imidazole series chelate ligand, and an olefin polymerization method using the same.

The catalyst for olefin polymerization according to the present invention is a liquid chelated titanium compound, which is Mg [Al (OR) ₃ R ′] ₂ containing magnesium and aluminum as shown in the following scheme (I), wherein R and R ′ Is a compound of the alkyl group) to form a chelate ligand-containing magnesium compound by reacting with an imidazole-based chelating ligand, and then reacted with a titanium halide compound to prepare a liquid titanium compound, thus preparing a liquid titanium compound It is prepared by reacting Mg [Al (OR) ₃ R ′] ₂ once again.

Scheme (Ⅰ)

Mg [Al (OR) ₃ R ′] ₂ + imidazole series chelate ligand --- → chelate ligand

Yu Magnesium Compound

Chelated Ligand-containing Magnesium Compounds + Titanium Halide Compounds-→ Liquid

Titanium compound

Liquid Titanium Compound + Mg [Al (OR) ₃ R ′] _2- → Liquid Chelated Titanium Compound

Compounds of the Mg [Al (OR) ₃ R ′] ₂ form containing magnesium and aluminum used in the preparation of the catalyst of the present invention are general organometallic aluminum compounds of the AlR ″ ₃ form, as represented by Scheme (II) below. The ROH-type alcohol is reacted to prepare an aluminum alkoxy compound in the form of Al (OR) ₃ , and then a Grignard reagent in the form of R ′ ₂ Mg is reacted with the aluminum alkoxy compound in the form of Al (OR) ₃ .

Scheme (II)

AlR ″ ₃ + 3ROH-→ Al (OR) ₃ + 3R ″ H

R ′ ₂ Mg + 2Al (OR) _3- → Mg [Al (OR) ₃ R ′] ₂

(Where R, R ′ and R ″ are alkyl groups)

The reaction between AlR ″ ₃ and ROH is preferably added dropwise at 0 to 10 ° C. as an exothermic reaction, and the reaction time is preferably maintained at room temperature for at least 1 hour after the addition. The reaction between R ' ₂ Mg and Al (OR) ₃ involves mild heat but does not require a particularly low temperature.

As the general organometallic aluminum compound of the AlR ″ ₃ form, triethylaluminum, trimethylaluminum, triisobutylaluminum, trioctylaluminum, etc. are preferred. As the alcohol of the ROH form, an alkyl group having 6 or more carbon atoms for controlling the heat of reaction is preferred. Alcohol is suitable. In addition to the Grignard compound of the R _'2 Mg forms such as dibutyl magnesium, butyl ethyl magnesium, butyl octyl magnesium it is preferred.

The reaction represented by Scheme (II) is a reaction proceeding very easily, and it is preferable to proceed at room temperature. As a reaction solvent, aliphatic hydrocarbons, such as hexane and heptane, are preferable.

Magnesium-containing chelate ligands by reaction of Mg [Al (OR) ₃ R ′] ₂ prepared by the reaction of Scheme (II) described above with an imidazole-based chelate ligand, as described in Scheme (I). The compound is prepared.

Since the imidazole-based chelate ligand is not dissolved in a nonpolar solvent such as hexane, it is dissolved in a solvent of ether such as THF to prepare a liquid solution. The reaction between the imidazole-based chelate ligand and Mg [Al (OR) ₃ R ′] ₂ proceeds smoothly, and the reaction temperature is preferably less than 50 ° C. at room temperature, which is a mild reaction condition, and the reaction molar ratio is 1: 1 to 1. A ratio of 1: 1.5 is preferred, and more preferably a ratio of 1: 1.1 is suitable. As for reaction time, 1-3 hours are suitable, and if it is 1 hour or more, it will fully react.

As the imidazole-based chelating ligand, compounds such as benzimidazole, imidazole, benzotriazole, and gramine or derivatives thereof are preferable.

The liquid titanium compound is prepared by reacting the chelate ligand-containing magnesium compound thus prepared with the titanium halide compound. That is, the chelated ligand-containing magnesium compound prepared above is added dropwise to the titanium halide compound at room temperature, and then reacted at 65 to 70 ° C. for at least 1 hour to prepare a liquid titanium compound. At this time, the molar ratio of magnesium and titanium is preferably 1: 1 or 1: 1.1. The liquid titanium compound thus prepared is not dissolved in a nonpolar solvent such as hexane, but only in a polar solvent such as ether.

However, when Mg [Al (OR) ₃ R ′] ₂ is reacted again, a liquid chelated titanium compound dissolved in a nonpolar solvent such as hexane is produced. That is, Mg [Al (OR) ₃ R ′] ₂ was reacted with the liquid titanium compound prepared above at a ratio of 1: 1 at room temperature for 3 hours or longer and at 40 to 50 ° C or longer for 1 hour, By removing the solvent and adding a nonpolar solvent such as hexane to the solid component from which the solvent was removed to separate the liquid chelated titanium compound dissolved in the nonpolar solvent such as hexane, and separating the solid that is not dissolved in the nonpolar solvent such as hexane. Throw it away. In addition, the reaction of the titanium halide compound with THF added to dissolve imidazoles when reacting with the titanium halide compound and the magnesium compound containing a chelate ligand is very violent. It is preferable to use.

Titanium halide compounds used to prepare the catalyst of the present invention include TiCl ₄ , TiBr ₄ , TiCl ₂ (OR) ₂ , TiCl ₃ (OR), TiBr ₂ (OR) ₂ , TiBr ₃ (OR), where R is an alkyl group Or an aryl group) such as a titanium compound containing at least two or more halide groups, and an ether-based electron donor is preferably diethyl ether, dibutyl ether, tetrahydrofuran (THF), and THF. Do.

The olefin polymerization method according to the present invention is carried out using a main catalyst component consisting of a liquid titanium compound chelated by an imidazole chelate ligand prepared as described above, an inorganic compound component including a cocatalyst component and magnesium halide. do.

As the cocatalyst component, a general organometallic aluminum compound in the form of R _n AlX _3-n (wherein R is an alkyl group, X is a halogen and n is 1, 2 or 3) is used, and the chelated liquid phase is a catalyst of the present invention. The titanium compound does not form a solid by a reduction reaction with a general organometallic aluminum compound used as a cocatalyst during the polymerization reaction, and thus the polymerization reaction may be made more uniform.

As the inorganic compound component containing the magnesium halide used in the olefin polymerization method of the present invention, a solid inorganic compound containing a magnesium halide component in silica having excellent particle properties can be used, which can be produced by a known method. That is, by reacting a solution in which a magnesium halide compound is dissolved in a hydrocarbon solution in the presence of an electron donor such as alcohol with a compound capable of reacting with an alkoxy group of the alcohol on the silica surface, the alcohol is removed so that the magnesium halide of the solid component precipitates on the silica surface. It can be manufactured by the method. For example, in US Pat. No. 5,155,078, an alkylaluminum compound is reacted with silica (F952) dried at 200 ° C. for at least 6 hours to coat an aluminum compound having a reducing ability on the silica surface, and magnesium halide is added to an alcohol and hydrocarbon solution. A method for producing silica containing magnesium halides has been reported by a method in which an aluminum compound having a reducing ability reacts with an alcohol by reacting a dissolved solution and a magnesium halide component of a solid component is contained on a silica surface. Alternatively, the magnesium halide compound produced by reacting the Grignard compound with an alkyl halide or silicon halide compound on the silica surface may be prepared by a method in which the surface of the silica is contained.

According to the olefin polymerization method of the present invention, in the presence of an inorganic compound component containing magnesium halide by using a liquid titanium compound of a liquid activated in advance by mixing the liquid chelated titanium compound component of the present invention as a main catalyst with the cocatalyst component An olefin polymerization reaction takes place.

According to the present invention, the red chelated titanium compound component is changed into a green liquid component by the reduction reaction when the liquid chelated titanium compound component and the promoter component are mixed, but a solid component is not produced by the reduction reaction. It is characterized by.

The polymer polymerized by the catalyst for olefin polymerization prepared by the present invention is determined by the particle properties of the inorganic compounds containing magnesium halide compounds, for example Sylopol 5550 manufactured by Grace Davison, which has excellent particle properties. When the olefin is polymerized, the polymer having an apparent density of 0.37 to 0.40 and a spherical shape can be obtained. Higher activity can be obtained by reacting with a certain amount of cocatalyst component prior to entering the polymerization reaction in order to activate the magnesium halide on the silica surface more. When the polymerization the co-catalyst component is preferably used in a common organometallic aluminum compound represented by R _n AlX _3-n (R is an alkyl group, X is a halogen, n = 1,2 or 3). The molar ratio (Al / Ti) of Al in the cocatalyst to Ti in the main catalyst is preferably 10 to 50, and the polymerization temperature is preferably 40 to 90 ° C.

The catalyst for olefin polymerization prepared by the present invention is suitable for ethylene homopolymerization and copolymerization with alpha (α) olefins, and alpha olefins having 3 to 10 carbon atoms are suitable as alpha olefins. For example, alpha olefins of propylene, 1-butene, 1-pentene, 1-hexyne, 4-methyl-1-pentene, and 1-octene can be copolymerized with ethylene, and the weight ratio content of ethylene in copolymerization is at least 70%. It is preferable that it is above.

The catalyst for olefin polymerization according to the present invention is suitable for slurry or gas phase polymerization. Control of molecular weight size can be achieved through control of temperature and olefin pressure, control of hydrogen pressure, and the like.

The catalyst for olefin polymerization according to the present invention can obtain a polymer having a density and branch of 0.900 to 0.960 g / cm 3 and a narrow molecular weight distribution by ethylene polymerization during olefin polymerization in a gas phase process and a slurry process.

The present invention will be described in more detail with reference to the following examples.

Example 1

The hydrocarbon solvent used for preparing the catalyst was removed by distillation in the presence of sodium, and the halogenated hydrocarbon was distilled in the presence of calcium hydride to remove the water. All reactions for catalyst preparation were carried out in a nitrogen atmosphere.

[Preparation of Titanium Compound Chelated by Benzimidazole]

Dilute 400 mmol of AlEt ₃ (triethylaluminum) in a hexane solution to make 400 ml, place it in a 1 liter flask and keep the flask at room temperature with cool water at room temperature, and slowly add dropwise 1200 mmol of 2-ethylhexanol. A colorless transparent solution was prepared. It took 1 hour to add, and the gas was observed by the dropping. After the addition, the reaction was completed by stirring at room temperature for 1 hour. 200 ml of butyloctyl magnesium 1.0M heptane solution was added to the solution, followed by stirring for 1 hour. Mg [Al (OR) ₃ R '] ₂ containing magnesium and aluminum (where R = ethylhexyl and R' = butyloctyl) 680 ml of solution was prepared.

5.92 g of benzimidazole (50 mmol) was added to a 1-liter flask and dissolved in 100 ml of THF. Then, 170 ml of the Mg [Al (OR) ₃ R ′] ₂ solution prepared above was injected and stirred at 40 ° C. for 1 hour. A magnesium compound (A) containing a doazole ligand was prepared.

Meanwhile, 16.7 g of TiCl ₄ (THF) ₂ compound was prepared in a separate flask, and the magnesium compound (A) prepared above was injected thereto. After injection, the reaction was carried out at 40 ° C. for 1 hour to prepare a red titanium compound (B). 170 ml of the Mg [Al (OR) ₃ R ′] ₂ solution prepared above was added thereto, followed by stirring at 50 ° C. for 3 hours. The reaction produced a red solution and the solvent was removed by reduced pressure. After removing the solvent, 500 ml of hexane was injected into the oily compound, stirred at room temperature for 6 hours, and then stirred for 20 minutes. The white solid subsided at the bottom. The red solution of the upper layer was separated from the white solid at the bottom. The reaction mixture was transferred to another flask and used as a liquid main catalyst component to carry out the polymerization reaction.

[Ethylene polymerization reaction]

After 1000 ml of hexane as a polymerization solvent was added to a 2 liter autoclave, which was sufficiently nitrogen-substituted at room temperature, nitrogen in the autoclave was replaced with ethylene. This solution was injected by reacting 5 ml of the main catalyst component prepared above at room temperature with 5 mmol of AlEt ₃ for 30 minutes. At this time, no generation of solids occurred. 0.5 g of sylopol 5550 (Grace Davision Co., Ltd., magnesium halide-containing silica) was added to the flask, and 2.5 mmol of AlOCt ₃ (trioctyl aluminum) was injected to inject the solution. Hydrogen was added at 1 Kg / cm 2 at 60 ° C., pressurized with ethylene to maintain a total pressure of 6 Kg / cm 2, and the temperature was raised to 70 ° C., and polymerization proceeded for 1 hour. The polymerized polymer was separated from hexane and dried. The polymerization results are shown in Table 1. As a result of the polymerization, 150 g of polyethylene was recovered, and a polymer having a narrow molecular weight distribution was obtained with a polymer (MI / 10 g) of 0.5 and an MFRR of 24.1.

[Ethylene / 1-Hexine Copolymerization Reaction]

A vacuum pump was connected to a 2 liter autoclave to remove oxygen and moisture and filled with ethylene gas. The vacuum pump connection and ethylene gas purge were repeated three more times to purge the reactor interior with ethylene gas. 900 ml of hexane as a polymerization solvent was injected, and 90 ml of 1-hexine was added thereto, followed by stirring for 10 minutes. 5 ml of the main catalyst component prepared above was reacted with 5 mmol of AlEt ₃ for 30 minutes at room temperature to form a green liquid, and this solution was injected. At this time, no generation of solids occurred. 0.5 g of sylopol 5550 silica was added to the flask, and 2.5 mmol of AlOCt ₃ was injected to inject a solution reacted for 1 hour. Hydrogen was added at 1 Kg / cm 2 at 60 ° C., pressurized with ethylene to maintain a total pressure of 7 Kg / cm 2, and the temperature was raised to 85 ° C. and polymerization proceeded for 30 minutes. After polymerization, the reaction was stopped by adding an ethanol solution, and the polymer was separated by adding an acidic alcohol solution. The isolated polymer had a MI of 0.45 and an MFRR of 23.1. The characteristics of the separated polymer are shown in Table 2, and as shown in Table 2, it can be seen that the molecular weight distribution is narrow from the small MFRR value, and that the composition of the copolymer is low because the melting point of the polymer containing the same amount of copolymer is low. It can be seen that the distribution is uniform.

Example 2

Titanium compound component chelated by imidazole was synthesized in the same manner as in Example 1 using imidazole instead of benzimidazole. The polymerization and copolymerization reaction proceeded in the same manner as in Example 1. The polymerization results are shown in Table 1, and the copolymerization results are shown in Table 2.

Example 3

Titanium compound components chelated by benzotriazole were synthesized in the same manner as in Example 1 using benzotriazole instead of benzimidazole. Polymerization and copolymerization were carried out in the same manner as in Example 1. The polymerization results are shown in Table 1, and the copolymerization results are shown in Table 2.

Example 4

Using a gramine instead of benzimidazole, a titanium compound component chelated by gramine was synthesized in the same manner as in Example 1. The polymerization and copolymerization reaction proceeded in the same manner as in Example 1. The polymerization results are shown in Table 1, and the copolymerization results are shown in Table 2.

Comparative Example 1

[Production of Liquid Titanium Compound]

Dilute 100 mmol of AlEt ₃ in a hexane solution to make 100 ml, place it in a 1-liter flask to keep the flask at room temperature with cool water at room temperature, and slowly add 300 mmol of 2-ethylhexanol to form a colorless transparent solution. It was. It took 1 hour to add, and the gas was observed by the dropping. After the addition, the reaction was completed by stirring at room temperature for 1 hour. 50 ml of butyloctyl magnesium 1.0M heptane solution was added to the solution, followed by stirring for 1 hour. Mg [Al (OR) ₃ R ′] ₂ containing magnesium and aluminum (where R = ethylhexyl and R '= butyloctyl) Was prepared. The prepared Mg [Al (OR) ₃ R ′] ₂ solution was reacted with 16.7 g of TiCl ₄ (THF) ₂ (50 mmol) at room temperature for 6 hours. By reaction, the TiCl ₄ (THF) ₂ solid, which was initially light yellow, gradually turned brown, producing a white magnesium halide solid. After stirring at room temperature for 6 hours, the stirring was stopped and waited for 20 minutes. The white solid subsided at the bottom. The brown solution of the upper layer was separated from the white solid at the bottom and used as a liquid titanium compound component.

[Ethylene polymerization reaction]

Ethylene polymerization and copolymerization were carried out in the same manner as described in Example 1 except for using the liquid titanium compound component, which is the catalyst component prepared above, and the polymerization results are shown in Tables 1 and 2.

According to the above results, since the MFRR of the polymer polymerized according to the present invention is 23-25, which is smaller than 29 of the comparative example, the polymer has a narrow molecular weight distribution and the Tm of the polymer having the same content of C6 branch is 121-123 占 폚. It can be seen that because it is lower than the Tm (125 ° C.) in the example, it produces a copolymer in which branches are more uniformly distributed in the polymer chain.

As described above, an olefin (co) polymer having a narrow molecular weight distribution and a branch formed in the polymer chain can be obtained by the catalyst for olefin polymerization of the present invention.

Claims (4)

Methyl [Al (OR) ₃ R '] ₂ (where R and R' are alkyl groups) is reacted to form a chelate ligand-containing magnesium compound, followed by reaction with a titanium halide compound. To produce a liquid titanium compound, and reacting the liquid titanium compound with a Mg [Al (OR) ₃ R ′] ₂ compound to produce a liquid chelating catalyst for olefin polymerization. The chelating catalyst for liquid olefin polymerization according to claim 1, wherein the imidazole-based chelating ligand is benzimidazole, imidazole, benzotriazole, gramine or a derivative thereof. Magnesium halide is contained by using the catalyst according to claim 1 as a main catalyst and using an organometallic aluminum compound in the form of R _n Cl _3-n Al (R is an alkyl group, n = 1, 2 or 3) as a cocatalyst. Process for the polymerization of olefins, characterized in that carried out in the presence of silica. 4. The polymerization method of olefin according to claim 3, wherein the main catalyst and the cocatalyst are mixed in advance and injected into a liquid form.