KR100619153B1 - Catalyst for producing polyolefin having broad molecular weight distribution and method for producing polyolefin using the same - Google Patents

Abstract

The present invention relates to a catalyst for producing a polyolefin having a broad molecular weight distribution and a method for producing a polyolefin using the same, and more particularly, a transition metal of Group IV, V, or VI of a periodic table containing at least two phenoxy ligands. The trivalent trivalent periodic table including the phenoxy clock ligand obtained by reducing the compound to a trivalent transition metal compound using an organomagnesium compound, and then supporting an additional tetravalent titanium compound on the resultant group The present invention relates to a catalyst for producing a polyolefin having a broad molecular weight distribution and a method for producing a polyolefin using the same, comprising a Group V or VI transition metal compound and a tetravalent titanium compound. According to the present invention, there is provided a Ziegler-Natta catalyst for producing a polyolefin having a higher polymerization activity than a conventional trivalent transition metal compound catalyst, and a method for producing a polyolefin having a broad molecular weight distribution with high activity using the same.

Molecular weight distribution, polyolefin, catalyst

Description

Catalyst for producing polyolefin with broad molecular weight distribution and polyolefin manufacturing method using same {CATALYST FOR PRODUCING POLYOLEFIN HAVING BROAD MOLECULAR WEIGHT DISTRIBUTION AND METHOD FOR PRODUCING POLYOLEFIN USING THE SAME}

The present invention relates to a catalyst for producing a polyolefin having a broad molecular weight distribution and a method for producing a polyolefin using the same, and more particularly, a transition metal of Group IV, V, or VI of a periodic table containing at least two phenoxy ligands. The trivalent trivalent periodic table including the phenoxy clock ligand obtained by reducing the compound to a trivalent transition metal compound using an organomagnesium compound, and then supporting an additional tetravalent titanium compound on the resultant group The present invention relates to a catalyst for producing a polyolefin having a broad molecular weight distribution and a method for producing a polyolefin using the same, comprising a Group V or VI transition metal compound and a tetravalent titanium compound.

In the olefin polymerization reaction using a transition metal compound as a catalyst, a process for producing an ethylene polymer and an ethylene copolymer using a trivalent Group IV transition metal compound is described in US Pat. No. 4,894,424. In this U.S. patent, a transition metal compound of group IV, V and VI whose oxidation value is at least tetravalent, for example titanium having a structure of Ti (OR) _m Cl _n (here n + m = 4) The catalyst is prepared by a reduction reaction of the compound with a Grignard compound having a structure of RMgCl (here, R is an alkyl group) made of magnesium (Mg) and alkyl chloride (RCl). Since this catalyst is a catalyst produced by a reduction reaction with a Grignard compound, at least 80% of the titanium metal contained in the catalyst is present in a trivalent oxidation value (Ti ³⁺ ). In US Pat. No. 4,894,424, an alkoxy ligand was used as the ligand to be introduced into the titanium compound.

On the other hand, phenoxy compounds have recently been mainly used for nonmetallocene catalysts. J. Am. Chem. Soc No. 117, No. 3008, a compound in which a 1,1'-bi-2,2'-naphthoxy ligand (1,1'-bi-2,2'-naphthol) is bound to a titanium or zirconium transition metal. And catalysts for producing polyolefins using the derivatives thereof have been reported, and in Japanese Patent Laid-Open Nos. Hei 6-340711 and EP 0606125 A2, the substitution of halide ligands of titanium halides and zirconium halide compounds with chelated phenoxy groups Catalysts for the production of chelated polyolefins have been reported that can produce polymers of high molecular weight and narrow molecular weight distribution. On the other hand, in US Pat. No. 1569, 5069 and No. 1562, a catalyst system for ethylene polymerization using a titanium compound having a bisphenol-based ligand as a main catalyst and a MAO as a catalyst has been reported.

However, the catalyst for preparing non-metallocene-based polyolefins using chelated titanium and zirconium compounds as described above has the disadvantage of using expensive MAO or boron compounds as cocatalysts. In this case, the two phenoxy groups are limited to a structure in which they are connected to each other, thereby limiting the width of the application.

On the other hand, in Organometallics No. 17, page 3138 and No. 18, 2557, examples of the use of two molecules of phenoxy compounds as catalysts for the synthesis of compounds substituted with titanium halides and Diels-Alder reactions are reported. However, Ziegler-Natta catalysts for preparing polyolefins in chelated form of two molecules of phenoxy compounds have not been reported.

The present invention introduces a phenoxy ligand, which has been used only for the preparation of a catalyst for the Diels-Alder reaction as described above, into an transition metal compound having an oxidation value of 4 or more, and reduced it to an organic magnesium compound. And then supported on the resulting product, a new Ziegler-Natta catalyst for producing a polyolefin obtained by further supporting a tetravalent titanium compound and a higher molecular weight distribution than the conventional trivalent Group IV transition metal compound catalyst by using the same. It is an object to provide a process by which polyolefins can be prepared.

According to the present invention, an oxide comprising at least two phenoxy clock ligands is supported by reducing the transition metal compound of Group IV, Group V, or Group VI of at least 4 to a trivalent transition metal compound using an organomagnesium compound. An oxide comprising a trivalent periodic table IV, V or VI transition metal compound containing a phenoxy ligand, and a tetravalent titanium compound oxidized, obtained by further supporting a tetravalent titanium compound on the resultant product. Ziegler-Natta catalysts for the production of polyolefins are provided.

The oxidized trivalent periodic table group IV, group V or group VI transition metal compound containing the phenoxy clock ligand contained in the Ziegler-Natta catalyst for producing polyolefin of the present invention is as shown in Scheme 1 below as an example. , M (OAr) _n X _an (wherein M is a Group IV, V or VI transition metal of the periodic table, Ar is a C ₆ to C ₃₀ substituted or unsubstituted aryl group, X is a halogen atom, n is an integer or a fraction satisfying 2 ≦ n ≦ a, and a is an oxidation or tetravalent periodic table group IV, group V, in which at least two phenoxyglycol ligands having a structure of a structure of oxidation) are introduced. Or by reducing the Group VI transition metal compound into an organomagnesium compound.

Scheme 1

Ti (OAr) _n Cl _4-n + RMgX → Ti (OAr) _n-1 Cl _4-n

In Scheme 1, Ar is a C ₆ ~ C ₃₀ substituted or unsubstituted aryl group, R is a C ₁ ~ C ₁₆ alkyl group, X is a halogen atom, n is an integer satisfying 2≤n≤4 Or fraction.

In the Ziegler-Natta catalyst for producing polyolefin of the present invention, a transition metal which can be reduced by an organomagnesium compound among the transition metals used in the Ziegler-Natta-based catalysts already known as the Group IV, V, or VI catalyst of the periodic table. Metals are usable, with titanium being preferred.

In the Ziegler-Natta catalyst for producing polyolefin of the present invention, in order to introduce the phenoxy clock ligand into the transition metal compound, for example, 2,6-diisopropylphenol, 2-methyl-6-butylphenol, 2-butyl Substituted or unsubstituted phenoxy compounds of C ₆ to C ₃₀ , such as -6-butylphenol, can be used, of which 2,6-diisopropylphenol is preferably used.

The organomagnesium compound used in the preparation of the Ziegler-Natta catalyst for producing polyolefin of the present invention is a compound having a structure of R _m MgX _2-m , wherein R is an alkyl group having 1 to 16 carbon atoms, preferably 2 to 8 carbon atoms. , X is a halogen atom, and m is an integer or fraction satisfying 0 <m ≦ 2.

As said oxidation tetravalent titanium compound contained in the Ziegler-Natta catalyst for polyolefin manufacture of this invention, titanium tetrahalide can be used preferably, and titanium tetrachloride is especially preferable.

According to one preferred embodiment of the present invention, the Ziegler-Natta catalyst for producing polyolefin of the present invention may be prepared by the following method.

First, the Group IV, Group V, or Group VI transition metal compound in which at least two phenoxy ligands are introduced is oxidized, for example, an excess of a phenoxy compound and titanium tetrachloride in the presence of n-butyllithium. By reaction.

The Ziegler-Natta catalyst for producing polyolefins of the present invention has a temperature of -20 ° C to 150 ° C, more preferably 60 ° C to 90 ° C, in the presence of an aliphatic hydrocarbon such as heptane and optionally an electron donor such as tetrahydrofuran, ether or the like. Under the conditions, an oxidation of at least two phenoxy ligands introduced is carried out by reducing the transition metal compound of Group IV, Group V, or Group VI of the periodic table at least 4 with an organomagnesium compound, and then adding a tetravalent titanium oxide compound to the resultant. It can be prepared by further supporting.

Aliphatic hydrocarbons used in the preparation of the catalyst of the present invention include hexane, heptane, propane, isobutane, octane, decane, kerosene and the like, with hexane or heptane being particularly preferred. In addition, usable electron donors include methyl formate, ethyl acetate, butyl acetate, ethyl ether, tetrahydrofuran, dioxane, acetone, methyl ethyl ketone, and the like, particularly tetrahydrofuran or ether.

Oxidation of at least two phenoxy ligands introduced with a tetravalent or higher periodic table of Group IV, Group V or Group VI and the organomagnesium compound is carried out in the presence of an alkyl halide having 1 to 16 carbons. desirable.

The organomagnesium compound used as the reducing agent has a structure of RMgX or MgR ₂ (wherein R is a C ₁ to C ₁₆ , preferably a C ₂ to C ₈ alkyl group and X is a halogen atom), and after Phenoxy clock ligands can be used for the reaction with the introduced transition metal compound. In addition, the organomagnesium compound may be used in the form of a complex with an electron donating compound such as ether or the solvent used, if necessary.

In preparing the catalyst of the present invention, it is preferable that the compounds are used in the following molar ratios in view of the efficiency of the catalyst production process and the improvement of the polymerization activity.

0.1 ≦ (transition metal compound having at least two phenoxy clock ligands introduced) /RMgX≦0.5, and 1 ≦ alkyl halide / RMgX ≦ 2; or

0.1 ≦ (transition metal compound having at least two phenoxy clock ligands introduced) / MgR ₂ ≦ 0.5, and 2 ≦ alkyl halides / MgR ₂ ≦ 4; And

1.5 ≤ (transition metal compound having at least two phenoxy ligands introduced) / tetravalent titanium oxide ≤ 15

According to another embodiment of the present invention, the catalyst of the present invention is -20 ° C to 150 ° C, more preferably 60 ° C to 90 ° C in the presence of aliphatic hydrocarbons and / or electron donors without prior preparation of organomagnesium compounds Under the temperature condition of ℃, the oxidation of the metal magnesium, at least two phenoxy ligands introduced with the tetravalent or more periodic table Group IV, Group V or Group VI transition metal compound and the alkyl halide after reacting the resultant It can be prepared by further supporting the titanium compound. In this case, it is understood that the organomagnesium compound, which is a reducing agent, reacts with the transition metal compound into which at least two phenoxy ligands are introduced while being produced during the reaction in which the catalyst is prepared. In this case, it is preferable that the compounds are used in the following molar ratios in view of the efficiency of the catalyst production process and the improvement of the polymerization activity.

0.1 ≦ (transition metal compound having at least two phenoxy ligands introduced) /Mg≦0.5, and

0.5 ≦ alkyl halide / Mg ≦ 10, more preferably 1 ≦ alkyl halide / Mg ≦ 2; And

1.5 ≤ (transition metal compound having at least two phenoxy ligands introduced) / tetravalent titanium oxide ≤ 15

According to another aspect of the present invention, an oxidation comprising at least two phenoxy clock ligands as a main catalyst is carried out by reducing a tetravalent or more periodic table of Group IV, Group V, or Group VI transition metal compounds, and the resulting oxidation is 4 A Ziegler-Natta catalyst for producing polyolefins, wherein the oxidation comprises a trivalent periodic table of Group IV, Group V, or VI transition metal compounds comprising a phenoxy clock ligand and the oxidation tetravalent titanium compound, obtained by further supporting a valent titanium compound; and Also provided is a method of preparing polyolefins using organometallic compounds of Group II or III of the Periodic Table as cocatalysts.

In the polyolefin production method of the present invention, the Ziegler-Natta catalyst for producing polyolefin of the present invention as described above is used as the main catalyst.

In the polyolefin production method of the present invention, an organometallic compound of a Group II or Group III metal of the periodic table is used as the promoter, and an organoaluminum compound such as trialkylaluminum is preferably used. The alkyl group included in the organometallic compound of Group II or III of the Periodic Table used as a promoter in the polyolefin production method of the present invention contains 1 to 16 carbon atoms, preferably 2 to 12 carbon atoms. Examples of such an organoaluminum compound include triethyl aluminum, trimethyl aluminum, trinormal propyl aluminum, trinormal butyl aluminum, triisobutyl aluminum, trinormal hexyl aluminum, trinormal octyl aluminum, tri-2-methylpentyl aluminum, and the like. Preferred examples thereof include triethyl aluminum, trinormal hexyl aluminum and trinormal octyl aluminum.

In the polyolefin production method of the present invention, the use ratio of the main catalyst and the cocatalyst may vary depending on the characteristics of each polymerization process and the desired polymer properties, and in the slurry process, the gas phase process, or the solution process, the periodic table in the promoter It is preferable to use the main catalyst and the cocatalyst in an amount such that the Group II or III metal) / (transition metal in the main catalyst) is in a molar ratio in the range of 0.5 to 500 in terms of improving the efficiency of the polymerization process and the polymerization activity. Do.

According to one embodiment of the invention, in the polyolefin production process of the invention, the polymerization is generally carried out at a pressure of 15 bar or less and a temperature of 40 ℃ to 150 ℃. The polymerization is carried out by introducing monomers composed of ethylene or possibly other olefins into a liquid diluent, such as saturated aliphatic hydrocarbons in which the catalyst system is present, and when no diluent is used, the gaseous monomers are contacted directly with the catalyst system. Is performed. The polymerization can generally be carried out in the presence of a chain growth inhibitor such as hydrogen.

In the polyolefin production method of the present invention, the catalyst system may also be configured in various ways. For example, the main catalyst is introduced directly into the reactor in the form of a solid or in the form of a prepolymer prepared by prepolymerization of one or more olefins in an inert liquid such as an aliphatic hydrocarbon. May be Organometallic compounds of Group II or III of the periodic table, which are cocatalysts, can be added directly to the polymerization reactor.

Hereinafter, the present invention will be described in more detail with reference to Examples and Comparative Examples, but the scope of the present invention is not limited thereto.

Example 1

1. Preparation of catalyst

Into a 5-liter four-necked flask equipped with a mechanical stirrer, 47.8 g (1.97 mol) of magnesium metal and 5.0 g (0.197 mol) of iodine were added, and 2400 ml of purified hexane was added and suspended. The temperature of this suspension mixture was raised to about 70 ° C., 88.8 g (0.188 mol) of bis (2,6-diisopropylphenoxy) titanium dichloride was dissolved in 150 ml of hexane, and injected into 317.8 ml of 1-chlorobutane ( 3.048 mole) was added dropwise at a constant rate. After completion of the dropwise addition, the reaction was further performed for 2 hours, and then 5 ml (0.042 mol) of titanium tetrachloride was injected, followed by an additional reaction of 1 hour to prepare a catalyst. The prepared catalyst was washed four times with sufficient hexane and then stored as a slurry in purified hexane. The results of the component analysis in the catalyst slurry are as follows:

Total titanium: 3.8wt%,

Trivalent Titanium Oxide: 75% of total titanium

2. Olefin Polymerization

1000 ml of purified hexane was injected into a 2 L stainless steel reactor equipped with a stirrer and a heating / cooling device. The reactor was thoroughly washed with pure nitrogen before use. Next, 2 cc of 1.0 M concentration of hexane dilute solution of trinomal octyl aluminum (TnOA) was injected into the reactor as a cocatalyst, and the catalyst slurry prepared in step 1 was prepared as a slurry having a Ti concentration of 6 mM as the main catalyst. 4.5 ml Ti slurry was injected into the reactor. Subsequently, the reactor temperature was raised to 80 ° C., hydrogen was supplied at a pressure of 66 psig, ethylene was supplied so that the voltage of the reactor was 187 psig, and the reaction was started by stirring at 1000 rpm. During the reaction, the polymerization was carried out for 1 hour while supplying enough ethylene so that the voltage of the reactor was kept constant at 187 psig. After 1 hour of polymerization, about 10 cc of ethanol was injected to remove the catalytic activity to terminate the reaction to obtain a resultant polymer. The obtained polymer was separated by a filter and sufficiently dried to obtain 113.2 g of polyethylene.

Example 2

In the polymerization step of the olefin, polyethylene was prepared in the same manner as in Example 1, except that 2 cc of 1.0M concentration hexane diluent of triethylaluminum (TEA) was used as the cocatalyst. The amount of polyethylene obtained after drying was 102.1 g.

Comparative Example 1

1. Preparation of catalyst

Into a 5-liter four-necked flask equipped with a mechanical stirrer, 47.8 g (1.97 mol) of magnesium metal and 5.0 g (0.197 mol) of iodine were added, and 2400 ml of purified hexane was added and suspended. The temperature of this suspension mixture was raised to about 70 ° C, 108.59 g (0.203 mol) of bis (2,6-diisopropylphenoxy) titanium dichloride was dissolved in 150 ml of hexane, and injected into 317.8 ml of 1-chlorobutane ( 3.048 mole) was added dropwise at a constant rate. After completion of the dropwise addition, the reaction was carried out for 2 hours to prepare a catalyst. The prepared catalyst was washed four times with sufficient hexane and then stored as a slurry in purified hexane. The results of the component analysis in the catalyst slurry are as follows:

Total titanium: 3.56wt%,

Trivalent Titanium Oxide: 83% of total titanium

2. Olefin Polymerization

Polyethylene was prepared in the same manner as in Example 1 except that the catalyst slurry prepared in Step 1 of Comparative Example 1 was prepared as a main catalyst as a slurry having a Ti concentration of 6 mM, and 4.5 ml of this 6 mM-Ti slurry was used. It was. The amount of polyethylene obtained after drying was 73.0 g.

Comparative Example 2

1. Preparation of catalyst

To a 1 L four-necked flask equipped with a mechanical stirrer, 12.7 g (0.525 mol) of magnesium metal and 1.4 g (0.005 mol) of iodine were added, and 600 ml of purified heptane was added and suspended. The temperature of this suspension mixture was raised to about 70 ° C., 15.2 ml (0.056 mol) of titanium propoxide and 7.2 ml (0.065 mol) of titanium tetrachloride were added thereto, and 84.1 ml (0.8 mol) of 1-chlorobutane were added at a constant rate. Added dropwise. After completion of the dropwise addition, the reaction was carried out for 2 hours to prepare a catalyst. The prepared catalyst was washed four times with sufficient hexane and then stored as a slurry in purified hexane. The results of the component analysis in the catalyst slurry are as follows:

Total titanium: 8.24wt%,

Trivalent titanium oxide: 85% of total titanium

2. Olefin Polymerization

Polyethylene was prepared in the same manner as in Example 1, except that 4.5 ml of the 6 mM-Ti slurry was used after making the catalyst slurry prepared in Step 1 of Comparative Example 2 as a main catalyst, using a slurry of 6 mM Ti concentration. It was. The amount of polyethylene obtained after drying was 40.0 g.

Table 1 shows the analysis results for the polyethylene of Examples 1 to 3 and Comparative Example 1 obtained as described above.

Table 1 Polyethylene Analysis Results

Analysis item Polymerization activity Melt Index (2.16kg) Melt Index (21.6kg) Melt Flow Rate Ratio (MFRR) Example 1 11.70 1.02 43.03 43.89 Example 2 10.52 1.14 48.70 42.72 Comparative Example 1 7.52 1.18 45.8 38.81 Comparative Example 2 4.13 1.09 34.8 31.90

Note) Polymeric activity unit: kg-PE / [g-Ti x hour (hr) x pressure (atm)]

Melt index (2.16kg): measured according to ASTM D1238, 190 ℃, 10min, 2.16kg

Melt Index (21.6kg): Measured according to ASTM D1238, 190 ℃, 10min, 21.6kg

Melt Flow Rate Ratio (MFRR): Melt Index (21.6kg) / Melt Index (2.16kg)

As can be seen in Table 1, in Examples 1 and 2 of the present invention, at least two phenoxy ligands are introduced into a transition metal compound having an oxidation value of 4 or more, and reduced to an organomagnesium compound, followed by oxidation of 4 The Ziegler-Natta catalyst prepared by further supporting a valent titanium compound showed about 2.5 to 2.8 times increased polymerization activity upon ethylene polymerization than the catalysts prepared in Comparative Examples 1 and 2. In addition, in the molecular weight distribution, which is an important physical property in processability, according to Table 1 above, when ethylene is polymerized using the catalysts prepared in Examples 1 and 2 of the present invention, the melt flow rate ratio of the polymer (MFRR) ) Was found to be larger than Comparative Examples 1 and 2, which means that in Examples 1 and 2, polyethylene having a broader molecular weight distribution than that of the polymers of Comparative Examples 1 and 2 was obtained.

As described above, when the olefin is polymerized using the Ziegler-Natta catalyst for producing polyolefin of the present invention, an olefin polymer having a wide molecular weight distribution can be prepared with higher polymerization activity than a conventional trivalent Group IV transition metal compound catalyst. have.

Claims (8)

Oxidation comprising at least two phenoxy clock ligands is carried out by reducing and supporting a Group IV, Group V, or Group VI transition metal compound of the periodic table 4 or more using an organomagnesium compound, and then oxidizing the resultant. Ziegler-Natta for the production of polyolefins comprising an oxidized trivalent periodic table group IV, V or VI transition metal compound comprising a phenoxy clock ligand obtained by further supporting a tetravalent tetravalent titanium compound and a tetravalent titanium compound catalyst. The periodic table IV, V, or VI transition metal compound comprising at least two phenoxy ligands, wherein the transition metal compound is M (OAr) _n X _an (wherein M is a periodic table IV). Group, Group V or Group VI transition metal, Ar is a substituted or unsubstituted aryl group of C ₆ ~ C ₃₀ , X is a halogen atom, n is an integer or fraction satisfying 2≤n≤a, a Is an integer of 4 or more as the oxidation value of M) Ziegler-Natta catalyst for polyolefin production. The compound according to claim 2, wherein the organomagnesium compound has a structure of R _m MgX _2-m , wherein R is an alkyl group having 1 to 16 carbon atoms, X is a halogen atom, and m is 0 <m≤2. A Ziegler-Natta catalyst for producing polyolefins, characterized in that it is an integer or fraction. The oxidation reaction according to claim 2, wherein the oxidation reaction in which the at least two phenoxy ligands are introduced is a Group IV, V, or VI transition metal compound having a tetravalent or higher periodic table of -20 ° C to 150 ° C. Ziegler-Natta catalyst for polyolefin production, characterized in that carried out at a molar ratio of 0.1 ≦ (transition metal compound having at least two phenoxy ligands introduced) / organic magnesium compound ≦ 0.5. The Ziegler-Natta catalyst for producing polyolefin according to claim 1, wherein the tetravalent titanium compound is titanium tetrachloride. The molar ratio of the Group IV, Group V, or Group VI transition metal compound in which the at least two phenoxy clock ligands are introduced is a periodic table of Group IV, Group V or Group VI and the oxidation tetravalent titanium compound is 1.5 ≦ (at least two). A transition metal compound having a phenoxy clock ligand) / titanium oxide compound having a tetravalent oxide ≤ 15, Ziegler-Natta catalyst for producing polyolefin. A method for producing a polyolefin using a Ziegler-Natta catalyst according to any one of claims 1 to 6 as a main catalyst and an organometallic compound of group II or group III of the periodic table as a promoter. 8. The polyolefin according to claim 7, wherein the use ratio of the main catalyst to the promoter is in the range of 0.5 to 500 (mole ratio of Group II or Group III metal in the promoter) / (transition metal in the main catalyst) in molar ratio. Manufacturing method.