Method for producing catalyst for ethylene polymerization and method for producing ethylene polymer

Abstract

To provide a method for producing an ethylene polymerization catalyst which, in a chromium catalyst affording an ethylene polymer with a wide molecular weight distribution, yields an ethylene polymer containing an increased proportion of high-molecular-weight components.SOLUTION: There is provided a method for producing a catalyst for ethylene polymerization, which comprises the following steps: (1) supporting a chromium compound (b) on an inorganic oxide carrier (a), calcining and activating the resulting material in a non-reducing atmosphere to obtain a chromium catalyst (A); and (2) mixing the chromium catalyst (A), a reducing organic silicon compound (B), and an organic aluminum compound (C) in an inert hydrocarbon solvent.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a method for producing an ethylene polymerization catalyst and a method for producing an ethylene polymer. [Background technology]

[0002] Ethylene polymers and copolymers of ethylene and α-olefins, which contain ethylene as the main component (hereinafter, both polymers will be referred to as "ethylene-based polymers"), are widely used as resin materials for various molded products. The properties required of ethylene-based polymers vary depending on the molding method and application. For example, polymers with a relatively small molecular weight and narrow molecular weight distribution are suitable for products molded by injection molding, while polymers with a relatively large molecular weight and broad molecular weight distribution are suitable for products molded by film molding or blow molding.

[0003] By supporting any chromium compound on an inorganic oxide support such as silica and calcining it under a non-reducing atmosphere, hexavalent chromium species become the main component and exhibit polymerization activity. It is well known that the use of this catalyst (Phillips catalyst) can produce ethylene polymers with broad molecular weight distributions, and many products are produced using ethylene polymers obtained from Phillips catalysts. For this Phillips catalyst, techniques for controlling the shape of the molecular weight distribution have been established by controlling the physical structure of the silica support, adjusting the calcination temperature conditions, and blending other inorganic oxide supports (Non-Patent Document 1). However, in order to increase the molecular weight of the resulting ethylene polymers, it is necessary to reconsider the catalyst production steps, such as the selection of the raw material support and the calcination conditions.

[0004] Meanwhile, as techniques for controlling the molecular weight distribution of produced Phillips catalysts, there have been disclosed techniques for obtaining ethylene polymers with well-balanced physical properties using catalysts treated with specific organoaluminum compounds (Patent Document 1), and a technique for broadening the molecular weight distribution of the obtained polymers by coexisting a specific compound having a cyclopentadienyl ring (Patent Document 2). However, these techniques mainly change the molecular weight distribution due to a decrease in the molecular weight of the ethylene polymer. Therefore, there is a need for the development of an effective modifier for producing high-molecular-weight ethylene polymers using produced Phillips catalysts.

[0005] Because the main component of the Phillips catalyst is a hexavalent chromium species with a high oxidation state, it has long been known to use compounds such as carbon monoxide and nitrogen monoxide as reducing agents. This method shortens the induction time without changing the molecular weight distribution and can produce a highly active chromium catalyst, but the problem is that carbon monoxide and nitrogen monoxide are highly toxic compounds. On the other hand, it has been reported that hexavalent tungsten species can be reduced by treating a tungsten oxide catalyst, which promotes olefin metathesis reactions, with a specific organosilicon compound (2,3,5,6-tetramethyl-1,4-bis(trimethylsilyl)-1,4-diaza-2,5-cyclohexadiene) (Non-Patent Document 2).

[0006] Meanwhile, Patent Document 3 discloses a method for producing an ethylene polymer, which comprises polymerizing ethylene in the presence of a catalyst comprising (a) a solid obtained by supporting a chromium compound and an organosilicon compound on an inorganic oxide support and calcining the solid, and (b) a trialkylaluminum or alkylaluminum hydride. Patent Document 3 describes that the catalyst makes it possible to control the average molecular weight of the polymer produced by hydrogen, and shows that in an example in which an organosilicon compound is coexistent during calcination of the chromium compound, the average molecular weight decreases depending on the amount of hydrogen. In Patent Document 3, a chromium compound and an organosilicon compound are supported on an inorganic oxide support and then calcined under high-temperature conditions. Therefore, in the embodiment of Patent Document 3, the organosilicon compound is likely to be decomposed during high-temperature calcination, and the use of the organosilicon compound as a modifier for the chromium catalyst obtained after calcination is not intended. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] Patent No. 5460140 [Patent Document 2] Patent No. 4732444 [Patent Document 3] Special Publication No. 63-26121 [Non-patent literature]

[0008] [Non-Patent Document 1] Adv. Catal., 2010, 53, p.123-606. [Non-patent document 2] ACS Cent. Sci. 2016, 2, p.569-576. Summary of the Invention [Problem to be solved by the invention]

[0009] As described above, there is a demand for ethylene polymers having a relatively large molecular weight and a broad molecular weight distribution, and there is a need for the development of an effective modifier for obtaining ethylene polymers having an increased content of high molecular weight components from chromium catalysts produced. In view of the above-mentioned problems of the prior art, an object of the present invention is to provide a method for producing an ethylene polymerization catalyst that can give an ethylene polymer having an increased content of high-molecular-weight components by combining a chromium catalyst that can give an ethylene polymer having a broad molecular weight distribution with an effective modifier. [Means for solving the problem]

[0010] As a result of intensive research aimed at solving the above-mentioned problems, the present inventors have found that an ethylene polymer containing an increased amount of high molecular weight components can be produced by contacting a calcined chromium catalyst with an organosilicon compound having reducing properties and an organoaluminum compound (C) in an inert hydrocarbon solvent. Based on these findings, the present invention has been completed. That is, the present invention includes the following aspects.

[0011] [1] A method for producing an ethylene polymerization catalyst, comprising the following steps (1) and (2): Step (1): A step of supporting a chromium compound (b) on an inorganic oxide support (a) and calcining and activating the support in a non-reducing atmosphere to obtain a chromium catalyst (A). Step (2): A step of mixing the chromium catalyst (A), an organosilicon compound (B) having reducing properties, and an organoaluminum compound (C) in an inert hydrocarbon solvent. [2] The method for producing an ethylene polymerization catalyst according to [1] above, wherein the organosilicon compound (B) has a first ionization potential capable of reducing the chromium compound (b). [3] The method for producing an ethylene polymerization catalyst according to [1] or [2] above, wherein the organosilicon compound (B) has a first ionization potential of 5.5 to 8.0 eV. [4] The method for producing an ethylene polymerization catalyst according to any one of the above items [1] to [3], wherein the organosilicon compound (B) is an organosilicon compound represented by the following general formula (I), an organosilicon compound represented by the following general formula (IIA), an organosilicon compound represented by the following general formula (IIB), an organosilicon compound represented by the following general formula (IIIA), or an organosilicon compound represented by the following general formula (IIIB):

[0012] [ka] [In formula (I), R 1 , R 2 , R3 , R 4 , R 5 and R 6 are each independently a hydrogen atom, a halogen atom, a hydrocarbon group having 1 to 30 carbon atoms, or a substituent containing at least one heteroatom selected from the group consisting of an oxygen atom, a sulfur atom, a nitrogen atom, a phosphorus atom, and a silicon atom, or R 1 , R 2 , R 3 , R 4 , R 5 and R 6 may be bonded to each other to form a cyclic structure, and the hydrocarbon group may have a substituent containing a halogen atom or at least one heteroatom selected from the group consisting of an oxygen atom, a sulfur atom, a nitrogen atom, a phosphorus atom, and a silicon atom.

[0013] [ka] [In formula (IIA) and formula (IIB), R 11 , R 11’ , R 11” , R 12 , R 13 , R 14 , and R 15 are each independently a hydrogen atom, a hydrocarbon group having 1 to 14 carbon atoms, or an aromatic heterocyclic group having 4 to 14 carbon atoms.

[0014] [ka] [In formula (IIIA) and formula (IIIB), R 11 , R 11’ , R 11” , R 12 , R 13 , R 14 , R 15 , R 16 and R 17 are each independently a hydrogen atom, a hydrocarbon group having 1 to 14 carbon atoms, or an aromatic heterocyclic group having 4 to 14 carbon atoms.

[0015] [5] In the formula (I), R 1 , R 2 , R 3 , R 4 , R 5 and R 6 are each independently a hydrocarbon group having 1 to 6 carbon atoms, and in formula (IIA), formula (IIB), formula (IIIA), and formula (IIIB), R 11 , R 11’ , R 11” are each independently an alkyl group having 1 to 10 carbon atoms, and R 12 , R 13 , R 14 , R 15 are each independently a hydrogen atom or an alkyl group having 1 to 10 carbon atoms, and R 16 and R 17 The method for producing an ethylene polymerization catalyst according to any one of the above [1] to [4], wherein is a hydrogen atom. [6] The method for producing an ethylene polymerization catalyst according to any one of the above items [1] to [5], wherein the amount of the organosilicon compound (B) used in the step (2) relative to the chromium atoms contained in the chromium catalyst (A) is 0.001 to 100 in terms of a molar ratio ([B] / [Cr]).

[0016] [7] The method for producing an ethylene polymerization catalyst according to any one of the above items [1] to [6], wherein the organoaluminum compound (C) is at least one selected from the group consisting of an aluminum compound represented by the following general formula (1), an aluminum oxy compound represented by the following general formula (2-1), and an aluminum oxy compound represented by the following general formula (2-2): General formula (1): AlR 21 3 (In formula (1), R 21 are each independently an alkyl group, an alkoxy group, an aryloxy group, or a siloxy group, and may be the same or different from one another, and the aryloxy group may be substituted with an alkyl group, a halogen atom, an alkoxy group, or a nitrile group.

[0017] [ka] (In formulas (2-1) and (2-2), R 22 are each independently an alkyl group, an alkoxy group, an aryloxy group, or a siloxy group, and may be the same or different from one another, and the aryloxy group may be substituted with an alkyl group, a halogen atom, an alkoxy group, or a nitrile group. n represents an integer of 0 or more, and m represents an integer of 2 or more. [8] The organoaluminum compound (C) is In the general formula (1), R 21 At least one of R is an alkyl group having 1 to 6 carbon atoms, and 21 an aluminum compound represented by the general formula (1), wherein at least one of the above is an alkoxy group having 1 to 6 carbon atoms; In the general formula (2-1), R 22 are each independently an alkyl group having 1 to 6 carbon atoms, and an aluminum oxy compound represented by the general formula (2-1), In the general formula (2-2), R 22 is at least one selected from the group consisting of aluminum oxy compounds represented by general formula (2-2), each of which is independently an alkyl group having 1 to 6 carbon atoms. [9] The method for producing an ethylene polymerization catalyst according to any one of the above items [1] to [8], wherein in the step (2), a ratio of aluminum atoms in the organoaluminum compound (C) to chromium atoms contained in the chromium catalyst (A) is 0.1 to 100 as a molar ratio ([Al] / [Cr]).

[10] A method for producing an ethylene polymer, comprising: carrying out ethylene homopolymerization or copolymerization of ethylene and an α-olefin using an ethylene polymerization catalyst obtained by the method for producing an ethylene polymerization catalyst according to any one of the above items [1] to [9]; and using the ethylene polymerization catalyst in a non-reducing atmosphere without calcining it. [Effects of the Invention]

[0018] According to the present invention, it is possible to provide a method for producing an ethylene polymerization catalyst that gives an ethylene polymer with an increased content of high-molecular-weight components by combining an effective modifier with a chromium catalyst that gives an ethylene polymer with a broad molecular weight distribution. [Brief explanation of the drawings]

[0019] [Figure 1] FIG. 1 shows the results of UV-Vis-NIR measurement of each solid catalyst of the Examples and Comparative Examples. [Figure 2] FIG. 2 is a diagram showing the results of measuring the molecular weight distribution of the ethylene polymers produced in the examples and comparative examples. [Figure 3] FIG. 3 is a diagram showing the results of measuring the molecular weight distribution of the ethylene polymers produced in the examples and comparative examples. DETAILED DESCRIPTION OF THE INVENTION

[0020] The present invention will be described in detail below. In addition, unless otherwise specified, the notation "x to y" indicating a range means that x and y are included in the range.

[0021] I. Method for producing ethylene polymerization catalyst The method for producing an ethylene polymerization catalyst of the present invention is characterized by comprising the following steps (1) and (2): Step (1): A step of supporting a chromium compound (b) on an inorganic oxide support (a) and calcining and activating the support in a non-reducing atmosphere to obtain a chromium catalyst (A). Step (2): A step of mixing the chromium catalyst (A), an organosilicon compound (B) having reducing properties, and an organoaluminum compound (C) in an inert hydrocarbon solvent.

[0022] According to the method for producing an ethylene polymerization catalyst of the present invention, a chromium compound (b) is supported on an inorganic oxide support (a), which is then activated by calcination in a non-reducing atmosphere, and an organosilicon compound (B) having reducing properties and an organoaluminum compound (C) are mixed and contacted in an inert hydrocarbon solvent with a chromium catalyst (A), in which at least some of the chromium atoms are hexavalent, to produce an ethylene polymerization catalyst that gives an ethylene polymer having a broad molecular weight distribution and an increased amount of high-molecular-weight components. According to the present invention, by using an ethylene polymerization catalyst modified with a reducing organosilicon compound (B) and an organoaluminum compound (C) as modifiers in addition to a calcined chromium catalyst, it is possible to produce a polymer in which the balance of physical properties, such as moldability, strength, and rigidity, can be adjusted depending on the intended product by controlling the molecular weight distribution, particularly the proportion of the high molecular weight side.

[0023] The effects of the above combination in the production method of the present invention have not yet been elucidated, but can be estimated as follows. The reaction that occurs on the silica surface when a chromium compound is supported on the surface of an inorganic oxide support using silica as the inorganic oxide support (a) and chromium acetate as the chromium compound (b) and then activated by calcination is shown in Scheme 1 below. When silica and chromium acetate (aqueous solution) are mixed, the silanol groups in the silica react with the chromium acetate, resulting in the chromium acetate being supported on the silica. By calcining and activating this, the organic structure (acetic acid structure) is burned off and a chromate ester structure is formed, resulting in chromium catalyst (A) in which at least some of the chromium atoms are hexavalent.

[0024] [ka]

[0025] In a typical chromium catalyst, as shown in Scheme 2 below, when this chromate ester is mixed with ethylene, the chromate ester structure is reduced by ethylene to form an active site precursor. The time required for this reduction (the time it takes for the chromate ester to produce the active site precursor) is called the induction time. It is believed that after the chromium compound is supported on an inorganic oxide support, it is reduced to form the active site precursor, which then initiates ethylene polymerization.

[0026] [ka]

[0027] In contrast, in the method for producing an ethylene polymerization catalyst of the present invention, a chromium catalyst (A), in which at least some of the chromium atoms are hexavalent, is mixed with a reducing organosilicon compound (B) and an organoaluminum compound (C) in an inert hydrocarbon solvent before mixing with ethylene. In this case, as shown in Scheme 3 below, UV-Vis-NIR analysis results indicate that the chromate ester structure is reduced by the reducing organosilicon compound (B) to form divalent chromium species. It is believed that a disiloxane compound, a coordinating compound, is produced as a by-product during this process. It is believed that the coordinating compound acts on the catalytic active sites, resulting in an increase in high molecular weight components.

[0028] [ka]

[0029] In Scheme 3, hexamethyldisilane, which is a typical reducing agent and has the simplest structure among compounds having a silicon-silicon bond, is used as an example of the reducing organosilicon compound (B). However, it is understood that other reducing agents, such as compounds having a silicon-silicon bond, compounds having a silicon-nitrogen bond, or compounds having a silicon-carbon bond, can also form active site precursors in which a disiloxane compound is coordinated as a by-product when reducing hexavalent chromium.

[0030] In the present invention, the action of the reducing organosilicon compound (B) not only makes it possible to increase the high molecular weight component, but also the action of the organoaluminum compound (C) on the by-produced disiloxane compound is thought to have the effect of adjusting the influence of the disiloxane compound on the active species and the effect of acting on the active sites of the chromium catalyst to change the polymerization characteristics. One example is that by acting the organoaluminum compound (C) together with the organosilicon compound (B), the range of control of the molecular weight distribution can be expanded, such as by increasing the high molecular weight component as well as the low molecular weight component, and an ethylene polymerization catalyst can be produced that gives an ethylene polymer with a wide molecular weight distribution and an increased high molecular weight component.

[0031] 1.Process (1) Step (1) of the present invention is a step of supporting a chromium compound (b) on an inorganic oxide support (a) and calcining and activating the support in a non-reducing atmosphere to obtain a chromium catalyst (A).

[0032] [Inorganic oxide support (a)] The inorganic oxide support (a) used in the present invention may be any of the conventional inorganic oxide supports used in chromium catalysts, such as oxides of metals in Groups 2, 4, 13, or 14 of the periodic table. Specific examples include titania, zirconia, alumina, silica, magnesia, thoria, silica-titania, silica-zirconia, silica-alumina, silica-magnesia, and mixtures thereof, with silica being preferred. The preparation methods, physical properties and characteristics of supports suitable for the inorganic oxides of the present invention are described, for example, in the following documents: (i)CE Marsden, Preparation of Catalysts, Volume V, 215 pages, 1991, Elsevier Science Publishers (ii)CE Marsden, Plastics, Rubber and Composites Processing and Applications, Volume 21, 193 pages, 1994, Elsevier Science Publishers

[0033] The inorganic oxide support (a) according to the present invention preferably has a specific surface area of ​​100 m 2 / g~900m 2 / g is preferably 100m 2 / g~850m 2 / g, more preferably 150m 2 / g~850m 2 It is preferable to select the specific surface area so that it is 100 m / g. 2 / g~900m 2 When the molecular weight is in the range of 1 / g, the resulting ethylene polymer has a good balance between durability and impact resistance.

[0034] The pore volume of the inorganic oxide support (a) according to the present invention is preferably 0.5 cm 3 , similar to that of inorganic oxide supports used in general chromium catalysts. 3 / g~5.0cm 3 / g, more preferably 1.0 cm 3 / g~3.0cm 3 / g, more preferably 1.2 cm 3 / g~2.5cm 3 / g. 3 / g~5.0cm 3 When the amount of the inorganic oxide support is in the range of 0.15 wt. / g, the polymerization activity is good and the production of the inorganic oxide support is easy. The inorganic oxide support (a) according to the present invention preferably has an average particle size in the range of 10 μm to 200 μm, more preferably 20 μm to 150 μm, and even more preferably 30 μm to 100 μm.

[0035] [Chromium compounds (b)] The chromium compound (b) used in the present invention is preferably a compound in which at least some of the chromium atoms become hexavalent when supported on the inorganic oxide support (a) and then activated by calcination in a non-reducing atmosphere. Examples of such compounds include chromium oxide, chromium halides, chromium oxyhalides, chromates, dichromates, chromium nitrates, chromium carboxylates, chromium sulfates, chromium-1,3-diketo compounds, and chromate esters.

[0036] Specific examples include chromium(III) oxide, chromium trichloride, chromium chloride, potassium chromate, ammonium chromate, potassium dichromate, chromium nitrate, chromium sulfate, chromium acetate, tris(2-ethylhexanoate)chromium, chromium acetylacetonate, and bis(tert-butyl)chromate. Among these, chromium(III) oxide, chromium acetate, and chromium acetylacetonate are preferred. Even when chromium compounds having organic groups, such as chromium acetate and chromium acetylacetonate, are used, the organic groups are burned by calcination activation in a non-reducing atmosphere, as described below, and ultimately react with hydroxyl groups on the inorganic oxide support surface, as in the case of chromium(III) oxide. At least some of the chromium atoms become hexavalent and are immobilized in a chromate ester structure ((i) J. Phys. Chem. 1996, 100, 26, pp. 11062-11066; (ii) J. Mol. Catal. 1991, 66, pp. 59-71).

[0037] [Supporting chromium compound (b) on inorganic oxide support (a)] The chromium compound (b) is preferably supported on the inorganic oxide support (a) in a state in which at least some of the chromium atoms in the chromium compound are hexavalent, and is not particularly limited as long as this can be achieved, and can be carried out by known methods such as impregnation, solvent distillation, sublimation, etc., and an appropriate method may be used depending on the type of chromium compound used. The amount of the chromium compound to be supported, in terms of chromium atoms, is preferably 0.2 to 2.0 wt %, more preferably 0.3 to 1.7 wt %, and even more preferably 0.5 to 1.5 wt %, based on the support.

[0038] In the present invention, the chromium catalyst (A) in which the chromium compound (b) is supported on the inorganic oxide support (a) may further contain a fluorine compound. The method of incorporating a fluorine compound (fluorination) can be carried out by a known method, such as a method of impregnating a fluorine compound solution in a solvent and then distilling off the solvent, or a method of sublimating the fluorine compound without using a solvent, and a suitable method may be used depending on the type of chromium compound to be used. The chromium compound may be supported on the inorganic oxide support and then incorporated with the fluorine compound, or the chromium compound may be supported on the inorganic oxide support and then incorporated with the fluorine compound, but it is preferable to support the chromium compound and then incorporate the fluorine compound. The content of the fluorine compound is preferably 0.1 to 10% by weight, more preferably 0.3 to 8% by weight, and even more preferably 0.5 to 5% by weight, in terms of the content of fluorine atoms.

[0039] Examples of fluorine compounds that can be used include fluorine-containing salts such as hydrogen fluoride HF, ammonium fluoride NH4F, ammonium silicofluoride (NH4)2SiF6, ammonium borofluoride NH4BF4, ammonium hydrogen difluoride (NH4)HF2, ammonium hexafluorophosphate NH4PF6, and tetrafluoroborate HBF4. Of these, ammonium silicofluoride and ammonium hydrogen difluoride are preferred. From the viewpoint of uniformity, it is preferable to dissolve these in water or an organic solvent such as alcohol and then impregnate the chromium catalyst, but it is also possible to simply mix the solid with the chromium catalyst. When dissolving and impregnating, it is more preferable to use an organic solvent such as alcohol to suppress pore volume shrinkage due to surface tension. When a solvent is used, the solvent is removed and the material is dried by a known method such as air drying, vacuum drying, or spray drying.

[0040] By calcination activation (activation) in a non-reducing atmosphere (described later), these fluorine compounds are thermally decomposed to fluorinate the inorganic oxide support. For example, when silica is used as the inorganic oxide support and ammonium silicofluoride is used as the fluorine compound, the ammonium silicofluoride is thermally decomposed as follows to generate hydrogen fluoride HF and silicon fluoride SiF4. (NH4)2SiF6→ 2NH3+ 2HF + SiF4

[0041] Furthermore, it is known that HF ​​and SiF4 react with silanol groups on the silica surface to fluorinate them (see J. Mol. Catal. 1991, 66, pp. 59-71; A. Noshay et al., "Transition Metal Catalyzed Polymerizations - Ziegler·Natta and Metathesis Polymerizations," p. 396, 1988, Cambridge University Press). Si-OH + HF → Si-F + HO Si-OH + SiF4 → Si-O-SiF3 + HF 2Si-OH + SiF4→ (Si-O)2SiF2+ 2HF

[0042] Therefore, even if a solid fluorine compound such as a fluorine-containing salt is simply mixed with a chromium catalyst, the fluorine compound will eventually thermally decompose, causing a similar reaction to occur and fluorinating the chromium catalyst. Alternatively, a method in which the fluorine compound is added during the calcination activation (activation) step may be used. However, in this case, since the solid fluorine compound is fluidized in the gas, it is preferable to use a solid fluorine compound in the form of as fine particles as possible from the viewpoint of uniformity.

[0043] [Activation by firing in a non-reducing atmosphere] After the chromium compound (b) is supported on the inorganic oxide support (a), and optionally a fluorine compound is further supported, the support is subjected to calcination activation to obtain the chromium catalyst (A). The calcination activation is preferably carried out at a temperature of 300°C to 950°C, more preferably 325°C to 800°C, and even more preferably 350°C to 650°C. It is believed that the catalyst exhibits good performance in terms of polymerization activity when the calcination activation is carried out in the range of 300°C to 950°C. The calcination activation can be carried out in a non-reducing atmosphere substantially free of moisture, such as oxygen or air. An inert gas may also be present. Preferably, the calcination activation is carried out under a fluidized state using sufficiently dried air, such as by passing molecular sieves through the support, whereby at least a portion of the chromium atoms of the chromium compound supported on the inorganic oxide support are oxidized to hexavalent chromium and chemically fixed on the support. The valence of chromium can be roughly determined by visually observing the color change of the solid product (generally, hexavalent chromium is yellow to orange, trivalent chromium is green, and divalent chromium is blue).

[0044] 2.Process (2) Step (2) of the present invention is a step of mixing the chromium catalyst (A), an organosilicon compound (B) having reducing properties, and an organoaluminum compound (C) in an inert hydrocarbon solvent.

[0045] [Organosilicon compound having reducing properties (B)] A compound having reducing properties refers to a compound that has a high ability to donate electrons. The organosilicon compound (B) preferably has a first ionization potential that can reduce the chromium compound (b). The standard electrode potential E (V) or the electron energy level (eV) is generally used as an index of reducing power. In the case of the standard electrode potential E, the larger the absolute value, the stronger the reducing power. For example, Chem. Rev. 1996, 96, pp. 877-910 classifies reducing agents whose standard electrode potential (VvsFC) is greater than -0.5 (small negative absolute value) as weak reducing agents, those between -0.5 and -1.5 as mild reducing agents, those between -1.5 and -2.5 as strong reducing agents, and those less than -2.5 (large negative absolute value) as very strong reducing agents. When expressed in terms of electronic energy levels, removing an electron from the highest occupied molecular orbital (HOMO) is oxidation, and adding an electron to the lowest unoccupied molecular orbital (LUMO) is reduction, and the work function (eV) is used to represent the energy required to release an electron into a vacuum. In other words, the easier a compound is to remove an electron from its HOMO, the stronger its reducing properties are, and the smaller its work function, the easier it is to act as a reducing agent. Furthermore, since the energy required to release an electron from a molecule is extracted from the electron in the highest-energy molecular orbital, the HOMO energy value corresponds to the ionization potential, and can also be expressed as an index of reducing agents. Representative organosilicon compounds that exhibit reducing properties include the following: Typical reducing agents include compounds with silicon-silicon bonds, and the simplest of these is hexamethyldisilane, which has a peak potential of 1.67 V vs. SCE when measured using a platinum electrode (New J. Chem. 1999, pp. 287-290) and a first ionization potential of 6.1 eV (Sci. Tech. Adv. Mater. 2005, 6, pp. 443-446). Furthermore, as described in Chem. Eur. J. 2019, 25, pp. 913-919 and WO 2014 / 210512, organosilicon compounds with a diazacyclohexadiene structure having a silicon-nitrogen bond and organosilicon compounds with a cyclohexadiene structure having a silicon-carbon bond are known to be effective as reducing agents. For example, the first ionization potential of 1,4-bis(trimethylsilyl)-1,4-dihydropyrazine is 6.16 eV, and the first ionization potential of 3,6-di(trimethylsilyl)-1,4-cyclohexadiene is 7.70 eV (J. Am. Chem. Soc. 1980, 102, pp. 4429-4438). That is, organosilicon compounds with a first ionization potential of 5.5 to 8.0 eV are expected to act as reducing agents, and among these, organosilicon compounds with a first ionization potential of 6.0 to 8.0 eV are preferred.

[0046] The organosilicon compound (B) used in the present invention includes organosilicon compounds having a silicon-silicon bond, organosilicon compounds having a diazacyclohexadiene structure and a silicon-nitrogen bond, and organosilicon compounds having a cyclohexadiene structure and a silicon-carbon bond, all of which have a first ionization potential of 5.5 to 8.0 eV.

[0047] The organosilicon compound (B) used in the present invention may be an organosilicon compound represented by the following general formula (I), an organosilicon compound represented by the following general formula (IIA), an organosilicon compound represented by the following general formula (IIB), an organosilicon compound represented by the following general formula (IIIA), or an organosilicon compound represented by the following general formula (IIIB).

[0048] [ka] [In formula (I), R 1 , R 2 , R 3 , R 4 , R 5 and R 6 are each independently a hydrogen atom, a halogen atom, a hydrocarbon group having 1 to 30 carbon atoms, or a substituent containing at least one heteroatom selected from the group consisting of an oxygen atom, a sulfur atom, a nitrogen atom, a phosphorus atom, and a silicon atom, or R 1 , R 2 , R 3 , R 4 , R 5 and R 6 may be bonded to each other to form a cyclic structure, and the hydrocarbon group may have a substituent containing a halogen atom or at least one heteroatom selected from the group consisting of an oxygen atom, a sulfur atom, a nitrogen atom, a phosphorus atom, and a silicon atom.

[0049] [ka] [In formula (IIA) and formula (IIB), R11 , R 11’ , R 11” , R 12 , R 13 , R 14 , and R 15 are each independently a hydrogen atom, a hydrocarbon group having 1 to 14 carbon atoms, or an aromatic heterocyclic group having 4 to 14 carbon atoms.

[0050] [ka] [In formula (IIIA) and formula (IIIB), R 11 , R 11’ , R 11” , R 12 , R 13 , R 14 , R 15 , R 16 and R 17 are each independently a hydrogen atom, a hydrocarbon group having 1 to 14 carbon atoms, or an aromatic heterocyclic group having 4 to 14 carbon atoms.

[0051] In formula (I), R 1 , R 2 , R 3 , R 4 , R 5 and R 6 Examples of the halogen atom represented by the formula (I) include a chloro group, a bromo group, an iodo group, and a fluoro group.

[0052] In formula (I), R 1 , R 2 , R 3 , R 4 , R 5 and R 6Examples of the hydrocarbon group having 1 to 30 carbon atoms represented by the formula (I) include alkyl groups, cycloalkyl groups, alkenyl groups, aryl groups, arylalkyl groups, and combinations thereof. Of these, preferred hydrocarbon groups having 1 to 30 carbon atoms are alkyl groups, cycloalkyl groups, aryl groups, and arylalkyl groups, more preferably alkyl groups and aryl groups, and even more preferably alkyl groups. Examples of alkyl groups include methyl, ethyl, n-propyl, isopropyl, n-butyl, sec-butyl, tert-butyl, n-pentyl, neopentyl, isopentyl, n-hexyl, n-heptyl, n-octyl, n-decyl, n-nonyl, n-decyl, n-dodecyl, n-tridecyl, n-tetradecyl, n-pentadecyl, n-hexadecyl, n-heptadecyl, n-octadecyl, n-nonadecyl, n-eicosyl, n-pentacosyl, and n-triacontyl. Alkyl groups having 1 to 10 carbon atoms are preferred, and alkyl groups having 1 to 6 carbon atoms are more preferred. Examples of cycloalkyl groups include cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, norbornyl, and adamantyl. Examples of alkenyl groups include vinyl, propenyl, and cyclohexenyl groups. Examples of aryl groups include alkyl groups, which may be substituted, such as phenyl, tolyl, xylyl, trimethylphenyl, tetramethylphenyl, pentamethylphenyl, ethylphenyl, n-propylphenyl, isopropylphenyl, n-butylphenyl, sec-butylphenyl, tert-butylphenyl, isobutylphenyl, n-pentylphenyl, neopentylphenyl, n-hexylphenyl, n-octylphenyl, n-decylphenyl, n-dodecylphenyl, n-tetradecylphenyl, naphthyl, biphenyl, anthracenyl, and phenanthryl groups. Aryl groups having 6 to 20 carbon atoms are preferred, and aryl groups having 6 to 15 carbon atoms are even more preferred. Phenyl groups are even more preferred. Examples of arylalkyl groups include benzyl, phenylethyl, and phenylpropyl groups.

[0053] In formula (I), R 1 , R 2 , R 3 , R 4 , R 5 and R 6 Examples of the substituent containing at least one heteroatom selected from the group consisting of an oxygen atom, a sulfur atom, a nitrogen atom, a phosphorus atom, and a silicon atom include an alkoxy group, an acyl group, an alkylthio group, an amino group, a phosphino group, a silyl group, and a heterocyclic group. Examples of alkoxy groups include methoxy, ethoxy, propoxy, and butoxy groups. Preferred are methoxy, ethoxy, and butoxy groups. Examples of acyl groups include acetyl, oxopropyl, and benzoyl groups. Examples of alkylthio groups include methylthio, ethylthio, propylthio, butylthio, and phenylthio groups. Preferred is the methylthio group. Examples of amino groups include amino (-NH), methylamino, dimethylamino, diethylamino, ethylmethylamino, and dipropylamino groups. Preferred are amino (-NH) and dimethylamino groups. Examples of phosphino groups include dimethylphosphino, diethylphosphino, diisopropylphosphino, di-tert-butylphosphino, and diphenylphosphino groups. Preferred are di-tert-butylphosphino and diphenylphosphino groups. Examples of the silyl group include a dimethylsilyl group, a trimethylsilyl group, a triethylsilyl group, a triisopropyl group, and a tert-butyldimethylsilyl group. Dimethylsilyl and trimethylsilyl groups are preferred. In the heteroatom-containing substituent, the hydrocarbon group bonded to the heteroatom may be a C1-C6 alkyl group or a phenyl group. The heterocyclic group may be a heterocyclic group constituting a 5- or 6-membered ring which may have at least one substituent, and examples thereof include nitrogen-containing heterocyclic groups such as a pyrrole group, a pyrazole group, and a pyridine group, oxygen-containing heterocyclic groups such as a furan group, sulfur-containing heterocyclic groups such as a thiophene group, and groups in which these heterocyclic groups are substituted with a substituent such as an alkyl group or an alkoxy group having 1 to 30 carbon atoms.

[0054] In formula (I), R 1 , R 2 , R 3 , R 4 , R 5 and R 6 The structure in which the ring structures are formed by bonding with each other is R 1 , R 2 , R 3 , R 4 , R 5 and R 6 may be a structure in which hydrocarbon groups having 1 to 30 carbon atoms, represented by the formula (I), are crosslinked at any position to form a cyclic structure, a structure in which adjacent groups are crosslinked to form a cyclic structure, or a cyclic structure may be formed together with Si-Si in formula (I). Examples of such cyclic structures include silacyclopentane, silacyclohexane, silaindene, silafluorene, disilacyclobutane, disilacyclopentane, disilacyclohexane, disilacycloheptane, disilaindene, and disilaacenaphthalene.

[0055] In formula (I), R 1 , R 2 , R 3 , R 4 , R 5 and R 6 The hydrocarbon group having 1 to 30 carbon atoms represented by the formula (I) may have a substituent containing a halogen atom or at least one heteroatom selected from the group consisting of an oxygen atom, a sulfur atom, a nitrogen atom, a phosphorus atom, and a silicon atom. The substituent containing at least one heteroatom selected from the group consisting of an oxygen atom, a sulfur atom, a nitrogen atom, a phosphorus atom, and a silicon atom may be the same as those described above, and may further be a thio group (-SH). Preferred examples of the substituent on the hydrocarbon group having 1 to 30 carbon atoms include an alkoxy group, an acyl group, a thio group, an amino group, a phosphino group, a chloro group, a bromo group, an iodo group, a fluoro group, a trifluoromethyl group, a silyl group, etc. Among these, an alkoxy group, an amino group, a phosphino group, a chloro group, a fluoro group, a trifluoromethyl group, and a silyl group are preferred, an alkoxy group, a chloro group, a fluoro group, a trifluoromethyl group, and a silyl group are more preferred, and an alkoxy group, a chloro group, a fluoro group, a trifluoromethyl group, and a silyl group are even more preferred.

[0056] The organosilicon compound represented by general formula (I) according to the present invention is preferably R 1 , R 2 , R 3 , R 4 , R 5 and R 6 are each independently a hydrogen atom, a halogen atom, a hydrocarbon group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, a dimethylsilyl group, or a trimethylsilyl group, and R 2 , R 3 , R 4 , R 5 and R 6 may be bonded to each other to form a 5- or 6-membered ring structure, and R 1 , R 2 , R 3 , R 4 , R 5 and R 6 and R 1 , R 2 , R 3 , R 4 , R 5 and R 6 are each independently a hydrocarbon group having 1 to 6 carbon atoms. The hydrocarbon group having 1 to 6 carbon atoms may be an alkyl group or phenyl group having 1 to 6 carbon atoms, an alkyl group or phenyl group having 1 to 4 carbon atoms, or an alkyl group or phenyl group having 1 to 2 carbon atoms.

[0057] Specific examples of the organosilicon compound represented by general formula (I) according to the present invention include, preferably, hexamethyldisilane, hexaethyldisilane, hexaphenyldisilane, 1,2-diethyl-1,1,2,2-tetramethyldisilane, 1,1,2,2-tetraethyl-1,2-dimethyldisilane, 1-methyl-1,1,2,2,2-pentaphenyldisilane, 1,1-dimethyl-1,2,2,2-tetraphenyldisilane, 1,2-dimethyl-1,1,2,2-tetraphenyldisilane, 1,1,1-trimethyl-2,2,2-triphenyldisilane, 1,1,2 -Trimethyl-1,2,2-triphenyldisilane, 1,1,1,2-tetramethyl-2,2-diphenyldisilane, 1,1,2,2-tetramethyl-1,2-diphenyldisilane, 1,1,1,2,2-pentamethyl-2-phenyldisilane, 1-chloro-1,1,2,2,2-pentamethyldisilane, 1,2-dichloro-1,1,2,2-tetramethyldisilane, 1,2-dimethoxy-1,1,2,2-tetramethyldisilane, 1,2-diethoxy-1,1,2,2-tetramethyldisilane, 1,2-dibutoxy-tetramethyldisilane, 1,1,2 ,2-tetramethyl-1,2-disilacyclopentane, 1,1,2,2-tetramethyl-1,2-disilacyclohexane, tris(trimethylsilyl)silane, tetrakis(dimethylsilyl)silane, and more preferably hexamethyldisilane, hexaethyldisilane, hexaphenyldisilane, 1,2-diethyl-1,1,2,2-tetramethyldisilane, 1,1,2,2-tetraethyl-1,2-dimethyldisilane, 1-methyl-1,1,2,2,2-pentaphenyldisilane, 1,1-dimethyl-1,2,2,2-tetraphenyldisilane, 1,2 -dimethyl-1,1,2,2-tetraphenyldisilane, 1,1,1-trimethyl-2,2,2-triphenyldisilane, 1,1,2-trimethyl-1,2,2-triphenyldisilane, 1,1,1,2-tetramethyl-2,2-diphenyldisilane, 1,1,2,2-tetramethyl-1,2-diphenyldisilane, 1,1,1,2,2-pentamethyl-2-phenyldisilane, and more preferably hexamethyldisilane, hexaethyldisilane, hexaphenyldisilane, 1,2-diethyl-1,1,2,2-tetramethyldisilane, 1,1,2,2-tetraethyl-1,2-dimethyldisilane, 1,2-dimethyl-1,1,2,2-tetraphenyldisilane, and 1,1,2,2-tetramethyl-1,2-diphenyldisilane. Most preferred are hexamethyldisilane, hexaethyldisilane, and hexaphenyldisilane.

[0058] In formula (IIA) and formula (IIB), R 11 , R 11’ , R 11” , R 12 , R 13 , R 14 , and R 15 are each independently a hydrogen atom, a hydrocarbon group having 1 to 14 carbon atoms, or an aromatic heterocyclic group having 4 to 14 carbon atoms. Examples of the hydrocarbon group having 1 to 14 carbon atoms include alkyl groups, cycloalkyl groups, alkenyl groups, aryl groups, and arylalkyl groups, as well as combinations thereof. In formula (IIA) and formula (IIB), R 11 , R 11’ , R 11” , R 12 , R 13 , R 14 , and R 15 may each independently be a hydrogen atom, an alkyl group having 1 to 10 carbon atoms, an aryl group having 6 to 14 carbon atoms, or an aromatic heterocyclic group having 4 to 14 carbon atoms. R 11 , R 11’ , R 11” , R 12 , R 13 , R 14 , and R 15 In the formula (I), examples of the alkyl group having 1 to 10 carbon atoms include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, a sec-butyl group, a tert-butyl group, an n-pentyl group, a neopentyl group, an isopentyl group, an n-hexyl group, an n-heptyl group, an n-octyl group, an n-decyl group, and an n-nonyl group, and preferably an alkyl group having 1 to 6 carbon atoms, and more preferably a methyl group. R 11 , R 11’ , R 11” , R 12 , R13 , R 14 , and R 15 In the formula, the aryl group having 6 to 14 carbon atoms may be substituted with a hydrocarbon group such as an alkyl group, and examples thereof include a phenyl group, a 2-methylphenyl group, a 3-methylphenyl group, a 4-methylphenyl group, a 3,5-dimethylphenyl group, a 2,4,6-trimethylphenyl group, a 4-t-butylphenyl group, a naphthyl group, a biphenyl group, a 1-phenylethyl group, a 2-phenylethyl group, a diphenylmethyl group, a styryl group, a cinnamyl group, an anthryl group, and a phenanthryl group. R 11 , R 11’ , R 11” , R 12 , R 13 , R 14 , and R 15 In the formula (I), the aromatic heterocyclic group having 4 to 14 carbon atoms may be substituted with a hydrocarbon group such as an alkyl group, and examples thereof include a furan group, a pyrrole group, a thiophene group, an oxazole group, a thiazole group, an imidazole group, a pyrazole group, a pyran group, a pyridine group, a pyridazine group, a pyrimidine group, and a pyrazine group.

[0059] In formula (IIA) and formula (IIB), R 11 , R 11’ , R 11” are each independently an alkyl group preferably having 1 to 10 carbon atoms, and R 12 , R 13 , R 14 , and R 15 are each independently preferably a hydrogen atom or an alkyl group having 1 to 10 carbon atoms.

[0060] Specific examples of the organosilicon compound represented by general formula (IIA) according to the present invention include 1,4-bis(trimethylsilyl)-1,4-dihydropyrazine, 2-methyl-1,4-bis(trimethylsilyl)-1,4-dihydropyrazine, 2,3-dimethyl-1,4-bis(trimethylsilyl)-1,4-dihydropyrazine, 2,5-dimethyl-1,4-bis(trimethylsilyl)-1,4-dihydropyrazine, 2,6-dimethyl-1,4-bis(trimethylsilyl)-1,4-dihydropyrazine, 2,3,5,6-tetramethyl-1,4-bis(trimethylsilyl)-1,4-dihydropyrazine and the like.

[0061] Specific examples of the organosilicon compound represented by general formula (IIB) according to the present invention include 1,2-bis(trimethylsilyl)-1,2-dihydropyrazine, 3-methyl-1,2-bis(trimethylsilyl)-1,2-dihydropyrazine, 4-methyl-1,2-bis(trimethylsilyl)-1,2-dihydropyrazine, 5-methyl-1,2-bis(trimethylsilyl)-1,2-dihydropyrazine, 6-methyl-1,2-bis(trimethylsilyl)-1,2-dihydropyrazine, 3,4-dimethyl-1,2-bis(trimethylsilyl)-1,2-dihydropyrazine, 3,5-dimethyl-1,2-bis(trimethylsilyl)-1,2-dihydropyrazine, 3,6-dimethyl-1,2-bis(trimethylsilyl)-1,2-dihydropyrazine, 4,5-dimethyl-1,2-bis(trimethylsilyl)-1,2-dihydropyrazine, 4,6-dimethyl-1,2-bis(trimethylsilyl)-1,2-dihydropyrazine, 5,6-dimethyl-1,2-bis(trimethylsilyl)-1,2-dihydropyrazine, 3,4,5,6-tetramethyl-1,2-bis(trimethylsilyl)-1,2-dihydropyrazine and the like.

[0062] In formula (IIIA) and formula (IIIB), R 11 , R 11’ , R 11” , R 12 , R 13 , R 14 , R 15 , R 16 and R 17are each independently a hydrogen atom, a hydrocarbon group having 1 to 14 carbon atoms, or an aromatic heterocyclic group having 4 to 14 carbon atoms. In formula (IIIA) and formula (IIIB), the hydrocarbon group having 1 to 14 carbon atoms or the aromatic heterocyclic group having 4 to 14 carbon atoms may be the same as those explained above in formula (IIA) and formula (IIB).

[0063] In formula (IIIA) and formula (IIIB), R 11 , R 11’ , R 11” are each independently an alkyl group preferably having 1 to 10 carbon atoms, and R 12 , R 13 , R 14 , and R 15 are each independently preferably a hydrogen atom or an alkyl group having 1 to 10 carbon atoms, and R 16 and R 17 is preferably a hydrogen atom.

[0064] Specific examples of the organosilicon compound represented by general formula (IIIA) according to the present invention include 3,6-di(trimethylsilyl)-1,4-cyclohexadiene, 1-methyl-3,6-di(trimethylsilyl)-1,4-cyclohexadiene, 1,2-dimethyl-3,6-di(trimethylsilyl)-1,4-cyclohexadiene, 1,4-dimethyl-3,6-di(trimethylsilyl)-1,4-cyclohexadiene, 1,5-dimethyl-3,6-di(trimethylsilyl)-1,4-cyclohexadiene, Examples include 1,2,4,5-tetramethyl-3,6-di(trimethylsilyl)-1,4-cyclohexadiene.

[0065] Specific examples of the organosilicon compound represented by general formula (IIIB) according to the present invention include 5,6-di(trimethylsilyl)-1,3-cyclohexadiene, 1-methyl-5,6-bis(trimethylsilyl)-1,3-cyclohexadiene, 2-methyl-5,6-bis(trimethylsilyl)-1,3-cyclohexadiene, 3-methyl-5,6-bis(trimethylsilyl)-1,3-cyclohexadiene, 4-methyl-5,6-bis(trimethylsilyl)-1,3-cyclohexadiene, Examples include 1,2-dimethyl-5,6-bis(trimethylsilyl)-1,3-cyclohexadiene, 1,3-dimethyl-5,6-bis(trimethylsilyl)-1,3-cyclohexadiene, 1,4-dimethyl-5,6-bis(trimethylsilyl)-1,3-cyclohexadiene, 1,5-dimethyl-5,6-bis(trimethylsilyl)-1,3-cyclohexadiene, and 1,2,4,5-tetramethyl-5,6-bis(trimethylsilyl)-1,3-cyclohexadiene.

[0066] [Organoaluminum compounds (C)] The organoaluminum compound (C) is a compound having a carbon-aluminum (C-Al) bond. As the organoaluminum compound (C) used in the present invention, at least one compound can be appropriately selected from conventionally known organoaluminum compounds and organoaluminum oxy-compounds.

[0067] The organoaluminum compound (C) used in the present invention may be at least one selected from the group consisting of aluminum compounds represented by the following general formula (1), aluminum oxy compounds represented by the following general formula (2-1), and aluminum oxy compounds represented by the following general formula (2-2). General formula (1): AlR 21 3 (In formula (1), R 21 are each independently an alkyl group, an alkoxy group, an aryloxy group, or a siloxy group, and may be the same or different from one another, and the aryloxy group may be substituted with an alkyl group, a halogen atom, an alkoxy group, or a nitrile group.

[0068] [ka] (In formulas (2-1) and (2-2), R 22 are each independently an alkyl group, an alkoxy group, an aryloxy group, or a siloxy group, and may be the same or different from one another, and the aryloxy group may be substituted with an alkyl group, a halogen atom, an alkoxy group, or a nitrile group. n represents an integer of 0 or more, and m represents an integer of 2 or more.

[0069] The organoaluminum compound (C) used in the present invention may be one or more of them, and two or more of the aluminum compounds represented by the general formula (1) may be mixed and used, two or more of the aluminum oxy compounds represented by the general formula (2-1) may be mixed and used, two or more of the aluminum oxy compounds represented by the general formula (2-2) may be mixed and used, one or more of the aluminum compounds represented by the general formula (1) may be mixed with one or more of the aluminum oxy compounds represented by the general formula (2-1) may be mixed and used, One or more aluminum compounds represented by general formula (1) may be mixed with one or more aluminum oxy compounds represented by general formula (2-2) and used; one or more aluminum compounds represented by general formula (2-1) may be mixed with one or more aluminum oxy compounds represented by general formula (2-2) and used; or one or more aluminum compounds represented by general formula (1), one or more aluminum oxy compounds represented by general formula (2-1) and one or more aluminum oxy compounds represented by general formula (2-2) may be mixed with one or more aluminum compounds represented by general formula (1).

[0070] R in general formula (1) 21 and R in general formulas (2-1) and (2-2) 22In the general formulas (1), (2-1), and (2-2), the alkyl group may be a straight-chain, branched, or cyclic alkyl group. In the general formulas (1), (2-1), and (2-2), the alkyl group may be an alkyl group having 1 to 18 carbon atoms, an alkyl group having 1 to 12 carbon atoms, an alkyl group having 1 to 8 carbon atoms, or an alkyl group having 1 to 6 carbon atoms. Examples of the alkyl group include a methyl group, an ethyl group, an n-propyl group, an i-propyl group, an n-butyl group, an i-butyl group, a sec-butyl group, a tert-butyl group, an n-pentyl group, an n-hexyl group, an n-octyl group, an n-decyl group, an n-dodecyl group, and a cyclohexyl group, and may be at least one of a methyl group, an ethyl group, an n-butyl group, an i-butyl group, an n-hexyl group, and an n-octyl group.

[0071] R in general formula (1) 21 and R in general formulas (2-1) and (2-2) 22 In the general formulae (1), (2-1) and (2-2), the alkoxy group may be a linear, branched or cyclic alkoxy group. In the general formulae (1), (2-1) and (2-2), the alkoxy group may be an alkoxy group having 1 to 18 carbon atoms, an alkoxy group having 1 to 12 carbon atoms, an alkoxy group having 1 to 8 carbon atoms or an alkoxy group having 1 to 6 carbon atoms. Examples of the alkoxy group include a methoxy group, an ethoxy group, an n-propoxy group, an i-propoxy group, an n-butoxy group, an i-butoxy group, a sec-butoxy group, a tert-butoxy group, an n-pentyloxy group, an n-hexyloxy group, an n-octyloxy group, an n-decyloxy group, an n-dodecyloxy group, and a cyclohexyloxy group, and may be at least one of a methoxy group, an ethoxy group, an n-propoxy group, an i-propoxy group, an n-butoxy group, an i-butoxy group, a sec-butoxy group, a tert-butoxy group, an n-pentyloxy group, an n-hexyloxy group, and an n-octyloxy group.

[0072] R in general formula (1) 21 and R in general formulas (2-1) and (2-2) 22In the above formula, the aryloxy group may be an aryloxy group having 6 to 18 carbon atoms, or may be an aryloxy group having 6 to 12 carbon atoms. Examples of the aryloxy group include a phenoxy group and a naphthyloxy group. The aryloxy group may be substituted with an alkyl group, a halogen atom, an alkoxy group, or a nitrile group. Examples of the alkyl group that may be substituted with the aryloxy group include the same as the alkyl group described above. Examples of the alkoxy group that may be substituted with the aryloxy group include the same as the alkoxy group described above. Examples of the halogen atom which may be substituted on the aryloxy group include a fluoro group, a chloro group, a bromo group, and an iodo group. The aryloxy group may be unsubstituted or substituted with at least one of a methyl group, a fluoro group, a chloro group, a methoxy group, and a nitrile group, and may be unsubstituted or substituted with at least one of a methyl group, a fluoro group, and a methoxy group.

[0073] R in general formula (1) 21 and R in general formulas (2-1) and (2-2) 22 In the formula, the siloxy group is represented by -OSi(RR'R") (wherein R, R', and R" are each independently a hydrogen atom or an alkyl group). Examples of the alkyl group in R, R', and R" include the same as those described above for the alkyl group. At least one of R, R', and R" may be an alkyl group, and at least two of R, R', and R" may be alkyl groups. Examples of the siloxy group include trimethylsiloxy group, triethylsiloxy group, tri-i-propylsiloxy group, dimethylhydrosiloxy group, dimethylethylsiloxy group, ethylhydromethylsiloxy group, n-butyldimethylsiloxy group, n-butylhydromethylsiloxy group, i-butyldimethylsiloxy group, i-butylhydromethylsiloxy group, dimethyl-n-hexylsiloxy group, n-hexylhydromethylsiloxy group, dimethyl-n-octylsiloxy group, and hydromethyl-n-octylsiloxy group, and may be at least one of trimethylsiloxy group, triethylsiloxy group, dimethylhydrosiloxy group, dimethylethylsiloxy group, and ethylhydromethylsiloxy group.

[0074] In the aluminum compound represented by the general formula (1), R 21 Examples of aluminum in which the three groups are each independently an alkyl group include trimethylaluminum, triethylaluminum, tri-n-propylaluminum, triisopropylaluminum, tri-n-butylaluminum, triisobutylaluminum, tri-s-butylaluminum, tri-t-butylaluminum, tri-n-hexylaluminum, tricyclohexylaluminum, tri-n-octylaluminum, and tri-n-decylaluminum.

[0075] In the aluminum compound represented by the general formula (1), R 21 At least one of R is an alkyl group, and 21 In the case where at least one of R is an alkoxy group, an alkylaluminum alkoxide can be mentioned. 21 are alkyl groups, and R 21 Dialkylaluminum alkoxide, where one of the groups is an alkoxy group, R 21 One of the groups is an alkyl group, and R 21 Examples of the aluminum alkoxide include alkylaluminum dialkoxides in which two of the groups are alkoxy groups, but they may also be dialkylaluminum alkoxides. Examples of dialkylaluminum alkoxides include dimethylaluminum methoxide, dimethylaluminum ethoxide, dimethylaluminum n-propoxide, dimethylaluminum n-butoxide, diethylaluminum methoxide, diethylaluminum ethoxide, diethylaluminum n-propoxide, diethylaluminum n-butoxide, di-n-propylaluminum methoxide, di-n-propylaluminum ethoxide, di-n-propylaluminum n-propoxide, di-n-propylaluminum n-butoxide, di-i-propylaluminum methoxide, di-i-propylaluminum ethoxide, di-i-propylaluminum n-propoxide, di-i-propylaluminum n-butoxide, di-n-butylaluminum methoxide, and di-n-butylaluminum methoxide. di-n-butylaluminum ethoxide, di-n-butylaluminum n-propoxide, di-n-butylaluminum n-butoxide, di-i-butylaluminum methoxide, di-i-butylaluminum ethoxide, di-i-butylaluminum n-propoxide, di-i-butylaluminum n-butoxide, dimethylaluminum (cyclopentyl) methoxide, diethylaluminum (cyclopentyl) methoxide, di-n-butylaluminum (cyclopentyl) methoxide, di-i-butylaluminum (cyclopentyl) methoxide, dimethylaluminum (cyclohexyl) methoxide, diethylaluminum (cyclohexyl) methoxide, di-n-butylaluminum (cyclohexyl) methoxide, di-i-butylaluminum (cyclohexyl) methoxide, dimethylaluminum 2-Methyl-2-propoxide, dimethylaluminum 2-Methyl-2-butoxide, dimethylaluminum 3-Methyl-3-pentoxide, dimethylaluminum 3-Ethyl-3-pentoxide, diethylaluminum 2-Methyl-2-propoxide, diethylaluminum 2-Methyl-2-butoxide, diethylaluminum 3-Methyl-3-pentoxide, diethylaluminum 3-Ethyl-3-pentoxide, di-n-butylaluminum 2-Methyl-2-propoxide, di-n-butylaluminum 2-Methyl-2-butoxide, di-n-butylaluminum 3-Methyl-3-pentoxide, di-n-butylaluminum3-ethyl-3-pentoxide, di-i-butylaluminum 2-methyl-2-propoxide, di-i-butylaluminum 2-methyl-2-butoxide, di-i-butylaluminum 3-methyl-3-pentoxide, di-i-butylaluminum 3-ethyl-3-pentoxide, di-n-hexylaluminum 2-methyl-2-propoxide, di-n-hexylaluminum 2-methyl-2-butoxide, di-n-hexylaluminum 3-methyl-3-pentoxide, di-n-hexylaluminum 3-ethyl-3-pentoxide, di-n-octylaluminum 2-methyl-2-propoxide, di-n-octylaluminum 2-methyl-2-butoxide, di-n-octylaluminum 3-methyl-3-pentoxide, di-n-octylaluminum 3-ethyl-3-pentoxide, and the like.

[0076] In the aluminum compound represented by the general formula (1), R 21 At least one of R is an alkyl group, and 21 In the case where at least one of R is an aryloxy group, for example, R 21 are alkyl groups, and R 21 In the above, one of the alkyl groups is an aryloxy group, and examples thereof include dialkylaluminum aryloxides, such as dialkylaluminum phenoxides. Examples of dialkylaluminum phenoxides include dimethylaluminum phenoxide, dimethylaluminum 4-methylphenoxide, dimethylaluminum 2,6-dimethylphenoxide, dimethylaluminum 2,4,6-trimethylphenoxide, dimethylaluminum 2-fluorophenoxide, dimethylaluminum 3-fluorophenoxide, dimethylaluminum 4-fluorophenoxide, dimethylaluminum 2-methoxyphenoxide, dimethylaluminum 4-methoxyphenoxide, diethylaluminum phenoxide, diethylaluminum 4-methylphenoxide, diethylaluminum 2,6-dimethylphenoxide, diethylaluminum 2,4,6-trimethylphenoxide, diethylaluminum 2-fluorophenoxide, diethylaluminum 3-fluorophenoxide, diethylaluminum 4-fluorophenoxide, diethylaluminum 2-methoxyphenoxide, diethylaluminum 4-methoxyphenoxide, di-n-butylaluminum phenoxide, and di-n-butylaluminum. 4-Methylphenoxide, di-n-butylaluminum 2,6-dimethylphenoxide, di-n-butylaluminum 2,4,6-trimethylphenoxide, di-n-butylaluminum 2-fluorophenoxide, di-n-butylaluminum 3-fluorophenoxide, di-n-butylaluminum 4-fluorophenoxide, di-n-butylaluminum 2-methoxyphenoxide, di-n-butylaluminum 4-methoxyphenoxide, di-i-butylaluminum Phenoxide, di-i-butylaluminum 4-methylphenoxide, di-i-butylaluminum 2,6-dimethylphenoxide, di-i-butylaluminum 2,4,6-trimethylphenoxide, di-i-butylaluminum 2-fluorophenoxide, di-i-butylaluminum 3-fluorophenoxide, di-i-butylaluminum 4-fluorophenoxide, di-i-butylaluminum 2-methoxyphenoxide, di-i-butylaluminum 4-Methoxyphenoxide, di-n-hexylaluminum Phenoxide, di-n-hexylaluminum 4-Methylphenoxide, di-n-hexylaluminum 2,6-Dimethylphenoxide, Di-n-hexylaluminum 2,4,6-Trimethylphenoxide, Di-n-hexylaluminum 2-Fluorophenoxide, Di-n-hexylaluminum 3-Fluorophenoxide, Di-n-hexylaluminum 4-Fluorophenoxide, Di-n-hexylaluminum 2-Methoxyphenoxide, Di-n-hexylaluminum 4-Methoxyphenoxide, Di-n-octylaluminum Phenoxide, Di-n-octylaluminum 4-Methylphenoxide, Di-n-octylaluminum 2,6-Dimethylphenoxide, Di-n-octylaluminum 2,4,6-Trimethylphenoxide, Di-n-octylaluminum 2-Fluorophenoxide, Di-n-octylaluminum 3-Fluorophenoxide, Di-n-octylaluminum 4-Fluorophenoxide, Di-n-octylaluminum Examples include di-n-octylaluminum 2-methoxyphenoxide, di-n-octylaluminum 4-methoxyphenoxide, etc.

[0077] In the aluminum compound represented by the general formula (1), R 21 At least one of R is an alkyl group, and 21 In the case where at least one of the groups is a siloxy group, for example, R 21 are alkyl groups, and R 21 One of the groups is dialkylaluminum siloxide, which has a siloxy group. Examples of dialkylaluminum siloxides include dimethylaluminum trimethylsiloxide, dimethylaluminum triethylsiloxide, dimethylaluminum tri-i-propylsiloxide, diethylaluminum trimethylsiloxide, diethylaluminum triethylsiloxide, diethylaluminum tri-i-propylsiloxide, di-n-butylaluminum trimethylsiloxide, di-n-butylaluminum triethylsiloxide, di-n-butylaluminum tri-i-propylsiloxide, di-n-butylaluminum trimethylsiloxide, di-n-butylaluminum triethylsiloxide, di-n-butylaluminum tri-i-propylsiloxide, di-n-hexylaluminum trimethylsiloxide, di-n-hexylaluminum triethylsiloxide, di-n-hexylaluminum tri-i-propylsiloxide, di-n-octylaluminum trimethylsiloxide, di-n-octylaluminum triethylsiloxide, and di-n-octylaluminum. Examples of such siloxides include tri-i-propylsiloxide, dimethylaluminum dimethylhydrosiloxide, diethylaluminum dimethylethylsiloxide, diethylaluminum ethylhydromethylsiloxide, di-n-butylaluminum n-butyldimethylsiloxide, di-n-butylaluminum n-butylhydromethylsiloxide, di-i-butylaluminum i-butyldimethylsiloxide, di-i-butylaluminum i-butylhydromethylsiloxide, di-n-hexylaluminum dimethyl-n-hexylsiloxide, di-n-hexylaluminum n-hexylhydromethylsiloxide, di-n-octylaluminum dimethyl-n-octylsiloxide, and di-n-octylaluminum hydromethyl-n-octylsiloxide.

[0078] In the aluminum compound represented by the general formula (1), R 21 One of the groups is an alkyl group, and R 21 is an alkoxy group, and R 21 In the case where one of the groups is a siloxy group, alkylaluminum (alkoxide) (siloxide) can be mentioned. Examples of alkylaluminum (alkoxide) (siloxide) include methylaluminum (methoxide) (trimethylsiloxide), methylaluminum (methoxide) (triethylsiloxide), methylaluminum (methoxide) (ethyldimethylsiloxide), methylaluminum (methoxide) (i-butyldimethylsiloxide), methylaluminum (ethoxide) (trimethylsiloxide), methylaluminum (ethoxide) (triethylsiloxide), methylaluminum (ethoxide) (ethyldimethylsiloxide), methyl Aluminum (ethoxide) (i-butyldimethylsiloxide), methylaluminum (i-propoxide) (trimethylsiloxide), methylaluminum (i-propoxide) (triethylsiloxide), methylaluminum (i-propoxide) (ethyldimethylsiloxide), methylaluminum (i-propoxide) (i-butyldimethylsiloxide), methylaluminum (n-butoxide) (trimethylsiloxide), methylaluminum (n-butoxide) (triethylsiloxide), methylaluminum (n-butoxide) (ethyldimethylsiloxide) Methylsiloxide), methylaluminum (n-butoxide) (i-butyldimethylsiloxide), methylaluminum (i-butoxide) (trimethylsiloxide), methylaluminum (i-butoxide) (triethylsiloxide), methylaluminum (i-butoxide) (ethyldimethylsiloxide), methylaluminum (i-butoxide) (i-butyldimethylsiloxide), methylaluminum (tert-butoxide) (trimethylsiloxide), methylaluminum (tert-butoxide) (triethylsiloxide), methylaluminum aluminum (tert-butoxide) (ethyldimethylsiloxide), methylaluminum (tert-butoxide) (i-butyldimethylsiloxide), ethylaluminum (methoxide) (trimethylsiloxide), ethylaluminum (methoxide) (triethylsiloxide), ethylaluminum (methoxide) (ethyldimethylsiloxide), ethylaluminum (methoxide) (i-butyldimethylsiloxide), ethylaluminum (ethoxide) (trimethylsiloxide), ethylaluminum (ethoxide) (triethylsiloxide),Ethyl aluminum ethoxide (ethyl dimethyl siloxide), ethyl aluminum ethoxide (i-butyl dimethyl siloxide), ethyl aluminum i-propoxide (trimethyl siloxide), ethyl aluminum i-propoxide (triethyl siloxide), ethyl aluminum i-propoxide (ethyl dimethyl siloxide), ethyl aluminum i-propoxide (i-butyl dimethyl siloxide), ethyl aluminum n-butoxide (trimethyl siloxide), ethyl aluminum n-butoxide (triethyl siloxide), ethyl aluminum n-butoxide (ethyl dimethyl siloxide), ethyl aluminum aluminum (n-butoxide) (i-butyldimethylsiloxide), ethylaluminum (i-butoxide) (trimethylsiloxide), ethylaluminum (i-butoxide) (triethylsiloxide), ethylaluminum (i-butoxide) (ethyldimethylsiloxide), ethylaluminum (i-butoxide) (i-butyldimethylsiloxide), ethylaluminum (tert-butoxide) (trimethylsiloxide), ethylaluminum (tert-butoxide) (triethylsiloxide), ethylaluminum (tert-butoxide) (ethyldimethylsiloxide), ethylaluminum (tert-butoxide) (i-butyldimethylsiloxide),

[0079] n-Butylaluminum (methoxide) (trimethylsiloxide), n-butylaluminum (methoxide) (triethylsiloxide), n-butylaluminum (methoxide) (ethyldimethylsiloxide), n-butylaluminum (methoxide) (i-butyldimethylsiloxide), n-butylaluminum (ethoxide) (trimethylsiloxide), n-butylaluminum (ethoxide) (triethylsiloxide), n-butylaluminum (ethoxide) (ethyldimethylsiloxide), n-butylaluminum (ethoxide) (i-butyldimethylsiloxide) ethyldimethylsiloxide), n-butylaluminum (i-propoxide) (trimethylsiloxide), n-butylaluminum (i-propoxide) (triethylsiloxide), n-butylaluminum (i-propoxide) (ethyldimethylsiloxide), n-butylaluminum (i-propoxide) (i-butyldimethylsiloxide), n-butylaluminum (n-butoxide) (trimethylsiloxide), n-butylaluminum (n-butoxide) (triethylsiloxide), n-butylaluminum (n-butoxide) (ethyldimethylsiloxide) tylsiloxide), n-butylaluminum (n-butoxide) (i-butyldimethylsiloxide), n-butylaluminum (i-butoxide) (trimethylsiloxide), n-butylaluminum (i-butoxide) (triethylsiloxide), n-butylaluminum (i-butoxide) (ethyldimethylsiloxide), n-butylaluminum (i-butoxide) (i-butyldimethylsiloxide), n-butylaluminum (tert-butoxide) (trimethylsiloxide), n-butylaluminum (tert-butoxide) (triethylsiloxide) ethylsiloxide), n-butylaluminum (tert-butoxide) (ethyldimethylsiloxide), n-butylaluminum (tert-butoxide) (i-butyldimethylsiloxide), i-butylaluminum (methoxide) (trimethylsiloxide), i-butylaluminum (methoxide) (triethylsiloxide), i-butylaluminum (methoxide) (ethyldimethylsiloxide), i-butylaluminum (methoxide) (i-butyldimethylsiloxide), i-butylaluminum (ethoxide) (trimethylsiloxide),i-Butylaluminum (ethoxide) (triethylsiloxide), i-butylaluminum (ethoxide) (ethyldimethylsiloxide), i-butylaluminum (ethoxide) (i-butyldimethylsiloxide), i-butylaluminum (i-propoxide) (trimethylsiloxide), i-butylaluminum (i-propoxide) (triethylsiloxide), i-butylaluminum (i-propoxide) (ethyldimethylsiloxide), i-butylaluminum (i-propoxide) (i-butyldimethylsiloxide), i-butylaluminum (n-butoxide) (trimethylsiloxide), i-butylaluminum (n-butoxide) (triethylsiloxide), i-butylaluminum (n-butoxide) (ethyldimethylsiloxide) tylsiloxide), i-butylaluminum (n-butoxide) (i-butyldimethylsiloxide), i-butylaluminum (i-butoxide) (trimethylsiloxide), i-butylaluminum (i-butoxide) (triethylsiloxide), i-butylaluminum (i-butoxide) (ethyldimethylsiloxide), i-butylaluminum (i-butoxide) (i-butyldimethylsiloxide), i-butylaluminum (tert-butoxide) (trimethylsiloxide), i-butylaluminum (tert-butoxide) (triethylsiloxide), i-butylaluminum (tert-butoxide) (ethyldimethylsiloxide), i-butylaluminum (tert-butoxide) (i-butyldimethylsiloxide),

[0080] n-Hexylaluminum (methoxide) (trimethylsiloxide), n-Hexylaluminum (methoxide) (triethylsiloxide), n-Hexylaluminum (methoxide) (ethyldimethylsiloxide), n-Hexylaluminum (methoxide) (i-butyldimethylsiloxide), n-Hexylaluminum (ethoxide) (trimethylsiloxide), n-Hexylaluminum (ethoxide) (triethylsiloxide), n-Hexylaluminum (ethoxide) (ethyldimethylsiloxide), n-Hexylaluminum (ethoxide) oxide) (i-butyldimethylsiloxide), n-hexylaluminum (i-propoxide) (trimethylsiloxide), n-hexylaluminum (i-propoxide) (triethylsiloxide), n-hexylaluminum (i-propoxide) (ethyldimethylsiloxide), n-hexylaluminum (i-propoxide) (i-butyldimethylsiloxide), n-hexylaluminum (n-butoxide) (trimethylsiloxide), n-hexylaluminum (n-butoxide) (triethylsiloxide), n-hexylaluminum ( n-Butoxide) (ethyldimethylsiloxide), n-Hexylaluminum (n-butoxide) (i-butyldimethylsiloxide), n-Hexylaluminum (i-butoxide) (trimethylsiloxide), n-Hexylaluminum (i-butoxide) (triethylsiloxide), n-Hexylaluminum (i-butoxide) (ethyldimethylsiloxide), n-Hexylaluminum (i-butoxide) (i-butyldimethylsiloxide), n-Hexylaluminum (tert-butoxide) (trimethylsiloxide), n-Hexylaluminum Aluminum tert-butoxide (triethylsiloxide), n-hexylaluminum tert-butoxide (ethyldimethylsiloxide), n-hexylaluminum tert-butoxide (i-butyldimethylsiloxide), n-hexylaluminum tert-butoxide (phenyldimethylsiloxide), n-octylaluminum methoxide (trimethylsiloxide), n-octylaluminum methoxide (triethylsiloxide), n-octylaluminum methoxide (ethyldimethylsiloxide),n-Octyl aluminum (methoxide) (i-butyldimethylsiloxide), n-octylaluminum (ethoxide) (trimethylsiloxide), n-octylaluminum (ethoxide) (triethylsiloxide), n-octylaluminum (ethoxide) (ethyldimethylsiloxide), n-octylaluminum (ethoxide) (i-butyldimethylsiloxide), n-octylaluminum (i-propoxide) (trimethylsiloxide), n-octylaluminum (i-propoxide) (triethylsiloxide), n-octylaluminum (i-propoxide) (ethyldimethylsiloxide), n-octylaluminum (i-propoxide) (i-butyldimethylsiloxide), n-octylaluminum (n-butoxide) (trimethylsiloxide), n-octylaluminum (n-butoxide) (triethylsiloxide) siloxide), n-octylaluminum (n-butoxide) (ethyldimethylsiloxide), n-octylaluminum (n-butoxide) (i-butyldimethylsiloxide), n-octylaluminum (i-butoxide) (trimethylsiloxide), n-octylaluminum (i-butoxide) (triethylsiloxide), n-octylaluminum (i-butoxide) (ethyldimethylsiloxide), n-octylaluminum Examples of such aluminum compounds include aluminum i-butoxide (i-butyldimethylsiloxide), n-octylaluminum tert-butoxide (trimethylsiloxide), n-octylaluminum tert-butoxide (triethylsiloxide), n-octylaluminum tert-butoxide (ethyldimethylsiloxide), and n-octylaluminum tert-butoxide (i-butyldimethylsiloxide).

[0081] The aluminum compound represented by the general formula (1) is, in particular, an aluminum compound represented by the general formula (1) in which R 21 At least one of R is an alkyl group having 1 to 12 carbon atoms, and 21 At least one of R may be an alkoxy group having 1 to 12 carbon atoms; 21 At least one of R is an alkyl group having 1 to 8 carbon atoms, and 21At least one of R may be an alkoxy group having 1 to 8 carbon atoms; 21 At least one of R is an alkyl group having 1 to 6 carbon atoms, and 21 At least one of them may be an alkoxy group having 1 to 6 carbon atoms. In terms of catalytic activity and other catalytic performance, the aluminum compound represented by the general formula (1) is particularly preferred when R 21 are each independently an alkyl group having 1 to 6 carbon atoms, and R 21 One of them may be an alkoxy group having 1 to 6 carbon atoms.

[0082] The organoaluminum compound represented by the general formula (1) can be produced by a conventionally known method, or a commercially available product may be selected and used. When the organoaluminum compound represented by the general formula (1) has an alkoxy group, an aryloxy group, or a siloxy group, it can be produced by, for example, a method of reacting a trialkylaluminum with an alcohol, a silanol, or a phenol, respectively, or a method of reacting a dialkylaluminum halide with a metal alkoxide, a metal siloxide, or a metal phenoxide, respectively.

[0083] These reactions are preferably carried out in an inert hydrocarbon such as hexane, heptane, octane, decane, cyclohexane, benzene, toluene, or xylene. The reaction temperature may be any temperature that allows the reaction to proceed, but is preferably 0°C or higher, more preferably 20°C or higher. Heating the reaction above the boiling point of the solvent used and carrying out the reaction under solvent reflux is a good method for completing the reaction. The reaction time may be any, but is preferably 1 hour or longer, more preferably 2 hours or longer. After the reaction is complete, the reaction product may be cooled and subjected to a reaction with a chromium catalyst as a solution, or the solvent may be removed to isolate the reaction product; however, using the solution as is is convenient and preferred. The synthesis methods and physical and chemical properties of these organoaluminum compounds are described in detail in, for example, T. Mole et al., Organoaluminum Compounds, 3rd ed., 1972, Elsevier. Furthermore, the organoaluminum compound may be appropriately selected and used from those described in, for example, JP-A Nos. 2002-020412, 2003-096127, and 2003-183287.

[0084] The aluminum oxy compound represented by the general formula (2-1) and the aluminum oxy compound represented by the general formula (2-2) are compounds having an Al-O-Al bond in the molecule.

[0085] In the aluminum oxy compound represented by (2-1), n ​​is an integer of 0 or more. In the aluminum oxy compound represented by (2-1), when n=0, (R 22 )2Al-O-Al(R 22 )2. In the above (2-1), n ​​may be an integer of 1 or more, an integer of 2 or more, an integer of 100 or less, an integer of 50 or less, or an integer of 30 or less. In addition, in the above (2-2), m is an integer of 2 or more, and may be an integer of 100 or less, an integer of 50 or less, or an integer of 30 or less.

[0086] The aluminum oxy compound represented by the general formula (2-1) and the aluminum oxy compound represented by the general formula (2-2) are, among others, those represented by the general formula (2-1) and (2-2) in terms of industrial availability, 22 may each independently be an alkyl group having 1 to 12 carbon atoms, an alkyl group having 1 to 8 carbon atoms, or an alkyl group having 1 to 6 carbon atoms. The aluminum oxy compound represented by the general formula (2-1) and the aluminum oxy compound represented by the general formula (2-2) are, among others, those represented by the general formula (2-1) and (2-2) in terms of industrial availability, 22may each independently be a methyl group, an ethyl group, an n-butyl group, or an i-butyl group.

[0087] Such aluminum oxy compounds represented by the general formula (2-1) and aluminum oxy compounds (aluminoxane compounds) represented by the general formula (2-2) are usually products obtained by reacting an organoaluminum compound with water. The reaction of an organoaluminum compound with water is usually carried out in an inert hydrocarbon (solvent). Examples of the inert hydrocarbon that can be used include aliphatic hydrocarbons, alicyclic hydrocarbons, and aromatic hydrocarbons such as pentane, hexane, heptane, cyclohexane, methylcyclohexane, benzene, toluene, and xylene, but it is preferable to use an aliphatic hydrocarbon or an aromatic hydrocarbon.

[0088] The organoaluminum compounds used for preparing the aluminum oxy compound represented by the general formula (2-1) and the aluminum oxy compound represented by the general formula (2-2) can be appropriately selected from those listed for the aluminum compound represented by the general formula (1). The organoaluminum compound used to prepare the aluminum oxy compound represented by the general formula (2-1) and the aluminum oxy compound represented by the general formula (2-2) may be any of monoalkylaluminum, dialkylaluminum, and trialkylaluminum, but is preferably trialkylaluminum. The alkyl group of the trialkylaluminum can be any of a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an i-butyl group, an n-pentyl group, an n-hexyl group, an n-octyl group, an n-decyl group, an n-dodecyl group, and the like. The above organoaluminum compounds can also be used in combination of two or more. Those prepared from trimethylaluminum and alkylaluminum other than trimethylaluminum are also called modified methylaluminoxanes (MMAO). The ratio of trimethylaluminum to alkylaluminum other than trimethylaluminum can be appropriately selected. Preferably, the molar ratio of trialkylaluminum other than trimethylaluminum to trimethylaluminum is 1 / 9 to 9 / 1.

[0089] In the present invention, the aluminum oxy compound is preferably a modified methylaluminoxane prepared from trimethylaluminum and an alkylaluminum other than trimethylaluminum, from the viewpoint of improving activity, and more preferably a modified methylaluminoxane prepared from trimethylaluminum and triisobutylaluminum. An example of a commercially available product is the MMAO-3A grade manufactured by Toso Finechem Corporation, which uses trimethylaluminum and triisobutylaluminum.

[0090] The reaction ratio of water to organoaluminum compound (water / Al molar ratio) when producing the aluminum oxy compound is preferably 0.25 / 1 to 1.2 / 1, particularly 0.5 / 1 to 1 / 1, and the reaction temperature is usually −70 to 100° C., preferably −20 to 20° C. The reaction time is usually selected from the range of 5 minutes to 24 hours, preferably 10 minutes to 5 hours. The water required for the reaction may not only be simple water, but also water of crystallization contained in copper sulfate hydrate, aluminum sulfate hydrate, etc., or components that can generate water in the reaction system.

[0091] [A mixture of a chromium catalyst (A), a reducing organosilicon compound (B), and an organoaluminum compound (C)] In step (2), the chromium catalyst (A), the reducing organosilicon compound (B), and the organoaluminum compound (C) are mixed in an inert hydrocarbon solvent. The method for mixing the chromium catalyst (A), the reducing organosilicon compound (B), and the organoaluminum compound (C) in an inert hydrocarbon solvent is not particularly limited. Examples of the inert hydrocarbon solvent that can be used include propane, n-butane, isobutane, n-pentane, isopentane, hexane, heptane, octane, decane, cyclohexane, benzene, toluene, and xylene.

[0092] The amount of the inert hydrocarbon solvent used is preferably an amount that allows stirring at least in a slurry state during mixing. As long as it is an amount like this, the amount of the inert hydrocarbon solvent used is not particularly limited, but for example, 2 to 20 g of the solvent can be used per 1 g of the chromium catalyst (A) after calcination activation.

[0093] The mixing method may be such that the chromium catalyst (A) is mixed with an inert hydrocarbon solvent to form a slurry, to which the reducing organosilicon compound (B) is added and then the organoaluminum compound (C) is added, or the organoaluminum compound (C) is added and then the reducing organosilicon compound (B) is added, or the reducing organosilicon compound (B) and the organoaluminum compound (C) may be added simultaneously. The preferred mixing method is to mix the chromium catalyst (A) with an inert hydrocarbon solvent to form a slurry, add the reducing organosilicon compound (B) to the slurry, and then add the organoaluminum compound (C), in order to increase not only the high-molecular-weight components but also the low-molecular-weight components. Furthermore, the preferred method is to mix the chromium catalyst (A) with an inert hydrocarbon solvent to form a slurry, add the organoaluminum compound (C) to the slurry, and then add the reducing organosilicon compound (B), in order to increase activity. The reducing organosilicon compound (B) and organoaluminum compound (C) may be added either diluted with the above-mentioned inert hydrocarbon solvent or without dilution. The solvent used for mixing with the dilution solvent may be the same or different. If the organosilicon compound (B) having reducing properties is a solid substance, the reaction may be carried out by mixing the chromium catalyst (A) and the organosilicon compound (B) and then adding an inert hydrocarbon solvent. By mixing and contacting the calcined and activated chromium catalyst (A) with the reducing organosilicon compound (B) in an inert hydrocarbon solvent, at least some of the hexavalent chromium atoms in the chromium catalyst (A) are reduced by the reducing organosilicon compound (B).

[0094] Examples of methods for mixing the chromium catalyst (A), the organosilicon compound (B) having reducing properties, and the organoaluminum compound (C) include the following. (i) A method in which an organoaluminum compound (C) is added to a slurry obtained by mixing a chromium catalyst (A) and an organosilicon compound (B) having reducing properties; (ii) A method in which a solution of an organoaluminum compound (C) is mixed with a mixture of the chromium catalyst (A) and the organosilicon compound (B) having reducing properties, obtained by removing the solvent from the slurry obtained after mixing the chromium catalyst (A) and the organosilicon compound (B) having reducing properties; (iii) A method in which a reducing organosilicon compound (B) is added to a slurry obtained by mixing a chromium catalyst (A) and an organoaluminum compound (C); (iv) A method in which a solution of an organosilicon compound (B) having reducing properties is mixed with a mixture of the chromium catalyst (A) and the organoaluminum compound (C) obtained by removing the solvent from the slurry after mixing the chromium catalyst (A) and the organoaluminum compound (C); (v) A method in which a reducing organosilicon compound (B) and an organoaluminum compound (C) are simultaneously added to a slurry of a chromium catalyst (A). The mixing method is preferably the above-mentioned methods (i) and (ii), and more preferably the above-mentioned method (ii).

[0095] The amount of the reducing organosilicon compound (B) mixed with the chromium catalyst (A) may be 0.001 to 100, or 0.01 to 10, preferably 0.01 to 4, more preferably 0.05 to 4, and even more preferably 0.1 to 1, expressed as a molar ratio ([B] / [Cr]) of the amount of the organosilicon compound (B) relative to the chromium atoms contained in the chromium catalyst (A). This molar ratio is preferred because the effects of using the reducing organosilicon compound (B) are fully exhibited. The amount of high-molecular-weight polymer components present during the production of an ethylene polymer can be appropriately adjusted by adjusting the amount of the organosilicon compound (B) relative to the amount of the chromium catalyst (A).

[0096] The concentration of the chromium catalyst (A) in the solvent when mixed with the reducing organosilicon compound (B) is preferably 0.01 g / mL to 0.3 g / mL, more preferably 0.05 g / mL to 0.2 g / mL, and even more preferably 0.1 g / mL to 0.2 g / mL. The concentration of the reducing organosilicon compound (B) is preferably 1.0 mM to 5.0 M, more preferably 2.0 mM to 1.0 M, and even more preferably 5.0 mM to 0.5 M. The temperature during mixing is preferably -20°C to 150°C, more preferably -10°C to 100°C, and even more preferably 0°C to 80°C, and the mixing time is preferably 5 minutes to 12 hours, more preferably 30 minutes to 10 hours, and even more preferably 1 to 8 hours.

[0097] The amount of the organoaluminum compound (C) mixed with the chromium catalyst (A) may be such that the ratio of aluminum atoms in the organoaluminum compound (C) to chromium atoms in the chromium catalyst (A) in terms of molar ratio ([Al] / [Cr]) is 0.01 to 100, or 0.1 to 10, and more preferably 0.5 to 5. This molar ratio within the above range is preferred because the effects of using the organoaluminum compound (C) are fully exhibited. The molecular weight distribution and catalytic activity during the production of an ethylene polymer can be appropriately adjusted by adjusting the amount of the organoaluminum compound (C) used relative to the chromium catalyst (A).

[0098] Regarding the concentration of the chromium catalyst (A) and the organoaluminum compound (C) in the solvent when they are mixed, the concentration of the chromium catalyst (A) is preferably 0.01 g / mL to 0.3 g / mL, more preferably 0.05 g / mL to 0.2 g / mL, and even more preferably 0.1 g / mL to 0.2 g / mL, and the concentration of the organoaluminum compound (C) is preferably 1.0 mM to 5.0 M, more preferably 2.0 mM to 1.0 M, and even more preferably 5.0 mM to 0.5 M. The temperature during mixing is preferably -20°C to 150°C, more preferably -10°C to 100°C, and even more preferably 0°C to 80°C, and the mixing time is preferably 5 minutes to 12 hours, more preferably 30 minutes to 10 hours, and even more preferably 1 to 8 hours.

[0099] The mixing ratio of the organosilicon compound (B) having reducing properties and the organoaluminum compound (C) may be appropriately selected according to the desired molecular weight distribution. The molar ratio ([Al] / [B]) of aluminum atoms in the organoaluminum compound (C) to the reducing organosilicon compound (B) may be 0.05 to 20, 0.1 to 10, or 0.2 to 5. This molar ratio within the above range is preferred because the effects of using the reducing organosilicon compound (B) are fully exhibited and the molecular weight distribution can be adjusted. Depending on the amount of the organoaluminum compound (C) used relative to the organosilicon compound (B), the amount of high molecular weight polymer components present, the molecular weight distribution, and catalytic activity during the production of an ethylene polymer can be appropriately adjusted.

[0100] 3. Other processes In step (2), it is preferable to quickly remove the inert hydrocarbon solvent after the mixing operation is completed. The solvent can be removed by passing an inert gas such as nitrogen through the mixture, or by reducing the pressure. Among these, drying under reduced pressure is preferred, and filtration may be used in combination. In the case of drying under reduced pressure, it is preferable to dry the mixture so that the resulting ethylene polymerization catalyst (the chromium catalyst modified with the organosilicon compound (B)) is obtained as a powder that is free from viscosity and moisture and has good flowability. As a guideline for physical properties, the remaining mass of the solvent is preferably 1 / 2 or less, preferably 1 / 5, and more preferably 1 / 10 or less of the mass obtained by multiplying the pore volume of the obtained ethylene polymerization catalyst by the density of the solvent. Here, the pore volume is determined by the BET method using nitrogen adsorption, and the remaining mass of the solvent can be calculated by the following formula. Residual mass of solvent = (mass of ethylene polymerization catalyst after drying) - {(mass of the organosilicon compound (B)) + (mass of the chromium catalyst (A))} If the catalyst is stored for a long time without being separated from the solvent, the catalyst may deteriorate over time, resulting in a decrease in ethylene polymerization activity. Therefore, it is preferable to minimize the contact time with the solvent, including the contact time with the solvent during the supported reaction, and to quickly remove and dry the solvent.

[0101] After the completion of the supporting reaction, the time required to separate the solvent and complete drying is preferably within 20 hours, more preferably within 15 hours.

[0102] II. Method for producing ethylene polymers The method for producing an ethylene polymer of the present invention is characterized in that ethylene homopolymerization or copolymerization of ethylene and an α-olefin is carried out using the ethylene polymerization catalyst obtained by the production method of the present invention, and the ethylene polymerization catalyst is used without being calcined in a non-reducing atmosphere. In the process for producing an ethylene polymer of the present invention, after the step (2) of mixing the chromium catalyst (A), the organosilicon compound (B) having reducibility, and the organoaluminum compound (C), the resulting ethylene polymerization catalyst is used for ethylene homopolymerization or ethylene copolymerization with an α-olefin without calcination in a non-reducing atmosphere. Note that the calcination in a non-reducing atmosphere here refers to a step of calcining at about 300°C to 950°C in a non-reducing atmosphere, similar to the "activation by calcination in a non-reducing atmosphere" described in the step (1). The process for producing an ethylene polymer of the present invention can produce a high-molecular-weight ethylene polymer by using the ethylene polymerization catalyst obtained by the production process of the present invention without calcining it in a non-reducing atmosphere.

[0103] When producing an ethylene polymer using the ethylene polymerization catalyst, any method can be employed, such as a liquid phase polymerization method such as slurry polymerization or solution polymerization, or a gas phase polymerization method. Liquid-phase polymerization is usually carried out in a hydrocarbon solvent, such as propane, n-butane, isobutane, n-pentane, isopentane, hexane, heptane, octane, decane, cyclohexane, benzene, toluene, or xylene, either alone or in mixtures. The gas phase polymerization method can be a commonly known polymerization method such as a fluidized bed or stirred bed in the presence of an inert gas, and in some cases, a so-called condensing mode can be used in the presence of a medium for removing polymerization heat.

[0104] The polymerization temperature in liquid-phase or gas-phase polymerization is generally 0 to 300°C, and practically 20 to 200°C, preferably 50 to 180°C, and more preferably 70 to 150°C. The catalyst concentration and ethylene concentration in the reactor may be any concentration sufficient to allow polymerization to proceed. For example, in the case of liquid-phase polymerization, the catalyst concentration can be in the range of about 0.0001 to about 5 mass% based on the mass of the reactor contents. Similarly, in the case of gas-phase polymerization, the ethylene concentration can be in the range of 0.1 to 10 MPa in terms of total pressure.

[0105] The polymerization method according to the present invention can be a single-stage polymerization method for producing polyethylene using one reactor, or a multi-stage polymerization method using at least two reactors connected together to broaden the molecular weight distribution. In the case of multi-stage polymerization, two reactors may be connected together, and a two-stage polymerization method may be used in which the reaction mixture obtained by polymerization in the first-stage reactor is continuously fed to the second-stage reactor. The transfer from the first-stage reactor to the second-stage reactor is carried out by continuously discharging the polymerization reaction mixture from the first-stage reactor through a connecting pipe due to a pressure difference.

[0106] When polymerizing ethylene by the method of the present invention, an α-olefin may be copolymerized as a comonomer. As the α-olefin, propylene, 1-butene, 1-hexene, 4-methyl-1-pentene, 1-octene, or the like may be introduced alone or in combination with two or more kinds into a reactor and copolymerized. Preferably, 1-butene or 1-hexene, more preferably 1-hexene, is used as the comonomer. The α-olefin content in the resulting ethylene copolymer is desirably 15 mol % or less, preferably 10 mol % or less.

[0107] The ethylene polymer obtained by the ethylene polymerization catalyst obtained by the production method of the present invention may be further kneaded, which results in a more homogenized ethylene polymer. The homogenization operation can be carried out using a single-screw or twin-screw extruder or a continuous kneader. During kneading, conventionally known additives and the like can be added.

[0108] The ethylene polymer obtained by the ethylene polymerization catalyst obtained by the production method of the present invention has a wide molecular weight distribution, and a high molecular weight ethylene polymer suitable for practical use can be obtained. By using the ethylene polymerization catalyst obtained by the method for producing an ethylene polymerization catalyst according to the present invention, it is possible to obtain an ethylene polymerization catalyst having an HLMFR of preferably 0.1 g / 10 min to 200 g / 10 min, more preferably 0.3 g / 10 min to 100 g / 10 min, and a density of preferably 0.935 g / cm 3 ~0.970g / cm 3 , more preferably 0.940 g / cm 3 ~0.960g / cm 3 With a Phillips catalyst, the HLMFR is generally controlled by the polymerization temperature. Increasing the polymerization temperature increases the HLMFR, and decreasing the polymerization temperature decreases the HLMFR. The density is also controlled by the comonomer concentration. A high comonomer concentration results in a low density, and a low comonomer concentration results in a high density. Furthermore, an ethylene polymer having a weight average molecular weight Mw measured by gel permeation chromatography (GPC) of preferably 100,000 to 800,000, more preferably 200,000 to 500,000, and a molecular weight distribution (Mw / Mn) of preferably 10 or more and 60 or less, more preferably 15 or more and 40 or less can be obtained.

[0109] The resulting ethylene polymer has an increased proportion of polymer components on the high molecular weight side, and also has a change in the proportion of components on the relatively low molecular weight side, so that a material excellent in impact resistance and durability can be provided while maintaining fluidity. The resulting ethylene polymer can be easily blow-molded by a conventional method to obtain a blow-molded article, and large blow-molded articles can also be obtained in the same manner. The above-mentioned properties are particularly suitable for large-scale blow molding. [Example]

[0110] The present invention will now be described in more detail with reference to examples, but the present invention is not limited to the following examples as long as the gist of the invention is not exceeded. The physical property measurements and analyses in the following examples were carried out according to the following methods. Unless otherwise specified, room temperature is 25°C.

[0111] (I) Various measurement methods The measurement methods used in the examples and comparative examples are as follows. (1) Polymer pretreatment for physical property measurements: To the obtained polymer, 0.2 wt % of "IRGANOX B225", a blend of antioxidant and phosphorus-based stabilizer manufactured by BASF Japan Ltd., was added as an additive, and the mixture was kneaded and pelletized in a single-screw extruder. (2) High Load Melt Flow Rate (HLMFR): In accordance with JIS K7210 (2004 edition), Appendix A, Table 1, Condition G, the measured value at a test temperature of 190°C and a nominal load of 21.60 kg was shown as HLMFR. (3) Density: Measurements were carried out in accordance with JIS K7112 (2004 edition).

[0112] (4) Molecular weight distribution curve: Gel permeation chromatography (GPC) was performed under the conditions shown below, and the number average molecular weight (Mn) and weight average molecular weight (Mw) were measured by converting the retention volume into molecular weight, and the molecular weight distribution (Mw / Mn) was calculated. [GPC equipment, measurement conditions] Apparatus: Agilent Technologies GPC (PL-GPC220) Detector: IR detector Column: Showa Denko AT806MS (3 columns in series) Mobile phase solvent: o-dichlorobenzene (ODCB) Measurement temperature: 140℃ Flow rate: 1.0mL / min Injection volume: 0.3mL The sample was dissolved in ODCB (containing 0.24 mg / mL of 2,4,6-trimethylphenol (TMP)) at 140° C. for about 1 hour to prepare a sample solution with a concentration of 0.25 mg / mL. [Conversion of retention volume to molecular weight] The conversion from retention volume to molecular weight was performed using a calibration curve prepared in advance using standard polystyrenes, all of which were the following brands manufactured by Tosoh Corporation. F380, F288, F128, F80, F40, F20, F10, F4, F1, A5000, A2500, A1000. A calibration curve is created by injecting 0.3 mL of a solution of each standard polystyrene dissolved in ODCB (containing 0.24 mg / mL of TMP) so that the concentration is 0.5 mg / mL. The calibration curve uses a cubic equation obtained by approximating using the least squares method. The viscosity equation used for conversion to molecular weight is [η] = K × M α The following values ​​are used: PS:K = 1.38 × 10 -4 , α=0.700 PE:K = 3.92 × 10 -4 , α=0.733 PP:K = 1.03 × 10 -4 , α=0.780

[0113] (5) UV-Vis-NIR analysis of solid catalysts For each solid catalyst, UV-Vis-NIR measurement was carried out under the following conditions. [UV-Vis-NIR equipment, measurement conditions] Spectral analysis of the solid catalyst was carried out using an ultraviolet-visible spectrophotometer (product name "UV-2600", manufactured by Shimadzu Corporation). To detect the near-infrared region, an ISR-2600Plus integrating sphere attachment was installed on the UV-visible spectrophotometer. The measurement conditions were a wavelength range of 300-1400 nm, and barium sulfate was used as the reference. The solid catalyst sample was placed in a quartz cell with an optical path length of 1 mm and analyzed. According to BMWckhuysen et al., Chem.Rev.1996,96,pp.3327-3349, it is assigned as follows: Chromate CT transition: 243-277nm, 333-370nm Polychromate CT transition: 243-277nm, 435-476nm Pseudo-octahedral Cr 3+ (including Cr2O3) dd transition: 588-666 nm Pseudo-octahedral Cr 2+ DD transition: 770-1000nm pseudo-tetrahedral Cr 2+ DD transition: 1000-1430nm

[0114] (II) Examples and Comparative Examples [Example 1] 1. Step (1): Preparation of Chromium Catalyst (A) 10 g of silica as an inorganic oxide support (a) and 0.44 g of chromium acetate as a chromium compound (b) were added to a chromium acetate ethanol solution prepared by dissolving them in 50 ml of ethanol, and after stirring for 10 minutes, the ethanol was distilled off to obtain a chromium-containing silica having a chromium atom loading of 1.0 wt %. This chromium-containing silica had a specific surface area of ​​380 m 2 / g, pore volume 1.55 cm 3 The chromium-containing silica was then placed in a quartz glass tube with a diameter of 5 cm and fitted with a perforated plate, which was then placed in a cylindrical electric furnace for calcination. The tube was fluidized with air passed through molecular sieves and calcined for 18 hours at a linear velocity of 3 cm / s at 500°C. As a result, an orange chromium catalyst (A), which indicates the presence of hexavalent chromium atoms, was obtained.

[0115] 2. Step (2): Preparation of chromium catalyst (catalyst-1A) treated with organosilicon compound (B) and organoaluminum (C) A 100 mL flask previously purged with nitrogen was charged with 2.0 g of the chromium catalyst (A) obtained in step (1) above, and 14 mL of distilled and purified hexane was added to form a slurry. 10 mL of a hexamethyldisilane solution (0.2 M), an organosilicon compound (B) ([B] / Cr molar ratio = 5), was added and stirred at 40°C for 1 hour. Immediately after stirring, the solvent was removed under reduced pressure over 30 minutes to yield a free-flowing chromium catalyst (catalyst-1) with no viscosity or stickiness. Figure 1 shows the results of UV-Vis-NIR analysis of the resulting catalyst-1. Next, 1.0 g of catalyst-1 was placed in a 100 ml flask purged with nitrogen, and 7 ml of distilled and purified hexane was added to form a slurry. 4 ml of a 0.5 mol / L hexane solution of diethylaluminum ethoxide (EtAl(OEt)) as organoaluminum compound (C) was added (Al / Cr molar ratio = 5), and the mixture was stirred at 40°C for 1 hour. Immediately after stirring, the solvent was removed under reduced pressure over 30 minutes to obtain a chromium catalyst (catalyst-1A) treated with organosilicon compound (B) and organoaluminum compound (C).

[0116] 3. Ethylene Polymerization Evaluation A 2.0 L autoclave, thoroughly purged with nitrogen, was charged with 217 mg of catalyst 1A obtained in step (2) above and 0.7 L of isobutane, and the internal temperature was raised to 100°C. Ethylene was then injected, and polymerization was carried out while maintaining the ethylene partial pressure at 1.4 MPa until the yield (g) of ethylene polymer per g of catalyst reached approximately 700 (polymerization time: 110 minutes). The polymerization was terminated by releasing the gas from the system. The polymerization results and polymer properties are shown in Table 1. The results of the molecular weight distribution measurement are shown in FIG.

[0117] [Example 2] 1. Step (1): Preparation of Chromium Catalyst (A) The chromium catalyst (A) obtained in step (1) of Example 1 was used. 2. Step (2): Preparation of Chromium Catalyst (Catalyst-2A) Catalyst-1 obtained in Example 1 was used as the chromium catalyst treated with organosilicon compound (B). 1.0 g of catalyst-1 was placed in a 100 ml flask purged with nitrogen, and 7 ml of distilled and purified hexane was added to form a slurry. 4 ml of a 0.5 mol / L hexane solution of MMAO-3A (modified methylaluminoxane (raw materials: trimethylaluminum and triisobutylaluminum), obtained from Tosoh Finechem Co., Ltd.) as organoaluminum compound (C) was added (Al / Cr molar ratio = 5), and the mixture was stirred at 40°C for 1 hour. Immediately after stirring, the solvent was removed under reduced pressure over 30 minutes to obtain a chromium catalyst (catalyst-2A) treated with organosilicon compound (B) and organoaluminum compound (C). 3. Ethylene Polymerization Evaluation Polymerization was carried out in the same manner as in Example 1, except that 236 mg of catalyst 2A was used instead of catalyst 1A and the polymerization time was 112 minutes in the evaluation of ethylene polymerization in Example 1. The polymerization results and polymer properties are shown in Table 1. The results of the molecular weight distribution measurement are shown in FIG.

[0118] [Comparative Example 1] 1. Step (1): Preparation of Chromium Catalyst (A) The chromium catalyst (A) was used, obtained in step (1) of Example 1. The results of UV-Vis-NIR measurement of the chromium catalyst (A) are shown in FIG. 2. Step (2) was not performed. 3. Ethylene Polymerization Evaluation Polymerization was carried out in the same manner as in Example 1, except that 74 mg of the chromium catalyst (A) obtained in step (1) of Example 1 was used and the polymerization time was changed to 63 minutes in the ethylene polymerization evaluation of Example 1. The polymerization results and polymer properties are shown in Table 1. The results of the molecular weight distribution measurement are shown in FIG.

[0119] [Example 3] 1. Step (1): Preparation of Chromium Catalyst (A2) EP30X (chromium-containing silica with a chromium atom loading of 1.0 wt %) manufactured by Ineos Silicas was placed in a quartz glass tube with a diameter of 5 cm and a perforated plate, which was then placed in a cylindrical electric furnace for calcination. The tube was fluidized with air passed through molecular sieves and calcined for 18 hours at a linear velocity of 4 cm / s and 820°C. As a result, an orange-colored chromium catalyst (A2), which indicates the presence of hexavalent chromium atoms, was obtained. 2. Step (2): Preparation of chromium catalyst (catalyst-3A) treated with organosilicon compound (B) and organoaluminum (C) A 100 mL flask previously purged with nitrogen was charged with 2.0 g of the chromium catalyst (A2) obtained in step (1) above, and 14 mL of distilled and purified hexane was added to form a slurry. 1.9 mL of a hexamethyldisilane solution (0.2 M), which is the organosilicon compound (B) ([B] / Cr molar ratio = 1), was added to the flask, and the mixture was stirred at 40°C for 1 hour. Immediately after stirring, the solvent was removed under reduced pressure over 30 minutes, yielding a free-flowing chromium catalyst (Catalyst-3) that was neither viscous nor sticky. Next, 1.0 g of catalyst-3 was placed in a 100 ml flask purged with nitrogen, and 7 ml of distilled and purified hexane was added to form a slurry. 1.9 ml of a 0.2 mol / L hexane solution of diethylaluminum ethoxide (EtAl(OEt)) as organoaluminum compound (C) was added (Al / Cr molar ratio = 2), and the mixture was stirred at 40°C for 1 hour. Immediately after stirring, the solvent was removed under reduced pressure over 30 minutes to obtain a chromium catalyst (catalyst-3A) treated with organosilicon compound (B) and organoaluminum compound (C). 3. Ethylene Polymerization Evaluation A 2.0 L autoclave, thoroughly purged with nitrogen, was charged with 122 mg of catalyst 3A obtained in step (2) above, 3.2 g of 1-hexene, and 0.7 L of isobutane, and the internal temperature was raised to 100°C. Ethylene was then injected, and polymerization was carried out while maintaining the ethylene partial pressure at 1.4 MPa until the yield (g) of ethylene polymer per g of catalyst reached approximately 600 (polymerization time: 33 minutes). The polymerization was terminated by releasing the gas from the system. The polymerization results and polymer properties are shown in Table 2. The results of the molecular weight distribution measurement are shown in FIG.

[0120] [Example 4] 1. Step (1): Preparation of Chromium Catalyst (A2) The chromium catalyst (A2) used in Example 3 was used as is. 2. Step (2): Preparation of chromium catalyst (catalyst-4A) treated with organosilicon compound (B) and organoaluminum (C) A 100 mL flask previously purged with nitrogen was charged with 2.0 g of the chromium catalyst (A2) obtained in step (1) above, and 14 mL of distilled and purified hexane was added to form a slurry. 3.8 mL of a 0.2 mol / L hexane solution of diethylaluminum ethoxide (EtAl(OEt)) as organoaluminum compound (C) was added (Al / Cr molar ratio = 2), and the mixture was stirred at 40°C for 1 hour. Immediately after stirring, the solvent was removed under reduced pressure over 30 minutes to yield a free-flowing chromium catalyst (Catalyst-4) that was neither viscous nor sticky. Next, 1.0 g of catalyst-4 was placed in a nitrogen-purged 100 ml flask and 7 ml of distilled and purified hexane was added to form a slurry. 0.95 mL of a hexamethyldisilane solution (0.2 M), which is the organosilicon compound (B) ([B] / Cr molar ratio = 1), was added and stirred at 40°C for 1 hour. Immediately after stirring, the solvent was removed under reduced pressure over 30 minutes to yield a chromium catalyst (catalyst-4A) treated with the organosilicon compound (B) and the organoaluminum compound (C). 3. Ethylene Polymerization Evaluation Polymerization was carried out in the same manner as in Example 3, except that 114 mg of catalyst 4A was used instead of catalyst 3A and the polymerization time was changed to 27 minutes in the evaluation of ethylene polymerization in Example 3. The polymerization results and polymer properties are shown in Table 2. The results of the molecular weight distribution measurement are shown in FIG.

[0121] Comparative Example 2 1. Step (1): Preparation of Chromium Catalyst (A2) The chromium catalyst (A2) obtained in step (1) of Example 3 was used. 2. Step (2) was not performed. 3. Ethylene Polymerization Evaluation Polymerization was carried out in the same manner as in Example 3, except that 102 mg of the chromium catalyst (A2) obtained in step (1) of Example 3 was used and the polymerization time was changed to 15 minutes in the ethylene polymerization evaluation of Example 3. The polymerization results and polymer properties are shown in Table 2. The results of the molecular weight distribution measurement are shown in FIG.

[0122] Comparative Example 3 1. Step (1): Preparation of Chromium Catalyst (A2) The chromium catalyst (A2) obtained in step (1) of Example 3 was used. 2. In step (2) of Example 3, catalyst-3 treated only with hexamethyldisilane was used. 3. Ethylene Polymerization Evaluation Polymerization was carried out in the same manner as in Example 3, except that in step (2) of Example 3, 100 mg of catalyst-3 treated only with hexamethyldisilane was used and the polymerization time was changed to 156 minutes in the ethylene polymerization evaluation of Example 3. The polymerization results and polymer properties are shown in Table 2.

[0123] [Evaluation results] Comparing the UV-Vis-NIR measurements of each solid catalyst, the chromium catalyst (A) used in Comparative Example 1, which is mainly composed of hexavalent chromium species, exhibited absorption due to the CT transitions of chromate and polychromate (248 nm and 467 nm), and no absorption was observed in the wavelength region longer than 600 nm. In contrast, in the case of catalyst-1 used in Examples 1 and 2, which was treated with hexamethyldisilane, the absorption of hexavalent chromium species decreased, and absorption at 770 to 1000 nm and 1000 to 1430 nm attributable to divalent chromium species was observed, indicating the progress of a reduction reaction from hexavalent chromium species to divalent chromium species. The absorption peak observed at 660 nm is difficult to distinguish because it is an absorption due to the dd transition of trivalent chromium species and Cr2O3, but it can be said to be due to a reduction reaction product that is not present in chromium catalyst (A).

[0124] [Table 1]

[0125] As can be seen from Table 1, when Examples 1 and 2 are compared with Comparative Example 1, the time taken to reach the equivalent product in Examples 1 and 2 is longer, and the catalytic activity tends to be lower, but the HLMFR is reduced, indicating an increase in the high molecular weight polymer component. 2, which shows the molecular weight distribution, shows that in Examples 1 and 2, which were treated with organosilicon compound (B) and organoaluminum compound (C), the proportion of high molecular weight components was clearly increased compared to Comparative Example 1, which was not treated. Furthermore, it was also shown that the type of organoaluminum compound (C) had different effects on the molecular weight peak position. That is, in Example 1, in which diethylaluminum ethoxide was used as the organoaluminum compound (C) in addition to the organosilicon compound (B), the proportion of high molecular weight components increased, while the molecular weight peak position shifted to the lower molecular weight side, compared to Comparative Example 1, in which no treatment was performed. In Example 2, in which MMAO was used as the organoaluminum compound (C) in addition to the organosilicon compound (B), the proportion of high molecular weight components increased significantly, and although the peak position of the low molecular weight components remained unchanged, the base of the low molecular weight components broadened. Comparison of Example 1 and Example 2 demonstrated that the molecular weight distribution can be adjusted by changing the type of organoaluminum compound (C) used.

[0126] [Table 2]

[0127] In Comparative Example 2, the activation temperature of the chromium catalyst was changed from 500°C to 820°C, as compared to Comparative Example 1. As shown in Table 2, in Examples 3 and 4, the combined use of the organosilicon compound (B) and the organoaluminum compound (C) increased the amount of high molecular weight components and reduced the HLMFR, compared to Comparative Example 2, in which step (2) was not performed. In other words, it was found that the organosilicon compound (B) and the organoaluminum compound (C) functioned effectively even when the activation temperature of the chromium catalyst was different. Furthermore, the results of Examples 3 and 4 show that the effect of increasing the high molecular weight component can be achieved even when the contact order of the organosilicon compound (B) and the organoaluminum compound (C) is reversed. When the organosilicon compound (B) is contacted first, as can be seen from Figure 3, it is possible to increase the low molecular weight component in addition to the high molecular weight component. On the other hand, contacting the organoaluminum compound (C) first has the advantage of high activity. Furthermore, when only the organosilicon compound (B) is added to the chromium catalyst (A) without the organoaluminum compound (C), the HLMFR decreases and the activity becomes significantly lower, as shown in Comparative Example 3. In contrast, as shown in Examples 3 and 4 of the present invention, by using the organosilicon compound (B) and the organoaluminum compound (C) in combination with the chromium catalyst (A), it was shown that a catalyst with sufficiently high activity can be obtained while reducing the HLMFR.

[0128] From the above, it has been demonstrated that in the chromium-supported catalyst obtained by the production method disclosed in the present invention, the organosilicon compound (B) and organoaluminum compound (C) having reducing properties are effective as modifiers for providing ethylene polymers with a controlled amount of polymer component, and are useful in controlling the molecular weight distribution of ethylene polymers. By mixing the calcined chromium catalyst with a reducing organosilicon compound (B) and an organoaluminum compound (C) as modifiers, it is possible to increase the amount of high-molecular-weight components as well as low-molecular-weight components with good catalytic activity, or to control both, thereby expanding the possibilities for controlling the molecular weight distribution. [Industrial Applicability]

[0129] According to the present invention, it is possible to provide a method for producing an ethylene polymerization catalyst and a method for producing an ethylene polymer, which are capable of producing an ethylene polymer having a broad molecular weight distribution and an increased content of high-molecular-weight components. As a result, the present invention makes it possible to produce an ethylene polymer having a broad molecular weight distribution and an increased content of high-molecular-weight components, and thus, it is possible to produce an ethylene polymer that is more suitable for the purpose than conventional methods, and therefore the present invention is of great industrial significance.

Claims

1. A method for producing an ethylene polymerization catalyst, comprising the following steps (1) and (2): Step (1): A step of supporting a chromium compound (b) on an inorganic oxide support (a) and calcining and activating the support in a non-reducing atmosphere to obtain a chromium catalyst (A). Step (2): A step of mixing the chromium catalyst (A), a reducing organosilicon compound (B), and an organoaluminum compound (C) in an inert hydrocarbon solvent.

2. 2. The method for producing an ethylene polymerization catalyst according to claim 1, wherein the organosilicon compound (B) has a first ionization potential capable of reducing the chromium compound (b).

3. 3. The method for producing an ethylene polymerization catalyst according to claim 1, wherein the organosilicon compound (B) has a first ionization potential of 5.5 to 8.0 eV.

4. 3. The method for producing an ethylene polymerization catalyst according to claim 1, wherein the organosilicon compound (B) is an organosilicon compound represented by the following general formula (I): 【Chemical 1】 [In formula (I), R １ , R ２ , R ３ , R ４ , R ５ and R ６ are each independently a hydrogen atom, a halogen atom, a hydrocarbon group having 1 to 30 carbon atoms, or a substituent containing at least one heteroatom selected from the group consisting of an oxygen atom, a sulfur atom, a nitrogen atom, a phosphorus atom, and a silicon atom, or １ , R ２ , R ３ , R ４ , R ５ and R ６ may be bonded to each other to form a cyclic structure, and the hydrocarbon group may have a substituent containing a halogen atom or at least one hetero atom selected from the group consisting of an oxygen atom, a sulfur atom, a nitrogen atom, a phosphorus atom, and a silicon atom. 【Chemistry 2】 [In formula (IIA) and formula (IIB), R １１ , R １１’ , R １１” , R １２ , R １３ , R １４ , and R １５ are each independently a hydrogen atom, a hydrocarbon group having 1 to 14 carbon atoms, or an aromatic heterocyclic group having 4 to 14 carbon atoms. 【Chemistry 3】 [In formula (IIIA) and formula (IIIB), R １１ , R １１’ , R １１” , R １２ , R １３ , R １４ , R １５ , R １６ and R １７ are each independently a hydrogen atom, a hydrocarbon group having 1 to 14 carbon atoms, or an aromatic heterocyclic group having 4 to 14 carbon atoms.

5. In the formula (I), R １ , R ２ , R ３ , R ４ , R ５ and R ６ are each independently a hydrocarbon group having 1 to 6 carbon atoms, and in formulas (IIA), (IIB), (IIIA), and (IIIB), R １１ , R １１’ , R １１” are each independently an alkyl group having 1 to 10 carbon atoms, and R １２ , R １３ , R １４ , R １５ are each independently a hydrogen atom or an alkyl group having 1 to 10 carbon atoms, and R １６ and R １７ The method for producing an ethylene polymerization catalyst according to claim 1 or 2, wherein is a hydrogen atom.

6. 3. The method for producing an ethylene polymerization catalyst according to claim 1, wherein the amount of the organosilicon compound (B) used in step (2) relative to the chromium atoms contained in the chromium catalyst (A) is 0.001 to 100 in terms of a molar ratio ([B] / [Cr]).

7. 3. The method for producing an ethylene polymerization catalyst according to claim 1, wherein the organoaluminum compound (C) is at least one selected from the group consisting of an aluminum compound represented by the following general formula (1), an aluminum oxy compound represented by the following general formula (2-1), and an aluminum oxy compound represented by the following general formula (2-2): General formula (1): AlR ２１ ３ (In formula (1), R ２１ are each independently an alkyl group, an alkoxy group, an aryloxy group, or a siloxy group, and may be the same or different from one another, and the aryloxy group may be substituted with an alkyl group, a halogen atom, an alkoxy group, or a nitrile group. 【Chemistry 4】 (In formulas (2-1) and (2-2), R ２２ are each independently an alkyl group, an alkoxy group, an aryloxy group, or a siloxy group, and may be the same or different from one another, and the aryloxy group may be substituted with an alkyl group, a halogen atom, an alkoxy group, or a nitrile group. n represents an integer of 0 or more, and m represents an integer of 2 or more.

8. The organoaluminum compound (C) is In the general formula (1), R ２１ At least one of R is an alkyl group having 1 to 6 carbon atoms, and ２１ an aluminum compound represented by the general formula (1), wherein at least one of the above is an alkoxy group having 1 to 6 carbon atoms; In the general formula (2-1), R ２２ are each independently an alkyl group having 1 to 6 carbon atoms, and an aluminum oxy compound represented by the general formula (2-1), In the general formula (2-2), R ２２ are each independently an alkyl group having 1 to 6 carbon atoms, The method for producing an ethylene polymerization catalyst according to claim 7, wherein the catalyst is at least one selected from the group consisting of:

9. 3. The method for producing an ethylene polymerization catalyst according to claim 1, wherein in the step (2), a ratio of aluminum atoms in the organoaluminum compound (C) to chromium atoms contained in the chromium catalyst (A) is 0.1 to 100 as a molar ratio ([Al] / [Cr]).

10. 3. A method for producing an ethylene polymer, comprising: carrying out ethylene homopolymerization or copolymerization of ethylene and an α-olefin using an ethylene polymerization catalyst obtained by the method for producing an ethylene polymerization catalyst according to claim 1 or 2; and using the ethylene polymerization catalyst in a non-reducing atmosphere without calcining the catalyst.

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