JPH0117489B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [] BACKGROUND TECHNICAL FIELD OF THE INVENTION The present invention relates to a catalyst for olefin polymerization using a novel titanium compound. Stereospecific polymerization of olefins, especially α-olefins, is usually produced using a series of catalyst systems called Ziegler catalysts or complex catalysts. That is, as essential components of the catalyst, a multi-element compound containing a compound in a valence state lower than the highest valence of a transition metal element in Groups ~ of the Periodic Table, and a hydride compound or an organometallic compound of a metal in Groups ~ of the Periodic Table. Highly active stereoregular polymers can be obtained for the first time using composite catalysts. Regarding the active center theory of such multi-component composite catalysts, there are various interpretations, such as theories centering on transition metals and theories centering on typical metals, but the fact is that unless both components are used together, industrial However, it has not been possible to produce catalysts with high activity and high stereospecificity to a meaningful extent. Prior Art However, in recent years, in the process of researching the polymerization mechanism of olefins using Ziegler catalysts, the present inventors have discovered that catalysts obtained by a special preparation method, even if they are composed only of transition metal components. They discovered that they have high activity for the stereospecific polymerization of olefins, especially α-olefins, and filed two patent applications for this invention. That is, the invention of JP-A No. 56-5805 uses a zeolite catalyst in which the exchangeable cation of the zeolite is titanium or vanadium ion in a valence state lower than the highest valence, thereby achieving high polymerization of ethylene and propylene. The aim is to carry out highly stereospecific polymerization of α-olefins with high activity. On the other hand, the invention of JP-A No. 56-5806 uses a titanium or vanadium halide in a valence state lower than the highest valence bonded to a silica, alumina, or silica/alumina support via an oxygen atom as a catalyst, and also uses an olefin as a catalyst. (stereospecific) polymerization. Although both of these catalysts contain only transition metal compound components, this can be said to be the first example in which a high polymer yield per transition metal could be obtained. [] Summary of the Invention The present inventors believed that the performance of these catalysts was still insufficient, and as a result of further research, they developed a catalyst system that does not require an organometallic compound component and has even further improved performance. was successfully developed. That is, the catalyst for olefin polymerization according to the present invention has the general formula () R ₃ M-O-TiX ₂ () (wherein R represents hydrogen or a hydrocarbon residue, M represents silicon, and X represents a halogen atom. ). Effects The catalyst of the present invention has superior stereospecificity compared to the one-component catalysts of the two inventions. In addition, particularly in the case of a supported catalyst in which the catalyst is further supported on a carrier, stereospecificity and polymerization activity are improved. Although the reason for this is not necessarily clear, the cause of the high activity is presumed to be as follows. (b) In the case of the above-mentioned zeolite catalyst, the outer shell of the zeolite has pores with a number and size determined by the type of zeolite relative to the transition metal in the center, and polymerization occurs through these pores when the monomer converts to the transition metal. It is thought that the process proceeds by approaching the transition metal, but since the cross-sectional area of this pore is only slightly larger than the size of the monomer, the speed at which the monomer approaches the transition metal is slow, and the polymerization activity cannot be sufficiently increased. It seems to be. (b) In the case of the silica (or alumina, or silica/alumina) supported catalyst, the transition metal compound is supported via the hydroxyl groups distributed over the entire surface area of the silica, but within the many pores that make up the silica surface. It is thought that the transition metal supported on the surface with a small pore size cannot sufficiently function as an active center of a highly active catalyst because the approach of the monomer to the transition metal is slow, as in the case of the zeolite catalyst described above. However, in the catalyst of the present invention, since the transition metal has a bulky substituent as shown in the general formula (), the compound cannot enter into the pores with a small cross-sectional area on the surface of the carrier. ,
Therefore, it is supported only in pores with relatively large pores that allow easy access to the monomer. Therefore, it is thought that the proportion of supported transition metals that can be used as polymerization centers is increased, resulting in an increase in polymerization activity. Furthermore, in the one-component catalysts according to the two inventions, each transition metal was supported on the carrier by a specific chemical bond. For this reason, carriers could only be selected from a very limited range. However, in the catalyst of the present invention, the carrier has no chemical bond with the compound of general formula (); in other words, it supports the latter by physical adsorption. Therefore, there is a high degree of freedom in selecting the body. Therefore, in addition to the activity and stereospecificity,
It is possible to select a carrier that can maximize various properties such as particle size distribution and bulk specific gravity. [] Detailed description of the invention 1 Catalyst compound R ₃ M-O-TiX ₂ The olefin polymerization catalyst of the present invention has the general formula R ₃ M
-O-TiX ₂ (wherein R represents a hydrogen atom or a hydrocarbon residue, M represents silicon, and X represents a halogen atom), which is represented by the general formula R ₃ M-OH. It can be understood as a condensation compound of the compound and _TiX3 . In fact, it can be obtained by condensing both, but a more efficient preparation method is to react R ₃ M-OH with TiX ₄ and pre-mix TiX ₃ with the compound represented by the formula R ₃ M-O-TiX ₃ . In this method, one halogen atom is removed using a suitable reducing agent to obtain the desired compound. Although there are no particular restrictions on the reducing agent used here, organometallic compounds such as aluminum and magnesium are usually used. M in the above general formula is silicon. Further, the substituent R is hydrogen or a hydrocarbon residue having 1 to 12 carbon atoms, preferably about 1 to 7 carbon atoms, and a plurality of R's in one compound may be the same or different types. X represents a halogen atom, specifically selected from fluorine, chlorine, bromine, and iodine atoms. Most preferred is chlorine. Specifically, ( _CH3 ) _{3SiOTiCl2 ,}
(C ₂ H ₅ ) ₃ SiOTiCl ₂ , (C ₆ H ₅ ) ₃ SiOTiCl ₂ ,
_{( CH3 ) 2C6H5SiOTiCl2 , CH3}
(C ₆ H ₅ ) ₂ SiOTiCl ₂ , (C ₂ H ₅ ) ₂ C ₆ H ₅ SiOTiCl ₂ ,
(o-CH ₃ C ₆ H ₅ ) ₃ SiOTiCl ₂ , (m-
CH ₃ C ₆ H ₅ ) ₃ SiOTiCl ₂ , (p-
CH ₃ C ₆ H ₅ ) ₃ SiOTiCl ₂ , (C ₆ H ₅ CH ₂ ) ₃ SiOTiCl ₂ ,
(α−C ₁₀ H ₇ ) ₃ SiOTiCl ₂ , (C ₆ H ₅ ) ₃ SiOTiBr ₂ ,
(C ₆ H ₅ ) ₃ SiOTiI ₂ is mentioned. Support Although the titanium compound has olefin polymerization ability as it is, it exhibits even higher catalytic performance by supporting it on a support. The carrier used for this purpose is a powdery solid with an appropriate particle size, and may be selected from any solid substance as long as it does not have a functional group that significantly reacts with the titanium compound being supported. . Solid substances that can normally be used for this purpose include inorganic oxides and chlorides of various metals,
Examples include hydroxides, inorganic acid salts, and organic polymer particles. Specifically, silica, alumina, silica/alumina, magnesia, zinc oxide, titania, zirconia, chromia, magnesium chloride, calcium chloride, magnesium hydroxychloride (Mg(OH)Cl), magnesium hydroxide, calcium hydroxide, carbonate. Examples include inorganic carriers such as calcium, magnesium sulfate, hydrotalcite, kaolin, halloysite, and talc, and polymeric powder carriers such as polypropylene powder and polyethylene powder. Among these carriers, silica, alumina, silica-alumina, magnesia, magnesium chloride, and magnesium hydroxychloride are preferred. These carriers preferably have a high specific surface area and are highly amorphous. Further, it is preferable that the amount of adsorbed water and hydroxyl groups on the surface be as small as possible, and for this purpose, it is preferable to use the material after baking it or pre-treating it with an organoaluminium, organomagnesium compound, or the like. Supporting method As already mentioned, the compound represented by the general formula () can also be prepared by the condensation reaction of the hydroxide represented by the general formula R ₃ M-OH and TiX ₃ , but the ease of reaction From the point of view of the general formula
R ₃ M−O−TiX ₃ is prepared in advance from R ₃ M−OH and TiX ₄ .
It is preferable to prepare and then reduce with an organometallic compound or the like to obtain a compound of general formula (). When using the former method, in order to support the compound () on the carrier, it is necessary to use mechanical contact means such as co-pulverizing both in a mill, since () is usually a solid. On the other hand, when taking the latter method, the carrier and
A compound of R ₃ M-O-TiX ₃ is dispersed in an inert medium, preferably a hydrocarbon such as hexane or heptane or a halohydrocarbon such as 1,2-dichloroethane, and a suitable reducing agent is added thereto. In addition
_R3M -O- _TiX3 can be reduced to the compound () and simultaneously supported on the carrier. In this case, it is necessary to thoroughly wash the solid catalyst after the supporting operation with the inert medium to remove by-products accompanying the reduction reaction. Amount Ratio The appropriate range of supported amount varies depending on the type of carrier and the type of compound (), but it is preferable that the proportion of titanium atoms in the final catalyst is 0.1 to 10% by weight (preferably 0.3 to 7% by weight, more preferably 0.3 to 7% by weight). is 0.5~5
It is best to choose between weight percentages. This is because outside this range, the activity and/or high body specificity will be impaired. Activity Improver Although the above catalyst alone has olefin polymerization ability, the activity can be improved by further adding other catalyst components. Specifically, the above object can be achieved by using the same organoaluminum compound used in the Ziegler type catalyst. As an organoaluminum compound, the general formula
An organoaluminum compound represented by AlR _o X _3-o is used. Here R is hydrogen, carbon number 1
~20 hydrocarbon residues, especially alkyl, aralkyl or aryl groups, X is halogen, especially chlorine or bromine, and n is a number in the range satisfying 0<n≦3. Specifically, (a) trialkyl aluminum such as trimethylaluminum, triethylaluminum, triisobutylaluminum, trioctylaluminum, and tridecylaluminum, (b) diethylaluminum monochloride, diisobutylaluminum monochloride, ethylaluminum sesquichloride, ethyl Examples include dialkyl aluminum halides such as aluminum dichloride, and alkyl aluminum hydrides such as (iii) diisobutyl aluminum hydride. The amount of organoaluminum compound used is 0.01 to 200 in weight ratio to the compound (), preferably
It is between 0.03 and 100. 2 Olefin Polymerization The olefin polymerization method using this catalyst is essentially the same as that using a normal Ziegler type catalyst, except that the catalyst is as described above. (1) Olefin Olefin polymerized with the catalyst system of the present invention has the general formula R-CH=CH ₂ (where R is a hydrogen atom or a hydrocarbon residue having 1 to 10 carbon atoms, even if it has a substituent. It is an α-olefin represented by Specifically, for example, ethylene, propylene, butene-1, pentene-1
There are olefins such as 1,4-methyl-pentene-1, 3-methylbutene-1. Preference is given to ethylene or propylene, particularly preferably propylene. It is also possible to use mixtures of α-olefins. For example, in the case of propylene polymerization, it is possible to copolymerize propylene with up to 20% by weight of the other α-olefins mentioned above. It is also possible to carry out copolymerization with copolymerizable monomers other than the above-mentioned α-olefins (eg, vinyl acetate, diolefins). (2) Polymerization It goes without saying that polymerization can be applied to ordinary slurry polymerization or solution polymerization, but it can also be applied to solvent-free polymerization in which substantially no solvent is used.
Furthermore, it can be applied to continuous polymerization, batch polymerization, and prepolymerization. Polymerization solvents include hexane, heptane,
Saturated aliphatic, aromatic, such as cyclohexane, benzene, toluene, methylcyclohexane,
Alternatively, alicyclic hydrocarbons may be used alone or in mixtures. The polymerization temperature is from room temperature to 200°C, preferably from 50 to 180°C. The polymerization pressure can be any pressure sufficient to initiate the polymerization of the monomers into a high polymer, generally between normal pressure and 500 Kg/cm ² , preferably between 4 and 100 Kg/cm ² . Implemented. Furthermore, hydrogen can be added as a molecular weight regulator during polymerization. Example 1 Preparation of catalyst Equimolar moles of TiCl ₄ and (C ₆ H ₅ ) ₃ SiOH in toluene
(manufactured by Aldrich Co. Ltd.) was reacted at 90° C. for 20 hours with stirring. The reaction product was recovered by removing toluene under vacuum at room temperature. Next, 2 g of the above product and γ-alumina (BET
Specific surface area 140m ² / determined by N ₂ gas adsorption method
g) 5 g was added to 10 ml of toluene and stirred thoroughly, followed by vacuum treatment at 90°C for 3 hours to remove toluene. The obtained product was reduced by treatment with 10 ml of a heptane solution containing diethylaluminium (DEAC) at a concentration of 0.5 mol/at room temperature for 20 hours, washed with heptane, and further vacuum-dried at room temperature for 3 hours to obtain the final catalyst. And so. According to infrared (IR) absorption spectrum measurements,
In the raw material (C ₆ H ₅ ) ₃ SiOH, strong absorption was observed at 3590 cm ^-1 due to the stretching vibration of Si-OH.
In the reaction product with TiCl ₄ , this absorption disappears, and instead a broad absorption attributed to the Ti-O-Si bond appears.
It appeared at 920cm ^-1 . The above product (considered to be (C ₆ H ₅ ) ₃ Si-O-TiCl ₃ ) and this product supported on γ-alumina were placed in a Pyrex glass tube with a diameter of 3 mm, and the JEOL JES-PE-IX The ESR absorption spectrum was examined using an ESR spectrometer at -196°C and a field modulation of 100×10 ³ C/S, but no absorption was observed. However, the final catalyst obtained by treating this supported product with DEAC showed absorption at a g value of 1.942. This signal is
Although it is very similar to the ESR signal of co-pulverized TiCl ₃ and γ-alumina as described in K. Soga et al., Polym. Bull., 2 , 817 (1980),
It is clearly different from the signal shown by Ti()-R (where R is an alkyl group) and Ti()-H described in Yu. Yermakov, Adv. Catal., 24 , 173 (1976). It was hot. The amount of Ti atoms supported in the final catalyst was determined by atomic absorption spectroscopy. Propylene polymerization 100ml internal volume with magnetic stirrer
5 ml of heptane, about 0.3 g of the above catalyst, and 0.3 mole of propylene were placed in a stainless steel reactor of 65
Propylene polymerization was carried out for 15 minutes at °C.
Polymerization was stopped by adding the reaction product to a large amount of dilute hydrochloric acid in methanol solution. The resulting polymer was completely dissolved in hot O-dichlorobenzene, precipitated in a large amount of methanol, and then vacuum-dried at room temperature and recovered. Stereoregularity of polymers (II)
JPLuongo, J.Appl.Polym.Sci., 3 , 302
(1960) by IR absorption spectroscopy. The results are shown in Table 1. Example 2 Using a catalyst prepared under the same conditions as in Example 1, propylene polymerization was carried out under the same conditions as in Example 1 except that 2.50 mmol of DEAC was added during polymerization. The results are shown in Table 1. Comparative Example 1 Propylene polymerization was carried out under the same conditions as in Example 1 using a catalyst prepared under the same conditions as in Example 1 except that the reduction treatment with a heptane solution of DEAC was not performed. The results are shown in Table 1. Example 3 Silica (specific surface area 270
Propylene polymerization was carried out under the same conditions as in Example 1 using a catalyst prepared under the same conditions as in Example 1 except that m ² /g) was used. The results are shown in Table 1. Example 4 Using a catalyst prepared under the same conditions as in Example 3, propylene polymerization was carried out under the same conditions as in Example 3 except that 2.50 mmol of DEAC was added during polymerization. The results are shown in Table 1. Example 5 Propylene polymerization was carried out under the same conditions as in Example 1 using a catalyst prepared under the same conditions as in Example 1 except that magnesium chloride (specific surface area: 43 m ² /g) was used instead of γ-alumina. I did it. The results are shown in Table 1. Example 6 Using a catalyst prepared under the same conditions as in Example 5, propylene polymerization was carried out under the same conditions as in Example 5 except that 2.50 mmol of DEAC was added during polymerization. The results are shown in Table 1. Example 7 Propylene polymerization was carried out under the same conditions as in Example 1 using a catalyst prepared under the same conditions as in Example 1 except that magnesium oxide (specific surface area: 23 m ² /g) was used instead of γ-alumina. I did it. The results are shown in Table 1. Example 8 Using a catalyst prepared under the same conditions as in Example 7, propylene polymerization was carried out under the same conditions as in Example 7 except that 2.50 mmol of DEAC was added during polymerization. The results are shown in Table 1. Example 9 Example 1 was carried out using a catalyst prepared under the same conditions as in Example 1 except that magnesium hydroxychloride (Mg(OH)Cl; specific surface area: 8.4 m ² /g) was used instead of γ-alumina. Propylene polymerization was carried out under the same conditions. The results are shown in Table 1. Example 10 Using a catalyst prepared under the same conditions as in Example 9, propylene polymerization was carried out under the same conditions as in Example 9 except that 2.50 mmol of DEAC was added during polymerization. The results are shown in Table 1. Example 11 Propylene polymerization was carried out under the same conditions as in Example 1, except that a reaction product of TiCl ₄ and (C ₆ H ₅ ) ₃ SiOH reduced with DEAC was used as a catalyst without using a carrier. Summer. The results are shown in Table 1. Reference Example 1 The catalyst prepared in Example 9 was treated with carbon dioxide at 20 atmospheres at room temperature for 17 hours, and the catalyst was used as a catalyst.
Propylene polymerization was carried out under the same conditions as in Example 9. The results are shown in Table 1. [This reference example is an experiment to prove that the catalyst of the present invention is a monometallic catalyst in the true sense. That is, the catalyst of Example 9 (which _applies essentially to all other examples) uses DEAC to reduce the reaction product of _TiCl4 , ( _C6H5 ) _3SiOH , and _TiCl4 . This process includes the process of
Ti−C ₂ H ₅ (C ₂ H ₅ group is DEAC This proves that the bonds (derived from the above) do not essentially contribute to the expression of polymerization activity. This means that even if the catalyst of Example 9 had a Ti-C ₂ H ₅ bond, if carbon dioxide was applied to it, It is based on the fact that the reaction occurs quantitatively and the substance changes into a substance that is inert to the polymerization reaction. *: V. Zucchinni et al., J. Organometal
Chem., 26 , 357 (1971)] Reference Example 2 Propylene polymerization was carried out under the same conditions as in Example 1, except that 0.032 g of TiCl ₃ (AA type) and 0.5 mmol of triethylaluminum (TEA) were used as a known catalyst system. I did it. The results are shown in Table 1. 【table】

[Brief explanation of drawings]

FIG. 1 is intended to assist in understanding the technical content of the present invention regarding Ziegler catalysts.

Claims (1)

[Claims] 1 Represented by the general formula R ₃ M-O-TiX ₂ (wherein R represents a hydrogen atom or a hydrocarbon residue, M represents a silicon atom, and X represents a halogen atom) Catalyst for olefin polymerization.