JPH0549685B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a process for polymerizing propylene. In particular, it relates to a method using an activated titanium catalyst obtained by a specific method. Prior Art Since the method of polymerizing propylene using an activated titanium catalyst obtained by supporting titanium chloride on a metal halide, particularly magnesium chloride, and a catalyst consisting of an organoaluminum was proposed in Japanese Patent Publication No. 12105/1989, many studies have been made. Improved processes have been proposed, resulting in significantly higher yields per catalyst and stereoregularity of the polypropylene obtained. However, both the stereoregularity and the yield per catalyst of the resulting polypropylene are insufficient for applications such as films, and the polypropylene cannot be used without thoroughly removing catalyst residues and atactic polypropylene, and further improvements are needed. is desired. Problems to be Solved by the Invention The present inventors have conducted extensive studies on methods for solving the above problems, and as a result of using an activated titanium catalyst that has undergone a specific treatment, the yield per catalyst and the stereoregularity of the obtained polypropylene can be improved. The present invention was completed based on the discovery that the properties were significantly improved. An object of the present invention is to provide a method for producing highly stereoregular polypropylene with good yield per catalyst. Means for Solving the Problems The present invention provides a method for polymerizing propylene using an activated titanium catalyst obtained by supporting titanium tetrachloride on magnesium chloride and a catalyst consisting of an organoaluminium compound, in which magnesium chloride is used as an active titanium catalyst. The present invention relates to a method for polymerizing propylene, which is characterized in that titanium tetrachloride is supported on a propylene and then dispersed in an inert hydrocarbon medium and irradiated with visible and/or ultraviolet light. The present invention is characterized by an activated titanium catalyst obtained by supporting titanium tetrachloride on magnesium chloride. That is, titanium tetrachloride is supported on magnesium chloride and then dispersed in an inert hydrocarbon medium and irradiated with visible and/or ultraviolet light. There are no particular limitations on the method for producing an active titanium catalyst obtained by supporting titanium tetrachloride on magnesium chloride used for light irradiation, and known methods can be applied, such as a method of co-pulverizing magnesium chloride and titanium tetrachloride, and fine particles. A method of contacting magnesium chloride with liquid titanium chloride such as titanium tetrachloride, and a method of obtaining fine particulate magnesium chloride include grinding magnesium chloride or co-pulverizing magnesium chloride and an oxygen-containing organic compound. A method is already known in which fine particles containing magnesium chloride as a main component are obtained by solubilizing magnesium chloride in a hydrocarbon medium by reacting or complexing it with an oxygen-containing organic compound, and then insolubilizing it with a metal halide. The present invention can be used with any activated titanium catalyst obtained by any of the above methods, but preferably,
Halogen substituted products of aliphatic aromatic hydrocarbons such as methylene dichloride, ethylene dichloride, propane chloride, chlorobenzene, benzotrichloride, etc., i.e., those treated with halogenated hydrocarbons, i.e., added during co-pulverization or in contact with titanium chloride It is more preferable to use a material that has been subjected to a contact treatment at the time of or before irradiation with light, and a material that has been subjected to a contact treatment at the time of or prior to light irradiation. Examples of the oxygen-containing organic compounds shown above include alcohols, ethers, esters, orthoesters, ketos, aldehydes, amides, etc. Among them, ethers, esters, and orthoesters are preferably used. It is also possible to use alcohols in combination. Specific compounds include dialkyl ethers such as diethyl ether, dipropyl ether, dibutyl ether, and diamyl ether, diphenyl ether and its aromatic ring-substituted ethers, dibenzyl ether and its aromatic ring-substituted ethers, ethyl acetate, vinyl acetate, Alkyl esters of benzoic acid such as methyl acrylate, ethyl acrylate, methyl methacrylate, ethyl methacrylate, methyl benzoate, ethyl benzoate, propyl benzoate and their aromatic ring substitutes, phthalic acid, isophthalic acid, terephthane Alkyl diesters of acids such as methyl, ethyl, propyl, methyl orthoformate, ethyl orthoformate, methyl orthoacetate, ethyl orthoacetate, propyl orthoacetate, butyl orthoacetate, methyl orthopropionate, ethyl orthopropionate, propyl orthopropionate , butyl orthopropionate, methyl orthobenzoate,
Examples include ethyl orthobenzoate, propyl orthobenzoate, and aromatic ring-substituted orthoesters thereof. Alkoxysilicon such as tetraethoxysilane, triethoxyphenylsilane, diethyldiethoxysilane and the like can also be used. In addition, examples of halogenated hydrocarbon compounds include methylene dichloride, chloroform, carbon tetrachloride, methylene dibromide, methane tribromide, carbon tetrabromide, ethylene dichloride, ethane trichloride, ethane tetrachloride, and dibromide. Halogen-substituted aliphatic hydrocarbons such as ethane, propane dichloride, propane trichloride, chlorobenzene, dichlorobenzene, trichlorobenzene, α-chlorotoluene,
Examples include α,α-dichlorotoluene and α,α,α-trichlorotoluene. In the present invention, the activated titanium catalyst obtained by the above method is irradiated with light while being dispersed in an inert hydrocarbon medium. As the inert hydrocarbon medium, the above-mentioned halogenated hydrocarbons, hydrocarbon compounds such as hexane, heptane, octane, decane, benzene, toluene, etc. are used, and they are contacted with liquid titanium halide to form an activated titanium catalyst. When obtaining , it is common to remove free titanium chloride by washing with an inert hydrocarbon after contact treatment, and after washing, the activated titanium catalyst obtained in a slurry state is directly irradiated with light. is simple. For irradiation with ultraviolet and/or visible light, any light source can be used and sunlight can be used, but from the viewpoint of stability and intensity of the light source, medium-pressure or high-pressure mercury lamps or xenon lamps are recommended. By using a lamp. A catalyst in which titanium chloride is supported on magnesium chloride dispersed in an inert hydrocarbon medium to be irradiated hardly transmits light and reactions caused by light irradiation occur only on the surface facing the light source. It is more effective to mix by stirring at the same time. The time used for light irradiation varies depending on the intensity of the light source and the stirring state of the dispersion liquid and cannot be specified, but for example, it is possible to use a dispersion liquid in which 10 g of a catalyst of titanium tetrachloride supported on magnesium chloride is dispersed in 100 ml of an inert hydrocarbon medium.
When irradiating with light using a 300W high-pressure mercury lamp, it is sufficient to irradiate for about 30 minutes to 10 hours. In the present invention, the organoaluminum compounds used in combination during polymerization include trialkylaluminum such as triethylaluminum, tripropylaluminum, tributylaluminum, tripentylaluminum, and trihexylaluminum, diethylaluminum chloride, dipropylaluminum chloride, dibutylaluminum chloride, and dipentylaluminum. Dialkyl aluminum chloride such as aluminum chloride, dialkyl aluminum bromide with bromine or iodine in place of chlorine, dialkyl aluminum iodide, and ethyl aluminum sesquichloride or ethyl aluminum dichloride can also be used, but trialkyl aluminum is preferable. , and dialkyl aluminum chloride. In the present invention, it is effective to use a stereoregularity improver such as ether, ester, amide, orthoester, alkoxy silicon, etc. in combination during polymerization to obtain a polypropylene with higher stereoregularity. In the present invention, the polymerization of propylene can be applied not only to propylene alone but also to copolymerization with other olefins such as ethylene, butene-1, hexene-1, etc. The polymerization reaction can be carried out in an inert medium, by a bulk polymerization method in which an inert medium is not substantially present, or by a gas phase polymerization method under conditions of normal temperature to 90°C and normal pressure to 50 kg/cm ² -gauge. It will be done. Effects By applying the method of the present invention, polypropylene with high stereoregularity can be obtained in high yield per catalyst, which is industrially valuable. Examples The present invention will be explained below with reference to Examples. Example 1, Comparative Example 2 A A vibratory mill equipped with two grinding pots each having an internal volume of 900 ml each containing 1.2 kg of steel balls with a diameter of 12 mm is prepared. Add 30 g of magnesium chloride (containing 0.2 wt% water), 4 ml of ethyl orthoacetate, and 6 ml of 1,2-dichloroethane to this pot in a nitrogen atmosphere.
Co-milled for 40 hours. B 20 g of the above co-pulverized product was put into a 500 ml round bottom flask, 200 ml of titanium tetrachloride was added thereto, and contact treatment was carried out at 80° C. with stirring. Then let it stand and remove the supernatant.
The operation of adding 200 ml of n-heptane, stirring, standing still, and removing the supernatant was repeated 9 times to obtain a titanium catalyst, and 200 ml of n-heptane was added to form a slurry. C Spread 200ml of the above titanium catalyst slurry almost evenly.
Divide into two Pyrex round bottom flasks and use one for polymerization as is (Comparative Example 1).
(trade name) for one hour at a position 20 cm from the light source (Example 1). D: 30 mg of the above titanium catalyst, 0.128 ml of diethylaluminum chloride, 0.05 ml of methyl p-toluate under a nitrogen stream in an autoclave with an internal volume of 5.
ml, triethylaluminum 0.08ml to 50ml n
-Add the mixture in hexane, then add 1.5Kg of liquid propylene and 1.25Nl of hydrogen, heat to 75℃ and polymerize at 75℃ for 2 hours, then purge unreacted propylene and take out the polypropylene powder at 60℃ and 70mHg. The product was dried for 10 hours, weighed, and the yield per active titanium catalyst was calculated, and extracted with boiling n-heptane using a Tetralin solution at 135°C for 5 hours using the intrinsic viscosity and a Soxhlet extractor.
Boiling n-heptane extraction residual rate (powder weight after extraction/powder weight before extraction x 100%)
(hereinafter abbreviated as II) was calculated. The results are shown in the table. Example 2 The same procedure as in Example 1 was carried out except that the light irradiation was carried out in a hard glass flask (which does not transmit light of 310 nm or less) and the irradiation time was 4 hours. The results are shown in the table. Example 3 The same procedure as in Example 1 was conducted except that light irradiation was carried out by cutting out light with a wavelength of less than 365 nm through a UV35 cut filter (manufactured by Toshiba Corporation) and the irradiation time was 10 hours. The results are shown in the table. Examples 4 to 8, Comparative Examples 2 to 6 The compounds shown in the table were added during co-pulverization, and Example 4
In Comparative Example 2, Example 1 and Comparative Example 1 were washed with toluene containing 20 vol% of ethylene dichloride.
The results are shown in the table. 【table】

[Brief explanation of drawings]

FIG. 1 is a flow diagram to aid understanding of the present invention.

Claims (1)

[Claims] 1 In a method of polymerizing propylene using an active titanium catalyst obtained by supporting titanium tetrachloride on magnesium chloride and a catalyst consisting of an organoaluminum compound, titanium tetrachloride is supported on magnesium chloride as an active titanium catalyst, and then inert carbonization is carried out. A method for polymerizing propylene, which comprises using propylene obtained by irradiating visible and/or ultraviolet light while being dispersed in a hydrogen compound medium.