JPH0465846B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a high temperature and high pressure polymerization method for ethylene. At a temperature of 125℃ or higher and a pressure of 200Kg/cm2 ^or higher,
Methods for polymerizing ethylene in the presence of Ziegler type catalysts are known. As the above-mentioned catalyst, a combination of a titanium component, such as a titanium compound supported on a titanium trichloride and a magnesium compound, and an organoaluminum compound has been proposed (for example, Japanese Patent Laid-Open Nos. 49-97087 and 56-18607). , 57
−190009). Since all the titanium components used in the proposed method are solid, they have the following problems. The solid titanium component must be fed to the polymerization reactor maintained at high pressure as a slurry in a medium of appropriate viscosity and specific gravity. However, it is difficult to prepare a uniform slurry of titanium components, and even if a uniform slurry can be prepared, the solid titanium components tend to settle in the transport pipe, and the titanium components cannot be quantitatively transferred to the polymerization reactor. It is extremely difficult to supply. Since the amount of titanium component supplied to the polymerization reactor is not constant, the stability of the polymerization reaction is lost. In particular, if the titanium component is supplied in excess, the polymerization reaction will run out of control, resulting in an extremely dangerous situation. In the high-temperature, high-pressure polymerization of ethylene using a Ziegler-type catalyst, it is desired to develop a liquid titanium component with high catalytic activity. The present applicant proposed a method for polymerizing ethylene that satisfies the above requirements in Japanese Patent Application No. 199969/1982. The proposed method involves high-temperature, high-pressure polymerization of ethylene in the presence of a titanium-containing solution obtained by contacting magnesium 2-ethylhexanoate with a titanium compound in the presence of a hydrocarbon solvent, and a catalyst obtained from an organoaluminum compound. This is the way to do it. The present invention provides a method for polymerizing ethylene that is an improvement on the method proposed above. That is, in the present invention, ethylene or a mixture of ethylene and an α-olefin having 3 or more carbon atoms is heated at a temperature of 125° C. or higher at a temperature of 200 kg/kg in the presence of a catalyst obtained from component [A] and component [B] below. This is an ethylene polymerization method characterized by polymerization under pressure of cm ² or higher. Component [A ^] : Magnesium 2 ^- ethylhexanoate, formula X ¹ Ti (OR ¹ ) ₄ -m (wherein, 20 hydrocarbon groups, m is a number from 0 to 4) and 0.05 to 10 moles of water per mole of the titanium compound, obtained by contacting them in the presence of a hydrocarbon solvent. Titanium-containing solution. Component [B]: Formula R ² nAlX ^2/3 −n (wherein, X ² has the same meaning as X ¹ above, R ²
represents an alkyl group having 1 to 12 carbon atoms or a phenyl group, and n is a number greater than 1 and less than 3. ) is an organoaluminum compound represented by According to the present invention, since all catalyst components are liquid, each component can be quantitatively supplied to the polymerization reactor, and furthermore, ethylene polymer can be obtained in extremely high yield per catalyst used. . Magnesium 2-ethylhexanoate used in the present invention can be prepared, for example, by a reaction known per se as described below. (1) Reaction of dialkylmagnesium or dialkoxymagnesium with 2-ethylhexanoic acid. (2) Reaction between metallic magnesium and 2-ethylhexanoic acid. (3) Reaction of magnesium hydroxide or magnesium oxide with 2-ethylhexanoic acid. Specific examples of titanium compounds include titanium tetrachloride, titanium tetrabromide, methoxytitanium trichloride, ethoxytitanium trichloride, butoxytitanium trichloride, octoxytitanium trichloride, dodecacoxytitanium trichloride, and phenoxytitanium trichloride. , benzoxytitanium trichloride, ethoxytitanium tribromide, ethoxytitanium triiodide, diethoxytitanium dichloride, dibutoxytitanium dichloride, dihexoxytitanium dichloride, triethoxytitanium chloride, tributoxytitanium chloride, trihexoxytitanium chloride, Trioctoxytitanium chloride, tetramethoxytitanium, tetraethoxytitanium, tetrabutoxytitanium, and tetraoctoxytitanium are mentioned. The amount of the titanium compound used is preferably 0.005 to 1 mol, particularly 0.01 to 0.5 mol, per 1 mol of magnesium 2-ethylhexanoate. The amount of water used is 0.05 to 1 mole of titanium compound.
10 moles, preferably 1 to 5 moles. If the amount of water used is less than the lower limit, the polymerization activity of the catalyst obtained will decrease, and even if the amount used is larger than the upper limit, the polymerization activity of the catalyst obtained will not increase further.
Since the organoaluminum compound is simply wasted during the polymerization of ethylene, it is industrially meaningless. Specific examples of hydrocarbon solvents include aliphatic hydrocarbons such as pentane, hexane, and heptane; alicyclic hydrocarbons such as cyclopentane and cyclohexane; aromatic hydrocarbons such as benzene, toluene, and xylene; Examples include halides. The amount of hydrocarbon solvent used is usually 1 to 100 per mole of magnesium 2-ethylhexanoate. There is no particular restriction on the method of bringing magnesium 2-ethylhexanoate, the titanium compound, and water into contact in the presence of a hydrocarbon solvent, and for example, the following method can be employed. (1) A method of adding water and then a titanium compound to a hydrocarbon solvent solution of magnesium 2-ethylhexanoate. (2) A method of adding the above solution and water to a titanium compound. (3) A method of adding water and then a solution of a titanium compound in a hydrocarbon solvent to the above solution. (4) A method of adding a solution of magnesium 2-ethylhexanoate and water to a solution of a titanium compound. Note that when magnesium 2-ethylhexanoate is synthesized by the reaction of magnesium hydroxide or magnesium oxide with 2-ethylhexanoic acid, water is produced as a by-product, so a solution of magnesium 2-ethylhexanoate containing water is mixed with titanium Titanium-containing solutions can also be obtained by contacting with compounds. The contact temperature is usually 0 to 300°C, preferably 10 to 300°C.
It is 200℃. There are no particular restrictions on the contact time, which is usually 5 minutes or more. The titanium-containing solution thus obtained is subjected to a polymerization reaction as it is or diluted with a hydrocarbon solvent if necessary. Specific examples of organoaluminum compounds (component [B]) include diethylaluminum chloride,
Dibutylaluminum chloride, dihexylaluminum chloride, diethylaluminum bromide, diethylaluminum iodide, diphenylaluminum chloride, and dibenzylaluminum chloride. The amount of organoaluminum compound used is usually 1 to 1 per gram atom of titanium in the titanium-containing solution.
It is 1000 moles. In the present invention, component [A] and component [B]
An ethylene homopolymer or an ethylene copolymer is obtained by polymerizing ethylene or a mixture of ethylene and an α-olefin having 3 or more carbon atoms in the presence of a catalyst obtained from . Specific examples of α-olefins having 3 or more carbon atoms include propylene, butene-1,4-methylpentene-1, and octene-1. Polymerization pressure is 200Kg/ ^cm2 or more, preferably 500~
It is 3000Kg/ ^cm2 . The polymerization temperature is 125°C or higher, preferably 150-350°C. The average residence time of the monomer in the polymerization system is 2 to 600 seconds, preferably 10 to 150 seconds.
Seconds. As the polymerization apparatus, a tubular reactor or a tank reactor can be used. The molecular weight of the polyethylene produced can be easily controlled by adding a molecular weight regulator, such as hydrogen, to the polymerization system. Next, Examples and Comparative Examples will be shown. In the following, "polymerization activity" means the production amount (Kg) of ethylene polymer per 1g of titanium in component [A] used in the polymerization reaction, and "MI" means the production amount (Kg) of ethylene polymer per 1g of titanium in component [A] used in the polymerization reaction, and "MI" is the ASTM D
Melt index of ethylene polymer measured at 190°C under a load of 2.16 kg according to 1238. Examples 1 to 3 (1) Preparation of titanium-containing solution (component [A]) Commercially available 2-ethylhexanoic acid was vacuum distilled at 1 mmHg, and the fraction at 76 to 78°C was collected. 5.55 mol of purified 2-ethylhexanoic acid thus obtained was added to Ciel Sol-71 (manufactured by Ciel Chemical Co., Ltd.) 8, and to this solution, a solution 2 of 2.52 mol of di-n-hexylmagnesium in n-heptane was gradually added at 0°C. added.
Thereafter, the temperature of the solution was raised to 90°C and stirred at the same temperature for 1 hour to obtain a colorless and transparent solution. The amount of water listed in Table 1 was added to this solution, and the mixture was thoroughly dispersed using an ultrasonic shaker. After the obtained homogeneous solution was cooled to room temperature, 1.2 of an n-heptane solution containing 0.347 mol of tetra-n-butoxytitanium was added under stirring to obtain a homogeneous solution. This solution was diluted with Ciel Sol 71 (manufactured by Ciel Chemical Co., Ltd.) 19.7 to obtain component [A]. (2) Polymerization In a reaction tube with a total length of about 400 m, 60% by weight of ethylene,
Continuously supplying a monomer consisting of 40% by weight of butene-1 and 0.2% by volume of hydrogen to the monomer,
Ethylene and butene-1 were copolymerized under a pressure of 2000 Kg/cm ² . Ciel Sol 71 solutions (concentration: 1.425 mol/h) of diethylaluminum chloride as the above component [A] and component [B] were added at a rate of 4/hour and 3.5/hour, respectively, into an inlet provided at the inlet of the reaction tube. It was fed continuously from the point. The temperature inside the reaction tube was maintained at 140°C at the inlet and 250°C at the maximum temperature.
The flow rate of the monomer in the reaction tube was 10 m/sec. Cielsol 71 slurry of zinc stearate (concentration: 0.45 mol/hour) was injected as a stopper at a rate of 5.5/hour from an injection point provided at the outlet of the reaction tube. After performing the above continuous operation for 3 hours, ethylene/
A butene-1 copolymer was obtained. The MI, density and polymerization activity of the above copolymers are shown in Table 1. Comparative Example 1 Example 1 was repeated except that no water was used during the preparation of component [A]. The results are shown in Table 1.

TABLE Examples 4 and 5 Example 1 was repeated, except that 0.347 mol of the titanium compound listed in Table 2 was used instead of tetra-n-butoxytitanium. The results are shown in Table 2.

[Table] Examples 6 and 7 The amount of tetra-n-butoxy titanium used was 0.416
Example 1 was repeated except that 0.231 mole (Example 6) or 0.231 mole (Example 7) was changed. The results are shown in Table 3.

[Table] Example 8 (1) Preparation of titanium-containing solution (component [A]) Using Cielsol-71 30 as a solvent, 78 moles of magnesium oxide and 77.1 moles of 2-ethylhexanoic acid purified by distillation were heated at 170°C under a nitrogen atmosphere. under stirring with
The reaction was allowed to proceed for 10 hours. After the reaction, the reaction mixture was filtered through a wire mesh filter with diatomaceous earth to obtain a transparent liquid. The mixture was slowly cooled to 120° C. and stirred at 100 mmHg for 2 hours. The magnesium content in the Cielsol-71 solution of magnesium 2-ethylhexanoate thus obtained was 3.12 wt% as metal.
Moreover, the water content in the obtained magnesium 2-ethylhexanoate solution was 4952 PPM. 1.0 of a solution of Cielsol-71 containing 2.29 moles of tetra-n-butoxytitanium was added to 25 of the Cielsol-71 solution of magnesium 2-ethylhexanoate obtained above under a nitrogen atmosphere at room temperature to obtain a homogeneous solution. Add Cielsol 71 to the resulting titanium-containing solution.
52 was added and diluted to obtain component [A]. (2) Polymerization Except that the feed rates of component [A] and component [B] above were changed to 5.0/hour and 5.2/hour, respectively, and the feed rate of Cielsol 71 slurry of zinc stearate was changed to 8.2/hour. Ethylene and butene-1 were copolymerized in the same manner as in Example 1. An ethylene/butene-1 copolymer with an MI of 4.9 g/10 min and a density of 0.922 g/cm ² was obtained with a polymerization activity of 810.

[Brief explanation of drawings]

FIG. 1 shows a flowchart of the manufacturing process of the catalyst of the present invention.

Claims (1)

[Claims] 1. Ethylene or ethylene and α- having 3 or more carbon atoms
Polymerization of ethylene characterized by polymerizing a mixture with olefin at a temperature of 125° C. or higher and a pressure of 200 kg/cm ² or higher in the presence of a catalyst obtained from the following component [A] and component [B]. legal. Component [A ^] : Magnesium 2 ^- ethylhexanoate, formula X ¹ Ti (OR ¹ ) ₄ -m (wherein, 20 hydrocarbon groups, m is a number from 0 to 4) and 0.05 to 10 moles of water per mole of the titanium compound, obtained by contacting them in the presence of a hydrocarbon solvent. Titanium-containing solution. Component [B]: Formula R ² nAlX ^2/3 −n (wherein, X ² has the same meaning as X ¹ above, R ²
represents an alkyl group having 1 to 12 carbon atoms or a phenyl group, and n is a number greater than 1 and less than 3. ) is an organoaluminum compound represented by