JPS6084307A - Ethylene polymerization method - Google Patents

Abstract

PURPOSE:To deactive a catalyst in good efficiency, by adding a deactivator selected from metaboric acid, boron oxide and basic zinc carbonate to the reaction mixture in the high-temperature high-pressure polymerization of ethylene in the presence of a Ziegler catalyst. CONSTITUTION:Ethylene or a mixture of ethylene with 3C or higher alpha-olefins (e.g., propylene) is polymerized at a pressure >= 200kg/cm<2> and a temperature >=125 deg.C in the presence of a Ziegler catalyst obtained from a transition metal derivative (e.g., titanium trihalide) and an organoaluminum compound (e.g., triethylaluminum). The catalyst in the resulting polymerization mixture is deactivated by adding thereto a deactivator comprising a compound selected from among metaboric acid, boron oxide and basic zinc carbonate. No inhibition of the polymerization reaction of ethylene occurs because the deactivator does not contaminate the ethylene recirculated from the separator to the polymerization vessel.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a process for polymerizing ethylene. In particular, the present invention
This invention relates to a method for inactivating a catalyst in the high-temperature, high-pressure polymerization of ethylene using a Ziegler-type catalyst by adding a novel deactivator to the polymerization reaction mixture.

A method is known in which ethylene is polymerized at high temperature and pressure in the presence of a Ziegler type catalyst obtained from a titanium compound and an organoaluminum compound. For example, JP-A-46-56
No. 40 and Japanese Patent Publication No. 48-6183 describe a method of polymerizing ethylene at high temperature and high pressure in the presence of a catalyst obtained from a titanium halide and an organoaluminum compound. Also, JP-A-52-101485.

No. 56-18607 discloses a method of polymerizing ethylene at high temperature and high pressure in the presence of a catalyst obtained from a titanium compound supported on a magnesium compound and an organoaluminum compound.

In industrial high-temperature, high-pressure polymerization of ethylene.

Polymerizing ethylene using a pre-type reactor or a seed-type reactor,
A process is then adopted in which the polymerization reaction mixture is introduced into a separator maintained at a lower pressure than the reactor, and unreacted ethylene is separated from the produced polymer and recycled to the reactor. When the above-mentioned known high-temperature, high-pressure polymerization method for ethylene is carried out industrially, a catalyst still remaining active is brought into one separator, resulting in the production of unintended polymer in the separator.

Furthermore, in some cases, the above-mentioned catalyst is entrained in the circulating ethylene, causing a problem in that the ethylene polymerizes in the circulating line and blocks the line.

Therefore, in the high-temperature, high-pressure polymerization of ethylene using a Ziegler type catalyst, it is extremely important to deactivate the catalyst in the duplex polymerization reaction mixture at the end of the duplex polymerization reaction. Regarding the method of inactivating the Ziegler type catalyst used in the high-temperature and high-pressure polymerization of ethylene, Japanese Patent Application Laid-Open No. 51-11
The method described in Japanese Patent No. 1'282 is only proposed. According to the method described in the above publication, the Ziegler type catalyst in the single polymerization reaction mixture is deactivated by adding an alkali metal salt or alkaline earth metal salt of a fatty acid, typified by calcium stearate, as a deactivator at the end of the single polymerization reaction. Inactivated.

The present invention provides ethylene or ethylene and α-
The mixture with olefins is heated to 2ooK in the presence of a catalyst obtained from a transition metal derivative and an organoaluminum compound.
As a deactivating agent when polymerizing at a pressure of r/- or more and a temperature of 125° C. or more and adding a deactivating agent to the polymerization reaction mixture to deactivate the catalyst.

This is an ethylene polymerization method characterized by using a compound selected from the group consisting of (a) metaboric acid, (b) boron oxide, and (c) basic zinc carbonate.

Since the deactivator used in the present invention efficiently deactivates the catalyst in the polymerization reaction mixture, it is possible to prevent undesirable ethylene polymerization after the above-mentioned polymerization reaction step. Furthermore, since the deactivating agent used in the present invention does not mix with the ethylene that is circulated from the separator to the polymerization reactor, it does not inhibit the polymerization reaction of ethylene.

The transition metal derivative in the present invention includes halogen-containing compounds of titanium, vanadium, zirconium, and chromium. Among these, halogen-containing titanium compounds are preferably used. Specific examples of halogen-containing titanium compounds include titanium trihalides, solid solutions of titanium trihalides and aluminum aluminum, and supported titanium compounds containing magnesium, halogens, and titanium as essential components. can be mentioned. In addition to the above-mentioned essential components, this supported titanium compound may also contain halogenides, oxides, and alkoxides of calcium, aluminum, silicon, tin, zinc, etc., and may further contain electron donors 1
For example, carboxylic acid esters.

It can also contain ethers, ketones, and amines. The compatible titanium compound can be prepared by a method known per se. For example, a method of co-pulverizing magnesium chloride with titanium chloride in the presence or absence of an electron donor, an organomagnesium compound and an alkylaluminum rhamnolide, an alkoxyaluminum halide, an alkylsilane halide, or an alkoxysilaninohydride Method 9 of reacting the reaction product with titanium halide with titanium halide 9 JP-A-5B'-ss 405, JP-A No. 57-83510, JP-A No. 57-115408, JP-A No. 57 filed by the present applicant -141408 Publication, 57-1451
No. 05, No. 58-2605.

Japanese Unexamined Patent Publication No. 58-5230.8, No. 58-59206
It can be prepared according to the method described in the publication.

As an organoaluminum compound.

Formula RmAtX3-m (In the formula, R1 represents an alkyl group having 1 to 8 carbon atoms.

X represents a halogen atom, and 9m is 1.5-3. ) are preferably used. Specific examples include triethylaluminum, tributylaluminum, and trioctylaluminum.

Diethylaluminum chloride, dibutylaluminum chloride, diethylaluminum chloride, diethylaluminum bromide, diethylaluminum iodite, ethylaluminum sesquichloride, butylaluminum sesquichloride, hexylaluminum sesquichloride, ethylaluminum sesquibromide.

Ethylaluminum sesquiodite is mentioned. Among these, 9 from the point of increasing polymerization activity.

Dialkyl aluminum halides are preferably used.

The amount of the organoaluminum compound used is usually 1 to 1000 mol per gram atom of titanium in the titanium compound.

α- having 6 or more carbon atoms that can be copolymerized with ethylene
Specific examples of olefins include propylene, butene-1
, 4-methylpentene-1, and octene-1.

The polymerization pressure is 200Kp/i or more, preferably 500~!
It is 7/7 in 1000. The polymerization temperature is 125°C or higher, preferably 150 to 350°C. The average residence time of the monomer within the polymerization system is 2 to 60.0 seconds.

Preferably it is 10 to 150 seconds.

As the polymerization apparatus, a tubular reactor or a seed reactor can be used.

titanium compounds and organoaluminum compounds.

They can be supplied individually or mixed in advance to a single polymerization system. It is also possible to pre-treat both 9 and 9 with ethylene or an α-olefin having 6 or more carbon atoms in the presence or absence of an inert organic solvent, and then supply the latter to the polymerization system.

The molecular weight of the polyethylene produced can be easily controlled by adding a molecular weight regulator, such as hydrogen, to the monopolymerization system.

The amount of the deactivator to be used may be sufficient to deactivate the catalyst in the 9-polymerization reaction mixture, per mole of the organoaluminum compound supplied to the 2-polymerization system.

The amount of boron or zinc in the deactivator is preferably 0.2 to 10 gram atoms, particularly 0.5 to 5 gram atoms.

There are no particular restrictions on the method of adding the quencher.

It can be added to the 1M reaction mixture by suspending or dissolving it in an inert organic solvent. Specific examples of inert organic solvents include white spirit, hydrocarbon oil, hentane,
Examples include hexane, heptane, and cyclohexane. Preferably, the quencher is added to the polymerization reaction mixture near the outlet of the reactor. Taking a tubular reactor as an example, it is preferable to add the deactivator to the polymerization reaction mixture near the pressure reducing valve provided between the two reactors and the separator.

Next, examples will be shown.

Example 1 (1) Preparation of titanium compound Aluminum chloride 1. oKg toluene slurry 151
5 tons of a toluene solution of methyl trinidoxin run 1.3 and 4 was added dropwise over 50 minutes to - at about 20°C.

The temperature was then raised to 60°C and maintained at the same temperature for 2.5 hours.

The reaction mixture was cooled to -10°C, 10 t of a solution of 7 kg of n-butylmagnesium chloride in diisoamyl ether was added dropwise to the reaction mixture over 1.7 hours, and then the temperature was raised to 25°C. Holds time. The precipitated carrier was separated from each other and washed with toluene.

8.3 A of titanium tetrachloride was added to the toluene suspension of the carrier 157, and the two were brought into contact at 90° C. for 1 hour. The obtained compatible titanium compound was distributed door to door and washed with toluene. The titanium content of the supported titanium compound was 5.2% by weight.
A monomer consisting of 40% by weight of butene and 0.2 mol of hydrogen per monomer are continuously supplied, and 2oooK
Ethylene and 1-butene were copolymerized under a pressure of q/-.

The supported titanium compound and diethylaluminium chloride were fed continuously at a rate of 56 g/hour and 8 fi'/hour, respectively, from an injection point located at the inlet of one reaction tube. Still, metaboric acid was continuously fed at a rate of say/hour from an injection point located 350 m from the inlet of one reactor.

The temperature inside the reaction tube is 150°C at the inlet and 25°C at the maximum temperature.
It was kept at 0°C. The flow rate of the monomer in the reaction tube was 10 m/sec. The polymerization reaction mixture was introduced into a separator, and unreacted monomers separated from the produced polymer were circulated and fed to the reactor.

The above continuous operation was performed for an hour. The temperature inside the reaction tube is
A significant decrease was observed after the point of quencher injection.

The yield of ethylene/butene-1 copolymer per 11 titanium compounds fed was 24,200 grams.

The density of the resulting copolymer was o, q21y/-.

No change in copolymer yield over time was observed yet.

In the following examples, 1. In order to clarify the effect of the deactivating agent used in the present invention, the deactivating agent was added from the injection point provided immediately after the injection point of the titanium compound and the organoaluminum compound. The process was otherwise carried out in the same manner as in Example 1 to copolymerize ethylene and butene-1, and the yield of the resulting copolymer was compared with that of Example 1. Calculated according to the formula.

Examples 2-6 Example 1 was repeated except that the predetermined amounts of the quenchers listed in Table 1 were fed to the reaction tubes as described above.

The results are shown in Table 1.

Table 1

Claims (1)

[Claims] Ethylene or a mixture of ethylene and an α-olefin having 6 or more carbon atoms in the presence of a catalyst obtained from a transition metal derivative and an organoaluminum compound. As a deactivating agent when polymerizing at a pressure of 200 kg/- or more and a temperature of 125° C. or more and adding the deactivating agent to the polymerization reaction mixture to deactivate the catalyst. (a) Metaboric acid (b) Boron oxide (c) An ethylene polymerization method characterized by using a compound selected from the group consisting of basic zinc carbonate.