JPS6011512A - Polymerization of ethylene - Google Patents

Abstract

PURPOSE:To obtain a polymer of a uniform quality in good yields per unit catalyst, by stabilizing the polymerization reaction by (co)polymerizing ethylene at a high temperature and a high pressure in the presence of a specified liquid Ziegler catalyst. CONSTITUTION:A magnesium compound of formula I (wherein R<1> is a 1-20C alkyl, or a 7-20C aralkyl, R<2> is an 8-10C alkyl, and 0<=l<1) with a titanium compound of formula II (wherein R<3> is 1-20C alkyl, X<1> is a halogen, and 0<=m <=4), e.g., methoxytitanium trichloride, in an inert solvent. A catalyst is prepared from the obtained titanium-containing solution and an organoaluminum compound of formula III (wherein R<4> is a 7-8C aralkyl, phenyl, or the like, and 1<n<3), e.g., diethylaluminum chloride. Ethylene or a mixture of ethylene with a 3C or higher alpha-olefin is polymerized at a pressure >=200kg/cm<2> and a temperature >=125 deg.C in the presence of the above catalyst.

Description

[Detailed description of the invention] The present invention relates to the high temperature and high pressure polymerization of ethylene.

Methods are known in which ethylene is polymerized in the presence of Ziegler-type catalysts at temperatures above 125° C. and pressures above 200 Kg/ff1. As for the above catalyst.

Titanium component 1 For example, a combination of a titanium compound supported on titanium trichloride and a magnesium compound and an organoaluminum compound has been proposed (for example,
No. 9-97087, No. 56-18607, No. 57-1
No. 90009).

Since all the titanium components used in the proposed method are solid, there is a problem (2) as described below. 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, preparing a homogeneous titanium component slurry is difficult in itself, and even if a uniform slurry can be prepared, the solid titanium component tends to settle in the transport pipe, and the titanium component cannot be quantitatively determined in one polymerization reactor. It is extremely difficult to provide a reliable supply. Since the amount of titanium component supplied to the polymerization reactor is not constant, the stability of one polymerization reaction is lost. In particular, if the titanium component is supplied in excess, the monopolymerization 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 invention satisfies the above needs.

That is, in the present invention, ethylene or a mixture of ethylene and an α-olefin having 6 or more carbon atoms is used in the presence of a catalyst obtained from the following components CAI and CI.

This is an ethylene polymerization method characterized by polymerization at a temperature of 125° C. or higher under a pressure of 200 K7/i or higher.

Component [A] Formula R2 (OR2)2-1 CI] (R1
represents an alkyl group having 1 to 20 carbon atoms or an aralkyl group having 7 to 20 carbon atoms, + R2 represents an alkyl group having 8 to 10 carbon atoms, and t is a number greater than or equal to 0 and less than 1. ), and a magnesium compound represented by the formula (R3o)mTix4-m c H] (in the formula R3
represents an alkyl group having 1 to 20 carbon atoms.

Xl represents a rogen atom, and 1m is a number of 0 or more and 4 or less. ) A titanium-containing solution obtained by contacting a titanium compound represented by the following formula in the presence of an inert hydrocarbon solvent.

Component [B] Formula R'nAtX"3-n [IIT] (in the formula H4
is an alkyl group having 1 to 8 carbon atoms, a phenyl group or 7 carbon atoms
~10 aralkyl groups.

n is a number greater than 1 and smaller than O. ) is an organoaluminum compound represented by

According to the present invention, an excellent effect similar to that of a manure can be achieved.

(1) Since both component [A] and component [B] are liquid, they can be easily supplied to a single polymerization reactor.

(2) Component [A] and component [B] can be quantitatively supplied to the polymerization reactor.

(3) It is easy to control the supply amounts of component [A] and component [B] in response to pressure fluctuations in the polymerization reactor.

(4) Since component [A] and component [B] are well dispersed in the polymerization reactor, a polymer of uniform quality can be obtained.

(5) Significantly higher yields of polymer are obtained per catalyst used.

In the present invention, component [A] is prepared under an inert gas atmosphere such as nitrogen or argon.

The magnesium compound represented by the formula CI] can be prepared by a known method 1, for example, a reaction between metallic magnesium and an alcohol, or a reaction between a dialkylmagnesium and an alcohol.

A specific example of the group represented by R1 is a methyl group.

Examples include ethyl group, n-butyl group, n-hexyl group+n-octyl group, n-decyl group, n-dodecyl group, n-octadecyl group, and benzyl group.

Specific examples of the group represented by R2 include 2-ethyl-n
-hexyl group, 1-ethyl-n-hexyl group, 1-ethyl-n-octyl group, 2-ethyl-n-heptyl group, 2
-ethyl-4-methyl-n-heptyl group, 1-ethyl-
Examples include n-heptyl group, In-octyl group, and n-decyl group. Among these, carbon number 8 to 10 with one branch
The alkyl group is preferably used.

In the present invention, compounds in which L in formula 2 [■] is 1.8 to 2 are preferably used.

Specific examples of titanium compounds represented by the formula [nl are:
Methoxytitanium trichloride, ethoxytitanium trichloride, butoxytitanium trichloride, octoxytitanium trichloride, dodecoxytitanium trichloride, ethoxytitanium tribromide, ethoxytitanium trichloride.

Jetoxytitanium dichloride, dibutoxytitanium dichloride, dihexoxytitanium dichloride, triethoxytitanium chloride, tributoxytitanium chloride, trihexoxytitanium chloride, trioctoxytitanium chloride, tetramethoxytitanium, tetraethoxytitanium, tetrabutoxytitanium, Trioctoxytitanium is 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 the magnesium compound.

There is no particular restriction on the method of bringing the magnesium compound and titanium compound into contact, and the following methods can be employed.

(1) A method of adding a titanium compound to a solution of a magnesium compound in an inert organic solvent.

(2) A method of adding the above solution to a titanium compound.

(3) A method of adding a solution of a titanium compound in an inert organic solvent to the above solution.

(4) A method of adding a solution of a magnesium compound to a solution of a titanium compound.

A specific example of an inert organic solvent is hexane.

Haflin. Aliphatic hydrocarbons such as higher alkanes.

Examples include aromatic hydrocarbons such as benzene, toluene, and xylene, and their compounds.

Contact temperature is 80°C to 300°C, preferably 10 to 20°C.
It is 0°C. The contact time is not particularly limited and is usually 5 minutes or more.

The titanium-containing solution obtained in this way is used as is.

Alternatively, dilute with an inert organic solvent if necessary.

Subjected to polymerization reaction.

Organoaluminum compound (component [■]) represented by the formula [■]
Specific examples of B]) include diethylaluminum chloride, dibutylaluminum chloride, diethylaluminum chloride, diethylaluminum bromide, diethylaluminum iodite, diphenylaluminum chloride, ethylaluminum sesquichloride, butylaluminum sesquichloride, phenylaluminum sesquichloride, Examples include benzylaluminum chloride.

The amount of organoaluminum compound used is usually 1 to 1000 moles per gram atom of titanium in the titanium-containing solution.

In the present invention, in the presence of a catalyst obtained from component [A] and component [B], ethylene or ethylene and 3-carbon
The mixture with the above α-olefin is polymerized to obtain an ethylene homopolymer or an ethylene copolymer.

Specific examples of α-olefins having 6 or more carbon atoms include propylene, butene-1,4-methylpentene-1, and octene-1.

Polymerization pressure is 200Kg/- or more, preferably 500-3
000 is 97-. The polymerization temperature is 125°C or higher, preferably 150 to 350°C. Seven polymers in the polymerization system
The average residence time is 2 to 600 seconds.

Preferably it is 10 to 150 seconds.

As the polymerization apparatus it is possible to use a tube reactor or a seed reactor.

The molecular weight of the polyethylene produced can be easily adjusted by adding a molecular weight regulator, such as hydrogen, to the monopolymerization system (9).

Next, examples will be shown. In the examples, "polymerization activity" means the yield (Kg) of polyethylene per 11 titanium in the component [A] used, and 1M,
According to D 123B, 190 °C under a load of 2.16 to 9
This is the melting index of polyethylene measured at

Example 1 (1) Preparation of titanium-containing solution (component [A]) 13.2 t of n-hebutane solution containing 7.7 mol of 2-ethylhexanol
After adding 2 tons of a solution of 2.5 mol of dihexylmagnesium in n-heptane at 10°C over a period of time, the temperature was raised to 90°C and the mixture was reacted for 1 hour.

To the obtained di-2-ethylhexoxymagnesium solution, 0.35 mol of tetra-n-butoxytitanium was added with stirring at room temperature over 60 minutes to obtain a titanium-containing solution.

The concentration of titanium in the solution was 0.023 gram atoms/l. Add this solution to Scherzl 71 (Shell Chemical Exhibition) 3
Dilute with 1.71 and prepare as component [A].

(10) (2) Polymerization A monomer consisting of 60% by weight of ethylene and 140% by weight of butene, and hydrogen at 0.2VOt% relative to the monomer were continuously supplied to a reaction tube with a total length of about 400m, and 2000K
Ethylene and butene-1 were copolymerized under pressure of g/ctA.

Scherzl 71 solution of diethylaluminum chloride as the above component [A] and component [B] (concentration: 450
mmol/l), respectively 4t/h and 3.517
It was continuously fed from an injection point provided at the inlet of one reaction tube at a rate of 1 hour.

The temperature inside the reaction tube is 140°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 above continuous operation was carried out for 5 hours. An ethylene/butene-1 copolymer with a density of 0.921 y/crA and a polymerization activity of 820 was obtained.

Example 2 and Example 1 was repeated except that the amount of 2-ethylhexanol used was varied as described in Table 1. The results are shown in Table 1. 2-Ethylhexanol and Table 1 Examples 4 and 5 Example 1 was repeated, except that 7.7 moles of the alcohol listed in Table 2 were used instead of 2-ethylhexanol.

The results are shown in Table 2.

Table 2 Examples 6 and 7 Example 1 was repeated, except that 0.35 mol of the titanium compound listed in Table 2 was used instead of tetra-n-butoxytitanium. The results are shown in Table 2.

Table 1 (13)

Claims (1)

[Claims] Ethylene or a mixture of ethylene and an α-olefin having 3 or more carbon atoms is heated under a pressure of 200 Kg/crA or more in the presence of a catalyst obtained from the following components [A] and [B]. A method for polymerizing ethylene, which is characterized by polymerizing at a temperature of 125°C or higher. Component [A, ] Formula RzMy+(OR2)2. + (In the formula, R1 represents an alkyl group having 1 to 20 carbon atoms or an aralkyl group having 7 to 20 carbon atoms, and R2 has 8 to 10 carbon atoms.
represents an alkyl group, and t is a number greater than or equal to 0 and less than 1. ), and a magnesium compound represented by the formula (,u3o)mTlxj-. (In the formula, +R3 represents an alkyl group having 1 to 20 carbon atoms. Xl represents a halogen atom, and 1m is a number from 0 to 4.)
+ titanium-containing solution obtained by contacting in the presence of a hydrocarbon solvent. Component [B] Formula R'HAJ, An organoaluminum compound represented by a small number.