JPS59140205A - Continuous polymerization of alpha-olefin - Google Patents

Abstract

PURPOSE:To prevent blockage from occurring in the system for feeding a catalyst and to produce a polymer of excellent stereoregularity stably for a long time, by feeding the catalyst to a feed pipe of an alpha-olefin to form a turbulent stream and feeding this stream to the polymerization zone. CONSTITUTION:An organoaluminum catalyst component (B) (e.g., triethylaluminum) is led through a feed line 5 to a feed line 4 and mixed with a titanium catalyst component (A) (preferably, in the form of a suspension obtained by dispersing the catalyst in a small amount of an inert solvent) to prepare a composite catalyst (numeral 2 designates a pressure cylinder). This composite catalyst is led to a feed line 3 of an alpha-olein (e.g., propylene) and the combined stream, maintained in a turbulent flow state (Reynolds number >=3,000) is fed to the polymerization zone 1. The alpha-olefin which is fed from the feed line 3 may be a portion of the total alpha-olefin, and the remaining portion of the alpha- olefin may be directly fed to the polymerization zone 1.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for continuous polymerization of α-olefin, and more specifically, the present invention relates to a method for continuous polymerization of α-olefin, and more specifically, a catalyst is introduced into a supply pipe of α-olefin and fed to a polymerization zone while forming a turbulent flow. The present invention relates to a method capable of efficiently producing talimer with high stereoregularity and bulk density continuously over a long period of time by preventing clogging during the supply process.

BACKGROUND ART Conventionally, methods have been known in which α-olefins are continuously polymerized using various composite catalysts that essentially include a titanium catalyst component and an organoaluminum catalyst component. However, when this method is carried out industrially, the polymerization reaction proceeds continuously by continuously supplying the catalyst to the polymerization zone through the catalyst supply pipe, but in this case, the catalyst supply pipe is Particularly in the vicinity of the polymerization zone inlet, clogging occurs easily, making stable continuous operation impossible.

Various methods have been proposed to solve this problem, such as a method of supplying a catalyst together with a large amount of inert hydrocarbon (Japanese Patent Publication No. 45-8425).

JP-A-57-11504). However, this method requires a step of recovering the solvent, is time-consuming, and is also economically problematic. A method has also been proposed in which the catalyst components are separately supplied to the polymerization zone, but this method has the disadvantage that the resulting polymer has low bulk density, stereoregularity, etc. As such, no satisfactory method is known yet, and furthermore, after mixing the catalyst components, especially after preparing a composite catalyst by mixing the supported titanium catalyst component and the organoaluminium catalyst component, it can be done in a relatively short time. Since it is known that catalyst performance decreases, there is a requirement that it be fed to the polymerization zone as soon as possible after mixing.

The present inventors have conducted extensive research into continuous polymerization of α-olefins in order to solve the above problems. As a result, the catalyst is α
- The present invention has been completed by discovering that all of the above problems can be solved by introducing the olefin into the supply pipe together with the olefin to form a turbulent flow.

That is, the present invention provides continuous polymerization of α-olefin using a composite catalyst that essentially includes a titanium catalyst component (A) and an organoaluminum catalyst component (B). This continuous polymerization method for α-olefin is characterized in that the α-olefin is introduced into a supply pipe connected to a polymerization zone together with some α-olefin, and is supplied to the polymerization zone while maintaining a turbulent flow state in the supply pipe.

Here, the composite catalyst used in the method of the present invention may be any type of composite catalyst that essentially includes a titanium catalyst component (A) and an organoaluminum catalyst component (B). The method of the present invention is effective for catalysts that tend to clog tubes. The specific titanium catalyst component (A) is a hexavalent or tetravalent titanium compound reduced by various methods, which is further ball milled and/or washed with a solvent (washed with an inert solvent and/or containing a polar compound). eutectic of titanium trichloride or titanium pentachloride (e.g. Ti0ts-1/3 ktcjt,
) is further co-pulverized with amines, ethers, esters, sulfur or halogen derivatives, organic or inorganic nitrogen-containing compounds, and others. The tetravalent titanium compound has the general formula 'l1 (OR')n Examples include the halogen-containing tetravalent titanium compounds shown below. Specifically, these are Ti0t4 and TiBr4.

Ti engineering. Tetrahalogenated titanium>, 'l'1(
OCH3)04 rTl(oa2n,)aZ3. Ti
(On-04H,)04, 'I'1(QC!2Ha
) Trihalogenated alkoxytitanium such as Br3, Ti
(OCH3)2C! t2゜Ti(002HJ204
+ Ti(On 04HGl)204, 'I”1(
Dihalogenated alkoxytitanium such as 002H1+)204, Ti(OCH3), OL.

Ti(0'2”5)sOt, Ti(On %Ho)B
Examples include monohalogenated trialkoxytitanium such as Ct and Ti(002H6)3Br.

Among these, it is preferable to use a material containing a high halogen content.

Further, titanium hexachloride, tetravalent titanium, or other halogenated titanium can be supported on magnesium halide, or supported on metal, metal oxide, metal chloride, or magnesium. The above catalyst components may be used in combination.

On the other hand, the organoaluminum catalyst (B) has the general formula AZR
Examples include compounds represented by 2aX2s-U. In the general formula, R2 is C! ~06 alkyl group X2 is a halogen, especially chlorine, and a represents O (a≦5.0).

Specific examples of such compounds include dimethylaluminum chloride, diethylaluminum chloride, diisopropylaluminium chloride, diisobutylaluminum chloride, dioctylaluminum chloride, ethylaluminum sesquichloride, ethylaluminum dichloride, trimethylaluminum, and triethylaluminum.

Examples include triisopropylaluminum, triisobutylaluminum, trioctylaluminum, and the like. It may also be a mixture of these.

As the catalyst, the titanium catalyst component (A) and the organoaluminum catalyst component ω) are essential, and other components can be mixed as necessary.

Further, the α-olefin used as a raw material monomer in the present invention may be any olefin without particular limitation as long as it has a double bond at the α position. Specifically, ethylene and tetrapyrene.

These include linear monoolefins such as butene-1, hexene-1, and octene-1, branched monoolefins such as 4-methyl-pentene-1, dienes such as Putadier, and various others. The invention can be effectively used for homopolymerization of these or copolymerization of various strange α-olefins. However, in the method of the present invention, as will be described later, it is preferable to pass the α-olefin in a liquid state through the supply pipe, and from this point of view, propylene and budene-1 are preferred as α-olefins. I can do it.

In the method of the present invention, the above-mentioned composite catalyst is introduced together with the α-olefin into a supply pipe connected to the polymerization zone, where a turbulent flow is formed to prevent the catalyst components from settling, and the composite catalyst is supplied to the polymerization zone in this state. is necessary. An example of this supply method will be explained below based on FIG. That is, the organoaluminum catalyst component (B) is introduced into the catalyst supply line 4 through the catalyst supply line 5, mixed with the titanium catalyst component (A) here to prepare a composite catalyst in advance, and this composite catalyst is introduced into the supply pipe 5. and combine with α-olefin. Here, the organoaluminum catalyst component (B) introduced through the catalyst supply line 5 may be used alone, but if necessary, electron donors such as amines, amides, ketones, nitriles, phosphines, phosphoramides, etc. Esters, thioethers, thioesters, acid anhydrides, acid rides, aldehydes, organic acids, etc., specifically methyl triylate, triylic acid, benzoic acid, and methyl benzoate.

It may be introduced together with ethylene glycol butyl ether or a mixture thereof. On the other hand, the titanium catalyst component (A) introduced through the catalyst supply line 4 may be in the form of a solid powder or particulate, but for convenience of operation, it may be a liquid α-olefin monomer or a small amount of inert hydrocarbon (n- It is preferable to introduce it as a slurry by suspending it in hexane, n-hebutane, etc.). According to the supply method shown in FIG. 1, the titanium catalyst component (A) and the organoaluminum catalyst component (B) are mixed in the catalyst supply line 4 to prepare a composite catalyst in advance, and then this composite catalyst is passed through the supply pipe. However, as shown in FIG. 2, the titanium catalyst component (A) and the organoaluminium catalyst component (B) may be separately introduced into the supply pipe B and combined with the α-olefin. Further, a part of the organoaluminum catalyst component (B) may be supplied to the polymerization zone 1 from another supply pipe (not shown) without being mixed with the titanium catalyst component (A).

Here, the α-olefin that merges with the catalyst components (A), I, and B or the composite catalyst prevents these catalysts, especially their solid components, from precipitating, and also prevents clogging at the entrance of the polymerization zone 1. All you have to do is fulfill your role. Therefore, it is only necessary to supply enough Asahi to achieve this purpose.
It is not necessarily necessary to use the entire amount of alpha-olefin fed to the polymerization zone.

Therefore, the amount of α-olefin supplied to the polymerization zone 1 through the supply pipe 3 may be appropriately selected between a part to the whole of the total supply amount, and the remaining amount is supplied from another supply pipe (not shown) as a catalyst component. may be supplied to the polymerization zone 1 without mixing.

Further, when introducing the catalyst into the supply pipe 3, it is preferable to provide a pressurizing cylinder 2 in the catalyst supply line 4 or 5. When the catalyst is introduced into the supply pipe 3 which normally supplies α-olefin to the polymerization zone 1 by means such as a reciprocating pump, a pulsating flow tends to occur in the supply pipe. This pulsating flow causes blockage in the vicinity of the confluence of the α-olefin in the supply pipe 6 and the catalyst, thereby interfering with stable continuous operation. Therefore, if the pressurizing tube 2 or the like is provided, the pulsating flow can be absorbed by the action of compressed gas such as nitrogen or argon inside the pressurizing tube, making it a steady flow and preventing blockage.

Since the method of the present invention requires a turbulent flow to be formed in the supply pipe 3, it is preferable that the α-olefin to be supplied be maintained in a liquid state. The temperature inside this supply pipe 6 is usually -10°C to 50°C, preferably 0°C to
It should be kept within the range of 30°C. If the temperature inside the tube becomes too high, if the pressure inside the tube is relatively low, the α-olefin may have vaporized or an excessive polymerization reaction may have proceeded. This is undesirable as there is a risk of clogging the tube.

In the method of the present invention, the turbulent flow state created in the supply pipe means that the catalyst does not precipitate but is dispersed in the α-olefin and flows, is supplied to the polymerization zone 1 without stagnation, and is maintained in the polymerization zone 1. Any condition is sufficient as long as it can prevent blockage at the inlet. In general, turbulent flow usually has a Reynolds number (
1'le) 1000 or more, but in the present invention, Re of 3000 is particularly preferred. There are various ways to create this turbulent state, and the method is adjusted depending on the supply amount, pipe diameter, viscosity, etc.

The catalyst and α-olefin thus supplied to the polymerization zone are polymerized by a conventional method. For example, in the case of bulk polymerization of propylene, the reaction temperature is 35 to 80°C.
The reaction is carried out under conditions of a reaction pressure of 15 to 40 atmospheres. Although the present invention can be applied to various polymerization methods, bulk polymerization without using a solvent is particularly preferred.

As described above, according to the present invention, stable continuous operation for a long period of time is possible without clogging of the catalyst supply pipe.

In addition, normally, the activity of a composite catalyst of titanium catalyst component (A) and organoaluminum catalyst component' (B) decreases in a relatively short time after mixing, but in the present invention, it quickly coexists with α-olefin. As a result, a decrease in activity can be prevented and higher catalytic activity can be obtained. As a result, the resulting polymer has high stereoregularity and bulk density. Since the monomer itself is used as a dispersion medium for the catalyst, there is no need for the conventional solvent recovery process, and costs can be reduced.

Therefore, the present invention is very useful in the production of polymers, particularly polyα-olefins, and can be used industrially.

Next, the present invention will be explained using examples.

Preparation Example (Preparation of Titanium Catalyst Component) 1.5 t of dry n-hebutane and 1 kg of magnesium jetoxide were charged into a 5 t stirring tank and stirred for 5 hours. To this was added 10.5 grams of carbon tetrachloride at room temperature.

Tetraisopropoxy titanium 12.9 +uj, H7J
After raising the temperature to 80°C, the reaction was carried out for 2 hours. The product obtained was washed by decanting with dry n-hebutane and then 1.5 t of dried n-hebutane was added at room temperature.

n-Butyl benzoate 3[1L9- was added thereto, 0.8 kg of titanium tetrachloride was added dropwise, and the mixture was reacted at 100°C for 2 hours. After the reaction was completed, washing with dry n-hebutane was repeated by a decanting method to obtain a solid titanium catalyst component.

Example 1 The solid titanium catalyst obtained in the above preparation sequence was suspended in dry Nihebutane at a ratio of αs f -T1/l-hebutane and pressurized with a reciprocating pump, and nitrogen gas was pressurized and sealed inside. The catalyst was introduced at a rate of 0.5 t/hr into a catalyst supply line 4 having a cylindrical pressure cylinder 2 with an inner diameter of 80 m and a volume of 1 t (see FIG. 1, the same applies hereinafter). A solution of n-heptane containing 500 mmol of dry n-heptane 1, 500 mmol of diethylaluminum chloride, 500 mmol of diethylaluminum chloride and 500 mmol of methyl triylate was introduced into this feed line 4 from another feed line 5 at α5 t/'hr. A composite catalyst was obtained, and this composite catalyst was supplied to a supply pipe 3 having an inner diameter of 5 ttm and supplying liquid propylene to the polymerization zone 1 at a rate of skg/hr. The Inolds number in this tube was about 6,500. Further, the supply pipe 3 was kept at 20°C. Polymerization zone 1 was supplied with liquid propylene at 95 kg/hr through another feed line (not shown). In the polymerization zone, bulk polymerization reaction was carried out continuously for 2 hours at 70° C. and 35 atm. The results are shown in Table 1.

Example 2 100 kg/hr of liquid propylene, the total amount of polymerization, was supplied from the supply pipe 3 through which the composite catalyst was supplied, keeping it at 10°C,
The same procedure as in Example 1 was carried out except that the inner diameter was set to Bran and no other liquid propylene was supplied. The Reynolds number within was approximately 11,000.

The results are shown in Table 1.

Comparative Example 1 Inside the supply pipe s vc into which the composite catalyst is introduced in Example 1
, 10 t/n-hepta in liquid propylene
hr, except that a total feed rate of 100 kg/hr of liquid propylene was supplied through a separate feed line (not shown).
The same procedure as in Example 1 was carried out. The results are shown in Table 1.

Comparative Example 2 In Example 1, liquid propylene was supplied at a rate of 0.5 ky/hr into the supply pipe 6 through which the composite catalyst was supplied, and 99.5 kg/hr of liquid propylene was supplied through another supply pipe (not shown).
The procedure was the same as in Example 1, except that the feed was carried out at hr. At this time, the Reynolds number inside the supply pipe 6 was 600. As a result, about 5 minutes after the start of the supply, the inlet of the supply pipe B to the polymerization zone 1 was blocked, leading to the termination of the polymerization.

[Brief explanation of the drawing]

1 and 2 are schematic diagrams of an apparatus for carrying out the method of the invention. 1... Polymerization zone, 2... Pressurizing cylinder, 3... Supply pipe. 4.5.--Catalyst supply line patent applicant Idemitsu Petrochemical Co., Ltd.

Claims (4)

[Claims] (1) When continuously polymerizing α-olefin using a composite catalyst that essentially includes a titanium catalyst component (A) and an organoaluminum catalyst component (B), at least one portion of the total amount of the composite catalyst supplied must be 1. A continuous polymerization method for α-olefins, characterized in that the α-olefins are introduced into a supply pipe connected to a polymerization zone together with another α-olefin, and the α-olefins are supplied to the polymerization zone while maintaining the inside of the supply pipe in a turbulent state. (2) The continuous polymerization method according to claim 1, wherein the Reynolds number is 3000 or more in a turbulent flow state. (3) The continuous polymerization method according to claim 1, wherein the α-olefin introduced into the supply pipe is maintained in a liquid state. (4) α-olefin> is propylene resin, buty>-11
The continuous polymerization method according to claim 1, wherein octene-1,4-methylpentene-1 or a mixture thereof is used.