JPH03188108A - Method for polymerizing alpha-olefin - Google Patents

Abstract

PURPOSE:To inhibit the formation of by-products, such as oligomers, by polymerizing an olefin in the presence of a highly active catalyst which is obtd. by bringing a solid component comprising a chromium component carried by an inorg. oxide into contact with a specific inert hydrocarbon-sol. organomagnesium complex compd. CONSTITUTION:A solid component obtd. by baking a chromium compd. (e.g. chromium trioxide) carried by an inorg. oxide (e.g. silica) is brought into contact with an inert hydrocarbon-sol. organomagnesium complex compd. of formula I (wherein alpha, beta are each a number higher than 0; p+q+r+s+t=3alpha+2beta, and they satisfy formula II; R<1>, R<2>, and R<3> are each a 1-20C hydrocarbon group; X and Y are each OR<4>, OSiR<5>R<6>R<7>, NR<8>R<9>, etc.; and R<4> to R<9> are each H or a hydrocarbon group) (e.g. a compd. of formula III) in a molar ratio of (Al+ Mg)/Cr of 0.1-10. The resulting highly active Phillips process catalyst is used to polymerize an olefin (e.g. ethylene).

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a process for the polymerization of olefins, particularly ethylene or ethylene and other α-olefins.

Specifically, the present invention is an improvement with high activity characterized by using a catalyst obtained by contacting a solid consisting of a chromium component supported on an inorganic oxide and a component containing a specific organomagnesium. The present invention relates to a method for polymerizing olefins.

(Prior Art) An ethylene polymerization catalyst obtained by supporting a chromium compound such as chromium oxide on an inorganic oxide carrier such as silica or silica alumina and firing it is widely known as a so-called Phillips type catalyst.

However, when using this catalyst, the activity of the catalyst and the average molecular weight of the polymer greatly depend on the polymerization temperature. In order to manufacture it, the polymerization temperature must be set at 100~
It needed to be 200'C.

When polymerization is carried out in such a temperature range, the produced polymer is dissolved in the reaction solvent, so the viscosity of the reaction system increases significantly, and as a result, the concentration of the produced polymer decreases by 2.
It was difficult to raise it above 0%. Therefore, there has been a strong demand for the development of a catalyst that exhibits high catalytic activity at a polymerization temperature of 100° C. or lower, at which polymerization becomes so-called slurry polymerization.

Furthermore, in order to reduce production costs, it is important to be able to omit the catalyst removal step in the post-polymerization process, and for this purpose, it has been necessary to develop a catalyst that exhibits even higher activity.

Therefore, in order to improve the polymerization activity of this Phillips-type catalyst, many catalyst systems were proposed that combined organoaluminum compounds, organozinc compounds, etc. (for example,
6-22144, Japanese Patent Publication No. 43-27415, Japanese Patent Publication No. 47-23668, Japanese Patent Publication No. 49-347
No. 59, etc.), efforts have been made to improve the catalytic activity.

Furthermore, a catalyst system comprising a combination of a Phillips-type catalyst and an organomagnesium complex compound has been disclosed (for example, Japanese Patent Publication No. 59-5602, Japanese Patent Publication No. 59-5604, Japanese Patent Publication No. 59-50242, etc.); , the catalytic activity has been improved.

(Secret B to be solved by the invention) However, although the invention described in Japanese Patent Publication No. 59-5602 is an excellent technique with improved catalytic activity, a large amount of oligomers and wax components are added as by-products during polymerization. There were some drawbacks. This was a major problem to be solved from the viewpoint of cost and stable operation of the process.

(Means for Solving the Problems) As a result of various studies regarding the above problems, the present inventors have developed a solid product obtained by calcination activation of a chromium compound supported on a carrier such as silica, and a specific organomagnesium compound. It has been discovered that in the catalyst system described in Japanese Patent Publication No. 595602, in which the two are combined, the generation of oligomer and wax components can be significantly reduced by contacting them in advance in a specific molar ratio range and using them for polymerization, We have arrived at the present invention.

That is, the present invention includes: (a solid component obtained by supporting an al chromium compound on an inorganic oxide carrier and firing it; β is a number greater than 0, p, q, r
, sSt is 0 or greater than O, and 0< (s +t)/(
α+β)≦1.5 and p+q+r+s+t=3α+2β
R', R'', R' are the same or different hydrocarbon groups having 1 to 20 carbon atoms, XSY is the same or different OR', 05iRs Rh
R? , NRI represents a group selected from R9 and 5R16, R', R', R', R', R', and R are hydrogen atoms or hydrocarbon groups, and R10 represents a hydrocarbon group). In the olefin polymerization method using a catalyst comprising: (a) and (2) are brought into contact in advance at a molar ratio of CA1+Mg)/Cr in the range of 0.1 to 10, and used for polymerization. It is related.

The present invention will be explained in detail below.

As the inorganic oxide carrier used in the present invention, silica, silica-alumina, doria, zirconia, etc. can be used, but silica and silica-alumina are particularly preferred.

Examples of supported chromium compounds include chromium oxides, halides, oxyhalides, nitrates, sulfates, oxalates, acetates, alcoholades, etc. Specifically, chromium trioxide, chromyl chloride, dichromium acid potassium,
Compounds that at least partially form chromium dioxide upon calcination include ammonium chromate, chromium nitrate, chromium acetate, chromium acetylacetonate, and di-t-butylchromate. Chromium trioxide, chromium acetate, and chromium acetylacetonate are particularly preferably used.

Next, supporting and firing of the chromium compound will be explained.

The chromium compound can be supported on the carrier by known methods such as impregnation, solvent distillation, and sublimation deposition. The amount of chromium supported is 0% by weight of chromium atoms relative to the support.
．． It ranges from 0.05 to 5%, preferably from 0.1 to 3%.

The firing activation is carried out in the presence of -C and oxygen, but it can also be carried out in the presence of an inert gas or under reduced pressure. Preferably, air substantially free of moisture is used.

Firing temperature is 300"C or higher, preferably 400-90"C
Several minutes to several tens of hours, preferably 30 minutes to 1 hour in the range of 0°C
Runs for 0 hours. It is recommended to supply sufficient dry air during firing and to perform firing activation in a fluidized state.

Of course, it is also possible to use a known method of adjusting activity, molecular weight, etc. by adding titanates, fluorine-containing salts, etc. during the supporting or firing process.

Next, the inert hydrocarbon soluble organomagnesium complex compound represented by the general formula (Al3) used in the present invention will be explained.

In the above formula, the hydrocarbon groups represented by R1, R2, and R3 are:
It is an alkyl group, a cycloalkyl group, or an aryl group, such as methyl, ethyl, propyl, butyl, amyl, hexyl, octyl, decyl, dodecyl, cyclohexyl, phenyl group, etc., and an alkyl group is preferably used.

The polar group represented by XXY is an alkoxy group, a siloxy group,
It is an amino group or a sulfide group, preferably an alkoxy group or a siloxy group.

The ratio of polar groups to metal atoms (s+t)/(α+β) is greater than 0 and less than or equal to 1.5, preferably greater than or equal to 0°2, and 1.
It is less than or equal to 0.

The above-mentioned inert hydrocarbon-soluble organomagnesium complex compound is synthesized according to the published publications and publications of the present applicants. (For example, Tokuko Sho 52-367
Publication No. 91, Special Publication No. 52-36796, Special Publication No. 52-36796
6-43046, etc.) Examples of the inert hydrocarbon medium include aliphatic hydrocarbons such as hexane and heptane; aromatic hydrocarbons such as benzene and toluene; and alicyclic hydrocarbons such as didichlorohexane and methylcyclohexane. aliphatic hydrocarbons or alicyclic hydrocarbons are preferably used.

Next, a method of bringing the solid catalyst component (ie, the chromium-containing solid supported on a carrier and activated by firing) into contact with the organomagnesium component will be described.

In the contact method, the organomagnesium complex component may be added to a solid catalyst component suspended in a hydrocarbon medium, or the solid catalyst component may be added to an organomagnesium complex component.

In the present invention, the effect of the present invention, that is, the effect of reducing oligomer wax by-products, is obtained by bringing the solid catalyst component and the organomagnesium complex component into contact with each other in advance, and at that time, the molar ratio of the two is within a specific range. It is important for

(The molar ratio of both metals as Mg+Aj/Cr is 0
．． The range is from 1 to 1o, preferably from 1 to 5.

There are no particular limitations on the contact concentration and contact temperature, and the temperature range can be from room temperature to 100"C. As the contact medium, aliphatic hydrocarbons such as hexane and butane, benzene, etc. , aromatic hydrocarbons such as toluene; alicyclic hydrocarbons such as cyclohexane and methylcyclohexane; aliphatic hydrocarbons or alicyclic hydrocarbons are preferably used.

Next, a method for polymerizing olefin using the catalyst of the present invention will be explained.

Olefins that can be polymerized using the catalysts of the invention are alpha-olefins, especially ethylene. Furthermore, the catalyst of the present invention is ethylene, propylene, butene-1, hexene-1
It is also possible to use it for copolymerization with monoolefins such as, or in the presence of dienes such as butadiene and isoprene.

By carrying out copolymerization using the catalyst of the present invention, the density is 0. 91-0. It is possible to produce polymers in the range of 97 g/cd. As the polymerization method, usual suspension polymerization, solution polymerization, and gas phase polymerization are possible. In the case of suspension polymerization and solution polymerization, the catalyst is a polymerization solvent, such as an aliphatic hydrocarbon such as propane, butane, pentane, hexane, or heptane; an aromatic hydrocarbon such as benzene, toluene, or xylene; didiclohexane, or methylcyclohexane. Ethylene was introduced into the reactor together with alicyclic hydrocarbons such as 1 to 200 kg/ct of ethylene under an inert atmosphere. The polymerization can be carried out at a temperature of room temperature to 320°C.

On the other hand, in gas phase polymerization, ethylene is mixed at a pressure of 1 to 50 kg/cJ at a temperature of room temperature to 120°C using a fluidized bed, moving bed, or stirring to ensure good contact between the ethylene and the catalyst. Polymerization can be carried out by taking the following measures.

The catalyst of the present invention has a high performance, and is rated at 85゛C110kg/c.
It exhibits sufficiently high activity even under relatively low temperature and low pressure polymerization conditions such as d, and there are few oligomer and wax by-products during polymerization.The polymer produced in this case exists in the polymerization system in the form of a slurry. Therefore, the increase in viscosity of the polymerization system is extremely small.

Therefore, the polymer concentration in the polymerization system can be increased to 30% or more, and the amount of by-products such as oligomers and wax components is small, so there are great advantages such as reduction in manufacturing costs and improvement in production efficiency. Furthermore, due to its high activity, the step of removing catalyst residue from the produced polymer can be omitted.

The polymerization may be carried out by conventional one-stage polymerization using one reaction zone, or by so-called multi-stage polymerization using a plurality of reaction zones.

The polymer polymerized using the catalyst of the present invention has a wide molecular weight distribution even in normal one-stage polymerization, and has a relatively high molecular weight.
Extremely suitable for blow molding and film forming applications.

Multi-stage polymerization, in which polymerization is carried out under two or more different reaction conditions, makes it possible to produce polymers with a wider molecular weight distribution.

It is of course possible to use known techniques such as adjusting the polymerization temperature, adding hydrogen to the polymerization system, or adding an organometallic compound that tends to cause chain transfer in order to increase the molecular weight of the polymer by 1 Pliff. Furthermore, it is also possible to carry out polymerization by combining methods such as adding a titanate ester to control density and molecular weight.

Examples of the present invention will be shown below, but the present invention is not limited to these Examples in any way.

Note that ■catalytic activity in the examples refers to monomer pressure of 10
In kg/aJ, it represents the amount of polymer produced (g) per gram of chromium in the solid catalyst per hour.

■ Ml represents melt index, ASTM-D-
1238, at a temperature of 190°C and a load of 2° and 16kg.

(2) FR is the quotient obtained by dividing the value measured at a temperature of 190° C. and a load of 21.6 kg by Ml, and is known to those skilled in the art as an index representing the breadth of molecular weight distribution.

■ The amount of by-produced oligomers is expressed by selecting 1-hexene as a representative of the by-produced oligomers, and expressing it as a ratio (wt%) to the polymer produced in the reactor after polymerization.
-Hexene was analyzed by gas chromatography.

■ The amount of wax is the thermal hexane soluble content (w
t%).

(Example 1) (1) Synthesis of solid component (a): 0.4 g of chromium oxide was dissolved in 80 d of distilled water, and silica (Fuji Davison Grade 952) 2 was added to this solution.
0 g was immersed and stirred at room temperature for 1 hour. This slurry was heated to distill off water, and then dried under reduced pressure at 120°C for 10 hours. This solid was heated at 600° under a stream of dry air.
C. for 5 hours to obtain solid component (a). The obtained solid component (a) contained 1% by weight of chromium and was stored at room temperature under a nitrogen atmosphere.

(2) Synthesis of organomagnesium component
By reacting with stirring at 80 °C for 2 hours, the composition: AI), Mga<Ct Hs)s(n Ca Hq)
Organomagnesium complex corresponding to s, (A20Mg)
It was obtained as a solution containing 125 mmol on a standard basis.

Subsequently, this solution was cooled to 10° C., and 50 d of n-hebutane solution containing 50 mmol of n-octatool was added dropwise over 1 hour while cooling the reaction mixture to obtain an alkoxy-containing organomagnesium complex solution. . A portion of this solution was taken, oxidized with dry air, and then hydrolyzed to convert all alkyl groups and alkoxy groups into alcohols, which was analyzed using a gas chromatograph.

From the analytical values of ethanol, n-butanol, and n-octatool, the composition of the complex is as follows: AIMga(Ct Hs)z,t. (n Cm Hv
)i,zs(On Cs Hqt)x,ez.

(3) Contact between solid component (a) and organomagnesium component (2): 5 g of solid component (a) obtained in (1) (Cr: 0.
96 mmol 1) was suspended in 100 d of n-hebutane and stirred at room temperature, the organomagnesium complex solution obtained in (2) was 2.94 mmol based on (Al+Mg), that is, (A/!
+Mg)/Cr molar ratio equivalent to 3.0, and at room temperature 1
Allowed time to react.

(4) Polymerization 2 20μ of the solid obtained in (3) was dehydrated and deoxidized to form bexane 0
．． 1,51 with 8N, the inside was vacuum degassed and replaced with nitrogen.
into a reactor. The internal temperature of the reactor was maintained at 85°C, ethylene was added at 10 kg/cd, and the total pressure was increased to 14 kg/cd with hydrogen.
c-, the total pressure was increased to 14 kg by replenishing ethylene.
Polymerization was carried out for 2 hours while maintaining the temperature at /cd to obtain 240 g of polymer.

Catalyst activity is 600,000g polymer/gCr-hr
The amount of oligomer was 0.1 wt%, the amount of wax was 3.2 wt%, the Ml of the polymer was 0.09, and the FR was 130.

(Comparative Example) 20 mmol of the solid component synthesized in (1) of Example 1 and 0.1 mmol of the organomagnesium component synthesized in (2) [this corresponds to a (Af+Mg)/Cr molar ratio of 26] were prepared in advance. Polymerization was carried out in the same manner as in Example 1 except that the components were placed in the reactor without contact.

The polymerization results were as follows: polymer yield: 280 g, catalyst activity: 700,000, oligomer amount: 2.0 wt%, wax amount: 10.0 wt%, Mlo: 30, and FR: 140.

(Example 2) 13.80 g of di-n-butylmagnesium, composition: AN (Cz Hs)+, se (O3i H-CH3
・C! HS) 1. 6.81 g of organoaluminum compound of sll was placed in a flask of 50 (ld) with 200 Id of n-hebutane, and the mixture was heated at 80°
By reacting at C for 2 hours, composition: Aj!
Mgs, e (C1Hs) +, so (n Cm HJ
i.

. (○S i H-CHz ・Cz Hs>+,,
.

A siloxy-containing organomagnesium complex solution was synthesized.

Polymerization was carried out in the same manner as in Example 1 except that this siloxy-containing organomagnesium complex solution was used as the organomagnesium component.

The polymerization result was a polymer yield of 210 g and a catalyst activity of 52
5,000, Oligomer M O02wL%, Wanks II 3.1wL%, MIo, 12, and FR140.

(Examples 3 to 8) One cycle of ethylene polymerization was carried out in the same manner as in Example 1 except that the components and amounts of the organomagnesium complexes in Examples 1 and 2 were changed. Shown in the table.

(Example 9) In the synthesis of solid-state organisms, the UK CrosfieId
Grade EP200 (Cr
0.6wt%, AJ! Catalyst synthesis and polymerization were carried out in the same manner as in Example 1, except that silica containing 0.9 wt% was used and the calcination temperature was 800''C.

The polymerization results were as follows: polymer yield was 1200 g, catalyst activity was 830,000, oligomer amount was 0.2 wL%, wax amount was 3.8 wt%, polymer MIO was 15, and FR was 120.

(Example 10) A mixed gas of ethylene and 1-butene containing 15 mo 1% of 1-butene was used instead of ethylene, and isobutane was used as the polymerization solvent instead of hexane.
Mixed gas partial pressure 10 kg/cj, hydrogen partial pressure 1 kg/c at C
Polymerization was carried out in the same manner as in Example 1 except that cj and solvent vapor pressure were set to 23 kg/cd, and the catalyst of Example 9 was used in other respects.

The polymerization result was a polymer yield of 1230 g and a catalyst activity of 9.
60,000, oligomer IL 003 wt%, polymer MI
o, 80, and density 0°928.

(Effect of the invention) In the present invention, as a catalyst for α-olefin polymerization,
By using a highly active Phillips-type catalyst obtained by contacting a chromium component supported on an inorganic compound with a specific organomagnesium compound in advance, the effect of reducing the production of by-products such as oligomers can be obtained.

[Brief explanation of drawings]

Figure 1 shows the features of the present invention! It is a schematic flowchart showing fA. 89-

Claims (2)

[Claims] (1) (a) A solid component obtained by supporting and firing a chromium compound on an inorganic oxide carrier, (2) General formula (Al)α(Mg)β(R^1)_p(R^2)_q(
R^3) An inert hydrocarbon soluble organomagnesium complex compound represented by _rX_sY_t (wherein α, β are numbers larger than 0, p, q, r
, s, t are 0 or greater than 0, and 0<(s+t)/(α
+β)≦1.5 and p+q+r+s+t=3α+2β, R^1
, R^2, R^3 are the same or different numbers of carbon atoms from 1 to
20 hydrocarbon groups, X and Y are the same or different OR^4, OSiR^5R
Represents a group selected from ^6R^7, NR^8R^9 and SR^1^0, where R^4, R^5, R^6, R^7, R^8, and R^9 are hydrogen atoms or a hydrocarbon group, and R^1^0 represents a hydrocarbon group), in which (a) and (b) are mixed in advance at a (Al+Mg)/Cr molar ratio of 0. A method for polymerizing olefins, characterized in that contact is carried out in the range of 1 to 10, and used for polymerization. (2) In the organomagnesium complex compound of (b), X
, Y is a group selected from OR^4, OSiR^5R^6R^7, the method for polymerizing olefins according to claim (1).