JPH04359003A - Production of polypropylene - Google Patents

Abstract

PURPOSE:To obtain an isotactic polypropylene having high melting point in high efficiency by polymerizing propylene in the presence of hydrogen using a catalyst composed of a Ti compound having a specific structure and an aluminoxane. CONSTITUTION:Propylene is polymerized preferably at -30 to +100 deg.C under a pressure of normal pressure to 50kg/cm<2>G in the presence of hydrogen using a catalyst containing, as active components, (A) a titanium compound of formula I (Y is Si, Ge, etc.; R<1>n-C5H4-n and R<1>q-C5H4-q are substituted cyclopentadienyl; n and q are 0-4; n and q are not simultaneously; R<1> is silyl or hydrocarbon group; R<2> is H or hydrocarbon group; X is H, halogen, etc.) [e.g. dimethylsilylbis(methylcyclopentadienyl)-titanium dichloride] and (B) an aluminoxane of formula II or formula III (m is 0-100; R<3> is hydrocarbon group).

Description

[Detailed description of the invention]

0001

[Industrial Application Field] The present invention involves the polymerization of propylene in the presence of hydrogen using a catalyst consisting of a titanium compound having a bis-substituted cyclopentadienyl bridged bidentate ligand with a bridged structure and aluminoxane. Regarding how to.

0002

[Prior Art] As a homogeneous catalyst for olefin polymerization,
The so-called Kaminsky catalyst is well known. Using this catalyst system, it is possible to produce polypropylene exhibiting various stereoregularities, such as isotactic polypropylene and syndiotactic polypropylene, in the polymerization of propylene.

[0003] Kaminski et al. have reported that polypropylene exhibiting high isotactic properties can be produced using a zirconium compound having a chiral ligand (for example, JP-A-61-264010, JP-A-64-514).
08, Japanese Unexamined Patent Publication No. 64-66216).

Furthermore, Yuen et al. reported that when propylene was polymerized using a transition metal compound having a compound in which a cyclopentadienyl group and a fluorenyl group were crosslinked with an isopropyl group as a bidentate ligand, syndiotactic polypropylene was obtained. What can be obtained (J.Am.Chem.Soc
．． 1988, 110, 6255-6256) has been reported. Furthermore, it is known that isotactic polypropylene can be produced using chiral transition metal compounds having silicon-bridged bis-substituted cyclopentadienyl ligands (for example, JP-A-1-301704, JP-A-3
-12407 publications).

From the above reports, it has been concluded that zirconium and hafnium are suitable transition metals to be used as catalysts for the polymerization of propylene in view of polymerization activity and the like. On the other hand, when propylene is polymerized using titanium as the transition metal in the catalyst system as described above, there are disadvantages in that the resulting polymer has a low melting point and even poor activity.

[0006]

[Problems to be Solved by the Invention] As a result of repeated research to solve the above problems, the present inventors found that by adding hydrogen to the polymerization system when polymerizing propylene using a Ti compound, It was discovered that polypropylene with a high melting point can be efficiently produced, and the present invention was achieved based on this knowledge.

[0007]

[Means for Solving the Problems] That is, the present invention provides (
A) Titanium compound represented by general formula (1)

[0008]

embedded image (However, Y represents silicon, germanium or tin. R1n-C5H4-n and R1q-C5H4-q represent substituted cyclopentadienyl groups, and n and q are integers of 0 to 4. However, n = q = 0 is excluded. Each R1 may be the same or different from each other and represents a silyl group or a hydrocarbon group. Each R2 may be the same or different from each other,
Indicates a hydrogen or hydrocarbon group. Further, X may be the same or different, and represents hydrogen, halogen, an alkyl alkoxy group, or a hydrocarbon group. ) and (B) general formula (2
) or aluminoxane represented by (3)

0009
]

Production of polypropylene, characterized by polymerizing propylene in the presence of hydrogen using a catalyst containing as an active ingredient: Regarding the method. The present invention will be described in detail below.

The catalyst component (A) used in the method of the present invention is a titanium compound having a bis-substituted cyclopentadienyl bridge type bidentate ligand having a bridge structure represented by the general formula (1). be.

[0011]

embedded image Y is silicon, germanium, or tin. The number of substituents R1 on the two cyclopentadienyl rings may be any number from unsubstituted to 4 substituted, but at least one of the cyclopentadienyl rings must have a substituent. R1 may be the same or different from each other,
Indicates a silyl group or a hydrocarbon group. Examples of the silyl group include trimethylsilyl group, triethylsilyl group, triphenylsilyl group, and the like. Examples of hydrocarbon groups include (alkyl groups having 1 to 20 carbon atoms, alkenyl groups, aryl groups, alkylaryl groups, arylalkyl groups, etc.), specifically, methyl groups, ethyl groups, propyl groups, isopropyl groups, etc. group, butyl group, sec-butyl group, tert-butyl group, phenyl group, tolyl group, biphenyl group, naphthyl group, etc. Each R2
may be the same or different and are hydrogen or the above-mentioned hydrocarbon groups. Further, X is hydrogen, a halogen such as fluorine, chlorine, bromine, or iodine, an alkyl alkoxy group, or the above-mentioned hydrocarbon group.

Typical synthesis of the titanium compound represented by the general formula (1) used in the present invention is carried out by the following general reaction. Taking n=q=1 as an example, it can be abbreviated as follows.

[0013]

[Image Omitted] Non-limiting examples of the titanium compound represented by the above general formula (1) include dimethylsilylbis(methylcyclopentadienyl)titanium dichloride, dimethylsilylbis(methylcyclopentadienyl)titanium dibromide, Diphenylsilylbis(methylcyclopentadienyl) titanium dichloride, diphenylsilylbis(methylcyclopentadienyl) titanium dibromide, dimethylsilylbis(methylcyclopentadienyl) titanium dimethyl, diphenylsilylbis(methylcyclopentadienyl) Titanium dimethyl, dimethylsilylbis(methylcyclopentadienyl) titanium diphenyl, diphenylsilylbis(
methylcyclopentadienyl) titanium diphenyl, dimethylsilylbis(isopropylcyclopentadienyl)
Titanium dichloride, dimethylsilylbis(isopropylcyclopentadienyl) titanium dibromide, dimethylsilylbis(isopropylcyclopentadienyl) titanium dimethyl, dimethylsilylbis(isopropylcyclopentadienyl) titanium diphenyl, diphenylsilylbis(isopropylcyclopentadienyl) Dienyl) titanium dichloride, diphenylsilylbis(isopropylcyclopentadienyl)titanium dibromide, diphenylsilylbis(isopropylcyclopentadienyl)titanium dimethyl, diphenylsilylbis(isopropylcyclopentadienyl)titanium diphenyl, dimethylsilylbis(
t-butylcyclopentadienyl) titanium dichloride, dimethylsilylbis(t-butylcyclopentadienyl) titanium dibromide, dimethylsilylbis(t-butylcyclopentadienyl) titanium dimethyl, dimethylsilylbis(t-butylcyclopentadienyl) titanium dibromide pentadienyl) titanium diphenyl, diphenylsilylbis(t-butylcyclopentadienyl) titanium dichloride, diphenylsilylbis(t-butylcyclopentadienyl) titanium dibromide, diphenylsilylbis(t-butylcyclopentadienyl) Titanium dimethyl, diphenylsilylbis (t
-butylcyclopentadienyl) titanium diphenyl, dimethylsilylbis(dimethylcyclopentadienyl) titanium dichloride, dimethylsilylbis(dimethylcyclopentadienyl) titanium dibromide, diphenylsilylbis(dimethylcyclopentadienyl) titanium dichloride, Diphenylsilylbis(dimethylcyclopentadienyl) titanium dibromide, dimethylsilylbis(dimethylcyclopentadienyl) titanium dimethyl, diphenylsilylbis(dimethylcyclopentadienyl) titanium dimethyl, dimethylsilylbis(dimethylcyclopentadienyl) Titanium diphenyl, diphenylsilylbis(dimethylcyclopentadienyl) titanium diphenyl,
Dimethylsilylbis(diisopropylcyclopentadienyl) titanium dichloride, dimethylsilylbis(diisopropylcyclopentadienyl) titanium dibromide,
Dimethylsilylbis(diisopropylcyclopentadienyl) titanium dimethyl, dimethylsilylbis(diisopropylcyclopentadienyl) titanium diphenyl, diphenylsilylbis(diisopropylcyclopentadienyl) titanium dichloride, diphenylsilylbis(diisopropylcyclopentadienyl) titanium dibromide,
diphenylsilylbis(diisopropylcyclopentadienyl)titanium dimethyl, diphenylsilylbis(diisopropylcyclopentadienyl)titanium diphenyl,
Dimethylsilylbis(di-t-butylcyclopentadienyl) titanium dichloride, dimethylsilylbis(di-t-
butylcyclopentadienyl) titanium dibromide, dimethylsilylbis(di-t-butylcyclopentadienyl)
Titanium dimethyl, dimethylsilylbis(di-t-butylcyclopentadienyl) titanium diphenyl, diphenylsilylbis(di-t-butylcyclopentadienyl) titanium dichloride, diphenylsilylbis(di-t-butylcyclopentadienyl) titanium dichloride Bromide, diphenylsilylbis(di-t-butylcyclopentadienyl)titanium dimethyl, diphenylsilylbis(di-t-butylcyclopentadienyl)titanium diphenyl, and the like.

Another catalyst component (B) used in the present invention is an aluminoxane represented by general formula (2) or (3).

[0015]

embedded image R3 is a hydrocarbon group such as a methyl group, an ethyl group, a propyl group, a butyl group, and preferably a methyl group or an ethyl group. m is an integer from 0 to 100, preferably 6 or more, particularly preferably 10 or more. Methods for producing this type of compound are known, and include (1) compounds with adsorbed water, salts containing water of crystallization (magnesium sulfate hydrate,
A method of adding trialkylaluminium to a suspension of copper sulfate hydrate, aluminum sulfate hydrate, etc.) in a hydrocarbon medium and reacting it, or (2) directly reacting water with trialkylaluminium in a hydrocarbon medium. A method can be exemplified.

Propylene polymerization using the catalyst consisting of the components (A) and (B) described above can be carried out either in the liquid phase or in the gas phase. When polymerization is carried out in a liquid phase, solvents include (A) and (B).
) It is preferable to use an inert solvent that can dissolve both components. Any inert solvent used in the art can be used, but in particular aliphatic hydrocarbons having 4 to 20 carbon atoms, alicyclic hydrocarbons, aromatic hydrocarbons, halogenated solvents, etc. Hydrocarbons such as hexane, heptane, octane, decane, cyclohexane, benzene, toluene, o-xylene, p-xylene, m-xylene, ethylbenzene, butylbenzene, mesitylene, naphthalene, chlorobenzene, dichloromethane, dichloroethane, kerosene, and gasoline. Examples include. Particularly preferred are toluene and xylene. It is also possible to use liquefied propylene itself as a solvent.

The catalyst components used in the polymerization may be supplied to the reaction system as a mixture of components (A) and (B), or both components (A) and (B) may be supplied to the reaction system, respectively. It may be supplied separately. In either case, there is no particular restriction on the concentration or molar ratio of both components in the polymerization system, but preferably the transition metal concentration is 10-2 to 10-
The molar ratio of Al/transition metal atoms is 10 or more, particularly preferably 1000 or more.

There are no particular restrictions on the hydrogen and propylene pressures in the reaction system, but they are preferably normal pressure to 50 kg/cm.
2G range, and there is no limit to the polymerization temperature, but usually,
The temperature range is -100 to 230°C, preferably -30 to 100°C. Further, when adding hydrogen, hydrogen may be mixed with propylene in advance, or hydrogen and propylene may be separately supplied to the reaction system.

[0019]

[Examples] Next, the present invention will be specifically explained with reference to Examples, but the present invention is not limited thereto.

Example 1 All reactions for synthesizing dimethylsilylbis(3-methylcyclopentadienyl)titanium dichloride were carried out under an inert gas atmosphere. Moreover, the reaction solvent used was one that had been dried in advance. In a 200 ml glass reaction vessel, a solution of 10.5 g (48.3 mmol) of dimethylbis(methylcyclopentadienyl)silane dissolved in 40 ml of hexane was added to 68.6 ml (106 ml) of a 1.55 M hexane solution of n-butyllithium. .3mm
ol) at -50°C. The temperature was raised to -10°C, and the precipitated solid was filtered to form a white solid dimethylsilylbis(3-methylcyclopentadienyllithium)7.
2g was obtained.

In a 200 ml glass reaction vessel, 35 ml of tetrahydrofuran was cooled to -78°C, and 1.5 g (13.7 mmol) of titanium tetrachloride was added thereto. Next, 3.1 g (13.7 mmol) of the above white solid was dissolved in 150 ml of tetrahydrofuran, and slowly added dropwise at -78°C. The temperature was slowly raised to room temperature, and the mixture was heated under reflux for 1 hour. After cooling, the solvent was distilled off from the reddish-brown solution, 150 ml of toluene was added, the resulting white solid was filtered off, and the resulting filtrate was concentrated to dryness to obtain a reddish-brown solid. Recrystallization was performed with a toluene-hexane mixed solution to obtain 0.3 g of a reddish brown solid.

Example 2 In an autoclave with an internal volume of 2 L that was sufficiently purged with nitrogen, 450 ml of purified toluene, 80 mmol of methylaluminoxane (average molecular weight 1121) manufactured by Tosoh Akzo Co., Ltd. in terms of aluminum atoms, and dimethylsilylbis (
0.02 mmol of 3-methylcyclopentadienyl) titanium dichloride was sequentially added, and hydrogen was added at 0.5 kg/
cm2G, then propylene at 8K
500 ml of the solution was introduced at a rate of g/cm2G, and polymerization was carried out at 20°C for 3 hours. After the reaction, the catalyst component was decomposed with hydrochloric acid and ethanol, and the resulting polypropylene was washed with ethanol and then dried at 80° C. overnight. As a result, 4.08 g of isotactic polypropylene was obtained. Catalytic activity was 68 g/mmolTi·h. Moreover, the melting point of the polymer was 134°C.

Comparative Example 1 In an autoclave with an internal volume of 2 L that was sufficiently purged with nitrogen, 450 ml of purified toluene, 80 mmol of methylaluminoxane (average molecular weight 1121) manufactured by Tosoh Akzo Co., Ltd. in terms of aluminum atoms, and dimethylsilylbis (
0.02 mmol of 3-methylcyclopentadienyl) titanium dichloride was sequentially added, and 8 kg of propylene was added.
500ml was introduced at a rate of /cm2G, and polymerization was carried out at 20°C for 3 hours. After the reaction, the catalyst component was decomposed with hydrochloric acid and ethanol, and the resulting polypropylene was washed with ethanol and then dried at 80° C. overnight. As a result, 0.96 g of isotactic polypropylene was obtained. Catalytic activity was 16 g/mmolTi·h. Moreover, the melting point of the polymer was 128°C.

Example 3 In an autoclave with an internal volume of 2 L that was sufficiently purged with nitrogen, 450 ml of purified toluene, 80 mmol of methylaluminoxane (average molecular weight 1121) manufactured by Tosoh Akzo Co., Ltd. in terms of aluminum atoms, and dimethylsilylbis (
0.02 mmol of 3-methylcyclopentadienyl) titanium dichloride was sequentially added, and hydrogen was added at 0.5 kg/
cm2G, then propylene at 8K
500 ml of the solution was introduced at a rate of g/cm2G, and polymerization was carried out at 40°C for 3 hours. After the reaction, the catalyst component was decomposed with hydrochloric acid and ethanol, and the resulting polypropylene was washed with ethanol and then dried at 80° C. overnight. As a result, 7.2 g of isotactic polypropylene was obtained. Catalytic activity was 120 g/mmolTi·h. Moreover, the melting point of the polymer was 124°C.

Comparative Example 2 In an autoclave with an internal volume of 2 L that was sufficiently purged with nitrogen, 450 ml of purified toluene, 80 mmol of methylaluminoxane (average molecular weight 1121) manufactured by Tosoh Akzo Co., Ltd. in terms of aluminum atoms, and dimethylsilylbis (
0.02 mmol of 3-methylcyclopentadienyl) titanium dichloride was sequentially added, and 8 kg of propylene was added.
500ml was introduced at a rate of /cm2G, and polymerization was carried out at 40°C for 3 hours. After the reaction, the catalyst component was decomposed with hydrochloric acid and ethanol, and the resulting polypropylene was washed with ethanol and then dried at 80° C. overnight. As a result, 3.18 g of isotactic polypropylene was obtained. Catalytic activity was 53 g/mmolTi·h. Moreover, the melting point of the polymer was 120°C.

[0026]

According to the present invention, propylene can be produced in the presence of hydrogen using a catalyst consisting of a titanium compound having a bis-substituted cyclopentadienyl bridged bidentate ligand having a bridged structure and aluminoxane. Through polymerization, isotactic polypropylene with a high melting point can be efficiently produced, and its industrial value is high.

Claims (1)

[Claims] Claim 1: A titanium compound represented by the general formula (1) [Formula 1] (where Y represents silicon, germanium or tin. R1n-C5H4-n and R1q-C5H4-q are substituted cyclopentadienyl n and q are integers from 0 to 4.However, n=q=0 is excluded.Each R1 may be the same or different from each other and represents a silyl group or a hydrocarbon group.Each R2 and (B) General formula(
2) or (3) in the presence of hydrogen using a catalyst containing as an active ingredient an aluminoxane [Chemical formula 2] (where m is an integer of 0 to 100 and R3 represents a hydrocarbon group). A method for producing polypropylene, which comprises polymerizing propylene.