KR20010082913A - Preparation of polyisobutene by bis(arylamido)group 4 catalyst compounds - Google Patents

Abstract

PURPOSE: A method for preparing polyisobutene is provided, to obtain polyisobutene in higher temperature without using a pollutant halogenated solvent. CONSTITUTION: Polyisobutene is prepared by polymerizing an isobutene monomer in non-halogenated polymerization solvent in the presence of a catalyst system comprising an amido-based IV group metal complex of the formula 1, a boron compound of the formula 2 and methyl aluminoxane of the formula 3. In the formula 1, M is Ti, Zr or Hf; Q1 and Q2 are independent each other and are a phenyl group unsubstituted or substituted with an alkyl group of C1-C30; Y is a functional group connecting M and two amido ligands for allowing them to form 5-7 polygon, and is a substituted or unsubstituted hydrocarbon; and X1 and X2 are independent each other and are a substituted or unsubstituted alkyl group of C1-C30, an alkoxide group, an aryloxide group, an amide group or a halide. In the formula 3, n is an integer of 3-40. Preferably the method comprises the steps of dissolving the isobutene monomer and the methyl aluminoxane in the polymerization solvent, and adding the complex of the amido-based IV group metal complex and the boron compound to the mixture to react them at -78 to -20 deg.C for 30-360 min; adding methanol to the reaction mixture dropwise to terminate the reaction; and washing the product with methanol several times, filtering and drying it.

Description

Preparation method of polyisobutene using amido-based Group IV metal complexes {Preparation of polyisobutene by bis (arylamido) group 4 catalyst compounds}

The present invention relates to a method for producing polyisobutene using an amido group IV metal complex compound, wherein isobutene is used as a monomer, an amido group IV group metal complex compound is used as a polymerization initiator, and a non-coordinating anion (non -coordinating anion and methylaluminoxane (MAO) as additives to produce polyisobutenes.

Polymerization of polyisobutene polymerized by the cationic polymerization method is known to produce a high molecular weight polymer only at a very low temperature of -80 ° C or less because the carbon cation, which is a polymerization active species, is considerably unstable. In addition, a Lewis acid is mainly used as a catalyst, which is variously described in the prior art. As an example, US Pat. No. 2,243,658 and US Pat. No. 2,356,128 disclose methods for preparing isobutene homopolymers and copolymers under methylchloride using aluminum (III) chloride. However, since these polymerization methods are polymerized at cryogenic temperatures, the process cost is high due to the polymerization, the catalyst is used in excess, and thus the difficulty of removing the catalyst is involved. As a polymerization solvent, a solvent containing chlorine is used. There is also a problem that is harmful to the environment.

Therefore, recently, a method for producing polyisobutene has been attempted without using an alkylaluminum catalyst and a methyl chloride solvent. For example, US Pat. No. 5,448,001 uses tris (pentafluorophenyl) boron having a large volume capable of generating a non-coordinating anion together with a metallocene catalyst as an auxiliary polymerization initiator. A method for producing polyisobutene having a weight average molecular weight of several tens of thousands using toluene as a polymerization solvent has been reported. According to a paper published by the same author ("Macromolecules", 31 , 8439 (1998)), this polymerization proceeds as a cationic polymerization reaction despite the use of a metallocene catalyst, and thus a common olefin by a metallocene catalyst. Shows differences in the coordination polymerization of and the reactor. That is, isobutene is shown to proceed with cationic polymerization using a metallocene catalyst, unlike polymerization of other olefins.

In WO 95/29940, various experiments have been reported for the polymerization of isobutene using a boron compound as a coordinating anion as an auxiliary polymerization initiator. In particular, various types of metallocene compounds containing cyclopentadiene as ligands are used as polymerization initiators, and it is reported that the difference in yield or molecular weight of the polymer is large depending on the type of metallocene compound used. . The contents of this patent are also published in "Journal of Polymer Science: Part A: Polymer Chemistry", 35 , 329-344 (1997), and the results of polymerization and polymerization of a polymer system using a metallocene compound as a polymerization initiator Analytical data is reported. However, even by such production methods, low-temperature conditions of -80 ° C are required to obtain high molecular weight polyisobutenes having a number average molecular weight of 1,000,000 or more.

There has been no report on the preparation of polyisobutene by the coordination polymerization reaction using a metallocene compound having a cyclopentadiene ligand as a polymerization initiator of isobutene.

However, in the field of producing polyolefins, studies on the synthesis and polymerization properties of not only metallocene compounds but also non-metallocene compounds having no cyclopentadiene ligands are actively conducted. As part of this study, McConville et al., "Macromolecules, 29 , 5241 (1996), report on the synthesis of amido-based metal complexes and the polymerization properties of α-olefins. Silver Shaffer et al. Also used as coordination polymerization catalysts for isobutene copolymerization in WO 98/37109.

As described above, a lot of research has been conducted on the method of preparing polyisobutene for a long time, but it is still necessary to develop a new catalyst system in order to overcome the cryogenic polymerization conditions and produce high molecular weight polyisobutene.

On the other hand, MAO is widely used as the non-coordinated anion that activates the metallocene compound in addition to the boron compound, and MAO is a polymer material produced by reacting alkyl aluminum with a small amount of water, and is a cocatalyst of a metallocene catalyst. It is known to play a very important role in the production of polyethylene or polypropylene. However, MAO has a problem that it is necessary to use an excess amount of hundreds to thousands of times for the metallocene compound which is expensive and the main catalyst. In addition, while boron compounds are widely used in cationic polymerization, examples of MAO used in cationic polymerization have not been reported.

The present invention uses an amido group IV metal complex compound, which has not yet been used as a cationic polymerization initiator, to maximize the space for the monomer to bond around the metal as much as possible to increase the polymerization initiation efficiency, which is a non-coordinated anion as an auxiliary polymerization initiator. A boron compound is used to stabilize the carbon cation, which is a polymerization active species, and a small amount of MAO is used to remove water and impurities in the polymerization system and to contribute to the stabilization of the carbon cation, thereby increasing the yield and molecular weight of the polymer. It is an object to provide a method for producing high molecular weight polyisobutene using a general organic solvent such as toluene instead of dichloromethane, which is a polar solvent, at a polymerization temperature higher than 30 to 50 ° C.

Method for producing a polyisobutene of the present invention for achieving the above object is an amido-based metal complex represented by the following formula (1), a boron compound which is a non-coordinating anion represented by the following formula (2), and methyl alumina represented by the following formula (3) It is characterized by the use of a catalyst system composed of lactic acid.

Wherein M is titanium, zirconium or hafnium,

Q ₁ and Q ₂ are phenyl groups substituted or unsubstituted with an alkyl group having 1 to 30 carbon atoms,

Y is a functional group connecting the transition metal M and two amido ligands to form a 5 to 7 hexagon, and is a substituted or unsubstituted hydrocarbon,

X ₁ and X ₂ are the same as or different from each other and are substituted or unsubstituted alkyl groups having 1 to 30 carbon atoms, alkoxides, aryloxides, amides or halides.

Wherein n is an integer of 3 to 40.

According to the present invention, after adding a boron compound which is a non-coordinating anion represented by Formula 2 to the amido-based metal complex represented by Formula 1 and activating for a predetermined time to make a complex, and the monomer isobutene and the formula (3) A polymerization step of reacting for 30 to 360 minutes at -78 to -20 deg. Adding a methanol solution to the reaction solution to terminate the reaction; And polyisobutene is prepared by washing the precipitated polymer several times with methanol, followed by filtration and drying to obtain a final polymer.

The present invention relates to a method for producing a high molecular weight polyisobutene at a higher temperature than an existing industrial production process by using an amido group IV metal complex, a non-coordinating boron compound, and MAO. The use of complex compounds improves polymerization initiation efficiency by taking advantage of the large space where monomers can bond around metals, and stabilizes carbon cations, which are polymerized active species, by using boron compounds, which are non-coordinated anions, as auxiliary polymerization initiators. Together, a small amount of MAO is used to remove water and impurities in the polymerization system and at the same time stabilize the carbon cations to increase the yield or molecular weight of the polymer.

Looking at the manufacturing method of the polyisobutene according to the present invention in more detail as follows.

First, isobutene is injected into the toluene polymerization solvent added to the reactor, and then MAO represented by Chemical Formula 3 is added. Then, the amido-based metal complex represented by Chemical Formula 1 and the boron compound represented by Chemical Formula 2 are dissolved in a small amount of dichloromethane solvent, mixed, aged for about 5 minutes, cooled to low temperature, and added to a polymerization solvent. The mixture is reacted at -100 to 0 DEG C for 30 to 360 minutes to produce polyisobutene. Preferred polymerization temperatures are from -78 to -20 deg.

Specific examples of the compound represented by Chemical Formula 1 include propylbisdimethylphenylamidotitaniumdimethyl, propylbisdiisopropylphenylamidotitaniumdimethyl and propylbisdiethylphenylamidotitaniumdimethyl. Preferred of these is propylbisdimethylphenylamidotitaniumdimethyl.

Amido-based complex compounds of the Group IV metal represented by the formula (1) has a wider space around the metal than the metallocene compound having a cyclopentadiene ligand, and easily binds to the monomer, thereby increasing the initiation effect.

In addition, specific examples of the boron compound that is a non-coordinating anion represented by Chemical Formula 2 include trityltetrakis (pentafluorophenyl) borate or trispentafluorophenyl boron. .

The boron compound, which is a non-coordinating anion represented by Formula 2, serves to stabilize the carbon cation as much as possible to increase the molecular weight of the polymer.

In addition, MAO removes a small amount of water or impurities in the polymerization solvent and stabilizes carbon cations to increase the polymerization yield or the molecular weight of the polymer.

Until now, amine-based compounds have been reported and commonly used as compounds that remove impurities present in the polymerization system. However, when the amine-based compounds are used, the molecular weight is increased but the polymerization yield is greatly reduced. On the contrary, it can be said that MAO is more effective than an amine compound in that not only the molecular weight of the polymer but also the polymerization yield are increased. In addition, MAO plays a role in continuously repeatable polymerization results in repeated polymerization experiments, which can more easily reproduce cationic polymerization that reacts sensitively to small amounts of impurities.

According to the present invention, the concentration of the amido-based metal complex is 1/1000 to 1/10000 molar ratio with respect to the isobutene monomer, and the concentration of the boron compound is 0.5 to 1.5 in a molar ratio with respect to the concentration of the amido-based metal complex. The concentration of MAO is preferably 0.5 to 10 in molar ratio.

More preferably, the concentration of the amido-based metal complex is 1/2000 to 1/5000 relative to the isobutene monomer, the concentration of the boron compound is 0.9 to 1.1 in molar ratio relative to the concentration of the amido-based metal complex, and the concentration of MAO is It is 0.5-5 in molar ratios.

As the polymerization solvent, toluene, cyclohexane, hexane or a mixture thereof may be used.

Termination of the isobutene polymerization reaction consists of adding a cold methanol solution to the reaction solution to remove the remaining catalyst.

Thus, polyisobutene can be produced in a high yield of 50-95% using a catalyst system consisting of an amido-based metal complex, a boron compound that is a non-coordinating anion, and MAO.

The number average molecular weight of the polyisobutene obtained at this time is 200,000-1,500,000, Preferably it is 400,000-1,200,000.

Hereinafter, the present invention will be described in detail with reference to Examples, but the present invention is not limited by the Examples.

Example 1

All reagents used in the experiments were stored under nitrogen atmosphere after purification. 100 mL of the reactor was subjected to reduced pressure for 2 hours, and then sufficiently substituted with argon gas. 20 ml of purified toluene and 5.64 g (100 mmol) of isobutene passed through the alumina column were added thereto, and then 0.02 ml (0.06 mmol) of MAO was added, followed by lowering the temperature to -78 ° C. 10.8 mg (0.03 mmol) of propyl bis (dimethylphenylamido) titanium dimethyl and 10.9 mg (0.03 mmol) of trityl tetrakis (pentafluorophenyl) borate The mixture was dissolved in dichloromethane, mixed, cooled to low temperature, charged into a reactor, and reacted at -78 ° C for 120 minutes. The reaction was terminated by dropwise adding a methanol solution to the reaction solution, wherein unreacted material was removed by stirring the reaction solution under air. The precipitated polymer was washed several times with methanol and then filtered and dried.

Example 2

Isobutene polymerization was carried out in the same manner as in Example 1 except that the polymerization was carried out at -50 ° C.

Example 3

Isobutene polymerization was carried out in the same manner as in Example 1 except that 0.02 mmol of the amido metal complex and the boron compound of Example 1 were used.

Example 4

Isobutene polymerization was carried out in the same manner as in Example 1 except that 0.05 mmol of the amido-based metal complex and the boron compound of Example 1 were used.

Comparative Example 1

Isobutene polymerization was carried out in the same manner as in Example 1 except that the polymerization was carried out without using MAO.

The yield, number average molecular weight, weight average molecular weight and molecular weight distribution of the obtained polyisobutene are as shown in Table 1 below.

Yield (%) Number average molecular weight (Mn) Weight average molecular weight (Mw) Molecular Weight Distribution (Mw / Mn) Example 1 80.7 1,121,000 2,309,000 2.06 Example 2 80.3 592,000 1,143,000 1.93 Example 3 60.1 855,000 2,095,000 2.45 Example 4 55.8 683,000 2,110,000 3.09 Comparative Example 1 71.8 1,000,000 2,070,000 2.07

From the results of Table 1, the amount of amido complex in the boron compound-MAO polymerization system, which is an amido group IV metal complex-non-coordinating anion, is 1/2000 to 1/2000 is most effective for the monomer, and the boron compound is It is understood that the same amount as the complexing compound is used, and the amount of MAO used is about 1/2 to about 5 for the amido complex.

As described in detail above, by using the amido group IV metal complex compound as in the present invention to increase the space that the monomer can be bonded around the metal as much as possible to increase the polymerization initiation efficiency, and as a co-polymerization initiator non A boron compound is used to stabilize the carbon cation, which is a polymerization active species, and a small amount of methylaluminoxane is used to remove water and impurities in the polymerization system and to contribute to the stabilization of the carbon cation. By increasing the polymerization temperature higher than the conventional process conditions, a high molecular weight polyisobutene can be prepared using a general organic solvent.

Claims (6)

Isobutene monomer in a non-halogen polymerization solvent using a catalyst system consisting of an amido group IV metal complex represented by the following formula (1), a boron compound represented by the following formula (2), and methylaluminoxane (MAO) represented by the following formula (3) To polymerize to produce polyisobutene. Formula 1 Wherein M is titanium, zirconium or hafnium, Q ₁ and Q ₂ are phenyl groups substituted or unsubstituted with an alkyl group having 1 to 30 carbon atoms, Y is a functional group connecting the transition metal M and two amido ligands to form a 5 to 7 hexagon, and is a substituted or unsubstituted hydrocarbon, X ₁ and X ₂ are the same as or different from each other and are substituted or unsubstituted alkyl groups having 1 to 30 carbon atoms, alkoxides, aryloxides, amides or halides. Formula 2 Formula 3 Wherein n is an integer of 3 to 40. The method of claim 1, After dissolving isobutene as a monomer and methylaluminoxane represented by Formula 3 in a non-halogen polymerization solvent, the amido group IV metal complex represented by Formula 1 is mixed with a boron compound represented by Formula 2 Adding a complex and reacting for 30 to 360 minutes at -78 to -20 캜; Adding a methanol solution to the reaction solution to terminate the reaction; And Method for producing a polyisobutene using amido-based Group IV metal complexes, characterized in that the precipitated polymer is washed several times with methanol and then filtered and dried. The method according to claim 1 or 2, A non-halogen polymerization solvent is selected from the group consisting of cyclohexane, hexane and mixtures thereof. A method for producing polyisobutene using an amido group IV metal complex compound. The method according to claim 1 or 2, A method for preparing polyisobutene using an amido group IV metal complex compound, wherein the molar ratio of the amido group IV metal complex compound represented by Formula 1 to the boron compound represented by Formula 2 is 0.9 to 1.1. The method according to claim 1 or 2, A method for producing polyisobutene using an amido group IV metal complex compound represented by Formula 1, wherein the molar ratio of the amido group IV metal complex compound represented by Formula 1 and methylaluminoxane (MAO) represented by Formula 3 is 0.5 to 5. . The method for producing polyisobutene according to any one of claims 1 to 5, wherein the number average molecular weight of the polyisobutene is 400,000 or more and 1,200,000 or less.