阅读说明：本技术 催化剂组合物和使用该催化剂组合物制备聚异丁烯的方法 (Catalyst composition and method for preparing polyisobutylene by using same ) 是由 曹东铉 许成范 金元熙 李�真 崔景信 金姬贞 于 2020-12-04 设计创作，主要内容包括：本发明涉及一种包含氧鎓离子类催化剂和添加剂的催化剂组合物、以及使用该催化剂组合物制备聚异丁烯的方法。(The present invention relates to a catalyst composition comprising an oxonium ion-based catalyst and an additive, and a method for preparing polyisobutylene using the catalyst composition.)

1. A catalyst composition comprising: a catalyst represented by the following formula 1; and nitrile additives:

[ formula 1]

In the formula 1, the first and second groups,

r is a linear C3 alkyl group, or a linear or branched C4-C12 alkyl group,

R₁to R₄Each independently hydrogen, a halogen group or an alkyl group of 1 to 20 carbon atoms substituted with halogen, and

o, p, q and r are each independently integers from 1 to 5.

2. The catalyst composition of claim 1, wherein the equivalent ratio of the catalyst represented by formula 1 and the nitrile additive is from 1:1 to 1: 200.

3. The catalyst composition of claim 1,

in the formula 1, the first and second groups,

r is a linear C3 alkyl group, or a linear or branched C4-C8 alkyl group,

R₁to R₄Each independently is a halogen radical, and

o, p, q and r are each independently an integer from 3 to 5.

4. The catalyst composition of claim 1,

in the formula 1, the first and second groups,

r is a n-propyl group or a butyl group,

R₁to R₄Each independently is F or Cl, and

o, p, q and r are each independently an integer of 4 or 5.

5. The catalyst composition of claim 1, wherein the nitrile additive is a compound represented by formula 2 below:

[ formula 2]

R₅--CN

In the formula 2, the first and second groups,

R₅is an alkyl group of 1 to 20 carbon atoms or an aryl group of 6 to 30 carbon atoms.

6. The catalyst composition of claim 1, wherein the nitrile additive is one or more selected from the group consisting of acetonitrile, propionitrile, 2-methylpropionitrile, trimethylacetonitrile, and benzonitrile.

7. A method for producing polyisobutylene, comprising the step of polymerizing isobutylene in the presence of the catalyst composition of any one of claims 1 to 6.

8. The method for producing polyisobutylene according to claim 7, wherein the polymerization is performed at a temperature of 10 ℃ to 50 ℃.

9. The method for producing polyisobutylene according to claim 7, wherein the polymerization is performed in the presence of a halogenated hydrocarbon solvent.

10. The method for producing polyisobutylene according to claim 7, wherein the catalyst represented by formula 1 is 5wtppm to 250wtppm based on the isobutylene.

11. The method for producing polyisobutylene according to claim 7, wherein the number average molecular weight of the polyisobutylene is 1,000 to 10,000 g/mol.

12. The method for producing polyisobutylene according to claim 7, wherein the molecular weight distribution of polyisobutylene is 1.5 to 3.0.

13. The method for preparing polyisobutylene according to claim 7, further comprising, after the step of polymerizing isobutylene, a step of removing the catalyst represented by formula 1 by filtering a polymerization product.

14. The method for producing polyisobutylene according to claim 13, wherein the filtering is performed using a filter comprising one or more selected from silica, diatomaceous earth, and zeolite.

Technical Field

Cross Reference to Related Applications

The present application claims the benefit based on the priority of korean patent application No.2019-0162054 filed on 6.12.2019 and korean patent application No.2019-0162055 filed on 6.12.2019. The entire contents of which are incorporated by reference into this specification.

Technical Field

The present invention relates to a catalyst composition comprising an oxonium ion-based catalyst and a nitrile additive, and a process for producing polyisobutylene using the catalyst composition.

Background

Generally, in the preparation of an oligomer or polymer by cationic polymerization of monomers, the growing polymer chain contains a reactive moiety having a positive charge. For example, the active moiety may be a carbenium ion (carbocation) or an oxonium ion.

As a catalyst or an initiator for such cationic polymerization, an aluminum-based or boron-based lewis acid is generally used. Examples of Lewis acid catalysts include AlX₃、BX₃(X ═ F, Br, Cl, I), etc., and lewis acids are corrosive substances and generate halogen components such as HCl and HF during quenching, and such halogen components remain in the product to cause a problem of product quality degradation. In addition, lewis acid catalysts require a large amount of catalyst, and in order to remove the catalyst after the reaction, a large amount of base (NaOH, KOH, NH) is used₄OH, etc.), therefore, additional washing with water is required, and a large amount of waste water is generated.

Meanwhile, examples of the monomer capable of undergoing cationic polymerization include styrene, isobutylene, cyclopentadiene, dicyclopentadiene and derivatives thereof, and typical examples include Polyisobutylene (PIB) obtained by polymerizing isobutylene.

Polyisobutenes are divided into low molecular weight, medium molecular weight and high molecular weight ranges according to the molecular weight range. The low molecular weight polyisobutylene has a number average molecular weight in the range of about 10,000 or less and is classified according to the content of carbon-carbon double bonds located at the terminal. The group of conventional Polyisobutylene (PIB) and highly reactive polybutene (HR-PB) products with a terminal carbon-carbon double bond content of 20% or less. After the terminal introduction of functional groups (> 80%) using vinylidene functional groups, highly reactive polybutenes can be used as fuel additives or engine oil additives.

For the polymerization of highly reactive polybutenes, boron-based catalysts, such as BF, have been used in the conventional art₃However, such catalysts are toxic and of the gaseous type and are difficult to handle. Further, in order to improve reactivity and selectivity, a boron-alcohol or boron-ether complex is prepared and used, but there is a problem that the activity of the catalyst is reduced with time.

Meanwhile, according to the solvent-bound organometallic catalyst (macro. rapid commu., vol.20, No.10, pp.555-559) studied by professor kuhn, university of munich in industry, although it is possible to solve the problems associated with the deterioration in product quality and corrosiveness due to toxic components of, for example, the boron-based lewis acid catalyst of the conventional art, since the reaction time is 16 hours and considerably long in order to obtain a high conversion rate, structural isomerization occurs by the reaction of a portion of the product with the catalyst with the increase of time, the exo-content (exo-content) is reduced, and thus, the competitive power is lower than that of the lewis acid catalyst.

[ Prior Art document ]

[ patent documents ]

Korean registered patent publication No.10-0486044

Disclosure of Invention

Technical problem

It is an object of the present invention to provide a catalyst composition for preparing polyisobutylene having a desirable number average molecular weight and having high exo content and exhibiting high reactivity.

It is another object of the present invention to provide a method for preparing polyisobutylene using the catalyst composition.

Technical scheme

In order to solve the above-mentioned task, the present invention provides a catalyst composition comprising: a catalyst represented by the following formula 1; and nitrile additives:

[ formula 1]

In the formula 1, the first and second groups,

r is a linear C3 alkyl group, or a linear or branched C4-C12 alkyl group,

R₁to R₄Each independently is hydrogen, a halogen group or a substituted or unsubstituted alkyl group of 1 to 20 carbon atoms, and

o, p, q and r are each independently integers from 1 to 5.

Advantageous effects

In the case of using the catalyst composition of the present invention, polyisobutylene having a high number average molecular weight, an exo content of 80 mol% or more, and excellent reactivity can be prepared.

In particular, the preparation method of the present invention has an advantage in preparing polyisobutylene in that it has an excellent polymerization conversion rate even under mild reaction conditions including room temperature and the like, by using the catalyst represented by formula 1 having an excellent catalyst activity and the nitrile compound as an additive.

In addition, the catalyst can be easily removed by a simple filtration step without directly washing the produced polyisobutylene after the polymerization reaction is completed, and the problems of generation of a large amount of wastewater during washing and deterioration of product quality due to the catalyst remaining in the product can be solved.

Detailed Description

Hereinafter, the present invention will be described in more detail to help understanding the present invention.

It should be understood that the words or terms used in the specification and claims of this invention should not be construed as meaning defined in commonly used dictionaries. It should also be understood that the words or terms should be construed as having meanings consistent with their meanings in the technical idea of the present invention, based on the principle that the inventor can appropriately define the meanings of the words or terms in order to best explain the present invention.

Catalyst composition

The catalyst composition of the present invention is characterized by comprising: a catalyst represented by the following formula 1; and nitrile additives.

[ formula 1]

In the formula 1, the first and second groups,

r is a linear C3 alkyl group, or a linear or branched C4-C12 alkyl group,

R₁to R₄Each independently is hydrogen, a halogen group or a substituted or unsubstituted alkyl group of 1 to 20 carbon atoms, and

o, p, q and r are each independently integers from 1 to 5.

In the present invention, in the case of using the catalyst represented by formula 1, a hydrogen atom between oxygen atoms reacts with isobutylene, and an ether compound (R-O-R) dissociates, and a carbocation of isobutylene is generated to initiate cationic polymerization. In this case, a hydrogen atom is located in the vicinity of the center of the catalyst in a sandwich shape, and an alkyl group (R) is present around the hydrogen atom, and therefore, isobutylene does not easily access it, and it may be difficult to initiate polymerization. Therefore, in order to make the reaction of isobutylene and hydrogen atoms easy and in order to make the cationic polymerization easily initiated, it is very important to appropriately control the carbon number and the steric size of R contained in the catalyst represented by formula 1.

Meanwhile, the dissociated ether compound (R-O-R) may be combined with a carbocation of a chain undergoing polymerization to be stabilized. In particular, unshared electron pairs of oxygen contained in the ether compound can be momentarily bound to stabilize the carbocation of the chain undergoing cationic polymerization, and in the case of dissociation from the carbocation by reverse reaction, can continue to polymerize with isobutylene to produce polyisobutylene having a desired degree of high molecular weight. However, in the case where the reactivity with a very unstable carbocation is too high, intermolecular chain transfer or reaction termination occurs, and it is difficult to control the reactivity, thus producing polyisobutylene having a low molecular weight.

As described above, the alkyl group R in the catalyst represented by formula 1 needs to be determined in consideration of the degree of contribution to stability by coupling with a carbocation when dissociating into an ether compound.

It was found in the present invention that R contained in the catalyst represented by formula 1 plays an important role in preventing the synthesis of low molecular weight polyisobutylene by polymerization termination or chain transfer in addition to contributing to the initiation step of cationic polymerization, and linear C3 alkyl groups and C4-C12 alkyl groups are used as R. Further, although the catalyst represented by formula 1 is not used according to the type of R, a nitrile compound is used as an additive for supplementation, and although the catalyst itself may be used for polymerization of polyisobutylene according to the type of R, high molecular weight and exo content may be secured by simultaneously using the additive.

Further, since the catalyst represented by formula 1 can be easily removed by a filtering method which will be explained later, the risk of dissociation of halogen from the catalyst can be effectively prevented fundamentally.

In formula 1, R is a linear C3 alkyl group, or a linear or branched C4-C12 alkyl group. In particular, R may be a linear C3 alkyl group or a linear or branched C4-C8 alkyl group, preferably, n-propyl or a linear or branched butyl group.

In formula 1, R₁To R₄May each independently be hydrogen, a halogen group or an alkyl group of 1 to 20 carbon atoms substituted with halogen, specifically a halogen group, F or Cl. For example, R₁To R₄May be all F. Further, o, p, q, and r may each independently be an integer of 1 to 5, an integer of 3 to 5, specifically 4 or 5. Most preferably, R₁To R₄May be F and o, p, q and r may be 5.

Further, an organoborate contained in the compound represented by formula 1Specifically, it may be selected from the group consisting of tetrakis (phenyl) borate, tetrakis (pentafluorophenyl) borate and tetrakis [3, 5-bis (trifluoromethyl) phenyl group]Borate and one or more of their derivatives, preferably tetrakis (pentafluorophenyl) borate.

Specifically, the catalyst represented by formula 1 may be a compound represented by formula 1-1 or formula 1-2 below, but is not limited thereto.

[ formula 1-1]

[ formulae 1-2]

The catalyst composition of the present invention comprises a nitrile additive along with the catalyst represented by formula 1.

In the present invention, the unshared electron pair of nitrogen contained in the nitrile additive has unstable properties and is susceptible to chemical changes. Therefore, the additive can bind the carbocation of the chain for a while to stabilize cationic polymerization and dissociate from the carbocation by a reverse reaction, and can promote polymerization of the carbocation with isobutylene to produce polyisobutylene having a high molecular weight even under mild reaction conditions.

If the nitrile additive is not used, there are problems in that polyisobutylene having a high molecular weight cannot be prepared and the value of the exo content, which is one of important physical properties of the product, is lower than the standard.

However, if the additive is strongly bound to the carbocation, the reverse reaction becomes difficult, the reactivity of the carbocation itself disappears, and the reaction ends. In this case, a polymer having a desired high molecular weight cannot be obtained. In this regard, for example, amine compounds, ether compounds, phosphine compounds, etc. may not be suitably used as additives, while nitrile compounds may be preferably used, as in the present invention.

In the present invention, the nitrile additive may be a compound represented by the following formula 2, but is not limited thereto.

[ formula 2]

R₅-CN

In the formula 2, the first and second groups,

R₅may be an alkyl group of 1 to 20 carbon atoms or an aryl group of 6 to 30 carbon atoms, specifically, an alkyl group of 1 to 10 carbon atoms or an aryl group of 6 to 10 carbon atoms.

Specifically, the additive may include one or more selected from acetonitrile, propionitrile, 2-methylpropionitrile, trimethylacetonitrile, and benzonitrile, and particularly, acetonitrile, benzonitrile, or a combination thereof, without limitation.

In the present invention, the equivalent ratio of the catalyst represented by formula 1 and the nitrile additive may be 1:1 to 1: 200. In particular, the nitrile additive may be 1 equivalent or more and 3 equivalents or more, and 200 equivalents or less, 100 equivalents or less, 20 equivalents or less, 10 equivalents or less, and 5 equivalents or less based on 1 equivalent of the catalyst represented by formula 1.

If the nitrile additive is 1 equivalent or more based on 1 equivalent of the catalyst represented by formula 1, the effect of using the carbocation of the nitrile additive can be sufficiently exhibited, polyisobutylene exhibiting high number average molecular weight and exo content can be efficiently produced, and reproducibility can be improved by appropriately controlling the catalyst activity. Further, if the nitrile additive is 200 equivalents or less based on 1 equivalent of the catalyst represented by formula 1, a phenomenon that the polymerization reaction is terminated early by the binding of an excessive amount of the nitrile additive to carbocation can be prevented.

In the present invention, the catalyst composition may further comprise a cocatalyst for controlling physical properties of the polyisobutylene, and in this case, all cocatalysts applicable to the preparation of polyisobutylene in the art may be used without limitation.

Method for producing polyisobutenes

The method for producing polyisobutylene of the present invention is characterized by comprising the step of polymerizing isobutylene in the presence of the catalyst composition.

In the present invention, the polymerization of isobutylene may be carried out at 10 ℃ to 50 ℃, specifically 10 ℃ or more, 15 ℃ or more, 25 ℃ or more, and 50 ℃ or less, 40 ℃ or less, 35 ℃ or less, for example, 30 ℃.

If the polymerization temperature is 0 ℃ or more, appropriate catalyst activity can be obtained, polymerization conversion can be exhibited to be excellent, and a small amount of catalyst can be used, whereas if the polymerization temperature is 50 ℃ or less, chain transfer reaction can be controlled, molecular weight and exo-content of polyisobutylene can be exhibited to be high, and polyisobutylene having high quality can be prepared.

Further, the polymerization needs to satisfy the above temperature conditions, and may be carried out for 10 minutes to 3 hours, specifically 30 minutes or more, 1 hour or more, 1.5 hours or more, and 3 hours or less, 2.5 hours or less, for example, 2 hours, at the same time.

In the present invention, the polymerization may be carried out in the presence of a halogenated hydrocarbon solvent. Further, the halogenated hydrocarbon solvent may be used together with a non-polar hydrocarbon solvent in a mixture.

As described above, in order to initiate cationic polymerization in the present invention, the hydrogen atoms present between the oxygen atoms of the catalyst represented by formula 1 need to react with isobutylene to dissociate the ether compound (R-O-R) and produce carbocation of isobutylene, and in order to keep the carbocation thus produced in an ionic state for a long time to improve polymerization reactivity, a halogenated hydrocarbon solvent having polarity may be used.

However, although the halogenated hydrocarbon solvent is advantageous at the initiation of the polymerization reaction as described above, the stability of the catalyst is lowered due to the toxicity of the halogen in a dissolved state in the halogenated hydrocarbon solvent, and the activity of the catalyst represented by formula 1 is gradually lowered with time if it is not used for polymerization immediately after mixing.

In contrast, in the case of the catalyst represented by formula 1 used in the present invention, stability in a halogenated hydrocarbon solvent such as methylene chloride is excellent, and catalyst activity is excellent although it is used for polymerization after a certain time is prepared as a catalyst composition, and high-quality polyisobutylene having a high polymerization conversion rate can be prepared.

The halogenated hydrocarbon solvent may be one or more selected from the group consisting of methyl chloride, methylene chloride, chloroform, 1-chlorobutane and chlorobenzene, but is not limited thereto.

The nonpolar hydrocarbon solvent may be an aliphatic hydrocarbon solvent or an aromatic hydrocarbon solvent. For example, the aliphatic hydrocarbon solvent may be one or more selected from butane, pentane, neopentane, hexane, cyclohexane, methylcyclohexane, heptane and octane, and the aromatic hydrocarbon solvent may be one or more selected from benzene, toluene, xylene and ethylbenzene, without limitation.

In the present invention, the catalyst represented by formula 1 may be 5wtppm to 250wtppm based on isobutylene, and particularly may be 5wtppm or more, 7wtppm or more, 9wtppm or more, 10wtppm or more, and 250wtppm or less, 100wtppm or less, 50wtppm or less, 45wtppm or less based on isobutylene.

If the catalyst represented by formula 1 is 5wtppm or more based on isobutylene, the amount of the catalyst is sufficient relative to isobutylene, and cationic polymerization can be smoothly performed, so that the polymerization conversion rate and yield of polyisobutylene can be excellent. If the catalyst represented by formula 1 is 250wtppm or less based on isobutylene, oligomerization of isobutylene due to an excessive amount of the catalyst can be suppressed and polyisobutylene having a high molecular weight can be prepared.

In the present invention, after the step of polymerizing isobutylene, a step of removing the catalyst represented by formula 1 by filtering the polymerization product may also be performed.

The catalyst represented by formula 1 used in the present invention can be effectively removed by a physical step of simple filtration, which is easier to use and remove even than the conventionally used lewis acid catalyst. In addition, by removing the catalyst by filtration, halogen that may be generated from the catalyst can be removed in advance, and polyisobutylene having a low halogen content can be obtained from the polymerization product.

The filtration may be performed using a filter comprising one or more selected from porous materials, e.g., silica, diatomaceous earth, or zeolites.

Generally, the polyisobutene thus produced is dissolved in organic solvents, such as pentane, cyclopentane, cyclohexane, heptane, octane and diethyl ether, and then washed to remove the remaining catalyst. However, in the present invention, the catalyst represented by formula 1 may be easily removed by filtration, and a separate washing step may not be performed.

In the present invention, after the step of filtering the polymerization product, a step of drying the remaining solvent may be further included.

The drying temperature may be 30 ℃ to 200 ℃, or 40 ℃ to 150 ℃, and the degree of vacuum may be 300 torr or less, 200 torr or less, or 100 torr or less. Further, the drying method is not particularly limited, and may be a usual method.

Further, in the method for producing polyisobutylene according to the present invention, the step of drying the halogenated hydrocarbon solvent before filtration may be performed alone or not. If the drying step is carried out, the drying conditions may be the same as those described above, without particular limitation.

In the case where the drying step of the halogenated hydrocarbon solvent is separately performed, polyisobutylene having even higher purity can be obtained. However, according to the present invention, since the catalyst can be easily removed by the above-mentioned simple filtration, a separate drying step of the halogenated hydrocarbon solvent after the polymerization step and before the filtration can be omitted, and there is an advantage of simplifying the process.

The polyisobutenes prepared according to the invention exhibit a high molecular weight and an exo content.

Specifically, the number average molecular weight of the polyisobutylene may be 1,000 to 10,000g/mol, specifically 1000g/mol or more, 1,300g/mol or more, 1,400g/mol or more, and 10,000g/mol or less, 7,000g/mol or less, 5,000g/mol or less.

Further, the molecular weight distribution (PDI) of the polyisobutylene can be 1.5 to 3.0, specifically 1.5 to 2.5, 1.5 to 2.0.

Further, the exo content (%) in the polyisobutylene determined by the following equation may be 80% or more. If the exo content is increased, it means that a highly reactive polyolefin, for example, a highly reactive polybutene (HR-PB), is formed.

-exo content (%) ═ (moles of exo olefins with carbon-carbon double bonds at the ends)/(moles of exo and endo olefins produced) x 100

Examples

Hereinafter, the present invention will be described in more detail with reference to embodiments. However, the following embodiments are merely examples, and the scope of the present invention is not limited thereto.

Preparation of the catalyst

Preparation of example 1

[ formula 1-1]

In a glove box, 1g of [ H (Et)₂O)₂][B(C₆F₅)₄]Into a round bottom flask and 10mL of dichloromethane was added. At room temperature, 5 equivalents of anhydrous butyl ether (Sigma-Aldrich Co.) were added and stirred for 30 minutes. After stirring, all solvent was removed under vacuum. The white powder thus obtained was washed three times by 5mL x using anhydrous hexane, and then dried again under vacuum to obtain [ H (nBu)₂O)₂][B(C₆F₅)₄]。

Preparation of example 2

[ formulae 1-2]

The same procedure as in preparation example 1 was conducted except that anhydrous butyl ether was changed to anhydrous propyl ether.

Comparative preparation example 1

In a glove box under argon, 1g of [ Li (Et)₂O)_n][B(C₆F₅)₄](TCI Co.) was added to a round bottom flask and 10mL of anhydrous diethyl ether was added. The solution thus prepared was taken out of the glove box and then connected to a Schlenk line, setting argon conditions. A cooling bath was made using acetonitrile and dry ice, and the solution thus prepared was stirred at-40 ℃. While stirring the solution, 5 equivalents of 1M HCl in ether (TCI Co.) were injected into the solution via syringe. The solution was stirred at-40 ℃ for a further 30 minutes, and the temperature was slowly raised to room temperature. The solution, the temperature of which was raised to room temperature, was again placed in a glove box, the salt thus produced was removed by filtration, and the clear solution was collected and dried under vacuum. After drying all solvents in vacuo, washed three times with 5mL x dry hexanes and dried in vacuo to give [ H (Et)₂O)₂][B(C₆F₅)₄]。

Comparative preparation example 2

The same procedure as in preparation example 1 was conducted, except that anhydrous isopropyl ether was used instead of anhydrous butyl ether.

Comparative preparation example 3

NaBAr'4 and chlorine were reacted in diethyl ether and sodium tetrakis [3, 5-bis (trifluoromethyl) phenyl ] borate was purchased from Sigma-Aldrich co.

Preparation of polyisobutenes

Example 1

An Andrew glass flask in a vacuum state was used, cooled to 10 ℃ or lower, an isobutylene line was connected, and 20g of isobutylene was charged therein. Meanwhile, 80mL of toluene solvent was injected using a syringe.

In a glove box, the catalyst of preparation example 1 (40 wtppm based on isobutylene) and benzonitrile (equivalent ratio of catalyst of preparation example 1 to benzonitrile additive 1:5) were weighed and dissolved in 0.5mL of DCM to prepare a catalyst composition.

Thereafter, the anderu glass flask was kept at a polymerization temperature of 30 ℃, and the catalyst composition was injected using a syringe. After the cationic polymerization of isobutylene was carried out for 2 hours, the product was dried to obtain polyisobutylene.

Examples 2 to 6

Polyisobutylene was prepared by the same method as in example 1, except that the polymerization conditions were changed as shown in the following table 1.

Examples 7 to 9

An Andrew glass flask in a vacuum state was used, cooled to 10 ℃ or lower, an isobutylene line was connected, and 20g of isobutylene was charged therein. At the same temperature, 80mL of toluene solvent was injected using a syringe.

In a glove box, the catalyst of preparation example 1 (40 wtppm based on isobutylene) and benzonitrile (equivalent ratio of catalyst of preparation example 1 to benzonitrile additive 1:5) were weighed and dissolved in 0.5mL of DCM to prepare a catalyst composition. The catalyst compositions were then stored at room temperature according to the respective aging times of table 1.

Thereafter, the anderu glass flask was kept at a polymerization temperature of 30 ℃, and the catalyst composition was injected using a syringe. After the cationic polymerization of isobutylene was carried out for 2 hours, the product was dried to obtain polyisobutylene.

Comparative examples 1 to 11

Polyisobutylene was prepared by the same method as in example 1, except that the polymerization conditions were changed as shown in the following table 1.

[ Table 1]

Experimental example 1

For the polyisobutenes obtained in the examples and comparative examples, the physical properties were measured by the following methods.

(1)Polymerization conversion (%)

The weight of the dried polyisobutene was measured and the conversion was calculated.

(2)Appearance content (%)

Measurement Using Varian 500MHz NMR¹H NMR, and the shapes of the exo-type olefin and the endo-type olefin were confirmed from the position of the double bond, and the exo content (%) was calculated according to the following equation.

-exo content (%) ═ (moles of exo olefins with carbon-carbon double bonds at the ends)/(moles of exo and endo olefins produced) x 100

(3)Weight average molecular weight (Mw) and Molecular Weight Distribution (MWD)

The polyisobutylene was analyzed by gel permeation chromatography under the following conditions, and the number average molecular weight (Mn) and the weight average molecular weight (Mw) were measured, and the molecular weight distribution (Mn) was calculated from the Mw/Mn.

-a column: PL MiniMixed B x 2

-a solvent: THF (tetrahydrofuran)

-flow rate: 0.3mL/min

-sample concentration: 2.0mg/mL

-injection amount: 10 μ l

Column temperature: 40 deg.C

-a detector: agilent RI detector

-standard: polystyrene (corrected by cubic function)

-data processing: ChemStation

[ Table 2]

All of the polyisobutenes of the examples were prepared using a catalyst composition according to the present invention comprising a catalyst represented by formula 1 and a nitrile additive. Specifically, in the examples, highly reactive polyisobutylene having a number average molecular weight of 1,000g/mol or more and an exo content of 90% or more was prepared, and the polymerization conversion rate was excellent.

Meanwhile, in the case of comparative examples 1 to 3 using a catalyst not corresponding to formula 1, and comparative example 8 using no additive in the catalyst composition, polyisobutylene having a small number average molecular weight and a broad molecular weight distribution was prepared, and in the case of comparative examples 4 to 7 using a compound other than nitrile as an additive, a polymerization reaction was not properly performed, and polyisobutylene was not obtained.

Experimental example 2

The examples and comparative examples were compared accordingly using the same reaction conditions and only differing in aging time. The method and conditions for measuring physical properties of polyisobutylene were the same as in experimental example 1.

[ Table 3]

	Polymerization conversion (%)	Appearance content (%)	Mn	MWD
					Example 1	94	90	1,530	1.9
Example 7	93	91	1,510	1.9
					Example 8	92	91	1,566	1.8
Example 9	94	90	1,500	1.9
					Comparative example 3	97	73	1,220	2.0
Comparative example 9	82	86	3,060	2.3
					Comparative example 10	45	90	4,953	2.4
Comparative example 11	20	92	5,730	2.3

As shown in table 3 above, the catalyst compositions according to the present invention can maintain a stable state for a long time, and polyisobutylene exhibiting a high number average molecular weight and exo content to a similar extent can be prepared in examples 7 to 9 using the catalyst compositions after storage at room temperature for a certain time after preparation. In contrast, when comparative example 3 and comparative examples 9 to 11 using comparative preparation example 3 as a catalyst were compared, the polymerization conversion rate rapidly decreased with the increase in storage time at room temperature. From this, it was confirmed that the catalyst composition used in the comparative example had poor stability at room temperature and the catalyst activity gradually decreased.

Experimental example 3

After polymerizing polyisobutylene according to example 1, example 2 and example 4 and comparative example 4, the polymerization solution was passed through a column packed with diatomaceous earth, silica, zeolite or glass fiber as shown in table 4 below.

With respect to example 1, example 2 and example 4, and comparative example 4, the product obtained after filtration through the above-described column and the polymerization solution without filtration were analyzed according to the following methods, and the results are shown in table 4.

(1) F content (wtppm)

Measurements were performed using a Combustion IC (ICS-2100/AQF-5000, Thermo Scientific Dionex) under the following conditions.

-a column: IonPac AS18 analytical (4X 250mm), IonPac AG18 guard (4X 50mm)

-eluent type: KOH (30.5mM)

-eluent flow rate: 1mL/min

-a detector: suppressed Conductivity Detector (Suppressed Conductivity Detector)

-SRS current: 76mA

-injection volume: 20 μ l

-isocratic/gradient conditions: equal degree

[ Table 4]

With example 1, example 2 and example 4, it was confirmed that if filtration was performed using a column including diatomaceous earth, silica and zeolite, a small amount of F element was detected when comparison was performed before the filtration was performed, and the catalyst was well removed. In contrast, with comparative example 4, the catalyst was hardly removed despite the filtration. Meanwhile, if a column including glass fibers is used, when F element is detected to almost the same degree as compared with the case where no filtration is performed, it can be confirmed that the glass fibers are not suitable.

As described above, it was found that if the catalyst composition according to the present invention is used, the catalyst remaining in the polyisobutylene can be easily removed by a simple method of filtering the polymerization product.