KR20220058063A - Method for producing polyisobutene - Google Patents

Abstract

The present invention relates to a method for manufacturing polyisobutene with improved productivity. The present invention relates to a method for manufacturing polyisobutene comprising the following steps: (S1) manufacturing a polymerization product by polymerizing isobutene at a pressure of 1 to 20 bar in the presence of a catalyst composition comprising a catalyst represented by chemical formula 1; and (S2) filtering the polymerization product to remove the catalyst.

Description

Method for producing polyisobutene

The present invention relates to a process for the production of polyisobutene.

Polyisobutene is divided into low molecular weight, medium molecular weight and high molecular weight ranges according to the molecular weight range. Low molecular weight polyisobutene refers to those having a number average molecular weight of 10,000 or less, and there are product groups of conventional polybutene and high reactive polybutene (HR-PB). The highly reactive polybutene has a carbon-carbon double bond mainly located at the end of the polybutene, and is used as a fuel additive or engine oil additive after introducing a functional group using a vinylidene functional group (>80%) at the terminal. .

In addition, polyisobutene having a medium molecular weight has a number average molecular weight of about 30,000 to 100,000 and is mainly used for adhesives, adhesives, sealants, waxes, etc. , can be used to improve ozone resistance.

Polyisobutene is generally prepared by polymerizing an olefin component having 4 carbon atoms derived from the decomposition process of naphtha using a Friedel-Craft type catalyst, and high-purity isobutene, C4 residual oil-1 ( C4 raffinate-1), butane-butene fraction (B-B fraction), etc. can be used as raw materials.

When high-purity isobutene is used as a raw material, a halogen-containing solvent such as methyl chloride or dichloromethane is mainly used as a polymerization solvent. Polyisobutene made in this way is widely used in fuel additives or lubricating oil. At this time, the residual halogen causes corrosion in the internal combustion engine and is discharged to cause environmental pollution.

In addition, when the C4 residual oil-1 remaining after 1,3-butadiene is extracted and the butane-butene fraction derived from the crude oil refining process are used as raw materials, a high content of halogen remains in the produced polyisobutene and isobutene oligomers. do. The C4 residual oil-1 and butane-butene fractions include isobutane, paraffins of normal butane, 1-butene, 2-butene, and 30 to 50 wt% Olefins such as isobutene are included, and the halogen content is high due to the influence of 1-butene.

In particular, when isobutene is not sufficiently polymerized when preparing polyisobutene, low molecular weight isobutene oligomers are produced as by-products. Since isobutene oligomers contain halogens, fuel additives, friction reducers, non-aromatic organic solvents, Since it is difficult to directly use it as a cosmetic additive, etc., it is separated and discarded or used only as low-cost fuel oil.

On the other hand, when halogen is removed through a separate process after isobutene oligomer is separated, its use becomes more diversified. Among the isobutene oligomers separated by fractional distillation after removal of halogen, organic substances having 8 to 20 carbon atoms can be used as non-aromatic organic solvents and alkylating agents, and organic substances having 24 or more carbon atoms have a large molecular weight and high degree, so they are used as fuel additives to reduce friction I can do my part. In addition, if the double bond in the organic material having 24 or more carbon atoms is removed by hydrogenation reaction, it is harmless and can be used in the human body, so that it can be used as a cosmetic additive.

However, since all of the above uses can be realized by removing the halogen contained in the isobutene oligomer, a post-treatment process of removing the halogen by contacting the isobutene oligomer with a solid such as an aluminum compound or zeolite after separating the isobutene oligomer is essential. do.

In addition, considering that isobutene oligomer is inevitably generated as a by-product when the purpose of manufacturing polyisobutene is used, these methods are designed to be used for other uses instead of discarding them, so in terms of manufacturing polyisobutene, The production of isobutene oligomers is still a situation inevitably affecting the yield or productivity of polyisobutene.

Korean Patent Registration No. 10-0486044

An object of the present invention is to improve the productivity of polyisobutene by preparing polyisobutene having excellent physical properties with high molecular weight and exo-content and reusable isobutene oligomer with low halogen content.

In order to solve the above problems, the present invention comprises the steps of (S1) preparing a polymerization product by polymerizing isobutene at a pressure of 1 to 20 bar in the presence of a catalyst composition comprising a catalyst represented by the following Chemical Formula 1; and (S2) filtering the polymerization product to remove the catalyst.

[Formula 1]

In Formula 1,

R is an alkyl group having 2 to 12 carbon atoms,

R ₁ to R ₄ are each independently hydrogen, a halogen group, or an alkyl group having 1 to 20 carbon atoms substituted with a halogen group,

o, p, q and r are each independently an integer from 1 to 5;

When the production method of the present invention is used, the halogen content of the isobutene oligomer produced as a by-product of isobutene polymerization is low. In this case, since the cationic polymerization can be further proceeded by separating the portion having a low number average molecular weight and adding it back to the polymerization process without separately removing the halogen, polyisobutene can be produced with better productivity using the same reactant.

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

The terms or words used in the description and claims of the present invention should not be construed as being limited to their ordinary or dictionary meanings, and the inventor appropriately defines the concept of the term in order to best describe his invention. Based on the principle that it can be done, it should be interpreted as meaning and concept consistent with the technical idea of the present invention.

The method for producing polyisobutene of the present invention comprises the steps of: (S1) preparing a polymerization product by polymerizing isobutene at a pressure of 1 to 20 bar in the presence of a catalyst composition comprising a catalyst represented by the following formula (1); and (S2) filtering the polymerization product to remove the catalyst.

In the present invention, the polyisobutene may include 20 wt% or less of an isobutene oligomer having a number average molecular weight of 300 to 500 g/mol based on polyisobutene, and the isobutene oligomer may have a halogen content of 20 wt ppm or less there is.

The "polyisobutene" refers to a polymer prepared by cationic polymerization of isobutene as a monomer, and an isobutene oligomer having a number average molecular weight of 300 to 500 g/mol, low molecular weight polyisobutene, and medium molecular weight polyisobu It may be composed of ten, high molecular weight polyisobutene, or the like.

The "isobutene oligomer" is formed by polymerization of isobutene, and isobutene, which does not normally participate in polymerization, is oligomerized such as dimerization and trimerization of isobutene, with 8 carbon atoms, 12 carbon atoms, 16 carbon atoms, 20 carbon atoms, It may be composed of a material having 24 carbon atoms, 28 carbon atoms, or the like. In particular, the isobutene oligomer in the present invention may have a number average molecular weight of 300 to 500 g/mol.

When polyisobutene is produced by polymerizing isobutene, if the polymer chain fails to grow into polyisobutene, an isobutene oligomer having a number average molecular weight of 300 to 500 g/mol is produced as a by-product. In particular, when isobutene is polymerized with a Friedel-Crafts catalyst (BF ₃ , etc.) that has been conventionally used for polyisobutene production, the isobutene oligomer produced as a by-product contains hundreds of organic halogens derived from the Friedel-Crafts-type catalyst. to several thousand ppm by weight. In this case, the isobutene oligomer is difficult to use for other purposes due to halogen, and has been considered only as a by-product without commercial value.

In addition, halogen is also detected in the produced polyisobutene. The halogen dissociated from the catalyst used for polymerization is bound to the end of the polyisobutene, or the catalyst is not efficiently removed after the polymerization is completed. This is because it remains in isobutene. Halogen in polyisobutene can cause toxicity, and when a halogen atom is bonded to the terminal double bond of polyisobutene, the exo-content of polyisobutene decreases and the quality deteriorates even to reactivity.

On the other hand, when the production method of the present invention is used, cationic polymerization of isobutene proceeds efficiently, so that the content of isobutene oligomer in polyisobutene is low, and therefore polyisobutene having a high molecular weight and a narrow molecular weight distribution can be produced. In addition, since the polyisobutene contains less halogen, it is possible to prevent the above-described problems derived from halogen.

In addition, when only the isobutene oligomer is separated from polyisobutene, since the halogen content of the isobutene oligomer itself is low and the exo-content is high, it is possible to cationically polymerize the isobutene oligomer with isobutene again to grow it into polyisobutene. .

Hereinafter, each step will be described in detail.

Step (S1)

The step (S1) is a step of preparing a polymerization product by polymerizing isobutene at a pressure of 1 to 20 bar in the presence of a catalyst composition including a catalyst represented by the following formula (1).

[Formula 1]

In Formula 1,

R is an alkyl group having 2 to 12 carbon atoms,

R ₁ to R ₄ are each independently hydrogen, a halogen group, or an alkyl group having 1 to 20 carbon atoms substituted with a halogen group,

o, p, q and r are each independently an integer from 1 to 5;

The "alkyl group" may mean a monovalent aliphatic saturated hydrocarbon, and linear alkyl groups such as methyl, ethyl, propyl and butyl and isopropyl, sec-butyl, tert-butyl ( It may mean including all branched alkyl groups such as tert-butyl) and neopentyl (neo-pentyl). Specifically, methyl group, ethyl group, propyl group, isopropyl group, butyl group, isobutyl group, tert-butyl group, sec-butyl group, 1-methyl-butyl group, 1-ethyl-butyl group, pentyl group, isopen Tyl group, neopentyl group, tert-pentyl group, 1-methylpentyl group, 2-methylpentyl group, 4-methyl-2-pentyl group, hexyl group, isohexyl group, 4-methylhexyl group, 5-methylhexyl group , a heptyl group, and the like, but is not limited thereto.

The catalyst of the present invention has a strong C-B bond because it contains an organic borate containing at least one phenyl group having at least one phenyl group having a strong electron-attracting phenomenon, and thus has a strong C-B bond, and can be used for cationic polymerization to exhibit excellent efficiency.

In addition, when a catalyst that does not correspond to Formula 1, such as a Lewis acid catalyst, is used, a large amount of an organic base such as NaOH, KOH, NaNH ₄ , KNH ₄ is used for quenching after the reaction, these organic bases are It reacts with the Lewis acid to produce highly toxic wastes such as Na(BF ₃ OH), Na(AlCl ₃ OH), K(BF ₃ OH), and K(AlCl ₃ OH), and when it is washed, a large amount of wastewater is generated.

In Formula 1, R is an alkyl group having 2 to 12 carbon atoms, specifically, an alkyl group having 2 to 8 carbon atoms, an alkyl group having 2 to 6 carbon atoms, an alkyl group having 2 to 4 carbon atoms, preferably an ethyl group or a butyl group.

In Formula 1, R ₁ to R ₄ are each independently hydrogen, a halogen group, or an alkyl group having 1 to 20 carbon atoms substituted with a halogen group, specifically a halogen group, and may be F or Cl, for example, R ₁ to R ₄ may all be F. In addition, 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, R ₁ to R ₄ may be F and o, p, q and r may be 5.

는 구체적으로 테트라키스(페닐)보레이트, 테트라키스(펜타플루오로페닐)보레이트, 테트라키스[3,5-비스(트리플루오로메틸)페닐]보레이트 및 그 유도체로 이루어진 군으로부터 선택되는 1종 이상일 수 있고, 바람직하게는 테트라키스(펜타플루오로페닐)보레이트일 수 있다.In addition, the organic borate contained in the compound represented by Formula 1

Specifically, tetrakis(phenyl)borate, tetrakis(pentafluorophenyl)borate, tetrakis[3,5-bis(trifluoromethyl)phenyl]borate, and derivatives thereof may be at least one selected from the group consisting of and preferably tetrakis (pentafluorophenyl) borate.

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

[Formula 1-1]

[Formula 1-2]

In the present invention, since the catalyst represented by Formula 1 is easily removed by a filtration method as described later, the risk of dissociation of halogen from the catalyst is efficiently and fundamentally prevented, so that the halogen content of the isobutene oligomer can be further reduced. do.

In addition, the catalyst represented by Formula 1 has a stabilized structure in which halogen contained in the anion portion is substituted with phenyl, and is not easily dissociated. Therefore, it is unlikely that the dissociated halogen will be bound to the terminal of the isobutene oligomer, and an isobutene oligomer containing less than 20 ppm by weight of halogen is formed.

On the other hand, in a catalyst having a structure in which halogen atoms form a weak bond in the catalyst, such as not including a phenyl group in the anion portion, the halogen in the catalyst is easily dissociated during polymerization, and this may be bonded to the end of the chain during cationic polymerization. In this case, an isobutene oligomer having a halogen bonded to the terminal is formed, which is a structure that can no longer participate in the polymerization reaction, so there is no possibility of further cationic polymerization with isobutene to grow into polyisobutene. Therefore, the isobutene oligomer containing a halogen content of more than 20 ppm by weight is separated, and since it cannot be reused, the efficiency of polyisobutene production is lowered.

In the present invention, the isobutene oligomer having a number average molecular weight of 300 to 500 g/mol may be 20 wt% or less based on polyisobutene, specifically 1.0 wt% or more, 2.0 wt% or more, 2.5 wt% based on polyisobutene or more, 3.0 wt% or more, 20.0 wt% or less, 15.0 wt% or less, 10.0 wt% or less, 5.0 wt% or less.

When the isobutene oligomer is more than 20 wt% based on polyisobutene, input costs and equipment for separation and recovery thereof increase. In this case, it is difficult to realize the object of the present invention to improve productivity by separating and recovering the isobutene oligomer produced as a by-product and using it again for the production of polyisobutene, as well as the molecular weight and viscosity of the produced polyisobutene itself. is too low and non-uniform, which may lead to deterioration of the physical properties of the product.

In addition, the isobutene oligomer may have a halogen content of 20 weight ppm or less based on the isobutene oligomer, and specifically, 15 weight ppm or less and 10 weight ppm or less. According to the manufacturing method of the present invention, since the by-product isobutene oligomer contains a small amount of halogen as described above, polyisobutene can be efficiently prepared by separating it and performing additional cationic polymerization with isobutene.

In addition, the exo-content of the isobutene oligomer may be 50 to 99%, such as 50% or more, 60% or more, 70% or more, 80% or more, 85% or more, 90% or more, 99% or less.

In the present invention, the polymerization of isobutene is carried out at a pressure of 1 to 20 bar, specifically at a pressure of 1 to 10 bar, such as 1.0 bar or more, 20.0 bar or less, 10.0 bar or less, 7.0 bar or less, 5.0 bar or less. can be performed.

When the polymerization pressure is less than 1 bar, liquefaction is not smooth in the process of dissolving isobutene in a solvent after gas is introduced in the preparation of polyisobutene, so the polymerization conversion rate is low, and the yield of polyisobutene may be lowered, and it may participate in the polymerization Only polyisobutene having a low number average molecular weight can be produced because there are few possible isobutenes.

In addition, since chain growth proceeds slowly, the isobutene oligomer is contained in an amount of more than 20% by weight based on polyisobutene, and when a large amount of isobutene oligomer is generated, the input cost and equipment for separating and recovering the isobutene oligomer increases. In this case, it is difficult to realize the object of the present invention to improve productivity by separating and recovering the isobutene oligomer produced as a by-product and using it again for the production of polyisobutene, as well as the molecular weight and viscosity of the produced polyisobutene itself. is too low and non-uniform, which may lead to deterioration of the physical properties of the product.

In the present invention, the polymerization of isobutene may be carried out at a temperature of 0 to 50° C., and exo-content, that is, the content of terminal carbon-carbon double bonds while preparing the high molecular weight polyisobutene targeted in the present invention In terms of making it appear high, specifically, 0 °C or higher, 10 °C or higher, 15 °C or higher, 20 °C or higher, 25 °C or higher, 50 °C or lower, 45 °C or lower, 40 °C or lower, 35 °C or lower, such as 30 °C can be carried out at a temperature of

When the polymerization temperature is less than 0 ℃, the catalyst activity is reduced due to the low temperature, the polymerization conversion rate is lowered or a problem that a more catalyst is required may appear, and when the polymerization temperature is more than 50 ℃, the chain transfer occurs too quickly However, polyisobutene having a low molecular weight may be produced, or the exo-content may be lowered, resulting in deterioration of the quality of polyisobutene.

In addition, while satisfying the above temperature conditions, the polymerization may be carried out for 10 minutes to 3 hours, specifically 30 minutes or more, 1 hour or more, 1.5 hours or more, 3 hours or less, 2.5 hours or less, such as 2 hours can be performed while

In the present invention, the catalyst represented by Formula 1 may be 5 to 150 wt ppm based on isobutene, specifically, 5 wt ppm or more, 10 wt ppm or more, 15 wt ppm or more, 150 wt ppm or less, 100 wt ppm or less, 80 wt ppm or less, 50 wt ppm or less, 30 wt ppm or less, such as 20 wt ppm.

When the catalyst represented by the formula (1) is less than 5 ppm by weight based on isobutene, cationic polymerization does not proceed smoothly due to insufficient catalyst amount compared to isobutene, and a problem of low polymerization conversion or reduced production may appear, and the When the catalyst represented by Formula 1 is more than 150 weight ppm based on isobutene, the polymerization conversion does not improve compared to the increase in the amount of catalyst, so economic feasibility is rather deteriorated, or polymerization of isobutene occurs due to the excessive amount of catalyst, so that the isobutene oligomer A large amount of is formed and there may be a problem in that polyisobutene having a low exo-content or molecular weight is obtained.

In the present invention, the catalyst composition may further include a co-catalyst to control the physical properties of polyisobutene, and in this case, the co-catalyst may be any co-catalyst in the art applicable to polyisobutene production without limitation. there is.

Step (S2)

The catalyst is removed by filtering the polymerization product obtained in step (S1). Specifically, the catalyst represented by Formula 1 remaining in the polymerization product after polymerization of isobutene is removed.

Since the catalyst represented by Formula 1 used in the present invention can be efficiently removed through a physical step of simple filtration, it is much easier to use and remove than the conventionally used Lewis acid catalyst. In addition, by removing the catalyst through the filtration to remove halogen that may be derived from the catalyst in advance, polyisobutene having a low halogen content can be obtained from the polymerization product.

Specifically, the polyisobutene may have a halogen content of 20 weight ppm or less based on polyisobutene, and specifically 15 weight ppm or less and 10 weight ppm or less.

In the present invention, the filtration may be performed using a filter having a diameter of 3 to 50 mm, and specifically, a filter having a diameter of 3 mm or more, 6 mm or more, 40 mm or less, 30 mm or less may be used. , but not limited thereto.

In the present invention, the filter may be made of at least one material selected from the group consisting of silica, celite, zeolite, glass and aluminum oxide, and preferably may be made of silica, but is not limited thereto.

In addition, when the fluidity of the polymerization product is low, if necessary, an organic solvent such as pentane, cyclopentane, hexane, cyclohexane, heptane, octane, diethyl ether, and petroleum ether using at least one selected from the group consisting of After imparting fluidity, the filtration may be performed.

Typically, the resulting polyisobutene is dissolved in an organic solvent and then washed with water to remove the residual catalyst, but in the present invention, the catalyst represented by Formula 1 can be efficiently removed through a simple filtration step as described above. The washing step may not be performed.

In the present invention, the isobutene oligomer contained in polyisobutene may be separated by distilling polyisobutene under reduced pressure at a temperature of 200 to 280° C. and a pressure of less than 250 torr. The vacuum distillation may be performed using, for example, a rotary evaporator.

In addition, prior to separation of the isobutene oligomer through the vacuum distillation, the step of removing unreacted isobutene and the solvent may be performed first. Specifically, after removing unreacted isobutene by venting at room temperature and under normal pressure, the solvent may be removed by heating to a temperature equal to or higher than the boiling point of the solvent.

Preferably, after removing the catalyst by filtration of the polymerization product in step (S2), venting at room temperature and pressure to remove unreacted isobutene and then heating to remove the solvent, and then using a rotary evaporator at 200 to 280 ° C. By vacuum distillation at a temperature and a pressure of less than 250 torr, an isobutene oligomer having a halogen content of 20 wt ppm or less and a number average molecular weight of 300 to 500 g/mol can be separated from polyisobutene.

As described above, the polyisobutene prepared according to the present invention contains less isobutene oligomers having a number average molecular weight of 300 to 500 g/mol, and thus may have a high molecular weight and a narrow molecular weight distribution.

Specifically, the number average molecular weight of the polyisobutene prepared according to the present invention may be 1,000 to 10,000 g/mol, and specifically, 1,000 g/mol or more, 1,200 g/mol or more, 1,300 g/mol or more, 1,400 g/mol or more. mol or more, 10,000 g/mol or less, 5,000 g/mol or less, 4,500 g/mol or less, 4,000 g/mol or less, 3,000 g/mol or less, 2,000 g/mol or less.

In addition, the molecular weight distribution of the polyisobutene may be 1.5 to 3.0, specifically 1.5 or more, 3.0 or less, 2.5 or less, 2.3 or less, 2.1 or less.

The weight average molecular weight and the number average molecular weight are polystyrene equivalent molecular weights analyzed by gel permeation chromatography (GPC), and the molecular weight distribution is calculated from the ratio of (weight average molecular weight)/(number average molecular weight).

In addition, the exo-content of the polyisobutene may be 50 to 99%, such as 50% or more, 60% or more, 70% or more, 80% or more, 85% or more, 99% or less, 95% or less.

Example

Hereinafter, the present invention will be described in more detail by way of Examples. However, the following examples are provided to illustrate the present invention, and the scope of the present invention is not limited thereto.

Preparation Example 1

[Formula 1-1]

In a glove box, 1 g of [H(Et ₂ O) ₂ ][B(C ₆ F ₅ ) ₄ ] was placed in a round flask, and 10 mL of dichloromethane was added thereto. At room temperature, 5 equivalents of anhydrous dibutyl ether (Sigma-Aldrich) was added and stirred for 30 minutes. After stirring, all solvents were removed under vacuum conditions. The obtained white powder was washed 5mL × 3 times with anhydrous hexane, and then dried again under vacuum conditions to obtain [H(nBu ₂ O) ₂ ][B(C ₆ F ₅ ) ₄ ].

Preparation 2

[Formula 1-2]

In a glove box under argon conditions, 1 g of [Li(Et ₂ O) _n ][B(C ₆ F ₅ ) ₄ ] (TCI Corporation) was placed in a round flask, and 10 mL of anhydrous diehtyl ether was added. . The prepared solution was brought out to the glove box foil and then connected to a Schlenk line to set the argon condition. A cooling bath was made using acetonitrile and dry ice, and the prepared solution was stirred at -40°C. 5 equivalents of 1M HCl (TCI) in diethyl ether was injected into the stirred solution through a syringe. After further stirring at -40°C for 30 minutes, the temperature was slowly raised to room temperature. The solution that had come to room temperature was brought back into the glove box, the resulting salt was removed through a filter, and only the transparent solution was collected and dried under vacuum conditions. All solvents were vacuum dried, washed with anhydrous hexane 5mL × 3 times, and then vacuum dried to obtain [H(Et ₂ O) ₂ ][B(C ₆ F ₅ ) ₄ ].

Example 1

An isobutene line was connected to an Andrew glass flask in a vacuum state cooled at 10° C. or less, and 20 g of isobutene was added. At the same temperature, 80 mL of a toluene solvent was injected using a syringe.

Thereafter, the Andrew glass flask was maintained at a polymerization temperature of 30° C. and a polymerization pressure of 3 bar. In a glove box, the catalyst of Preparation Example 1 was quantified at 20 ppm by weight based on isobutene, prepared by dissolving in 0.5 mL DCM, and then injected using a syringe. Cationic polymerization of isobutene was carried out for 2 hours.

After that, the polymerization product is put into silica having a diameter of 3 to 50 mm as it is, and the catalyst is removed by filtration, and then unreacted isobutene is removed by venting at room temperature and pressure, and then toluene is removed through heating to obtain polyisobutene. obtained.

Example 2

Polyisobutene was prepared in the same manner as in Example 1, except that the catalyst of Preparation Example 2 was used instead of the catalyst of Preparation Example 1.

Example 3

Polyisobutene was prepared in the same manner as in Example 1, except that the polymerization pressure of isobutene was changed to 1 bar.

Example 4

Polyisobutene was prepared in the same manner as in Example 1, except that the polymerization pressure of isobutene was changed to 5 bar.

Comparative Example 1

It was prepared in the same manner as in Example 1, except that the process of filtering the polymerization product into silica was omitted.

Comparative Example 2

It was prepared in the same manner as in Example 1, except that an isopropanol-BF ₃ complex catalyst was used instead of the catalyst of Preparation Example 1 and the polymerization temperature was changed to -20°C.

Comparative Example 3

It was prepared in the same manner as in Example 1, except that an isopropanol-BF ₃ complex catalyst was used instead of the catalyst of Preparation Example 1.

Comparative Example 4

Except for changing the polymerization pressure of isobutene to 0 bar, it was prepared in the same manner as in Example 1.

Experimental Example 1

For the polyisobutene obtained in Examples and Comparative Examples, physical properties were measured according to the following method.

(1) Number average molecular weight (Mn) and molecular weight distribution (MWD)

Polyisobutene was analyzed by gel permeation chromatography under the following conditions to measure a number average molecular weight (Mn) and a weight average molecular weight (Mw), and a molecular weight distribution (Mn) was calculated as Mw/Mn.

- Column: PL MiniMixed B × 2

- Solvent: THF

- Flow rate: 0.3 mL/min

- Sample concentration: 2.0 mg/mL

- Injection volume: 10 μL

- Column temperature: 40℃

- Detector: Agilent RI detector

- Standard: Polystyrene (corrected by cubic function)

- Data processing: ChemStation

(2) exo-content (%)

¹ H NMR measurement was performed using Varian 500 MHz NMR to confirm the form of exo-olefin and endo-olefin according to the position of the double bond, and the exo-content (%) was calculated by the following formula:

- exo-content (%) = (number of moles of exo-olefin with carbon-carbon double bond at the terminal)/(number of moles of exo-olefin and endo-olefin produced) × 100

(3) F content (weight ppm)

It was measured by analytical combustion IC (ICS-5000/AQF-2100H).

Yield (g) Mn (g/mol) MWD exo-content (%) F content (ppm by weight) Example 1 19.2 1,525 1.8 90 < 10 Example 2 19.2 1,623 1.8 90 < 10 Example 3 18.6 1,453 1.7 91 < 10 Example 4 19.1 1,766 1.8 91 < 10 Comparative Example 1 19.3 1,578 1.7 85 48 Comparative Example 2 16.3 1,616 1.7 92 35 Comparative Example 3 19.8 412 3.9 35 400-500 Comparative Example 4 13.2 841 1.5 90 < 10

As shown in Table 1, according to the manufacturing method of the present invention, polyisobutene can be prepared in an excellent yield. In addition, it was confirmed that the prepared polyisobutene had high molecular weight and high exo-content and low halogen content, so that the quality was excellent.

On the other hand, in Comparative Example 1 in which the polymerization product was not filtered, polyisobutene having a high halogen content was prepared due to the residual catalyst. In Comparative Examples 2 and 3, a conventional catalyst that does not correspond to Formula 1 was used. Unlike the catalyst of the present invention, the catalyst is not easily removed by simple filtration, so it still remains in the polymer, and as a result, polyisobutene is Halogen content was significantly increased. In particular, in Comparative Example 3, the halogen content was very high and the number average molecular weight was also low at a level of 300 to 500 g/mol, indicating that polyisobutene was not produced but only isobutene oligomer having a low molecular weight region was prepared . In Comparative Example 4, since polymerization was performed at a low pressure of less than 1 bar, the polymerization of isobutene did not proceed smoothly, so the yield of polyisobutene was lowered, and a lot of isobutene oligomers in polyisobutene were generated, resulting in a number average molecular weight. was confirmed to be lowered.

Experimental Example 2

The polyisobutene obtained in Examples and Comparative Examples was subjected to vacuum distillation at a temperature of 200 to 280° C. and a pressure of less than 250 torr using a rotary evaporator to separate isobutene oligomers.

The physical properties of the isobutene oligomer obtained above were measured according to the following method. In the case of Comparative Example 3, the obtained product was excluded because it corresponds to the region of the isobutene oligomer.

(1) Content of isobutene oligomer (% by weight)

According to the following formula, the ratio of isobutene oligomer included in polyisobutene was calculated.

- Content of isobutene oligomer (wt%) = [(weight of isobutene oligomer)/(weight of polyisobutene before separation of isobutene oligomer)] × 100

(2) number average molecular weight (Mn) and molecular weight distribution (MWD)

The isobutene oligomer was analyzed by gel permeation chromatography under the following conditions to measure the number average molecular weight (Mn) and the weight average molecular weight (Mw), and the molecular weight distribution (Mn) was calculated as Mw/Mn.

- Column: PL MiniMixed B × 2

- Solvent: THF

- Flow rate: 0.3 mL/min

- Sample concentration: 2.0 mg/mL

- Injection volume: 10 μL

- Column temperature: 40℃

- Detector: Agilent RI detector

- Standard: Polystyrene (corrected by cubic function)

- Data processing: ChemStation

(3) exo-content (%)

¹ H NMR measurement was performed using Varian 500 MHz NMR to confirm the form of exo-olefin and endo-olefin according to the position of the double bond, and the exo-content (%) was calculated by the following formula:

- exo-content (%) = [(number of moles of exo-olefin with carbon-carbon double bond at the terminal)/(number of moles of exo-olefin and endo-olefin produced)] × 100

(4) F content in isobutene oligomer (ppm by weight)

It was measured by analytical combustion IC (ICS-5000/AQF-2100H).

Content of isobutene oligomer (% by weight) Mn (g/mol) MWD exo-content (%) F content (ppm by weight) Example 1 3.9 372 1.0 95 < 10 Example 2 3.6 373 1.1 96 < 10 Example 3 3.2 412 1.1 94 < 10 Example 4 3.5 311 1.0 96 < 10 Comparative Example 1 3.9 495 1.2 93 < 10 Comparative Example 2 5.4 354 1.1 34 200-300 Comparative Example 4 27 193 1.6 93 < 10

As can be seen from Table 2, when the manufacturing method according to the present invention was used, the content of isobutene oligomer in polyisobutene was small, and the isolated isobutene oligomer had a low halogen content and a high exo-content.

On the other hand, in Comparative Example 2 using a conventional catalyst that does not correspond to Formula 1, an isobutene oligomer having a low exo-content and a high halogen content was prepared, and in Comparative Example 4, the isobutene oligomer was polyisobutene due to the low polymerization pressure. It was found that a large amount was included in excess of 20 wt% based on ten.

Experimental Example 3

In Experimental Example 2, it was confirmed whether the isobutene oligomer isolated from Example 1 or Comparative Example 2 could be further used for cationic polymerization with isobutene by the following method.

(1) Polymerization conditions-(a)

Polyisobutene was prepared in the same manner as in Example 1, except that 5 g of the isobutene oligomer separated from Example 1 or Comparative Example 2 and 15 g of isobutene were used instead of 20 g of isobutene.

(2) Polymerization conditions-(b)

Polyisobutene was prepared in the same manner as in Example 1, except that 10 g of the isobutene oligomer and 10 g of isobutene isolated from Example 1 or Comparative Example 2 were used instead of 20 g of isobutene.

Yield (g) Mn MWD exo-content (%) Example 1-(a) 18.8 1,619 1.8 89 Example 1-(b) 18.3 1,591 1.9 90 Comparative Example 2-(a) 13.2 1,007 2.5 63 Comparative Example 2-(b) 8.8 847 2.7 45

As shown in Table 3, the isobutene oligomer separated as a by-product after preparing polyisobutene according to the manufacturing method of the present invention can be cationic polymerized with isobutene again, and as a result of polymerization, a high molecular weight with a narrow molecular weight distribution. Polyisobutene could be produced.

On the other hand, the isobutene oligomer separated in Comparative Example 2 had a very high F content, and when it was polymerized with isobutene, the polymerization efficiency was low, so that the yield of polyisobutene was reduced compared to the Example, and the prepared polyisobutene had a molecular weight It was confirmed that physical properties decreased, the molecular weight distribution was widened, and the exo-content was lowered.

As described above, according to the production method of the present invention, polyisobutene having excellent physical properties with high molecular weight and exo-content and low halogen content can be prepared, and the halogen content of the isobutene oligomer obtained as a by-product is also low. After separation of the isobutene oligomer, polyisobutene may be further prepared by polymerization with isobutene again.

Claims (12)

(S1) preparing a polymerization product by polymerizing isobutene at a pressure of 1 to 20 bar in the presence of a catalyst composition comprising a catalyst represented by the following Chemical Formula 1; and
(S2) filtering the polymerization product to remove the catalyst; Method for producing polyisobutene comprising:
[Formula 1]

In Formula 1,
R is an alkyl group having 2 to 12 carbon atoms,
R ₁ to R ₄ are each independently hydrogen, a halogen group, or an alkyl group having 1 to 20 carbon atoms substituted with a halogen group,
o, p, q and r are each independently an integer of 1 to 5;
The method according to claim 1,
The polymerization of step (S1) is a method for producing polyisobutene is carried out at a pressure of 1 to 10 bar.
The method according to claim 1,
The method for producing polyisobutene, wherein the polyisobutene contains 20 wt% or less of an isobutene oligomer having a number average molecular weight of 300 to 500 g/mol based on polyisobutene.
4. The method according to claim 3,
The isobutene oligomer is a method for producing polyisobutene, wherein the halogen content is 20 ppm by weight or less based on the isobutene oligomer.
The method according to claim 1,
The polymerization of step (S1) is a method for producing polyisobutene is carried out at a temperature of 0 to 50 ℃.
The method according to claim 1,
The filtration of the step (S2) is a method for producing polyisobutene that is performed using a filter having a diameter of 3 to 50 mm.
The method according to claim 1,
In Formula 1,
R is an alkyl group having 2 to 8 carbon atoms,
R ₁ to R ₄ are each independently a halogen group,
o, p, q and r are each independently an integer of 3 to 5. A method for producing polyisobutene.
The method according to claim 1,
In Formula 1,
R is an alkyl group having 2 to 6 carbon atoms,
R ₁ to R ₄ are each independently F or Cl,
o, p, q and r are each independently an integer of 4 or 5 for producing polyisobutene.
The method according to claim 1,
The catalyst represented by Formula 1 is a method for producing polyisobutene in an amount of 5 to 150 ppm by weight based on isobutene.
The method according to claim 1,
The polyisobutene is a method for producing polyisobutene having a halogen content of 20 ppm by weight or less based on polyisobutene.
The method according to claim 1,
A method for producing polyisobutene, wherein the number average molecular weight of the polyisobutene is 1,000 to 10,000 g/mol.
The method according to claim 1,
The molecular weight distribution of the polyisobutene is 1.5 to 3.0 of the method for producing polyisobutene.