JP2018154788A - Method for producing isobutylene-based polymer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for producing an isobutylene-based polymer having a small molecular distribution and a high content of halogen atoms remaining in the polymer terminal, by suppressing side reactions.SOLUTION: There is provided a method for producing an isobutylene-based polymer by living cationic polymerization in the coexistence of a polymerization initiator, a polymerization catalyst, and a saturated cyclic ether type compound, where the saturated cyclic ether type compound is a 6-or more membered ring compound having only one oxygen atom in the ring. There is provided a method for producing an isobutylene-based polymer, where the isobutylene-based polymer has a molecular weight distribution (Mw/Mn) of 1.00 to 1.37 and contains 96.0 mol% or more of a leaving group (halogen atom) derived from the polymerization initiator.SELECTED DRAWING: None

Description

  The present invention provides a method for obtaining an isobutylene polymer having a small molecular weight distribution Mw / Mn and suppressing side reactions at the polymer terminals.

  It is known that the polymerization of isobutylene proceeds by cationic polymerization. As an example of such cationic polymerization, a so-called inifer method is known in which a compound having a halogen group bonded to a tertiary carbon such as dicumyl chloride is used as a polymerization initiator in the presence of a Lewis acid catalyst. . According to this method, living cationic polymerization of isobutylene is possible, and the molecular weight of the resulting isobutylene polymer is determined by the molar ratio of the polymerization initiator and the monomer, so that it is possible to design a molecule according to the application.

  The isobutylene polymer obtained by living cationic polymerization can introduce a reactive group at the end of the molecular chain or bind a styrene polymer block. Therefore, the isobutylene-based polymer obtained by these methods is suitable for use as a reactive curable liquid resin in various sealants, adhesives, adhesives, etc., and as a thermoplastic elastomer, suitable for various rubber materials. Has been used.

  At this time, whether or not the physical properties of the resulting isobutylene polymer are industrially superior depends on the reactive group introduced at the end of the molecular chain and the introduction rate of the block copolymer segment. Specifically, it is preferable that these are introduced quantitatively at the molecular chain ends.

  However, in cationic polymerization, it is known that the terminal of the growing polymer has a thermally unstable carbocation structure and is deactivated by various side reactions. Since it becomes impossible to introduce the reactive group or block copolymer segment as described above into the deactivated polymer terminal, usually, an attempt is made to avoid deactivation of the polymer terminal and maintain the reactivity.

  As a technique for maintaining the reactivity of such a polymer terminal, for example, as described in Patent Documents 1 to 9, methods using various electron donor components are known.

Japanese Patent Laid-Open No. 1-318014 JP-A-2-245004 JP-A-3-174403 JP 2002-348317 A JP 2009-126889 A JP-T-2006-501306 Special table 2015-531424 gazette Special table 2015-507069 gazette JP-T-2004-525197

  As a living cationic polymerization method for isobutylene, a polymerization initiator system comprising a combination of a Lewis catalyst and various electron donor components has been developed. For example, a combination of a titanium tetrachloride catalyst and an ester, amide, or amine can be mentioned, but satisfactory polymerization control has not always been possible.

  As described in Patent Documents 1 to 3, the use of amine-based additives such as pyridines and trialkylamines is a standard method of isobutylene living cationic polymerization, but traps protons in the system. The amine / hydrogen chloride salt produced later is often insoluble in a commonly used polymerization solvent and remains in the polymerization machine as a precipitate. This is a problem that must be avoided, particularly in the continuous polymerization method, because it causes piping blockage and leads to unstable production.

  Moreover, as described in Patent Document 4, living cationic polymerization of isobutylene in which an ether compound coexists in a polymerization system is known. However, as a result of the study by the present inventors, among ether compounds, a chain ether compound has a greater effect of inducing a chain transfer reaction or a coupling reaction between polymer chains, rather than an effect of stabilizing the polymerization. It has been found that it does not act as a stabilizer for cationic polymerization.

  On the other hand, an example using a cyclic ether compound such as tetrahydrofuran is disclosed. In this case, it can be seen that the effect of controlling the polymerization reaction is insufficient because the value of the molecular weight distribution is smaller when tetrahydrofuran is not added. In addition, since the number of vinyl groups (Fn (vinyl)) introduced at the end of the isobutylene polymer exceeds 2.0, this polymerization system completely eliminates side reactions derived from moisture and proton sources in the system. It is also clear that it is not possible to control.

  As disclosed in Patent Document 5, together with a chain ether compound such as n-butyl ether and a cyclic ether compound such as tetrahydrofuran, the polymer terminal of the isobutylene polymer obtained by living cationic polymerization is deactivated, It has been reported that it has the property of being induced to an isopropenyl group. This utilizes a property opposite to the viewpoint of maintaining the living property of the polymerization system. Furthermore, it has been reported that a cyclic ether having two oxygen atoms in the ring such as 1,3-dioxolane has a high induction rate to an isopropenyl group. For this reason, in the living cationic polymerization, knowledge about the effect of suppressing the side reaction by the ether compound is insufficient, and in particular, the property of the cyclic ether compound has room for further study.

  Furthermore, as described in Patent Documents 6 to 9, it has been known to use tetrahydrofuran in the cationic polymerization of isobutylene.

  In general, tetrahydrofuran is miscible with water at an arbitrary ratio, which makes it difficult to recover in the production process of the isobutylene polymer, resulting in problems such as deterioration of water quality of factory waste water and increase of environmental load.

  Thus, there was room for further improvement in the selection of the electron donor component that can be suitably used for the living cationic polymerization of isobutylene. In particular, ether compounds are preferred as polymerization stabilizers in that they do not form precipitates with hydrogen chloride present in the system, but there is room for further study in selecting them.

  Accordingly, an object of the present invention is to provide an isobutylene polymer having a small molecular weight distribution, a high content of halogen atoms remaining at the polymer terminal, and suitable for obtaining a functionalized isobutylene polymer or an isobutylene block copolymer. It is to provide a manufacturing method.

As a result of extensive studies to achieve the above object, the present inventor has found that the above object can be achieved by polymerizing isobutylene in the presence of a specific cyclic ether. That is, the present invention
(1) A method for producing an isobutylene polymer by living cationic polymerization in the presence of a polymerization initiator, a polymerization catalyst, and a saturated cyclic ether compound, wherein the saturated cyclic ether compound contains an oxygen atom in the ring. The present invention relates to a process for producing an isobutylene polymer, which is a compound having only one 6-membered ring.

  (2) The present invention relates to a method for producing an isobutylene polymer, wherein the molecular weight distribution (Mw / Mn) of the isobutylene polymer is 1.00 to 1.37.

  (3) The present invention relates to a method for producing an isobutylene polymer, wherein the isobutylene polymer contains 96.0 mol% or more of a leaving group derived from the polymerization initiator.

(4) The present invention relates to a method for producing an isobutylene polymer, characterized in that the saturated cyclic ether compound is allowed to coexist at a concentration of 1.00 × 10 ⁻⁴ to 1.00 mol / L.

  (5) The saturated cyclic ether compound is at least one selected from the group consisting of tetrahydropyran, 2-methyltetrahydropyran, 4-methyltetrahydropyran, 2,2-dimethyltetrahydropyran, and hexamethylene oxide. The present invention relates to a process for producing an isobutylene polymer.

  According to the production method of the present invention, it is possible to obtain an isobutylene polymer in which side reactions during polymerization are suppressed, the molecular weight distribution Mw / Mn is small, and the content of leaving groups remaining at the polymer ends is high. . Such an isobutylene polymer is preferable because the number of functional groups introduced per molecule can be increased and a good physical property can be exhibited when a terminal functionalization reaction is further performed. On the other hand, by using a block copolymer with an aromatic vinyl compound such as styrene, a thermoplastic elastomer can be obtained, but a polymer excellent in rubber physical properties of the obtained thermoplastic elastomer can be obtained. Is preferable.

  The present invention is a process for producing an isobutylene polymer by living cationic polymerization in the presence of a polymerization initiator, a polymerization catalyst, and a saturated cyclic ether compound, wherein the saturated cyclic ether compound is an oxygen atom in the ring. This is a method for producing an isobutylene polymer, characterized in that it is a compound of 6-membered ring or more having only one.

  In the present invention, as the monomer constituting the isobutylene polymer, other than the primary use of isobutylene, other cationic polymerizable monomers may be copolymerized as long as the effects of the present invention are not impaired.

  Examples of such monomers include olefins having 4 to 12 carbon atoms, vinyl ethers, aromatic vinyl compounds, vinyl silanes, and allyl silanes. Specifically, isoprene, amylene, 1,3-butadiene, 1-butene, 2-butene, 2-methyl-1-butene, 3-methyl-1-butene, pentene, 4-methyl-1-pentene, hexene, vinylcyclohexene, α-pinene, β-pinene , Limonene, styrene, indene, α-methylstyrene, methoxystyrene, methylstyrene, trimethylstyrene, chlorostyrene, dichlorostyrene, methyl vinyl ether, ethyl vinyl ether, isobutyl vinyl ether, vinyl trichlorosilane, vinylmethyldichlorosilane, vinyldimethylchlorosilane, vinyl Dimethylmethoxysilane, vinyltrimethylsilane, divinyldichlorosilane, divinyldimethoxysilane, divinyldimethylsilane, 1,3-divinyl-1,1,3,3- List tramethyldisiloxane, trivinylmethylsilane, tetravinylsilane, allyltrichlorosilane, allylmethyldichlorosilane, allyldimethylchlorosilane, allyldimethylmethoxysilane, allyltrimethylsilane, diallyldichlorosilane, diallyldimethoxysilane, diallyldimethylsilane, etc. Can do.

  Among these, isoprene, amylene, 1,3-butadiene, 1-butene, α-pinene, β-pinene, limonene, styrene, indene, α-methylstyrene, methylstyrene (including ortho, meta, and para isomers) ), Methyl vinyl ether, ethyl vinyl ether, and isobutyl vinyl ether are particularly preferable from the viewpoint of copolymerization.

  When using other monomers copolymerizable with isobutylene, from the viewpoint of maintaining the effects of the present invention, the isobutylene-based polymer is preferably 50% by weight or less, more preferably 30% by weight or less, and still more preferably. You may contain in 10 weight% or less of range.

  In the present invention, a compound represented by the following general formula (I) is preferably used as the polymerization initiator.

R ¹ (X) n (I)
(Wherein R ¹ represents a monovalent or polyvalent aromatic hydrocarbon group or an aliphatic hydrocarbon group. X represents a desorption selected from the group consisting of chlorine, bromine, iodine, methoxy group and acetoxy group. Represents a leaving group, and n represents a natural number.)
It is not particularly restricted but includes compounds of the general formula (I), specifically, Kumirukurorido, 2-chloro-benzene, 4-tert-butyl - _{Kumirukurorido, CH 3 (CH 3) 2} CCH 2 (CH 3) 2 C-Cl, m-dicumulyl chloride, p-dicumulyl chloride, 5-tert-butyl-1,3-dicumulyl chloride, 5-methyl-1,3-dicumulyl chloride, Cl- (CH ₃ ) ₂ CCH ₂ (CH ₃ ) ₂ C—Cl, Cl— (CH ₃ ) ₂ CCH ₂ (CH ₃ ) ₂ CCH ₂ (CH ₃ ) ₂ C—Cl, 1,3,5-trimethyl milk chloride and the like can be mentioned.

  Among these, cumulyl chloride, m-dicumulyl chloride, p-dicumulyl chloride, and 1,3,5-tricumulyl chloride are particularly preferable in terms of reactivity and availability.

  In the present invention, the leaving group means a group represented by the X group in the general formula (I).

In the present invention, a polymerization catalyst coexists in the cationic polymerization system of isobutylene. Such a polymerization catalyst is not particularly limited as long as it is a Lewis acid catalyst generally used for cationic polymerization. For example, TiCl ₄ , TiBr ₄ , BCl ₃ , BF ₃ , BF ₃ .OEt ₂ , SnCl _{4 are used.} , AlCl ₃ , AlBr _{3 and} other metal halides; or TiCl ₃ (OiPr), TiCl ₂ (OiPr) ₂ , metal compounds having both a halogen atom and an alkoxide group on a metal such as TiCl (OiPr) ₃ ; Et ₂ AlCl, EtAlCl ₂ , Me ₂ AlCl, MeAlCl ₂ , Et _1.5 AlCl _1.5 , Me _1.5 AlCl _{1.5 and} other organometallic halides.

Of these, TiCl ₄ , EtAlCl ₂ , BCl ₃ , and SnCl ₄ are particularly preferable in view of catalytic ability and availability.

  The amount of the polymerization catalyst used is not particularly limited, and can be arbitrarily set in view of the polymerization characteristics of the monomer used, the polymerization concentration, the desired polymerization time, the exothermic behavior in the system, and the like. Preferably, it is used in the range of 0.1 to 200 times mol, more preferably in the range of 0.2 to 100 times mol, with respect to the compound represented by the above formula (I).

  The polymerization reaction in the present invention is preferably performed in an organic solvent. Such a polymerization solvent is not particularly limited as long as it is a solvent generally used in cationic polymerization, and halogenated hydrocarbons, aliphatic hydrocarbons, aromatic hydrocarbons, and the like can be used.

  Specific examples of the halogenated hydrocarbon include methyl chloride, methylene chloride, propyl chloride, butyl chloride, pentyl chloride, hexyl chloride and the like.

  Specific examples of the aliphatic and / or aromatic hydrocarbons include pentane, hexane, heptane, cyclohexane, methylcyclohexane, ethylcyclohexane, toluene, ethylbenzene, xylene (including ortho, meta, and para). Can be mentioned.

  Of these, methyl chloride, butyl chloride, hexane, cyclohexane, methylcyclohexane, ethylcyclohexane, and toluene are particularly preferred from the viewpoint of solubility and economy.

  These may be used alone or in combination of two or more. When mixing and using 2 or more types, it can mix in arbitrary ratios in view of solubility and a reactive viewpoint.

  In consideration of the viscosity of the solution and the ease of heat removal, the polymerization solvent is preferably set so that the solution concentration of the resulting polymer is 1 to 50% by weight, more preferably 3 to 35% by weight. %.

  The temperature at which the living cationic polymerization of the present invention is performed is not particularly limited. For example, it is preferable to mix and polymerize each component at a temperature of −100 ° C. or higher and lower than 50 ° C. Furthermore, from the energy cost and the stability of the polymerization reaction, −85 ° C. to 0 ° C. is more preferable. A temperature lower than −100 ° C. is not preferable because the polymer may precipitate. On the other hand, when the temperature is 50 ° C. or higher, the ratio of side reactions increases, and it may be difficult to obtain the target isobutylene polymer.

  The saturated cyclic ether compound used in the present invention is a compound having a 6-membered ring or more having only one oxygen atom in the ring (hereinafter sometimes simply referred to as the cyclic ether compound of the present invention). By adding the saturated cyclic ether compound to the living cationic polymerization system, the isobutylene polymer can be obtained by stabilizing the growth terminal of the isobutylene polymer and adjusting the catalyst activity of the polymerization catalyst to an appropriate level. An effect of increasing the content of the leaving group remaining in the polymer is obtained.

  In the cationic polymerization system, heteroatoms such as oxygen atoms contained in the ether compound are located in the vicinity of the Lewis acid catalyst or the terminal of the growth polymer and exert the above-described action. Since this essentially leads to a decrease in polymerization activity, the cyclic ether compound of the present invention has one oxygen atom in the ring.

  When an ether compound having two or more oxygen atoms is used, the polymerization rate and the productivity may be remarkably lowered, which is not preferable. In addition, the solubility in water may increase, which is not preferable because it may not be suitable for industrial production.

  As described above, from the viewpoint of industrial production, as the cyclic ether compound of the present invention, a compound having high lipophilicity can be preferably used. Specifically, the cyclic ether compound having 5 to 20 carbon atoms can be used. A compound is preferred.

  The cyclic ether compound of the present invention may be monocyclic or condensed cyclic, may have a transannular group or a spiro structure, and may be any carbon atom constituting the ring. It may have a saturated alkyl substituent at the position.

  This is because, in general, in a cationic polymerization system, a saturated aliphatic hydrocarbon substituent does not have reactivity, so that it does not affect the polymerization stabilization effect expected for a cyclic ether compound in the present invention, or the influence can be ignored. It is because it is small.

  Since the cyclic ether compound of the present invention has low solubility in water and can reduce environmental burden, it can be suitably used in industrial production. Various methods are known as a method for measuring the solubility in water. As an example, the method can be investigated by a method for a solubility test in water described later. The water solubility determined by this method is preferably 10% or less, more preferably 9% or less.

  The cyclic ether compound of the present invention is not particularly limited, and specific examples include tetrahydropyran, 2-methyltetrahydropyran, 2-ethyltetrahydropyran, 3-methyltetrahydropyran, 3-ethyltetrahydropyran, 4-methyl. Tetrahydropyran, 4-ethyltetrahydropyran, 2,2-dimethyltetrahydropyran, 2,3-dimethyltetrahydropyran, 2,4-dimethyltetrahydropyran, 3,3-dimethyltetrahydropyran, 3,4-dimethyltetrahydropyran, 4, , 4-dimethyltetrahydropyran, hexamethylene oxide (oxepane), 2-methylhexamethylene oxide, 3-methylhexamethylene oxide, 4-ethylhexamethylene oxide, heptamethylene oxide (oxocane), 2 Methylheptamethylene oxide, 3-methylheptamethylene oxide, 4-ethylheptamethylene oxide, octamethylene oxide (oxonan), nonamethylene oxide (oxecan), decamethylene oxide, octahydrobenzofuran, octahydroisobenzofuran, dodecahydrodibenzofuran, etc. Is mentioned.

  Among these, tetrahydropyran, 2-methyltetrahydropyran, 4-methyltetrahydropyran, 2,2-dimethyltetrahydropyran, and hexamethylene oxide are particularly preferable from the viewpoint of availability. These may be used alone, but two or more may be mixed and used in an arbitrary ratio.

The cyclic ether compound of the present invention is preferably used at a concentration of 1.0 × 10 ⁻⁴ to 1.0 mol / L from the viewpoint of productivity and economy, and from the viewpoint of the effect of suppressing side reactions, 1.0 * 10 < ^-3 > -1.0 mol / L is still more preferable.

If the concentration of the cyclic ether compound is less than 1.0 × 10 ⁻⁴ mol / L, the effect of suppressing side reactions may be difficult to obtain. On the other hand, if it exceeds 1.0 mol / L, productivity may be significantly reduced and there may be no economical advantage, which is not preferable.

  The cyclic ether compound of the present invention may be added to the system before the polymerization is started, or may be added during the polymerization. When adding in the middle of polymerization, it is preferable from the viewpoint of obtaining the effect of the present invention that the conversion of the isobutylene monomer is 70% or less, preferably 50% or less, more preferably 30% or less.

  However, since the cyclic ether compound of the present invention is used for the purpose of suppressing side reactions in cationic polymerization, it is most preferable to add it before starting the polymerization.

  In the production method of the present invention, in addition to the above cyclic ether compounds, pyridines, amines, amides, sulfoxides, esters, and metal compounds having an oxygen atom bonded to a metal atom as necessary. Various electron donor components such as these may coexist.

  As the electron donor component, those having a donor number defined as a parameter representing the strength of various compounds as an electron donor (electron donor) of 15 to 60 can be preferably used. -Methylpyridine, 2,6-dimethylpyridine, triethylamine, tributylamine, N, N-dimethylaminopyridine, N, N-dimethylformamide, N, N-dimethylacetamide, ethyl acetate, butyl acetate, titanium (IV) tetramethoxy , Titanium (IV) tetraisopropoxide, titanium (IV) butoxide and the like can be suitably used.

  Of these, 2-methylpyridine, 2,6-dimethylpyridine, triethylamine, N, N-dimethylformamide, N, N-dimethylacetamide, and titanium (IV) tetraisopropoxide are particularly preferred in terms of addition effect and availability. preferable.

  In general, the electron donor component is preferably used in an amount of 0.01 to 100 times mol with respect to the polymerization initiator. From the viewpoint of removal in the purification step after polymerization and waste reduction, 0.1 to 50 times mol. More preferably, it is used in the range of.

  In the production method of the present invention, when the polymerization reaction is completed, the polymerization catalyst is deactivated with pure water, alcohol or the like, and if necessary, the polymerization solution is purified with pure water or the like, so that a halogen group at the terminal or the like is obtained. An isobutylene-based polymer having the functional group can be obtained.

  The isobutylene polymer obtained by the production method of the present invention is one in which side reactions are extremely suppressed. Therefore, the molecular weight distribution (value represented by (weight average molecular weight Mw) / (number average molecular weight Mn)) measured by size exclusion chromatography (SEC) is preferably 1.00 to 1.37. Furthermore, the thing of 1.00-1.35 is still more preferable. When the value of the molecular weight distribution exceeds 1.37, it is not preferable because the handling ease of the isobutylene polymer may be inferior.

  The isobutylene polymer obtained by the production method of the present invention is one in which side reactions are extremely suppressed. Accordingly, an isobutylene polymer containing 96.0 mol% or more of a leaving group derived from a polymerization initiator is preferable. Considering further reaction after polymerization, it is more preferable to have 97.0 mol% or more of leaving groups in the polymer chain. An isobutylene polymer having only a leaving group of less than 96.0 mol% is not preferable because it may be inferior in the above physical properties.

  Since the leaving group still has reaction activity under appropriate reaction conditions, various reactive functional groups can be introduced or other monomers by further reacting the main chain end of the isobutylene polymer. It can also be derived into a new isobutylene polymer by bonding a polymer block mainly containing components.

  Such a reaction can be carried out by continuing the desired reaction without isolating the polymer at the time when the polymerization of isobutylene is completed, or after isolating the obtained isobutylene polymer once. You may attach to reaction again.

  The reactive functional group to be introduced is not particularly limited, but specific examples include allyl group, hydroxy group, carboxy group, amino group, phenol group, (meth) acryloyl group, mercapto group, epoxy group and the like. It is done.

  Specific examples of the block copolymer include a styrene-isobutylene block copolymer.

  Since the isobutylene polymer obtained in the present invention has a suppressed side reaction, the number average molecular weight Mn measured by size exclusion chromatography (SEC) is 1,000 to 1,000,000. preferable. Furthermore, an isobutylene polymer having a number average molecular weight of 2,000 to 500,000 is preferable because it can be suitably used for various sealants and adhesives.

  The production method of the present invention can be suitably carried out in a continuous polymerization reaction in addition to being suitably carried out in a batch polymerization reaction. In particular, in the cationic polymerization of isobutylene using an amine electron donor, it is known to react with hydrogen chloride by-produced by a chain transfer reaction to form a precipitate insoluble in a solvent. On the other hand, when the cyclic ether compound of the present invention is used, an insoluble precipitate is not formed with hydrogen chloride, so that the amount of such precipitate generated can be reduced or substantially zero. This can be particularly preferably performed in order to solve the problem of blockage in the tube in the continuous polymerization reaction.

  The isobutylene polymer obtained by the present invention utilizes excellent properties such as rubber elasticity, flexibility, viscoelasticity, weather resistance, gas permeation blocking property, and the like, so that it can be used as a coating material, sealing material, sealing material, tube, damper. And can be suitably used for applications such as gaskets.

  EXAMPLES Hereinafter, although an Example demonstrates this invention further in detail, this invention is not limited at all by these.

(Molecular weight measurement)
In the following examples, “number average molecular weight”, “weight average molecular weight” and “molecular weight distribution (ratio of weight average molecular weight to number average molecular weight)” are calculated by a standard polystyrene conversion method using size permeation chromatography (SEC). did. However, LCModule 1 manufactured by Waters was used as the SEC system, polystyrene cross-linked gel was packed as the GPC column (stationary phase) (ShodexGPCK-804; manufactured by Showa Denko KK), and chloroform was used as the moving layer.

(Analysis of polymer terminal structure)
The obtained isobutylene polymer was subjected to ¹ H NMR measurement, and the polymer terminal structure was analyzed by determining the area ratio of protons derived from the initiator residue and protons derived from each terminal structure. Here, the attribution of each peak was performed as follows.
Proton derived from initiator residue: peak near 7.21 ppm Proton derived from end of indane ring: peak near 6.98 ppm Proton derived from exoolefin end: peak near 4.64 ppm and 4.85 ppm Protons derived from nearby peak-end olefin end: 5.15 ppm peak-coupled end proton: 4.82 ppm peak-chlorine end proton: 1.66 ppm peak and 1 In the present invention, the end group structure of the obtained polymer is any one of the above-described five indane ring ends, exoolefin ends, end olefin ends, coupled ends, and chlorine ends (leaving group ends). Table 1 shows the ratio (mol%) of each terminal group structure. It was shown to.

(Solubility in water)
The solubility of each ether compound in water was investigated by the following method. In a sample tube, 6.0 g of butyl chloride and 0.50 g of each ether were weighed and mixed well to prepare a butyl chloride solution of an ether compound. This solution was analyzed by gas chromatography to determine the content (W ₁ %) of each ether compound. Next, 6.0 g of pure water was added to the previous sample tube, mixed well, and allowed to stand at room temperature. After the organic phase and the aqueous phase were separated, the organic phase was similarly analyzed by gas chromatography, and the content (W ₂ %) of each ether compound in the butyl chloride solution after extraction with water was determined. From the following formula, the solubility of each ether compound in water was calculated.

Solubility in water (%) = (W ₁ −W ₂ ) / W ₁ × 100
If the solubility in water required by this test is large, it is considered not to be easily mixed into factory effluent even in industrial production. Conversely, a small value indicates that it tends to stay in the organic phase and is not easily extracted into the aqueous phase. Therefore, it is preferable because mixing into factory wastewater can be suppressed and the load on the environment is reduced.

Example 1
After substituting the inside of a 500 mL separable flask with nitrogen, 24 mL of n-hexane (dried with molecular sieves) and 214 mL of butyl chloride (dried with molecular sieves) were added, and −70 with stirring under a nitrogen atmosphere. Cooled to ° C. Then, 87 mL (0.922 mol) of isobutylene), 1.02 g (0.00441 mol) of p-dicumyl chloride and 0.18 ml (0.0015 mol) of 2,6-lutidine, 0.42 ml of hexamethylene oxide (0.0038 mol, 1.16 × 10 ⁻² mol / L) was added. After the reaction mixture was cooled to -73 degrees, 0.97 mL (0.00883 mol) of titanium tetrachloride was added to initiate polymerization. After the polymerization was started, the residual isobutylene concentration was measured by gas chromatography, and the polymerization of isobutylene was completed when 99.9% or more of the charged isobutylene was consumed. The reaction mixture was poured into a large amount of pure water heated to 60 ° C., and stirred at the same temperature for 60 minutes to deactivate the polymerization catalyst. Stirring was stopped, the mixture was allowed to stand for 30 minutes, and the aqueous layer was drained. Next, 500 mL of pure water was added, stirred at 60 ° C. for 30 minutes, then allowed to stand for 30 minutes, and the aqueous layer was drained. The same operation was repeated twice to confirm that the pH of the wastewater was 7, and the purification was completed. The obtained organic phase was taken out and the solvent was distilled off under reduced pressure to obtain an isobutylene polymer. The results of molecular weight, molecular weight distribution, and structural analysis of the polymer end groups were as shown in Table 1.

(Example 2)
An isobutylene polymer was synthesized and analyzed in the same manner as in Example 1 except that tetrahydropyran (same concentration) was used instead of hexamethylene oxide. The results are shown in Table 1.

(Comparative Example 1)
An isobutylene polymer was synthesized and analyzed in the same manner as in Example 1 except that the cyclic ether of the present invention was not used. The results are shown in Table 1.

(Comparative Example 2)
An isobutylene polymer was synthesized and analyzed in the same manner as in Example 1 except that tetrahydrofuran (same concentration) was used instead of hexamethylene oxide. The results are shown in Table 1.

(Comparative Example 3)
An isobutylene polymer was synthesized and analyzed in the same manner as in Example 1 except that dipropyl ether (same concentration) was used instead of hexamethylene oxide. The results are shown in Table 1.

(Comparative Example 4)
An isobutylene polymer was synthesized and analyzed in the same manner as in Example 1 except that dibutyl ether (same concentration) was used instead of hexamethylene oxide. The results are shown in Table 1.

  In Examples 1 and 2, when the cyclic ether compound of the present invention is used, an isobutylene polymer having a small molecular weight distribution and a high terminal chlorine group residual ratio is obtained. It can be seen that side reactions are suppressed and high living polymerizability is obtained.

  The reason why the effect of suppressing side reactions is higher than that of tetrahydrofuran in Comparative Example 2 is not necessarily clear, but since hexamethylene oxide and tetrahydropyran have more carbon atoms constituting the ring than tetrahydrofuran, electron donation of oxygen atoms It is speculated that high polymerization control could be realized by enhancing the property and facilitating coordination to the cation end of the titanium catalyst or polymer.

  In Comparative Example 1, it can be seen that when the cyclic ether compound of the present invention is not used, the molecular weight distribution is large and the polymerization control is insufficient. In particular, it can be seen that the weight average molecular weight Mw of the obtained isobutylene polymer is larger than those in Examples 1 and 2. This is presumed to be due to uncontrolled polymerization starting from the water present in the system. Therefore, when the cyclic ether compound of the present invention is not used, it is apparent that side reactions are not sufficiently suppressed.

  When tetrahydrofuran was used in Comparative Example 2, the residual rate of terminal chlorine groups was sufficient, but an isobutylene polymer having a high weight average molecular weight was obtained as in Comparative Example 1. Therefore, it can be seen that tetrahydrofuran does not sufficiently suppress side reactions.

  In Comparative Examples 3 and 4, when a chain ether compound is used, not only an exo-olefin end and an end-olefin end are generated by a chain transfer reaction that can occur normally, but also a coupling structure of polymers produced by further reaction Was also recognized. This is also clear from the fact that each of the obtained isobutylene polymers has a very large weight average molecular weight. Therefore, the effect of controlling the side reaction cannot be obtained with the chain ether compound.

  From the above, the present invention is a production method in which an isobutylene polymer having a high content of a leaving group can be obtained by effectively suppressing side reactions by coexisting a specific cyclic ether compound. Is clear.

  Table 2 also shows that the cyclic ether compounds of the present invention used in Examples 1 and 2 are much less soluble in water than tetrahydrofuran used in Comparative Example 2. Therefore, it can be seen that the cyclic ether compound of the present invention is a raw material suitable for industrial production in that it can realize a reduction in environmental load.

Claims (5)

A method for producing an isobutylene polymer by living cationic polymerization in the presence of a polymerization initiator, a polymerization catalyst, and a saturated cyclic ether compound, wherein the saturated cyclic ether compound has only one oxygen atom in the ring. A process for producing an isobutylene polymer, which is a compound having a 6-membered ring or more. The method for producing an isobutylene polymer according to claim 1, wherein the molecular weight distribution (Mw / Mn) of the isobutylene polymer is 1.00 to 1.37. The method for producing an isobutylene polymer according to claim 1 or 2, wherein the isobutylene polymer contains 96.0 mol% or more of a leaving group derived from the polymerization initiator. The said saturated cyclic ether type compound is made to coexist in the density | concentration of 1.00 * 10 < ^-4 > -1.00 mol / L, The manufacture of the isobutylene type polymer as described in any one of Claims 1-3 characterized by the above-mentioned. Method. The saturated cyclic ether compound is at least one selected from the group consisting of tetrahydropyran, 2-methyltetrahydropyran, 4-methyltetrahydropyran, 2,2-dimethyltetrahydropyran, and hexamethylene oxide. The manufacturing method of the isobutylene polymer as described in any one of Claims 1-4.