JP2013064085A - Method for polymerizing sulfonic acid group-containing vinyl monomer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for polymerizing a sulfonic acid group-containing vinyl monomer in a high yield even if using the monomer or a solvent having an active proton, or the both.SOLUTION: The method for polymerizing a sulfonic acid group-containing vinyl monomer uses as a polymerization initiator a zincate complex represented by t-BuRZnM or t-BuR'ZnM[wherein n is an integer of 1 to 3; m is an integer of 1 to 4; l is a real number of 1 to 2; R and R' may be the same or different, and are each 1-12C alkyl, alkenyl, aryl or arylalkyl; and M is lithium, magnesium or a magnesium halide, MgX (X is one of chlorine, bromine and iodine)].

Description

  The present invention relates to a method for polymerizing a sulfonic acid group-containing vinyl monomer using a specific zinc art complex as a polymerization initiator.

Polymers containing sulfonic acid groups are useful as acid catalysts, cleaning agents, ion exchange membranes or electrolyte membranes.
As a method for producing a polymer containing a sulfonic acid group, there are two methods: a method of sulfonating a polymer not containing a sulfonic acid group with a sulfonating agent, and a method of synthesizing by polymerization using a sulfonic acid group-containing monomer.

The method of production by sulfonation of a polymer has problems such as control of the regioselectivity of sulfonation, residual of a reactant used for sulfonation, and suppression of side reactions such as crosslinking.

  On the other hand, a polymerization using a sulfonic acid group-containing monomer, particularly a polymerization of a sulfonic acid group-containing vinyl monomer, generally uses a radical initiator as an initiator (see, for example, Patent Documents 1 and 2). However, in carrying out radical polymerization, since the polymerization rate and the molecular weight of the produced polymer are affected by a small amount of impurities, it was necessary to pay attention to purification of monomers, solvents, etc., and removal of dissolved oxygen in the solvent during polymerization. .

In anionic polymerization using an organometallic compound as an initiator, when an active proton is present in a solvent or monomer, the initiator is deactivated, so that a polymer cannot be obtained.
However, Uchiyama et al., Di-lithium tetra-t-butylzincate is useful as a polymerization catalyst for N-isopropylacrylamide, N, N-dimethylacrylamide, hydroxyethyl methacrylate, and the like, and this catalyst includes hydrous THF (tetrahydrofuran) and the like. It was proposed as an epoch-making method capable of allowing living polymerization anionic polymerization to proceed even in a solution containing water (see, for example, Patent Document 3).

Further, it has been reported that polymerization of an acrylate monomer in an aqueous system similarly proceeds even with a zinc ate complex containing at least one t-butyl group (see, for example, Patent Documents 4 and 5).
It was shown that by using these zinc ate complexes, it is possible to polymerize acrylate monomers without requiring strict purification of the monomers and solvents.

  However, it has not been shown that these zinc art complexes can be used for the polymerization of vinyl monomers containing sulfonic acid groups.

JP-A-10-139816 JP-T-2006-502249 JP 2004-292328 A JP 2007-320938 A Table 2007/142188

An object of the present invention is to solve the above-mentioned problems, and a polymer of a sulfonic acid group-containing vinyl monomer can be produced in a high yield even when a monomer having an active proton, a solvent, or both are used. It is an object of the present invention to provide a method for polymerizing a sulfonic acid group-containing vinyl monomer capable of obtaining a polymer.
That is, none of the prior art suggests an optimum substance as a polymerization initiator for a sulfonic acid group-containing vinyl monomer.

As a result of intensive efforts to solve this problem, the present inventors have found that an organozinc ate complex having at least one t-butyl group on a zinc atom is suitable as a polymerization initiator for an anion polymerizable monomer. As a result, the present invention has been completed.
That is, the present invention is a method for polymerizing a sulfonic acid group-containing vinyl monomer, characterized in that a zinc art complex represented by the following general formula (1) or (2) is used as a polymerization initiator.
_{t-Bu n R 3-n} ZnM (1)
(In the formula, n is an integer of 1 to 3, M represents a magnesium halide represented by lithium, magnesium, or MgX (X represents any one of chlorine, bromine, and iodine), and R represents one carbon atom. Represents an alkyl group, an alkenyl group, an aryl group, or an arylalkyl group of ˜12.)
t-Bu _m R ′ _4-m ZnM _l (2)
(In the formula, m is an integer of 1 to 4, l is a real number of 1 to 2, R 'may be the same as or different from R of formula (1), and an alkyl group having 1 to 12 carbon atoms. , An alkenyl group, an aryl group, or an arylalkyl group, and M represents a magnesium halide represented by lithium, magnesium, or MgX (X represents any one of chlorine, bromine, and iodine).

The polymerization initiator of the present invention is an organozinc ate complex having at least one t-butyl group represented by the following general formula (1) or (2).
_{t-Bu n R 3-n} ZnM (1)
t-Bu _m R ′ _4-m ZnM _l (2)
Here, n is an integer selected from 1 to 3, m is an integer of 1 to 4, and l is a real number of 1 to 2.
R and R ′ may be the same or different and each represents an alkyl group, alkenyl group, aryl group or arylalkyl group having 1 to 12 carbon atoms. Specifically, methyl group, ethyl group, i-propyl group, n-propyl group, n-butyl group, i-butyl group, s-butyl group, n-pentyl group, t-amyl group, n-hexyl group, n-heptyl group, n-octyl group, n-nonyl group, n-decyl group, vinyl group, cyclopentadienyl group, phenyl group, and benzyl group are shown.
M represents a magnesium halide represented by lithium, magnesium, or MgX (X represents any one of chlorine, bromine, and iodine).

More specific examples of the organozinc ate complex used in the present invention include those represented by the general formula (1)
_{t-Bu n R 3-n} ZnM (1)
(T-butyl) lithium dimethyl zincate, (t-butyl) lithium diethyl zincate, (t-butyl) lithium dibutyl zincate, (t-butyl) lithium divinyl zincate, (n-butyl) ) Lithium organic zincate such as lithium dit-butylzincate, lithium bis (t-butyl) phenylzincate, lithium trit-butylzinclate, (t-butyl) dimethylzinc zincate chloride, (t-butyl) ) Magnesium dimethylzinc acid bromide, (t-butyl) magnesium dimethylzincate iodide, di (t-butyl) methylmagnesium zinc chloride, di (t-butyl) methylmagnesium bromide, di (t-butyl) methyl Magnesium zincate iodide, diethyl (t-butyl) zincate magnesium Muchloride, diethyl (t-butyl) zinc acid magnesium bromide, diethyl (t-butyl) magnesium zincate iodide, ethyl di (t-butyl) zinc zinc chloride, ethyl di (t-butyl) zinc magnesium bromide, ethyl di (t -Butyl) magnesium zincate iodide, (t-butyl) dibutylmagnesium chloride, (t-butyl) dibutylmagnesium bromide, (t-butyl) dibutylmagnesium iodide, di (t-butyl) butyl Magnesium zinc chloride, di (t-butyl) butyl magnesium zinc bromide, di (t-butyl) butyl magnesium zinc iodide, (t-butyl) divinyl magnesium zinc chloride, (t-butyl) dibi Magnesium bromide bromide, (t-butyl) divinylmagnesium zinc iodide, diphenyl (t-butyl) magnesium chloride, diphenyl (t-butyl) magnesium bromide, diphenyl (t-butyl) magnesium zinc iodide Dide, Phenyldi (t-butyl) zinc acid magnesium chloride, Phenyldi (t-butyl) zinc magnesium bromide, Phenyldi (t-butyl) zinc magnesium iodide, Tri-t-butylzinc magnesium chloride, Tri-t-butylzinc Examples thereof include organic magnesium zinc halides such as magnesium magnesium bromide and magnesium tri-t-butylzincate iodide.

In addition, the general formula (2)
t-Bu _m R _4-m ZnM _l (2)
Specific examples of the organic zinc ate complex represented by the formula: Dikis tetrakis-t-butylzinc zincate, dilithium tri-t-butylmethylzincate, dilithium tri-t-butylethylzincate, tri-t-butyl-n-propylzinc Dilithium acid, tri-t-butyl-i-propyl zincate dilithium, tri-t-butyl-n-butyl dizinc zincate, tri-t-butyl-i-butyl dizinc zincate, tri-t-butyl-s- Dilithium butyl zincate, dilithium dimethyldi-t-butylzincate, dilithium diethyldi-t-butylzincnate, dilithium di-t-butyldi-n-propylzinclate, dilithium di-t-butyldi-i-propylzincnate, di -Di-n-butyl di-n-butyl zincate, di-n-butyl di-i-butyl zincate Di-n-butyl di-s-butyl zincate dilithium, methylethyl di-t-butyl zincate dilithium, methyl-n-butyl-di-t-butylzinc zincate, methyl-s-butyl-di-t-butylzinc acid Dilithium, ethyl-n-butyl-di-t-butylzinc zincate, ethyl-s-butyl-di-t-butylzinc zincate, dimethylethyl-t-butylzinclate, dimethyl-n-butyl-t- Dilithium butyl zincate, dilithium dimethyl-s-butyl-t-butyl zincate, dilithium dimethylethyl-t-butyl zincate, dilithium diethylmethyl-t-butylzincate, dilithium diethyl-n-butyl-t-butylzincate , Dilithium organic zincate such as diethyl-s-butyl-t-butylzinc zincate, tetrakis -T-butyl magnesium zincate, magnesium tri-t-butylmethylzincate, magnesium tri-t-butylethylzincate, magnesium tri-t-butyl-n-propylzinc, tri-t-butyl-i-propylzinc Magnesium, magnesium tri-t-butyl-n-butyl zincate, magnesium tri-t-butyl-i-butyl zincate, magnesium magnesium tri-t-butyl-s-butylzincate, magnesium dimethyldi-t-butylzincate Diethyldi-t-butylmagnesium zincate, di-t-butyldi-n-propylmagnesium zincate, di-t-butyldi-i-propylmagnesium zincate, di-n-butyldi-n-butylmagnesium zincate, di- n-Butyldi-i-butylmagnesium zincate, di-n-butyldi-s-buty Magnesium zinc oxide, methyl ethyl di-t-butyl magnesium zincate, methyl-n-butyl-di-t-butyl magnesium zincate, methyl-s-butyl-di-t-butyl magnesium zincate, ethyl n-butyl- Di-t-butylmagnesium zincate, ethyl-s-butyl-di-t-butylmagnesium zincate, dimethylethyl-t-butylmagnesium zincate, dimethyl-n-butyl-t-butylmagnesium zincate, dimethyl-s -Butyl-t-butylmagnesium zincate, dimethylethyl-t-butylmagnesium zincate, diethylmethyl-t-butylmagnesium zincate, diethyl-n-butyl-t-butylmagnesium zincate, diethyl-s-butyl-t -Mentioning organic magnesium zincate such as butyl magnesium zincate Kill.

  These zinc art complexes can be used alone or in a mixture as a polymerization initiator.

The zinc art complex having a t-butyl group of the present invention can be synthesized by a reaction between a zinc compound and an organolithium compound or an organomagnesium compound in an inert gas atmosphere.
For example, it can be synthesized by reacting an organic zinc compound such as dialkyl zinc, diaryl zinc or dialkenyl zinc with an organic magnesium reagent having 1 to 2 equivalents of t-butyllithium or t-butyl group.

Moreover, what reacted 1 to 2 equivalent organolithium reagent or organomagnesium reagent with respect to di-t-butyl zinc can also be used.

Or it can synthesize | combine by making zinc halides, such as zinc chloride, into a starting source, and making 3-4 equivalent of an organic lithium reagent or an organic magnesium reagent react with zinc. At this time, the zinc art complex in the present invention can be synthesized by using an organomagnesium reagent having at least one equivalent of t-butyllithium or t-butyl group.

  For these syntheses, ether solvents such as tetrahydrofuran, diethyl ether, dibutyl ether, cyclopentyl methyl ether, or hydrocarbon solvents such as pentane, hexane, heptane, toluene, and mixtures thereof can be used as reaction solvents. . Among these, an ether solvent is preferably used from the viewpoint of controlling the temperature during the reaction or maintaining uniformity.

  In the present invention, the synthesized zinc art complex solution can be used as it is for polymerization.

  Examples of the sulfonic acid group-containing vinyl monomer used for polymerization include vinyl sulfonic acid, allyl sulfonic acid, 4-styrene sulfonic acid, methallyl sulfonic acid, 2- (methacryloyloxy) ethane sulfonic acid, and 2-acrylamido-2-methylpropane. Examples thereof include sulfonic acids and alkali metal salts such as lithium, sodium and potassium, alkaline earth metal salts such as magnesium and calcium, and ammonium salts. These may be used alone or in combination of two or more.

Moreover, you may copolymerize a sulfonic acid group containing vinyl monomer and another vinyl monomer.
Specific examples of other vinyl monomers include acrylic acid, methacrylic acid and methyl acrylate, methyl methacrylate, ethyl acrylate, ethyl methacrylate, hydroxyethyl methacrylate, N-isopropylacrylamide, acrylamide, and N-isopropylmethacrylamide. Acrylic monomers, styrene, α-methylstyrene, α-methyl-p-methylstyrene, 2-methylstyrene, 3-methylstyrene, 4-methylstyrene, 4-t-butylstyrene, 4-t-butoxystyrene, Hydrocarbon vinyl monomers such as 4-t-butoxy-α-methylstyrene, 4-chlorostyrene, 4- (chloromethyl) styrene, 4-methoxystyrene, 4-aminostyrene, 4-vinylbenzoic acid, butadiene, and isoprene Is an example That.

  The solvent used for the polymerization may be a commonly used solvent, for example, a hydrocarbon solvent such as toluene, xylene, hexane, cyclohexane, heptane, an ether solvent system such as THF, diethyl ether, methanol, ethanol, isopropanol, etc. Alcohols and water. In general, water and alcohols easily react with an organometallic compound, so that when they are used as a solvent, the organometallic compound loses the polymerization initiation function. However, the zinc art complex of the present invention can obtain a polymer in a high yield without losing the polymerization initiation function even when a protic solvent system such as water or an alcohol solvent is used as a polymerization solvent.

  The amount of the zinc ate complex used in the polymerization in the present invention is not particularly limited, but it is preferably used in the range of 0.001 to 10 mol with respect to 100 mol of the monomer. In some cases, the polymerization activity does not occur, and when this range is exceeded, a large amount of metal residue may be contained in the obtained polymer, and a step for removing it may be necessary.

  By using the organozinc art complex described in the present invention as a polymerization initiator, a polymer of a sulfonic acid group-containing vinyl monomer can be obtained in a high yield even when a monomer and / or solvent having an active proton is used. Can be obtained.

EXAMPLES The present invention will be described below with reference to examples, but the present invention is not limited to these examples.
[measuring equipment]
¹ H-NMR measurement was performed using Gemini-300 manufactured by Varian.
The number average molecular weight and the weight average molecular weight were measured by gel permeation chromatography (GPC) under the following conditions.
Separation column: TSK gel α-6000 + α-3000
Column temperature: 40 ° C
Mobile phase: phosphate buffer (pH = 7) / acetonitrile = 9/1
Movement speed: 0.6 ml / min Detector: UV detector, 230 nm

(Example 1) Polymerization of sodium p-styrene sulfonate with t-Bu ₄ ZnLi ₂ 15.0 wt.% Of an aqueous solution (50 mL) of sodium p-styrene sulfonate hydrate at 0 ° C. in a nitrogen atmosphere at 0 ° C. 0.6 g (% by weight) of a THF solution of t-Bu ₄ ZnLi ₂ (purchased from Kanto Chemical Co., Inc.) was added and stirred at room temperature for 1 hour.
¹ H-NMR measurement of the obtained aqueous solution confirmed that poly (sodium p-styrenesulfonate) was obtained at a conversion rate of 96%.
As a result of GPC measurement, the number average molecular weight of poly (sodium p-styrenesulfonate) was 45,000, and the weight average molecular weight was 100,000.

(Example 2) Preparation of t-BuEt ₂ ZnLi Under a nitrogen atmosphere, 20 mL of THF and 1.78 g (14.4 mmol) of diethyl zinc were added to a 100 mL eggplant flask and cooled to -70 ° C. Under stirring conditions, 5.76 g (14.4 mmol) of a 16.0 wt% t-butyllithium pentane solution was added dropwise. After dropping, the mixture was stirred at -70 ° C for 30 minutes and then warmed to room temperature. The solvent was concentrated under reduced pressure, and diluted with THF to obtain a 9.3 wt% THF solution of t-BuEt ₂ ZnLi.

_t-BuEt 2 ZnLi in accordance polymerization Under a nitrogen atmosphere sodium p- styrenesulfonate, in at 0 ° C. p- styrene solution of sodium sulfonate hydrate 5.0g (50mL), 9.3wt% of t-BUET ₂ 0.6 g of ZnLi in THF was added and stirred at room temperature for 1 hour.
¹ H-NMR measurement of the obtained aqueous solution confirmed that poly (sodium p-styrenesulfonate) was obtained at a conversion of 79.6%.

(Comparative Example 1) Preparation of n-Bu ₂ Et ₂ ZnLi ₂ Under a nitrogen atmosphere, 30 mL of THF and 2.75 g (22.2 mmol) of diethyl zinc were added to a 100 mL eggplant flask and cooled to -70 ° C. Under stirring, 19.0 g (45.5 mmol) of a hexane solution of 15.3 wt% -n-butyllithium was added dropwise. After dropping, the mixture was stirred at -70 ° C for 30 minutes and then warmed to room temperature. The solvent was removed under reduced pressure to obtain 38.1 wt% of a THF solution of n-Bu ₂ Et ₂ ZnLi ₂ .

Polymerization of p-sodium styrenesulfonate with n-Bu ₂ Et ₂ ZnLi _{2 In} an aqueous solution (50 mL) of 5.0 g of sodium p-styrenesulfonate hydrate at 0 ° C. in a nitrogen atmosphere, 38.1 wt% n 0.2 g of a THF solution of -Bu ₂ Et ₂ ZnLi ₂ was added and stirred at room temperature for 1 hour.
As a result of ¹ H-NMR measurement of the obtained aqueous solution, only the p-sodium styrenesulfonate peak was observed, and no polymer was observed.

  From the above results, it was confirmed that a zinc ate complex having no t-butyl group does not function as a polymerization initiator for a sulfonic acid group-containing vinyl monomer such as sodium p-styrenesulfonate.

The method for polymerizing a sulfonic acid group-containing vinyl monomer according to the present invention is useful for obtaining an acid catalyst, a cleaning agent, an ion exchange membrane or an electrolyte membrane.

Claims (3)

A method for polymerizing a sulfonic acid group-containing vinyl monomer, wherein a zinc art complex represented by the following general formula (1) or (2) is used as a polymerization initiator.
_{t-Bu n R 3-n} ZnM (1)
(In the formula, n is an integer of 1 to 3, M represents a magnesium halide represented by lithium, magnesium, or MgX (X represents any one of chlorine, bromine, and iodine), and R represents one carbon atom. Represents an alkyl group, an alkenyl group, an aryl group, or an arylalkyl group of ˜12)
t-Bu _m R ′ _4-m ZnM _l (2)
(In the formula, m is an integer of 1 to 4, l is a real number of 1 to 2, R 'may be the same as or different from R of formula (1), and an alkyl group having 1 to 12 carbon atoms. , An alkenyl group, an aryl group, or an arylalkyl group, and M represents a magnesium halide represented by lithium, magnesium, or MgX (X represents any one of chlorine, bromine, and iodine). The method for polymerizing a sulfonic acid group-containing vinyl monomer according to claim 1, wherein the solvent used for the polymerization is water. The method for polymerizing a sulfonic acid group-containing vinyl monomer according to claim 1 or 2, wherein the sulfonic acid group-containing vinyl monomer is styrenesulfonic acid or a metal salt of styrenesulfonic acid.