JP2020117643A - Compound, chain transfer agent, and method for producing polymer - Google Patents

Abstract

To provide a compound that has excellent water solubility and can be used as a chain transfer agent.SOLUTION: The present inventions discloses a chain transfer agent that is a trithiocarbonyl compound having two hydroxy groups and amide groups at a terminal, or amide groups at both terminals, for example, represented by general formulas (1), (2). In general formula (1), Lis an amide group, a methylene group, or a C2-10 alkylene group, at least one methylene group constituting the alkylene group being optionally substituted with an amide group. In general formula (2), Lis direct bond, a methylene group, or a C2-10 alkylene group, the at least one methylene group being optionally substituted with an amide group.SELECTED DRAWING: None

Description

The present disclosure relates to compounds, chain transfer agents, and methods of making polymers.

Living radical polymerization is known as a precise polymerization method capable of controlling the degree of polymerization of a polymer and the arrangement of monomers in the molecular chain of the polymer. As living radical polymerization, a polymerization method using nitroxide (NMP method), an atom transfer radical polymerization method (ATRP method), and a reversible addition-fragmentation chain transfer polymerization (RAFT polymerization) method are known.

The RAFT polymerization method has attracted attention because of its high resistance to oxygen, the fact that it is not necessary to use a metal catalyst, and that it can utilize thiol chemistry. In the RAFT polymerization method, a chain transfer agent having a specific functional group such as a thiocarbonylthio group (also referred to as RAFT agent) is used. In RAFT polymerization, by reacting with a monomer in a chain, repeating exchange of radicals that are active species between the growth end of the polymerization and a specific functional group such as a thiocarbonylthio group of a chain transfer agent. Polymerization proceeds.

Since the RAFT polymerization method has the above-mentioned characteristics, it has been attracting attention as a method for industrially utilizing living radical polymerization. However, RAFT polymerization is a polymerization reaction generally performed in the presence of an organic solvent, and its application and development are difficult. Therefore, in order to realize RAFT polymerization using water as a solvent (also referred to as water-based RAFT polymerization), a water-soluble chain transfer agent has been studied in recent years. For example, it has been proposed to use a salt of a chain transfer agent having a carboxyl group as a water-soluble chain transfer agent (for example, Patent Document 1).

International publication 2016/182711

However, the water solubility of the water-soluble chain transfer agents currently being investigated is not always sufficient. Therefore, even in the case of aqueous RAFT polymerization, it is the actual situation that an organic solvent is mixed with the solvent in order to dissolve the chain transfer agent and the like to prepare a uniform solution. Considering industrial use, it is desirable to reduce the amount of organic solvent used as much as possible. Further, depending on the degree of water solubility of the monomer compound and the obtained polymer, it may be difficult to dissolve in an organic solvent, and it may be difficult to prepare a uniform solution when the organic solvent is mixed with the polymerization system. Therefore, it would be useful to have a chain transfer agent with excellent water solubility that can dissolve a sufficient amount without using an organic solvent.

The present disclosure aims to provide a compound having excellent water solubility and usable as a chain transfer agent. The present disclosure also aims to provide a chain transfer agent having excellent water solubility. The present disclosure also aims to provide a method for producing a polymer using the above-mentioned chain transfer agent.

One aspect of the present disclosure provides a compound represented by the following general formula (1), the following general formula (2), the following general formula (3), or the following general formula (4).

In formulas (1) and (3), L ¹ represents an amide group, a methylene group, or an alkylene group having 2 to 10 carbon atoms, and at least one of the methylene groups constituting the alkylene group is an amide group. It may be substituted. In formulas (2) and (4), L ² represents a direct bond, a methylene group, or an alkylene group having 2 to 10 carbon atoms, and at least one of the methylene groups constituting the alkylene group is an amide group. It may be substituted.

Since the above compound is a compound having two hydroxyl groups at the terminals, a compound having amide groups at the terminals, or a compound having amide groups at both terminals, it is excellent in water solubility. The above compound also has a trithiocarbonyl group and also functions as a chain transfer agent in the reversible addition-fragmentation chain transfer polymerization method.

In formulas (1) and (3), L ¹ represents an alkylene group having 2 to 10 carbon atoms, and at least one of the methylene groups constituting the alkylene group may be substituted with an amide group, In formulas (2) and (4), L ² represents an alkylene group having 2 to 10 carbon atoms, and at least one of the methylene groups constituting the alkylene group may be substituted with an amide group. In the compounds represented by the general formula (1) and the general formula (3), by providing an alkylene group having 2 to 10 carbon atoms between the trithiocarbonyl group and the two hydroxyl groups, it is more excellent in hydrolysis resistance. It can be a compound. In the compounds represented by the general formula (2) and the general formula (4), a compound more excellent in hydrolysis resistance by providing an alkylene group having 2 to 10 carbon atoms between the trithiocarbonyl group and the amide group. Can be Further, by substituting at least one of the methylene groups constituting the alkylene group with an amide group, it is possible to sufficiently suppress the decrease in water solubility of the compound.

In the above compound, in the general formula (1) and the general formula (3), L ¹ may be a methylene group or —CH ₂ CH ₂ CONHCH ₂ —, and the general formula (2) and the general formula (4) ), L ² may be a methylene group or —CH ₂ CH ₂ CONHCH ₂ —.

One aspect of the present disclosure includes a compound represented by the following general formula (1), a compound represented by the following general formula (2), a compound represented by the following general formula (3), and a general formula (4) below. Provided is a chain transfer agent containing at least one selected from the group consisting of the represented compounds.

In formulas (1) and (3), L ¹ represents an amide group, a methylene group, or an alkylene group having 2 to 10 carbon atoms, and at least one of the methylene groups constituting the alkylene group is an amide group. It may be substituted. In formulas (2) and (4), L ² represents a direct bond, a methylene group, or an alkylene group having 2 to 10 carbon atoms, and at least one of the methylene groups constituting the alkylene group is an amide group. It may be substituted.

Since the chain transfer agent contains a compound having two hydroxyl groups at the terminals, a compound having an amide group at the terminals, or a compound having an amide group at both terminals, it has excellent water solubility. The above compound also has a trithiocarbonyl group and has a function as a chain transfer agent in the reversible addition-fragmentation chain transfer polymerization method.

In formulas (1) and (3), L ¹ represents an alkylene group having 2 to 10 carbon atoms, and at least one of the methylene groups constituting the alkylene group may be substituted with an amide group, In formulas (2) and (4), L ² represents an alkylene group having 2 to 10 carbon atoms, and at least one of the methylene groups constituting the alkylene group may be substituted with an amide group. In the compounds represented by the general formula (1) and the general formula (3), by providing an alkylene group having 2 to 10 carbon atoms between the trithiocarbonyl group and the two hydroxyl groups, it is more excellent in hydrolysis resistance. It can be a compound. In the compounds represented by the general formula (2) and the general formula (4), a compound more excellent in hydrolysis resistance by providing an alkylene group having 2 to 10 carbon atoms between the trithiocarbonyl group and the amide group. Can be Further, by substituting at least one of the methylene groups constituting the alkylene group with an amide group, it is possible to sufficiently suppress the decrease in water solubility of the compound.

In the above-mentioned chain transfer agent, in the general formula (1) and the general formula (3), L ¹ may be a methylene group or —CH ₂ CH ₂ CONHCH ₂ —, and the general formula (2) and the general formula ( In 4), L ² may be a methylene group or —CH ₂ CH ₂ CONHCH ₂ —.

One aspect of the present disclosure performs reversible addition-fragmentation chain transfer polymerization in a solution containing a monomer composition containing a compound having an ethylenically unsaturated bond, a chain transfer agent, a polymerization initiator, and water. There is provided a method for producing a polymer, which comprises the steps, wherein the chain transfer agent contains the chain transfer agent described above.

In the method for producing a polymer, the monomer composition can be polymerized in an aqueous system using the chain transfer agent. Since it is capable of reversible addition-fragmentation chain transfer in an aqueous system, it is useful when developing living radical polymerization into industrial applications.

According to the present disclosure, it is possible to provide a compound that has excellent water solubility and can be used as a chain transfer agent. The present disclosure can also provide a chain transfer agent having excellent water solubility. The present disclosure can also provide a method for producing a polymer using the above-mentioned chain transfer agent.

FIG. 1 is a ¹ H-NMR spectrogram of a compound represented by the formula (1a). FIG. 2 is a ¹ H-NMR spectrogram of the compound represented by the formula (1b). FIG. 3 is a ¹³ C-NMR spectrogram of the compound represented by the formula (1b). FIG. 4 is a graph showing the results of UV spectrum measurement of the compound represented by formula (1b). FIG. 5 is a ¹ H-NMR spectrogram of the compound represented by formula (3a).

Hereinafter, embodiments of the present disclosure will be described. However, the following embodiments are examples for describing the present disclosure, and are not intended to limit the present disclosure to the following contents.

The present disclosure provides compounds useful as chain transfer agents in reversible addition-fragmentation chain transfer polymerization processes. One embodiment of the above compound is a compound having a 1-carboxyethyl group (a structure derived from propanoic acid) or a 1-amidoethyl group (a structure derived from propionic acid amide) at one end of a trithiocarbonyl group. It is represented by the formula (1), the following general formula (2), the following general formula (3) or the following general formula (4). Since these compounds contain a structure having a hydroxyl group or an amide group on the opposite side of the trithiocarbonyl group from the 1-carboxyethyl group or the 1-amidoethyl group, they are excellent in water solubility.

In general formula (1), L ¹ represents an amide group, a methylene group, or an alkylene group having 2 to 10 carbon atoms. In general formula (1), L ¹ may be an alkylene group having 2 to 10 carbon atoms. The carbon number of the alkylene group may be, for example, 2 to 8, 2 to 6, 2 to 5, 2 to 4, or 2 or 3. When the carbon number of the alkylene group is within the above range, the resistance of the compound to hydrolysis can be further improved. At least one of the methylene groups constituting the alkylene group may be substituted with an amide group. By substituting at least one of the methylene groups constituting the alkylene group with an amide group, it is possible to sufficiently suppress the decrease in water solubility of the compound.

In the above compound, for example, in the general formula (1), L ¹ may be a methylene group or may be —CH ₂ CH ₂ CONHCH ₂ —. When L ¹ is a methylene group, the compound is represented by the following formula (1a). When L ¹ is —CH ₂ CH ₂ CONHCH ₂ —, the compound is represented by the following formula (1b).

In general formula (2), L ² represents a direct bond, a methylene group, or an alkylene group having 2 to 5 carbon atoms. In general formula (2), L ² may be an alkylene group having 2 to 10 carbon atoms. The carbon number of the alkylene group may be, for example, 2 to 8, 2 to 6, 2 to 5, 2 to 4, or 2 or 3. When the carbon number of the alkylene group is within the above range, the resistance of the compound to hydrolysis can be further improved. At least one of the methylene groups constituting the alkylene group may be substituted with an amide group. By substituting at least one of the methylene groups constituting the alkylene group with an amide group, it is possible to sufficiently suppress the decrease in water solubility of the compound.

In formula (3), L ¹ represents an amide group, a methylene group, or an alkylene group having 2 to 10 carbon atoms. In formula (3), L ¹ may be an alkylene group having 2 to 10 carbon atoms. The carbon number of the alkylene group may be, for example, 2 to 8, 2 to 6, 2 to 5, 2 to 4, or 2 or 3. When the carbon number of the alkylene group is within the above range, the resistance of the compound to hydrolysis can be further improved. At least one of the methylene groups constituting the alkylene group may be substituted with an amide group. By substituting at least one of the methylene groups constituting the alkylene group with an amide group, it is possible to sufficiently suppress the decrease in water solubility of the compound.

In the above compound, for example, in the general formula (3), L ¹ may be a methylene group or may be —CH ₂ CH ₂ CONHCH ₂ —. When L ¹ is a methylene group, the compound is represented by the following formula (3a). When L ¹ is —CH ₂ CH ₂ CONHCH ₂ —, the above compound is represented by the following formula (3b).

In formula (4), L ² represents a direct bond, a methylene group, or an alkylene group having 2 to 5 carbon atoms. In general formula (4), L ² may be an alkylene group having 2 to 10 carbon atoms. The carbon number of the alkylene group may be, for example, 2 to 8, 2 to 6, 2 to 5, 2 to 4, or 2 or 3. When the carbon number of the alkylene group is within the above range, the resistance of the compound to hydrolysis can be further improved. At least one of the methylene groups constituting the alkylene group may be substituted with an amide group. By substituting at least one of the methylene groups constituting the alkylene group with an amide group, it is possible to sufficiently suppress the decrease in water solubility of the compound.

The compound represented by the general formula (1), the general formula (2), the general formula (3) or the general formula (4) is prepared, for example, by the method described in Examples described later or a similar method. be able to.

The present disclosure provides chain transfer agents useful in reversible addition-fragmentation chain transfer polymerization processes. One embodiment of the chain transfer agent is the compound represented by the general formula (1), the compound represented by the general formula (2), the compound represented by the general formula (3) and the general formula (4). At least one selected from the group consisting of the represented compounds is included. The chain transfer agent is either a compound represented by the general formula (1), a compound represented by the general formula (2), a compound represented by the general formula (3) or a compound represented by the general formula (4). Or only one kind may be contained, and the compound represented by the general formula (1), the compound represented by the general formula (2), the compound represented by the general formula (3) and the general formula (4) is represented. A plurality of compounds selected from the group consisting of

The compounds represented by the general formula (1), the general formula (2), the general formula (3) or the general formula (4), and the chain transfer agent described above are excellent in water solubility. When an aqueous solution containing the compound is prepared, the concentration of the aqueous solution should be, for example, 10 g/mL or more, 20 g/mL or more, 30 g/mL or more, 40 g/mL or more, or 50 g/mL or more at room temperature. You can When an aqueous solution containing the compound is prepared, the concentration of the aqueous solution may be, for example, 100 mg/L or less, or 90 mg/L or less at room temperature.

Since the compound and the chain transfer agent are excellent in water solubility, the concentration of the chain transfer agent added to the polymerization system can be widely adjusted even when the polymerization solution is an aqueous solution. That is, the content of the chain transfer agent with respect to the content of the monomer in the polymerization system can be easily adjusted, and the composition of the block copolymer can be designed more precisely. For example, it is also possible to control each unit of the block copolymer to be a multimer to tens of mer. Furthermore, since the chain transfer agent is contained in the aqueous solution at a high concentration, it is not necessary to add an organic solvent as in conventional products. Therefore, by using the above-mentioned compounds as a chain transfer agent, even a polymerizable compound having a low solubility in an organic solvent can be used as a monomer in reversible addition-fragmentation chain transfer polymerization.

The compounds represented by the general formula (1), the general formula (2), the general formula (3) or the general formula (4), and the chain transfer agent described above have excellent resistance to hydrolysis. The resistance to hydrolysis is, for example, the above compound or chain transfer agent dissolved in ultrapure water to prepare a 10 g/L aqueous solution, which is heated to 70° C. and kept for a certain period of time before and after UV spectrum. It can be confirmed by measuring the change of. When the holding time is the time when the aqueous solution is heated, the maximum holding time at which the UV spectrum does not change is, for example, 1 hour or more, 3 hours or more, 6 hours or more, 12 hours or more, or 24 hours. The above can be done. The maximum retention time without change in the UV spectrum can be, for example, less than 72 hours, or less than 48 hours.

When the compound and the chain transfer agent have excellent resistance to hydrolysis, the polymerization can be continued by the reversible addition-fragmentation chain transfer polymerization method for a long time. Therefore, the reversible addition-fragmentation chain transfer polymerization performed using the above compound or the above chain transfer agent is useful when developing living radical polymerization into industrial applications.

The chain transfer agent described above can be used in a method for producing a polymer using reversible addition-fragmentation chain transfer in an aqueous system. One embodiment of the method for producing a polymer includes a step of performing reversible addition-fragmentation chain transfer polymerization in a solution containing a monomer composition, a chain transfer agent, a polymerization initiator, and water. The chain transfer agent contains the above chain transfer agent. The above-mentioned polymer production method can also be carried out in a completely aqueous system by using the above-mentioned chain transfer agent. As used herein, the term “completely aqueous system” means a system that does not substantially contain an organic solvent. The term “substantially free from” means an amount that does not reduce the solubility of the monomer in the solution, for example, the content of the organic solvent is 10 parts by mass or less with respect to 100 parts by mass of water. It means that it does not contain an organic solvent.

The monomer composition may contain a compound having an ethylenically unsaturated bond. Examples of the compound having an ethylenically unsaturated bond include (meth)acrylic acid, (meth)acrylate, acrylamide, vinylamide, styrene, acrylonitrile and derivatives thereof. The compound having an ethylenically unsaturated bond preferably contains styrene, acrylamide, or acrylate. The compounds having an ethylenically unsaturated bond may be used alone or in combination of two or more. The compound having an ethylenically unsaturated bond may be a water-soluble compound, for example, a monomer having a functional group such as a carboxy group, a hydroxyl group and an amide group. Examples of the water-soluble compound include methacrylic acid, acrylate, hydroxyethyl methacrylate, N-isopropylacrylamide, and acrylamide. In the present specification, (meth)acrylic acid means acrylic acid or methacrylic acid, (meth)acrylate means acrylate or its corresponding methacrylate, and (meth)acrylamide means acrylamide or its corresponding methacrylic acid. Means amide.

Examples of the (meth)acrylate include methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, butyl (meth)acrylate, isopropyl (meth)acrylate, and (meth)acrylic acid. 2-hydroxyethyl etc. are mentioned. Examples of (meth)acrylamide include dimethylacrylamide, N-isopropylacrylamide, 4-acryloylmorpholine, and glucose acrylamide (N-(2-(1-((2R,3R,5S,6R)-3,4,5). -Trihydroxy-6-(hydroxymethyl)tetrahydro-2H-pyran-2-yl)-1H-1,2,3-triazol-4-yl)ethyl)acrymide, hereinafter, sometimes referred to as "GlcAAm") and the like. To be

Examples of the vinyl ester include vinyl acetate and the like. Examples of vinylamides include N-vinylacetamide. Examples of the aromatic vinyl monomer include styrene, α-methylstyrene, methyl-α-methylstyrene, vinyltoluene, divinylbenzene, and styrenesulfonic acid. Examples of vinyl cyanide monomers include acrylonitrile, methacrylonitrile, α-chloroacrylonitrile, and α-ethylacrylonitrile.

Examples of the polymerization initiator include a thermal polymerization initiator and a photopolymerization initiator. Examples of the thermal polymerization initiator include organic peroxides and azo compounds. Examples of the photopolymerization initiator include aromatic ketone compounds and benzoin compounds.

Examples of the organic peroxide include benzoyl peroxide, lauroyl peroxide, di-t-butylperoxyhexahydroterephthalate, t-butylperoxy-2-ethylhexanoate, 1,1-t-butylperoxy. -3,3,5-Trimethylcyclohexane, t-butyl peroxyisopropyl carbonate and the like can be mentioned.

Examples of the azo-based initiator include, for example, 2,2′-azobis(isobutyronitrile) (AIBN), 2,2′-azobis(2-methylbutyronitrile) (AMBN), 2,2′- Azobis(2,4-dimethylvaleronitrile) (ADVN), 1,1′-azobis(1-cyclohexanecarbonitrile) (ACHN), dimethyl-2,2′-azobisisobutyrate (MAIB), and 4, 4′-azobis(4-cyanovaleric acid) (ACVA) and the like can be mentioned.

Examples of the aromatic ketone compound include benzophenone and N,N'-tetramethyl-4,4'-diaminobenzophenone. Examples of the benzoin compound include benzoin, methylbenzoin, ethylbenzoin and the like.

The solution used in the above production method may contain other additives in addition to the monomer composition, the chain transfer agent, and water. Examples of other additives include sodium chloride and tripotassium phosphate.

The concentration of the monomer composition in the aqueous solution at the time of polymerization in the reversible addition-fragmentation chain transfer polymerization may be, for example, 1 to 96% by mass, 3 to 96% by mass, or 10 to 96% by mass. You can

The amount of the chain transfer agent used may be, for example, 0.5 to 100 mol, or 0.5 to 50 mol, based on 100 mol of the monomer. By adjusting the amount of the chain transfer agent used, the block length in producing the block copolymer can be controlled more easily. The amount of the chain transfer agent used may be appropriately adjusted within the above range, and may be, for example, 1 to 100 mol, or 1 to 50 mol with respect to 100 mol of the monomer.

The amount of the chain transfer agent used may be, for example, 1.6 to 77 parts by mass or 1.6 to 38 parts by mass with respect to 100 parts by mass of the total amount of the monomer composition. By adjusting the amount of the chain transfer agent used, the block length in producing the block copolymer can be controlled more easily. The amount of the chain transfer agent used may be appropriately adjusted within the above range, and may be, for example, 3.2 to 77 parts by mass, or 3.2 to 38 parts by mass relative to 100 parts by mass of the total amount of the monomer composition. It may be part by mass.

The amount of the polymerization initiator used may be, for example, 0.01 to 40 mol or 1 to 40 mol with respect to 100 mol of the monomer. When the amount of the polymerization initiator used is within the above range, the polymerization can be sufficiently promoted and the weight average molecular weight of the obtained polymer can be more easily adjusted.

The solution used in the above production method contains water as a solvent. The solution may further contain other solvent in addition to water, and may consist of water. Examples of other solvents include methanol and dimethylformamide. When the solution contains another solvent, the content of the other solvent may be, for example, 1% by mass or less, or 10% by mass or less, based on the total amount of water and the other solvent. You can

The number average molecular weight (Mn) of the polymer obtained by the above production method is, for example, 200 to 30,000, 200 to 20,000, 1,000 to 20,000, or 1,000 to 10,000. You can

The weight average molecular weight (Mw) of the polymer obtained by the above production method is, for example, 300 to 45,000, 300 to 30,000, 1,500 to 30,000, or 1,500 to 15,000. You can

The molecular weight dispersion (Mw/Mn) of the polymer obtained by the above production method is, for example, 1.00 to 1.50, 1.0 to 1.40, 1.0 to 1.30, 1.0 to 1. It can be set to 20, or 1.0 to 1.10. When the molecular weight dispersion of the polymer is within the above range, the polymer becomes more suitable for use in, for example, a dispersant.

The number average molecular weight and the weight average molecular weight in the present specification are values determined by gel permeation chromatography measurement, and mean polystyrene equivalent values using a calibration curve prepared by measurement using standard polystyrene.

Although some embodiments have been described above, mutual explanations can be applied to the common configuration. Further, the present disclosure is not limited to the above embodiment.

Hereinafter, the present invention will be described more specifically with reference to Examples and Comparative Examples, but the present invention is not limited to these Examples.

(Example 1)
[Synthesis of Compound Represented by Formula (1a)]
The compound represented by the formula (1a) was synthesized as shown below. First, according to the following reaction formula, a precursor (a compound represented by Precursor in the reaction formula) was synthesized.

In a container, 3 g (20 mmol) of 2,2-dimethyl-1,3-dioxolane-4-methanethiol (2,2-dimethyl-1,3-dioxolane-4-methanthiol), and 3.1 mL (22 mmol) of Triethylamine (indicated by TEA in the reaction formula) was weighed out, and 21 mL of dry dichloromethane (dryCH ₂ Cl ₂ ) was added and dissolved while stirring. Next, while cooling the container with an ice bath, 1.32 mL (22 mmol) of carbon disulfide (indicated by CS ₂ in the reaction formula) dissolved in 11 mL of dry dichloromethane was added dropwise. The solution gradually became yellow as carbon disulfide was added dropwise. After that, the reaction solution was reacted for 30 minutes while stirring while cooling the container with an ice bath. Further, the container was returned to room temperature, and the reaction solution was reacted for 1 hour while stirring.

Next, 3.1 mL (22 mmol) of TEA was further added to the solution after the reaction. While cooling the container with an ice bath, 2 mL (22 mmol) of 2-bromopropionic acid (2-Bromoproponic acid) dissolved in 11 mL of dry dichloromethane was added dropwise to the solution. After that, the reaction solution was reacted for 30 minutes while stirring while cooling the container with an ice bath. Further, the above-mentioned container was returned to room temperature and reacted for 20 minutes while stirring the reaction container.

50 mL of dichloromethane was added to the solution after the reaction to prepare an organic phase. This organic phase was washed with 50 mL of a 1% by mass hydrochloric acid aqueous solution. Washing with an aqueous hydrochloric acid solution was repeated 4 times. Next, the organic phase after washing with an aqueous hydrochloric acid solution was washed with 50 mL of ultrapure water (Milli-Q water, “Milli-Q” is a registered trademark). Washing with ultrapure water was repeated 4 times. Anhydrous sodium sulfate was added to the organic phase washed with ultrapure water, and the organic phase was dried. Then, the solid was removed from the organic phase by filtration to obtain a yellow oily crude product. A small amount of ethyl acetate was added to the obtained crude product to dissolve it, and the product was added to a large amount of hexane for reprecipitation for purification. The operation of dissolution and reprecipitation was repeated twice. Hexane in the supernatant was removed, and ethyl acetate and hexane were distilled off under reduced pressure to obtain 3.10 g of a precursor (yield: 52%).

Next, using the precursor obtained as described above, the compound represented by the formula (1a) was synthesized according to the following reaction formula.

1 g (3.37 mmol) of the above precursor and 336 mg (1.34 mmol) of pyridinium p-toluenesulfonate (PPTS) were weighed into a container and dissolved in 14 mL of methanol to prepare a methanol solution. The container was allowed to react for 18 hours while stirring the methanol solution at room temperature protected from light. Thereafter, the product is purified by reverse phase column chromatography (using a mixed solvent of water and methanol as an eluent and gradient elution was performed while adjusting the polarity), and lyophilized to obtain the compound represented by the formula (1a). 521 mg (yield: 60%) of the compound (yellow viscous substance) were obtained. The obtained compound was identified using ¹ H-NMR. FIG. 1 is a ¹ H-NMR spectrogram of a compound represented by the formula (1a).

[Water solubility evaluation]
The water solubility of the compound represented by the formula (1a) obtained as described above was evaluated. Specifically, it was visually confirmed that the above compound was gradually dissolved in ultrapure water at 25° C. and the solution became completely transparent and solid was lost. In the case of the above compound, it was visually confirmed that a 50 g/L aqueous solution could be prepared.

[Performance evaluation as a chain transfer agent: reversible addition-fragmentation chain transfer polymerization]
Using 4-acryloylmorpholine (AMP) as the monomer, the performance of the compound represented by the formula (1a) as a chain transfer agent was evaluated.

First, 4-acryloylmorpholine (AMP) was dissolved in purified water to prepare a 3.0 mol/L aqueous solution. In the obtained aqueous solution, AMP, the compound represented by the formula (1a) prepared as described above, and 2,2′-bis(2-imidazolin-2-yl)[2,2′-azobis Propane]•dihydrochloride (2,2′-Azobis(2-(2-imidazolin-2-yl)propane)dihydrochloride, manufactured by Fujifilm Wako Pure Chemical Industries, Ltd., trade name: VA-044) To 100:1:0.01 to obtain a reaction solution. After the reaction solution was heated to 70° C. to generate radicals from the initiator, reversible addition-fragmentation chain transfer polymerization was carried out for 1 hour under the condition of 70° C.

Separately from the above, AMP was dissolved in purified water to prepare a 3.0 mol/L aqueous solution. In the obtained aqueous solution, AMP, the compound represented by the formula (1a) prepared as described above, and 2,2′-bis(2-imidazolin-2-yl)[2,2′-azobis Propane]•dihydrochloride (manufactured by Fuji Film Wako Pure Chemical Industries, Ltd., trade name: VA-044) was dissolved in a molar ratio of 10:1:0.01 to obtain a reaction solution. After the reaction solution was heated to 70° C. to generate radicals from the initiator, reversible addition-fragmentation chain transfer polymerization was carried out for 1 hour under the condition of 70° C.

The conversion rate in each polymerization reaction was evaluated by measurement using ¹ H-NMR. Furthermore, the number average molecular weight (Mn), the weight average molecular weight (Mw), and the molecular weight dispersion (Mw/Mn) of the polymer and block copolymer obtained after the polymerization reaction were measured. The results are shown in Table 1.

(Example 2)
[Synthesis of Compound Represented by Formula (1b)]
A compound represented by the formula (1b) was synthesized. First, compound 1 was synthesized according to the following reaction formula.

In a container, weigh 500 mg (3.37 mmol) of 3-(acetylthio)propionic acid and 450 mg (3.43 mmol) of 2,2-dimethyl-1,3-dioxolane-4-methanamine, and dry 35 mL of methanol. (Indicated by dryMeOH in the reaction formula) was added and dissolved. Next, as a condensing agent, 943 mg (3.41 mmol) of 4-(4,6-dimethoxy-1,3,5-triazin-2-yl)-4-methylmorpholinium chloride n hydrate (reaction formula (Indicated by DMT-MM) was added, and the reaction was carried out at room temperature for 3 hours while stirring the reaction solution.

After completion of the reaction, the solvent was distilled off from the reaction solution under reduced pressure. Next, 10 mL of dichloromethane was added to prepare an organic phase, which was washed with a 1% by mass hydrochloric acid aqueous solution. An organic phase was obtained by a liquid separation operation. Anhydrous sodium sulfate was added to the organic phase, and the organic phase was dried. Then, the solid was removed from the organic phase by filtration to obtain a crude product. The obtained crude product was purified by silica gel chromatography using chloroform as an eluent to obtain Compound 1 (yield: 86%).

Next, using the compound 1 obtained as described above, the compound 2 (compound having a thiol group) was synthesized according to the following reaction formula.

In a container, 4.5 g (17.0 mmol) of Compound 1 and 920 mg (17.0 mmol) of sodium methoxide were weighed and dissolved in 50 mL of dry methanol. The reaction was carried out at room temperature for 2 hours while stirring the reaction solution. After the reaction was completed, 3.8 g of an ion exchange resin (Amberlite, manufactured by Dow Chemical Co., Ltd., trade name) was added, and after 5 minutes, solids were removed by filtration. The obtained liquid phase was distilled under reduced pressure and dried in vacuum to obtain compound 2.

Using the compound 2 obtained as described above, the compound 3 was synthesized according to the following reaction formula.

3.21 g (14.6 mmol) of compound 2 and 592 mg (14.8 mmol) of sodium hydroxide were weighed in a container and dissolved in 12 mL of purified water. The reaction was carried out at room temperature for 15 minutes while stirring half of the solution. Next, after adding 1.06 mL (17.5 mmol) of carbon disulfide (indicated by CS ₂ in the reaction formula), 1 mL of acetone was further added, the reaction system was cooled, and the reaction was performed at 0° C. The reaction was carried out while stirring the solution, and it was confirmed that the reaction solution was colored orange.

To the orange-colored reaction solution, 1.57 mL (17.5 mmol) of 2-bromopropanoic acid was added, and it was confirmed that the reaction solution changed to a yellow suspension. 1.4 mL of sodium hydroxide aqueous solution (12.5 mol/L) was added to the suspension, and the reaction was carried out at room temperature for 24 hours while stirring the suspension. When the reaction system was cooled to 0°C, 1N hydrochloric acid was added, and it was confirmed that an oily precipitate was formed. Then, 50 mL of dichloromethane was added and liquid separation operation was performed to obtain an organic phase.

Anhydrous sodium sulfate was added to the obtained organic phase to dry the organic phase. Then, the solid was removed from the organic phase by filtration to obtain a crude product. The obtained crude product was purified by silica gel chromatography (using a mixed solvent of ethyl acetate and hexane as an eluent to elute with gradient while adjusting the polarity) to give compound 3 (yield: 30 %) was obtained.

Using the compound 3 obtained as described above, the compound represented by the formula (1b) was synthesized according to the following reaction formula.

In a container, 3.5 g (9.52 mmol) of Compound 3 was measured and dispersed in 100 mL of purified water to obtain a dispersion liquid. To the obtained dispersion liquid, 10 μL of a hydrochloric acid aqueous solution was added to adjust the pH of the aqueous solution to 4.0. After adjusting the pH, the reaction was carried out at room temperature for 24 hours while stirring the dispersion liquid. After completion of the reaction, the suspension was distilled under reduced pressure to obtain a concentrated liquid. The obtained concentrated solution was purified by reverse phase column chromatography (using a mixed solvent of water and methanol as an eluent and gradient elution was performed while adjusting the polarity) to obtain a compound represented by the formula (1b). Compound (yield: 90%) was obtained. The obtained compound was identified using ¹ H-NMR and ¹³ C-NMR. FIG. 2 is a ¹ H-NMR spectrogram of the compound represented by the formula (1b). FIG. 3 is a ¹³ C-NMR spectrogram of the compound represented by the formula (1b).

[Water solubility evaluation]
The water solubility of the compound represented by the formula (1b) obtained as described above was evaluated. Specifically, it was visually confirmed that the above compound was gradually dissolved in ultrapure water at 25° C. and the solution became completely transparent and solid was lost. In the case of the above compound, it was confirmed that an aqueous solution of 50 g/L could be prepared.

[Evaluation of hydrolysis resistance]
The hydrolysis resistance of the compound represented by the formula (1b) obtained as described above was evaluated. First, the above compound was dissolved in ultrapure water to prepare a 10 g/L aqueous solution. The prepared aqueous solution was heated to 70° C., allowed to stand in an environment of 70° C. for 1 hour, 3 hours, 6 hours, 12 hours, and 24 hours, and then returned to room temperature. The solution that had been heated and returned to room temperature was used as a sample, and the UV resistance was measured to evaluate the hydrolysis resistance of the above compound. The results are shown in Fig. 4.

FIG. 4 is a graph showing the results of UV spectrum measurement. In the graph shown in FIG. 4, a peak observed near a wavelength of 300 nm shows absorption corresponding to a trithiocarbonyl group. As shown in FIG. 4, it was confirmed that the above compound had no change in absorption spectrum even after being placed in a water environment at 70° C. for 24 hours, and was also very excellent in hydrolysis resistance.

[Performance evaluation as a chain transfer agent: reversible addition-fragmentation chain transfer polymerization]
As a monomer, glucose acrylamide (N-(2-(1-((2R,3R,5S,6R)-3,4,5-trihydroxy-6-(hydroxymethyl)tetrahydro-2H-pyran-2-yl)-1H) -1,2,3-triazol-4-yl)ethyl)acrylamide, glucose-introduced acrylamide, hereinafter referred to as "GlcAAm"), 4-acryloylmorpholine (AMP), and N,N-dimethylacrylamide (DMA). Was used to evaluate the performance of the compound represented by the formula (1b) as a chain transfer agent.

First, as the first step, GlcAAm was dissolved in purified water to prepare a 1.5 mol/L aqueous solution. In the obtained aqueous solution, GlcAAm, the compound represented by the formula (1b), and 2,2′-bis(2-imidazolin-2-yl)[2,2′-azobispropane] as a thermal polymerization initiator. Dihydrochloride (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd., trade name: VA-044) was dissolved in a molar ratio of 10:1:0.02 to obtain a reaction solution. After the reaction solution was heated to 70° C. to generate radicals from the initiator, reversible addition-fragmentation chain transfer polymerization was carried out for 2 hours at 70° C.

Next, 4-acryloylmorpholine (AMP) was added to the above reaction solution so that the concentration of 4-acryloylmorpholine (AMP) was 1.2 mol/L. 4-Acryloylmorpholine (AMP), the compound represented by the formula (1b), and the thermal polymerization initiator are represented by the formula (1) so that the molar ratio becomes 10:1:0.02. The compound and 2,2′-bis(2-imidazolin-2-yl)[2,2′-azobispropane]·dihydrochloride were further added to obtain a reaction solution for carrying out the second-stage polymerization. Similarly to the above, the reaction solution was heated to 70° C. to generate radicals from the initiator, and then reversible addition-fragmentation chain transfer polymerization was performed for 2 hours under the condition of 70° C.

N,N-Dimethylacrylamide (DMA) was added to the reaction solution after completion of the second-stage polymerization so that the concentration of N,N-dimethylacrylamide (DMA) was 1.0 mol/L. N,N-dimethylacrylamide (DMA), the compound represented by the formula (1b) and the thermal polymerization initiator are represented by the formula (1b) so that the molar ratio becomes 10:1:0.02. Compound and 2,2'-bis(2-imidazolin-2-yl)[2,2'-azobispropane] dihydrochloride are further added to obtain a reaction solution for carrying out the third stage polymerization. It was Similarly to the above, the reaction solution was heated to 70° C. to generate radicals from the initiator, and then reversible addition-fragmentation chain transfer polymerization was performed for 2 hours under the condition of 70° C.

Thereafter, reversible addition-fragmentation chain transfer polymerization was carried out for 2 hours in the same manner as in the above-mentioned method except that the monomer species, the monomer concentrations, and the charging ratios shown in Table 2 were adjusted. To prepare a block copolymer. In any of the first to tenth steps, the charge was adjusted so that the polymer and each block constituting the block copolymer would grow by the amount of the monomer decamer.

The conversion rate in each polymerization reaction was evaluated by measurement using ¹ H-NMR. Furthermore, the number average molecular weight (Mn), the weight average molecular weight (Mw), and the molecular weight dispersion (Mw/Mn) of the polymer and the block copolymer obtained after the polymerization reaction were measured. The results are shown in Table 2.

From the results shown in Table 1, it was confirmed that the conversion rate was 99% or more in any of the first to 10th stages. Further, it was confirmed that the molecular weight dispersion of the obtained polymer was in the range of 1.15 to 1.36, and the molecular weight dispersion was suppressed to be sufficiently low. From these results, it was confirmed that the compound represented by the formula (1b) is useful as a chain transfer agent and can perform reversible addition-fragmentation chain transfer polymerization in a complete water system with high accuracy.

In addition, it was confirmed that the compound represented by the formula (1b) had high water solubility, and the adjustment range of the concentration of the chain transfer agent in the reaction aqueous solution was wider than that of the conventional chain transfer agent. From this, it was confirmed that the composition of the block copolymer can be easily controlled in a relatively short unit such as 10-mer units.

(Example 3)
[Synthesis of Compound Represented by Formula (3a)]
The compound represented by the formula (3a) was synthesized as shown below. First, according to the following reaction formula, a precursor (a compound represented by Precursor in the reaction formula) was synthesized.

In a container, 3 g (20 mmol) of 2,2-dimethyl-1,3-dioxolane-4-methanethiol and 3.1 mL (22 mmol) of triethylamine (indicated by TEA in the reaction formula) were weighed and dried in 21 mL. Dichloromethane (dryCH ₂ Cl ₂ ) was added and dissolved with stirring. Next, while cooling the container with an ice bath, 1.32 mL (22 mmol) of carbon disulfide (indicated by CS ₂ in the reaction formula) dissolved in 11 mL of dry dichloromethane was added dropwise. The solution gradually became yellow as carbon disulfide was added dropwise. After that, the reaction solution was reacted for 30 minutes while stirring while cooling the container with an ice bath. Further, the container was returned to room temperature, and the reaction solution was reacted for 1 hour while stirring.

Next, 2.26 g (14.9 mmol) of 2-bromopropionicamide (2-Bromopropionicamide) dissolved in 50 mL of dry dichloromethane was added dropwise to the above solution while cooling the container with an ice bath. After that, the reaction solution was reacted for 30 minutes while stirring while cooling the container with an ice bath. Further, the above-mentioned container was returned to room temperature, and the reaction was performed for 28 hours while stirring the reaction container.

After completion of the reaction, volatile components were distilled off from the solution under reduced pressure to obtain a crude product. The obtained crude product was subjected to silica gel chromatography (a mixed solvent of ethyl acetate and hexane at a volume ratio of 1:1 was used as an eluent) to fractionate containing a precursor (Rf value was 0.2. Fraction) was collected. The solvent was distilled off under reduced pressure from the obtained fraction. Next, 10 mL of dichloromethane was added to prepare an organic phase, which was washed three times with ultrapure water. An organic phase was obtained by a liquid separation operation. Anhydrous sodium sulfate was added to the organic phase, and the organic phase was dried. Then, the solid was removed from the organic phase by filtration, and the solvent was distilled off under reduced pressure to obtain 1.08 g of a precursor (yield: 27%).

Next, using the precursor obtained as described above, the compound represented by the formula (3a) was synthesized according to the following reaction formula.

300 mg (1.02 mmol) of the above precursor and 3 mL of a hydrochloric acid aqueous solution (concentration: 0.1 M) were weighed into a container to prepare a suspension. The suspension was reacted for 6 hours while stirring. The suspension was colored yellow as the reaction proceeded. Next, the reaction solution was neutralized using an ion exchange resin. After removing the ion exchange resin, the neutralized solution was freeze-dried to obtain the compound represented by the formula (3a) (yellow solid). FIG. 5 is a ¹ H-NMR spectrogram of the compound represented by formula (3a).

[Water solubility evaluation]
The water solubility of the compound represented by the formula (3a) obtained as described above was evaluated. Specifically, it was visually confirmed that the above compound was gradually dissolved in ultrapure water at 25° C. and the solution became completely transparent and solid was lost. In the case of the above compound, it was visually confirmed that a 50 g/L aqueous solution could be prepared.

The compound represented by the formula (3a) has a trithiocarbonyl group and thus can function as a chain transfer agent.

According to the present disclosure, it is possible to provide a compound that has excellent water solubility and can be used as a chain transfer agent. The present disclosure can also provide a chain transfer agent having excellent water solubility. The present disclosure can also provide a method for producing a polymer using the above-mentioned chain transfer agent.

Claims (7)

A compound represented by the following general formula (1), the following general formula (2), the following general formula (3) or the following general formula (4).

[In General Formula (1) and General Formula (3), L ¹ represents an amide group, a methylene group, or an alkylene group having 2 to 10 carbon atoms, and at least one of the methylene groups constituting the alkylene group is an amide group. May be replaced with
In formulas (2) and (4), L ² represents a direct bond, a methylene group, or an alkylene group having 2 to 10 carbon atoms, and at least one of the methylene groups constituting the alkylene group is an amide group. It may be substituted. ] In the general formulas (1) and (3), L ¹ represents an alkylene group having 2 to 10 carbon atoms, at least one of the methylene groups constituting the alkylene group is substituted with an amide group,
In the general formulas (2) and (4), L ² represents an alkylene group having 2 to 10 carbon atoms, and at least one of methylene groups constituting the alkylene group is substituted with an amide group. The compound according to 1. In general formula (1) and general formula (3), L ¹ is a methylene group or —CH ₂ CH ₂ CONHCH ₂ —, and in general formula (2) and general formula (4), L ² is methylene. The compound according to claim 1, which is a group or —CH ₂ CH ₂ CONHCH ₂ —. A group consisting of a compound represented by the following general formula (1), a compound represented by the following general formula (2), a compound represented by the following general formula (3) and a compound represented by the following general formula (4). A chain transfer agent containing at least one selected from the group consisting of:

[In General Formula (1) and General Formula (3), L ¹ represents an amide group, a methylene group, or an alkylene group having 2 to 10 carbon atoms, and at least one of the methylene groups constituting the alkylene group is an amide group. May be replaced with
In formulas (2) and (4), L ² represents a direct bond, a methylene group, or an alkylene group having 2 to 10 carbon atoms, and at least one of the methylene groups constituting the alkylene group is an amide group. It may be substituted. ] In the general formulas (1) and (3), L ¹ represents an alkylene group having 2 to 10 carbon atoms, at least one of the methylene groups constituting the alkylene group is substituted with an amide group,
In the general formulas (2) and (4), L ² represents an alkylene group having 2 to 10 carbon atoms, and at least one of methylene groups constituting the alkylene group is substituted with an amide group. 4. The chain transfer agent according to item 4. In general formula (1) and general formula (3), L ¹ is a methylene group or —CH ₂ CH ₂ CONHCH ₂ —, and in general formula (2) and general formula (4), L ² is methylene. The chain transfer agent according to claim 4, which is a group or —CH ₂ CH ₂ CONHCH ₂ —. In a solution containing a monomer composition containing a compound having an ethylenically unsaturated bond, a chain transfer agent, and water, including a step of performing reversible addition-fragmentation chain transfer polymerization,
A method for producing a polymer, wherein the chain transfer agent contains the chain transfer agent according to any one of claims 4 to 6.

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