Novel dicarboxylic acids and dicarboxylic acid esters with an isocyanurate skeleton

Abstract

To solve the problem in which introducing isocyanurate skeletons into resin systems, such as polyester and polyamide, polymerized from dicarboxylic acid monomers, is desired for the expression of characteristics such as heat resistance, mechanical strength, moisture resistance, and electrical properties, but there are only a limited number of reports of isocyanurate compounds with carboxyl groups, and to provide novel dicarboxylic acids and dicarboxylates with isocyanurate skeletons.SOLUTION: The foregoing problem is solved by a compound represented by the following formula (1) (where A is a divalent organic group directly bonded, or terminated with a carbon atom, R is a hydrogen atom or a hydrocarbon group, and R1 is a hydrogen atom or a monovalent organic group).SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to novel dicarboxylic acids and dicarboxylic acid esters having an isocyanurate skeleton. [Background technology]

[0002] Isocyanurate compounds have traditionally been used as resin modifiers and crosslinking agents in the field of resin materials. Because they have a rigid, highly stackable central skeleton, their incorporation into resin materials can impart unprecedented physical properties, such as improved mechanical strength, heat resistance, moisture resistance, and hydrolysis resistance.

[0003] Patent Document 1 shows that combining polyphenylene ether with an isocyanurate crosslinking agent exhibits excellent electrical properties. Patent Document 2 discloses an isocyanurate compound having a glycidyl group, and describes that combining it with an epoxy resin can impart good heat resistance and mechanical properties. Furthermore, cases have been reported in which an isocyanurate skeleton is directly introduced into the main skeleton of a resin as a monomer, rather than just as a crosslinking agent or resin modifier.

[0004] The diamine compound having an isocyanurate skeleton described in Patent Document 3 can be used as a raw material (monomer) for polyimide resins, and it is expected that unprecedented physical properties can be achieved by directly introducing an isocyanurate skeleton into a polyimide skeleton. In addition, the diamine compound can also be used as a curing agent for epoxy resins.

[0005] Patent Document 4 also describes a diamine monomer having an isocyanurate skeleton, shows the use of a polyimide obtained using the monomer as a liquid crystal aligning agent, and discloses the unique physical properties of polyimides containing an isocyanurate skeleton. As such, diamine monomers having an isocyanurate skeleton are essential for introducing specific structures into resins such as polyamides, polyimides, and polybenzoxazoles, and various examples have been reported. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] WO2020 / 196718 [Patent Document 2] Patent No. 6512012 [Patent Document 3] Patent Publication No. 2014-58452 [Patent Document 4] Patent No. 4868167 Summary of the Invention [Problem to be solved by the invention]

[0007] On the other hand, dicarboxylic acids and dicarboxylic acid esters are also important in introducing specific structures into resins. For example, dicarboxylic acids and dicarboxylic acid esters can be used to obtain resins such as polyesters and polyamides. The introduction of an isocyanurate skeleton into these resin systems is desirable from the viewpoint of the expression of properties such as heat resistance, mechanical strength, moisture resistance, and electrical properties. However, there have been only limited reports of isocyanurate compounds with carboxy groups.

[0008] In view of the above circumstances, an object of the present invention is to provide a novel dicarboxylic acid and dicarboxylic acid ester having an isocyanurate skeleton. [Means for solving the problem]

[0009] The present invention can solve the above problems by providing the following novel dicarboxylic acids and dicarboxylic acid esters containing an isocyanurate skeleton.

[0010] [1]. A compound represented by general formula (1). In the formula, A is a divalent organic group that is directly bonded or terminated in a carbon atom, R is a hydrogen atom or a hydrocarbon group, and R1 is a hydrogen atom or a monovalent organic group. [ka]

[0011] [2] The compound according to [1], wherein A in general formula (1) is a direct bond.

[0012] [3] The compound according to [1] or [2], wherein R in the general formula (1) is a hydrogen atom or a hydrocarbon group having 5 or less carbon atoms.

[0013] [4] The compound according to any one of [1] to [3], wherein R1 in general formula (1) is a monovalent hydrocarbon group having 60 or less carbon atoms. [Effects of the Invention]

[0014] The dicarboxylic acid compound having an isocyanurate skeleton (isocyanuric acid skeleton) of the present invention can impart the rigidity characteristic of isocyanurates to urethanes, polyesters, polycarbonates, etc. In addition, the presence of a carbon-carbon triple bond not only imparts further rigidity, but also allows for thermal crosslinking and functions as a reaction site for hydrosilylation, etc. Furthermore, the substituent on the isocyanurate ring (R1 in general formula (1)) can be varied in various ways, significantly expanding the options for monomers when synthesizing resins with various properties. DETAILED DESCRIPTION OF THE INVENTION

[0015] Although the embodiments of the present invention are described below, the present invention is not limited thereto. All academic documents and patent documents described in this specification are incorporated herein by reference. Unless otherwise specified in this specification, "A to B" representing a numerical range means "A or more (including A and greater than A) and B or less (including B and less than B)."

[0016] The diol compound having an isocyanurate skeleton of the present invention has two of the three nitrogen atoms on the isocyanurate ring bonded to phenyl groups, and a substituent having a terminal carboxyl group bonded to the phenyl group via a carbon-carbon triple bond. Furthermore, a hydrogen atom or a substituent is bonded to the remaining nitrogen atom on the isocyanurate ring, resulting in a dicarboxylic acid and a dicarboxylic acid ester represented by general formula (1). In the formula, A is directly bonded or a divalent organic group that terminates in a carbon atom, R is a hydrogen atom or a hydrocarbon group, and R is a hydrogen atom or a monovalent organic group. Here, "A being directly bonded" means that the carbonyl carbon of the carboxylic acid and the carboxylic acid ester is directly bonded to a carbon that constitutes a carbon-carbon triple bond (alkyne). Furthermore, "A being terminated by a carbon atom" means that it is bonded to the carbonyl carbon and the alkyne via a carbon atom (not via a heteroatom). [ka]

[0017] An example of a synthesis scheme for obtaining the dicarboxylic acid compound of the present invention is shown in (Synthesis Scheme). In reaction (A), a solution of an isocyanate compound (1-1) such as 3-bromophenyl isocyanate, 4-bromophenyl isocyanate, or 4-chlorophenyl isocyanate dissolved in a solvent is added dropwise to a cyanate salt dispersed in a solvent. After the reaction, the solvent is distilled off under reduced pressure, and the resulting mixture is separated several times using an appropriate organic solvent and water. The aqueous layer is then recovered and a Brønsted acid is added to precipitate the isocyanurate compound (1-2). After the product is recovered, it may be further purified, such as by washing or recrystallization. [ka]

[0018] Examples of solvents for this reaction and the dropping solution include N,N-dimethylformamide, N,N-dimethylacetamide, N-methyl-2-pyrrolidone, 1,3-dimethyl-2-imidazolidinone, 3-methoxy-N,N-dimethylpropanamide, 3-methoxy-N,N-dibutylpropanamide, dimethyl sulfoxide, and 1,4-dioxane, with N,N-dimethylformamide, N,N-dimethylacetamide, N-methyl-2-pyrrolidone, and dimethyl sulfoxide being preferred, and N,N-dimethylformamide being particularly preferred.

[0019] Examples of cyanate that can be used include potassium cyanate and sodium cyanate. The reaction is carried out at a temperature of 25°C to 150°C, preferably 40°C to 120°C, and more preferably 60°C to 100°C. The reaction time is 10 minutes to 120 minutes, preferably 15 minutes to 60 minutes. After the dropwise addition, the reaction is continued for 10 minutes to 6 hours, preferably 15 minutes to 3 hours. The organic solvent used for separation is not particularly limited, but hexane, toluene, ethyl acetate, diethyl ether, methylene chloride, chloroform, etc. can be used, and a combination of two or more of these can also be used. Examples of acids added to the aqueous layer after separation include hydrochloric acid, sulfuric acid, and acetic acid, with hydrochloric acid being preferred. When recrystallizing the obtained solid, alcohols such as methanol, ethanol, and 2-propanol, and esters such as ethyl acetate and butyl acetate can be used. These can be combined with hydrocarbons such as hexane as a poor solvent, with ethanol being particularly preferred.

[0020] If R1 is a hydrogen atom, step (B) of introducing the substituent R1 can be omitted and the process can proceed to step (C) of the cross-coupling reaction. Here, the case where R is other than a hydrogen atom will be described. Any known organic synthesis method can be used to introduce the substituent R1. As an example, the substituent R1 can be introduced by dissolving the isocyanurate compound (1-2) and a base in an appropriate solvent, adding 1.0 to 2.0 equivalents, preferably 1.1 to 1.5 equivalents, of the compound RX, which is the source of the substituent R1, relative to the isocyanurate, and carrying out the reaction.

[0021] Here, R is a monovalent organic group, and X is a leaving group of any type, including chloro, bromo, iodo, tosyloxy, mesyloxy, and trifluoromethanesulfonyloxy. The substituent R1 is a monovalent organic group, and is not particularly limited, including alkyl groups such as methyl, ethyl, n-propyl, n-butyl, s-butyl, and t-butyl, and hydrocarbon groups containing carbon-carbon double or triple bonds such as allyl, homoallyl, cinnamyl, and propargyl. Heteroatom-containing substituents such as glycidyl and oxetanyl are also acceptable.

[0022] The substituent R1 can be varied widely, and by changing the substituent, it is possible to achieve the desired material properties, resin polymerizability, etc. When the substituent R1 is a hydrogen atom (when no substituent is substantially introduced), the NH bond of the isocyanurate ring functions as an acid. Therefore, it is also possible to use the dicarboxylic acid and dicarboxylic acid ester compounds of the present invention without actively introducing the substituent R1, with the NH bond of the isocyanurate ring as an acid group.

[0023] Furthermore, it is also possible to introduce an isocyanurate structure into the main skeleton of a resin as a monomer without introducing the substituent R1, and then introduce the substituent R1 or use it as a crosslinking point. In the present invention, the advantages of using an isocyanurate ring rather than a benzene ring as the central skeleton of a dicarboxylic acid and a dicarboxylic acid ester are not only the rigidity and strong stacking ability unique to isocyanurates, but also the ease of introducing a substituent and the function as an acid group.

[0024] The base is not particularly limited, and examples thereof include organic bases such as triethylamine, diisopropylethylamine, pyridine, quinoline, isoquinoline, 3,5-lutidine, 2,6-lutidine, and picoline, and inorganic bases such as sodium carbonate, potassium carbonate, sodium hydroxide, potassium hydroxide, and sodium hydride. The base can be used in an amount of 1.0 to 3.0 equivalents, preferably 1.1 to 2.0 equivalents, relative to the substrate (1-2).

[0025] The solvent used in this reaction is not particularly limited, but examples include tetrahydrofuran, 1,4-dioxane, acetone, N,N-dimethylformamide, N,N-dimethylacetamide, N-methyl-2-pyrrolidone, 1,3-dimethyl-2-imidazolidinone, 3-methoxy-N,N-dimethylpropanamide, 3-methoxy-N,N-dibutylpropanamide, and dimethyl sulfoxide. The reaction can be carried out at a temperature of 20°C to 120°C, preferably 40°C to 100°C, and more preferably 50°C to 90°C. The reaction time can be 1 hour to 12 hours, and preferably 1 hour to 6 hours.

[0026] After the reaction, the solvent may be removed by distillation under reduced pressure, and an appropriate purification procedure may be carried out. For example, purification by separation, recrystallization, or column chromatography may be carried out alone or in combination. Alternatively, the reaction may proceed to the next reaction without purification. In this case, the crude product may be obtained by distillation under reduced pressure, and then charged into the cross-coupling reaction. Alternatively, the solvent may not be removed by distillation under reduced pressure, and the substrates and catalyst required for the cross-coupling reaction may be newly charged into the same reaction vessel.

[0027] Step (C) can be carried out by the Sonogashira cross-coupling reaction. The substrate (1-3) and a carboxylic acid or ester containing a carbon-carbon triple bond are dissolved in a solvent, and the cross-coupling reaction proceeds by adding a palladium catalyst, a copper catalyst, and an amine compound.

[0028] As the amine compound, triethylamine, diisopropylethylamine, diethylamine, etc. can be preferably used, and the amount added is generally in large excess relative to the substrate, specifically 10 equivalents or more relative to the substrate.

[0029] Suitable palladium catalysts include tetrakis(triphenylphosphine)palladium and bis(triphenylphosphine)palladium dichloride. Copper(I) halides can be used as copper catalysts, with copper(I) iodide being particularly preferred. The solvent is not particularly limited, but the above-mentioned amine compounds may be used as solvents. In this case, if the solubility of the substrate is insufficient, a solvent that dissolves the substrate and does not inhibit the reaction may be added as a co-solvent.

[0030] Specific examples include tetrahydrofuran, 1,4-dioxane, acetone, N,N-dimethylformamide, N,N-dimethylacetamide, N-methyl-2-pyrrolidone, 1,3-dimethyl-2-imidazolidinone, 3-methoxy-N,N-dimethylpropanamide, 3-methoxy-N,N-dibutylpropanamide, and dimethyl sulfoxide. The reaction can be carried out at a temperature of 20°C to 150°C for a reaction time of 1 hour to 48 hours, preferably 1 hour to 12 hours. After the reaction, the solvent is distilled off under reduced pressure, and then a separation operation is carried out to remove the remaining metal catalyst and amine components, followed by purification by recrystallization and / or column chromatography.

[0031] The structure of A in general formula (1) is determined based on the structure of the carboxylic acid substrate selected in this step. The carboxylic acid substrate to be selected may be any carboxylic acid having a terminal alkyne, such as propiolic acid, 3-butynoic acid, 2-hydroxy-3-butynoic acid, or ethyl 2-hydroxy-3-butynoate. Furthermore, esters (R≠H) of the above carboxylic acids can also serve as substrates. Examples of R include hydrocarbon groups such as methyl, ethyl, n-propyl, n-butyl, t-butyl, and phenyl groups, as well as aryl groups such as benzyl and allyl groups, with hydrocarbon groups having 5 or fewer carbon atoms being preferred.

[0032] (Application) The dicarboxylic acid compound of the present invention can be used as a polymerization monomer to impart unprecedented properties to any resin material, such as thermoplastic resins, thermosetting resins, cation-curable resins, anion-curable resins, radical-curable resins, etc. By introducing the rigid structure of isocyanurate and alkyne into the main chain skeleton of the resin, it is possible to improve mechanical strength, heat resistance, chemical resistance, hydrolysis resistance, etc.

[0033] When the diol compound of the present invention is used as a polymerizable monomer for a resin, the type of resin is not particularly limited. However, it is particularly suitable for use with resins that can generally be polymerized using dicarboxylic acid compounds as monomers. Examples of such resins include polyesters, polyamides, and resins containing these as part of their repeating units. Since polyesters can also be polymerized by transesterification of dicarboxylic acid ester compounds and diol compounds, dicarboxylic acid ester compounds are also included in the scope of the present invention. Furthermore, since the dicarboxylic acids and dicarboxylic acid esters of the present invention have carbon-carbon triple bonds, they can also be incorporated into siloxane resins by hydrosilylation reactions.

[0034] The dicarboxylic acid compound of the present invention or a resin obtained using the compound can be used in various applications, such as adhesives, pressure-sensitive adhesives, electronic materials, insulating materials (including printed circuit boards, wire coatings, etc.), high-voltage insulating materials, interlayer insulating films, TFT passivation films, TFT gate insulating films, TFT interlayer insulating films, TFT transparent planarizing films, insulating packings, insulating coating materials, adhesives, highly heat-resistant adhesives, highly heat-dissipating adhesives, optical adhesives, adhesives for LED elements, adhesives for various substrates, adhesives for heat sinks, paints, UV powder paints, inks, colored inks, UV inkjet inks, coating materials (including hard coats, sheets, films, release paper coats, optical disk coats, and optical fiber coats), and molding materials (including sheets, films, FRP, etc.). ), sealing materials, potting materials, encapsulating materials, encapsulating materials for light-emitting diodes, liquid crystal sealants, sealants for display devices, encapsulating materials for electrical materials, encapsulating materials for various solar cells, high-heat-resistant sealants, resist materials, liquid resist materials, colored resists, dry film resist materials, solder resist materials, binder resins for color filters, transparent planarizing materials for color filters, binder resins for black matrices, photospacer materials for liquid crystal cells, transparent encapsulating materials for OLED elements, photolithography, materials for solar cells, materials for fuel cells, display materials, recording materials, vibration-proof materials, waterproof materials, moisture-proof materials, photosensitive drums for copiers, solid electrolytes for batteries, etc. The isocyanuric acid skeleton-containing polymer may also be used as an additive to other resins, etc. Needless to say, the uses are not limited to those listed below. [Example]

[0035] The present invention will be specifically explained below with reference to examples, but the present invention is not limited to these examples.

[0036] Example 1 A reaction vessel was charged with 1 L of N,N-dimethylformamide (DMF) and 48 g of potassium cyanate and heated to 75°C. A solution of 198 g of 4-bromophenyl isocyanate dissolved in 500 mL of DMF was added dropwise over 30 minutes using a dropping funnel. After the addition, the mixture was stirred for 1 hour to complete the reaction. The DMF was removed under reduced pressure, and 1 L of ethyl acetate and 3 L of water were added. Concentrated hydrochloric acid was added to the aqueous layer, and the precipitate was collected and recrystallized from ethanol to yield 178 g of white crystals (2).

[0037] A flask was charged with 21.9 g of the above white crystals (2), 8.41 g of propiolic acid, 3.51 g of bis(triphenylphosphine)palladium(II) dichloride, 1.9 g of copper(I) iodide, 100 mL of DMF, and 500 mL of triethylamine, and the mixture was stirred at 80°C for 8 hours under a nitrogen atmosphere to react. After the reaction was completed, the solvent was removed under reduced pressure, and the mixture was separated into water and ethyl acetate, and the organic layer was concentrated. The obtained crude product was recrystallized from ethanol to obtain 16.3 g of diol compound (3) represented by the following formula: [ka] [ka]

[0038] Example 2 A reaction vessel was charged with 1 L of N,N-dimethylformamide (DMF) and 48 g of potassium cyanate and heated to 75°C. A solution of 198 g of 3-bromophenyl isocyanate dissolved in 500 mL of DMF was added dropwise over 30 minutes using a dropping funnel. After the addition, the mixture was stirred for 1 hour to complete the reaction. The DMF was removed under reduced pressure, and 1 L of ethyl acetate and 3 L of water were added. Concentrated hydrochloric acid was added to the aqueous layer, and the precipitate was collected and recrystallized from ethanol to yield 169 g of white crystals (4).

[0039] A flask was charged with 21.9 g of the above white crystals (4), 8.41 g of propiolic acid, 3.51 g of bis(triphenylphosphine)palladium(II) dichloride, 1.9 g of copper(I) iodide, 100 mL of DMF, and 500 mL of triethylamine, and the mixture was stirred under a nitrogen atmosphere at 80°C for 8 hours to react. After completion of the reaction, the solvent was removed under reduced pressure, and the mixture was separated into water and ethyl acetate, and the organic layer was concentrated. The obtained solid was recrystallized from ethanol to obtain 14.7 g of diol compound (5) represented by the following formula. [ka] [ka]

[0040] Example 3 A flask was charged with 21.9 g of compound (2) obtained in Example 1, 10.08 g of methyl propiolate, 3.51 g of bis(triphenylphosphine)palladium(II) dichloride, 1.9 g of copper(I) iodide, 100 mL of DMF, and 500 mL of triethylamine, and the mixture was stirred at 80°C for 8 hours under a nitrogen atmosphere to react. After completion of the reaction, the solvent was removed under reduced pressure, and the mixture was separated into water and ethyl acetate, and the organic layer was concentrated. The obtained crude product was recrystallized from ethanol to obtain 18.8 g of dicarboxylic acid ester compound (6) represented by the following formula: [ka]

[0041] Example 4 A flask was charged with 21.9 g of compound (2) obtained in Example 1, 10.08 g of methyl propiolate, 3.51 g of bis(triphenylphosphine)palladium(II) dichloride, 1.9 g of copper(I) iodide, 100 mL of DMF, and 500 mL of triethylamine, and the mixture was stirred at 80°C for 8 hours under a nitrogen atmosphere to react. After completion of the reaction, the solvent was removed under reduced pressure, and the mixture was separated into water and ethyl acetate, and the organic layer was concentrated. The obtained crude product was recrystallized from ethanol to obtain 16.8 g of dicarboxylic acid ester compound (7) represented by the following formula: [ka]

[0042] Example 5 43.9 g of compound (2) obtained in Example 1, 13.3 g of allyl bromide, 11.1 g of triethylamine, and 500 mL of tetrahydrofuran were added, heated to 70°C, and stirred for 1 hour. After completion of the reaction, the solvent was distilled off under reduced pressure, and the crude product was separated into water and diethyl ether. This separation operation was performed twice in total. The organic layer was concentrated to obtain 45.5 g of compound (8).

[0043] A flask was charged with 23.9 g of compound (8), 8.41 g of propiolic acid, 3.51 g of bis(triphenylphosphine)palladium(II) dichloride, 1.90 g of copper(I) iodide, 100 mL of DMF, and 500 mL of triethylamine, and the mixture was stirred at 80°C for 8 hours under a nitrogen atmosphere. After the reaction was completed, the solvent was removed under reduced pressure, and the mixture was separated into water and ethyl acetate, and the organic layer was concentrated. The obtained crude product was recrystallized from ethanol to obtain 17.4 g of dicarboxylic acid compound (7) represented by the following formula: [ka] [ka]

Claims

【Request Item 1】 A compound represented by general formula (1) (wherein, A is a direct bond, R is a hydrogen atom or a hydrocarbon group having 5 or less carbon atoms, and R １ is a hydrogen atom, a methyl group, an ethyl group, an n-propyl group, an n-butyl group, an s-butyl group, a t-butyl group, an allyl group, a homoallyl group, a cinnamyl group, or a propargyl group. 【Chemistry 1】

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