Method for producing phthalonitrile compounds

Abstract

One embodiment of the present invention provides a method for producing a phthalonitrile-based compound, comprising: (a) preparing a mixture containing a phthalic acid-based compound and a nitrile-based compound; and (b) reacting the mixture, wherein the step (b) is performed under a supercritical condition of the nitrile-based compound.

Description

[Technical Field]

[0001] The present specification relates to a method for producing a phthalonitrile compound, and more particularly to a method for producing a phthalonitrile compound directly from a phthalic acid compound. [Background technology]

[0002] Phthalonitrile compounds are important compounds used as intermediates in the production of fiber-forming linear polymers. They are also used as organic synthesis intermediates for various fine chemical products such as amines, acid-amides, and complex nitrogen dyes. They are also high-value-added raw materials used in plasticizers, alkyd resin modifiers, and insecticides.

[0003] Conventionally, phthalonitrile-based compounds have been produced by contacting xylene compounds with ammonia and oxygen-containing gases in the presence of an oxidation catalyst and then dehydrating them. However, this method is ammoxidation, which uses ammonia gas, a hazardous chemical, and is carried out in the presence of a catalyst at high temperature and pressure, making the process complicated. Furthermore, high-boiling impurities must be purified and separated through distillation, making it difficult to remove by-products. Furthermore, in these conventional methods for producing phthalonitrile-based compounds, the product yield varies depending on the type of catalyst and the ratio of oxygen-containing gas used in the ammoxidation reaction. Furthermore, the conversion rate of the precursor xylene compound varies depending on the reaction temperature, making process control difficult.

[0004] Therefore, there is an increasing demand for a process for producing high purity phthalonitrile-based compounds in an economical and environmentally friendly manner. Summary of the Invention [Problem to be solved by the invention]

[0005] An object of the present invention is to provide a method for directly producing phthalonitrile-based compounds from phthalic acid-based compounds.

[0006] Another object of the present invention is to provide an environmentally friendly method for producing phthalonitrile compounds. [Means for solving the problem]

[0007] According to one aspect, there is provided a method for producing a phthalonitrile-based compound, comprising: (a) preparing a mixture containing a phthalic acid-based compound and a nitrile-based compound; and (b) reacting the mixture, wherein step (b) is performed under supercritical conditions of the nitrile-based compound.

[0008] In one embodiment, the phthalic acid compound may be isophthalic acid, terephthalic acid, or a mixture thereof.

[0009] In one embodiment, the nitrile-based compound may be at least one selected from the group consisting of hydrogen cyanide, acetonitrile, acrylonitrile, butyronitrile, isobutyronitrile, pivalonitrile, succinonitrile, fumaronitrile, crotonitrile, and benzonitrile.

[0010] In one embodiment, the nitrile compound may be acetonitrile.

[0011] In one embodiment, the mixture in step (a) may be composed of a phthalic acid-based compound and a nitrile-based compound.

[0012] In one embodiment, in step (a), the content of the nitrile compound may be 1 to 500 parts by weight based on 1 part by weight of the phthalic acid compound.

[0013] In one embodiment, in step (a), the water content of the mixture may be less than 6,000 ppm.

[0014] In one embodiment, the step (b) may be carried out under conditions of 260 to 350°C and 40 to 200 bar.

[0015] In one embodiment, step (b) may be carried out for 1 to 500 minutes.

[0016] In one embodiment, after step (b), the method may further include a step (c) of separating the product of step (b).

[0017] In one embodiment, the residual compounds separated in step (c) can be reused in step (a). [Effects of the Invention]

[0018] According to one aspect, a highly pure phthalonitrile compound can be produced directly from a phthalic acid compound.

[0019] In another aspect, an environmentally friendly phthalonitrile compound can be produced.

[0020] The effects of the matters described in this specification are not limited to the effects described above, but should be understood to include all effects that can be inferred from the configurations described in the detailed description or claims of this specification. BEST MODE FOR CARRYING OUT THE INVENTION

[0021] Hereinafter, one aspect of the present specification will be described with reference to an embodiment. However, the subject matter described in the present specification may be embodied in various different forms and is not limited to the embodiment described herein. Furthermore, in order to clearly describe each content for implementing the present specification, parts that are not relevant to the description or that are well known in the art will be omitted.

[0022] Throughout this specification, the term "connected" to another part includes not only "directly connected" but also "indirectly connected" through an intervening member. Furthermore, unless otherwise specified, the term "comprises" a certain component does not exclude other components but means that the component may further comprise other components.

[0023] When a range of numerical values ​​is described herein, unless a specific range is otherwise stated, the values ​​have the precision of significant figures provided by standard chemistry rules for significant figures. For example, the number 10 includes a range of 5.0 to 14.9, and the number 10.0 includes a range of 9.50 to 10.49. Also, when multiple examples of numerical values ​​are described herein, such examples can include intermediate values ​​unless explicitly stated to exclude those intermediate values. For example, "x1, x2, x3, or x4" can include the ranges "x1 to x2," "x1 to x3," "x1 to x4," "x2 to x3," "x2 to x4," and "x3 to x4."

[0024] As used herein, the term "supercritical condition" refers to a state in which the conditions above the critical point, which is the end point of the phase equilibrium curve, are satisfied. For example, when the critical temperature of compound A is T c and the critical pressure is P c Then, the supercritical condition of compound A occurs when the temperature is T c and the pressure is P c This means that the condition is equal to or greater than the specified value.

[0025] An embodiment of the present specification will be described in detail below.

[0026] Method for producing phthalonitrile compounds According to one aspect, a method for producing a phthalonitrile-based compound includes: (a) preparing a mixture containing a phthalic acid-based compound and a nitrile-based compound; and (b) reacting the mixture, wherein step (b) may be performed under supercritical conditions of the nitrile-based compound.

[0027] The phthalic acid compound may be a compound having an aromatic ring and two or more carboxyl groups. In one embodiment, the phthalic acid compound may be isophthalic acid, terephthalic acid, or a mixture thereof.

[0028] The nitrile-based compound may be at least one selected from the group consisting of hydrogen cyanide, acetonitrile, acrylonitrile, butyronitrile, isobutyronitrile, pivalonitrile, succinonitrile, fumaronitrile, crotonitrile, and benzonitrile, but is not limited thereto. For example, when the nitrile-based compound is hydrogen cyanide, step (b) may be performed under conditions of 183.5°C or higher and 50 bar or higher. When the nitrile-based compound is acetonitrile, step (b) may be performed under conditions of 272°C or higher and 48.7 bar or higher. When the nitrile-based compound is acrylonitrile, step (b) may be performed under conditions of 267°C or higher and 46 bar or higher. When the nitrile-based compound is butyronitrile, step (b) may be performed under conditions of 309°C or higher and 37.8 bar or higher. When the nitrile-based compound is isobutyronitrile, step (b) may be performed under conditions of 336°C or higher and 40 bar or higher. When the nitrile-based compound is pivalonitrile, step (b) may be carried out under conditions of 343°C or higher and 34.4 bar or higher. Furthermore, the conditions for step (b) may vary depending on the type of nitrile-based compound. Therefore, the above conditions are merely exemplary and do not limit the scope of the present specification. The nitrile-based compound may be both a solvent and a reactant.

[0029] In step (b), the mixture may be reacted without the addition of additional additives such as ammonia, high-concentration oxygen, or a catalyst. Because the reaction in step (b) can be performed without additional additives, the mixture in step (a) may be composed of a phthalic acid-based compound and a nitrile-based compound, but is not limited thereto. For example, the mixture may be composed of a phthalic acid-based compound in a solid phase dissolved in a nitrile-based compound solvent, but is not limited thereto.

[0030] In step (a), the content of the nitrile compound may be 1 to 500 parts by weight based on 1 part by weight of the phthalic acid compound. For example, the content of the nitrile compound may be 1 part by weight, 5 parts by weight, 10 parts by weight, 15 parts by weight, 20 parts by weight, 25 parts by weight, 30 parts by weight, 35 parts by weight, 40 parts by weight, 45 parts by weight, 50 parts by weight, 55 parts by weight, 60 parts by weight, 65 parts by weight, 70 parts by weight, 75 parts by weight, 80 parts by weight, 85 parts by weight, 90 parts by weight, 95 parts by weight, 100 parts by weight, 105 parts by weight, 110 parts by weight, 115 parts by weight, 12 parts by weight, 130 parts by weight, 140 parts by weight, 150 parts by weight, 160 parts by weight, 170 parts by weight, 180 parts by weight, 190 parts by weight, 200 parts by weight, 210 parts by weight, 220 parts by weight, 230 parts by weight, 240 parts by weight, 250 parts by weight, 260 parts by weight, 270 parts by weight, 280 parts by weight, 290 parts by weight, 300 parts by weight, 310 parts by weight, 320 parts by weight, 330 parts by weight, 340 parts by weight, 350 parts by weight, 360 parts by weight, 370 parts by weight, 380 parts by weight, 390 parts by weight, 400 parts by weight, 410 parts by weight, 420 parts by weight, 430 parts by weight, 440 parts by weight, 450 parts by weight, 460 parts by weight, 470 parts by weight, 0 parts by weight, 125 parts by weight, 130 parts by weight, 135 parts by weight, 140 parts by weight, 145 parts by weight, 150 parts by weight, 155 parts by weight, 160 parts by weight, 165 parts by weight, 170 parts by weight, 175 parts by weight, 180 parts by weight, 185 parts by weight parts, 190 parts by weight, 195 parts by weight, 200 parts by weight, 205 parts by weight, 210 parts by weight, 215 parts by weight, 220 parts by weight, 225 parts by weight, 230 parts by weight, 235 parts by weight, 240 parts by weight, 245 parts by weight, 250 parts by weight, 2 55 parts by weight, 260 parts by weight, 265 parts by weight, 270 parts by weight, 275 parts by weight, 280 parts by weight, 285 parts by weight, 290 parts by weight, 295 parts by weight, 300 parts by weight, 305 parts by weight, 310 parts by weight, 315 parts by weight, 320 parts by weight Parts by weight, 325 parts by weight, 330 parts by weight, 335 parts by weight, 340 parts by weight, 345 parts by weight, 350 parts by weight, 355 parts by weight, 360 parts by weight, 365 parts by weight, 370 parts by weight, 375 parts by weight, 380 parts by weight, 385 parts by weight , 390 parts by weight, 395 parts by weight, 400 parts by weight, 405 parts by weight, 410 parts by weight, 415 parts by weight, 420 parts by weight, 425 parts by weight, 430 parts by weight, 435 parts by weight, 440 parts by weight, 445 parts by weight, 450 parts by weight, 455 parts by weight, 460 parts by weight, 465 parts by weight, 470 parts by weight, 475 parts by weight, 480 parts by weight, 485 parts by weight, 490 parts by weight, 495 parts by weight, or 500 parts by weight, and may include intermediate ranges thereof. As the content of the nitrile-based compound increases relative to the content of the phthalic acid-based compound, the purity of the product may increase, but an excessively high content of the nitrile-based compound may be economically disadvantageous.

[0031] In step (a), the mixture may have a water content of less than 6,000 ppm. For example, the water content of the mixture may be less than 6,000 ppm, less than 5,000 ppm, less than 4,000 ppm, less than 3,000 ppm, less than 2,000 ppm, less than 1,000 ppm, less than 750 ppm, less than 500 ppm, or less than 250 ppm. The lower the water content of the mixture, the higher the purity of the product.

[0032] The reaction in step (b) may be di-nitrilation through a direct substitution reaction between a carboxyl group and a nitrile group, and one example thereof may be expressed as the following reaction scheme:

[0033] [ka]

[0034] In the above reaction formula, R is an aromatic ring such as phenylene, and R' may be an alkyl group having 1 to 20 carbon atoms, such as a methyl group, an ethyl group, an isopropyl group, or a t-butyl group.

[0035] The reaction can be carried out under the temperature and pressure conditions of step (b) above the critical point of the nitrile-based compound. Step (b) can be carried out under conditions of 260 to 350°C and 40 to 200 bar. For example, step (b) can be carried out at a reaction temperature of 260°C, 265°C, 270°C, 275°C, 280°C, 285°C, 290°C, 295°C, 300°C, 305°C, 310°C, 315°C, 320°C, 325°C, 330°C, 335°C, 340°C, 345°C, or 350°C. For example, step (b) may be carried out at a reaction pressure of 40 bar, 45 bar, 50 bar, 55 bar, 60 bar, 65 bar, 70 bar, 75 bar, 80 bar, 85 bar, 90 bar, 95 bar, 100 bar, 105 bar, 110 bar, 115 bar, 120 bar, 125 bar, 130 bar, 135 bar, 140 bar, 145 bar, 150 bar, 155 bar, 160 bar, 165 bar, 170 bar, 175 bar, 180 bar, 185 bar, 190 bar, 195 bar, or 200 bar. If the reaction temperature in step (b) is too low, the purity of the product may decrease or the reaction may not occur. If the reaction temperature is too high, the production of by-products may increase, resulting in a decrease in purity. If the reaction pressure in step (b) is too low, the reaction may not proceed, whereas if the reaction pressure is too high, safety may be compromised.

[0036] The step (b) may be carried out for 1 to 500 minutes. For example, the step (b) may be carried out for 1 minute, 5 minutes, 10 minutes, 15 minutes, 20 minutes, 25 minutes, 30 minutes, 35 minutes, 40 minutes, 45 minutes, 50 minutes, 55 minutes, 60 minutes, 65 minutes, 70 minutes, 75 minutes, 80 minutes, 85 minutes, 90 minutes, 95 minutes, 100 minutes, 105 minutes, 110 minutes, 115 minutes, 120 minutes, 125 minutes, 130 minutes, 135 minutes, or the like. , 140 minutes, 145 minutes, 150 minutes, 155 minutes, 160 minutes, 165 minutes, 170 minutes, 175 minutes, 180 minutes, 185 minutes, 190 minutes, 195 minutes, 200 minutes, 205 minutes, 210 minutes, 215 minutes, 220 minutes, 225 minutes, 230 minutes, 235 minutes, 240 minutes, 245 minutes, 250 minutes, 255 minutes, 260 minutes, 265 minutes , 270 minutes, 275 minutes, 280 minutes, 285 minutes, 290 minutes, 295 minutes, 300 minutes, 305 minutes, 310 minutes, 315 minutes, 320 minutes, 325 minutes, 330 minutes, 335 minutes, 340 minutes, 345 minutes, 350 minutes, 355 minutes, 360 minutes, 365 minutes, 370 minutes, 375 minutes, 380 minutes, 385 minutes, 390 minutes, 395 minutes, 400 minutes, 405 minutes, 410 minutes, 415 minutes, 420 minutes, 425 minutes, 430 minutes, 435 minutes, 440 minutes, 445 minutes, 450 minutes, 455 minutes, 460 minutes, 465 minutes, 470 minutes, 475 minutes, 480 minutes, 485 minutes, 490 minutes, 495 minutes, or 500 minutes, and intermediate ranges therebetween may be included. As the reaction time of step (b) increases, the purity of the product can be increased, but if the reaction time is too long, productivity can decrease.

[0037] After step (b), the method may further include step (c) of separating the product of step (b). The separation in step (c) may be performed by separating the resulting phthalonitrile-based compound from the remaining compound, and may be performed by various known methods, such as distillation. The remaining compound may include, but is not limited to, at least one selected from the group consisting of unreacted phthalic acid-based compounds, unreacted nitrile-based compounds, and phthalonitrile-based compounds in which only a portion of the carboxyl groups of a phthalic acid-based compound have reacted.

[0038] The residual compound separated in step (c) can be reused in step (a). Since the method for producing a phthalonitrile-based compound according to an embodiment can be carried out without using a separate additive such as a catalyst, the residual compound can be reused without separate purification.

[0039] In one aspect of the method for producing a phthalonitrile compound, the purity of the product may be 60% or more, 65% or more, 70% or more, 75% or more, 80% or more, or 85% or more.

[0040] The examples of the present specification will be described in more detail below. However, the following experimental results are only representative of the examples, and should not be construed as narrowing or limiting the scope and content of the present specification. The respective effects of the various examples of the present specification that are not explicitly presented below will be specifically described in the relevant sections.

[0041] Example 1 A reaction system was formed by adding 5 parts by weight of isophthalic acid (IPA) and 100 parts by weight of acetonitrile (ACN) to a 1,000 mL autoclave equipped with a stirrer. The reactor was purged with nitrogen three times at a pressure of 2-3 bar. The reactor was stirred at 400 rpm under atmospheric pressure and the internal temperature was raised to 280-300°C. The reaction was continued for 4 hours while maintaining the reaction temperature. The reaction pressure was 70-100 bar. After the reaction was completed, the reaction system was cooled to room temperature. The reaction system was then distilled under reduced pressure to separate acetonitrile and isophthalonitrile (IPN). The acetonitrile was reused, and the purity of the isophthalonitrile was confirmed by gas chromatography (GC).

[0042] Example 2 A reaction system was formed by adding 5 parts by weight of isophthalic acid and 100 parts by weight of acetonitrile to a 1,000 mL reactor equipped with a stirrer. The interior of the reactor was purged with nitrogen three times at a pressure of 2 to 3 bar. The reactor was stirred at 400 rpm under atmospheric pressure, and the internal temperature was raised to 290°C. The reaction was carried out for 1 to 6 hours while maintaining the reaction temperature. The reaction pressure was 90 to 95 bar. After the reaction was completed, the reaction system was cooled to room temperature. The reaction system was then distilled under reduced pressure to separate acetonitrile and isophthalonitrile. The acetonitrile was reused, and the purity of the isophthalonitrile was confirmed by gas chromatography.

[0043] Example 3 A reaction system was formed by adding 5 parts by weight of isophthalic acid and 50-150 parts by weight of acetonitrile to a 1,000 mL reactor equipped with a stirrer. The reactor was purged with nitrogen three times at a pressure of 2-3 bar. The reactor was stirred at 400 rpm under atmospheric pressure, and the internal temperature was raised to 290°C. The reaction was carried out for 4 hours while maintaining the reaction temperature. The reaction pressure was 90-95 bar. After the reaction was completed, the reaction system was cooled to room temperature. The reaction system was then distilled under reduced pressure to separate acetonitrile and isophthalonitrile. The acetonitrile was reused, and the purity of the isophthalonitrile was confirmed by gas chromatography.

[0044] Example 4 A reaction system was formed by adding 5 parts by weight of isophthalic acid and 100 parts by weight of acetonitrile to a 1,000 mL reactor equipped with a stirrer. The interior of the reactor was purged with nitrogen three times at a pressure of 2 to 3 bar. The water content of the reaction system was adjusted to 260 to 6,000 ppm. The reactor was stirred at 400 rpm at atmospheric pressure while the internal temperature was raised to 280°C. The reaction was carried out for 4 hours while maintaining the reaction temperature. The reaction pressure was 70 to 75 bar. After the reaction was completed, the reaction system was cooled to room temperature. The reaction system was then distilled under reduced pressure to separate acetonitrile and isophthalonitrile. The acetonitrile was reused, and the purity of the isophthalonitrile was confirmed by gas chromatography.

[0045] Example 5 A reaction system was formed by adding 5 parts by weight of terephthalic acid (TPA) and 100 parts by weight of acetonitrile to a 1,000 mL reactor equipped with a stirrer. The reactor was purged with nitrogen three times at a pressure of 2-3 bar. The reactor was stirred at 400 rpm under atmospheric pressure, and the internal temperature was raised to 280-290°C. The reaction was continued for 4 hours while maintaining the reaction temperature. The reaction pressure was 75-95 bar. After the reaction was completed, the reaction system was cooled to room temperature. The reaction system was then distilled under reduced pressure to separate acetonitrile and terephthalonitrile (TPN). The acetonitrile was reused, and the purity of the product was confirmed by gas chromatography.

[0046] The reaction conditions and product purities of Examples 1 to 5 are summarized in Table 1 below.

[0047] [Table 1]

[0048] Referring to Example 1, as the reaction temperature increases, the purity of the product isophthalonitrile increases, but if the reaction temperature is too high, the amount of by-products increases and the purity decreases.

[0049] Referring to Example 2, the purity of the product isophthalonitrile increased as the reaction time increased.

[0050] Furthermore, referring to Example 3, it was confirmed that the purity of the product isophthalonitrile tends to increase as the amount of isophthalic acid decreases relative to acetonitrile.

[0051] Referring to Example 4, the higher the water content in the reaction system, the more by-products were produced, and the purity of the product, isophthalonitrile, decreased.

[0052] Referring to Example 5, it can be confirmed that terephthalonitrile can be produced using a similar reaction mechanism by using terephthalic acid instead of isophthalic acid. In addition, the purity of the product isophthalonitrile increased as the reaction temperature increased.

[0053] Referring to Examples 1 to 5, unlike conventional manufacturing processes using ammonia reaction that use harmful compounds such as ammonia and acid catalysts, one embodiment of the present specification can manufacture phthalonitrile-based compounds from solid phthalic acid compounds in high yields without adding any additional catalysts or additives.

[0054] Specifically, in Examples 1 to 5, isophthalic acid or terephthalic acid, which are phthalic acid compounds, were used as reactants, and acetonitrile, which is an organic nitrile, was used as both a solvent and a reactant. These mixtures were directly heated without adding any additional catalyst or additives to create a supercritical state (T c :275℃ or higher, P c The resulting pressure was 48 bar or higher, which induced an exchange reaction between the acid and the nitrile to directly produce phthalonitrile compounds.

[0055] The above description of the present specification is for illustrative purposes only, and a person skilled in the art to which one aspect of the present specification pertains will understand that the present specification may be easily modified into other specific forms without changing the technical ideas or essential features described herein. Therefore, the above-described embodiments should be understood to be illustrative in all respects and not limiting. For example, each component described as a single component may be implemented in a distributed form, and similarly, each component described as a distributed component may be implemented in a combined form.

[0056] The scope of this specification is defined by the claims set forth below, and all modifications and variations derived from the meaning and scope of the claims and their equivalent concepts should be construed as being included within the scope of the present invention.

Claims

1. (a) preparing a mixture comprising a phthalic acid compound and a nitrile compound; and (b) reacting the mixture; The step (b) is carried out under supercritical conditions of the nitrile compound, the phthalic acid compound is isophthalic acid, terephthalic acid, or a mixture thereof; The nitrile compound is at least one selected from the group consisting of hydrogen cyanide, acetonitrile, acrylonitrile, butyronitrile, isobutyronitrile, pivalonitrile, succinonitrile, fumaronitrile, crotonitrile, and benzonitrile; In step (b), the purity of the product in which two carboxyl groups in the phthalic acid compound are substituted with nitrile groups is 60% or more; However, the method for producing a phthalonitrile-based compound includes: a first reaction section filled with a mixture containing a phthalic acid-based compound and a nitrile-based compound; a second reaction section connected to the first reaction section; and a discharge section connected to the second reaction section, wherein a fluid flows in the second reaction section from the first reaction section to the discharge section, and the length of the second reaction section in the fluid flow direction is 10 times or more the square root of the average cross-sectional area perpendicular to the fluid flow direction, and the method is not carried out using a system for producing a phthalonitrile-based compound using a continuous process.

2. 2. The method for producing a phthalonitrile compound according to claim 1, wherein the nitrile compound is acetonitrile.

3. 3. The method for preparing a phthalonitrile-based compound according to claim 1 or 2, wherein the mixture in step (a) comprises a phthalic acid-based compound and a nitrile-based compound.

4. 4. The method for producing a phthalonitrile-based compound according to claim 1, wherein in step (a), the amount of the nitrile-based compound is 1 to 500 parts by weight based on 1 part by weight of the phthalic acid-based compound.

5. 5. The method for producing a phthalonitrile compound according to claim 1, wherein the water content of the mixture in step (a) is less than 6,000 ppm.

6. 6. The method for preparing a phthalonitrile compound according to claim 1, wherein step (b) is carried out under conditions of 260 to 350° C. and 40 to 200 bar.

7. 7. The method for preparing a phthalonitrile compound according to claim 1, wherein step (b) is carried out for 1 to 500 minutes.

8. The method for producing a phthalonitrile compound according to any one of claims 1 to 7, further comprising, after step (b), (c) separating the product of step (b).

9. 9. The method for producing a phthalonitrile compound according to claim 8, wherein the remaining compound separated in step (c) is reused in step (a).

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