Method for releasing carbon dioxide

Abstract

To provide a novel method for releasing carbon dioxide using a carbamic acid derivative which is a reaction product of an amine compound and carbon dioxide and does not use a reaction solution including a reaction product of the amine compound and carbon dioxide as a carbamic acid derivative-containing solution.SOLUTION: A method for releasing carbon dioxide comprises the steps for: preparing a dispersion by dispersing a reaction product of one or more kinds selected from the group consisting of isophoronediamine, 4,4'-methylenebis (cyclohexylamine) and 4,4'-methylenebis (2-methylcyclohexylamine) with carbon dioxide in one kind of solvent selected from the group consisting of methanol, ethanol and N, N-dimethylformamide or in two or more mixed solvents; and releasing the carbon dioxide from the reaction product by heat-treating the dispersion or supplying an inert gas into the dispersion without heating the dispersion.SELECTED DRAWING: None

Description

[Technical field]

[0001] The present invention relates to a method for releasing carbon dioxide. [Background technology]

[0002] Carbon dioxide gas is a greenhouse gas, and its increasing concentration in the atmosphere causes global warming. On Earth, the progress of civilization has led to mass consumption of fossil fuels, and carbon dioxide emissions have continued to increase. In response to this, plants absorb carbon dioxide through photosynthesis and release oxygen. However, deforestation has progressed on a global scale, resulting in the loss of large amounts of plants, and the consumption of carbon dioxide has continued to decrease. As a result, the concentration of carbon dioxide in the atmosphere has been increasing, and various adverse effects thought to be caused by global warming have been observed on a global scale. Against this background, various technologies are being considered for absorbing and fixing carbon dioxide in the atmosphere.

[0003] For example, a specific range of amine compounds having an amino group is dissolved in a solvent, and the resulting amine compound solution is made to absorb carbon dioxide gas, and the amine compound reacts with carbon dioxide at its amino group to convert the amino group (-NH 2 A technology has been disclosed in which a carbamic acid derivative in which a carboxyamino group (-NH-C(=O)-OH) is formed from a carboxylic acid group (-NH-C(=O)-OH) is absorbed and fixed in carbon dioxide (see Patent Document 1). The carbamic acid derivative-containing liquid in which a carbamic acid derivative is formed in the amine compound solution can be either a dispersion in which the carbamic acid derivative is precipitated or a solution in which the carbamic acid derivative is not precipitated, and which one is obtained depends on the combination of the carbamic acid derivative and the solvent.

[0004] Patent Document 1 further discloses that the carbamic acid derivative-containing liquid can be heated to release carbon dioxide gas from the carbamic acid derivative and regenerate the amine compound, and that the regenerated amine compound can be made into an amine compound solution again to absorb and release carbon dioxide gas. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] International Publication No. 2022 / 085789 Summary of the Invention [Problem to be solved by the invention]

[0006] The carbon dioxide releasing method disclosed in Patent Document 1 is advantageous in that the process can be simplified because the absorption and release of carbon dioxide can be continuously performed by directly heating the carbamic acid derivative-containing liquid. However, in this carbon dioxide releasing method, the object of the heat treatment is the carbamic acid derivative-containing liquid, that is, the reaction liquid containing the reaction product of the amine compound and carbon dioxide, and the composition of the carbon dioxide releasing agent is limited, and there has been insufficient consideration for more efficiently releasing carbon dioxide. If the composition of the carbon dioxide releasing agent is not limited in this way, for example, the release of carbon dioxide may be further improved in efficiency by lowering the heat treatment temperature. Therefore, the development of a new carbon dioxide releasing method is desired.

[0007] The present invention is a method for releasing carbon dioxide using a carbamic acid derivative, which is a reaction product of an amine compound and carbon dioxide, and an object of the present invention is to provide a novel method for releasing carbon dioxide, which does not use a reaction liquid containing a reaction product of an amine compound and carbon dioxide as the carbamic acid derivative-containing liquid. [Means for solving the problem]

[0008] The present invention employs the following configuration. [1] A method for releasing carbon dioxide, comprising the steps of: preparing a dispersion by dispersing a reaction product of carbon dioxide and one or more members selected from the group consisting of isophoronediamine, 4,4'-methylenebis(cyclohexylamine) and 4,4'-methylenebis(2-methylcyclohexylamine) in one solvent or a mixed solvent of two or more members selected from the group consisting of methanol, ethanol and N,N-dimethylformamide; and releasing the carbon dioxide from the reaction product by heating the dispersion, or by supplying an inert gas or air into the dispersion without heating the dispersion. [2] The method for releasing carbon dioxide according to [1], wherein in the step of releasing carbon dioxide, the dispersion is heat-treated while supplying nitrogen gas into the dispersion. [3] The method for releasing carbon dioxide described in [1] or [2], wherein in the step of releasing carbon dioxide, the dispersion is heat-treated while applying ultrasonic vibrations to the dispersion or while stirring the dispersion, or the dispersion is heat-treated and then ultrasonic vibrations are applied to the dispersion or the dispersion is stirred. [4] The method for releasing carbon dioxide according to any one of [1] to [3], wherein in the step of releasing carbon dioxide, the dispersion is heat-treated without supplying the inert gas or air.

[0009] [5] The method for releasing carbon dioxide according to any one of claims [1] to [4], wherein the heating temperature when the dispersion is heat-treated is 60°C or lower. [6] The method for releasing carbon dioxide according to any one of [1] to [3] and [5], wherein the inert gas or air is supplied to the dispersion liquid at a flow rate of 20 to 110 mL / min. Effect of the Invention

[0010] According to the present invention, there is provided a novel method for releasing carbon dioxide using a carbamic acid derivative, which is a reaction product of an amine compound and carbon dioxide, and which does not use a reaction liquid containing a reaction product of an amine compound and carbon dioxide as the carbamic acid derivative-containing liquid. [Brief description of the drawings]

[0011] [Figure 1] 1 is a spectrum data showing the analysis results of the carbamic acid derivative obtained in Production Example 1 by 13C-NMR. [Diagram 2] 1 is a graph showing the measurement results of the concentration of carbon dioxide in the exhaust gas when carbon dioxide is released in Examples 1 to 3 and Reference Examples 1 to 5. [Diagram 3] 1 is a spectrum data showing the analysis results of the isophoronediamine regenerated in Example 1 by 13C-NMR. [Figure 4] 1 is a graph showing the measurement results of the concentration of carbon dioxide in the exhaust gas when carbon dioxide is released in Examples 4 to 8. [Diagram 5] 1 is a graph showing the measurement results of the concentration of carbon dioxide in the exhaust gas when carbon dioxide is released in Examples 9 to 14. [Figure 6] 1 is a graph showing the measurement results of the concentration of carbon dioxide in the exhaust gas when carbon dioxide is released in Examples 15 to 17. [Figure 7] 1 is a graph showing the measurement results of the concentration of carbon dioxide in the exhaust gas when carbon dioxide is released in Examples 19 to 21. [Figure 8] 1 is a graph showing the measurement results of the concentration of carbon dioxide in the exhaust gas when carbon dioxide is released in Examples 22 to 26. [Figure 9] 1 is a graph showing the measurement results of the concentration of carbon dioxide in the exhaust gas when carbon dioxide is released in Examples 27 and 29. [Figure 10]FIG. 1 shows spectral data showing the results of FT-IR analysis of the carbamic acid derivative obtained in Production Example 2, where (a) is spectral data in the wavelength range of 4000 nm or less, and (b) is expanded spectral data in the wavelength range of 1500 to 1700 nm. [Figure 11] 13 is a graph showing the measurement results of the concentration of carbon dioxide in the exhaust gas when carbon dioxide is released in Examples 33 and 34. [Figure 12] FIG. 1 shows spectral data showing the results of FT-IR analysis of the carbamic acid derivative obtained in Production Example 3, where (a) is spectral data in the wavelength range of 4000 nm or less, and (b) is expanded spectral data in the wavelength range of 1500 to 1700 nm. [Figure 13] 13 is a graph showing the measurement results of the concentration of carbon dioxide in the exhaust gas when carbon dioxide is released in Examples 35 and 36. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0012] ◇How to release carbon dioxide A method for releasing carbon dioxide according to one embodiment of the present invention comprises reacting a compound containing one or more selected from the group consisting of isophoronediamine (also known as 3-(aminomethyl)-3,5,5-trimethylcyclohexane-1-amine, sometimes referred to as "IPDA" in this specification), 4,4'-methylenebis(cyclohexylamine) (sometimes referred to as "MBCHA" in this specification) and 4,4'-methylenebis(2-methylcyclohexylamine) (sometimes referred to as "MBMCHA" in this specification) with carbon dioxide, to obtain a reaction product (sometimes referred to as "MBMCHA" in this specification). The method includes a step of preparing a dispersion by dispersing a reactant (sometimes referred to as a "carbamic acid derivative" in this specification) in one solvent or a mixed solvent of two or more solvents selected from the group consisting of methanol, ethanol, and N,N-dimethylformamide (DMF) (sometimes referred to as a "dispersion preparation step" in this specification), and a step of releasing the carbon dioxide from the reactant by heating the dispersion or supplying an inert gas or air into the dispersion without heating the dispersion (sometimes referred to as a "carbon dioxide releasing step" in this specification).

[0013] The method for releasing carbon dioxide in this embodiment differs from conventional methods for releasing carbon dioxide in that a specific range of carbamic acid derivatives that are solid at room temperature and obtained using a specific range of amine compounds having an amino group in the molecule are used, and a specific range of solvents (dispersion media) for dispersing the carbamic acid derivatives are used. According to the carbon dioxide releasing method of the present embodiment, by using the dispersion obtained by the dispersion preparation step as the carbamic acid derivative-containing liquid, which is a carbon dioxide releasing agent, instead of using a reaction liquid containing a reactant of an amine compound and carbon dioxide, it is possible to release carbon dioxide under conditions different from those of the past, and it is also possible to release carbon dioxide more efficiently than before. For example, when a dispersion in which a carbamic acid derivative is dispersed in a solvent is heat-treated, it may be possible to sufficiently release carbon dioxide by lowering the heat treatment temperature than before, or even without performing heat treatment.

[0014] The method for releasing carbon dioxide in this embodiment can be classified into two methods depending on whether or not the dispersion liquid is heat-treated. That is, the method for releasing carbon dioxide in the first embodiment of the present invention includes a step of preparing a dispersion by dispersing a reaction product (carbamic acid derivative) of carbon dioxide and one or more selected from the group consisting of isophoronediamine (IPDA), 4,4'-methylenebis(cyclohexylamine) (MBCHA) and 4,4'-methylenebis(2-methylcyclohexylamine) (MBMCHA) in one solvent or a mixed solvent of two or more selected from the group consisting of methanol, ethanol and N,N-dimethylformamide (dispersion preparation step), and a step of releasing the carbon dioxide from the reaction product by heat-treating the dispersion (carbon dioxide releasing step). The carbon dioxide releasing method of the second embodiment of the present invention includes a step of preparing a dispersion by dispersing a reaction product (carbamic acid derivative) of carbon dioxide and one or more selected from the group consisting of isophoronediamine (IPDA), 4,4'-methylenebis(cyclohexylamine) (MBCHA) and 4,4'-methylenebis(2-methylcyclohexylamine) (MBMCHA) in one solvent or a mixed solvent of two or more selected from the group consisting of methanol, ethanol and N,N-dimethylformamide (dispersion preparation step), and a step of releasing the carbon dioxide from the reaction product by supplying an inert gas or air into the dispersion without heating the dispersion (carbon dioxide releasing step).

[0015] First, the carbon dioxide releasing method of the first embodiment will be described below.

[0016] First embodiment <<Dispersion preparation process>> <Carbamic acid derivatives> The carbamic acid derivatives used in the dispersion preparation step of the first embodiment include a reaction product of isophoronediamine (IPDA) and carbon dioxide, a reaction product of 4,4'-methylenebis(cyclohexylamine) (MBCHA) and carbon dioxide, and a reaction product of 4,4'-methylenebis(2-methylcyclohexylamine) (MBMCHA) and carbon dioxide. The structural formulae of IPDA, MBCHA, and MBMCHA are shown below.

[0017] [ka]

[0018] Among the carbamic acid derivatives, the reaction product of IPDA with carbon dioxide is an amino group (-NH 2 ) is a carboxyamino group (-NH-COOH); 2 compounds in which only the amino group bonded to the cyclohexyl group via a methylene group is a carboxyamino group; and compounds in which both the amino group directly bonded to the cyclohexyl group in IPDA and the amino group bonded to the cyclohexyl group via a methylene group are carboxyamino groups.

[0019] Among these, the reaction product of IPDA and carbon dioxide is preferably a compound represented by the following formula (1), in which only the amino group directly bonded to the cyclohexyl group in IPDA is a carboxyamino group. Such a reaction product can be prepared more easily and can release carbon dioxide more easily.

[0020] [ka]

[0021] Among the carbamic acid derivatives, examples of the reaction products between MBCHA and carbon dioxide include a compound in which only one of the two amino groups directly bonded to the cyclohexyl group in MBCHA has become a carboxyamino group; and a compound in which both of the amino groups directly bonded to the cyclohexyl group in MBCHA have become carboxyamino groups.

[0022] Among these, the reaction product of MBCHA and carbon dioxide is preferably a compound in which only one of the two amino groups directly bonded to the cyclohexyl group in MBCHA is a carboxyamino group, as shown in the following formula (2). Such a reaction product can be prepared more easily and can release carbon dioxide more easily.

[0023] [ka]

[0024] Among the above-mentioned carbamic acid derivatives, examples of the reaction product of MBMCHA with carbon dioxide include a compound in which only one of the two amino groups directly bonded to the cyclohexyl group in MBMCHA has become a carboxyamino group; and a compound in which both of the amino groups directly bonded to the cyclohexyl group in MBMCHA have become carboxyamino groups.

[0025] Among these, the reaction product of MBMCHA and carbon dioxide is preferably a compound in which only one of the two amino groups directly bonded to the cyclohexyl group in MBMCHA is a carboxyamino group, as represented by the following formula (3). Such a reaction product can be prepared more easily and can release carbon dioxide more easily.

[0026] [ka]

[0027] In the carbamic acid derivative used in the dispersion preparation step of the first embodiment (the carbamic acid derivative in the dispersion), the group represented by the formula "-NHCOOH" is - " and a group represented by the formula "-NH 2 + COO - " may be any one of the groups represented by the formula:

[0028] The carbamic acid derivatives used in the dispersion liquid preparation step of the first embodiment have a common feature in that they are derived from an amine compound having only one amino group directly bonded to one cyclohexyl group.

[0029] The carbamic acid derivative used in the dispersion preparation step of the first embodiment (the carbamic acid derivative in the dispersion) may be one type only, or two or more types. When two or more types are used, the combination and ratio thereof can be arbitrarily selected depending on the purpose.

[0030] The carbamic acid derivative can be produced, for example, by reacting a corresponding amine compound with carbon dioxide. More specifically, the carbamic acid derivative can be produced by supplying carbon dioxide gas to the amine compound itself, or by selecting a solvent suitable for this reaction, for example, a solvent capable of dissolving the amine compound, and supplying carbon dioxide gas to a solution of the amine compound prepared by the selection. Carbon dioxide gas may be supplied alone or as a mixed gas with other gases, and the concentration of the supplied carbon dioxide gas may be, for example, 0.00001 to 100% by volume. If the produced carbamic acid derivative precipitates in the reaction solution, it may be taken out by filtration, and if it dissolves in the reaction solution, it may be crystallized and then similarly taken out by filtration. For example, if the carbamic acid derivative is produced at a production rate of 100% without using a solvent, the product itself may be used as it is in the next step. After the reaction of the amine compound with carbon dioxide, the resulting reaction liquid may be subjected to post-treatment by a known method, if necessary. The isolated carbamic acid derivative may be purified by a known method, if necessary. The carbamic acid derivative can be produced, for example, by the method described in WO 2022 / 085789.

[0031] The structure of the carbamic acid derivative can be confirmed by known techniques such as nuclear magnetic resonance (NMR) spectroscopy, mass spectrometry (MS), infrared spectroscopy (IR), ultraviolet-visible spectroscopy (UV-VIS absorption spectrum), and elemental analysis.

[0032] <Solvent> In the dispersion liquid preparation step of the first embodiment, the carbamic acid derivative is dispersed in one solvent selected from the group consisting of methanol, ethanol, and N,N-dimethylformamide, or dispersed in a mixed solvent of two or more solvents selected from the group consisting of methanol, ethanol, and N,N-dimethylformamide. When two or more kinds of solvents (dispersion media) are used in the dispersion liquid preparation step, their combination and ratio can be selected arbitrarily depending on the purpose.

[0033] <Dispersion> In the dispersion liquid prepared in the first embodiment, the concentration of the carbamic acid derivative is preferably 0.01 to 5 mol / L, and may be, for example, any of 0.01 to 2 mol / L, 0.01 to 0.8 mol / L, and 0.01 to 0.3 mol / L, any of 0.08 to 5 mol / L, 0.3 to 5 mol / L, and 0.8 to 5 mol / L, or may be 0.08 to 2 mol / L. When the concentration is equal to or higher than the lower limit, the amount of carbon dioxide released is increased. When the concentration is equal to or lower than the upper limit, the time required for the release of carbon dioxide to be completed is shortened.

[0034] In the dispersion preparation step of the first embodiment, in addition to the carbamic acid derivative, other components not corresponding to the solvent may or may not be dispersed or dissolved within a range that does not impair the effects of the present invention. That is, the dispersion prepared in the dispersion preparation step may or may not contain the carbamic acid derivative, the solvent, and other components other than these (the carbamic acid derivative and the solvent).

[0035] The other components can be arbitrarily selected depending on the purpose and are not particularly limited. An example of the other component is a solvent other than the solvents (methanol, ethanol, and N,N-dimethylformamide).

[0036] The other components dispersed or dissolved in the dispersion preparation step of the first embodiment (in other words, contained in the dispersion prepared in the dispersion preparation step of the first embodiment, the same applies below) may be one type only, or two or more types, and if there are two or more types, their combination and ratio can be selected arbitrarily depending on the purpose.

[0037] In the dispersion in the first embodiment, the ratio of the content of the other components to the total content of the components other than the solvent ([content of other components in the dispersion (parts by mass)] / [total content of components other than the solvent in the dispersion (parts by mass)]×100) can be appropriately adjusted depending on the type of the other components, but is preferably 10% by mass or less, more preferably 5% by mass or less, even more preferably 3% by mass or less, and particularly preferably 1% by mass or less. In this specification, unless otherwise specified, the term "solvent" simply means methanol, ethanol, and N,N-dimethylformamide, and does not mean the other solvents. The other solvents correspond to "components other than solvents". When the ratio is equal to or less than the upper limit, the amount of carbon dioxide released is greater. On the other hand, the ratio is 0% by mass or more.

[0038] In other words, in the dispersion liquid of the first embodiment, the ratio of the content of the carbamic acid derivative to the total content of components other than the solvent ([content of carbamic acid derivative in dispersion liquid (parts by mass)] / [total content of components other than the solvent in dispersion liquid (parts by mass)] x 100) can be adjusted appropriately depending on the type of the other components, but is preferably 90% by mass or more, more preferably 95% by mass or more, even more preferably 97% by mass or more, and particularly preferably 99% by mass or more. When the ratio is equal to or greater than the lower limit, the amount of carbon dioxide released is greater. On the other hand, the proportion is 100% by mass or less.

[0039] In order to adjust the content ratio of the carbamic acid derivative or the other components in the dispersion in the first embodiment to fall within the above-mentioned numerical range, the blending amount of the carbamic acid derivative or the other components may be adjusted in the dispersion preparation step so that it falls within the above-mentioned numerical range. For example, in the dispersion liquid preparation step of the first embodiment, when the carbamic acid derivative is dispersed in the solvent, the ratio of the amount of the carbamic acid derivative to the total amount of components other than the solvent ([amount of the carbamic acid derivative in the dispersion liquid preparation step (parts by mass)] / [total amount of components other than the solvent in the dispersion liquid preparation step (parts by mass)]×100) can be appropriately adjusted depending on the type of the other components, but is preferably 90% by mass or more, more preferably 95% by mass or more, even more preferably 97% by mass or more, and particularly preferably 99% by mass or more.

[0040] <<Carbon dioxide release process>> <Heat treatment conditions> [Heating temperature] In the carbon dioxide releasing step following the dispersion preparation step of the first embodiment, the heating temperature during the heat treatment of the dispersion is preferably lower than the boiling point of the carbamic acid derivative and is preferably lower than the boiling point of the solvent. By setting the temperature during the heat treatment within such a range, it is possible to suppress the dissipation of the carbamic acid derivative or the solvent.

[0041] In the carbon dioxide releasing step of the first embodiment, the heating temperature when the dispersion is heat-treated is preferably 30° C. or higher while satisfying the above-mentioned conditions (lower than the boiling point of the carbamic acid derivative and lower than the boiling point of the solvent), and may be, for example, any one of 35° C. or higher and 45° C. or higher. When the heating temperature is equal to or higher than the lower limit, the amount of carbon dioxide released becomes larger, and the time required for the release of carbon dioxide to be completed becomes shorter.

[0042] In the carbon dioxide releasing step of the first embodiment, the heating temperature when the dispersion is heat-treated may be any one of 100° C. or less, 80° C. or less, and 70° C., while satisfying the above-mentioned conditions (less than the boiling point of the carbamic acid derivative and less than the boiling point of the solvent), but is preferably 60° C. or less, and may be, for example, any one of 55° C. or less and 45° C. or less. By having the heating temperature be equal to or less than the upper limit, the amount of by-products generated during the release of carbon dioxide is reduced.

[0043] In the carbon dioxide releasing step of the first embodiment, the heating temperature when the dispersion is heat-treated can be appropriately adjusted within a numerical range set by arbitrarily combining any of the lower limit values ​​described above and any of the upper limit values ​​described above. For example, the heating temperature may be any of 30 to 100°C, 30 to 80°C, and 30 to 70°C, but is preferably 30 to 60°C, any of 30 to 55°C and 30 to 45°C, any of 35 to 60°C and 45 to 60°C, or 35 to 55°C. However, these are just examples of the heating temperature.

[0044] [Inert gas, air] In the carbon dioxide releasing step of the first embodiment, it is preferable to heat-treat the dispersion liquid while supplying an inert gas or air into the dispersion liquid, which increases the amount of carbon dioxide released and shortens the time required to complete the release of carbon dioxide. When the inert gas or air is supplied to the dispersion liquid, for example, it is preferable to flow the inert gas or air into the dispersion liquid and bubble it.

[0045] Examples of the inert gas include nitrogen gas, helium gas, and argon gas. Among these, nitrogen gas is particularly suitable because it is inexpensive. That is, in the carbon dioxide releasing step of the first embodiment, it is preferable to heat-treat the dispersion while supplying nitrogen gas into the dispersion.

[0046] In the carbon dioxide releasing step of the first embodiment, when an inert gas or air is supplied into the dispersion, the flow rate of the inert gas or air is preferably 20 to 110 L / min per 1 mol of the amount of the carbamic acid derivative in the dispersion, and may be, for example, any of 20 to 80 L / min and 20 to 60 L / min, or any of 40 to 110 L / min and 65 to 110 L / min, or 40 to 80 L / min. When the flow rate of the inert gas or air is equal to or greater than the lower limit, the amount of carbon dioxide released is increased, and the time required to complete the release of carbon dioxide is shortened. When the flow rate of the inert gas or air is equal to or less than the upper limit, the evaporation of the solvent and the evaporation of the carbamic acid derivative are further suppressed.

[0047] In the carbon dioxide releasing step of the first embodiment, it is preferable to heat-treat the dispersion while supplying an inert gas or air into the dispersion at a flow rate of 20 to 110 mL / min, and the dispersion may be heat-treated while supplying nitrogen gas into the dispersion at a flow rate of 20 to 110 mL / min. In this way, the amount of carbon dioxide released is increased, and the effect of shortening the time required for the release of carbon dioxide to be completed and the effect of further suppressing the evaporation of the solvent and the evaporation of the carbamic acid derivative are remarkable.

[0048] [Ultrasonic vibration] In the carbon dioxide releasing step of the first embodiment, it is preferable to heat-treat the dispersion while applying ultrasonic vibration to the dispersion, or to heat-treat the dispersion and then apply ultrasonic vibration to the dispersion. In this way, the same effect as that obtained when the dispersion is heat-treated while supplying an inert gas or air into the dispersion can be obtained. That is, the amount of carbon dioxide released is increased, and the time required to complete the release of carbon dioxide is shortened.

[0049] When applying ultrasonic vibration to the dispersion liquid after heat treatment of the dispersion liquid, it is preferable to apply ultrasonic vibration to the dispersion liquid when the temperature of the dispersion liquid is higher than room temperature due to the heat treatment of the dispersion liquid. More specifically, it is preferable to apply ultrasonic vibration to the dispersion liquid immediately after the heat treatment of the dispersion liquid is completed, and it is more preferable to apply ultrasonic vibration to the dispersion liquid within 5 minutes after the heat treatment of the dispersion liquid is completed. In this way, the effect obtained by applying ultrasonic vibration is enhanced without impairing the effect of the heat treatment.

[0050] In the carbon dioxide releasing step of the first embodiment, the frequency of ultrasonic vibration applied to the dispersion liquid is preferably 28 to 45 kHz, which further enhances the effect obtained by applying ultrasonic vibration.

[0051] [Mixing] In the carbon dioxide releasing step of the first embodiment, it is also preferable to heat-treat the dispersion liquid while stirring, or to heat-treat the dispersion liquid and then stir it. By doing so, the same effect as that of the case where the dispersion liquid is heat-treated while supplying an inert gas or air into the dispersion liquid as described above can be obtained. That is, the amount of carbon dioxide released becomes larger, and the time required to complete the release of carbon dioxide becomes shorter.

[0052] When the dispersion is heated and then stirred, it is preferable to stir the dispersion when the temperature of the dispersion is higher than room temperature due to the heat treatment of the dispersion. More specifically, it is preferable to stir the dispersion immediately after the heat treatment of the dispersion is completed, and it is more preferable to stir the dispersion within 5 minutes after the heat treatment of the dispersion is completed. In this way, the effect obtained by stirring the dispersion is enhanced without impairing the effect of the heat treatment.

[0053] In the carbon dioxide releasing step of the first embodiment, the dispersion liquid can be stirred by a known method using, for example, a stirring blade or a stirring bar. When using a stirring blade or a stirring bar, the rotation speed can be appropriately adjusted according to, for example, the amount of the dispersion liquid used, and is not particularly limited. For example, when the amount of the dispersion liquid used is small, such as 1 L or less, the rotation speed of the stirring blade or the stirring bar is preferably 50 to 1000 rpm. In this way, the effect obtained by stirring is further enhanced.

[0054] In the carbon dioxide releasing step of the first embodiment, the stirring of the dispersion liquid may be performed, for example, by shaking the dispersion liquid by hand without using an apparatus.

[0055] The time of the carbon dioxide releasing step in the first embodiment is not particularly limited, and can be appropriately adjusted, for example, depending on other conditions, so that the amount of carbon dioxide released is maximized. The time of the carbon dioxide releasing step may be, for example, 1 to 180 minutes or 1 to 120 minutes.

[0056] In the carbon dioxide releasing step of the first embodiment, the operation of applying ultrasonic vibration to the dispersion liquid or stirring the dispersion liquid may be performed in parallel with the supply of an inert gas or air to the dispersion liquid, or may be performed without supplying an inert gas or air. Even if an inert gas or air is not supplied to the dispersion liquid, the release of the carbon dioxide from the carbamic acid derivative can be sufficiently promoted by applying ultrasonic vibration to the dispersion liquid or stirring the dispersion liquid. That is, in the carbon dioxide release process of the first embodiment, it is preferable to heat-treat the dispersion liquid while applying ultrasonic vibrations to the dispersion liquid or while stirring the dispersion liquid, or to heat-treat the dispersion liquid and then apply ultrasonic vibrations to the dispersion liquid or stir the dispersion liquid. In this case, the operation of applying ultrasonic vibrations to the dispersion liquid or stirring the dispersion liquid may be performed in parallel with the supply of an inert gas or air to the dispersion liquid, or may be performed without supplying an inert gas or air.

[0057] In the carbon dioxide releasing step of the first embodiment, the carboxyamino group in the carbamic acid derivative is converted to an amino group, and carbon dioxide is released. Then, the carboxyamino group no longer remains in the carbamic acid derivative, and the amine compound is regenerated. More specifically, IPDA is regenerated from the reaction product of IPDA and carbon dioxide, MBCHA is regenerated from the reaction product of MBCHA and carbon dioxide, and MBMCHA is regenerated from the reaction product of MBMCHA and carbon dioxide. When the compound in which at least one carboxyamino group in the carbamic acid derivative has been converted to an amino group is soluble in the solvent, the dispersion changes to a solution, and the release of carbon dioxide can be visually confirmed. Since IPDA, MBCHA, and MBMCHA are usually soluble in the solvent, when IPDA, MBCHA, or MBMCHA is regenerated from the carbamic acid derivative, the dispersion changes to a solution.

[0058] In the carbon dioxide releasing step of the first embodiment, the release of carbon dioxide from the carbamic acid derivative can be confirmed, for example, by analyzing the components in the dispersion liquid after releasing carbon dioxide (for example, the solution into which the dispersion liquid has changed) by known techniques such as nuclear magnetic resonance (NMR) spectroscopy, mass spectrometry (MS), infrared spectroscopy (IR), ultraviolet-visible spectroscopy (UV-VIS absorption spectrum), and elemental analysis.

[0059] The IPDA, MBCHA, and MBMCHA regenerated in the carbon dioxide releasing step of the first embodiment can be reacted with carbon dioxide to produce the carbamic acid derivative. In this case, the above-described method for producing the carbamic acid derivative can be applied.

[0060] <<Other processes>> The carbon dioxide releasing method of the first embodiment may include another step that does not correspond to either the dispersion liquid preparation step or the carbon dioxide releasing step, as long as the effect of the present invention is not impaired. The type and number of the other steps and the timing of performing the other steps can be arbitrarily selected depending on the purpose, and are not particularly limited.

[0061] However, the carbon dioxide releasing method of the first embodiment preferably does not have the other step between the dispersion liquid preparation step and the carbon dioxide releasing step. The carbon dioxide releasing method of the first embodiment can release carbon dioxide from the carbamic acid derivative more efficiently by continuously performing the dispersion liquid preparation step and the carbon dioxide releasing step without performing the other step between them.

[0062] Next, a carbon dioxide releasing method according to a second embodiment will be described.

[0063] Second embodiment The method for releasing carbon dioxide in the second embodiment is the same as the method for releasing carbon dioxide in the first embodiment, except that in the carbon dioxide releasing step, instead of heating the dispersion, an inert gas or air is supplied into the dispersion without heating the dispersion, thereby releasing carbon dioxide from the carbamic acid derivative.

[0064] <<Dispersion preparation process>> The dispersion preparation step of the second embodiment is the same as the dispersion preparation step of the first embodiment, and therefore a detailed description thereof will be omitted here.

[0065] <<Carbon dioxide release process>> [Inert gas, air] In the carbon dioxide releasing step after the dispersion preparation step of the second embodiment, the method of supplying an inert gas or air into the dispersion is the same as the method of supplying an inert gas or air into the dispersion in the carbon dioxide releasing step of the first embodiment. The carbon dioxide releasing step of the second embodiment may be the same as the carbon dioxide releasing step of the first embodiment in the case where an inert gas or air is supplied into the dispersion liquid, except that the dispersion liquid is not heat-treated.

[0066] For example, in the carbon dioxide releasing step of the second embodiment, examples of the inert gas supplied to the dispersion liquid include nitrogen gas, helium gas, argon gas, etc., and nitrogen gas is particularly preferred. That is, in the carbon dioxide releasing step of the second embodiment, it is preferable to heat-treat the dispersion liquid while supplying nitrogen gas to the dispersion liquid.

[0067] For example, in the carbon dioxide releasing step of the second embodiment, it is preferable to supply an inert gas or air to the dispersion liquid at a flow rate of 20 to 110 mL / min, and nitrogen gas may be supplied to the dispersion liquid at a flow rate of 20 to 110 mL / min.

[0068] <<Other processes>> The carbon dioxide releasing method of the second embodiment may include another step that does not correspond to either the dispersion liquid preparation step or the carbon dioxide releasing step, as long as the effect of the present invention is not impaired. The type and number of the other steps and the timing of performing the other steps can be arbitrarily selected depending on the purpose, and are not particularly limited. The other steps of the second embodiment may be the same as the other steps of the first embodiment, and may be performed in the same manner as the other steps of the first embodiment.

[0069] However, for the same reasons as in the case of the carbon dioxide releasing method of the first embodiment, it is preferable that the carbon dioxide releasing method of the second embodiment does not have the other steps between the dispersion liquid preparation step and the carbon dioxide releasing step. EXAMPLES

[0070] The present invention will be described in more detail below with reference to specific examples, although the present invention is not limited to the following examples.

[0071] <<Production of carbamic acid derivatives (reaction products of isophoronediamine and carbon dioxide)>> [Production Example 1] Isophoronediamine (Tokyo Chemical Industry Co., Ltd., 100 mmol) and water (100 mL) were mixed to prepare an aqueous solution of isophoronediamine with a concentration of 1 M.

[0072] The entire amount of the aqueous isophoronediamine solution obtained above was placed in a test tube, and a three-way cock was attached to the opening of the test tube. A metal thin tube was passed through the gas inlet of the three-way cock into the inside of the test tube, and the end of the thin tube on the inside side of the test tube was placed in the aqueous solution. In this way, an apparatus was assembled so that gas could be directly flowed from the outside of the test tube through the thin tube from the gas inlet of the three-way cock into the aqueous solution inside the test tube, and gas in the gas phase inside the test tube could be discharged to the outside of the test tube from the gas outlet of the three-way cock.

[0073] Next, using the above-mentioned device at room temperature, carbon dioxide gas was bubbled from the outside of the test tube into the aqueous solution inside the test tube at a flow rate of 20 mL / min, and the gas inside the test tube was discharged to the outside of the test tube through the gas outlet of the three-way cock. As time passed from the start of the inflow of carbon dioxide, a white solid was generated in the aqueous solution. This white solid was filtered out, washed with water, and dried at 60 to 90° C. to obtain a carbamic acid derivative.

[0074] The white solid obtained was a carbamic acid derivative (a reaction product of isophoronediamine and carbon dioxide) and was confirmed to be heavy water (D 2 O) in 13This was confirmed by C-NMR analysis (NMR spectrum), and the results are shown in Figure 1. From these analytical results, it was confirmed that in this carbamic acid derivative, the amino group directly bonded to the cyclohexyl group of isophoronediamine had become a carboxyamino group.

[0075] <<Carbon dioxide emissions>> [Example 1] The carbamic acid derivative (reaction product of isophoronediamine and carbon dioxide) (0.214 g, 1 mmol) obtained in Production Example 1 and methanol (15 mL) were mixed at room temperature and thoroughly stirred to obtain a methanol dispersion of the carbamic acid derivative as a carbon dioxide release agent (dispersion preparation process).

[0076] An apparatus equipped with a test tube, a three-way cock, and a metal capillary was prepared, similar to that used in the production of the carbamic acid derivative in Production Example 1. The test tube used had a diameter of 30 mm. The entire amount of the methanol dispersion of the carbamic acid derivative obtained above was placed inside the test tube in the apparatus. Next, the methanol dispersion was heated at 60°C while bubbling nitrogen gas at a flow rate of 50mL / min from the outside of the test tube into the methanol dispersion inside the test tube, and the gas inside the test tube was discharged from the gas outlet of the three-way cock to the outside of the test tube (carbon dioxide discharge step). Then, the concentration of carbon dioxide in the discharged gas was measured using a Fourier transform infrared spectrophotometer (FT-IR). The results are shown in Figure 2.

[0077] As time passed from the start of the heat treatment, the amount of insoluble components (the carbamic acid derivatives) in the methanol dispersion decreased, and the insoluble components disappeared before 90 minutes had passed. The solution after the insoluble components had disappeared was then dissolved in heavy water (D 2 O) In 13 Analysis by C-NMR confirmed that isophoronediamine had been regenerated, and the results are shown in Figure 3.

[0078] [ka]

[0079] The amount of carbon dioxide released from the start of heat treatment until 90 minutes later was 0.98 mmol. The maximum carbon dioxide release rate from the start of heat treatment until the carbon dioxide concentration reached its maximum (sometimes simply referred to as the "maximum carbon dioxide release rate" in this specification) was 101.2 μmol / min. These results are shown in Table 1, along with the carbon dioxide release conditions, the amount of carbon dioxide released, and the maximum concentration of carbon dioxide in the exhaust gas.

[0080] In addition, the "CO 2 The unit "%" next to "carbon dioxide concentration" and the unit "%" next to "maximum concentration" in Table 1 and subsequent tables both mean "volume %." The numerical values ​​(mL / mmol) in the "Solvent" column in Table 1 indicate the ratio of the amount of solvent used (mL) to the amount of carbamic acid derivative used (mmol).

[0081] [Examples 2 to 3, Reference Examples 1 to 5] A dispersion of the carbamic acid derivative was obtained in the same manner as in Example 1, except that a solvent (15 mL) shown in Table 1 was used instead of methanol (15 mL) (dispersion preparation step). In Example 2, an ethanol dispersion of the carbamic acid derivative was obtained as a carbon dioxide release agent in the same manner as in Example 1. In Example 3, a DMF dispersion of the carbamic acid derivative was obtained as a carbon dioxide release agent in the same manner as in Example 1.

[0082] Then, except for using the above-obtained dispersion liquid of the carbamic acid derivative, carbon dioxide was released (carbon dioxide releasing step) in the same manner as in Example 1. The results are shown in FIG.

[0083] [Table 1]

[0084] As is clear from the results shown in FIG. 2 and Table 1, in Examples 1 to 3, the amount of carbon dioxide released (mmol) was almost equivalent to the amount (mmol) of the carbamic acid derivative used, and it was confirmed that almost the entire amount of the carbamic acid derivative released carbon dioxide. In Examples 1 to 3, it was confirmed that the maximum concentration of carbon dioxide in the exhaust gas was 4.23% or more (4.23 to 4.54%), the maximum carbon dioxide release rate was 92.4 μmol / min or more (92.4 to 101.2 μmol / min), and almost all of the releasable carbon dioxide was released in a short period of time.

[0085] In Examples 1 to 3, the amount of insoluble components (the carbamic acid derivatives) in the dispersion decreased with time from the start of the heat treatment, and the insoluble components disappeared before 90 minutes had elapsed. The solution after the insoluble components had disappeared was dissolved in heavy water (D 2 O) In 13 Analysis by C-NMR confirmed that isophoronediamine was regenerated.

[0086] In contrast, in Reference Examples 1 to 5, both the maximum concentration of carbon dioxide in the exhaust gas and the maximum release rate of carbon dioxide were clearly inferior to Examples 1 to 3. Among Reference Examples 1 to 5, Reference Example 1 had a relatively high maximum concentration of carbon dioxide in the exhaust gas and a fast maximum release rate of carbon dioxide, but was still clearly inferior to Examples 1 to 3. Reference Examples 4 to 5 in particular had a low maximum concentration of carbon dioxide in the exhaust gas and a slow maximum release rate of carbon dioxide. Thus, Examples 1 to 3 had a significantly high carbon dioxide release capacity.

[0087] [Examples 4 to 8] As in Example 1, a methanol dispersion of a carbamic acid derivative was obtained as a carbon dioxide release agent (dispersion preparation step).

[0088] Carbon dioxide was released from the carbamic acid derivative (carbon dioxide releasing step) in the same manner as in Example 1, except that the methanol dispersion of the carbamic acid derivative was not heated instead of being heated at 60°C, that is, nitrogen gas was flowed into the methanol dispersion at room temperature (rt) to bubble it, and the concentration of carbon dioxide in the exhaust gas was measured (Example 4). When the nitrogen gas was flowed in, the temperature of the methanol dispersion was approximately 23°C. The results at this time are shown in Figure 4 together with the results of Example 1. The carbon dioxide releasing conditions, the amount of carbon dioxide released, the maximum concentration of carbon dioxide in the exhaust gas, and the maximum carbon dioxide releasing rate are shown in Table 2.

[0089] Separately, carbon dioxide was released from the carbamic acid derivative (carbon dioxide releasing step) and the concentration of carbon dioxide in the exhaust gas was measured in the same manner as in Example 1, except that the temperature of the heat treatment of the methanol dispersion of the carbamic acid derivative was 30°C (Example 5), 40°C (Example 6), 50°C (Example 7), or 70°C (Example 8) instead of 60°C. The results are shown in Figure 4. The carbon dioxide releasing conditions, the amount of carbon dioxide released, the maximum concentration of carbon dioxide in the exhaust gas, and the maximum carbon dioxide releasing rate are shown in Table 2.

[0090] [Table 2]

[0091] As is clear from the results shown in FIG. 4 and Table 2, in Examples 4 to 8, the amount of carbon dioxide released (mmol) was large, and particularly in Examples 5 to 8, the amount of carbon dioxide released (mmol) was almost equal to the amount (mmol) of the carbamic acid derivative used, confirming that almost the entire amount of the carbamic acid derivative released carbon dioxide. In Examples 4 to 8, the maximum concentration of carbon dioxide in the exhaust gas was 2.26% or more (2.26 to 5.69%), and the maximum release rate of carbon dioxide was 32.0 μmol / min or more (32.0 to 129.3 μmol / min). Of these, in Examples 4, 6 and 8, the maximum concentration of carbon dioxide in the exhaust gas was 3.10% or more (3.10 to 5.69%), and in Examples 5 to 8, the maximum release rate of carbon dioxide was 50.5 μmol / min or more (50.5 to 129.3 μmol / min).

[0092] In all of Examples 4 to 8, the amount of insoluble components (the carbamic acid derivative) in the methanol dispersion decreased with time from the start of the heat treatment. In particular, in Examples 4 and 8, the insoluble components disappeared before 90 minutes had elapsed from the start of the heat treatment. In all of Examples 4 to 8, the solutions after 90 minutes had elapsed were dissolved in heavy water (D 2 O) In 13 As a result of the C-NMR analysis, it was confirmed that isophoronediamine was regenerated, as in Example 1.

[0093] [Examples 9 to 11] A methanol dispersion of a carbamic acid derivative was obtained as a carbon dioxide release agent in the same manner as in Example 1, except that the amount of methanol used was changed from 15 mL to 1 mL (Example 9), 2 mL (Example 10), or 5 mL (Example 11). (Dispersion preparation process)

[0094] An apparatus equipped with a test tube, a three-way cock, and a metal capillary was prepared similar to that used in the production of a carbamic acid derivative in Production Example 1. However, the test tube had a diameter of 15 mm instead of 30 mm. Thereafter, carbon dioxide was released from the carbamic acid derivative (carbon dioxide releasing step) and the concentration of carbon dioxide in the exhaust gas was measured in the same manner as in Example 1, except that this device was used, the methanol dispersion of the carbamic acid derivative obtained above was used, and the temperature of the heat treatment of the methanol dispersion was 40°C instead of 60°C (Examples 9 to 11). The results are shown in Figure 5. The carbon dioxide releasing conditions, the amount of carbon dioxide released, the maximum concentration of carbon dioxide in the exhaust gas, and the maximum carbon dioxide releasing rate are shown in Table 3.

[0095] [Examples 12 to 14] A methanol dispersion of a carbamic acid derivative was obtained as a carbon dioxide release agent in the same manner as in Example 1, except that the amount of methanol used was 5 mL (Example 12), 10 mL (Example 113), or 20 mL (Example 14) instead of 15 mL (dispersion preparation process).

[0096] Carbon dioxide was released from the carbamic acid derivative (carbon dioxide releasing step) and the concentration of carbon dioxide in the exhaust gas was measured in the same manner as in Example 1 (Examples 12 to 15), except that the methanol dispersion of the carbamic acid derivative obtained above was used and the temperature of the heat treatment of the methanol dispersion was 40°C instead of 60°C. The results are shown in Figure 5 together with the results of Example 6. The carbon dioxide releasing conditions, the amount of carbon dioxide released, the maximum concentration of carbon dioxide in the exhaust gas, and the maximum carbon dioxide releasing rate are shown in Table 3.

[0097] [Table 3]

[0098] As is clear from the results shown in FIG. 5 and Table 3, in Examples 9 to 14, the amount of carbon dioxide released (mmol) was almost equivalent to the amount (mmol) of the carbamic acid derivative used, and it was confirmed that almost the entire amount of the carbamic acid derivative released carbon dioxide. In Examples 9 to 14, the maximum concentration of carbon dioxide in the exhaust gas was 2.81% or more (2.81 to 5.86%), and the maximum carbon dioxide release rate was 62.6 μmol / min or more (62.6 to 130.9 μmol / min). Among them, in Examples 10 to 14, the maximum concentration of carbon dioxide in the exhaust gas was 3.02% or more (3.02 to 5.86%).

[0099] From the comparison of Examples 11 and 12, it was confirmed that when the amount of the methanol dispersion of the carbamic acid derivative was the same, the maximum carbon dioxide release rate was significantly increased when a test tube with a smaller diameter was used. This was presumed to be because when nitrogen gas was introduced into the dispersion and bubbled, the width of the nitrogen gas flow path became narrower, increasing the amount of the methanol dispersion in contact with the nitrogen gas, and the nitrogen gas was used efficiently.

[0100] In all of Examples 9 to 14, the amount of insoluble components (the carbamic acid derivatives) in the methanol dispersion decreased with time from the start of the heat treatment. After the insoluble components had disappeared, the solution was dissolved in heavy water (D 2 O) In 13 Analysis by C-NMR confirmed that isophoronediamine was regenerated.

[0101] [Examples 15 to 17] A methanol dispersion of a carbamic acid derivative was obtained as a carbon dioxide release agent in the same manner as in Example 1, except that the amount of methanol used was 2 mL instead of 15 mL (dispersion preparation step).

[0102] An apparatus equipped with a test tube, a three-way cock, and a metal capillary was prepared similar to that used in the production of a carbamic acid derivative in Production Example 1. However, the test tube had a diameter of 15 mm instead of 30 mm. Hereafter, carbon dioxide was released from the carbamic acid derivative (carbon dioxide releasing step) and the concentration of carbon dioxide in the exhaust gas was measured (Examples 15 to 17) in the same manner as in Example 1, except that this device was used, the above-obtained carbamic acid derivative methanol dispersion was used, the flow rate of nitrogen gas flowing into the above-obtained carbamic acid derivative methanol dispersion was changed from 50 mL / min to 25 mL / min (Example 15), 75 mL / min (Example 16), or 100 mL / min (Example 17), and the temperature of the heat treatment of the above-obtained methanol dispersion was changed from 60 ° C to 40 ° C. The results at this time are shown in FIG. 6 together with the results of Example 10. The carbon dioxide release conditions, the amount of carbon dioxide released, the maximum concentration of carbon dioxide in the exhaust gas, and the maximum carbon dioxide release rate are shown in Table 4.

[0103] [Table 4]

[0104] As is clear from the results shown in FIG. 6 and Table 4, in Examples 15 to 17, the amount of carbon dioxide released (mmol) was almost equivalent to the amount (mmol) of the carbamic acid derivative used, and it was confirmed that almost the entire amount of the carbamic acid derivative released carbon dioxide. In Examples 15 to 17, the maximum concentration of carbon dioxide in the exhaust gas was 3.66% or more (3.66 to 5.78%), and the maximum carbon dioxide release rate was 64.5 μmol / min or more (64.5 to 163.4 μmol / min). Among them, in Examples 16 to 17, the maximum carbon dioxide release rate was 129.7 μmol / min or more (129.7 to 163.4 μmol / min).

[0105] In all of Examples 15 to 17, the amount of insoluble components (the carbamic acid derivatives) in the methanol dispersion decreased with time from the start of the heat treatment. After the insoluble components had disappeared, the solution was dissolved in heavy water (D 2 O) In 13Analysis by C-NMR confirmed that isophoronediamine was regenerated.

[0106] From the above results of Examples 15 to 17 and Example 10, it was confirmed that there is a tendency that as the flow rate of nitrogen gas increases, the maximum concentration of carbon dioxide in the exhaust gas decreases and the maximum release rate of carbon dioxide increases.

[0107] [Example 18] A methanol dispersion of a carbamic acid derivative was obtained as a carbon dioxide release agent in the same manner as in Example 1, except that the amount of methanol used was 5 mL instead of 15 mL (dispersion preparation step).

[0108] An apparatus equipped with a test tube, a three-way cock, and a metal capillary was prepared similar to that used in the production of a carbamic acid derivative in Production Example 1. However, the test tube had a diameter of 15 mm instead of 30 mm. Hereafter, carbon dioxide was released from the carbamic acid derivative (carbon dioxide releasing step) and the concentration of carbon dioxide in the exhaust gas was measured in the same manner as in Example 1, except that this device was used, the above-obtained methanol dispersion of the carbamic acid derivative was used, the temperature of the heat treatment of the methanol dispersion was 40°C instead of 60°C, and the flow rate of the nitrogen gas flowing into the methanol dispersion of the carbamic acid derivative was 100mL / min instead of 50mL / min. The carbon dioxide releasing conditions, the amount of carbon dioxide released, the maximum concentration of carbon dioxide in the exhaust gas, and the maximum carbon dioxide releasing rate are shown in Table 5 together with those in Example 11.

[0109] [Table 5]

[0110] As is clear from the results shown in Table 5, in Example 18, the amount of carbon dioxide released (mmol) was almost equivalent to the amount (mmol) of the carbamic acid derivative used, and it was confirmed that almost the entire amount of the carbamic acid derivative released carbon dioxide.

[0111] In Example 18, the amount of insoluble components (the carbamic acid derivative) in the methanol dispersion decreased with time from the start of the heat treatment. 2 O) In 13 Analysis by C-NMR confirmed that isophoronediamine was regenerated.

[0112] From the above results of Examples 18 and 11, it was confirmed that as the flow rate of nitrogen gas increases, the maximum concentration of carbon dioxide in the exhaust gas tends to decrease and the maximum release rate of carbon dioxide tends to increase.

[0113] [Examples 19 to 21] As in Example 3, a DMF dispersion of a carbamic acid derivative was obtained as a carbon dioxide release agent (dispersion preparation step).

[0114] Carbon dioxide was released from the carbamic acid derivative (carbon dioxide releasing step) and the concentration of carbon dioxide in the exhaust gas was measured in the same manner as in Example 3, except that the temperature of the heat treatment of the DMF dispersion of the carbamic acid derivative was 40°C (Example 19), 80°C (Example 20), or 100°C (Example 21) instead of 60°C. The results are shown in Figure 7 together with the results of Example 3. The carbon dioxide releasing conditions, the amount of carbon dioxide released, the maximum concentration of carbon dioxide in the exhaust gas, and the maximum carbon dioxide releasing rate are shown in Table 6.

[0115] [Table 6]

[0116] As is clear from the results shown in FIG. 7 and Table 6, in Examples 19 to 21, the amount of carbon dioxide released (mmol) was large, and particularly in Examples 20 to 21, the amount of carbon dioxide released (mmol) was almost equivalent to the amount (mmol) of the carbamic acid derivative used, confirming that almost the entire amount of the carbamic acid derivative released carbon dioxide. In Examples 19 to 21, the maximum concentration of carbon dioxide in the exhaust gas was 1.21% or more (1.21 to 6.18%), and the maximum release rate of carbon dioxide was 27.0 μmol / min or more (27.0 to 138.0 μmol / min). Among them, in Examples 20 to 21, the maximum concentration of carbon dioxide in the exhaust gas was 5.79% or more (5.79 to 6.18%), and the maximum release rate of carbon dioxide was 129.3 μmol / min or more (129.3 to 138.0 μmol / min).

[0117] In all of Examples 19 to 21, the amount of insoluble components (the carbamic acid derivative) in the DMF dispersion decreased with time from the start of the heat treatment. In particular, in Examples 20 to 21, the insoluble components disappeared before 90 minutes had elapsed from the start of the heat treatment. In all of Examples 19 to 21, the solutions after 90 minutes had elapsed were dissolved in heavy water (D 2 O) In 13 As a result of the C-NMR analysis, it was confirmed that isophoronediamine was regenerated, as in Example 3.

[0118] From the above results of Examples 19 to 21 and Example 3, it was confirmed that as the temperature of the heat treatment of the DMF dispersion increases, the maximum concentration of carbon dioxide in the exhaust gas increases and the maximum carbon dioxide release rate tends to increase.

[0119] [Examples 22 to 24] A DMF dispersion of a carbamic acid derivative was obtained as a carbon dioxide release agent in the same manner as in Example 3, except that the amount of DMF used was 5 mL (Example 22), 10 mL (Example 23), or 20 mL (Example 24) instead of 15 mL (dispersion preparation process).

[0120] Except for using the DMF dispersion of the carbamic acid derivative obtained above, carbon dioxide was released from the carbamic acid derivative (carbon dioxide releasing step) and the concentration of carbon dioxide in the exhaust gas was measured in the same manner as in Example 3 (Examples 22 to 24). The results are shown in FIG. 8 together with the results of Example 3. The carbon dioxide releasing conditions, the amount of carbon dioxide released, the maximum concentration of carbon dioxide in the exhaust gas, and the maximum carbon dioxide releasing rate are shown in Table 7.

[0121] [Examples 25 to 26] A DMF dispersion of a carbamic acid derivative was obtained as a carbon dioxide release agent in the same manner as in Example 3, except that the amount of DMF used was changed from 15 mL to 30 mL (Example 25) or 50 mL (Example 26) (dispersion preparation process).

[0122] An apparatus equipped with a container, a three-way cock, and a metal capillary was prepared similar to that used in producing a carbamic acid derivative in Production Example 1. However, as the container, a 100 mL eggplant-shaped flask was used instead of a 30 mm diameter test tube. Thereafter, carbon dioxide was released from the carbamic acid derivative (carbon dioxide releasing step) and the concentration of carbon dioxide in the exhaust gas was measured (Examples 25 to 26) in the same manner as in Example 3, except that this device was used and the DMF dispersion of the carbamic acid derivative obtained above was used (Examples 25 to 26). The results are shown in Figure 8. The carbon dioxide releasing conditions, the amount of carbon dioxide released, the maximum concentration of carbon dioxide in the exhaust gas, and the maximum carbon dioxide releasing rate are shown in Table 7.

[0123] [Table 7]

[0124] As is clear from the results shown in FIG. 8 and Table 7, in Examples 22 to 26, the amount of carbon dioxide released (mmol) was large, and particularly in Examples 23 to 26, the amount of carbon dioxide released (mmol) was almost equivalent to the amount (mmol) of the carbamic acid derivative used, confirming that almost the entire amount of the carbamic acid derivative released carbon dioxide. In Examples 22 to 26, the maximum concentration of carbon dioxide in the exhaust gas was 2.62% or more (2.62 to 4.24%), and the maximum release rate of carbon dioxide was 58.5 μmol / min or more (58.5 to 94.5 μmol / min). Of these, in Examples 24 to 26, the maximum concentration of carbon dioxide in the exhaust gas was 3.40% or more (3.40 to 4.24%), and the maximum release rate of carbon dioxide was 70.0 μmol / min or more (70.0 to 94.5 μmol / min).

[0125] In all of Examples 22 to 26, the amount of insoluble components (the carbamic acid derivatives) in the dispersion decreased with time from the start of the heat treatment, and the insoluble components disappeared before 90 minutes had elapsed. The solution after the insoluble components had disappeared was dissolved in heavy water (D 2 O) In 13 Analysis by C-NMR confirmed that isophoronediamine was regenerated.

[0126] [Examples 27 to 29] As in Example 3, a DMF dispersion of a carbamic acid derivative was obtained as a carbon dioxide release agent (dispersion preparation step).

[0127] Carbon dioxide was released from the carbamic acid derivative (carbon dioxide releasing step) and the concentration of carbon dioxide in the exhaust gas was measured (Examples 27 to 29) in the same manner as in Example 3, except that the flow rate of the nitrogen gas flowing into the methanol dispersion of the carbamic acid derivative obtained above was changed from 50 mL / min to 25 mL / min (Example 27), 75 mL / min (Example 28), or 100 mL / min (Example 29). The results of Examples 27 and 29 are shown in FIG. 9 together with the results of Example 3. The carbon dioxide releasing conditions, the amount of carbon dioxide released, the maximum concentration of carbon dioxide in the exhaust gas, and the maximum carbon dioxide releasing rate in Examples 27 to 29 are shown in Table 8.

[0128] [Table 8]

[0129] As is clear from the results shown in FIG. 9 and Table 8, in Examples 27 to 29, the amount of carbon dioxide released (mmol) was almost equivalent to the amount (mmol) of the carbamic acid derivative used, and it was confirmed that almost the entire amount of the carbamic acid derivative released carbon dioxide. In Examples 27 to 29, the maximum concentration of carbon dioxide in the exhaust gas was 2.88% or more (2.88 to 4.87%), and the maximum release rate of carbon dioxide was 40.4 μmol / min or more (40.4 to 131.3 μmol / min). Of these, in Examples 27 to 28, the maximum concentration of carbon dioxide in the exhaust gas was 3.72% or more (3.72 to 4.87%), and in Examples 28 to 29, the maximum release rate of carbon dioxide was 128.5 μmol / min or more (128.5 to 131.3 μmol / min).

[0130] In all of Examples 27 to 29, the amount of insoluble components (the carbamic acid derivative) in the methanol dispersion decreased with time from the start of the heat treatment. In particular, in Example 29, the insoluble components disappeared before 90 minutes had elapsed from the start of the heat treatment. In all of Examples 27 to 29, the solutions after 90 minutes had elapsed were dissolved in heavy water (D2 O) In 13 As a result of the C-NMR analysis, it was confirmed that isophoronediamine was regenerated, as in Example 3.

[0131] From the above results of Examples 27 to 29 and Example 3, it was confirmed that there is a tendency that as the flow rate of nitrogen gas increases, the maximum concentration of carbon dioxide in the exhaust gas decreases and the maximum release rate of carbon dioxide increases.

[0132] [Example 30] As in Example 1, a methanol dispersion of a carbamic acid derivative was obtained as a carbon dioxide release agent (dispersion preparation step).

[0133] The entire amount of the methanol dispersion of the carbamic acid derivative obtained above was placed in a test tube having a diameter of 30 mm. Next, the test tube was immersed in hot water at 70° C. for 10 seconds, and then removed from the hot water, and the methanol dispersion was immediately (within 3 seconds) stirred by shaking with hands (carbon dioxide releasing step). As a result, foaming occurred in the methanol dispersion. This foaming was due to the release of carbon dioxide from the carbamic acid derivative, and after foaming, the methanol dispersion had become a transparent solution with the insoluble components disappearing. The solution after the insoluble components had disappeared was dissolved in heavy water (D 2 O) In 13 Analysis by C-NMR confirmed that isophoronediamine was regenerated.

[0134] [Example 31] The carbamic acid derivative (reaction product of isophoronediamine and carbon dioxide) (1.07 g, 5 mmol) obtained in Production Example 1 and methanol (25 mL) were mixed at room temperature and thoroughly stirred to obtain a methanol dispersion of the carbamic acid derivative as a carbon dioxide release agent (dispersion preparation process).

[0135] The entire amount of the methanol dispersion of the carbamic acid derivative obtained above was placed in a test tube having a diameter of 30 mm, and a balloon was attached to the opening of the test tube. Next, the test tube was immersed in hot water at 90° C. for 10 minutes, then removed from the hot water and allowed to cool to room temperature (carbon dioxide release step). As a result, foaming occurred in the methanol dispersion. This foaming was due to the release of carbon dioxide from the carbamic acid derivative, and after foaming, the insoluble components disappeared from the methanol dispersion, turning it into a transparent solution. At the same time, the balloon attached to the opening of the test tube was inflated, and approximately 24 mL of gas was collected. This gas was the released carbon dioxide. The solution after the insoluble components had disappeared was then immersed in heavy water (D 2 O) In 13 Analysis by C-NMR confirmed that isophoronediamine was regenerated.

[0136] As a comparative experiment, a similar experiment was carried out using only methanol (25 mL) instead of the above-mentioned methanol dispersion of the carbamic acid derivative, and the balloon attached to the opening of the test tube remained deflated and did not expand. In other words, in this comparative experiment, almost no methanol was evaporated.

[0137] [Example 32] Carbon dioxide was released in the same manner as in Example 31, except that the heating temperature of the methanol dispersion was 75° C. instead of 90° C. (dispersion preparation step, carbon dioxide release step). As a result, as in Example 31, carbon dioxide was released from the carbamic acid derivative, causing foaming in the methanol dispersion, and after foaming, the insoluble components disappeared from the methanol dispersion, turning it into a transparent solution. At the same time, the balloon attached to the opening of the test tube was inflated, and approximately 5.5 mL of gas was collected. This gas was the released carbon dioxide. The solution after the insoluble components had disappeared was then dissolved in heavy water (D 2 O) In 13 Analysis by C-NMR confirmed that isophoronediamine was regenerated.

[0138] As a comparative experiment, a similar experiment was carried out using only methanol (25 mL) instead of the above-mentioned methanol dispersion of the carbamic acid derivative, and the balloon attached to the opening of the test tube remained deflated and did not expand. In other words, in this comparative experiment, almost no methanol was evaporated.

[0139] <<Production of carbamic acid derivatives (reaction products of 4,4'-methylenebis(cyclohexylamine) and carbon dioxide)>> [Production Example 2] An aqueous MBCHA solution with a concentration of 1 M was prepared by mixing 4,4'-methylenebis(cyclohexylamine) (MBCHA, manufactured by Tokyo Chemical Industry Co., Ltd., 1 mmol) and water (2 mL).

[0140] The same apparatus as that used in Production Example 1 was prepared, and the entire amount of the aqueous MBCHA solution obtained above was placed in a test tube in this apparatus. Next, a mixed gas containing carbon dioxide and nitrogen with a carbon dioxide concentration of approximately 400 ppm by volume was bubbled into the aqueous solution inside the test tube from outside the test tube at a flow rate of 20 mL / min at room temperature, while the gas inside the test tube was discharged to the outside of the test tube through the gas outlet of the three-way cock. As time passed from the start of the inflow of carbon dioxide, a white solid was generated in the aqueous solution. This white solid was filtered out, washed with water, and dried at 60 to 90° C. to obtain a carbamic acid derivative.

[0141] The obtained white solid (carbamic acid derivative) was analyzed using FT-IR. The results are shown in Figure 10 together with the analysis results of 4,4'-methylenebis(cyclohexylamine) (MBCHA). Figure 10(a) shows the spectral data in the wavelength range of 4000 nm or less, and Figure 10(b) shows the expanded spectral data in the wavelength range of 1500 to 1700 nm.

[0142] From these analytical results, it was confirmed that this carbamic acid derivative is one in which one of the two amino groups directly bonded to the cyclohexyl group of MBCHA has become a carboxyamino group.

[0143] <<Carbon dioxide emissions>> [Example 33] The carbamic acid derivative (reaction product of 4,4'-methylenebis(cyclohexylamine) and carbon dioxide) (1 mmol) obtained in Production Example 2 was mixed with methanol (2 mL) at room temperature and thoroughly stirred to obtain a methanol dispersion of the carbamic acid derivative as a carbon dioxide release agent (dispersion preparation process).

[0144] An apparatus equipped with a test tube, a three-way cock, and a metal capillary was prepared similar to that used in the production of a carbamic acid derivative in Production Example 1. However, the test tube had a diameter of 15 mm instead of 30 mm. Thereafter, carbon dioxide was released from the carbamic acid derivative (carbon dioxide releasing step) and the concentration of carbon dioxide in the exhaust gas was measured in the same manner as in Example 1, except that this device was used, the methanol dispersion of the carbamic acid derivative obtained above was used, and the temperature of the heat treatment of the methanol dispersion was 40°C instead of 60°C. The results are shown in Figure 11. The carbon dioxide releasing conditions, the amount of carbon dioxide released, the maximum concentration of carbon dioxide in the exhaust gas, and the maximum carbon dioxide releasing rate are shown in Table 9.

[0145] [Example 34] A methanol dispersion of a carbamic acid derivative was obtained as a carbon dioxide release agent in the same manner as in Example 33, except that the amount of methanol used was 5 mL instead of 2 mL (dispersion preparation step).

[0146] Except for using the methanol dispersion of the carbamic acid derivative obtained above, carbon dioxide was released from the carbamic acid derivative (carbon dioxide releasing step) and the concentration of carbon dioxide in the exhaust gas was measured in the same manner as in Example 33. The results are shown in FIG. 11 together with the results of Example 33. The carbon dioxide releasing conditions, the amount of carbon dioxide released, the maximum concentration of carbon dioxide in the exhaust gas, and the maximum carbon dioxide releasing rate are shown in Table 9.

[0147] [ka]

[0148] [Table 9]

[0149] As is clear from the results shown in FIG. 11 and Table 9, in Examples 33 and 34, it was confirmed that the amount of carbon dioxide released (mmol) increased with an increase in the amount of methanol used. In Examples 33 and 34, the maximum concentration of carbon dioxide in the exhaust gas was 1.36% or more (1.36 to 2.64%), and the maximum carbon dioxide release rate was 30.0 μmol / min or more (30.0 to 59.0 μmol / min).

[0150] In all of Examples 33 to 34, the amount of insoluble components (the carbamic acid derivative) in the methanol dispersion decreased with time from the start of the heat treatment. In all of Examples 33 to 34, the solution after 90 minutes was dissolved in heavy water (D 2 O) In 13 Analysis by C-NMR confirmed that 4,4'-methylenebis(cyclohexylamine) was regenerated.

[0151] <<Production of carbamic acid derivatives (reaction products of 4,4'-methylenebis(2-methylcyclohexylamine) with carbon dioxide)>> [Production Example 3] An aqueous MBMCHA solution with a concentration of 1 M was prepared by mixing 4,4'-methylenebis(2-methylcyclohexylamine) (MBMCHA, manufactured by Tokyo Chemical Industry Co., Ltd., 1 mmol) and water (2 mL).

[0152] The same apparatus as that used in Production Example 1 was prepared, and the entire amount of the aqueous MBMCHA solution obtained above was placed in a test tube in this apparatus. Next, a mixed gas containing carbon dioxide and nitrogen with a carbon dioxide concentration of approximately 400 ppm by volume was bubbled into the aqueous solution inside the test tube from outside the test tube at a flow rate of 20 mL / min at room temperature, while the gas inside the test tube was discharged to the outside of the test tube through the gas outlet of the three-way cock. As time passed from the start of the inflow of carbon dioxide, a white solid was generated in the aqueous solution. This white solid was filtered out, washed with water, and dried at 60 to 90° C. to obtain a carbamic acid derivative.

[0153] The obtained white solid (carbamic acid derivative) was analyzed using FT-IR. The results are shown in Figure 12 together with the analysis results of 4,4'-methylenebis(2-methylcyclohexylamine) (MBMCHA). Figure 12(a) shows the spectral data in the wavelength range of 4000 nm or less, and Figure 12(b) shows the expanded spectral data in the wavelength range of 1500 to 1700 nm.

[0154] From these analytical results, it was confirmed that in this carbamic acid derivative, one of the two amino groups directly bonded to the cyclohexyl group of MBMCHA had become a carboxyamino group.

[0155] <<Carbon dioxide emissions>> [Example 35] The carbamic acid derivative (reaction product of 4,4'-methylenebis(2-methylcyclohexylamine)) and carbon dioxide) (1 mmol) obtained in Production Example 3 was mixed with methanol (2 mL) at room temperature and thoroughly stirred to obtain a methanol dispersion of the carbamic acid derivative as a carbon dioxide release agent (dispersion preparation process).

[0156] An apparatus equipped with a test tube, a three-way cock, and a metal capillary was prepared similar to that used in the production of a carbamic acid derivative in Production Example 1. However, the test tube had a diameter of 15 mm instead of 30 mm. Thereafter, carbon dioxide was released from the carbamic acid derivative (carbon dioxide releasing step) and the concentration of carbon dioxide in the exhaust gas was measured in the same manner as in Example 1, except that this device was used, the methanol dispersion of the carbamic acid derivative obtained above was used, and the temperature of the heat treatment of the methanol dispersion was 40°C instead of 60°C. The results are shown in Figure 13. The carbon dioxide releasing conditions, the amount of carbon dioxide released, the maximum concentration of carbon dioxide in the exhaust gas, and the maximum carbon dioxide releasing rate are shown in Table 10.

[0157] [Example 36] A methanol dispersion of a carbamic acid derivative was obtained as a carbon dioxide release agent in the same manner as in Example 35, except that the amount of methanol used was 5 mL instead of 2 mL (dispersion preparation step).

[0158] Except for using the methanol dispersion of the carbamic acid derivative obtained above, carbon dioxide was released from the carbamic acid derivative (carbon dioxide releasing step) and the concentration of carbon dioxide in the exhaust gas was measured in the same manner as in Example 35. The results are shown in FIG. 13 together with the results of Example 35. The carbon dioxide releasing conditions, the amount of carbon dioxide released, the maximum concentration of carbon dioxide in the exhaust gas, and the maximum carbon dioxide releasing rate are shown in Table 10.

[0159] [ka]

[0160] [Table 10]

[0161] 13 and Table 10, it was confirmed that the amount of carbon dioxide released (mmol) increased with an increase in the amount of methanol used in Examples 35 and 36. In particular, in Example 36, it was confirmed that the amount of carbon dioxide released (mmol) was almost equal to the amount of carbamic acid derivative used (mmol), and almost the entire amount of the carbamic acid derivative released carbon dioxide. In Examples 35 and 36, the maximum concentration of carbon dioxide in the exhaust gas was 4.40% or more (4.40 to 4.65%), and the maximum carbon dioxide release rate was 98.2 μmol / min or more (98.2 to 103.7 μmol / min).

[0162] In all of Examples 35 to 36, the amount of insoluble components (the carbamic acid derivative) in the methanol dispersion decreased with time from the start of the heat treatment. In all of Examples 35 to 36, the solution after 90 minutes was dissolved in heavy water (D 2 O) In 13 Analysis by C-NMR confirmed that 4,4'-methylenebis(2-methylcyclohexylamine) was regenerated. [Industrial Applicability]

[0163] The present invention can be used in the general field of carbon dioxide capture.

Claims

1. A method for releasing carbon dioxide, comprising: The method for releasing carbon dioxide includes the steps of: preparing a dispersion by dispersing a reaction product of carbon dioxide and one or more members selected from the group consisting of isophoronediamine, 4,4'-methylenebis(cyclohexylamine) and 4,4'-methylenebis(2-methylcyclohexylamine) in one solvent or a mixed solvent of two or more members selected from the group consisting of methanol, ethanol and N,N-dimethylformamide; and releasing the carbon dioxide from the reaction product by heat-treating the dispersion, or by supplying an inert gas or air into the dispersion without heating the dispersion.

2. 2. The method for releasing carbon dioxide according to claim 1, wherein in the step of releasing carbon dioxide, the dispersion is heat-treated while supplying nitrogen gas into the dispersion.

3. 3. The method for releasing carbon dioxide according to claim 1 or 2, wherein in the step of releasing carbon dioxide, the dispersion is heat-treated while applying ultrasonic vibrations to the dispersion or while stirring the dispersion, or the dispersion is heat-treated and then ultrasonic vibrations are applied to the dispersion or the dispersion is stirred.

4. The method for releasing carbon dioxide according to claim 1 or 2, wherein in the step of releasing carbon dioxide, the dispersion is heat-treated without supplying the inert gas or air.

5. 3. The method for releasing carbon dioxide according to claim 1, wherein the dispersion is heat-treated at a heating temperature of 60° C. or lower.

6. 3. The method for releasing carbon dioxide according to claim 1 or 2, wherein the inert gas or air is supplied to the dispersion liquid at a flow rate of 20 to 110 mL / min.

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