Water treatment system, water treatment method, and amine solution

Abstract

To provide an effective water treatment system and method.SOLUTION: A method includes a process of mixing treatment water and amine solution, separating the mixture into phases to produce a supernatant phase and a concentration phase. The amine solution includes a chemical compound according to the equation (1) or / and (2) (R1, R4 are a linear alkyl chain of C2-6 or the like, and R2, R3, R5-R7 are a hydrocarbon group of C1-6).SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] SUMMARY OF THE INVENTION Embodiments of the present invention relate to water treatment systems and methods and amine solutions. [Background technology]

[0002] As the global population grows, demand for water is expected to grow significantly, creating a need for low-energy desalination technologies. Common desalination methods include thermal evaporation and reverse osmosis (RO) membranes, with the RO membrane method, which consumes relatively little energy, coming into widespread use in recent years. The reverse osmosis membrane method desalinates by applying pressure to an osmotic membrane in the opposite direction to the osmotic pressure. [Prior art documents] [Non-patent literature]

[0003] [Non-Patent Document 1] Environ.Sci.Technol. 2020, 54 9124-9131 Summary of the Invention [Problem to be solved by the invention]

[0004] Embodiments provide a water treatment system, a water treatment method, and an amine solution that efficiently treat water. [Means for solving the problem]

[0005] The water treatment system of the embodiment includes a means for introducing water to be treated into a first container, a means for introducing an amine solution into the first container to obtain a first mixture, and a means for separating the supernatant and concentrated phases of a second mixture resulting from phase separation of the first mixture. The amine solution contains an amine compound of chemical formula (1) and / or chemical formula (2), and R of chemical formula (1) 1is a linear alkyl chain having 2 to 6 carbon atoms, a branched alkyl chain having 4 to 6 carbon atoms, a cyclic alkyl chain having 5 or 6 carbon atoms, an ether chain having 2 to 6 carbon atoms, or an aminoalkyl chain having 2 to 9 carbon atoms, and R in the chemical formula (1) 2 is a hydrocarbon group having 1 to 6 carbon atoms, and R in chemical formula (1) 3 is a hydrocarbon group having 1 to 6 carbon atoms, and in chemical formula (1), [number of carbon atoms in the molecule] / [number of nitrogen atoms in the molecule] is 4.0 or more and 7.0 or less, and R in chemical formula (2) 4 is a linear alkyl chain having 2 to 6 carbon atoms, a branched alkyl chain having 4 to 6 carbon atoms, a cyclic alkyl chain having 5 or 6 carbon atoms, an ether chain having 2 to 6 carbon atoms, or an aminoalkyl chain having 2 to 9 carbon atoms, and R in the chemical formula (2) 5 is a hydrocarbon group having 1 to 6 carbon atoms, and R in chemical formula (2) 6 is a hydrocarbon group having 1 to 6 carbon atoms, and R in chemical formula (2) 7 is a hydrocarbon group having 1 to 6 carbon atoms, and in chemical formula (2), [number of carbon atoms in the molecule] / [number of nitrogen atoms in the molecule] is 4.0 or more and 7.0 or less. [Brief explanation of the drawings]

[0006] [Figure 1] 1 is a schematic diagram of a water treatment system according to an embodiment. [Figure 2] 1 is a flowchart of a water treatment method according to an embodiment. [Figure 3] 1 shows the chemical formula of an amine compound according to an embodiment. [Figure 4] 1 shows the chemical formula of an amine compound according to an embodiment. [Figure 5] 1 is a schematic diagram of a water treatment system according to an embodiment. [Figure 6] 1 is a flowchart of a water treatment method according to an embodiment. [Figure 7] 1 is a schematic diagram of a water treatment system according to an embodiment. [Figure 8] 1 is a flowchart of a water treatment method according to an embodiment. [Figure 9] Table of Examples. [Figure 10] Table of Examples. [Figure 11] Table of Examples. DETAILED DESCRIPTION OF THE INVENTION

[0007] DETAILED DESCRIPTION OF THE INVENTION

[0023] An embodiment of the present invention will now be described with reference to the accompanying drawings. Unless otherwise specified, values ​​obtained by pH and other measurements are values ​​measured at atmospheric pressure and 25°C.

[0008] Hereinafter, in the description of compounds with chemical formulas, chemical bonds may be indicated with hyphens.

[0009] Water treatment embodiments relate to the concentration and recovery (including precipitation) and / or production (eg, desalination) of water from target water.

[0010] (First embodiment) The first embodiment relates to a water treatment system, a water treatment method, and an amine solution that are applied to non-evaporative extraction and separation by concentration using an amine compound whose hydrophobicity and hydrophilicity change with temperature. Figure 1 shows a schematic diagram of a water treatment system 100 of the first embodiment. The schematic diagram of the water treatment system 100 in Figure 1 includes a means 11 for introducing water to be treated A into a first container B, a means 12 for introducing an amine solution C into the first container B to obtain a first mixture D, a temperature control means 13 for controlling the temperature, and a means 14 for separating a supernatant phase F (liquid phase) from a concentrated phase G (liquid phase, solid phase, or slurry phase) of a second mixture E, which is a phase-separated mixture D containing the water to be treated A and the amine solution C. The second mixture E undergoes phase separation at low temperatures.

[0011] In the present embodiment, "phase separation" and "a state in which an organic phase and an aqueous phase are separated" refer to, for example, a state in which a mixture of water and an amine solution is phase-separated into an organic phase and an aqueous phase, in other words, a relationship in which the boundary between the organic phase and the aqueous phase can be visually confirmed. The boundary between the organic phase and the aqueous phase can also be recognized from the difference in refractive index. In the present embodiment, the organic phase, in the phase-separated state, is a phase mainly composed of an amine compound and contains a high concentration of the amine compound. The aqueous phase, in the phase-separated state, is a phase mainly composed of water. At low temperatures, the amine solution dissolves in water in a high amount, and the amine compound dissolves in the aqueous solution. In this state, the amine solution does not separate into an organic phase and an aqueous phase. At high temperatures, the solubility of the amine compound in water decreases, and the amine solution separates into an aqueous phase and an organic phase containing a high concentration of the amine compound. When phase separation occurs, typically, an organic phase and an aqueous phase form a complete two-phase system. However, in this embodiment, even if complete phase separation does not occur, the system is referred to as "two-phase system" as long as the phase boundary can be confirmed.

[0012] In the schematic diagram of Figure 1, means 11 for introducing the water to be treated A into the first container B, means 12 for introducing the amine solution C into the first container B to obtain a first mixture D, temperature control means 13 for controlling the temperature, and means 14 for separating the supernatant phase F and concentrated phase G of the second mixture E obtained by phase separation of the first mixture D containing the water to be treated A and the amine solution C are provided outside the first container B, but these means may also be provided inside the first container B.

[0013] FIG. 2 shows a flowchart of a water treatment method according to a first embodiment. The water treatment method of the embodiment preferably includes the steps of: obtaining a first mixture D by mixing water to be treated A and an amine solution C; phase-separating the first mixture D at a low temperature to obtain a phase-separated second mixture E; and separating a supernatant phase F and a concentrated phase G of the phase-separated second mixture E. The step of mixing water to be treated A and amine solution C to obtain the first mixture D is performed by means 11 for introducing water to be treated A into a first container B and means 12 for introducing amine solution C into the first container B to obtain the first mixture D. By storing the first mixture D at a low temperature in the first container B, the first mixture D undergoes phase separation, resulting in a phase-separated second mixture E. The first container B for mixing water to be treated A and amine solution C and the container for storing the first mixture D when the first mixture D undergoes phase separation may be the same container or different containers. The step of separating the supernatant phase F and concentrated phase G of the phase-separated second mixture E is performed by means 14 for separating the supernatant phase F and concentrated phase G of the second mixture resulting from phase separation of the first mixture D containing the water to be treated A and the amine solution C. The water treatment system 100 will be described below, and the description of the water treatment system 100 also includes a description of the water treatment method.

[0014] The means 11 for introducing the water to be treated A into the first container B introduces the water to be treated A into the first container B. The means 11 for introducing the water to be treated A into the first container B includes, for example, a pipe leading to the first container B, and instruments for determining the properties of the water to be treated A, such as a water quality measuring instrument such as a pH meter or a conductivity meter, a thermometer, and valves, cocks, and pumps for controlling the flow rate of the water to be treated A flowing through the pipe.

[0015] The water to be treated A contains water and inorganic salts soluble in water and / or organic matter soluble in water. The inorganic salts soluble in water and / or organic matter soluble in water are separated by the water treatment system 100 of the embodiment. The inorganic salts and / or organic matter in the water to be treated A can be separated by phase separation. The separated inorganic salts and / or organic matter can also be recovered. The inorganic salts are dissolved in the water to be treated A and exist as ions in the water to be treated A. When the organic matter is a water-soluble salt, the water to be treated A contains ionized organic matter and counterions of the ionized organic matter. The organic matter contained in the water to be treated A (organic matter recovered by precipitation) is preferably a water-soluble compound that is solid or liquid at the treatment temperature. The water to be treated A can be treated even if it contains substantially no salts and only organic matter. When "water to be treated A" is written alone, it refers to the water to be treated A before the water treatment of the embodiment.

[0016] The water to be treated A is an aqueous solution. The total mass of the inorganic salts and / or organic substances and the water is preferably 5 wt% to 300 wt% of the water in the water to be treated A. In addition to the inorganic salts and / or organic substances and water, the water to be treated A may contain 0.0 wt% to 5 wt% of one or more selected from the group consisting of water-insoluble organic substances, water-soluble organic substances that are liquid at the treatment temperature, metals, and metal oxides.

[0017] There are no particular limitations on the concentration of inorganic salts and / or organic matter contained in the water to be treated A. In the embodiment, the inorganic salts and / or organic matter can be separated regardless of the concentration of inorganic salts and / or organic matter contained in the water to be treated A.

[0018] Specifically, the ions contained in the water to be treated A are preferably one or more selected from the group consisting of sodium ions, potassium ions, lithium ions, magnesium ions, calcium ions, manganese ions, iron ions, fluoride ions, sulfate ions, nitrate ions, nitrite ions, chloride ions, bromide ions, iodide ions, cyanide ions, acetate ions, bicarbonate ions, thiocyanate ions, hydrogen sulfide ions, hydrogen oxalate ions, chlorate ions, perchlorate ions, hypochlorite ions, hydroxide ions, silver ions, copper ions, iron ions, cobalt ions, tin ions, lead ions, manganese ions, ammonium ions, aluminum ions, chromium ions, various complex ions, phosphate ions, strontium ions, barium ions, cadmium ions, nickel ions, zinc ions, mercury ions, ionic silica, etc. The water to be treated A may also contain non-ionized organic matter, silica, and colloidal silica.

[0019] The first container B is a container for containing the water to be treated A and the amine solution. The first container B is preferably provided with a means 11 for introducing the water to be treated A into the first container B, a means 12 for introducing the amine solution C into the first container B to obtain a first mixture D, a temperature control means 13, and a means 14 for separating the supernatant phase F and the concentrated phase G. The means 14 for separating the supernatant phase F and the concentrated phase G may also be provided in a container separate from the first container B.

[0020] The total pressure in the first container B is preferably 700 Pa or more and 1 MPa or less. The gas in the first container B includes carbon dioxide, argon, oxygen, nitrogen, etc. A portion of the gas contained in the first container B is contained in one or more selected from the group consisting of the water to be treated A, the amine solution C, the first mixture D, the second mixture E, and the supernatant phase F.

[0021] The means 12 for introducing the amine solution C into the first container B to obtain a first mixture D introduces the amine solution C into the first container B. The means 12 for introducing the amine solution C into the first container B to obtain a first mixture D includes, for example, a pipe leading to the first container B, and instruments for determining the properties of the amine solution C, such as a pH meter, a conductivity meter, and a thermometer, as well as a valve, a cock, a pump, and the like for controlling the flow rate of the amine solution C flowing through the pipe.

[0022] The temperature adjustment means 13 can adjust the temperatures of the water to be treated A, the first container B, the amine solution C, the first mixture D, the phase-separated second mixture E, the supernatant phase F, and the concentrated phase G. Temperature adjustment by the temperature adjustment means 13 is not performed when it is not necessary. As the temperature adjustment means 13, a heat medium such as a heater or hot water and / or a refrigerant such as a cooling coil or the atmosphere (air cooling) is used. It is preferable to use exhaust heat as the temperature adjustment means 13.

[0023] Whether or not the temperature control means 13 is used, the temperature of the first mixture D in the first container B is preferably 3°C or higher and 40°C or lower. If the temperature of the first mixture D is too low, a lot of energy is required for cooling, and the viscosity of the solution increases, making it difficult to handle. If the temperature of the first mixture D is high, a lot of energy is required for heating, the amine compound may volatilize, and it may be difficult to form each phase. The temperature of the first mixture D is more preferably 5°C or higher and 35°C or lower. By maintaining the first mixture D and the phase-separated second mixture E at the above low temperatures, the concentrated phase G can be recovered.

[0024] Amine solution C contains an amine compound whose solubility changes in response to temperature. The liquid properties of a solution containing amine solution C change depending on the temperature in the solution. By mixing amine solution C with water to be treated A at a low temperature, the solutes contained in water to be treated A precipitate, or the water containing the solutes contained in water to be treated A undergoes phase separation from the amine.

[0025] The amine compound used in the embodiment is liquid at room temperature.

[0026] When the amine compound used in the embodiments is mixed with water, it forms a homogeneous phase with water or undergoes phase separation into an aqueous phase and an organic phase, depending on the temperature. In the first embodiment, water treatment is performed by utilizing the property of the amine compound used, which easily absorbs water at low temperatures. In the second and subsequent embodiments, reuse of the amine compound is described by utilizing the property of phase separation into an aqueous phase and an organic phase at high temperatures. Compounds with low boiling points emit a distinctive ammonia odor, so compounds with high boiling points are more preferable. Furthermore, phase separation properties vary depending on the compound, and some are soluble in water to a certain extent even at high temperatures. Using amines that are easily soluble in water increases the amount of amine contained in the supernatant phase F, so compounds with high phase separation properties that are less soluble in water at high temperatures are more preferable. Using amine compounds with high solubility at room temperature, a high boiling point, and high phase separation properties when heated enables efficient separation. Furthermore, amine compounds that allow efficient precipitation operations with a small amount of amine compound are preferred.

[0027] Figures 3 and 4 show the chemical formulas of amine compounds according to embodiments. Amine solution C preferably contains an amine compound represented by chemical formula (1) and / or (2) shown in Figures 3 and 4. Amine solution C preferably contains an amine compound represented by chemical formula (1) or (2) shown in Figures 3 and 4. Amine solution C preferably contains an amine compound represented by chemical formula (1) and (2) shown in Figures 3 and 4. Hereinafter, the amine compound represented by chemical formula (1) or (2) may be referred to as the amine compound according to embodiments. The amine compound according to embodiments has high compatibility with water at low temperatures. Due to its high compatibility with water, many amine compounds according to embodiments dissolve in water. When the amine compound according to embodiments is dissolved in water at a volume of 2 to 7 times or more, substances that were dissolved in the water to be treated A become less soluble in the water to be treated. The substances that are no longer soluble in the water to be treated A become concentrated phase G. The compatibility of the amine compound according to embodiments with water decreases when heated. The concentrated phase G in the second mixture E is maintained at a low temperature. The state in which the solution is separated into a concentrated phase G and a supernatant phase F is maintained at a low temperature. In the embodiment, the supernatant phase F undergoes phase separation when heated. When heated, the solution containing the amine compound of the embodiment exceeds the lower critical solution temperature of the amine compound, thereby changing the liquid properties. In the first embodiment, the high compatibility with water at low temperatures of the amine compound of the first embodiment is utilized.

[0028] The amine compound of the embodiment has a high dissolution rate in water, and therefore, the concentrated phase G appears quickly. The rapid appearance of the concentrated phase G improves the efficiency of the water treatment. The amine compound of the embodiment has a high vapor pressure at 25°C, and therefore does not easily volatilize during the water treatment.

[0029] The amine compound of the embodiment appears in a relatively small amount to produce concentrated phase G. This means that a small amount of the amine compound of the embodiment may be required to produce concentrated phase G. It is preferable that the use of the amine compound of the embodiment results in high utilization efficiency of the amine compound used to produce concentrated phase G.

[0030] The vapor pressure of the amine compounds of the embodiment (the amine compounds of chemical formula (1) and the amine compounds of chemical formula (2)) at 25°C under the atmosphere (air of 1 bar (760 Torr)) is 1.0 × 10 -10 [Torr] or more and 5.0 [Torr] or less are preferable, and 1.0 × 10 -10 [Torr] or more and 3.0 [Torr] or less are more preferable, and 1.0 × 10 -10 It is more preferable that the pressure is not less than 1.0 Torr and not more than 1.0 Torr.

[0031] When water treatment was carried out at 10° C., the amine compound of the embodiment was confirmed to have high solubility in the water to be treated A and to produce a concentrated phase G.

[0032] From the viewpoint of high solubility at room temperature, high boiling point, and high phase separation property when heated, R 1 is preferably a linear alkyl chain having 2 to 6 carbon atoms, a branched alkyl chain having 4 to 6 carbon atoms, a cyclic alkyl chain having 5 or 6 carbon atoms, an ether chain having 2 to 6 carbon atoms, or an aminoalkyl chain having 2 to 9 carbon atoms. 2 is preferably a hydrocarbon group having 1 to 6 carbon atoms. 3 is preferably a hydrocarbon group having a carbon number of 1 to 6. From the same viewpoint, in chemical formula (1), [number of carbon atoms in the molecule] / [number of nitrogen atoms in the molecule] is preferably 4.0 or more and 7.0 or less.

[0033] From the viewpoint of high solubility at room temperature, high boiling point, and high phase separation property at elevated temperature, R 4 is preferably a linear alkyl chain having 2 to 6 carbon atoms, a branched alkyl chain having 4 to 6 carbon atoms, a cyclic alkyl chain having 5 or 6 carbon atoms, an ether chain having 2 to 6 carbon atoms, or an aminoalkyl chain having 2 to 9 carbon atoms. 5 is preferably a hydrocarbon group having 1 to 6 carbon atoms. 6 is preferably a hydrocarbon group having 1 to 6 carbon atoms.7 is preferably a hydrocarbon group having a carbon number of 1 to 6. From the same viewpoint, in chemical formula (2), [number of carbon atoms in the molecule] / [number of nitrogen atoms in the molecule] is preferably 4.0 or more and 7.0 or less.

[0034] From the viewpoint of high solubility at room temperature, high boiling point, and high phase separation property when heated, R 1 is preferably a linear alkyl chain having 2 to 6 carbon atoms, a branched alkyl chain having 4 to 6 carbon atoms, a cyclic alkyl chain having 5 or 6 carbon atoms, an ether chain having 2 to 6 carbon atoms, or an aminoalkyl chain having 2 to 9 carbon atoms. 2 is preferably a hydrocarbon group having 1 to 6 carbon atoms and optionally containing nitrogen. 3 is preferably a hydrocarbon group having 1 to 6 carbon atoms and optionally containing nitrogen. From this viewpoint, in chemical formula (1), the ratio [number of carbon atoms in the molecule] / [number of nitrogen atoms in the molecule] is preferably 4.0 or more and 7.0 or less. When the hydrocarbon group contains nitrogen, the hydrocarbon group is preferably a secondary or tertiary amino group.

[0035] From the viewpoint of high solubility at room temperature, high boiling point, and high phase separation property at elevated temperature, R 4 is preferably a linear alkyl chain having 2 to 6 carbon atoms, a branched alkyl chain having 4 to 6 carbon atoms, a cyclic alkyl chain having 5 or 6 carbon atoms, an ether chain having 2 to 6 carbon atoms, or an aminoalkyl chain having 2 to 9 carbon atoms. 5 is preferably a hydrocarbon group having 1 to 6 carbon atoms and optionally containing nitrogen. 6 is preferably a hydrocarbon group having 1 to 6 carbon atoms. 7 is preferably a hydrocarbon group having 1 to 6 carbon atoms. From the same viewpoint, in chemical formula (2), [number of carbon atoms in the molecule] / [number of nitrogen atoms in the molecule] is preferably 4.0 or more and 7.0 or less. When the hydrocarbon group contains nitrogen, the hydrocarbon group is preferably a secondary or tertiary amino group.

[0036] From the viewpoint of high solubility at room temperature, high boiling point, and high phase separation property when heated, R 1 is a linear alkyl chain having 2 to 6 carbon atoms, a branched alkyl chain having 4 to 6 carbon atoms, or a cyclic alkyl chain having 5 or 6 carbon atoms, and the cyclic alkyl chain is unsubstituted and the first carbon atom of the cyclic alkyl chain is R 2 The carbon atom at the 2nd position of the cyclic alkyl chain is bonded to the nitrogen atom bonded to R 3 Preferably, the R bonded to the nitrogen atom is a cyclic alkyl chain, a linear ether chain having 2 to 6 carbon atoms, or a linear aminoalkyl chain having 2 to 9 carbon atoms. 2 is preferably a hydrocarbon group having 1 to 6 carbon atoms and consisting of carbon and hydrogen, or a hydrocarbon group having 1 to 6 carbon atoms and consisting of carbon, hydrogen, and oxygen. 3 is preferably a hydrocarbon group having 1 to 6 carbon atoms and consisting of carbon and hydrogen, or a hydrocarbon group having 1 to 6 carbon atoms and consisting of carbon, hydrogen, and oxygen. From this viewpoint, in chemical formula (1), [number of carbon atoms in molecule] / [number of nitrogen atoms in molecule] is preferably 4.0 or more and 7.0 or less.

[0037] From the viewpoint of high solubility at room temperature, high boiling point, and high phase separation property at elevated temperature, R 4 is a linear alkyl chain having 2 to 6 carbon atoms, a branched alkyl chain having 4 to 6 carbon atoms, or a cyclic alkyl chain having 5 or 6 carbon atoms, and the cyclic alkyl chain is unsubstituted and the first carbon atom of the cyclic alkyl chain is R 2 The carbon atom at the 2nd position of the cyclic alkyl chain is bonded to the nitrogen atom bonded to R 3 The nitrogen bonded to R is preferably a cyclic alkyl chain, a cyclic alkyl chain having 5 or 6 carbon atoms, a linear ether chain having 2 to 6 carbon atoms, or a linear aminoalkyl chain having 2 to 9 carbon atoms. 5 is preferably a hydrocarbon group having 1 to 6 carbon atoms and consisting of carbon and hydrogen, or a hydrocarbon group having 1 to 6 carbon atoms and consisting of carbon, hydrogen, and oxygen. 6is preferably a hydrocarbon group having 1 to 6 carbon atoms and consisting of carbon and hydrogen, or a hydrocarbon group having 1 to 6 carbon atoms and consisting of carbon, hydrogen, and oxygen. 7 is preferably a hydrocarbon group having 1 to 6 carbon atoms and consisting of carbon and hydrogen, or a hydrocarbon group having 1 to 6 carbon atoms and consisting of carbon, hydrogen, and oxygen. From the same viewpoint, in chemical formula (2), [number of carbon atoms in the molecule] / [number of nitrogen atoms in the molecule] is preferably 4.0 or more and 7.0 or less.

[0038] From the viewpoint of high solubility at room temperature, high boiling point, and high phase separation property when heated, R 1 is a linear alkyl chain having 2 to 6 carbon atoms, a branched alkyl chain having 4 to 6 carbon atoms, or a cyclic alkyl chain having 5 or 6 carbon atoms, and the cyclic alkyl chain is unsubstituted and the first carbon atom of the cyclic alkyl chain is R 2 The carbon atom at the 2nd position of the cyclic alkyl chain is bonded to the nitrogen atom bonded to R 3 and a linear ether chain having 2 to 6 carbon atoms and an ether chain having an alkyl chain having 2 or 3 carbon atoms bonded to oxygen, or a linear aminoalkyl chain having 2 to 9 carbon atoms, in which the amino group contained in the aminoalkyl chain is secondary, the number of amino groups contained in the aminoalkyl chain is 1 to 3, and the linear alkyl chain having 2 or 3 carbon atoms is bonded to the amino group of the aminoalkyl chain. From this viewpoint, the R of chemical formula (1) is preferably an aminoalkyl chain. 2 is preferably a saturated hydrocarbon group having 1 to 6 carbon atoms and consisting of carbon and hydrogen, or a saturated hydrocarbon group having 1 to 6 carbon atoms and consisting of carbon, hydrogen, and oxygen. 3 is preferably a saturated hydrocarbon group having 1 to 6 carbon atoms and consisting of carbon and hydrogen, or a saturated hydrocarbon group having 1 to 6 carbon atoms and consisting of carbon, hydrogen, and oxygen. From this viewpoint, in chemical formula (1), [number of carbon atoms in molecule] / [number of nitrogen atoms in molecule] is preferably 4.0 or more and 7.0 or less.

[0039] From the viewpoint of high solubility at room temperature, high boiling point, and high phase separation property at elevated temperature, R 4is a linear alkyl chain having 2 to 6 carbon atoms, a branched alkyl chain having 4 to 6 carbon atoms, or a cyclic alkyl chain having 5 or 6 carbon atoms, and the cyclic alkyl chain is unsubstituted and the first carbon atom of the cyclic alkyl chain is R 2 The carbon atom at the 2nd position of the cyclic alkyl chain is bonded to the nitrogen atom bonded to R 3 From the same viewpoint, the preferred aminoalkyl chains are those in which the R of chemical formula (2) is a cyclic alkyl chain bonded to a nitrogen atom bonded to the R of the formula (2), a cyclic alkyl chain having 5 or 6 carbon atoms, a linear ether chain having 2 to 6 carbon atoms, and an alkyl chain having 2 or 3 carbon atoms bonded to the oxygen atom, or a linear aminoalkyl chain having 2 to 9 carbon atoms, in which the amino group contained in the aminoalkyl chain is secondary, the number of amino groups contained in the aminoalkyl chain is 1 to 3, and the linear alkyl chain having 2 or 3 carbon atoms is bonded to the amino group of the aminoalkyl chain. 5 is preferably a saturated hydrocarbon group having 1 to 6 carbon atoms and consisting of carbon and hydrogen, or a saturated hydrocarbon group having 1 to 6 carbon atoms and consisting of carbon, hydrogen, and oxygen. 6 is preferably a saturated hydrocarbon group having 1 to 6 carbon atoms and consisting of carbon and hydrogen, or a saturated hydrocarbon group having 1 to 6 carbon atoms and consisting of carbon, hydrogen, and oxygen. 7 is preferably a saturated hydrocarbon group having 1 to 6 carbon atoms and consisting of carbon and hydrogen, or a saturated hydrocarbon group having 1 to 6 carbon atoms and consisting of carbon, hydrogen, and oxygen. From this viewpoint, in chemical formula (2), [number of carbon atoms in molecule] / [number of nitrogen atoms in molecule] is preferably 4.0 or more and 7.0 or less.

[0040] From the viewpoint of high solubility at room temperature, high boiling point, and high phase separation property when heated, R 1 is a linear alkyl chain having 2 to 6 carbon atoms, a branched alkyl chain having 4 to 6 carbon atoms, or a cyclic alkyl chain having 5 or 6 carbon atoms, and the cyclic alkyl chain is unsubstituted and the first carbon atom of the cyclic alkyl chain is R 2 The carbon atom at the 2nd position of the cyclic alkyl chain is bonded to the nitrogen atom bonded to R 3From this viewpoint, it is preferable that the R of chemical formula (1) is a cyclic alkyl chain bonded to a nitrogen atom bonded to the R, a linear ether chain having 2 to 6 carbon atoms, an ether chain having an alkyl chain having 2 or 3 carbon atoms bonded to oxygen, or a linear aminoalkyl chain having 2 to 9 carbon atoms, in which the amino group contained in the aminoalkyl chain is secondary, the number of amino groups contained in the aminoalkyl chain is 1 to 3, and the linear alkyl chain having 2 or 3 carbon atoms is bonded to the amino group of the aminoalkyl chain. 2 is preferably a saturated hydrocarbon group having 1 to 6 carbon atoms and consisting of carbon and hydrogen. 3 is preferably a saturated hydrocarbon group having 1 to 6 carbon atoms and consisting of carbon and hydrogen, or an ether group or alcohol group having 1 to 6 carbon atoms and consisting of carbon, hydrogen, and oxygen. From this viewpoint, in chemical formula (1), [number of carbon atoms in the molecule] / [number of nitrogen atoms in the molecule] is preferably 4.0 or more and 7.0 or less.

[0041] From the viewpoint of high solubility at room temperature, high boiling point, and high phase separation property at elevated temperature, R 4 is preferably a linear alkyl chain having 2 to 6 carbon atoms, a branched alkyl chain having 4 to 6 carbon atoms, a cyclic alkyl chain having 5 or 6 carbon atoms, the cyclic alkyl chain being unsubstituted and having the carbon atom at position 1 bonded to the nitrogen bonded to R2 and the carbon atom at position 2 bonded to the nitrogen bonded to R3, a cyclic alkyl chain having 5 or 6 carbon atoms, a linear ether chain having 2 to 6 carbon atoms, an alkyl chain having 2 or 3 carbon atoms bonded to the oxygen atom, or a linear amino alkyl chain having 2 to 9 carbon atoms, the amino group contained in the amino alkyl chain being secondary, the number of amino groups contained in the amino alkyl chain being 1 to 3, and the linear alkyl chain having 2 or 3 carbon atoms bonded to the amino group of the amino alkyl chain. From the same viewpoint, R in chemical formula (2) is preferably an amino alkyl chain having 2 to 6 carbon atoms, a linear ether chain having 2 to 6 carbon atoms, an alkyl chain having 2 or 3 carbon atoms bonded to the amino group of the amino alkyl chain. 5 is preferably a saturated hydrocarbon group having 1 to 6 carbon atoms and consisting of carbon and hydrogen, or an ether group or alcohol group having 1 to 6 carbon atoms and consisting of carbon, hydrogen, and oxygen. 6is preferably a saturated hydrocarbon group having 1 to 6 carbon atoms and consisting of carbon and hydrogen, or an ether group or alcohol group having 1 to 6 carbon atoms and consisting of carbon, hydrogen, and oxygen. 7 is preferably a saturated hydrocarbon group having 1 to 6 carbon atoms and consisting of carbon and hydrogen. From the same viewpoint, in chemical formula (2), [number of carbon atoms in the molecule] / [number of nitrogen atoms in the molecule] is preferably 4.0 or more and 7.0 or less.

[0042] From the viewpoint of high solubility at room temperature, high boiling point, and high phase separation property at elevated temperature, R 4 is preferably a linear alkyl chain having 2 to 6 carbon atoms, a branched alkyl chain having 4 to 6 carbon atoms, a cyclic alkyl chain having 5 or 6 carbon atoms, the cyclic alkyl chain being unsubstituted and having the carbon atom at position 1 bonded to the nitrogen bonded to R2 and the carbon atom at position 2 bonded to the nitrogen bonded to R3, a cyclic alkyl chain having 5 or 6 carbon atoms, a linear ether chain having 2 to 6 carbon atoms, an alkyl chain having 2 or 3 carbon atoms bonded to the oxygen atom, or a linear amino alkyl chain having 2 to 9 carbon atoms, the amino group contained in the amino alkyl chain being secondary, the number of amino groups contained in the amino alkyl chain being 1 to 3, and the linear alkyl chain having 2 or 3 carbon atoms bonded to the amino group of the amino alkyl chain. From the same viewpoint, R in chemical formula (2) is preferably an amino alkyl chain having 2 to 6 carbon atoms, a linear ether chain having 2 to 6 carbon atoms, an alkyl chain having 2 or 3 carbon atoms bonded to the amino group of the amino alkyl chain. 5 is preferably a saturated hydrocarbon group having 1 to 6 carbon atoms and consisting of carbon and hydrogen, or an ether group or alcohol group having 1 to 6 carbon atoms and consisting of carbon, hydrogen, and oxygen. 6 is preferably a saturated hydrocarbon group having 1 to 3 carbon atoms and consisting of carbon and hydrogen, or an ether group or alcohol group having 1 to 3 carbon atoms and consisting of carbon, hydrogen, and oxygen. 7 is preferably a saturated hydrocarbon group consisting of carbon and hydrogen and having 1 to 3 carbon atoms. From this viewpoint, in chemical formula (2), [number of carbon atoms in the molecule] / [number of nitrogen atoms in the molecule] is preferably 4.0 or more and 7.0 or less.

[0043] From the viewpoint of high solubility at room temperature, high boiling point, and high phase separation property at elevated temperature, R 4 is preferably a linear alkyl chain having 2 to 6 carbon atoms, a branched alkyl chain having 4 to 6 carbon atoms, a cyclic alkyl chain having 5 or 6 carbon atoms, the cyclic alkyl chain being unsubstituted and having the carbon atom at position 1 bonded to the nitrogen bonded to R2 and the carbon atom at position 2 bonded to the nitrogen bonded to R3, a cyclic alkyl chain having 5 or 6 carbon atoms, a linear ether chain having 2 to 6 carbon atoms, an alkyl chain having 2 or 3 carbon atoms bonded to the oxygen atom, or a linear amino alkyl chain having 2 to 9 carbon atoms, the amino group contained in the amino alkyl chain being secondary, the number of amino groups contained in the amino alkyl chain being 1 to 3, and the linear alkyl chain having 2 or 3 carbon atoms bonded to the amino group of the amino alkyl chain. From the same viewpoint, R in chemical formula (2) is preferably an amino alkyl chain having 2 to 6 carbon atoms, a linear ether chain having 2 to 6 carbon atoms, an alkyl chain having 2 or 3 carbon atoms bonded to the amino group of the amino alkyl chain. 5 is preferably a saturated hydrocarbon group having 1 to 6 carbon atoms and consisting of carbon and hydrogen, or an ether group or alcohol group having 1 to 6 carbon atoms and consisting of carbon, hydrogen, and oxygen. 6 is preferably a saturated hydrocarbon group having 1 or 2 carbon atoms and consisting of carbon and hydrogen, or an ether group or alcohol group having 1 to 3 carbon atoms and consisting of carbon, hydrogen, and oxygen. 7 is preferably a saturated hydrocarbon group having 1 or 2 carbon atoms and consisting of carbon and hydrogen. From the same viewpoint, in chemical formula (2), [number of carbon atoms in the molecule] / [number of nitrogen atoms in the molecule] is preferably 4.0 or more and 7.0 or less.

[0044] In the following, R in chemical formula (1) 1 The hyphen on the left side of the symbol represents the chemical bond that connects the nitrogen atom on the left side of the formula (1), and R 1 The hyphen on the right side of the formula (1) may represent a chemical bond to the nitrogen on the right side of the formula (1). 2 The hyphen in the formula (1) may represent a chemical bond to the nitrogen on the left side. 3 The hyphen in the formula (1) may represent a chemical bond to the nitrogen on the right side of the formula (1). 2 and R3 The methyl group is sometimes represented as Me, the ethyl group as Et, and the n-propyl group as Pr. 1 , R 2 and R 3 The branched alkyl chains are enclosed in parentheses.

[0045] In the following, R in chemical formula (2) 4 The hyphen on the left side of the formula (2) represents the chemical bond that connects to the nitrogen on the left side of the formula (2), and R 4 The hyphen on the right side of the formula (2) may represent a chemical bond to the nitrogen on the right side of the formula (2). 5 The hyphen on the right side of the formula (2) may represent a chemical bond to the nitrogen on the left side of the formula (2). 6 The hyphen in the formula (2) may represent a chemical bond to the nitrogen on the right side. 7 The hyphen in the formula (2) may represent a chemical bond to the nitrogen on the right side of the formula. 5 , R 6 and R 7 The methyl group is sometimes represented as Me, the ethyl group as Et, and the isopropyl group as Pr.

[0046] R in chemical formula (1) 1 -CH2CH2-, -CH2CH2CH2-, -CH2CH2CH2CH2-, -CH2CH2CH2CH2CH2-, -CH2CH2CH2CH2CH2CH2-, -(CH2CH2NH) n -(CH2CH2) m -(n is 1 to 3, m is 1), -(CH2CH2CH2NH) p -(CH2CH2CH2) q -(p is 1 or 2, q is 1), -CH2CH2CH2OCH2CH2CH2-, -CH2CH2OCH2CH2-, -CH2CH(Me)CH2-, -CH2C(Me)2CH2-, -C(Me)2C(Me)2-, or -(CH4)- (cyclic alkyl chain) is preferred. 2 -Me, -Et, -Pr, -CH(Me)Me, -CH(Et)Et, -CH(Me)Et, -CH(Et)Pr, -C6H 11(cyclohexyl group), -C5H9 (cyclopentyl group), -CH(Me)CH2CH2OMe, -CH2CH2OMe, -CH2CH2OEt, -CH2CH2OPr, -CH2CH2CH2OH, -CH2CH2CH2OMe, -CH2CH2CH2OEt, -CH2CH2CH2OPr, or -CH2CH2OH is preferred. 3 -Me, -Et, -Pr, -CH(Me)Me, -CH(Et)Et, -CH(Me)Et, -CH(Et)Pr, -C6H 11 (cyclohexyl group), -C5H9 (cyclopentyl group), -CH(Me)CH2CHOMe, -CH2CHOMe, -CH2CHOEt, -CH2CH2OPr, -CH2CH2CH2OH, -CH2CH2CH2OMe, -CH2CH2CH2OEt, -CH2CH2CH2OPr, or -CH2CH2OH is preferred. In chemical formula (1), R is selected so as to satisfy the range of [number of carbon atoms in molecule] / [number of nitrogen atoms in molecule]. 1 , R 2 and R 3 By using an amine compound selected from the above, suitable water treatment can be carried out.

[0047] R in chemical formula (2) 4 -CH2CH2-, -CH2CH2CH2-, -CH2CH2CH2CH2-, -CH2CH2CH2CH2CH2-, -CH2CH2CH2CH2CH2CH2-, -(CH2CH2NH) s -(CH2CH2) t -(s is 1 to 3, t is 1), -(CH2CH2CH2NH) x -(CH2CH2CH2) y -(x is 1 or 2, y is 1), -CH2CH2CH2OCH2CH2CH2-, -CH2CH2OCH2CH2-, -CH2CH(Me)CH2-, -CH2C(Me)2CH2-, -C(Me)2C(Me)2-, or -(CH4)- (cyclic alkyl chain) is preferred. 5 -Me, -Et, -Pr, -CH(Me)Me, -CH(Et)Et, -CH(Me)Et, -C6H 11(cyclohexyl group), -C5H9 (cyclopentyl group), -CH(Me)CH2CH2OMe, -CH2CH2OMe, -CH2CH2OEt, -CH2CH2OPr, -CH2CH2CH2OH, -CH2CH2CH2OMe, -CH2CH2CH2OEt, -CH2CH2CH2OPr, or -CH2CH2OH is preferred. 6 -Me, -Et, -Pr, -CH(Me)Me, -CH(Et)Et, -CH(Me)Et, -CH(Et)Pr, -C6H 11 (cyclohexyl group), -C5H9 (cyclopentyl group), -CH(Me)CH2CH2OMe, -CH2CH2OMe, -CH2CH2OEt, -CH2CH2OPr, -CH2CH2CH2OH, -CH2CH2CH2OMe, -CH2CH2CH2OEt, -CH2CH2CH2OPr, or -CH2CH2OH is preferred. 7 In the chemical formula (2), R is preferably -Me, -Et, or -Pr so as to satisfy the range of [number of carbon atoms in the molecule] / [number of nitrogen atoms in the molecule]. 4 , R 5 , R 6 and R 7 By using an amine compound selected from the above, suitable water treatment can be carried out.

[0048] R in chemical formula (1) 1 is preferably -CH2CH2-, -CH2CH2CH2-, -CH2CH2CH2CH2-, -CH2CH2CH2CH2CH2-, or -CH2CH2CH2CH2CH2CH2-. 2 -Me, -Et, -CH(Me)Me, -CH(Et)Et, -CH(Me)Et, -CH(Et)Pr, -C6H 11 (cyclohexyl group), or —C5H9 (cyclopentyl group). 3 -Me, -Et, -CH(Me)Me, -CH(Et)Et, -CH(Me)Et, -CH(Et)Pr, -C6H 11In the chemical formula (1), R is preferably selected so as to satisfy the range of [number of carbon atoms in the molecule] / [number of nitrogen atoms in the molecule]. 1 , R 2 and R 3 By using an amine compound selected from the above, suitable water treatment can be carried out.

[0049] R in chemical formula (2) 4 is preferably -CH2CH2-, -CH2CH2CH2-, -CH2CH2CH2CH2-, -CH2CH2CH2CH2CH2-, or -CH2CH2CH2CH2CH2CH2-. 5 -Me, -Et, -CH(Me)Me, -CH(Et)Et, -CH(Me)Et, -CH(Et)Pr, -C6H 11 (cyclohexyl group), or —C5H9 (cyclopentyl group). 6 -Me, -Et, -CH(Me)Me, -CH(Et)Et, -CH(Me)Et, -CH(Et)Pr, -C6H 11 (cyclohexyl group), or —C5H9 (cyclopentyl group). 7 In the chemical formula (2), R is preferably -Me or -Et so as to satisfy the range of [number of carbon atoms in the molecule] / [number of nitrogen atoms in the molecule]. 4 , R 5 , R 6 and R 7 By using an amine compound selected from the above, suitable water treatment can be carried out.

[0050] R in chemical formula (1) 1 is preferably -CH2CH2-, -CH2CH2CH2-, -CH2CH2CH2CH2-, -CH2CH2CH2CH2CH2-, or -CH2CH2CH2CH2CH2CH2-. 2 is preferably -Me, -Et, -CH(Me)Me, -CH(Et)Et, -CH(Me)Et, or -CH(Et)Pr. 3In chemical formula (1), R is preferably -CH(Me)Me, -CH(Et)Et, -CH(Me)Et, or -CH(Et)Pr so as to satisfy the range of [number of carbon atoms in molecule] / [number of nitrogen atoms in molecule]. 1 , R 2 and R 3 By using an amine compound selected from the above, suitable water treatment can be carried out.

[0051] R in chemical formula (2) 4 is preferably -CH2CH2-, -CH2CH2CH2-, -CH2CH2CH2CH2-, -CH2CH2CH2CH2CH2-, or -CH2CH2CH2CH2CH2CH2-. 5 is preferably -Me, -Et, -CH(Me)Me, -CH(Et)Et, -CH(Me)Et, or -CH(Et)Pr. 6 is preferably -Me, -Et, -CH(Me)Me, -CH(Et)Et, -CH(Me)Et, or -CH(Et)Pr. 7 In the chemical formula (2), R is preferably -Me or -Et so as to satisfy the range of [number of carbon atoms in the molecule] / [number of nitrogen atoms in the molecule]. 4 , R 5 , R 6 and R 7 By using an amine compound selected from the above, suitable water treatment can be carried out.

[0052] R in chemical formula (2) 4 is preferably -CH2CH2-, -CH2CH2CH2-, -CH2CH2CH2CH2-, -CH2CH2CH2CH2CH2-, or -CH2CH2CH2CH2CH2CH2-. 5 is preferably -Me, -Et, -CH(Me)Me, -CH(Et)Et, -CH(Me)Et, or -CH(Et)Pr. 6 is preferably -Me, -Et or -CH(Me)Me. 7In the chemical formula (2), R is preferably -Me or -Et so as to satisfy the range of [number of carbon atoms in the molecule] / [number of nitrogen atoms in the molecule]. 4 , R 5 , R 6 and R 7 By using an amine compound selected from the above, suitable water treatment can be carried out.

[0053] R in chemical formula (1) 1 is preferably -CH2CH2- or -CH2CH2CH2-. 2 is preferably -Me, -Et, -CH(Me)Me, -CH(Et)Et, -CH(Me)Et, or -CH(Et)Pr. 3 In chemical formula (1), R is preferably -CH(Me)Me, -CH(Et)Et, -CH(Me)Et, or -CH(Et)Pr so as to satisfy the range of [number of carbon atoms in molecule] / [number of nitrogen atoms in molecule]. 1 , R 2 and R 3 By using an amine compound selected from the above, suitable water treatment can be carried out.

[0054] R in chemical formula (2) 4 is preferably -CH2CH2- or -CH2CH2CH2-. 5 is preferably -Me, -Et, -CH(Me)Me, -CH(Et)Et, -CH(Me)Et, or -CH(Et)Pr. 6 is preferably -Me, -Et, -CH(Me)Me, -CH(Et)Et, -CH(Me)Et, or -CH(Et)Pr. 7 In the chemical formula (2), R is preferably -Me or -Et so as to satisfy the range of [number of carbon atoms in the molecule] / [number of nitrogen atoms in the molecule]. 4 , R 5 , R 6 and R 7 By using an amine compound selected from the above, suitable water treatment can be carried out.

[0055] R of the amine compound of the above chemical formula (1) 2 and R 3 and / or R of the amine compound of the above chemical formula (1) 2 and R 3 It is preferable to use amine compounds having different structures in the water treatment of the embodiment.

[0056] R of the amine compound of the above chemical formula (2) 6 and R 7 and / or R of the amine compound of the above chemical formula (2) 6 and R 7 In the water treatment of the embodiment, it is preferable to use an amine compound having different R 5 , R 6 and R 7 It is preferable to use an amine compound in which two or three of the R of the amine compound represented by the above chemical formula (2) are the same for the water treatment of the embodiment. 5 , R 6 and R 7 In the water treatment of the embodiment, it is preferable to use an amine compound in which all of the R of the amine compound represented by the above chemical formula (2) are different. 5 R 6 and / or R 7 It is preferable to use an amine compound different from the above in the water treatment of the embodiment.

[0057] From the viewpoint of high solubility at room temperature, high boiling point, high phase separation property upon heating, and cost, R 1 The linear alkyl chain preferably has 2 or 3 carbon atoms.

[0058] From the viewpoint of high solubility at room temperature, high boiling point, high phase separation property upon heating, and cost, R 4 The linear alkyl chain preferably has 2 or 3 carbon atoms.

[0059] R is a compound with high solubility at room temperature, high boiling point, and high phase separation when heated. 6 and / or R 7 The carbon number of 1 to 3 is preferably

[0060] In view of high solubility at room temperature, a high boiling point, and high phase separation upon heating, the number of nitrogen atoms contained in the molecule of chemical formula (1) is preferably 2 or more and 5 or less, more preferably 2 or more and 4 or less, even more preferably 2 or more and 3 or less, and even more preferably 2.

[0061] From the viewpoints of high solubility at room temperature, high boiling point, and high phase separation property upon heating, the number of nitrogen atoms contained in the molecule of chemical formula (2) is preferably 2 or more and 5 or less, more preferably 2 or more and 4 or less, even more preferably 2 or more and 3 or less, and even more preferably 2.

[0062] In chemical formula (1), the ratio of [number of carbon atoms in the molecule] / [number of nitrogen atoms in the molecule] is more preferably 4.0 or more and 6.0 or less, and even more preferably 4.5 or more and 6.0 or less.

[0063] In chemical formula (2), the ratio of [number of carbon atoms in the molecule] / [number of nitrogen atoms in the molecule] is more preferably 4.0 or more and 6.0 or less, and even more preferably 4.5 or more and 6.0 or less.

[0064] Amine solution C preferably contains 80 wt% or more and 100 wt% or less of an amine compound whose solubility changes in response to heat, more preferably 90 wt% or more and 100 wt% or less, and more preferably 95 wt% or more and 100 wt% or less.

[0065] Amine solution C preferably contains 80 wt% or more and 100 wt% or less of the amine compounds of chemical formula (1) and / or chemical formula (2), more preferably 90 wt% or more and 100 wt% or less, and more preferably 95 wt% or more and 100 wt% or less.

[0066] Amine solution C preferably contains 80 wt% or more and 100 wt% or less of the amine compound of chemical formula (1) or chemical formula (2), more preferably 90 wt% or more and 100 wt% or less, and more preferably 95 wt% or more and 100 wt% or less.

[0067] The amine compound of the embodiment preferably has high solubility in water. Because the amine compound of the embodiment has high solubility, the time required for phase separation can be shortened. By shortening the time required for phase separation, the treatment speed of the water to be treated A can be increased. When the amine compound dissolves in water (water to be treated), it undergoes phase separation with a slurry containing a high concentration of solute, or the solute precipitates, so high solubility also contributes to improving the recovery rate.

[0068] The solubility of the amine compound of the embodiment is preferably 35 [g / L] or more. Although there is no particular upper limit to the solubility, for example, the solubility of the amine compound of the embodiment is preferably 1000 [g / L] or less.

[0069] The amine compound of the embodiment preferably has a high boiling point. Amine compounds with low boiling points are prone to volatilization. Because amines have a distinctive odor, it is preferable to use amines that are less likely to volatilize for water treatment. In addition, using an amine compound that is less likely to volatilize is also preferable because it increases the amine recovery efficiency, as described in the second and subsequent embodiments.

[0070] The boiling point of the amine compound of the embodiment at 1 atmospheric pressure is preferably 100° C. or higher, more preferably 150° C. or higher, and even more preferably 200° C. or higher. The upper limit of the boiling point is not particularly limited, but the boiling point of the amine compound of the embodiment at 1 atmospheric pressure is, for example, 500° C. or lower.

[0071] Phase separation can also be achieved using diisopropylamine, isopropylpropylamine, or 2-butylethylamine, which are compounds with a structure similar to that of the amine compound of the embodiment. However, these amine compounds have boiling points below 100°C and high vapor pressures of 30 Torr or more at room temperature (25°C) under atmospheric pressure (1 atmosphere (1 bar)). These amines are less practical in terms of solvent loss and odor. When a mixture of the amine compound of the embodiment and water is heated to 70°C, the water tends to evaporate. Therefore, heating an aqueous solution containing the amine compound of the embodiment increases the concentration of the amine compound, which is advantageous in terms of concentration. On the other hand, when a mixture of diisopropylamine, isopropylpropylamine, or 2-butylethylamine with water is heated to 70°C, the amine tends to evaporate. Therefore, heating an aqueous solution containing these amines decreases the concentration of the amine compound, which is disadvantageous in terms of concentration. Although diisopropylamine, isopropylpropylamine, and 2-butylethylamine have a structure similar to that of the amine compound of the embodiment, the reduction in evaporation during water treatment differs from that of the embodiment, which significantly affects concentration.

[0072] If a small amount of amine solution C is used, the amount of inorganic salts and / or organic matter precipitated in the water to be treated A is small, so it is preferable to use an appropriate amount of amine solution C depending on the amount of inorganic salts and / or organic matter contained in the water to be treated A. The total number of moles of the amine compounds of chemical formula (1) and / or chemical formula (2), whose solubility changes with temperature, in amine solution C is preferably equal to or greater than the total number of moles of inorganic salts and / or organic matter contained in the water to be treated A, more preferably equal to or greater than twice the total number of moles of inorganic salts and / or organic matter contained in the water to be treated A, and even more preferably equal to or greater than five times the total number of moles of inorganic salts and / or organic matter contained in the water to be treated A.

[0073] Specific examples of the amine compound of chemical formula (1) are shown in Figure 3. Below, the amine compounds of the embodiment will be explained using the compounds of chemical formulas (1-1) to (1-4) shown in Figure 3 as examples. The following explanation also applies to the compounds of other embodiments. For example, the explanation of the compound of chemical formula (1) also applies to the compound (2). That is, R1 For an explanation of 4 This corresponds to the explanation of R 2 and R 3 For an explanation of 5 , R 6 and R 7 This corresponds to the explanation of

[0074] The amine compound of chemical formula (1) will be explained using chemical formula (1-1) as an example. The amine compound of chemical formula (1-1) is R 1 is -CH2-CH2-CH2- and R 2 is -CHMe2, R 3 is -CHMe2. For example, 1,4-diaminobutane can be used instead of 1,3-diaminopropane. 1 The carbon chain of R can be made longer or shorter. 1 If R is a carbon chain with one carbon atom, the boiling point tends to be low, which is not preferable. 1 If the alkyl chain has a carbon number of 7 or more, the water solubility decreases and concentration in water treatment may become difficult. 1 When R is a linear alkyl chain, the number of carbon atoms is preferably 2 or more and 6 or less, and more preferably 2 or more and 4 or less. 1 When R is a linear alkyl chain, the number of carbon atoms can be selected by taking into account the ratio of [number of carbon atoms in the molecule] / [number of nitrogen atoms in the molecule]. 2 and R 3 have the same symmetrical structure, but the amine compound of formula (1) has R 1 or may have a symmetric structure centered on R 1 It may have an asymmetric structure centered on the center.

[0075] R 2 and R 3 When R is -Me, -Et, or -Pr, the steric hindrance of the amine compound of chemical formula (1) tends to be small, and the boiling point of the compound of chemical formula (1) tends to be low. Therefore, from the viewpoint of obtaining an amine compound with a higher boiling point, 3is preferably —CH(Me)Me, —CH(Et)Et, —CH(Me)Et, or —CH(Et)Pr.

[0076] The synthesis method of chemical formula (1-1) will be briefly explained. For example, acetone and 1,3-diaminopropane are heated and stirred in a solvent to synthesize an imine derivative, which is then reduced with sodium borohydride to bond isopropyl groups to the nitrogen atoms on both sides of the 1,3-diaminopropane. The resulting compound can be purified to obtain the amine compound of chemical formula (1-1).

[0077] In addition, by using an aldehyde or ketone instead of acetone, R 2 or / and R 3 It is possible to synthesize amine compounds with different R 2 and R 3 When both are small alkyl groups, the ratio of [number of carbon atoms in molecule] / [number of nitrogen atoms in molecule] may be less than 4. If the ratio of [number of carbon atoms in molecule] / [number of nitrogen atoms in molecule] is small, the amino group of the amine compound is oxidized, making the amine compound susceptible to deterioration. Also, if the ratio of [number of carbon atoms in molecule] / [number of nitrogen atoms in molecule] is small, the hydrogen bonds between the amine and water are difficult to break even when heated, making phase separation by heating after concentration difficult. Therefore, R 2 The number of carbon atoms contained in R 3 The total number of carbon atoms contained in R is preferably 3 or more and 10 or less, and more preferably 4 or more and 10 or less. 2 and R 3 The number of carbon atoms in at least one of R is preferably 3 or more and 6 or less. 2 and R 3 At least one of R has 3 to 6 carbon atoms, 2 The number of carbon atoms contained in R 3 The total number of carbon atoms contained in is preferably 4 or more and 10 or less.

[0078] Next, the amine compound of chemical formula (1) will be explained using chemical formula (1-2) as an example. The amine compound of chemical formula (1-2) is R 1 is -CH2-CH2- and R 2is -CHEt2, R 3 is -Me. The compound of formula (1-2) is R 2 and R 3 are different, so R 1 The compound of formula (1-2) has an asymmetric structure with the ratio of [number of carbon atoms in the molecule] to [number of nitrogen atoms in the molecule] being 4. This is slightly smaller than the ratio of [number of carbon atoms in the molecule] to [number of nitrogen atoms in the molecule] (=4.5) of the compound of formula (1-1), but R 2 has a slightly larger structure, so R 2 The hydrocarbon group of R in the chemical formula (1-2) is relatively bulky. Therefore, the compound of the chemical formula (1-2) is preferably used for water treatment according to the embodiment. 2 When the number of carbon atoms in the hydrocarbon group of (1-2) is reduced by one, the solubility of the amine compound in water increases, but the regeneration of the amine becomes difficult. In the compound of chemical formula (1-2), the number of carbon atoms can be increased up to a ratio of [number of carbon atoms in the molecule] / [number of nitrogen atoms in the molecule] of 7.0, within the range that satisfies the above-described conditions, and suitable water treatment can be performed.

[0079] Next, a method for synthesizing the compound represented by chemical formula (1-2) will be briefly described. For example, 3-pentanone and N-methylethylenediamine are heated and stirred in a solvent to synthesize an imine derivative, which is then reduced with sodium borohydride. The resulting compound is then purified to obtain the amine compound represented by chemical formula (1-2).

[0080] Next, the amine compound of chemical formula (1) will be explained using chemical formula (1-3) as an example. The amine compound of chemical formula (1-3) is R 1 is -(CH2-CH2-NH)2-(CH2-CH2)-, and R 2 is -CHEt2, R 3 is -Me. The compound of formula (1-3) is R 1 It is the same as the compound of chemical formula (1-2) except that R 1 Secondary aminoalkyl chains can also be used. 1Since a structure with a relatively large number of carbon atoms is used for [number of carbon atoms in molecule] / [number of nitrogen atoms in molecule] (the number of nitrogen atoms in the denominator varies depending on the nitrogen in the amino alkyl chain), R that satisfies the favorable relationship of [number of carbon atoms in molecule] / [number of nitrogen atoms in molecule] is 2 and R 3 The organic groups in R are somewhat restricted. 2 and R 3 It is not a requirement for a specific structure, but rather a R that has an appropriate value for [number of carbon atoms in molecule] / [number of nitrogen atoms in molecule] from the structures listed above. 2 and R 3 Specifically, -(CH2-CH2-NH) m -When the number of repetitions is 3, R is more likely to be 2 and R 3 This means selecting a hydrocarbon group with a large carbon number for R. From the viewpoint of performing suitable concentration and making it more difficult to evaporate than water during phase separation by heating, 1 is an aminoalkyl chain, R 2 or / and R 3 is preferably a branched alkyl group having 4 or more carbon atoms. 1 is an aminoalkyl chain, R 2 is a branched alkyl group having 5 to 7 carbon atoms, and R 3 is preferably a linear alkyl group having 1 to 3 carbon atoms. The number of carbon atoms in the hydrocarbon chain repeated in the aminoalkyl chain is preferably 3 in addition to the 2 carbon atoms explained above.

[0081] Also, R 2 or R 3 Amine compounds in which either or both of R are cyclic alkyl chains are also suitable as amine compounds of the present embodiment. The cyclic alkyl chain is preferably a cyclohexyl group or a cyclopentyl group. Both the cyclohexyl group and the cyclopentyl group are unsubstituted saturated hydrocarbon groups. 2 or R 3When an amine compound having a cyclic alkyl group in either one or both of the above is used for water treatment, the ratio of [number of carbon atoms in the molecule] / [number of nitrogen atoms in the molecule] must be between 4 and 7, or between 4 and 6. 1 amine compounds with aminoalkyl chains or R 1 can be selected from a linear alkyl chain having 2 to 6 carbon atoms, a branched alkyl chain having 4 to 6 carbon atoms, a cyclic alkyl chain having 5 or 6 carbon atoms, an ether chain having 2 to 6 carbon atoms, and an amino alkyl chain having 2 to 9 carbon atoms.

[0082] Next, a method for synthesizing the compound represented by formula (1-3) will be briefly described. For example, 3-pentanone and N-aminoethyl-N'-methyl-1,2-ethanediamine are heated and stirred in a solvent to synthesize an imine derivative, which is then reduced with sodium borohydride. The resulting compound is then purified to obtain the amine compound represented by formula (1-3).

[0083] Next, the compound of chemical formula (1) will be explained using chemical formula (1-4) as an example. The amine compound of chemical formula (1-4) is R 1 is -(CH2-CH2)-O-(CH2-CH2)-, and R 2 -CHEtMe, R 3 is -Pr. R 1 An ether chain can also be used for the R having an ether structure. The ether chain preferably has a straight chain structure without branching. 1 can be used in the same manner as a linear alkyl chain in the water treatment of the embodiment. 1 Whether or not a molecule has an ether structure containing an oxygen atom, the value of [number of carbon atoms in the molecule] / [number of nitrogen atoms in the molecule] and R 2 and R 3 Suitable water treatment can be carried out without adding any new restrictions to the hydrocarbon group of R 1 It is preferable that R has a symmetric structure with respect to the oxygen atom. 1 is preferably -CH2CH2CH2OCH2CH2CH2- or -CH2CH2OCH2CH2-.

[0084] Next, a method for synthesizing the compound represented by chemical formula (1-4) will be briefly described. For example, an imine derivative can be synthesized by heating and stirring the mixture in a solvent of 2-butanone and N-[2-(2-aminoethoxy)ethyl]-1-propanamine, and the resulting compound can be reduced with sodium borohydride and purified to obtain the amine compound represented by chemical formula (1-4).

[0085] The amine compounds of chemical formula (1), including chemical formulas (1-1) to (1-4) in FIG. 3, have high solubility at room temperature, a high boiling point, a low vapor pressure at room temperature, and excellent phase separation upon heating. Furthermore, the amine compounds of chemical formula (1), including chemical formulas (1-1) to (1-4), have a high vapor pressure at 25°C. When water treatment is performed using the amine compounds of chemical formula (1), including chemical formulas (1-1) to (1-4), at 10°C, a concentrated phase G appears. Furthermore, the lower critical solution temperature of the amine compounds of chemical formula (1), including chemical formulas (1-1) to (1-4), is in the range of 35°C to 90°C, so that the amines of the second and subsequent embodiments can be regenerated by gentle heating.

[0086] When using an amine solution C containing 50 wt % or more of an amine compound of chemical formula (1), which includes chemical formulas (1-1) to (1-4), the temperatures of the first mixture D and the second mixture E are preferably kept at room temperature or lower, and preferably 5°C to 38°C. If the process is carried out at a temperature higher than room temperature, the temperature in the uncontrolled area of ​​the apparatus will be lower than that of the first container, and solids may precipitate from the second mixture E or the supernatant phase F, causing pipe clogging.

[0087] Specific examples of the amine compound of chemical formula (2) are shown in FIG. 4. The amine compounds of the embodiment will be described below using the compounds of chemical formulas (2-1) to (2-5) shown in FIG. 4 as examples. The following description also applies to the compounds of other embodiments. For example, the description of the compound of chemical formula (2) also applies to the compound (1). That is, R 4 For an explanation of 1This corresponds to the explanation of R 5 , R 6 and R 7 For an explanation of 2 and R 3 This corresponds to the explanation of

[0088] The amine compound of chemical formula (2) will be explained using chemical formula (2-1) as an example. The amine compound of chemical formula (2-1) is R 4 is -CH2CH(Me)CH2-, and R 5 -CHEtMe, R 6 is -Et, R 7 is -Me. R 4 Suitable water treatment can also be achieved by using an amine compound having a branched saturated alkyl chain as the R 4 When using an amine compound with a branched saturated alkyl chain as the base, R is calculated by taking into account the ratio of [number of carbon atoms in the molecule] / [number of nitrogen atoms in the molecule]. 5 , R 6 and R 7 It is preferable to select the structure of the amine compound of formula (2) 5 is bonded to the nitrogen atom of the secondary amine structure. R of the amine compound of formula (2) 6 and R 7 is attached to a nitrogen bearing a tertiary amine structure.

[0089] R 4 When -CH2C(Me)2CH2- or -C(Me)2C(Me)2- is used instead of -CH2CH(Me)CH2-, the formula R is calculated by taking into account the ratio of [number of carbon atoms in the molecule] / [number of nitrogen atoms in the molecule]. 5 , R 6 and R 7 In order to adjust the value of [number of carbon atoms in molecule] / [number of nitrogen atoms in molecule] to a suitable range, it is preferable to select the structure of R 7 is preferably -Me, -Et, or -Pr. 7 When is -Me, -Et, or -Pr, it is possible to prevent the boiling point of the amine compound of chemical formula (2) from becoming too high, the solubility in water from decreasing, and the phase separation property from decreasing.

[0090] Next, a brief description of the synthesis method of chemical formula (2-1) will be given. For example, 2-butanone and N-ethyl-N',2-dimethyl-1,3-propane are heated and stirred in a solvent to synthesize an imine derivative, and this imine compound is then reduced with sodium borohydride. The resulting compound can then be purified to obtain the amine compound of chemical formula (2-1). The resulting compound can then be purified to obtain the amine compound of chemical formula (2-1).

[0091] Next, the amine compound of chemical formula (2) will be explained using chemical formula (2-2) as an example. The amine compound of chemical formula (2-2) is R 4 is -CH2-CH2- and R 5 is -C5H9 (cyclopentyl), and R 6 -Me, R 7 is -Me. R 5 Suitable water treatment can also be achieved by using an amine compound having a cyclic alkyl group as the R 5 When using an amine compound with a cyclic alkyl group as the amine, R is calculated by taking into account the ratio of [number of carbon atoms in the molecule] / [number of nitrogen atoms in the molecule]. 4 , R 6 and R 7 In consideration of the water solubility of the amine compound, it is preferable to select the structure of R 7 The total number of carbon atoms contained in is preferably 1 or 2.

[0092] Next, a synthesis method of the compound represented by formula (2-2) will be briefly explained. For example, cyclopentanone and N,N-dimethylethylenediamine are heated and stirred in a solvent to synthesize an imine derivative, and the imine compound is then reduced with sodium borohydride. The resulting compound is then purified to obtain the amine compound represented by formula (2-2).

[0093] Next, the amine compound of chemical formula (2) will be explained using chemical formula (2-3) as an example. The amine compound of chemical formula (2-3) is R 4 is -(C6H4)- (cyclic alkyl chain), and R 5 is -Et, R6 is -Et, R 7 is -Me. R 4 Suitable water treatment can also be achieved by using an amine compound having a cyclic alkyl chain as the R 4 When using an amine compound with a cyclic alkyl chain as the amine, R is calculated by taking into account the ratio of [number of carbon atoms in the molecule] / [number of nitrogen atoms in the molecule]. 5 , R 6 and R 7 In consideration of the water solubility of the amine compound, it is preferable to select the structure of R 7 The total number of carbon atoms contained in is preferably 1 or 2.

[0094] Next, a method for synthesizing the compound represented by formula (2-3) will be briefly described. For example, acetaldehyde and N-ethyl-N-methyl-1,2-cyclohexanediamine are heated and stirred in a solvent to synthesize an imine derivative, which is then reduced with sodium borohydride. The resulting compound is then purified to obtain the amine compound represented by formula (2-3).

[0095] Next, the amine compound of chemical formula (2) will be explained using chemical formula (2-4) as an example. The amine compound of chemical formula (2-2) is R 4 is -CH2-CH2- and R 5 -CHEtMe, R 6 is -CH2-CH2-OH, and R 7 is -Me. R 6 Suitable water treatment can also be achieved by using an amine compound containing a hydroxyl group as the R 6 When using an amine compound having a hydrocarbon group containing carbon, hydrogen, and an acid containing a hydroxyl group as the base, R is calculated by taking into account the ratio of [number of carbon atoms in the molecule] / [number of nitrogen atoms in the molecule]. 4 , R 5 and R 7 It is preferable to select the structure

[0096] Next, a method for synthesizing the compound represented by formula (2-4) will be briefly described. For example, 2-butanone and 2-[2-aminoethyl)methylamino]ethanol are heated and stirred in a solvent to synthesize an imine derivative, which is then reduced with sodium borohydride. The resulting compound is then purified to obtain the amine compound represented by formula (2-4). The resulting compound can be purified to obtain the amine compound of formula (2-4).

[0097] Next, the amine compound of chemical formula (2) will be explained using chemical formula (2-5) as an example. The amine compound of chemical formula (2-2) is R 4 is -CH2-CH2- and R 5 -CHEtMe, R 6 is -CH2-CH2-O-Me, R 7 is -Me. R 6 Suitable water treatment can also be achieved by using an amine compound containing an ether as the amine. 6 When using an amine compound with a hydrocarbon group containing carbon, hydrogen, and acid containing ether as the base, R is calculated by taking into account the ratio of [number of carbon atoms in the molecule] / [number of nitrogen atoms in the molecule]. 4 , R 5 and R 7 It is preferable to select the structure

[0098] Next, we will briefly explain the synthesis method of chemical formula (2-5). For example, N-(2-methoxyethyl)-N-methyl-1,2-ethanediamine is heated and stirred in a solvent to synthesize an imine derivative, and this imine compound is then reduced with sodium borohydride. The resulting compound is then purified to obtain the amine compound of chemical formula (2-5).

[0099] The amine compounds represented by chemical formulas (2-1) to (2-5) in FIG. 4 have high solubility at room temperature, high boiling points, and excellent phase separation properties upon heating. Furthermore, the amine compounds represented by chemical formulas (2-1) to (2-5) have low vapor pressures at 25°C. When water treatment is performed using the amine compounds represented by chemical formulas (2-1) to (2-5) at 10°C, a concentrated phase G appears. Furthermore, the lower critical solution temperature of the amine compounds represented by chemical formula (2) represented by chemical formulas (2-1) to (2-5) is within the range of 35°C to 90°C, making it possible to regenerate the amines of the second and subsequent embodiments with gentle heating.

[0100] When an amine solution C containing 50 wt % or more of an amine compound having any of chemical formulas (2-1) to (2-5) is used, the temperature of the first mixture D and the temperature of the second mixture E are preferably 5°C or more and 38°C or less.

[0101] The supernatant phase F is a mixture of the treated water A and the amine solution C, from which the solute and solvent (in the case of a slurry) have been partially removed. Raising the temperature changes the liquid nature of the amine solution C from hydrophilic to hydrophobic. When the supernatant phase F is heated, the LCST (Lower Critical Solution Temperature) of the amine solution C causes phase separation into an amine-rich phase and a water-rich phase. The amine compounds contained in the amine solution C can then be reused.

[0102] A first mixture D containing water to be treated A and an amine solution C is contained in a first container B.

[0103] In the embodiment, water treatment is carried out using the water to be treated A and the amine solution. By the water treatment of the embodiment, inorganic salts and / or organic substances contained in the water to be treated A are separated (concentrated).

[0104] The pH of the water to be treated A (measured at 25°C) is preferably 6 or more and 13 or less, more preferably 10 or more and 12 or less. If the pH of the first mixture D is less than 6, the alkaline amines will likely form salts, dissolve in water, and become unrecoverable, which is undesirable. If the pH of the water to be treated A is greater than 13, this is undesirable because it makes the equipment more susceptible to corrosion. An alkaline solution is preferably used to adjust the pH. At least one alkaline solution selected from the group consisting of sodium hydroxide, potassium hydroxide, potassium carbonate, and sodium bicarbonate is practical for use in adjusting the pH. To adjust the pH of the first mixture D, it is preferable to adjust the pH of the water to be treated A.

[0105] The water to be treated A and the amine solution C are mixed to obtain a first mixture D. Vigorous stirring may be performed during mixing. Regarding the ratio of the water to be treated A to the amine solution C, assuming that the volume of the water to be treated A is 1, the volume of the amine solution C (Solvent / Feed) is preferably 2 to 20, more preferably 2 to 15, and even more preferably 2 to 10. When the amine compound of the embodiment is used, salting out or concentration can be performed within the above-mentioned preferred Solvent / Feed range. When water treatment is performed using diisopropylamine as the amine compound so that the Solvent / Feed ratio is the same, concentration to a higher concentration than with diisopropylamine is possible. Furthermore, after phase separation by heating, diisopropylamine volatilizes due to its low boiling point, reducing the Solvent / Feed and decreasing the concentrated concentration. However, when the amine compound of the embodiment is used, water evaporates more easily than with the amine compound, so the Solvent / Feed value gradually increases, allowing stable salting out and concentration. Furthermore, when the amine compound of the embodiment is used, the volatilization of the amine compound is suppressed, so that the odor peculiar to amines can be suppressed, and an increase in operating costs due to the volatilization of the amine compound can also be suppressed.

[0106] The first mixture D, which contains the water to be treated A and the amine solution C contained in the first container B, is placed in a low-temperature environment, whereby the first mixture D undergoes phase separation into a supernatant phase F and a concentrated phase G. The temperature of the first mixture D during phase separation is preferably 3°C to 40°C, more preferably 5°C to 35°C. Furthermore, it is desirable to leave the first mixture D in the first container B for 5 minutes to 3 hours until the first mixture D separates into the supernatant phase F and the concentrated phase G (the time during which the first mixture D is being phase separated), or to perform a mechanical separation operation that utilizes the density difference between the supernatant phase F and the concentrated phase G. Heating the first mixture D here increases the salt solubility in the supernatant phase F, thereby decreasing the salt concentration in the concentrated phase G.

[0107] When the water to be treated A and the amine solution C are mixed, the amine compound dissolves in the water to be treated A, making the inorganic salts and / or organic substances dissolved in the water to be treated A less soluble, and making it easier for the inorganic salts and / or organic substances to be concentrated. This phase separation allows the inorganic salts and / or organic substances to be concentrated without utilizing the polarity reversal property.

[0108] The phase-separated second mixture E contains a supernatant phase F and a concentrated phase G. The concentrated phase G in the phase-separated second mixture E is a precipitate consisting of sediment or a liquid containing a high concentration of solute. If the separation of the supernatant phase F and the concentrated phase G is insufficient, the phase-separated second mixture E may be stirred, an amine solution C may be added, or the mixture may be cooled, or the phase-separated second mixture E from the first mixture D may be centrifuged.

[0109] The means 14 for separating the supernatant phase F and the concentrated phase G separates the supernatant phase F and the concentrated phase G. The means 14 for separating the supernatant phase F and the concentrated phase G includes a mechanism for discharging either or both of the supernatant phase F and the concentrated phase G from the first container B from the second mixture E obtained by phase separation of the first mixture D. An example of the means 14 for separating the supernatant phase F and the concentrated phase G is a pump that extracts the supernatant phase F from the upper side of the first container B. Another example of the means 14 for separating the supernatant phase F and the concentrated phase G is a filter at the bottom of the first container B through which the concentrated phase G is filtered and an opening that can be controlled to open and close using a cock or the like. The concentrated phase G remains in the filter, and the supernatant phase F can be discharged from the opening to separate the supernatant phase F and the concentrated phase G. The concentrated phase G remaining in the filter can then be collected, allowing the supernatant phase F and the concentrated phase G to be separately discharged from the first container B. Alternatively, the second mixture E obtained by phase separation of the first mixture D can be transferred to another container and then similarly separated into a supernatant phase F and a concentrated phase G. The mesh size of the filter is appropriately selected depending on the substance contained in the concentrated phase G.

[0110] In the water treatment system 100 and water treatment method of the embodiment, an amine whose liquid property changes in response to temperature is used, and inorganic salts and / or organic substances contained in the water to be treated A can be efficiently separated. In the water treatment system 100 and water treatment method, inorganic salts and / or organic substances contained in the water to be treated A can be efficiently recovered under low-temperature conditions. This can be done with much less energy than concentrating the water to be treated A by evaporating the water contained in the water to be treated A.

[0111] Furthermore, from the viewpoints of promoting salting out, promoting phase separation, and increasing the concentration of the substance to be recovered in the concentrated phase G, it is preferable to add carbon dioxide to the first mixture D and / or the second mixture E. The amine compound of the embodiment undergoes polarity conversion in response to carbon dioxide, and the solubility of the amine compound in an aqueous solution increases in a solution with a high carbon dioxide concentration, while the water solubility of the amine compound decreases in a solution with a low carbon dioxide concentration.

[0112] (Second embodiment) The second embodiment relates to a water treatment system and method that are applied to non-evaporative extraction and separation by concentration using an amine compound whose hydrophobicity and hydrophilicity change in response to heat. The second embodiment is an application example of the first embodiment. In the second embodiment, water treatment is performed by utilizing the LCST (Lower Critical Solution Temperature) phenomenon of an amine compound of the embodiment that is hydrophilic at low temperatures.

[0113] FIG. 5 shows a schematic diagram of a water treatment system 200 according to a second embodiment. The schematic diagram of the water treatment system 200 in FIG. 5 includes a means 11 for introducing water to be treated A into a first container B, a means 12 for introducing an amine solution C into the first container B to obtain a first mixture D, a temperature control means 13 for controlling the temperature, a means 14 for separating a supernatant phase F and a concentrated phase G from a second mixture E obtained by phase separation of the first mixture D containing the water to be treated A and the amine solution C, and a means 15 for separating the supernatant phase F into an aqueous phase H and an organic phase (amine phase) J to separate and recover the amine (organic phase J). A filter 20 is preferably provided between the means 14 for separating the supernatant phase F and the concentrated phase G and the means 15 for separating and recovering the amine compound. The mesh size of the filter 16 is appropriately selected depending on the substance to be filtered by the filter.

[0114] The water treatment system 200 of the second embodiment has a means 15 for separating the supernatant phase F into an aqueous phase H and an organic phase J to separate and recover the amine (organic phase J), ​​and the separated and recovered amine (organic phase J) is mixed with the amine solution C via a means 12 for introducing the amine solution C into a first container B to obtain a first mixture D. In the second embodiment, a description of the contents common to the first embodiment will be omitted.

[0115] 6 shows a flowchart of a water treatment method according to a second embodiment. The water treatment method of the embodiment preferably includes the steps of: obtaining a first mixture D by mixing water to be treated A and an amine solution C; subjecting the first mixture D to phase separation at a low temperature to obtain a phase-separated second mixture E; separating a supernatant phase F from a concentrated phase G of the phase-separated second mixture E; and heating the supernatant phase F to separate it into an aqueous phase H and an organic phase J, thereby separating and recovering the amine compound. The water treatment method of the second embodiment includes the steps of: separating the supernatant phase F into an aqueous phase H and an organic phase J using means 15 for separating the supernatant phase F into an aqueous phase H and an organic phase J, thereby separating and recovering the amine compound. Hereinafter, the water treatment system 200 will be described, and the description of the water treatment system 200 also includes the description of the water treatment method.

[0116] The supernatant phase F separated by the means 14 for separating the supernatant phase F and the concentrated phase G is treated by the means 15 for separating the supernatant phase F into an aqueous phase H and an organic phase J to separate and recover the amine compounds. The supernatant phase F is an aqueous solution in which amines are dissolved. The supernatant phase F may contain trace amounts of inorganic salts and / or organic substances. A filter 16 is preferably provided on the path from the means 14 for separating the supernatant phase F and the concentrated phase G to the means 15 for separating and recovering the amine compounds. The supernatant phase F may contain some precipitated solid inorganic salts and / or organic substances. It is preferable to provide the filter 16 to remove the solid inorganic salts and / or organic substances contained in the supernatant phase F, thereby reducing the amount of solid inorganic salts and / or organic substances flowing into the means 15 for separating the supernatant phase F into an aqueous phase and an organic phase to separate and recover the amine compounds.

[0117] The means 15 for separating and recovering the amine compound by phase separation of the supernatant phase F into an aqueous phase H and an organic phase J separates and recovers the amine compound contained in the supernatant phase F. The means 15 for separating and recovering the amine compound by phase separation of the supernatant phase into an aqueous phase H and an organic phase J preferably uses a mechanism for heating the supernatant phase F. For example, the supernatant phase F is placed in a second container (not shown) and heated in the second container. As the temperature of the supernatant phase F increases, the compatibility of the amine compound of the embodiment with water changes, causing separation into an organic phase and an aqueous phase. The supernatant phase separates into an aqueous phase H and an organic phase J at a temperature higher than that at which the first mixture D phase separates. It is preferable to heat the supernatant phase F to a temperature higher than that of the first mixture D (the temperature at which the first mixture D phase separates (the temperature at which the supernatant phase F and the concentrated phase G are separated)). It is preferable to heat the supernatant phase F to a temperature at least 5°C higher than the temperature at which the first mixture D is phase separated (the temperature at which the supernatant phase F and the concentrated phase G are separated). It is preferable to heat the supernatant phase F to a temperature at least 10°C higher than the temperature at which the first mixture D is phase separated (the temperature at which the supernatant phase F and the concentrated phase G are separated). It is preferable to heat the supernatant phase F to a temperature at least 20°C higher than the temperature at which the first mixture D is phase separated (the temperature at which the supernatant phase F and the concentrated phase G are separated). It is preferable to heat the supernatant phase F to a temperature at least 20°C higher than the temperature at which the first mixture D is phase separated. It is preferable to heat the supernatant phase F to a temperature at least 30°C higher than the temperature at which the first mixture D is phase separated (the temperature at which the supernatant phase F and the concentrated phase G are separated). The supernatant phase F is preferably heated to a temperature of 35°C or higher and 90°C or lower, more preferably 35°C or higher and 75°C or lower from the viewpoint of reducing energy consumption. The supernatant phase F preferably undergoes phase separation at a temperature of 35°C or higher and 90°C or lower. From the viewpoint of reducing energy consumption, the supernatant phase F more preferably undergoes phase separation at a temperature of 35°C or higher and 75°C or lower. The supernatant phase F is preferably heated using waste heat generated in a plant or the like.

[0118] When supernatant phase F is heated, the compatibility of the amine compound with water changes, and supernatant phase F separates into aqueous phase H and organic phase J. Aqueous phase H contains the amine compound, inorganic salts, and / or organic substances dissolved in water. Organic phase J contains the amine whose compatibility with water changes in response to heat, and organic phase J is returned to amine solution C to reuse the amine compound whose compatibility with water changes in response to heat.

[0119] From the viewpoint of recovering the amine from the supernatant phase F, it is preferable to use the amine contained in the supernatant phase F, that is, the amine compound of the embodiment contained in the amine solution C.

[0120] The supernatant phase F containing the amine compound of the embodiment is confirmed to undergo phase separation at 90°C.

[0121] The amine compound contained in the amine solution C is preferably the amine compound of the first embodiment shown in Figures 3 and 4 from two perspectives: recovering the amine from the supernatant phase F and extracting and separating inorganic salts and / or organic matter from the treated water A.

[0122] The water treatment system 200 and water treatment method of the embodiment use an amine whose liquid property changes in response to temperature, and can efficiently recover the amine from the supernatant phase F that is generated when inorganic salts and / or organic substances contained in the water to be treated A are separated. In the water treatment system 200 and water treatment method, the supernatant phase F is gently heated to cause phase separation of the supernatant phase F, allowing the recovery of the amine used to precipitate the inorganic salts and / or organic substances. This can be done with much less energy than concentrating the supernatant phase F by evaporating the water contained in the supernatant phase F. Therefore, the water treatment system 200 can be operated with low energy consumption and a low environmental impact overall.

[0123] Furthermore, from the viewpoints of promoting salting out, promoting phase separation, and increasing the concentration of the substance to be recovered in the concentrated phase G, it is preferable to add carbon dioxide to the first mixture D and / or the second mixture E. The amine compound of this embodiment undergoes polarity conversion in response to carbon dioxide, so that the solubility of the amine compound in an aqueous solution increases in a solution with a high carbon dioxide concentration, and the water solubility of the amine compound decreases in a solution with a low carbon dioxide concentration. Therefore, when the supernatant phase F is heated, the added carbon dioxide is released from the supernatant phase F, causing it to separate into an aqueous phase H and an organic phase J.

[0124] (Third embodiment) The third embodiment relates to a water treatment system and method applicable to non-evaporative extraction separation (desalination) through concentration using an amine compound whose hydrophobicity and hydrophilicity change in response to heat. The third embodiment is an application of the first and second embodiments. Figure 7 shows a schematic diagram of a water treatment system 300 according to the third embodiment. The schematic diagram of the water treatment system 300 in Figure 7 includes: means 11 for introducing water to be treated A into a first container B; means 12 for introducing an amine solution C into the first container B to obtain a first mixture D; temperature control means 13 for controlling the temperature; means 14 for separating a supernatant phase F and a concentrated phase G from a second mixture E obtained by phase separation of the first mixture D containing the water to be treated A and the amine solution C; means 15 for separating the supernatant phase F into an aqueous phase H and an organic phase J to separate and recover the amine (organic phase J); and means 16 for treating the aqueous phase H with a reverse osmosis (RO) membrane. Depending on the characteristics of the amine molecules, a nanofiltration (NF) membrane may be used instead of the RO membrane.

[0125] The water treatment system 300 of the third embodiment has a means 16 for treating the aqueous phase H with an RO membrane, and has the same structure as the water treatment system 200 of the second embodiment except that the obtained highly pure water M is discharged and the concentrated water L is returned to the first container B. In the third embodiment, a description of the contents common to the second embodiment will be omitted.

[0126] 8 shows a flowchart of a water treatment method according to a third embodiment. The water treatment method according to the embodiment preferably includes the steps of: obtaining a first mixture D by mixing water to be treated A and an amine solution C; subjecting the first mixture D to phase separation at a low temperature to obtain a phase-separated second mixture E; separating a supernatant phase F from a concentrated phase G of the phase-separated second mixture E; heating the supernatant phase F to separate it into an aqueous phase H and an organic phase J to separate and recover the amine compound; and treating the aqueous phase H with a reverse osmosis membrane (RO membrane). In the water treatment method according to the third embodiment, a step of treating the aqueous phase H with an RO membrane is performed in means 16 for treating the aqueous phase H with an RO membrane. Hereinafter, a water treatment system 300 will be described, and the description of the water treatment system 300 also includes a description of the water treatment method.

[0127] The resulting highly pure water M contains almost no impurities because it has been treated with an RO membrane, and can be released into rivers, etc., if the water quality conditions are met. Treating the untreated water A directly with an RO membrane would incur very high power costs, but by treating the aqueous phase H, which is much smaller in volume than the untreated water A, with an RO membrane, highly pure water M can be obtained efficiently.

[0128] The concentrated water L obtained by treatment with the RO membrane is preferably returned to the first container B through a return flow path and subjected to concentration treatment again. The concentrated water L contains the amine contained in the amine solution C in addition to the inorganic salts and / or organic matter contained in the water to be treated A. Therefore, by performing water treatment in a cyclical manner, the amount that can be recovered in the concentrated phase G increases. The concentrated water L can also be returned to the first container B via the means 11 that introduces the water to be treated A into the first container B. Alternatively, the concentrated water L can be used as water to be treated in another water treatment without being returned to the first container B.

[0129] When the water to be treated A contains a high concentration of salt, the osmotic pressure of the treated water is high and general RO membrane treatment technology cannot be applied. In any of the water treatment systems of the embodiments, the water to be treated A can be treated even with a high salt concentration, and high-purity water M can be obtained by finally subjecting the low-concentration aqueous phase H to RO membrane treatment.

[0130] In the water treatment system 300 and water treatment method of the embodiment, an amine whose liquid property changes in response to heat is used to efficiently separate the inorganic salts and / or organic matter contained in the water to be treated A, and the supernatant phase F that is generated when this is separated can be further phase-separated to obtain highly pure water M and concentrated water L. The water treatment system 300 and water treatment method can perform a circulatory water treatment that separates the water to be treated A into both the inorganic salts and / or organic matter in the concentrated phase G and the highly pure water M. As described for the water treatment system 100 of the first embodiment and the water treatment system 200 of the second embodiment, the water treatment system 200 can be operated with low energy and low environmental load overall, and can efficiently produce highly pure water M that can be discharged into rivers, etc.

[0131] Examples of the embodiment will be described below. Example A A 10 wt% NaCl aqueous solution and the amine compounds listed in the table in Figure 9 were placed in a stoppered measuring cylinder, which was then stopped up and stirred at room temperature (25°C), after which the mixture was allowed to stand. The volume was adjusted so that the volume ratio of solvent to water being treated (Solvent / Feed (S / F)) was 2.0, 5.0, 7.0, 10.0, 15.4, 18.0, or 20.0. After allowing the mixture to stand for 5 minutes, the presence or absence of salt precipitation was evaluated. The results are summarized in the table in Figure 9. Cases where salt precipitated were evaluated as X, and cases where a concentrated phase G was obtained without salt precipitation were evaluated as Y.

[0132] The results shown in the table in Figure 9 demonstrate that a secondary amine compound whose compatibility with water changes with heat can be used to efficiently concentrate or salt out saltwater from a salt-containing aqueous solution with a small amount of solvent. The salt concentration of the concentrated water, the amount of precipitated salt, and the amount of amine compound required for concentration varied depending on the dissolution of the secondary amine compound in the treated water A. This is thought to depend on the structure, solubility, and polarity of the amine. When the solution was stirred at room temperature (25°C) and then left to stand for a long period of time, no decrease in salt concentration was observed in the examples. However, when diisopropylamine was used in the comparative example, the salt concentration decreased because diisopropylamine is more volatile than water, even at room temperature. Furthermore, after standing, whether salt precipitated or concentrated was evaluated, and the supernatant was heated to 70°C, the supernatant separated into an aqueous phase and an organic phase containing the amine compound. High-purity water could be obtained from the aqueous phase by RO membrane treatment. In the examples using the amine compound of the embodiment, a concentrated phase G (liquid phase (concentrated in the table) or solid phase (precipitated in the table)) was obtained from a small amount of water. Even when the S / F is 5 or less, the salt removal rate is high, and the amine compound of the embodiment is highly practical.

[0133] Example B A 10 wt% NaCl aqueous solution and the amine compounds listed in the table in Figure 9 were placed in a stoppered measuring cylinder, which was then stopped up and stirred at room temperature (25°C), after which the mixture was allowed to stand. The volume was adjusted so that the volume ratio of solvent to water being treated (Solvent / Feed (S / F)) was 2.0, 3.0, 4.0, 5.0, 7.0, 10.0, or 14.0. After allowing the mixture to stand for 5 minutes, it was evaluated whether salt had precipitated or concentrated. The results are summarized in the table in Figure 10. If salt precipitated, it was rated as - (hyphen); if no salt precipitated and the salt concentration in concentrated phase G was 24 wt% or more but less than the saturated concentration, it was rated as A; if no salt precipitated and the salt concentration in concentrated phase G was 20 wt% or more but less than 24 wt%, it was rated as B; if no salt precipitated and the salt concentration in concentrated phase G was 15 wt% or more but less than 20 wt%, it was rated as C; and if no salt precipitated and the salt concentration in concentrated phase G was less than 15 wt%, it was rated as D.

[0134] From the results shown in the table in Figure 10, the differences between the amine compound of the embodiment and diisopropylamine were evaluated in detail by evaluating the salt concentration of concentrated phase G, which was evaluated as Y in Example A. Although the ratio of [number of carbon atoms in molecule] to [number of nitrogen atoms in molecule] of diisopropylamine is 6, it can be seen that the salt concentration of concentrated phase G is lower than in the example. The table in Figure 10 shows that by using the amine compound of the embodiment, the amount of amine compound required to achieve the same level of concentration can be much smaller than when diisopropylamine is used for concentration. The amine compound used in the example was able to achieve sufficient concentration even with an S / F of about 4, and the amine compound of the embodiment is highly practical.

[0135] Example C A 10 wt% NaCl aqueous solution and the amine compounds listed in the table in Figure 11 were placed in a stoppered measuring cylinder, the cylinder was closed, and the mixture was stirred at room temperature (25°C) and then allowed to stand. The volume was adjusted so that the volume ratio of solvent to water being treated (Solvent / Feed (S / F)) was 10.0. After allowing the mixture to stand for 5 minutes, the salt concentration was evaluated. Cases in which the salt concentration in the concentrated phase was higher than that of the comparative example using diisopropylamine or in which salt precipitated were evaluated as A, and cases in which the salt concentration in the concentrated phase was equal to or lower than that of the comparative example using diisopropylamine were evaluated as B. The results are summarized in Figure 11.

[0136] The results shown in the table in Figure 11 indicate that when the amine compounds of the embodiments were used, the samples were concentrated to a higher concentration or salted out compared to when diisopropylamine was used. The amine compounds used in the examples were able to be sufficiently concentrated even at an S / F of about 10, demonstrating the high practical utility of the amine compounds of the embodiments.

[0137] Although several embodiments of the present invention have been described, these embodiments are presented as examples and are not intended to limit the scope of the invention. These embodiments can be implemented in various other forms, and various omissions, substitutions, modifications, and combinations can be made without departing from the spirit of the invention. These embodiments and their modifications are included within the scope and spirit of the invention, as well as the inventions described in the claims and their equivalents.

[0138] The technical solutions of the embodiments are described below. Technical proposal 1 a means for introducing water to be treated into the first container; means for introducing an amine solution into said first vessel to provide a first mixture; and means for separating the supernatant phase and the concentrated phase of the second mixture resulting from the phase separation of the first mixture; The amine solution contains an amine compound represented by chemical formula (1) or / and chemical formula (2), R of the chemical formula (1) 1 is a linear alkyl chain having 2 to 6 carbon atoms, a branched alkyl chain having 4 to 6 carbon atoms, a cyclic alkyl chain having 5 or 6 carbon atoms, an ether chain having 2 to 6 carbon atoms, or an amino alkyl chain having 2 to 9 carbon atoms, R of the chemical formula (1) 2 is a hydrocarbon group having 1 to 6 carbon atoms, R of the chemical formula (1) 3 is a hydrocarbon group having 1 to 6 carbon atoms, In the chemical formula (1), the ratio of the number of carbon atoms in the molecule to the number of nitrogen atoms in the molecule is 4.0 or more and 7.0 or less, R of the above chemical formula (2) 4 is a linear alkyl chain having 2 to 6 carbon atoms, a branched alkyl chain having 4 to 6 carbon atoms, a cyclic alkyl chain having 5 or 6 carbon atoms, an ether chain having 2 to 6 carbon atoms, or an amino alkyl chain having 2 to 9 carbon atoms, R of the above chemical formula (2) 5 is a hydrocarbon group having 1 to 6 carbon atoms, R of the above chemical formula (2) 6is a hydrocarbon group having 1 to 6 carbon atoms, R of the above chemical formula (2) 7 is a hydrocarbon group having 1 to 6 carbon atoms, A water treatment system, wherein in the chemical formula (2), [number of carbon atoms in the molecule] / [number of nitrogen atoms in the molecule] is 4.0 or more and 7.0 or less. Technical proposal 2 R of the chemical formula (1) 1 is a linear alkyl chain having 2 to 6 carbon atoms, a branched alkyl chain having 4 to 6 carbon atoms, or a cyclic alkyl chain having 5 or 6 carbon atoms, and the cyclic alkyl chain is unsubstituted and the first carbon atom of the cyclic alkyl chain is R 2 The carbon atom at the 2nd position of the cyclic alkyl chain is bonded to the nitrogen atom bonded to R 3 a cyclic alkyl chain, a linear ether chain having 2 to 6 carbon atoms, or a linear aminoalkyl chain having 2 to 9 carbon atoms, bonded to the nitrogen bonded to the R of the chemical formula (1) 2 is a hydrocarbon group having 1 to 6 carbon atoms and consisting of carbon and hydrogen, or a hydrocarbon group having 1 to 6 carbon atoms and consisting of carbon, hydrogen, and oxygen, R of the chemical formula (1) 3 is a hydrocarbon group having 1 to 6 carbon atoms and consisting of carbon and hydrogen, or a hydrocarbon group having 1 to 6 carbon atoms and consisting of carbon, hydrogen, and oxygen, R of the above chemical formula (2) 4 is a linear alkyl chain having 2 to 6 carbon atoms, a branched alkyl chain having 4 to 6 carbon atoms, or a cyclic alkyl chain having 5 or 6 carbon atoms, and the cyclic alkyl chain is unsubstituted and the first carbon atom of the cyclic alkyl chain is R 2 The carbon atom at the 2nd position of the cyclic alkyl chain is bonded to the nitrogen atom bonded to R 3 a cyclic alkyl chain bonded to the nitrogen bonded to the alkyl group, a cyclic alkyl chain having 5 or 6 carbon atoms, a linear ether chain having 2 to 6 carbon atoms, or a linear amino alkyl chain having 2 to 9 carbon atoms; R of the above chemical formula (2) 5 is a hydrocarbon group having 1 to 6 carbon atoms and consisting of carbon and hydrogen, or a hydrocarbon group having 1 to 6 carbon atoms and consisting of carbon, hydrogen, and oxygen, R of the above chemical formula (2) 6is a hydrocarbon group having 1 to 6 carbon atoms and consisting of carbon and hydrogen, or a hydrocarbon group having 1 to 6 carbon atoms and consisting of carbon, hydrogen, and oxygen, R of the above chemical formula (2) 7 is a hydrocarbon group having 1 to 6 carbon atoms and consisting of carbon and hydrogen, or a hydrocarbon group having 1 to 6 carbon atoms and consisting of carbon, hydrogen, and oxygen. Technical proposal 3 R of the chemical formula (1) 1 is a linear alkyl chain having 2 to 6 carbon atoms, a branched alkyl chain having 4 to 6 carbon atoms, or a cyclic alkyl chain having 5 or 6 carbon atoms, and the cyclic alkyl chain is unsubstituted and the first carbon atom of the cyclic alkyl chain is R 2 The carbon atom at the 2nd position of the cyclic alkyl chain is bonded to the nitrogen atom bonded to R 3 a linear ether chain having 2 to 6 carbon atoms and an ether chain having an alkyl chain having 2 or 3 carbon atoms bonded to oxygen, or a linear aminoalkyl chain having 2 to 9 carbon atoms, wherein the amino group contained in the aminoalkyl chain is secondary, the number of amino groups contained in the aminoalkyl chain is 1 to 3, and the linear alkyl chain having 2 or 3 carbon atoms is bonded to the amino group of the aminoalkyl chain; R of the chemical formula (1) 2 is a saturated hydrocarbon group having 1 to 6 carbon atoms and consisting of carbon and hydrogen, or a saturated hydrocarbon group having 1 to 6 carbon atoms and consisting of carbon, hydrogen, and oxygen, R of the chemical formula (1) 3 is a saturated hydrocarbon group having 1 to 6 carbon atoms and consisting of carbon and hydrogen, or a saturated hydrocarbon group having 1 to 6 carbon atoms and consisting of carbon, hydrogen, and oxygen, R of the above chemical formula (2) 4 is a linear alkyl chain having 2 to 6 carbon atoms, a branched alkyl chain having 4 to 6 carbon atoms, or a cyclic alkyl chain having 5 or 6 carbon atoms, and the cyclic alkyl chain is unsubstituted and the first carbon atom of the cyclic alkyl chain is R 2 The carbon atom at the 2nd position of the cyclic alkyl chain is bonded to the nitrogen atom bonded to R 3a cyclic alkyl chain bonded to a nitrogen atom bonded to the oxygen atom, a cyclic alkyl chain having 5 or 6 carbon atoms, a linear ether chain having 2 to 6 carbon atoms, and an alkyl chain having 2 or 3 carbon atoms bonded to the oxygen atom, or a linear amino alkyl chain having 2 to 9 carbon atoms, wherein the amino group contained in the amino alkyl chain is secondary, the number of amino groups contained in the amino alkyl chain is 1 to 3, and the linear alkyl chain having 2 or 3 carbon atoms is bonded to the amino group of the amino alkyl chain, R of the above chemical formula (2) 5 is a saturated hydrocarbon group having 1 to 6 carbon atoms and consisting of carbon and hydrogen, or a saturated hydrocarbon group having 1 to 6 carbon atoms and consisting of carbon, hydrogen, and oxygen, R of the above chemical formula (2) 6 is a saturated hydrocarbon group having 1 to 6 carbon atoms and consisting of carbon and hydrogen, or a saturated hydrocarbon group having 1 to 6 carbon atoms and consisting of carbon, hydrogen, and oxygen, R of the above chemical formula (2) 7 is a saturated hydrocarbon group having 1 to 6 carbon atoms and consisting of carbon and hydrogen, or a saturated hydrocarbon group having 1 to 6 carbon atoms and consisting of carbon, hydrogen, and oxygen. Technical proposal 4 R of the chemical formula (1) 1 is a linear alkyl chain having 2 to 6 carbon atoms, a branched alkyl chain having 4 to 6 carbon atoms, or a cyclic alkyl chain having 5 or 6 carbon atoms, and the cyclic alkyl chain is unsubstituted and the first carbon atom of the cyclic alkyl chain is R 2 The carbon atom at the 2nd position of the cyclic alkyl chain is bonded to the nitrogen atom bonded to R 3 a cyclic alkyl chain bonded to a nitrogen atom bonded to the oxygen atom, a linear ether chain having 2 to 6 carbon atoms, an ether chain having an alkyl chain having 2 or 3 carbon atoms bonded to the oxygen atom, or a linear aminoalkyl chain having 2 to 9 carbon atoms, in which the amino group contained in the aminoalkyl chain is secondary, and the number of amino groups contained in the aminoalkyl chain is from 1 to 3, and an aminoalkyl chain in which a linear alkyl chain having 2 or 3 carbon atoms is bonded to the amino group of the aminoalkyl chain, R of the chemical formula (1) 2 is a saturated hydrocarbon group having 1 to 6 carbon atoms and consisting of carbon and hydrogen, R of the chemical formula (1) 3is a saturated hydrocarbon group having 1 to 6 carbon atoms and consisting of carbon and hydrogen, or an ether group or alcohol group having 1 to 6 carbon atoms and consisting of carbon, hydrogen, and oxygen, R of the above chemical formula (2) 4 is a linear alkyl chain having 2 to 6 carbon atoms, a branched alkyl chain having 4 to 6 carbon atoms, or a cyclic alkyl chain having 5 or 6 carbon atoms, wherein the cyclic alkyl chain is unsubstituted and the carbon atom at position 1 of the cyclic alkyl chain is bonded to the nitrogen bonded to R2 and the carbon atom at position 2 of the cyclic alkyl chain is bonded to the nitrogen bonded to R3; a cyclic alkyl chain having 5 or 6 carbon atoms, a linear ether chain having 2 to 6 carbon atoms, in which an alkyl chain having 2 or 3 carbon atoms is bonded to the oxygen atom, or a linear aminoalkyl chain having 2 to 9 carbon atoms, in which the amino group in the aminoalkyl chain is secondary and the number of amino groups in the aminoalkyl chain is 1 to 3, and the linear alkyl chain having 2 or 3 carbon atoms is bonded to the amino group of the aminoalkyl chain; R of the above chemical formula (2) 5 is a saturated hydrocarbon group having 1 to 6 carbon atoms and consisting of carbon and hydrogen, or an ether group or alcohol group having 1 to 6 carbon atoms and consisting of carbon, hydrogen, and oxygen, R of the above chemical formula (2) 6 is a saturated hydrocarbon group having 1 to 6 carbon atoms and consisting of carbon and hydrogen, or an ether group or alcohol group having 1 to 6 carbon atoms and consisting of carbon, hydrogen, and oxygen, R of the above chemical formula (2) 7 A water treatment system according to any one of Technical Schemes 1 to 3, wherein the carbon number is 1 to 6 and the saturated hydrocarbon group is composed of carbon and hydrogen. Technical proposal 5 R of the above chemical formula (2) 4is a linear alkyl chain having 2 to 6 carbon atoms, a branched alkyl chain having 4 to 6 carbon atoms, or a cyclic alkyl chain having 5 or 6 carbon atoms, wherein the cyclic alkyl chain is unsubstituted and the carbon atom at position 1 of the cyclic alkyl chain is bonded to the nitrogen bonded to R2 and the carbon atom at position 2 of the cyclic alkyl chain is bonded to the nitrogen bonded to R3; a cyclic alkyl chain having 5 or 6 carbon atoms, a linear ether chain having 2 to 6 carbon atoms, in which an alkyl chain having 2 or 3 carbon atoms is bonded to the oxygen atom, or a linear aminoalkyl chain having 2 to 9 carbon atoms, in which the amino group in the aminoalkyl chain is secondary and the number of amino groups in the aminoalkyl chain is 1 to 3, and the linear alkyl chain having 2 or 3 carbon atoms is bonded to the amino group of the aminoalkyl chain; R of the above chemical formula (2) 5 is a saturated hydrocarbon group having 1 to 6 carbon atoms and consisting of carbon and hydrogen, or an ether group or alcohol group having 1 to 6 carbon atoms and consisting of carbon, hydrogen, and oxygen, R of the above chemical formula (2) 6 is a saturated hydrocarbon group having 1 to 3 carbon atoms and consisting of carbon and hydrogen, or an ether group or alcohol group having 1 to 3 carbon atoms and consisting of carbon, hydrogen, and oxygen, R of the above chemical formula (2) 7 A water treatment system according to any one of Technical Schemes 1 to 4, wherein the carbon number is 1 to 3 and the saturated hydrocarbon group is composed of carbon and hydrogen. Technical proposal 6 R of the above chemical formula (2) 4 is a linear alkyl chain having 2 to 6 carbon atoms, a branched alkyl chain having 4 to 6 carbon atoms, or a cyclic alkyl chain having 5 or 6 carbon atoms, wherein the cyclic alkyl chain is unsubstituted and the carbon atom at position 1 of the cyclic alkyl chain is bonded to the nitrogen bonded to R2 and the carbon atom at position 2 of the cyclic alkyl chain is bonded to the nitrogen bonded to R3; a cyclic alkyl chain having 5 or 6 carbon atoms, a linear ether chain having 2 to 6 carbon atoms, in which an alkyl chain having 2 or 3 carbon atoms is bonded to the oxygen atom, or a linear aminoalkyl chain having 2 to 9 carbon atoms, in which the amino group in the aminoalkyl chain is secondary and the number of amino groups in the aminoalkyl chain is 1 to 3, and the linear alkyl chain having 2 or 3 carbon atoms is bonded to the amino group of the aminoalkyl chain; R of the above chemical formula (2) 5 is a saturated hydrocarbon group having 1 to 6 carbon atoms and consisting of carbon and hydrogen, or an ether group or alcohol group having 1 to 6 carbon atoms and consisting of carbon, hydrogen, and oxygen, R of the above chemical formula (2) 6 is a saturated hydrocarbon group having 1 or 2 carbon atoms and consisting of carbon and hydrogen, or an ether group or alcohol group having 1 to 3 carbon atoms and consisting of carbon, hydrogen, and oxygen, R of the above chemical formula (2) 7 A water treatment system according to any one of Technical Schemes 1 to 5, wherein is a saturated hydrocarbon group having 1 or 2 carbon atoms and consisting of carbon and hydrogen. Technical proposal 7 R of the chemical formula (1) 1 -CH2CH2-, -CH2CH2CH2-, -CH2CH2CH2CH2-, -CH2CH2CH2CH2CH2-, -CH2CH2CH2CH2CH2CH2-, -(CH2CH2NH) n -(CH2CH2) m -(n is 1 to 3, m is 1), -(CH2CH2CH2NH) p -(CH2CH2CH2) q -(p is 1 or 2, q is 1), -CH2CH2CH2OCH2CH2CH2-, -CH2CH2OCH2CH2-, -CH2CH(Me)CH2-, -CH2C(Me)2CH2-, -C(Me)2C(Me)2-, or the cyclic alkyl chain -(CH4)-; R of the chemical formula (1) 2 is -Me, -Et, -Pr, -CH(Me)Me, -CH(Et)Et, -CH(Me)Et, -CH(Et)Pr, cyclohexyl group, cyclopentyl group, -CH(Me)CHCHOMe, -CHCHOMe, -CHCHOEt, -CHCHOPr, -CHCHCHOH, -CHCHCHOMe, -CHCHCHOEt, -CHCHCHOPr or -CHCHOH, R of the chemical formula (1) 3is -Me, -Et, -Pr, -CH(Me)Me, -CH(Et)Et, -CH(Me)Et, -CH(Et)Pr, cyclohexyl group, cyclopentyl group, -CH(Me)CHCHOMe, -CHCHOMe, -CHCHOEt, -CHCHOPr, -CHCHCHOH, -CHCHCHOMe, -CHCHCHOEt, -CHCHCHOPr or -CHCHOH, R of the above chemical formula (2) 4 -CH2CH2-, -CH2CH2CH2-, -CH2CH2CH2CH2-, -CH2CH2CH2CH2CH2-, -CH2CH2CH2CH2CH2CH2-, -(CH2CH2NH) s -(CH2CH2) t -(s is 1 to 3, t is 1), -(CH2CH2CH2NH) x -(CH2CH2CH2) y -(x is 1 or 2, y is 1), -CH2CH2CH2OCH2CH2CH2-, -CH2CH2OCH2CH2-, -CH2CH(Me)CH2-, -CH2C(Me)2CH2-, -C(Me)2C(Me)2-, or the cyclic alkyl chain -(CH4)-; R of the above chemical formula (2) 5 is -Me, -Et, -Pr, -CH(Me)Me, -CH(Et)Et, -CH(Me)Et, cyclohexyl, cyclopentyl, -CH(Me)CHCHOMe, -CHCHOMe, -CHCHOEt, -CHCHOPr, -CHCHCHOH, -CHCHCHOMe, -CHCHCHOEt, -CHCHCHOPr or -CHCHOH; R of the above chemical formula (2) 6 -Me, -Et, -Pr, -CH(Me)Me, -CH(Et)Et, -CH(Me)Et, -CH(Et)Pr, -C6H 11 , a cyclopentyl group, -CH(Me)CH2CH2OMe, -CH2CH2OMe, -CH2CH2OEt, -CH2CH2OPr, -CH2CH2CH2OH, -CH2CH2CH2OMe, -CH2CH2CH2OEt, -CH2CH2CH2OPr, or -CH2CH2OH, R of the above chemical formula (2) 7 A water treatment system according to any one of technical proposals 1 to 6, wherein is -Me, -Et, or -Pr. Technical proposal 8 R of the chemical formula (1) 1 is -CH2CH2-, -CH2CH2CH2-, -CH2CH2CH2CH2-, -CH2CH2CH2CH2CH2- or -CH2CH2CH2CH2CH2CH2CH2-, R of the chemical formula (1) 2 is -Me, -Et, -CH(Me)Me, -CH(Et)Et, -CH(Me)Et, -CH(Et)Pr, a cyclohexyl group, or a cyclopentyl group, R of the chemical formula (1) 3 is -Me, -Et, -CH(Me)Me, -CH(Et)Et, -CH(Me)Et, -CH(Et)Pr, a cyclohexyl group, or a cyclopentyl group, R of the above chemical formula (2) 4 is -CH2CH2-, -CH2CH2CH2-, -CH2CH2CH2CH2-, -CH2CH2CH2CH2CH2- or -CH2CH2CH2CH2CH2CH2CH2-, R of the above chemical formula (2) 5 is -Me, -Et, -CH(Me)Me, -CH(Et)Et, -CH(Me)Et, -CH(Et)Pr, a cyclohexyl group, or a cyclopentyl group, R of the above chemical formula (2) 6 is -Me, -Et, -CH(Me)Me, -CH(Et)Et, -CH(Me)Et, -CH(Et)Pr, a cyclohexyl group, or a cyclopentyl group, R of the above chemical formula (2) 7 A water treatment system according to any one of technical proposals 1 to 7, wherein is -Me or -Et. Technical proposal 9 R of the chemical formula (1) 1 is -CH2CH2-, -CH2CH2CH2-, -CH2CH2CH2CH2-, -CH2CH2CH2CH2CH2- or -CH2CH2CH2CH2CH2CH2CH2-, R of the chemical formula (1) 2 is -Me, -Et, -CH(Me)Me, -CH(Et)Et, -CH(Me)Et, or -CH(Et)Pr, R of the chemical formula (1) 3 is -CH(Me)Me, -CH(Et)Et, -CH(Me)Et, or -CH(Et)Pr, R of the above chemical formula (2) 4 is -CH2CH2-, -CH2CH2CH2-, -CH2CH2CH2CH2-, -CH2CH2CH2CH2CH2- or -CH2CH2CH2CH2CH2CH2CH2-, R of the above chemical formula (2) 5 is -Me, -Et, -CH(Me)Me, -CH(Et)Et, -CH(Me)Et, or -CH(Et)Pr, R of the above chemical formula (2) 6 is -Me, -Et, -CH(Me)Me, -CH(Et)Et, -CH(Me)Et, or -CH(Et)Pr, R of the above chemical formula (2) 7 A water treatment system according to any one of technical proposals 1 to 8, wherein is -Me or -Et. Technical proposal 10 R of the above chemical formula (2) 4 is -CH2CH2-, -CH2CH2CH2-, -CH2CH2CH2CH2-, -CH2CH2CH2CH2CH2- or -CH2CH2CH2CH2CH2CH2CH2-, R of the above chemical formula (2) 5 is -Me, -Et, -CH(Me)Me, -CH(Et)Et, -CH(Me)Et, or -CH(Et)Pr, R of the above chemical formula (2) 6 is -Me, -Et or -CH(Me)Me, R of the above chemical formula (2) 7 A water treatment system according to any one of technical proposals 1 to 9, wherein is -Me or -Et. Technical proposal 11 R of the chemical formula (1) 1 is -CH2CH2- or -CH2CH2CH2-, R of the chemical formula (1) 2 is -Me, -Et, -CH(Me)Me, -CH(Et)Et, -CH(Me)Et, or -CH(Et)Pr, R of the chemical formula (1) 3 is -CH(Me)Me, -CH(Et)Et, -CH(Me)Et, or -CH(Et)Pr, R of the above chemical formula (2) 4 is -CH2CH2- or -CH2CH2CH2-, R of the above chemical formula (2) 5 is -Me, -Et, -CH(Me)Me, -CH(Et)Et, -CH(Me)Et, or -CH(Et)Pr, R of the above chemical formula (2) 6 is -Me, -Et, -CH(Me)Me, -CH(Et)Et, -CH(Me)Et, or -CH(Et)Pr, R of the above chemical formula (2) 7 A water treatment system according to any one of technical proposals 1 to 10, wherein is -Me or -Et. Technical proposal 12 The water treatment system according to any one of Technical Schemes 1 to 11, wherein R2 and R3 in the chemical formula (1) are the same. Technical proposal 13 The water treatment system according to any one of Technical Schemes 1 to 11, wherein R2 and R3 in the chemical formula (1) are different. Technical proposal 14 R of the amine compound of the chemical formula (2) 6 and R 7 A water treatment system according to any one of technical proposals 1 to 13, wherein the above is the same. Technical proposal 15 R of the amine compound of the chemical formula (2) 6 and R 7 14. The water treatment system according to any one of technical proposals 1 to 13, wherein: Technical proposal 16 R of the amine compound of the chemical formula (2) 5 , R 6 and R 7A water treatment system according to any one of technical proposals 1 to 13, in which two or three of the above are the same. Technical proposal 17 R of the amine compound of the chemical formula (2) 5 , R 6 and R 7 14. A water treatment system according to any one of technical proposals 1 to 13, wherein all of the above are different. Technical proposal 18 R of the amine compound of the chemical formula (2) 5 R 6 and / or R 7 A water treatment system according to any one of technical proposals 1 to 13, which is different from the above. Technical proposal 19 The water treatment system according to Technical Scheme 1, wherein the amine solution contains 80 wt% or more and 100 wt% or less of an amine compound represented by the chemical formula (1) and / or the chemical formula (2). Technical proposal 20 A water treatment system according to any one of technical proposals 1 to 19, wherein the first mixture undergoes phase separation at a temperature between 3°C and 40°C. Technical proposal 21 In the chemical formula (1), the ratio of the number of carbon atoms in the molecule to the number of nitrogen atoms in the molecule is 4.0 or more and 6.0 or less, A water treatment system according to any one of Technical Schemes 1 to 20, wherein in the chemical formula (2), [number of carbon atoms in the molecule] / [number of nitrogen atoms in the molecule] is 4.0 or more and 6.0 or less. Technical proposal 22 R of the chemical formula (1) 1 The linear alkyl chain has 2 or 3 carbon atoms, R of the above chemical formula (2) 4 22. A water treatment system according to any one of Technical Schemes 1 to 21, wherein the number of carbon atoms in the linear alkyl chain is 2 or 3. Technical proposal 23 In the chemical formula (1), the number of nitrogen atoms contained in the molecule is 2 or more and 5 or less, The water treatment system according to any one of Technical Schemes 1 to 22, wherein the number of nitrogen atoms contained in the molecule in the chemical formula (2) is 2 or more and 5 or less. Technical proposal 24 A water treatment system according to any one of Technical Schemes 1 to 23, wherein the total number of moles of the amine compounds of the chemical formula (1) and / or the chemical formula (2) in the amine solution is equal to or greater than the total number of moles of inorganic salts and / or organic substances contained in the water to be treated. Technical proposal 25 A water treatment system according to any one of Technical Schemes 1 to 24, wherein the total number of moles of the amine compounds of the chemical formula (1) and / or the chemical formula (2) in the amine solution is at least twice the total number of moles of inorganic salts and / or organic substances contained in the water to be treated. Technical proposal 26 A water treatment system according to any one of Technical Schemes 1 to 25, wherein the total number of moles of the amine compounds of the chemical formula (1) and / or the chemical formula (2) in the amine solution is 5 times or more the total number of moles of inorganic salts and / or organic substances contained in the water to be treated. Technical proposal 27 a step of mixing the water to be treated and the amine solution to obtain a first mixture; phase-separating the first mixture to obtain a phase-separated second mixture; separating the supernatant and concentrated phases of the phase-separated second mixture; The water treatment method according to any one of Technical Schemes 1 to 23, wherein the amine solution contains the amine compound of formula (1) and / or formula (2). Technical proposal 28 A water treatment method according to Technical Proposal 27, wherein the first mixture undergoes phase separation at a temperature between 3°C and 40°C. Technical proposal 29 The method further comprises a means for separating the supernatant phase into an aqueous phase and an organic phase to separate and recover the amine, The water treatment system according to any one of Technical Schemes 1 to 26, wherein the supernatant phase separates into an aqueous phase and an organic phase at a temperature higher than that at which the first mixture phase separates. Technical proposal 30 The water treatment system according to Technical Proposal 29, wherein the supernatant phase separates into an aqueous phase and an organic phase at a temperature of 35°C or higher and 90°C or lower. Technical proposal 31 The method further comprises a step of heating the supernatant phase to separate it into an aqueous phase and an organic phase, and separating and recovering the amine compound; The water treatment method according to Technical Scheme 27 or 28, wherein the supernatant phase separates into an aqueous phase and an organic phase at a temperature higher than that at which the first mixture phase separates. Technical proposal 32 The water treatment method according to Technical Scheme 31, wherein the supernatant phase separates into an aqueous phase and an organic phase at a temperature of 35°C or higher and 90°C or lower. Technical proposal 33 The thermoresponsive amine compound is represented by the chemical formula (1) or / and the chemical formula (2), R of the chemical formula (1) 1 is a linear alkyl chain having 2 to 6 carbon atoms, a branched alkyl chain having 4 to 6 carbon atoms, a cyclic alkyl chain having 5 or 6 carbon atoms, an ether chain having 2 to 6 carbon atoms, or an amino alkyl chain having 2 to 9 carbon atoms, R of the chemical formula (1) 2 is a hydrocarbon group having 1 to 6 carbon atoms, R of the chemical formula (1) 3 is a hydrocarbon group having 1 to 6 carbon atoms, In the chemical formula (1), the ratio of the number of carbon atoms in the molecule to the number of nitrogen atoms in the molecule is 4.0 or more and 7.0 or less, R of the above chemical formula (2) 4 is a linear alkyl chain having 2 to 6 carbon atoms, a branched alkyl chain having 4 to 6 carbon atoms, a cyclic alkyl chain having 5 or 6 carbon atoms, an ether chain having 2 to 6 carbon atoms, or an amino alkyl chain having 2 to 9 carbon atoms, R of the above chemical formula (2) 5 is a hydrocarbon group having 1 to 6 carbon atoms, R of the above chemical formula (2) 6 is a hydrocarbon group having 1 to 6 carbon atoms, R of the above chemical formula (2) 7 is a hydrocarbon group having 1 to 6 carbon atoms, In the chemical formula (2), the ratio of the number of carbon atoms in the molecule to the number of nitrogen atoms in the molecule is 4.0 or more and 7.0 or less, the lower critical solution temperature of the amine compound of the chemical formula (2) is in the range of 35°C or more and 90°C or less; The lower critical solution temperature of the amine compound of the chemical formula (2) is in the range of 35°C to 90°C. Technical proposal 34 The vapor pressure of the amine compound of the chemical formula (1) at 25°C under atmospheric pressure is 1.0 x 10 -10 [Torr] or more and 5.0 [Torr] or less, The vapor pressure of the amine compound of the chemical formula (2) at 25°C under atmospheric pressure is 1.0 x 10 -10 The amine solution according to Technical Proposal 33, wherein the pressure is not less than 5.0 [Torr] and not more than 5.0 [Torr]. Technical proposal 35 The vapor pressure of the amine compound of the chemical formula (1) at 25°C under atmospheric pressure is 1.0 x 10 -10 Torr or more and 3.0 Torr or less, The vapor pressure of the amine compound of the chemical formula (2) at 25°C under atmospheric pressure is 1.0 x 10 -10 The amine solution according to Technical Scheme 33 or 34, wherein the pressure is 3.0 Torr or more and 3.0 Torr or less. Technical proposal 36 The vapor pressure of the amine compound of the chemical formula (1) at 25°C under atmospheric pressure is 1.0 x 10 -10 Torr or more and 1.0 Torr or less, The vapor pressure of the amine compound of the chemical formula (2) at 25°C under atmospheric pressure is 1.0 x 10 -10 The amine solution according to any one of Technical Schemes 33 to 35, wherein the pressure is from 1.0 [Torr] to 1.0 [Torr]. The requirements for amine compounds described in any one of Technical Schemes 2 to 23 are applicable to the amine solution technical schemes of Technical Schemes 33 to 36. [Explanation of symbols]

[0139] 11: Means for introducing the water to be treated A into the first container B 12: Means for introducing amine solution C into first container B to obtain first mixture D 13: Temperature control means for controlling the temperature 14: Means for separating a supernatant phase F and a concentrated phase G of a second mixture E obtained by phase separation of a first mixture D containing the water to be treated A and an amine solution C. 15: Means for separating the supernatant phase F into an aqueous phase H and an organic phase J to separate and recover the amine compound (organic phase J) 16: Means for treating aqueous phase H with RO membrane (reverse osmosis membrane) 20: Filter 100: Water treatment system 200: Water treatment system 300: Water treatment system A: Water to be treated B: 1st container C: Amine solution D: 1st mixture E: Second mixture F: Supernatant phase G: Concentrated phase H: water phase J:Organic phase L: Concentrated water M: Water

Claims

1. a means for introducing water to be treated into the first container; means for introducing an amine solution into said first vessel to provide a first mixture; a means for separating the supernatant phase and the concentrated phase of the second mixture obtained by phase separation of the first mixture; The amine solution contains an amine compound represented by chemical formula (1) or / and chemical formula (2), R of the chemical formula (1) １ is a linear alkyl chain having 2 to 6 carbon atoms, a branched alkyl chain having 4 to 6 carbon atoms, a cyclic alkyl chain having 5 or 6 carbon atoms, an ether chain having 2 to 6 carbon atoms, or an aminoalkyl chain having 2 to 9 carbon atoms, R of the chemical formula (1) ２ is a hydrocarbon group having 1 to 6 carbon atoms, R of the chemical formula (1) ３ is a hydrocarbon group having 1 to 6 carbon atoms, In the chemical formula (1), [the number of carbon atoms in the molecule] / [the number of nitrogen atoms in the molecule] is 4.0 or more and 7.0 or less, R of the above chemical formula (2) ４ is a linear alkyl chain having 2 to 6 carbon atoms, a branched alkyl chain having 4 to 6 carbon atoms, a cyclic alkyl chain having 5 or 6 carbon atoms, an ether chain having 2 to 6 carbon atoms, or an aminoalkyl chain having 2 to 9 carbon atoms, R of the above chemical formula (2) ５ is a hydrocarbon group having 1 to 6 carbon atoms, R of the above chemical formula (2) ６ is a hydrocarbon group having 1 to 6 carbon atoms, R of the above chemical formula (2) ７ is a hydrocarbon group having 1 to 6 carbon atoms, A water treatment system, wherein in the chemical formula (2), [number of carbon atoms in the molecule] / [number of nitrogen atoms in the molecule] is 4.0 or more and 7.0 or less. 【Chemical 1】

2. R of the chemical formula (1) １ is a linear alkyl chain having 2 to 6 carbon atoms, a branched alkyl chain having 4 to 6 carbon atoms, or a cyclic alkyl chain having 5 or 6 carbon atoms, and the cyclic alkyl chain is unsubstituted and the first carbon atom of the cyclic alkyl chain is R ２ The carbon atom at the second position of the cyclic alkyl chain is bonded to the nitrogen atom bonded to R ３ a cyclic alkyl chain, a linear ether chain having 2 to 6 carbon atoms, or a linear aminoalkyl chain having 2 to 9 carbon atoms, bonded to the nitrogen bonded to R of the chemical formula (1) ２ is a hydrocarbon group having 1 to 6 carbon atoms and consisting of carbon and hydrogen, or a hydrocarbon group having 1 to 6 carbon atoms and consisting of carbon, hydrogen, and oxygen, R of the chemical formula (1) ３ is a hydrocarbon group having 1 to 6 carbon atoms and consisting of carbon and hydrogen, or a hydrocarbon group having 1 to 6 carbon atoms and consisting of carbon, hydrogen, and oxygen, R of the above chemical formula (2) ４ is a linear alkyl chain having 2 to 6 carbon atoms, a branched alkyl chain having 4 to 6 carbon atoms, or a cyclic alkyl chain having 5 or 6 carbon atoms, and the cyclic alkyl chain is unsubstituted and the first carbon atom of the cyclic alkyl chain is R ２ The carbon atom at the second position of the cyclic alkyl chain is bonded to the nitrogen atom bonded to R ３ a cyclic alkyl chain bonded to the nitrogen bonded to the alkyl group, a cyclic alkyl chain having 5 or 6 carbon atoms, a linear ether chain having 2 to 6 carbon atoms, or a linear amino alkyl chain having 2 to 9 carbon atoms; R of the above chemical formula (2) ５ is a hydrocarbon group having 1 to 6 carbon atoms and consisting of carbon and hydrogen, or a hydrocarbon group having 1 to 6 carbon atoms and consisting of carbon, hydrogen, and oxygen, R of the above chemical formula (2) ６ is a hydrocarbon group having 1 to 6 carbon atoms and consisting of carbon and hydrogen, or a hydrocarbon group having 1 to 6 carbon atoms and consisting of carbon, hydrogen, and oxygen, R of the above chemical formula (2) ７ The water treatment system according to claim 1, wherein is a hydrocarbon group having 1 to 6 carbon atoms and consisting of carbon and hydrogen, or a hydrocarbon group having 1 to 6 carbon atoms and consisting of carbon, hydrogen, and oxygen.

3. R of the chemical formula (1) １ is a linear alkyl chain having 2 to 6 carbon atoms, a branched alkyl chain having 4 to 6 carbon atoms, or a cyclic alkyl chain having 5 or 6 carbon atoms, and the cyclic alkyl chain is unsubstituted and the first carbon atom of the cyclic alkyl chain is R ２ The carbon atom at the second position of the cyclic alkyl chain is bonded to the nitrogen atom bonded to R ３ a linear ether chain having 2 to 6 carbon atoms and an alkyl chain having 2 or 3 carbon atoms bonded to oxygen, or a linear aminoalkyl chain having 2 to 9 carbon atoms, wherein the amino group contained in the aminoalkyl chain is secondary, the number of amino groups contained in the aminoalkyl chain is 1 to 3, and the linear alkyl chain having 2 or 3 carbon atoms is bonded to the amino group of the aminoalkyl chain; R of the chemical formula (1) ２ is a saturated hydrocarbon group having 1 to 6 carbon atoms and consisting of carbon and hydrogen, or a saturated hydrocarbon group having 1 to 6 carbon atoms and consisting of carbon, hydrogen, and oxygen, R of the chemical formula (1) ３ is a saturated hydrocarbon group having 1 to 6 carbon atoms and consisting of carbon and hydrogen, or a saturated hydrocarbon group having 1 to 6 carbon atoms and consisting of carbon, hydrogen, and oxygen, R of the above chemical formula (2) ４ is a linear alkyl chain having 2 to 6 carbon atoms, a branched alkyl chain having 4 to 6 carbon atoms, or a cyclic alkyl chain having 5 or 6 carbon atoms, and the cyclic alkyl chain is unsubstituted and the first carbon atom of the cyclic alkyl chain is R ２ The carbon atom at the second position of the cyclic alkyl chain is bonded to the nitrogen atom bonded to R ３ a cyclic alkyl chain bonded to a nitrogen atom bonded to the oxygen atom, a cyclic alkyl chain having 5 or 6 carbon atoms, a linear ether chain having 2 to 6 carbon atoms, and an alkyl chain having 2 or 3 carbon atoms bonded to the oxygen atom, or a linear aminoalkyl chain having 2 to 9 carbon atoms, wherein the amino group contained in the aminoalkyl chain is secondary, the number of amino groups contained in the aminoalkyl chain is 1 to 3, and the linear alkyl chain having 2 or 3 carbon atoms is bonded to the amino group of the aminoalkyl chain, R of the above chemical formula (2) ５ is a saturated hydrocarbon group having 1 to 6 carbon atoms and consisting of carbon and hydrogen, or a saturated hydrocarbon group having 1 to 6 carbon atoms and consisting of carbon, hydrogen, and oxygen, R of the above chemical formula (2) ６ is a saturated hydrocarbon group having 1 to 6 carbon atoms and consisting of carbon and hydrogen, or a saturated hydrocarbon group having 1 to 6 carbon atoms and consisting of carbon, hydrogen, and oxygen, R of the above chemical formula (2) ７ The water treatment system according to claim 1, wherein is a saturated hydrocarbon group having 1 to 6 carbon atoms and consisting of carbon and hydrogen, or a saturated hydrocarbon group having 1 to 6 carbon atoms and consisting of carbon, hydrogen, and oxygen.

4. R of the chemical formula (1) １ is a linear alkyl chain having 2 to 6 carbon atoms, a branched alkyl chain having 4 to 6 carbon atoms, or a cyclic alkyl chain having 5 or 6 carbon atoms, and the cyclic alkyl chain is unsubstituted and the first carbon atom of the cyclic alkyl chain is R ２ The carbon atom at the second position of the cyclic alkyl chain is bonded to the nitrogen atom bonded to R ３ a linear ether chain having 2 to 6 carbon atoms and an alkyl chain having 2 or 3 carbon atoms bonded to oxygen, or a linear aminoalkyl chain having 2 to 9 carbon atoms, wherein the amino group contained in the aminoalkyl chain is secondary and the number of amino groups contained in the aminoalkyl chain is 1 to 3, and wherein the linear alkyl chain having 2 or 3 carbon atoms is bonded to the amino group of the aminoalkyl chain; R of the chemical formula (1) ２ is a saturated hydrocarbon group having 1 to 6 carbon atoms and consisting of carbon and hydrogen, R of the chemical formula (1) ３ is a saturated hydrocarbon group having 1 to 6 carbon atoms and consisting of carbon and hydrogen, or an ether group or alcohol group having 1 to 6 carbon atoms and consisting of carbon, hydrogen, and oxygen, R of the above chemical formula (2) ４ is a linear alkyl chain having 2 to 6 carbon atoms, a branched alkyl chain having 4 to 6 carbon atoms, or a cyclic alkyl chain having 5 or 6 carbon atoms, wherein the cyclic alkyl chain is unsubstituted and the carbon at position 1 of the cyclic alkyl chain is bonded to the nitrogen bonded to R2 and the carbon at position 2 of the cyclic alkyl chain is bonded to the nitrogen bonded to R3, a cyclic alkyl chain having 5 or 6 carbon atoms, a linear ether chain having 2 to 6 carbon atoms, in which an alkyl chain having 2 or 3 carbon atoms is bonded to oxygen, or a linear aminoalkyl chain having 2 to 9 carbon atoms, in which the amino group contained in the aminoalkyl chain is secondary and the number of amino groups contained in the aminoalkyl chain is 1 to 3, and the linear alkyl chain having 2 or 3 carbon atoms is bonded to the amino group of the aminoalkyl chain, R of the above chemical formula (2) ５ is a saturated hydrocarbon group having 1 to 6 carbon atoms and consisting of carbon and hydrogen, or an ether group or alcohol group having 1 to 6 carbon atoms and consisting of carbon, hydrogen, and oxygen, R of the above chemical formula (2) ６ is a saturated hydrocarbon group having 1 to 6 carbon atoms and consisting of carbon and hydrogen, or an ether group or alcohol group having 1 to 6 carbon atoms and consisting of carbon, hydrogen, and oxygen, R of the above chemical formula (2) ７ 2. The water treatment system according to claim 1, wherein is a saturated hydrocarbon group having 1 to 6 carbon atoms and consisting of carbon and hydrogen.

5. R of the chemical formula (1) １ is -CH ２ CH ２ -, -CH ２ CH ２ CH ２ -, -CH ２ CH ２ CH ２ CH ２ -, -CH ２ CH ２ CH ２ CH ２ CH ２ -, -CH ２ CH ２ CH ２ CH ２ CH ２ CH ２ -, -(CH ２ CH ２ NH) ｎ - (CH ２ CH ２ ) ｍ -(n is 1 to 3, m is 1), -(CH ２ CH ２ CH ２ NH) ｐ - (CH ２ CH ２ CH ２ ) ｑ -(p is 1 or 2, q is 1), -CH ２ CH ２ CH ２ OCH ２ CH ２ CH ２ -, -CH ２ CH ２ OCH ２ CH ２ -, -CH ２ CH(Me)CH ２ -, -CH ２ C (Me) ２ CH ２ -, -C(Me) ２ C (Me) ２ - or a cyclic alkyl chain -(C ６ H ４ ) - and R of the chemical formula (1) ２ is -Me, -Et, -Pr, -CH(Me)Me, -CH(Et)Et, -CH(Me)Et, -CH(Et)Pr, cyclohexyl group, cyclopentyl group, -CH(Me)CH ２ CH ２ OMe, -CH ２ CH ２ OMe, -CH ２ CH ２ OEt, -CH ２ CH ２ OPr, -CH ２ CH ２ CH ２ OH, -CH ２ CH ２ CH ２ OMe, -CH ２ CH ２ CH ２ OEt, -CH ２ CH ２ CH ２ OPr or -CH ２ CH ２ OH, R of the chemical formula (1) ３ is -Me, -Et, -Pr, -CH(Me)Me, -CH(Et)Et, -CH(Me)Et, -CH(Et)Pr, cyclohexyl group, cyclopentyl group, -CH(Me)CH ２ CH ２ OMe, -CH ２ CH ２ OMe, -CH ２ CH ２ OEt, -CH ２ CH ２ OPr, -CH ２ CH ２ CH ２ OH, -CH ２ CH ２ CH ２ OMe, -CH ２ CH ２ CH ２ OEt, -CH ２ CH ２ CH ２ OPr or -CH ２ CH ２ OH, R of the above chemical formula (2) ４ is -CH ２ CH ２ -, -CH ２ CH ２ CH ２ -, -CH ２ CH ２ CH ２ CH ２ -, -CH ２ CH ２ CH ２ CH ２ CH ２ -, -CH ２ CH ２ CH ２ CH ２ CH ２ CH ２ -, -(CH ２ CH ２ NH) ｓ - (CH ２ CH ２ ) ｔ -(s is 1 to 3, t is 1), -(CH ２ CH ２ CH ２ NH) ｘ - (CH ２ CH ２ CH ２ ) ｙ -(x is 1 or 2, y is 1), -CH ２ CH ２ CH ２ OCH ２ CH ２ CH ２ -, -CH ２ CH ２ OCH ２ CH ２ -, -CH ２ CH(Me)CH ２ -, -CH ２ C (Me) ２ CH ２ -, -C(Me) ２ C (Me) ２ - or a cyclic alkyl chain -(C ６ H ４ ) - and R of the above chemical formula (2) ５ is -Me, -Et, -Pr, -CH(Me)Me, -CH(Et)Et, -CH(Me)Et, cyclohexyl group, cyclopentyl group, -CH(Me)CH ２ CH ２ OMe, -CH ２ CH ２ OMe, -CH ２ CH ２ OEt, -CH ２ CH ２ OPr, -CH ２ CH ２ CH ２ OH, -CH ２ CH ２ CH ２ OMe, -CH ２ CH ２ CH ２ OEt, -CH ２ CH ２ CH ２ OPr or -CH ２ CH ２ OH, R of the above chemical formula (2) ６ -Me, -Et, -Pr, -CH(Me)Me, -CH(Et)Et, -CH(Me)Et, -CH(Et)Pr, -C ６ H １１ , cyclopentyl group, —CH(Me)CH ２ CH ２ OMe, -CH ２ CH ２ OMe, -CH ２ CH ２ OEt, -CH ２ CH ２ OPr, -CH ２ CH ２ CH ２ OH, -CH ２ CH ２ CH ２ OMe, -CH ２ CH ２ CH ２ OEt, -CH ２ CH ２ CH ２ OPr or -CH ２ CH ２ OH, R of the above chemical formula (2) ７ The water treatment system according to claim 1, wherein is -Me, -Et, or -Pr.

6. R of the chemical formula (1) １ is -CH ２ CH ２ -, -CH ２ CH ２ CH ２ -, -CH ２ CH ２ CH ２ CH ２ -, -CH ２ CH ２ CH ２ CH ２ CH ２ - or -CH ２ CH ２ CH ２ CH ２ CH ２ CH ２ - and R of the chemical formula (1) ２ is -Me, -Et, -CH(Me)Me, -CH(Et)Et, -CH(Me)Et, -CH(Et)Pr, a cyclohexyl group, or a cyclopentyl group, R of the chemical formula (1) ３ is -Me, -Et, -CH(Me)Me, -CH(Et)Et, -CH(Me)Et, -CH(Et)Pr, a cyclohexyl group, or a cyclopentyl group, R of the above chemical formula (2) ４ is -CH ２ CH ２ -, -CH ２ CH ２ CH ２ -, -CH ２ CH ２ CH ２ CH ２ -, -CH ２ CH ２ CH ２ CH ２ CH ２ - or -CH ２ CH ２ CH ２ CH ２ CH ２ CH ２ - and R of the above chemical formula (2) ５ is -Me, -Et, -CH(Me)Me, -CH(Et)Et, -CH(Me)Et, -CH(Et)Pr, a cyclohexyl group, or a cyclopentyl group, R of the above chemical formula (2) ６ is -Me, -Et, -CH(Me)Me, -CH(Et)Et, -CH(Me)Et, -CH(Et)Pr, a cyclohexyl group, or a cyclopentyl group, R of the above chemical formula (2) ７ The water treatment system according to claim 1, wherein is -Me or -Et.

7. R of the chemical formula (1) １ is -CH ２ CH ２ -, -CH ２ CH ２ CH ２ -, -CH ２ CH ２ CH ２ CH ２ -, -CH ２ CH ２ CH ２ CH ２ CH ２ - or -CH ２ CH ２ CH ２ CH ２ CH ２ CH ２ - and R of the chemical formula (1) ２ is -Me, -Et, -CH(Me)Me, -CH(Et)Et, -CH(Me)Et, or -CH(Et)Pr; R of the chemical formula (1) ３ is —CH(Me)Me, —CH(Et)Et, —CH(Me)Et, or —CH(Et)Pr; R of the above chemical formula (2) ４ is -CH ２ CH ２ -, -CH ２ CH ２ CH ２ -, -CH ２ CH ２ CH ２ CH ２ -, -CH ２ CH ２ CH ２ CH ２ CH ２ - or -CH ２ CH ２ CH ２ CH ２ CH ２ CH ２ - and R of the above chemical formula (2) ５ is -Me, -Et, -CH(Me)Me, -CH(Et)Et, -CH(Me)Et, or -CH(Et)Pr; R of the above chemical formula (2) ６ is -Me, -Et, -CH(Me)Me, -CH(Et)Et, -CH(Me)Et, or -CH(Et)Pr; R of the above chemical formula (2) ７ The water treatment system according to claim 1, wherein is -Me or -Et.

8. 2. The water treatment system according to claim 1, wherein the amine solution contains 80 wt % to 100 wt % of the amine compound represented by the chemical formula (1) or / and the chemical formula (2).

9. The water treatment system according to claim 1 , wherein the first mixture undergoes phase separation at a temperature of 3° C. or higher and 40° C. or lower.

10. In the chemical formula (1), [the number of carbon atoms in the molecule] / [the number of nitrogen atoms in the molecule] is 4.0 or more and 6.0 or less, 2. The water treatment system according to claim 1, wherein in the chemical formula (2), [number of carbon atoms in the molecule] / [number of nitrogen atoms in the molecule] is 4.0 or more and 6.0 or less.

11. R of the chemical formula (1) １ The linear alkyl chain has 2 or 3 carbon atoms, R of the above chemical formula (2) ４ 11. The water treatment system according to claim 1, wherein the linear alkyl chain has two or three carbon atoms.

12. In the chemical formula (1), the number of nitrogen atoms contained in the molecule is 2 or more and 5 or less, 11. The water treatment system according to claim 1, wherein the number of nitrogen atoms contained in the molecule of the chemical formula (2) is 2 or more and 5 or less.

13. a step of mixing the water to be treated and the amine solution to obtain a first mixture; phase separating the first mixture to obtain a phase-separated second mixture; separating the supernatant and concentrated phases of the phase-separated second mixture; The water treatment method, wherein the amine solution contains the amine compounds of the chemical formula (1) and / or the chemical formula (2) according to any one of claims 1 to 12.

14. The water treatment method according to claim 13, wherein the first mixture undergoes phase separation at a temperature of 3°C or higher and 40°C or lower.

15. The method further comprises a means for separating the supernatant phase into an aqueous phase and an organic phase to separate and recover the amine, 2. The water treatment system of claim 1, wherein the supernatant phase separates into an aqueous phase and an organic phase at a temperature higher than that at which the first mixture phase separates.

16. The water treatment system according to claim 15, wherein the supernatant phase separates into an aqueous phase and an organic phase at a temperature of 35°C or higher and 90°C or lower.

17. The method further comprises a step of heating the supernatant phase to separate it into an aqueous phase and an organic phase, and separating and recovering the amine compound; 14. The water treatment method according to claim 13, wherein the supernatant phase separates into an aqueous phase and an organic phase at a temperature higher than that at which the first mixture phase separates.

18. The water treatment method according to claim 17, wherein the supernatant phase separates into an aqueous phase and an organic phase at a temperature of 35°C or higher and 90°C or lower.

19. The thermoresponsive amine compound is represented by the chemical formula (1) or / and the chemical formula (2), R of the chemical formula (1) １ is a linear alkyl chain having 2 to 6 carbon atoms, a branched alkyl chain having 4 to 6 carbon atoms, a cyclic alkyl chain having 5 or 6 carbon atoms, an ether chain having 2 to 6 carbon atoms, or an aminoalkyl chain having 2 to 9 carbon atoms, R of the chemical formula (1) ２ is a hydrocarbon group having 1 to 6 carbon atoms, R of the chemical formula (1) ３ is a hydrocarbon group having 1 to 6 carbon atoms, In the chemical formula (1), [the number of carbon atoms in the molecule] / [the number of nitrogen atoms in the molecule] is 4.0 or more and 7.0 or less, R of the above chemical formula (2) ４ is a linear alkyl chain having 2 to 6 carbon atoms, a branched alkyl chain having 4 to 6 carbon atoms, a cyclic alkyl chain having 5 or 6 carbon atoms, an ether chain having 2 to 6 carbon atoms, or an aminoalkyl chain having 2 to 9 carbon atoms, R of the above chemical formula (2) ５ is a hydrocarbon group having 1 to 6 carbon atoms, R of the above chemical formula (2) ６ is a hydrocarbon group having 1 to 6 carbon atoms, R of the above chemical formula (2) ７ is a hydrocarbon group having 1 to 6 carbon atoms, In the chemical formula (2), [the number of carbon atoms in the molecule] / [the number of nitrogen atoms in the molecule] is 4.0 or more and 7.0 or less, the lower critical solution temperature of the amine compound of the chemical formula (2) is in the range of 35° C. or more and 90° C. or less; The amine compound of the chemical formula (2) has a lower critical solution temperature in the range of 35° C. to 90° C. 【Chemistry 2】

20. The vapor pressure of the amine compound of the chemical formula (1) at 25°C under atmospheric pressure is 1.0 x 10 －１０ [Torr] or more and 5.0 [Torr] or less, The vapor pressure of the amine compound of the chemical formula (2) at 25°C under atmospheric pressure is 1.0 x 10 －１０ 20. The amine solution according to claim 19, wherein the pressure is from 1 Torr to 5.0 Torr.

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