N-alkylated polyethylene polyamine mixture

Abstract

To provide an N-alkylated polyethylene amine mixture usable as an aqueous solution for carbon dioxide separation, which prevents the formation of N-alkylated polyethylene amine hydrates that cause solidification of the aqueous solution.SOLUTION: An N-alkylated polyethylene polyamine mixture contains both linear N-alkylated polyethylene polyamines and branched N-alkylated polyethylene polyamines. The number of nitrogen atoms contained in each of the linear and branched N-alkylated polyethylene polyamines is four or more. The content ratio of the linear N-alkylated polyethylene polyamines is 35 mass% or less relative to the total 100 mass% of the mixture.SELECTED DRAWING: None

Description

[Technical field]

[0001] The present invention relates to an N-alkylated polyethylene polyamine mixture and a method for producing the same. [Background technology]

[0002] In recent years, in order to prevent global warming, there has been a demand for reducing the amount of carbon dioxide emitted into the atmosphere. Known methods for reducing carbon dioxide include separating and recovering carbon dioxide from exhaust gases that contain carbon dioxide and are discharged from boilers that burn coal, oil, or natural gas and are installed in various manufacturing plants, and it is known to use polyethylene polyamine derivatives as carbon dioxide separation materials.

[0003] For example, Patent Document 1 describes a polyethylene polyamine derivative having excellent carbon dioxide absorption and desorption properties, in which the hydrogen atoms of the primary amino groups of a polyethylene polyamine having 3 or more nitrogen atoms are substituted with an alkyl group having 1 to 6 carbon atoms. Furthermore, the document describes a carbon dioxide absorption and desorption agent comprising an amine composition containing the polyethylene polyamine derivative and water. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2021-113182 A Summary of the Invention [Problem to be solved by the invention]

[0005] The present inventors have found that when an aqueous solution of N-alkylated polyethylene polyamine is prepared as a carbon dioxide absorbing and releasing agent and stored, crystals may precipitate in the aqueous solution and solidify. In such a case, it becomes difficult to fill or transfer the aqueous solution of N-alkylated polyethylene polyamine into carbon dioxide separation towers or recovery towers installed in various manufacturing plants, etc., and it also becomes difficult to use the aqueous solution.

[0006] In the above-mentioned state of the art, there is a demand for preventing solidification of an aqueous solution of N-alkylated polyethylenepolyamine. [Means for solving the problem]

[0007] The present inventors have intensively studied diisopropylated tetraethylenepentamine (IP-TEPA), an N-alkylated polyethylene polyamine used for carbon dioxide separation, and have found that diisopropylated tetraethylenepentamine (IP-TEPA) is a linear IP-TEPA, N-(2-isopropylaminoethyl)-N'-[2-[(2-isopropylaminoethyl)amino]ethyl]-1,2-ethanediamine (IUPAC name), a branched IP-TEPA, 1-(2-isopropylaminoethyl)-4-[2-[(2-isopropyl aminoethyl)amino]ethyl]piperazine (IUPAC name), and N,N,N'-tris(2-isopropylaminoethyl)-1,2-ethanediamine (IUPAC name). It was found that the mixture of diamine (IUPAC name) and N-(2-isopropylaminoethyl)-N'-[2-(1-piperazinyl)ethyl]-1,2-ethanediamine (IUPAC name), which is linear IP-TEPA, generates hydrate crystals when it comes into contact with water. In other words, it was clarified that the generation of hydrate crystals of linear N-alkylated polyethylenepolyamine is the cause of the solidification of the N-alkylated polyethylenepolyamine aqueous solution.

[0008] Furthermore, as a result of extensive investigations, the present inventors have discovered an N-alkylated polyethyleneamine mixture that does not generate hydrate crystals in an aqueous solution of the N-alkylated polyethyleneamine, thereby completing the present invention.

[0009] That is, the present invention provides the following [1] to [6]. [1] An N-alkylated polyethylene polyamine mixture comprising a linear N-alkylated polyethylene polyamine and a branched N-alkylated polyethylene polyamine, the number of nitrogen atoms contained in each of the linear N-alkylated polyethylene polyamine and the branched N-alkylated polyethylene polyamine is 4 or more, The content of linear N-alkylated polyethylene polyamine is 35% by mass or less based on the total amount of the mixture (100% by mass). N-alkylated polyethylene polyamine mixture. [2] The number of nitrogen atoms contained in each of the linear N-alkylated polyethylene polyamine and the branched N-alkylated polyethylene polyamine is 4 to 6, [1] The N-alkylated polyethylene polyamine mixture. [3] The N-alkylated polyethylenepolyamine mixture according to [1], wherein the alkyl groups contained in the linear N-alkylated polyethylenepolyamine and the branched N-alkylated polyethylenepolyamine are alkyl groups having 3 or more carbon atoms. [4] The N-alkylated polyethylene polyamine mixture according to [3], wherein the alkyl group is an isopropyl group or a cyclohexyl group. [5] The N-alkylated polyethylene polyamine mixture according to [3], wherein the alkyl group is an isopropyl group. [6] A method for producing the N-alkylated polyethylene polyamine mixture according to [1], comprising the following steps 1 to 4: (Step 1) Synthesizing an N-alkylated polyethylene polyamine mixture from a polyethylene polyamine mixture (Step 2) Mixing the N-alkylated polyethylenepolyamine mixture with water to crystallize linear N-alkylated polyethylenepolyamine hydrate (Step 3) filtering the linear N-alkylated polyethylene polyamine hydrate and separating the hydrate crystals from the filtrate. (Step 4) Concentrating the filtrate to obtain an N-alkylated polyethylene polyamine mixture. Effect of the Invention

[0010] According to the present invention, it is possible to provide an N-alkylated polyethyleneamine mixture that can be used as an aqueous solution for separating carbon dioxide, and that does not produce hydrate crystals of N-alkylated polyethyleneamine that would cause the aqueous solution to solidify. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] The present invention will be specifically described below. The present invention relates to an N-alkylated polyethylenepolyamine mixture containing a linear N-alkylated polyethylenepolyamine and a branched N-alkylated polyethylenepolyamine.

[0012] A linear N-alkylated polyethylenepolyamine is an N-alkylated polyethylenepolyamine that contains only a structure in which one or two carbon atoms are directly bonded to a nitrogen atom, and does not contain a structure in which three carbon atoms are directly bonded to a nitrogen atom.

[0013] The number of nitrogen atoms contained in the linear N-alkylated polyethylene polyamine is 4 or more, and preferably 4 or more and 6 or less.

[0014] A specific example of the linear N-alkylated polyethylene polyamine is a linear N-alkylated polyethylene polyamine represented by the following formula (1).

[0015] [ka]

[0016] In formula (1), p represents an integer of 2 to 4, and R represents an alkyl group having 3 or more carbon atoms.

[0017] The alkyl group contained in the linear N-alkylated polyethylene polyamine is preferably an alkyl group having 3 or more carbon atoms, and more preferably an alkyl group having 3 or more and 6 or less carbon atoms.

[0018] Specific examples of the alkyl group having 3 or more carbon atoms contained in the linear N-alkylated polyethylene polyamine include a propyl group, an isopropyl group, a butyl group, an isobutyl group, a pentyl group, a cyclopentyl group, a hexyl group, and a cyclohexyl group. An isopropyl group or a cyclohexyl group is preferable. An isopropyl group is more preferable.

[0019] Specific examples of the linear N-alkylated polyethylene polyamine represented by formula (1) include polyethylene polyamines represented by the following formulas (1a) to (1d).

[0020] [ka]

[0021] [ka]

[0022] [ka]

[0023] [ka]

[0024] The branched N-alkylated polyethylene polyamine is an N-alkylated polyethylene polyamine that contains at least one structure in which three carbon atoms are directly bonded to a nitrogen atom.

[0025] The number of nitrogen atoms contained in the branched N-alkylated polyethylene polyamine is 4 or more, and preferably 4 or more and 6 or less.

[0026] Specific examples of the branched N-alkylated polyethylene polyamine include branched N-alkylated polyethylene polyamines represented by the following formula (2) or formula (3).

[0027] [ka]

[0028] In formula (2), q represents an integer of 0 to 2, R represents an alkyl group having 3 or more carbon atoms, and A represents the following formula (2a) or the following formula (2b).

[0029] [ka]

[0030] [ka]

[0031] [ka]

[0032] In formula (3), r represents an integer of 1 to 3, and R represents an alkyl group having 3 or more carbon atoms.

[0033] The alkyl group contained in the branched N-alkylated polyethylene polyamine is preferably an alkyl group having 3 or more carbon atoms, and more preferably an alkyl group having 3 or more and 6 or less carbon atoms.

[0034] Specific examples of the alkyl group having 3 or more carbon atoms contained in the branched N-alkylated polyethylene polyamine include a propyl group, an isopropyl group, a butyl group, an isobutyl group, a pentyl group, a cyclopentyl group, a hexyl group, and a cyclohexyl group. An isopropyl group or a cyclohexyl group is preferable. An isopropyl group is more preferable.

[0035] Specific examples of the branched N-alkylated polyethylene polyamine represented by formula (2) include polyethylene polyamines represented by the following formulas (2c) to (2j).

[0036] [ka]

[0037] [ka]

[0038] [ka]

[0039] [ka]

[0040] [ka]

[0041] [ka]

[0042] [ka]

[0043] [ka]

[0044] Specific examples of the branched N-alkylated polyethylene polyamine represented by formula (3) include polyethylene polyamines represented by the following formulas (3a) to (3d).

[0045] [ka]

[0046] [ka]

[0047] [ka]

[0048] [ka]

[0049] The content of linear N-alkylated polyethylene polyamine contained in the N-alkylated polyethylene polyamine mixture containing linear N-alkylated polyethylene polyamine and branched N-alkylated polyethylene polyamine of the present invention is 35% by mass or less relative to the total amount of the mixture (100% by mass). Therefore, the content of branched N-alkylated polyethylene polyamine is 65% by mass or more. The content of linear N-alkylated polyethylene polyamine is preferably 32% by mass or less, and the content of branched N-alkylated polyethylene polyamine is preferably 68% by mass or more.

[0050] The method for producing an N-alkylated polyethylenepolyamine mixture containing a linear N-alkylated polyethylenepolyamine and a branched N-alkylated polyethylenepolyamine of the present invention is a method for producing the mixture, comprising the following steps 1 to 4. (Step 1) Synthesizing an N-alkylated polyethylene polyamine mixture from a polyethylene polyamine mixture (Step 2) Mixing the N-alkylated polyethylenepolyamine mixture with water to crystallize linear N-alkylated polyethylenepolyamine hydrate (Step 3) filtering the linear N-alkylated polyethylene polyamine hydrate and separating the hydrate crystals from the filtrate. (Step 4) Concentrating the filtrate to obtain an N-alkylated polyethylene polyamine mixture.

[0051] (Process 1) The polyethylene polyamine mixture used in step 1 may be a commercially available product. An example of a method for synthesizing an N-alkylated polyethylene polyamine mixture from the polyethylene polyamine mixture in step 1 is a method in which the polyethylene polyamine mixture is reacted with hydrogen and a ketone compound in the presence of a metal catalyst.

[0052] When acetone is used as the ketone compound, a mixture of N-isopropylated polyethylene polyamine compounds is synthesized, and when cyclohexanone is used, a mixture of N-cyclohexylated polyethylene polyamine compounds is synthesized.

[0053] Examples of the method for reacting a polyethylene polyamine mixture, hydrogen, and a ketone compound in the presence of a metal catalyst include a method in which hydrogen is added to the polyethylene polyamine mixture in a reaction vessel in the presence of a metal catalyst, and then a ketone compound is added to react with it, and a method in which a ketone compound is added to the polyethylene polyamine mixture in a reaction vessel, and then a metal catalyst and hydrogen are added to react with it.

[0054] Furthermore, when reacting the polyethylene polyamine mixture with hydrogen and a ketone compound in the presence of a metal catalyst, the hydrogen pressure (gauge pressure) in the reaction vessel may be 0.1 MPa or more, and the temperature in the reaction vessel may be adjusted within the range of 50°C to 200°C.

[0055] (Process 2) The method of crystallizing linear N-alkylated polyethylenepolyamine hydrate in step 2 is a method in which water is mixed with the N-alkylated polyethylenepolyamine mixture synthesized in step 1 to precipitate the N-alkylated polyethylenepolyamine as hydrate crystals.

[0056] Specifically, this method involves adding a solvent to the N-alkylated polyethylenepolyamine mixture synthesized in step 1, and then adding water while maintaining the temperature at 30°C or lower, thereby precipitating the N-alkylated polyethylenepolyamine as hydrate crystals.

[0057] (Step 3) The separation method in step 3 is a method of filtering the N-alkylated polyethylenepolyamine hydrate crystals precipitated in step 2, and is a method of separating the N-alkylated polyethylenepolyamine hydrate crystals from the filtrate by filtration.

[0058] (Step 4) Step 4 is a method for obtaining an N-alkylated polyethylenepolyamine mixture of the present invention having a linear N-alkylated polyethylenepolyamine content of 35 mass% or less, and is a method for concentrating the filtrate obtained in step 3.

[0059] The N-alkylated polyethylenepolyamine mixture of the present invention containing a linear N-alkylated polyethylenepolyamine and a branched N-alkylated polyethylenepolyamine can be used as a carbon dioxide separation material by supporting the mixture on a support such as silica. EXAMPLES

[0060] The present invention will now be described in detail with reference to examples, but the present invention is not limited to these examples.

[0061] The analysis was performed using a gas chromatograph (GC-2010 Plus) manufactured by Shimadzu Corporation, and the column used was an Rtx-5 Amine manufactured by Restek.

[0062] The abbreviations of the compounds used or synthesized in the examples are shown below. Triethylenetetramine: TETA Tetraethylenepentamine: TEPA Pentaethylenehexamine: PEHA Isopropylated triethylenetetramine: IP-TETA Isopropylated tetraethylenepentamine: IP-TEPA Isopropylated pentaethylenehexamine: IP-PEHA Cyclohexylated tetraethylenepentamine: CyHex-TEPA

[0063] The compounds used in this example are shown below. TETA used was a product of Tokyo Chemical Industry Co., Ltd. (straight-chain TETA content: 74%). The TEPA used was a product of Tosoh Corporation (linear TEPA content: 51%). The PEHA used was a Tosoh product (linear PEHA content: 28%).

[0064] Example 1 [Synthesis of IP-TEPA mixture] TEPA (330 g) and Pt / C (7 g) were placed in a 1 L pressure vessel. After replacing the inside of the reactor with nitrogen and hydrogen, hydrogen was introduced up to 2 MPa and the temperature was raised to 80°C. After reaching 80°C, hydrogen was introduced up to 4 MPa and acetone (205 g) was added dropwise. Then, the mixture was stirred for 3 hours at a hydrogen pressure of 4 MPa and an internal temperature of 80°C and cooled. The Pt / C in the reaction solution was removed by filtration, and the obtained filtrate was concentrated and purified by distillation to obtain 371 g of IP-TEPA mixture. GC analysis of the IP-TEPA mixture showed that it contained 54% linear IP-TEPA.

[0065] Example 2 [Separation of linear IP-TEPA] The IP-TEPA mixture (50 g) obtained in Example 1 and toluene (30 g) were placed in a 180 mL glass reactor. Water (12.5 g) was added dropwise while maintaining the internal temperature at about 20°C, and the mixture was stirred for 30 minutes. The precipitated crystals and the filtrate were then separated by filtration, and the filtrate was concentrated to remove the solvent. As a result, 33.5 g of crystals and 27.9 g of concentrated residue were obtained. GC analysis of the crystals and concentrated residue revealed that linear IP-TEPA was contained in 98% and 16%, respectively, in terms of GC area ratio.

[0066] Example 3 [Synthesis of IP-TETA mixture] TETA (50 g) was placed in a 180 mL flask and heated to 50°C. Acetone (37 g) was then added dropwise, and the mixture was stirred at 50°C for 8 hours, after which it was cooled. The resulting reaction solution was then transferred to a 180 mL pressure vessel, and Pt / C (1.0 g) was added. After replacing the atmosphere in the reactor with nitrogen and hydrogen, the mixture was stirred at 80°C under a hydrogen pressure of 0.8 MPa for 18 hours. After cooling the reaction solution, Pt / C was removed by filtration. The resulting filtrate was concentrated to obtain 56 g of an IP-TETA mixture. GC analysis of the IP-TETA mixture revealed that it contained 31% linear IP-TETA.

[0067] Example 4 [Separation of linear IP-TETA] The IP-TETA mixture (10 g) obtained in Example 3 and toluene (30 g) were placed in a 50 mL glass reactor. Water (1.0 g) was added dropwise while maintaining the internal temperature at approximately 20°C, and the mixture was stirred for 30 minutes. The precipitated crystals and the filtrate were then separated by filtration, and the filtrate was concentrated to remove the solvent. As a result, 2.5 g of crystals and 8.8 g of concentrated residue were obtained. GC analysis of the crystals and concentrated residue revealed that linear IP-TETA was contained in 93% and 20% by GC area ratio, respectively.

[0068] Example 5 [Synthesis of CyHex-TEPA mixture] TEPA (50 g) was placed in a 180 mL flask and heated to 50°C. Cyclohexanone (49 g) was then added dropwise, and the mixture was stirred at 50°C for 5 hours, after which it was cooled. The resulting reaction solution was then transferred to a 180 mL pressure vessel, and Pt / C (1.3 g) was added. After replacing the atmosphere in the reactor with nitrogen and hydrogen, the mixture was stirred at 80°C under a hydrogen pressure of 0.8 MPa for 18 hours. After cooling the reaction solution, the Pt / C was removed by filtration. The filtrate was concentrated to obtain 54 g of a CyHex-TEPA mixture. GC analysis of the CyHex-TEPA mixture showed that it contained 40% linear CyHex-TEPA.

[0069] Example 6 [Separation of linear CyHex-TEPA] The CyHex-TEPA mixture (10 g) obtained in Example 5 and toluene (30 g) were placed in a 50 mL glass reactor. Water (1.0 g) was added dropwise while maintaining the internal temperature at approximately 20°C, and the mixture was stirred for 30 minutes. The precipitated crystals and the filtrate were then separated by filtration, and the filtrate was concentrated to remove the solvent. As a result, 1.8 g of crystals and 8.4 g of concentrated residue were obtained. GC analysis of the crystals and concentrated residue revealed that linear CyHex-TEPA was contained in 82% and 32% by GC area ratio, respectively.

[0070] Example 7 Synthesis of IP-PEHA mixture After PEHA (50 g) was placed in a 180 mL flask, acetone (20 g) was added dropwise and the mixture was stirred at room temperature for 4 hours. The resulting reaction solution was then transferred to a 180 mL pressure vessel, and Pt / C (1.4 g) was added. The atmosphere in the reactor was replaced with nitrogen and then hydrogen, and the mixture was stirred at 80°C and a hydrogen pressure of 0.8 MPa for 6 hours. After cooling the reaction solution, the Pt / C was removed by filtration. The filtrate was concentrated to obtain 52 g of an IP-PEHA mixture. GC analysis of the IP-PEHA mixture revealed that it contained 17% linear IP-PEHA.

[0071] Example 8 [Separation of linear IP-PEHA] The IP-PEHA mixture (10 g) obtained in Example 7 and toluene (20 g) were placed in a 50 mL glass reactor. Water (1.0 g) was added dropwise while maintaining the internal temperature at approximately 20°C, and the mixture was stirred for 30 minutes. The precipitated crystals and the filtrate were then separated by filtration, and the filtrate was concentrated to remove the solvent. As a result, 4.0 g of crystals and 8.2 g of concentrated residue were obtained. GC analysis of the crystals and concentrated residue revealed that linear IP-PEHA was contained in 53% and 10% by GC area ratio, respectively.

[0072] Example 9 1.6 g of the concentrated IP-TEPA residue obtained in Example 2, which had a linear IP-TEPA content of 16%, and 0.4 g of ion-exchanged water were placed in a 15 mL vial to prepare an aqueous amine solution with an amine concentration of 80%. After leaving the solution at room temperature for 18 hours, no crystal precipitation was observed.

[0073] Examples 10 and 11 The same procedure as in Example 9 was carried out except that the amine concentration of the aqueous amine solution was changed to 60% or 40%, and the presence or absence of crystal precipitation was confirmed. No crystal precipitation was observed at any of the concentrations.

[0074] Comparative Examples 1, 2, and 3 The same procedures as in Examples 9, 10, and 11 were carried out to confirm the presence or absence of crystal precipitation, except that the IP-TEPA concentrated residue obtained in Example 2, which had a linear IP-TEPA content of 16%, was replaced with the IP-TEPA mixture obtained in Example 1, which had a linear IP-TEPA content of 54%. Crystal precipitation was observed at all amine concentrations.

[0075] Example 12 The same procedure as in Example 9 was carried out, except that an aqueous amine solution with an amine concentration of 66% was prepared using the IP-TETA concentrated residue with a linear IP-TETA content of 20% obtained in Example 4. No crystal precipitation was observed.

[0076] Example 13 The same procedure as in Example 9 was carried out, except that an aqueous amine solution with an amine concentration of 60% was prepared using the concentrated CyHex-TEPA residue with a linear CyHex-TEPA content of 32% obtained in Example 6. No crystal precipitation was observed.

[0077] Comparative Example 4 The same procedure as in Example 13 was repeated, except that the IP-TETA concentrate residue obtained in Example 6, which had a linear CyHex-TEPA content of 32%, was replaced with the CyHex-TEPA mixture obtained in Example 5, which had a linear CyHex-TEPA content of 40%. Crystal precipitation was observed.

[0078] Example 14 The same procedure as in Example 9 was carried out, except that an aqueous amine solution with an amine concentration of 80% was prepared using the IP-PEHA concentrated residue with a linear IP-PEHA content of 10% obtained in Example 8. No crystal precipitation was observed.

[0079] Example 15 [Separation of linear IP-TEPA] The IP-TEPA mixture (30 g) obtained in Example 1 and toluene (90 g) were placed in a 300 mL glass reactor. Water (4.8 g) was added dropwise while maintaining the internal temperature at about 20°C, and the mixture was stirred for 30 minutes. The precipitated crystals and the filtrate were then separated by filtration, and the filtrate was concentrated to remove the solvent. As a result, 14.7 g of crystals and 20.3 g of concentrated residue were obtained. GC analysis of the crystals and concentrated residue revealed that linear IP-TEPA was contained in 98% and 30% by GC area ratio, respectively.

[0080] Example 16 The same procedure as in Example 9 was carried out, except that an aqueous amine solution with an amine concentration of 40% was prepared using the IP-TEPA concentrated residue with a linear IP-TEPA content of 30% obtained in Example 15. No crystal precipitation was observed.

[0081] Confirmation of crystal precipitation The N-alkylated polyethyleneamine mixture synthesized in the examples and the concentrated residue obtained by separating and concentrating the linear N-alkylated polyethyleneamine were used to prepare aqueous solutions, and the presence or absence of crystal precipitation was confirmed. The results are shown in Table 1.

[0082] [Table 1] [Industrial Applicability]

[0083] According to the present invention, it is possible to provide an N-alkylated polyethyleneamine mixture that can be used as an aqueous solution for separating carbon dioxide, and that does not produce an N-alkylated polyethyleneamine hydrate that would cause the aqueous solution to solidify.

Claims

1. 1. An N-alkylated polyethylene polyamine mixture comprising a linear N-alkylated polyethylene polyamine and a branched N-alkylated polyethylene polyamine, the number of nitrogen atoms contained in each of the linear N-alkylated polyethylene polyamine and the branched N-alkylated polyethylene polyamine is 4 or more, The content of linear N-alkylated polyethylene polyamine is 35% by mass or less based on 100% by mass of the total amount of the mixture. N-alkylated polyethylene polyamine mixture.

2. the number of nitrogen atoms contained in each of the linear N-alkylated polyethylene polyamine and the branched N-alkylated polyethylene polyamine is 4 or more and 6 or less; 2. The N-alkylated polyethylene polyamine mixture of claim 1.

3. 2. The N-alkylated polyethylenepolyamine mixture according to claim 1, wherein the alkyl groups contained in the linear N-alkylated polyethylenepolyamine and the branched N-alkylated polyethylenepolyamine are alkyl groups having 3 or more carbon atoms.

4. 4. The N-alkylated polyethylenepolyamine mixture of claim 3, wherein the alkyl group is an isopropyl group or a cyclohexyl group.

5. 4. The N-alkylated polyethylene polyamine mixture of claim 3, wherein the alkyl group is an isopropyl group.

6. A method for producing the N-alkylated polyethylene polyamine mixture according to claim 1, comprising the following steps 1 to 4: (Step 1) A step of synthesizing an N-alkylated polyethylene polyamine mixture from a polyethylene polyamine mixture (Step 2) Mixing the N-alkylated polyethylene polyamine mixture with water and crystallizing linear N-alkylated polyethylene polyamine hydrate (Step 3) filtering the linear N-alkylated polyethylene polyamine hydrate and separating the hydrate crystals from the filtrate (Step 4) Concentrating the filtrate to obtain an N-alkylated polyethylene polyamine mixture.

Images