Alkoxylated polyalkyleneimines, their preparation and use

Abstract

The present invention provides a method for using a composition comprising an alkoxylated polyalkyleneimine for capturing a gas having a pKa greater than 5, preferably carbon dioxide, from a gas or mixture of gases, the composition comprising the steps of: (a) The following: (i) a polyalkyleneimine; and (ii) alkylene oxide; providing a reaction mixture comprising: (b) carrying out the reaction of (i) a polyalkyleneimine with (ii) an alkylene oxide at a temperature of at least 50°C; and (c) optionally diluting the product of step (b); and a method for preparing a composition comprising an alkoxylated polyalkyleneimine, the method comprising the steps of: In the reaction mixture, the molar ratio of alkylene oxide to NH of polyalkyleneimine is 0.1 to 0.35; The reaction mixture comprises less than 55% by weight of water, preferably less than 30% by weight of water, based on the weight of the reaction mixture, and the reaction mixture comprises less than 5% by weight, preferably less than 1% by weight of a polar organic solvent, based on the weight of the reaction mixture. The present invention also claims a novel composition comprising an alkoxylated polyalkyleneimine, which can be obtained by a similar process as described above, where the alkylene oxide comprises propylene oxide and / or butylene oxide. A method for producing the novel composition is also claimed. The novel composition has been found to be effective in capturing carbon dioxide from gas mixtures, such as air.

Description

[Technical Field]

[0001] The present invention is in the field of alkoxylated polyalkyleneimines, which are used to capture gases having a pKa greater than 5, particularly carbon dioxide, from gases or gases containing the same. The present invention also provides novel compositions of alkoxylated polyalkyleneimines and novel methods for preparing the compositions. The novel compositions have been found to be particularly effective in absorbing carbon dioxide. This method also has the advantage of avoiding the use of volatile organic compounds, particularly polar organic solvents. [Background technology]

[0002] Rising atmospheric concentrations of greenhouse gases have attracted growing global attention due to their predicted impact on climate change. This trend is particularly pronounced for rising carbon dioxide concentrations. It is widely recognized that even current atmospheric carbon dioxide concentrations are causing dramatic environmental changes, including droughts, floods, and ecosystem disruption around the world. If carbon dioxide concentrations continue to rise, it is predicted that average atmospheric and ocean temperatures will rise significantly, leading to melting of polar and glacial ice, rising sea levels, and unavoidable flooding of low-lying areas. Rising atmospheric temperatures are also expected to increase the likelihood of powerful cyclonic storms worldwide.

[0003] Many governments are enacting legislation to reduce greenhouse gas emissions, particularly carbon dioxide, and ultimately limit global warming. Many countries have adopted the Paris Agreement, a legally binding international treaty on climate change, whose goal is to limit global warming to well below 2°C, and preferably 1.5°C, above pre-industrial levels.

[0004] In recent years, significant efforts have been made to develop technologies to achieve the goal of reducing carbon dioxide from the atmosphere and / or gaseous emissions. Capturing carbon dioxide at its source is generally considered the most cost-effective method, typically from large carbon-based energy facilities, natural gas processing, synthetic fuel plants, carbon dioxide-intensive industries such as steel and cement manufacturing, and fossil-fuel-based hydrogen production plants.

[0005] A major focus of carbon capture technology is the absorption or sequestration of carbon dioxide. The active compounds used for carbon dioxide absorption overwhelmingly rely on amine chemistry. Typical amines used for this purpose include alkanolamines such as monoethanolamine, diethanolamine, diisopropanolamine, pentaethylenehexamine, tetraethylenepentamine, triethylenetetramine, tetraethylenetetramine, bis(2-hydroxypropyl)amine, N,N'-bis(2-hydroxyethyl)ethylenediamine, alkylamines, methylamines, linear polyethyleneimine, branched polyethyleneimine, dimethylamine, diethylamine, methyldiethanolamine, methylethanolamine, polyethylenepolyamines, diethylenetriamine, and N,N'-bis-(3-aminopropyl)ethylenediamine.

[0006] U.S. Patent No. 9,084,960 B2 discloses a method for reducing the CO2 content in gas, employing CO2 capture agents including monoamines (especially secondary amines such as diethanolamine), polyamines, monoguanidines, polyguanidines, and mixtures of these compounds.

[0007] U.S. Patent No. 9,533,250 B2 relates to CO2 reduction from indoor air from enclosed spaces. This document describes amine-based compounds and suggests that the amine-based compounds include any suitable amine, such as a primary or secondary amine, or a combination thereof. According to this disclosure, amine-based compounds range from simple single molecules such as ethanolamine to high molecular weight amine polymers such as polyethyleneimine. This document suggests any one or combination of several polyamines, such as monoethanolamine, ethanolamine, methylamine, branched polyethyleneimine, linear polyethyleneimine, diethanolamine, dimethylamine, diethylamine, diisopropanolamine, tetraethylenepentamine, methyldiethanolamine, methylethanolamine, and polyethyleneimine.

[0008] U.S. Patent No. 11,229,897 B2 discloses a gas-absorbing material containing a polyamine produced using a process that does not contain formaldehyde as a reaction product and / or reactant. This disclosure describes preparing a reaction solution of a primary amine compound with a reactant. The reactant is said to include a carbonate compound or a ketone compound. The primary amine compound reacts with the reactant to produce a secondary amine compound.

[0009] U.S. Patent No. 10,010,861 B2 describes polymeric amines related to carbon dioxide absorption. The polymeric amines are said to consist of a polymer backbone containing nitrogen atoms and branched chains attached to the nitrogen atoms of the polymer backbone. Each branched chain contains at least one nitrogen atom, and the polymeric amine is modified by substituting at least one nitrogen atom of the polymer backbone or branched chain with a hydroxyl-containing carbon chain. Example 1 describes the synthesis of polyethyleneimine modified by partial substitution with butylene oxide. In this synthesis, polyethyleneimine (Mn=1200, 19 mmol N / g) is dissolved in methanol. The disclosure describes adding butylene oxide to a polyethyleneimine / methanol solution in different amounts so that the molar ratios of butylene oxide to nitrogen atoms present in the polyethyleneimine are 0.15:1, 0.37:1, and 0.54:1. The disclosure also describes removing the solvent by heating the modified polyethyleneimine solution in a vacuum oven.

[0010] U.S. Patent No. 10,751,689 B2 discloses modified polyamines related to carbon dioxide absorption. The modified polyamines are reaction products of amines and epoxides. Example 1 describes the preparation of modified polyamine species based on pentaethylenehexamine (PEHA) and propylene oxide (PO). The preparation involves dissolving 10 g of PEHA in 40 mL of water, adding 5 g of PO to the PEHA solution, and then stirring at room temperature for 20 hours. The temperature of the reaction mixture is gradually increased to 60°C and maintained for 2 hours. Water is removed using a rotary evaporator, followed by a vacuum of less than 1 mmHg overnight.

[0011] The alkoxylation of polyalkyleneimines is well known and has been described in the literature, for example, the alkoxylation of polyethyleneimines with ethylene oxide, propylene oxide, and butylene oxide is described in Houben-Weyl, Methoden der organischen Chemie, 4th Ed., Vol. 14 / 2, p. 440ff. (1963) and Vol. E20, p. 1367f. (1987).

[0012] U.S. Patent Publication No. 2021309934 A1 relates to a method for producing ethoxylated polyethyleneimine by reacting at least one polyethyleneimine (PEI) with at least one ethylene oxide EO. In a first step (1), polyethyleneimine (PEI) is reacted with ethylene oxide EO in an amount of less than 1 molar equivalent per PEI, and then in a second step (2), the product of step (1) is reacted with an additional amount of ethylene oxide EO in the presence of a basic catalyst. The ethylene oxide EO is added in step (1) in an amount of 0.01 to 0.85 ethylene oxide units per NH group of polyethyleneimine (PEI). The polyethyleneimine (PEI) has a molecular weight M in the range of 1,000 to 5,000. W (before ethoxylation). This document appears to address the problem that when ethoxylated polyethyleneimine prepared by known processes is incorporated into laundry formulations, the viscosity of the resulting liquid decreases, reducing consumer acceptance of the formulation and requiring additional thickening technology. It shows that by using a two-stage process for the initial ethoxylation of PEI and adjusting the amount of EO added in the first stage (and second stage) to a specific range (strong under-hydroxyethylation), the problems of the prior art can be significantly alleviated. [Prior art documents] [Patent documents]

[0013] [Patent Document 1] U.S. Patent No. 9,084,960 B2 [Patent Document 2] U.S. Patent No. 9,533,250 B2 [Patent Document 3] US Patent No. 11,229,897 B2 [Patent Document 4] U.S. Patent No. 10,010,861 B2 [Patent Document 5] US Patent No. 10,751,689 B2 [Patent Document 6] U.S. Patent Publication No. 2021309934 A1 [Non-patent literature]

[0014] [Non-Patent Document 1] Houben-Weyl, Methoden der organischen Chemie, 4.Ed., Vol.14 / 2, p.440ff.(1963) and Vol.E20, p.1367f.(1987) Summary of the Invention [Problem to be solved by the invention]

[0015] The inventors of the present invention set out with the object of providing an alkoxylated polyethyleneimine which has improved activity for capturing carbon dioxide compared to the state-of-the-art conventional alkoxylated polyethyleneimines used for this purpose. A further object of the present invention is to provide a simple method for providing an alkoxylated polyethyleneimine which is suitable for capturing carbon dioxide and preferably has improved activity for this purpose. [Means for solving the problem]

[0016] According to a first aspect of the present invention there is provided a method of use of a composition comprising an alkoxylated polyalkyleneimine, preferably an alkoxylated polyethyleneimine, for capturing a gas having a pKa greater than 5, preferably carbon dioxide, from a gas or mixture of gases, the composition comprising the following steps: (a) The following: (i) a polyalkyleneimine, preferably polyethyleneimine; and (ii) alkylene oxide; providing a reaction mixture comprising: (b) carrying out the reaction of (i) a polyalkyleneimine, preferably polyethyleneimine, with (ii) an alkylene oxide at a temperature of at least 50°C; and (c) optionally diluting the product of step (b); and the molar ratio of alkylene oxide to NH- units of polyalkyleneimine, polyethyleneimine in the reaction mixture is 0.1 to 0.35; The reaction mixture comprises less than 55% by weight of water, preferably less than 30% by weight of water, based on the weight of the reaction mixture, and the reaction mixture comprises less than 5% by weight, preferably less than 1% by weight of a polar organic solvent, based on the weight of the reaction mixture.

[0017] NH represents the number of amines and is calculated by determining the number of secondary and primary amino groups, as follows: NH = (number of secondary amino groups) + (2 × (number of primary amino groups)). NH is determined by titrating each polyalkyleneimine with trifluoromethanesulfonic acid.

[0018] A second aspect of the present invention is a method for producing a pharmaceutical composition comprising the steps of: (a) The following: (i) a polyalkyleneimine, preferably polyethyleneimine; and (ii) alkylene oxides, including propylene oxide and / or butylene oxide; providing a reaction mixture comprising: (b) carrying out the reaction of (i) a polyalkyleneimine, preferably polyethyleneimine, with (ii) an alkylene oxide at a temperature of at least 50°C; and (c) optionally diluting the product of step (b); The present invention relates to a method for preparing a composition comprising an alkoxylated polyalkyleneimine, preferably an alkoxylated polyethyleneimine, which can be obtained by a method comprising: wherein the molar ratio of alkylene oxide to NH- units of polyalkyleneimine, polyethyleneimine in the reaction mixture is 0.1 to 0.35; The reaction mixture comprises less than 55% by weight of water, preferably less than 30% by weight of water, based on the weight of the reaction mixture, and the reaction mixture comprises less than 5% by weight, preferably less than 1% by weight of a polar organic solvent, based on the weight of the reaction mixture.

[0019] A third aspect of the present invention provides a composition comprising an alkoxylated polyalkyleneimine, preferably an alkoxylated polyethyleneimine, wherein the alkoxylated polyalkyleneimine, preferably an alkoxylated polyethyleneimine composition, is prepared by the following steps: (a) The following: (i) a polyalkyleneimine, preferably polyethyleneimine; and (ii) alkylene oxides, including propylene oxide and / or butylene oxide; providing a reaction mixture comprising: (b) carrying out the reaction of (i) a polyalkyleneimine, preferably polyethyleneimine, with (ii) an alkylene oxide at a temperature of at least 50°C; and (c) optionally diluting the product of step (b); can be obtained by a method comprising wherein the molar ratio of alkylene oxide to NH- units of polyalkyleneimine, polyethyleneimine in the reaction mixture is 0.1 to 0.35; The reaction mixture comprises less than 55% by weight of water, preferably less than 30% by weight of water, based on the weight of the reaction mixture, and the reaction mixture comprises less than 5% by weight, preferably less than 1% by weight of a polar organic solvent, based on the weight of the reaction mixture. DETAILED DESCRIPTION OF THE INVENTION

[0020] The present inventors have unexpectedly found that the alkoxylated polyalkyleneimines, and in particular alkoxylated polyethyleneimines, provided by the newly developed method exhibit particularly improved results in terms of carbon dioxide capture compared to state-of-the-art alkoxylated polyalkyleneimines.

[0021] Without being limited by theory, the inventors of the present invention believe that by using no or substantially no polar organic solvents (i.e., less than 5%, preferably less than 1%) and by using no or limited amounts of water (i.e., less than 55% water, preferably less than 30% water, based on the weight of the reaction mixture), competing side reactions are avoided compared to processes for the alkoxylation of polyalkyleneimines that use higher levels of solvent. Indeed, the low ratio of alkylene oxide to NH prevents such competing reactions that may interfere with the alkoxylation, so that the alkoxylation at the desired ratio is at least substantially complete.

[0022] This method is believed to be much more suitable for commercial-scale production of alkoxylated polyethyleneimines with low alkylene oxide to NH ratios. The present inventors have realized that a narrow weight ratio of alkylene oxide to NH of the polyalkyleneimine of 0.1 to 0.35, combined with the absence or substantial absence of organic solvents and the absence or limited presence of water, provides alkoxylated polyalkyleneimines that are more effective for carbon dioxide absorption purposes. This is something that could not be inferred or predicted by those skilled in the art.

[0023] The reaction mixture in the process suitably contains less than 3% by weight, often less than 2% by weight, preferably less than 1% by weight, e.g., less than 7500 ppm, more preferably less than 5000 ppm, particularly preferably less than 1000 ppm, less than 500 ppm, more particularly preferably less than 100 ppm, and particularly preferably less than 50 ppm, of polar organic solvent, based on the weight of the reaction mixture. Most preferably, the reaction mixture does not contain any polar organic solvent. The inventors believe that completely avoiding polar organic solvents most effectively avoids the risk of undesired competing side reactions and provides a more effective product. Furthermore, the inventors unexpectedly found that the reaction rate is greater when carried out in the absence of polar organic solvents. Such an increase in reaction rate is beneficial in terms of production time and cost, and would be particularly useful when considering a continuous process. Furthermore, the inventors have found that by omitting polar organic solvents from the reaction mixture, less alkylene oxide remains in the reaction product. Reducing the level of alkylene oxide in the alkoxylated polyalkyleneimine is important to product safety in view of the high toxicity of alkylene oxide.

[0024] The term "polar organic solvent" refers to an organic compound exhibiting polarity that is generally used as a solvent. Typically, such organic solvents are organic liquids that dissolve or are miscible with polyalkyleneimines or alkoxylated polyalkyleneimines. Specific examples of such polar organic solvents include methanol, ethanol, isopropanol, acetone, DMF, and chloroform.

[0025] Thus, compositions comprising an alkoxylated polyalkyleneimine, preferably an alkoxylated polyethyleneimine, produced according to the present invention preferably contain less than 150 ppm, preferably less than 100 ppm, more preferably less than 50 ppm, more preferably less than 20 ppm, particularly preferably less than 10 ppm, and more particularly preferably less than 5 ppm of residual alkylene oxide, based on the weight of alkoxylated polyalkyleneimine in the composition.

[0026] These alkylene oxide concentrations can be determined by thermal desorption, in which the released volatiles are quantified by gas chromatography-mass spectrometry. The GC / MS used to calculate the values ​​in this disclosure was provided by Agilent. The system configuration was a GC-MS Kopplung (7890 / 5975 or 7890 / 5977) equipped with an electron ionization source and a single quadruple spectrometer.

[0027] The alkoxylated polyalkyleneimine, preferably alkoxylated polyethyleneimine, according to the present invention can be obtained by a process in which the amount of water in the reaction mixture must be less than 55% by weight based on the weight of the reaction mixture. Desirably, the amount of water in the reaction mixture should be less than 50% by weight, usually less than 40% by weight, typically 36% or less or 35% or less by weight, but usually less than 35% by weight, based on the weight of the reaction mixture. Preferably, the amount of water in the reaction mixture should be less than 30% by weight of the reaction mixture. Desirably, the amount of water should be less than 20% by weight of the reaction mixture. The amount of water in the reaction mixture is, for example, 17% or less by weight of the reaction mixture, typically 16% or less by weight of the reaction mixture, for example 15% or less by weight of the reaction mixture, but often less than 15% by weight, preferably 13% or less by weight, or 12% or less by weight, often less than 12% by weight, more preferably 11% or less by weight, or 10% or less by weight, usually less than 10% by weight, for example less than 5% by weight. Even more preferably, the amount of water present in the reaction mixture should be less than 2% by weight, especially less than 1% by weight, based on the weight of the reaction mixture. Particularly preferably, the reaction mixture is free of water.

[0028] In one desirable embodiment, the reaction mixture is solvent-free and contains water as the only reactant, suitably in an amount of 1 mole or less per mole of NH group of the polyalkyleneimine, preferably polyethyleneimine, which means that the amount of water present in the reaction mixture as a reactant is 1 mole of water per mole of NH group of the polyalkyleneimine, preferably polyethyleneimine, to be alkoxylated.

[0029] The process for producing alkoxylated polyalkyleneimines, preferably alkoxylated polyethyleneimines, can be continuous, batch, semi-batch, or fed-batch. Preferably, the process is fed-batch and / or continuous. Desirably, a fed-batch process involves one or more reactants (first reactant(s)) being placed in a reaction vessel while an additional reactant or reactants (second reactant(s)) are fed to the reaction vessel at a defined rate and mixed with the first reactant(s) as the reaction proceeds to form a reaction mixture.

[0030] In a desired embodiment, steps (a) and (b) of the method can be performed partially, largely, or wholly simultaneously.

[0031] In one embodiment, in step (a) of the process, (i) a polyalkyleneimine, preferably polyethyleneimine, is suitably provided in a reaction vessel. Preferably, the polyalkyleneimine, preferably polyethyleneimine, is provided at a temperature of at least 50°C. Suitably, the polyalkyleneimine, preferably polyethyleneimine, may be provided at a temperature of from 50°C to 150°C, preferably from 60°C to 140°C, more preferably from 60°C to 110°C. Desirably, (ii) an alkylene oxide is provided at a temperature of at least 50°C, suitably from 50°C to 110°C, preferably from 60°C to 100°C, and is combined with (i) the polyalkyleneimine, preferably polyethyleneimine, to form a reaction mixture.

[0032] Preferably, (ii) alkylene oxide is combined with (i) polyalkyleneimine, preferably polyethyleneimine, by feeding it to (i) polyalkyleneimine, preferably polyethyleneimine, at a defined rate to form a reaction mixture. Reaction (b) begins when (ii) alkylene oxide is fed to (i) polyalkyleneimine, preferably polyethyleneimine. Thus, the reaction in this embodiment begins and proceeds as alkylene oxide is fed to the reaction mixture.

[0033] The reaction in step (b) is desirably initiated by raising the temperature of the reaction mixture. Suitably, the reaction in step (b) can be carried out at a temperature of at least 60°C, more suitably 60°C to 140°C, preferably 75°C to 135°C, more preferably 80°C to 130°C, and even more preferably 80°C to 130°C.

[0034] Preferably, the reaction in step (b) may be carried out in a pressurized reaction vessel, for example at a pressure above 1 bar. Preferably, the reaction is carried out at a pressure above 1.25 bar, preferably at a pressure of from 1.5 to 3 bar.

[0035] It may be desirable to provide a composition comprising an alkoxylated polyalkyleneimine, preferably an alkoxylated polyethyleneimine, in diluted form. Accordingly, in this regard, following reaction step (b), the composition comprising the reaction product thus formed can be diluted with water in dilution step (c). In a preferred embodiment in which reaction step (b) is carried out at elevated pressure as set forth above, dilution step (c) should be carried out after the reaction mixture in the reaction vessel has been depressurized. Desirably, the product of reaction step (b) can be diluted with water to provide an aqueous solution of 50% to 70% by weight of alkoxylated polyalkyleneimine, preferably alkoxylated polyethyleneimine, based on the weight of the aqueous solution.

[0036] In this method, the molar ratio of alkylene oxide to NH of the polyalkyleneimine, preferably polyethyleneimine, is 0.1 to 0.35. Preferably, the molar ratio of alkylene oxide to NH is 0.15 to 0.32. As described above, NH represents the amine number and is calculated by determining the number of secondary amino groups and primary amino groups, where NH = (number of secondary amino groups) + (2 × (number of primary amino groups)). NH is determined by titrating each polyalkyleneimine with trifluoromethanesulfonic acid.

[0037] The (i) alkylene oxide may be any alkylene oxide suitable for the alkoxylation of polyalkyleneimine, preferably polyethyleneimine. References to alkylene oxides, such as propylene oxide or butylene oxide, used throughout this specification refer to 1,2-epoxy-substituted compounds unless otherwise specified. (i) alkylene oxides containing at least three carbon atoms have been found to be particularly suitable for capturing gases with a pKa greater than 5, preferably carbon dioxide. In one preferred embodiment, the alkylene oxide is one or more C3-C 12 -Alkylene oxide, preferably C3-C 10 The alkylene oxide may be a mixture of C3-C4-alkylene oxide, more desirably C3-C8-alkylene oxide, preferably propylene oxide and / or butylene oxide. Preferably, the alkylene oxide comprises propylene oxide and / or butylene oxide. Thus, the alkylene oxide may be propylene oxide, butylene oxide, or a mixture of propylene oxide and butylene oxide, and the alkylene oxide comprising propylene oxide and / or butylene oxide may comprise a mixture of either or both of propylene oxide and butylene oxide with a higher alkylene oxide. In a preferred embodiment, the alkylene oxide is a C3-C4-alkylene oxide, i.e., propylene oxide or butylene oxide, and a C8-C 12 -alkylene oxides, including mixtures of C3-C4-alkylene oxides and C8-C 12 the molar ratio of alkylene oxide is 2:1 to 20:1, 3:1 to 15:1, 4:1 to 12:1, more preferably 5:1 to 10:1 or 5:1 to 9:1. Particularly preferred mixtures of alkylene oxides include mixtures of propylene oxide and any of 1-octene oxide, 1-decene oxide or 1-dodecene oxide, preferably in ratios within the aforementioned ranges; or mixtures of butylene oxide and any of 1-octene oxide, 1-decene oxide or 1-dodecene oxide, preferably in ratios within the aforementioned ranges.

[0038] The alkoxylated polyalkyleneimines contained in the compositions of the present invention or prepared according to the methods of the present invention may be linear or branched. In particular, in the case of branched polyalkyleneimines, the branching may occur at the nitrogen fraction thereof. Linear polyalkyleneimines are composed exclusively of repeating units of formula A; branched polyalkyleneimines, in addition to the linear repeating units, have a tertiary nitrogen atom according to formula B: [ka] (wherein Q is C2 to C8 alkylene, suitably ethylene, propylene or butylene, and preferably ethylene).

[0039] Polyalkyleneimines, especially polyethyleneimines, having a degree of branching (DB) of more than 50, preferably more than 60, are preferred. Polyalkyleneimines, including polyethyleneimines, can be characterized by their degree of branching (DB). For the definition of the degree of branching, reference is made to H. Frey et al., Acata Polym. 1997, 48, 30. The degree of branching DB is defined as follows: DB(%) = (T + Z) / (T + Z + L) × 100 (wherein T is the average number of terminally bonded monomer units (primary amino groups), Z is the average number of branched monomer units (tertiary amino groups), L is the average number of monomer units (secondary amino groups) bonded to a linear chain. T, Z, and L are the values ​​in DO. 13 It can be determined by C-NMR. References include T. St. Pierre & M. Geckle (1985) 13 C-NMR Analysis of Branched Polyethyleneimine, Journal of Macromolecular Science: Part A-Chemistry, 22:5-7,877-887, DOI:10.1080 / 00222338508056641.

[0040] The branching degree DB of the polyalkyleneimine, particularly polyethyleneimine, according to the present invention is preferably in the range of 55 to 95%, preferably in the range of 57 to 90%, more preferably in the range of 60 to 80%.

[0041] The polyalkyleneimine, preferably polyethyleneimine, employed in the reaction mixture preferably has a mass average molecular weight (M) of 300 to 20,000, for example 300 to 15,000, suitably 300 to 10,000, more suitably 300 to 5,000, preferably 500 to 1,500, more preferably 500 to 1,000 g / mol. W ) can be included.

[0042] Polyalkyleneimines suitable for forming the alkoxylated polyalkyleneimines can be prepared by a variety of methods understood in the art, for example, polyethyleneimines can be prepared by the ring-opening of aziridines by acid-catalyzed polymerization. In various desirable embodiments, the polyethyleneimine is preferably a branched polymer containing groups such as those represented by Formula C and Formula D: [ka] (wherein n or m represents a mass average molecular weight (M W ), typically from about 7 to about 500. It is also contemplated that the polyethyleneimine may have any value or range of values, both integer and fractional, within the above ranges.

[0043] Preferably, the alkoxylated polyethyleneimine is derived from branched polyethyleneimine, which is a branched polymer having the following exemplary structure:

[0044] [ka]

[0045] With further reference to the exemplary structure above, the branched structure of polyethyleneimine provides primary, secondary, and tertiary amines. That is, polyethyleneimine typically includes a linear group (L), a dendritic group (D), and a terminal group (T). In the exemplary structure above, * represents the remainder of the polyethyleneimine molecule.

[0046] In some embodiments, the branched polyethyleneimine is 13 Based on 100 percent of all groups present in the branched polyethyleneimine, as determined via C-NMR, the branched polyethyleneimine comprises about 20 to about 55, or about 30 to about 45 percent linear groups (L); about 10 to about 40, or about 20 to about 30 percent dendritic groups (D); and about 20 to about 55, or about 30 to about 45 percent terminal groups (T). In additional non-limiting embodiments, all values ​​and ranges of values, both whole and fractional, within one or more of the foregoing ranges are expressly contemplated herein.

[0047] Suitable alkoxylated polyethyleneimines can be derived from polyethyleneimines commercially available from BASF under the trade name LUPASOL®.

[0048] In one particularly preferred embodiment of the present invention, the alkoxylated polyalkyleneimine, preferably the alkoxylated polyethyleneimine, has a weight average molecular weight (M W ), wherein the alkoxylation is provided by either ethylene oxide, propylene oxide or butylene oxide, particularly preferably propylene oxide or butylene oxide, most preferably propylene oxide.

[0049] The alkoxylated polyalkyleneimine, preferably the alkoxylated polyethyleneimine, desirably has an OH / NH molar ratio of 0.20 to 0.35. The OH / NH ratio is 13It can be determined using C NMR.

[0050] Compositions comprising an alkoxylated alkyleneimine, preferably an alkoxylated polyethyleneimine, according to the third aspect of the present invention particularly preferably contain less than 10 ppm, more particularly preferably less than 5 ppm, of alkylene oxide relative to the mass of alkoxylated polyalkyleneimine in the composition. These concentrations can be determined by thermal desorption, with the released volatiles quantified by gas chromatography-mass spectrometry. The GC / MS used to calculate the values ​​according to the present disclosure was provided by Agilent. The system configuration was a GC-MS Kopplung (7890 / 5975 or 7890 / 5977) equipped with an electron ionization source and a single quadruple spectrometer.

[0051] The inventors have found that a composition comprising an alkoxylated polyalkyleneimine, preferably an alkoxylated polyethyleneimine, can be obtained by the above-described method, including any of its preferred embodiments, for capturing a gas having a pKa greater than 5. Preferably, the gas is carbon dioxide. According to the use of the present invention, a gas having a pKa greater than 5, preferably carbon dioxide, is captured from a gas or mixture of gases. In one preferred embodiment of the method of use of the present invention, the alkoxylated polyalkyleneimine, preferably the alkoxylated polyethyleneimine, can be used directly, used as an aqueous solution, or incorporated into a liquid formulation.

[0052] Furthermore, once the alkoxylated polyalkyleneimine in the composition is completely filled with a gas, such as carbon dioxide, having a pKa greater than 5, the composition can be subjected to a desorption process.The desorption process can be suitably carried out by heating, so that the gas, such as carbon dioxide, is released, and then in a process that is more permanently stored in a controlled environment.The desorption of gases such as carbon dioxide is well known in the art.This absorption / desorption of gases such as carbon dioxide is called absorption / desorption cycle.

[0053] The present inventors have found that compositions containing alkoxylated polyalkyleneimines can absorb carbon dioxide more quickly. This is true whether the composition is a liquid composition, such as an aqueous solution containing the alkoxylated polyalkyleneimine, or contained as part of a solid molded article or product. Thus, compositions containing alkoxylated polyalkyleneimines can reach full capacity, i.e., become fully charged with CO2, in a shorter time span, typically up to 80% or more, than conventional alkoxylated polyalkyleneimines prepared by conventional routes. This means that the overall duration of the absorption / desorption cycle can be shortened and the number of absorption / desorption cycles can be increased by at least 200%. This has the advantage of reducing capital investment and process costs.

[0054] The increase in turnover rate (i.e., absorption / desorption cycles) is importantly due to an increase in the uptake / absorption rate and the desorption rate. More preferably, the gas or mixture of gases is either atmospheric air or any type of exhaust gas. Typically, exhaust gases are emitted from industrial processes, including, for example, power plants, and are typically gases produced from the combustion of carbonaceous materials. Furthermore, exhaust gases can originate from a variety of other devices, such as heat-generating devices, including commercial and domestic boilers, or motion-generating devices, such as, for example, vehicle combustion engines. The capture of carbon dioxide from air typically refers to any air in the atmosphere, but can also include air in enclosed spaces, such as, for example, buildings.

[0055] The following examples are intended to illustrate the present invention and are not intended to limit the scope of the invention in any way. [Example]

[0056] Comparative Examples 1 to 3 Comparative Example 1 A 2 L glass flask equipped with a stirrer and reflux funnel was charged with 465 g of polyethyleneimine (PEI, Mw 800 g / mol, amine value 18.2 mmol / g). The mixture was heated to 30 °C while purging with nitrogen for 20 minutes. 500 g of methanol was added (300 rpm). While maintaining the temperature at 30-35 °C, 147.3 g of propylene oxide (PO) was added over 3 hours. The mixture was gently refluxed at 40 °C overnight with stirring. The methanol was then removed within 45 minutes. Finally, the temperature was increased to 80 °C over an additional 45 minutes, and a 40 mbar vacuum was applied for 15 minutes. The resulting yellowish mixture was quenched with nitrogen and cooled to room temperature (approximately 20 °C), yielding 615 g of a yellowish viscous liquid.

[0057] Comparative Example 2 A 2 L glass flask equipped with a stirrer and reflux funnel was charged with 470 g of polyethyleneimine (PEI, Mw 1200 g / mol, amine value 17.9 mmol / g). While heating the mixture to 30 °C, 115 g of water and 500 g of methanol were added (300 rpm) and purged with nitrogen for 20 minutes. While maintaining the temperature at 30-35 °C, 151.5 g of butylene oxide (BuO) was added over 3 hours. The mixture was stirred and gently refluxed at 40 °C overnight. The temperature was then increased to 100 °C while removing methanol and water (90 minutes). After a 45-minute hold at 100 °C, a 40 mbar vacuum was applied for 30 minutes. The resulting yellowish mixture was quenched with nitrogen and cooled to room temperature (approximately 20 °C), yielding 623.9 g of a yellowish viscous liquid.

[0058] Comparative Example 3 A 2 L glass flask equipped with a stirrer and reflux funnel was charged with 500 g of polyethyleneimine (PEI, Mw 5000 g / mol, amine value 17.7 mmol / g). The mixture was heated to 50 °C while adding 935 g of water (300 rpm) and purging with nitrogen for 20 minutes. While maintaining the temperature at 50-65 °C, 135 g of butylene oxide (BuO) was added over 3 hours. The mixture was stirred at 60 °C overnight. The temperature was then increased to 100-105 °C while partially removing water (30 minutes). After a 45 minute hold at 100 °C, a 40 mbar vacuum was applied for 10 minutes. The resulting yellowish mixture was quenched with nitrogen and cooled to room temperature (approximately 20 °C). 1250 g of a yellowish viscous liquid was obtained, which was diluted with 20 g of water to a 50% aqueous solution.

[0059] Examples 1 to 13 of the present invention Example 1 A 5 L stainless steel reactor equipped with a stirrer was charged with 2700 g of polyethyleneimine (PEI) (MW 800 g / mol, amine number 18.2 mmol / g). The reactor was evacuated (60 mbar) and purged with nitrogen three times while the temperature was increased to 110°C. The reactor was pressurized to 2 bar, and propylene oxide (PO) addition was initiated with 125 g of PO within 5 minutes. An additional 720 g of PO was added over 3.5 hours while stirring at 150 rpm. The temperature was increased to 120°C and stirring continued for another 3 hours. The reactor was then cooled to 60°C and depressurized. Finally, the reactor was pressurized at 100 mbar for 20 minutes and purged with nitrogen. 3551 g of a slightly yellowish viscous liquid was obtained.

[0060] Example 2 A 5 L stainless steel reactor equipped with a stirrer was charged with 2700 g of PEI (MW 800 g / mol, amine number 18.2 mmol / g). The reactor was evacuated (60 mbar) and purged with nitrogen three times while the temperature was increased to 100°C. The reactor was pressurized to 2 bar, and propylene oxide addition was started with 112 g of PO within 5 minutes. An additional 700 g of PO was added over 3 hours while stirring at 150 rpm. The temperature was increased to 115°C and stirring was continued for another 3 hours. The reactor was then cooled to 60°C and depressurized. Finally, the reactor was pressurized at 100 mbar for 20 minutes and purged with nitrogen. 3409 g of a slightly yellowish viscous liquid was obtained.

[0061] Example 3 A 5 L stainless steel reactor equipped with a stirrer was charged with 2700 g of PEI (MW 800 g / mol, amine number 18.2 mmol / g). The reactor was evacuated (60 mbar) and purged with nitrogen three times while the temperature was increased to 100 °C. The reactor was pressurized to 2 bar, and butylene oxide (BuO) addition was started with 125 g of BuO within 5 min. An additional 760 g of BuO was added over 3 h while stirring at 150 rpm. The temperature was increased to 115 °C, and stirring was continued for another 4 h. The reactor was then cooled to 60 °C and depressurized. Finally, the reactor was pressurized at 100 mbar for 20 min and purged with nitrogen. 3581 g of a clear, viscous liquid was obtained.

[0062] Example 4 A 5 L stainless steel reactor equipped with a stirrer was charged with 2700 g of PEI (Mw 1200 g / mol, amine number 17.9 mmol / g). The reactor was evacuated (60 mbar) and purged with nitrogen three times while the temperature was increased to 100°C. The reactor was pressurized to 2 bar, and propylene oxide (PO) addition was started with 117 g of PO within 5 minutes. An additional 640 g of PO was added over 3 hours while stirring at 150 rpm. The temperature was increased to 115°C and stirring was continued for another 3 hours. The reactor was then cooled to 60°C and depressurized. Finally, the reactor was pressurized at 100 mbar for 20 minutes and purged with nitrogen. 3452 g of a slightly yellowish viscous liquid was obtained.

[0063] Example 5 A 5 L stainless steel reactor equipped with a stirrer was charged with 2700 g of PEI (Mw 1200 g / mol, amine number 17.9 mmol / g). The reactor was evacuated (60 mbar) and purged with nitrogen three times while the temperature was increased to 110°C. The reactor was pressurized to 2 bar, and propylene oxide (PO) addition was started with 105 g of PO within 5 minutes. An additional 400 g of PO was added over 2.5 hours while stirring at 150 rpm. The temperature was increased to 115°C and stirring was continued for another 3 hours. The reactor was then cooled to 60°C and depressurized. Finally, the reactor was pressurized at 100 mbar for 20 minutes and purged with nitrogen. 3202 g of a slightly yellowish viscous liquid was obtained.

[0064] Example 6 A 5 L stainless steel reactor equipped with a stirrer was charged with 2700 g of PEI (Mw 1200 g / mol, amine number 17.9 mmol / g). The reactor was evacuated (60 mbar) and purged with nitrogen three times while the temperature was increased to 100°C. The reactor was pressurized to 2 bar, and propylene oxide (PO) addition was started with 117 g of PO within 5 minutes. An additional 640 g of PO was added over 3.5 hours while stirring at 150 rpm. The temperature was increased to 115°C and stirring was continued for another 3 hours. The reactor was then cooled to 60°C and depressurized. Finally, the reactor was pressurized at 100 mbar for 10 minutes and purged with nitrogen. 3913 g of a slightly yellowish liquid was obtained.

[0065] Example 7 A 5 L stainless steel reactor equipped with a stirrer was charged with 2700 g of PEI (Mw 5000 g / mol, amine number 17.7 mmol / g) followed by 385 g of water. The reactor was evacuated (60 mbar) and purged with nitrogen three times while the temperature was increased to 100 °C. The reactor was pressurized to 2 bar, and butylene oxide (BuO) addition was started with 129 g of BuO within 5 minutes. An additional 600 g of BuO was added over 3.5 hours while stirring at 150 rpm. The temperature was increased to 120 °C and stirring continued for another 3 hours. The reactor was then cooled to 60 °C and depressurized. Finally, the reactor was pressurized at 100 mbar for 10 minutes and purged with nitrogen. 3799 g of a clear liquid was obtained.

[0066] Example 8 A 5 L stainless steel reactor equipped with a stirrer was charged with 2700 g of PEI (Mw 5000 g / mol, amine number 17.7 mmol / g). The reactor was evacuated (60 mbar) and purged with nitrogen three times while the temperature was increased to 100 °C. The reactor was pressurized to 2 bar, and propylene oxide (PO) addition was started with 105 g of PO within 5 min. An additional 200 g of PO was added over 1.5 h while stirring at 150 rpm. In the next step, 380 g of butylene oxide (BuO) was charged within 2 h, the temperature was increased to 120 °C, and stirring was continued for another 3 h. The reactor was then cooled to 60 °C and depressurized. Finally, the reactor was pressurized at 100 mbar for 20 min and purged with nitrogen. 3380 g of a clear liquid was obtained.

[0067] Example 9 A 5 L stainless steel reactor equipped with a stirrer was charged with 2700 g of PEI (Mw 1200 g / mol, amine number 17.9 mmol / g). The reactor was evacuated (60 mbar) and purged with nitrogen three times while the temperature was increased to 100 °C. After adding 291 g of 1-decene oxide (DO), the reactor was pressurized to 2 bar. Propylene oxide (PO) was added (648 g) within 3.5 h. The temperature was increased to 115 °C and stirred for an additional 3 h. The reactor was then cooled to 60 °C and depressurized. Finally, the reactor was pressurized at 100 mbar for 20 min and purged with nitrogen. 3636 g of a slightly yellowish viscous liquid was obtained.

[0068] Example 10 A 5 L stainless steel reactor equipped with a stirrer was charged with 2700 g of PEI (Mw 1200 g / mol, amine number 17.9 mmol / g). The reactor was evacuated (60 mbar) and purged with nitrogen three times while the temperature was increased to 100 °C. After adding 201 g of 1-decene oxide (DO), the reactor was pressurized to 2 bar. The addition of butylene oxide (BuO) was carried out within 3.5 h (742 g). The temperature was increased to 115 °C and stirred for an additional 3 h. The reactor was then cooled to 60 °C and depressurized. Finally, the reactor was pressurized at 100 mbar for 20 min and purged with nitrogen. 3640 g of a clear, viscous liquid was obtained.

[0069] Example 11 A 5 L stainless steel reactor equipped with a stirrer was charged with 2500 g of PEI (MW 800 g / mol, amine number 18.2 mmol / g) followed by 590 g of water. The reactor was evacuated (60 mbar) and purged with nitrogen three times while the temperature was increased to 100 °C. The reactor was pressurized to 2 bar, and butylene oxide (BuO) addition was started with 152 g of BuO within 5 minutes. An additional 700 g of BuO was charged over 3 hours while stirring at 150 rpm. The temperature was increased to 120 °C and stirring continued for another 3.5 hours. The reactor was then cooled to 60 °C and depressurized. Finally, the reactor was pressurized at 100 mbar for 10 minutes and purged with nitrogen. 3933 g of a clear liquid was obtained.

[0070] Example 12 A 5 L stainless steel reactor equipped with a stirrer was charged with 2700 g of PEI (Mw 5000 g / mol, amine number 17.7 mmol / g) and 375 g of water. The reactor was evacuated (60 mbar) and purged with nitrogen three times while the temperature was increased to 100°C. After adding 293 g of 1,2-dodecene oxide (DDO), the reactor was pressurized to 2 bar. Propylene oxide (PO) was added (462 g) within 3.5 hours. The temperature was increased to 115°C and stirred for an additional 3 hours. The reactor was then cooled to 60°C and depressurized. Finally, the reactor was pressurized at 200 mbar for 10 minutes and purged with nitrogen. 3826 g of a slightly yellowish viscous liquid was obtained.

[0071] Example 13 A 2 L glass flask equipped with a stirrer and reflux funnel was charged with 500 g of polyethyleneimine (PEI, Mw 5000 g / mol, amine value 17.7 mmol / g), 342 g of water was added (300 rpm), and the mixture was heated to 50 °C while purging with nitrogen for 20 min. While maintaining the temperature at 50-65 °C, 135 g of butylene oxide (BuO) was added over 3 h, and the mixture was stirred at 60 °C overnight. The temperature was then increased to 100-105 °C while partially removing water (30 min), and the mixture was held at 100 °C for 30 min. A 40 mbar vacuum was then applied for 10 min. The resulting yellowish mixture was quenched with nitrogen and cooled to room temperature (approximately 20 °C). 825 g of a yellowish viscous liquid was obtained, which was diluted with 445 g of water to a 50% aqueous solution.

[0072] In the descriptions of Comparative Examples 1-3 and Examples 1-13, references to amine numbers relate to polyethyleneimine before alkoxylation.

[0073] [Table 1]

[0074] In Table 1, references to amine number refer to the amine number of the alkoxylated polyethyleneimine. PO means propylene oxide and BuO means butylene oxide.

[0075] The alkoxylated polyethyleneimines prepared in Examples 1 to 13 and Comparative Examples 1 to 3 were evaluated using equilibrium and absorption in a 15% CO2 mixed gas containing 5% O2 and 80% N2 at 40°C. The results are shown in Table 2.

[0076] Determination of equilibrium load with CO2 The equilibrium loading was determined in a bubble column reactor as described in [BRECHTEL, K. Einfluss der Molekuelstruktur auf die-Abtrennung mit waessrigen Aminloesungen aus Rauchgasen fossil befeuerter Kraftwerke. Dissertation / PhD, Universitaet Stuttgart, 2011; A. Schaeffer, Amine und Aminmischungen zur-Absorption ausus Kraftwerksrauchgasen und ihr Energiebedarf zur Regeneration Dissertation / PhD, Universitaet Stuttgart, 2013].

[0077] A 0.15 kg sample was diluted with 0.15 kg of water to obtain a 50% aqueous solution. The sample was heated in a water bath on an adjustable heating plate and exposed to a 2 L / min flow of synthetic flue gas with a composition of 15 vol% CO2, 5 vol% O2, and 80 vol% N2. The flue gas was injected into the sample using a mass flow controller through a glass frit (pore size 1) to achieve good mixing and a large mass transfer area. The effluent (excess) low-CO2 gas stream was fed to an infrared gas analyzer via a reflux condenser and sample gas condenser. The reflux condenser condensed evaporated water or solvent and returned it to the sample. The gas composition was continuously measured by the infrared gas analyzer and recorded via a computer interface.

[0078] The mass of the sample [kg] is in equilibrium with the CO2 concentration in the flue gas or the current CO2 partial pressure. The volume of CO2 absorbed in the solvent [m] was obtained from the integral formation over time [min]. The incoming flue gas volume flow rate [l / min] was constant. Therefore, the equilibrium load was calculated as the mass % of CO2 relative to the mass of the 50% sample solution. For this purpose, the equilibrium load was determined at a temperature of 50 °C.

[0079] All carbon dioxide absorbents employed (alkoxylated polyethyleneimine, polyethyleneimine, or ethanolamine) were employed as 50% by weight aqueous solutions in the tests.

[0080] The rotation rate (i.e., the absorption / desorption cycle) was determined primarily from the uptake / absorption rate and the desorption rate.

[0081] [Table 2]

[0082] The alkoxylated polyethyleneimines of the present invention exhibit significantly improved carbon dioxide absorption capacity compared to comparative alkoxylated polyethyleneimines and non-alkoxylated amines (ethoxylated ammonia), including monoethanolamine (MEA). The non-alkoxylated amines and ethanolamines exhibit higher total CO absorption capacities, but at much lower circulation rates (i.e., rotation rates or rates of absorption / desorption cycles) and absorption amounts per hour.

Claims

1. 1. A method of using a composition comprising an alkoxylated polyalkyleneimine for capturing a gas having a pKa greater than 5, preferably carbon dioxide, from a gas or mixture of gases, the method comprising the steps of: (a) The following: (i) a polyalkyleneimine; and (ii) alkylene oxide; providing a reaction mixture comprising: (b) carrying out the reaction of (i) the polyalkyleneimine with (ii) the alkylene oxide at a temperature of at least 50°C; and (c) optionally diluting the product of step (b); and the molar ratio of alkylene oxide to NH of the polyalkyleneimine in the reaction mixture is 0.1 to 0.35; 1. A method of use wherein the reaction mixture comprises less than 55% by weight of water, preferably less than 30% by weight of water, based on the weight of the reaction mixture, and wherein the reaction mixture comprises less than 5% by weight, preferably less than 1% by weight of a polar organic solvent, based on the weight of the reaction mixture.

2. 2. The method of claim 1, wherein the alkoxylated polyalkyleneimine is an alkoxylated polyethyleneimine, and the (i) polyalkyleneimine in step (a) is polyethyleneimine.

3. 3. The use according to claim 1 or 2, wherein the reaction mixture comprises less than 20% by weight of water, more preferably less than 10% by weight of water, based on the weight of the reaction mixture.

4. 4. The use according to any one of claims 1 to 3, wherein the reaction mixture does not contain a polar organic solvent.

5. 5. Use according to any one of claims 1 to 4, wherein the reaction mixture is solvent-free and contains water as the only reactant, suitably in an amount of not more than 1 mole per mole of NH group of the polyalkyleneimine, preferably polyethyleneimine.

6. 6. The use of any one of claims 1 to 5, wherein in step (a), the (i) polyalkyleneimine, preferably polyethyleneimine, is provided at a temperature of at least 50°C, preferably from 60°C to 140°C, more preferably from 60°C to 110°C, and the (ii) alkylene oxide is provided at a temperature of at least 50°C, preferably from 60°C to 100°C, and is combined with the (i) polyalkyleneimine, preferably polyethyleneimine, to form the reaction mixture.

7. The use according to any one of claims 1 to 6, wherein the reaction in step (b) is carried out at a temperature of from 60°C to 140°C, preferably from 80°C to 130°C.

8. The use according to any one of claims 1 to 7, wherein the reaction in step (b) is carried out at a pressure higher than 1.25 bar, preferably at a pressure between 1.5 and 3 bar.

9. 9. The method of claim 8, wherein the dilution step (c) is carried out after the reaction mixture is depressurized.

10. 10. Use according to any one of claims 1 to 9, wherein the mass ratio of the alkylene oxide to the NH of the polyalkyleneimine, preferably polyethyleneimine, in the reaction mixture is from 0.15 to 0.

32.

11. 11. The use according to any one of claims 1 to 10, wherein the alkylene oxide comprises propylene oxide and / or butylene oxide.

12. The polyalkyleneimine, preferably polyethyleneimine, in the reaction mixture has a weight average molecular weight (M Ｗ 12. The method of claim 1, wherein the compound is a hydroxybenzoate.

13. 13. Use according to any one of claims 1 to 12, wherein the polyalkyleneimine, preferably polyethyleneimine, in the reaction mixture is branched.

14. 14. Use according to any one of the preceding claims, wherein the alkoxylated polyalkyleneimine, preferably the alkoxylated polyethyleneimine, has a molar ratio of OH / NH of 0.20 to 0.

35.

15. 15. Use according to any one of the preceding claims, wherein the composition comprises <10 ppm, preferably <5 ppm, of alkylene oxide relative to the weight of alkoxylated polyalkyleneimine in the composition.

16. 16. Use according to any one of claims 1 to 15, wherein the alkoxylated polyalkyleneimine, preferably alkoxylated polyethyleneimine, is incorporated into a formulation for the direct capture of carbon dioxide.

17. 17. Use according to any one of the preceding claims, wherein the gas or mixture of gases is either atmospheric air or exhaust gas.

18. The following steps: (a) The following: (i) a polyalkyleneimine, preferably polyethyleneimine; and (ii) alkylene oxides, including propylene oxide and / or butylene oxide; providing a reaction mixture comprising: (b) carrying out the reaction of said (i) polyalkyleneimine, preferably polyethyleneimine, with said (ii) alkylene oxide at a temperature of at least 50°C; and (c) optionally diluting the product of step (b); 1. A method for preparing a composition comprising an alkoxylated polyalkyleneimine, which composition is obtainable by a method comprising: the molar ratio of alkylene oxide to NH of the polyalkyleneimine, preferably polyethyleneimine, in the reaction mixture is 0.1 to 0.35; The process wherein the reaction mixture comprises less than 55% water, preferably less than 30% water, by weight, based on the weight of the reaction mixture, and wherein the reaction mixture comprises less than 5% polar organic solvent, preferably less than 1% by weight, based on the weight of the reaction mixture.

19. 19. The method according to claim 18, comprising the features of any one of claims 2 to 10 and any one of claims 12 to 17.

20. A composition comprising an alkoxylated polyalkyleneimine obtainable by the method of claim 18.

21. 21. A composition according to claim 20, comprising the features of any one of claims 2 to 10 or any one of claims 12 to 17.

Images