Method for separating and reversibly storing chlorine gas from chlorine-containing gas and storage medium for storing chlorine gas used in said method

Abstract

The invention relates to a method for separating and storing (supporting) chloroCl2 from a Cl2-containing gas, in particular a Cl2-containing process gas, by contacting the Cl2-containing gas with at least one polymer compound of general formula (I), the at least one polymeric compound of general formula (I) comprises a polymer having at least one alkylated cationic quaternary amino moiety and each alkylated quaternary amino moiety having at least one chloride anion, where R1, R2, R3 are independently of each other a C1-C4 alkyl moiety, preferably selected from the group of methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl and sec-butyl, and where R1, R2, R3 are independently of each other a C1-C4 alkyl moiety, preferably selected from the group of methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl and sec-butyl. Wherein the R1, R2, R3 moieties may be the same or different from each other, where a, b, c are independently of each other 0, 1, 2 or 3, where the sum of a + b + c must be 3, where chlorine Cl2 from a Cl2-containing gas is bound by at least one polymer compound of general formula (I), thereby providing a polymer compound of general formula (II), where ngt; 0, preferably ngt; 1, preferably n is 1 to 4.

Description

[0001] The present invention relates to a method for separating and storing chlorine from chlorine-containing gases, a storage medium for storing chlorine used in the method, a method for releasing chlorine from the storage medium, the use of the storage medium for separating chlorine from process gases and / or for reversible absorption and storage of chlorine, and the use of the storage medium as a chlorinating agent for olefins.

[0002] describe

[0003] Chlorine is one of the most important basic chemicals in the chemical industry, and it is required to produce approximately 50% of all industrial chemicals, 30% of all agricultural chemicals, and 20% of all pharmaceuticals. The most important products in the chlorine industry are polymers such as polyvinyl chloride (PVC) or polyurethane (PU), and substances such as phosphorus trichloride, which is crucial for the synthesis of pesticides and flame retardants.

[0004] To meet global chlorine demand in 2021, approximately 92 million tons of chlorine will be produced primarily through chlor-alkali electrolysis, which involves the electrolysis of sodium chloride into chlorine gas and sodium hydroxide.

[0005] Chlorine extraction is one of the most energy-intensive processes in the chemical industry, with energy accounting for approximately 50% of production costs. Therefore, chlorine production in Germany alone requires approximately 12 million MWh, corresponding to about 2.0% of Germany's electricity consumption. Current forecasts indicate that global chlorine production will increase to approximately 119 million tons by 2028, and the electricity demand for chlorine production will also increase accordingly.

[0006] Approximately half of the chlorine produced in chlor-alkali electrolysis is converted on-site, and the other half is liquefied to make it suitable for transport. However, it is impossible to completely liquefy the chlorine using conventional industrial methods. This leaves a residual gas stream consisting of approximately 20% chlorine, 70% air, and 10% hydrogen and water vapor. This portion of chlorine that cannot be liquefied must be removed by adding sodium hydroxide; therefore, both the chlorine in the residual gas stream and the sodium hydroxide used for it are lost industrially.

[0007] On the other hand, if chlorine can be further separated from the residual gas stream and made usable, the productivity of chlorine-alkali electrolysis can be increased, thus reducing the electricity demand for chlorine production.

[0008] The established method for separating chlorine from the residual gas stream of chlor-alkali electrolysis involves passing the residual gas stream through carbon tetrachloride (CCl4). Due to the high solubility of chlorine in carbon tetrachloride at 0°C (approximately 0.18 kg Cl2 / kg CCl4) (NWTaylor, JH Hildebrand, J. Am. Chem. Soc. 1923, 45, pp. 682-694), the chlorine content of the residual gas stream can be reduced to 1%. However, this method releases approximately 4,000 tons of carbon tetrachloride into the atmosphere annually. In the atmosphere, carbon tetrachloride acts as a greenhouse gas and damages the ozone layer (KA Lokhandwala, S. Segelke, P. Nguyen, RW Baker, TT Su, I. Pinnau, Ind. Eng. Chem. Res. 1999, 38, pp. 3606-3613).

[0009] Due to the high ozone depletion potential of carbon tetrachloride, this method is strictly limited by the Montreal Protocol. Currently, only six chlor-alkali electrolysis plants worldwide still use carbon tetrachloride to absorb chlorine from residual gas streams.

[0010] Therefore, in most factories, chlorine in the residual gas stream is not separated; the residual gas stream is treated with sodium hydroxide, resulting in sodium chloride and sodium hypochlorite as waste products.

[0011] Many such membranes have been developed that exhibit greater permeability to chlorine than to air, thus enabling the separation of chlorine components from other gases in residual gas streams. However, most of these membranes show only limited stability in continuous contact with chlorine, thus limiting their industrial applicability (MS Eikeland, M.-B. Hagg, MA Brook, M. Ottøy, A. Lindbrathen, J. Appl. Polymer Sci. 2002, 85, pp. 2458-2470).

[0012] Typically, chlorine can be irreversibly chemically bonded, for example by reacting chlorine with an olefin-based organometallic casting, but the bonded chlorine cannot be used elsewhere (TJ Azbell, RM Mandel, J.-H. Lee, PJ Milner, ACS Appl. Mater. Interfaces 2022, 14, pp. 53982-53935).

[0013] WO2007109611A1 describes a method for the safe storage and transport of chlorine under environmental pressure. Chloride 1-methyl-3-ethylimidazolium Pyridine hydrochloride is preferred. Tetraalkylammonium chloride and tetraalkyl chloride are also mentioned. .

[0014] WO2012130803A1 describes a method for removing halogens from a mixture of substances (CO, CO2, N2, methyl isocyanate, and methyl bromide). Contact between an ionic liquid and chlorine or a chlorine-containing gas is carried out in a distillation column at a temperature range of ≥50°C to ≤200°C and a pressure range of ≥0.1 bar to ≤30 bar. The chlorine-containing ionic liquid is then fed into a separation unit. There, the chlorine is (partially) released under increased temperature and / or decreased pressure. The following compound class is proposed: imidazole chloride. pyridine chloride pyrrolidine chloride guanidine chloride chlorination And ammonium chloride. The preferred compound is trihexyltetradecyl chloride. 1-Benzyl-3-methylimidazolium chloride and 1-methyl-3-octylimidazole chloride Tetrabutylammonium chloride is described as an additive used to improve flowability.

[0015] WO 2019 / 215037 A1 describes a storage medium based on the ionic compounds [NEt3Me]Cl and [NEt2Me2]Cl, which is used to reversibly absorb and store chlorine from process gases and can release chlorine by changing environmental conditions. The storage system can be reused after chlorine deloading.

[0016] When chlorine gas is added to [NEt3Me]Cl, the corresponding trichloride [NEt3Me][Cl3] is formed, which is an ionic liquid at room temperature.

[0017]

[0018] Because trichloride [NEt3Me][Cl3] is an ionic liquid with a low chlorine vapor pressure, it can be handled and transported much more safely than pressurized chlorine. Furthermore, [NEt3Me][Cl3] can be used as a chlorinating agent with reactivity very similar to, and in some cases even superior to, chlorine. For example, [NEt3Me][Cl3] can be reacted with carbon monoxide to produce phosgene, an industrially important basic chemical.

[0019] However, ionic compounds such as [NEt3Me]Cl and [NEt2Me2]Cl have the disadvantage that their structure changes after chlorine absorption; that is, the ionic compounds liquefy. This hinders the processing of the chlorine-loaded ionic compounds.

[0020] Therefore, one object of the present invention is to provide a method and storage medium that allows the separation of chlorine from chlorine-containing process gases using compounds that exhibit good storage capacity for chlorine and can be used on an industrial scale.

[0021] This objective is achieved by providing a method for separating and storing chlorine gas having the features of claim 1.

[0022] Therefore, a method is provided for separating and storing (loading) chlorine (Cl2) from Cl2-containing gas, particularly Cl2-containing process gas, wherein the Cl2-containing gas is contacted with at least one polymer compound of general formula (I).

[0023] The polymer compound of at least one general formula (I) comprises a polymer having at least one alkylated cationic quaternary amino moiety and each alkylated quaternary amino moiety having at least one chloride anion.

[0024]

[0025] Where R 1 R 2 R 3 Each of the alkyl groups is independently C1-C4, preferably selected from the group consisting of methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, and sec-butyl.

[0026] Where R 1 R 2 R 3 Some parts may be the same as or different from each other.

[0027] Where a, b, and c are independent values ​​of 0, 1, 2, or 3, and the sum of a + b + c must be 3.

[0028] The chlorine Cl2 from the Cl2-containing gas is bound to at least one polymer compound of general formula (I), thereby providing a polymer compound of general formula (II).

[0029]

[0030] Where n>0, preferably n>=1, more preferably n is 1 to 4, and particularly preferably n is 1, 2, 3, or 4.

[0031] Therefore, a method is provided that not only enables the separation of chlorine from a gas mixture, but also enables the storage of chlorine in a storage medium that can be easily handled and can be used as a chlorinating agent, as discussed further below.

[0032] In one implementation of this method, R 1 R 2 R 3 The components are independently selected from the group consisting of methyl, ethyl, n-propyl, and isopropyl. In a more preferred embodiment, the polymer compound of general formula (I) is... or .

[0033] According to this method, a polymer is used to adsorb chlorine from a residual chlorine-containing gas stream. Therefore, chlorine can be recovered and used in the chlorination process. The chlorine-loaded polymer can also be used as a reagent for carrying out a chlorination reaction similar to [NEt3Me][Cl3], as shown below.

[0034] The polymer compound used in this method is a porous solid with the following advantages: its structure does not change after chlorine loading; that is, the polymer compound is a permanent solid that allows for better gas separation at lower chlorine concentrations. Furthermore, the solid polymer compound of formula (I) is easier to handle and can be used in variable ways (e.g., as a solid layer, membrane, in granular form, or as a block), making it more suitable as an absorbent material.

[0035] Specifically, by providing a Cl2-containing polymer compound of formula (II) that can be used as a Cl2 source for further synthetic applications, the polymer compound of formula (I) allows for the reversible absorption and storage of Cl2 from process gases.

[0036] Cl2 molecules bind to or interact with the alkylated cationic quaternary amino moiety and its chloride counterion, as shown in Scheme 1:

[0037]

[0038] Option 1

[0039] Due to the high reactivity of chlorine, many polymers have been found to degrade or decompose upon contact with chlorine. Therefore, only certain polymers are suitable for this method.

[0040] Suitable polymers are based on anion exchange resins. In one embodiment of this method, an anion exchange resin based on polystyrene or polyacrylate containing at least one alkylated cationic quaternary amino moiety ([resin-poly]Cl) is used. Therefore, polyacrylate-based resins are preferred. Such anion exchange resins are commercially available.

[0041] One example is the polyacrylate-based resin Lewatit TP107, which contains an alkylated quaternary amino group and a chloride anion as a counterion. This resin requires no further conditioning and can be used as a polymer according to general formula (I) without further treatment. The concentration of the active site (i.e., the alkylated quaternary amino group) is approximately 2.4 equivalents / L.

[0042] Another example is the polystyrene-based resin Amberlyst, which has an alkylated (e.g., methylated) quaternary amino group and hydroxyl ions as counterions. As will be explained in more detail later, such polymers must undergo a preconditioning step in which hydroxyl ions exchange with chloride ions to obtain a polymer according to general formula (I). The concentration of the active site (i.e., the alkylated quaternary amino group) is about 0.8 equivalents / L.

[0043] Another preferred polymer suitable for this method is a polyethyleneimine (PEI) polymer containing at least one alkylated quaternary amino group. By using polyethyleneimine (PEI) as the alkylated and crosslinked base polymer, polymers of the [PEI poly]Cl type can be synthesized. Due to the absence of functional groups, these polymer materials not only exhibit high resistance to chlorine but also very high chloride ion concentrations, which is important for achieving high chlorine absorption relative to the adsorbent mass. Here, chlorine absorption also provides a stable corresponding trichloride [PEI poly][Cl3] (Scheme 2):

[0044]

[0045] Option 2

[0046] The polyethyleneimine (PEI) polymer comprising at least one alkylated quaternary amino moiety can be obtained in a multi-step reaction process. In one embodiment, in a first step, the polyethyleneimine is reacted with a suitable crosslinking agent (e.g., a diisocyanate (e.g., 4,4'-diphenylmethane diisocyanate) or glutaraldehyde) to obtain crosslinked polyethyleneimine (PEI crosslinking step).

[0047] In the second step, the alkylating agent is mixed with the cross-linked polyethyleneimine (aminoalkylation or quaternization step). Suitable aminoalkylating agents are dialkyl sulfates (e.g., dimethyl sulfate, dialkyl ester) or methyl chloroformate.

[0048] Depending on the alkylating agent used, an optional third step is required, in which the alkylated crosslinked polyethyleneimine is conditioned with a suitable chloride anion source, such as NaCl, to exchange any anions introduced during alkylation with chloride anions, for example, by chloride exchange of sulfate anions introduced using dialkyl sulfate esters as alkylating agents, to obtain a modified polymer according to general formula I. In the context of this application, these polymers may be designated as PEI_polymer_Cl.

[0049] In another embodiment, the reaction steps are in reverse order. In the first step, polyethyleneimine is alkylated or modified with chlorocholine chloride (CCC) to provide a PEI_CCC polymer. In the second step, the PEI_CCC polymer is crosslinked with glutaraldehyde under freezing conditions to form a cryogel PEI_cryogel_Cl. CCC modification can also be performed in the final step after cryogelation. Both methods are possible and result in high Cl2 adsorption.

[0050] While ion exchange resins have the significant advantage of being commercially available, PEI-based chlorine adsorbents exhibit higher chlorine storage capacity and can be customized during synthesis in terms of their parameters (porosity, chloride ion concentration) and shape (powder, granules, pore matrix).

[0051] In a further step, a preconditioning step of the polymer of formula (I) may be required before use. For the purpose of preconditioning, the polymer of formula (I) is contacted with chlorine gas. When the polymer is contacted with chlorine gas, HCl, which also binds chloride ions, is generated. Therefore, it is advantageous to completely remove HCl from the polymer of formula (I), for example by applying a vacuum, to obtain a preconditioned polymer of formula (I) ready to be loaded with chlorine gas and used as a storage medium as in formula (II).

[0052] The polymer compound of formula (I) can be loaded with Cl2 gas by condensation or in the gas phase.

[0053] Preferably, chlorine is removed from the gas mixture by contacting the chlorine-containing process gas with the polymer compound of formula (I) which is placed in the process gas as a solid powder.

[0054] In particular, polymeric compounds of formula (I) can be used to remove chlorine from chlorine-containing process gases, thereby purifying the chlorine-containing process gases and making the chlorine subsequently usable for other purposes. Separation tasks involve removing chlorine from process gases, especially those containing H2, CO2, O2, CO, NO, NO2, N2O4, N2, SO3, and mixtures thereof.

[0055] When the polymer compound of formula (I) is loaded with Cl2 in the gas phase, the flow rate of the Cl2-containing gas is 10 l / h to 40 l / h, preferably 15 l / h to 35 l / h, more preferably 20 l / h to 30 l / h. The Cl2-containing gas can be a gas mixture consisting of chlorine and dry air, for example, an air mixture containing 5 vol% to 30 vol% Cl2 gas, preferably 10 vol% to 20 vol% Cl2 gas, more preferably 10 vol% to 15 vol% Cl2 gas. Using the gas phase, Cl2 absorption can be 20 vol% to 90 vol%, preferably 44 vol% to 90 vol%.

[0056] The polymer compound of general formula (I) is loaded with Cl2 gas at a temperature of 10°C to 40°C, preferably 20°C to 30°C, and a pressure of 0.5 bar to 1.5 bar, preferably 1 bar.

[0057] As described above, the polymer compound of formula (I) can also be loaded with Cl2 gas by condensation. For this purpose, the polymer is cooled to -196°C in a pressure flask using liquid nitrogen. A predetermined amount of chlorine is then added to the flask, and it is frozen there. The flask is then heated to room temperature.

[0058] The polymer compound of formula (I) can be loaded with at least 0.1 g Cl2 / g polymer compound, preferably at least 0.2 g Cl2 / g polymer compound, more preferably at least 0.4 g Cl2 / g polymer compound, even more preferably at least 0.5 g Cl2 / g polymer compound, even more preferably at least 0.6 g Cl2 / g polymer compound, and at most at least 0.8 g Cl2 / g polymer compound.

[0059] In one embodiment, the polymer compound of formula (I) may be loaded with 0.1 g Cl2 / g polymer compound to 1.0 g Cl2 / g polymer compound, 0.2 g Cl2 / g polymer compound to 0.7 g Cl2 / g polymer compound, 0.3 g Cl2 / g polymer compound to 0.6 g Cl2 / g polymer compound.

[0060] Under these loading conditions, different proportions of different polychlorinated anions can coexist, for example, Cl3. - Cl5 - Cl7 - And more advanced polychlorides.

[0061] The storage capacity of a polymer depends on the type of polymer (i.e., resin-poly-Cl or PEI-poly-Cl) and whether the Cl2 gas is added via the gas phase or via condensation. For example, adding Cl2 gas in the gas phase appears to provide higher Cl2 absorption.

[0062] The general Cl2 loading capacity of [resin-poly]Cl of formula (I) is from 0.1 Cl2 / g of polymer compound to 0.6 Cl2 / g of polymer compound, wherein the loading capacity of the polyacrylate-based resin (such as Lewatit TP107) is from 0.1 Cl2 / g of polymer compound to 0.2 Cl2 / g of polymer compound, while the loading capacity of the polystyrene-based resin (such as Amberlyst) is from 0.4 Cl2 / g of polymer compound to 0.6 Cl2 / g of polymer compound.

[0063] The general Cl2 loading capacity of [PEI-poly]Cl of formula (I) is from 0.15 g Cl2 / g of polymer compound to 0.9 g Cl2 / g of polymer compound, wherein the loading capacity of PEI_polymer_Cl is from 0.15 Cl2 / g of polymer compound to 0.3 Cl2 / g of polymer compound, while the loading capacity of PEI_cryogel_Cl is from 0.6 Cl2 / g of polymer compound to 0.9 Cl2 / g of polymer compound.

[0064] In another aspect of the present invention, the above method provides a storage medium for storing chlorine gas Cl2, wherein the storage medium comprises a polymer compound of formula (II)

[0065]

[0066] where R 1 、R 2 、R 3 are independently of each other a C1-C4 alkyl moiety, preferably selected from the group consisting of methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl and sec-butyl,

[0067] where R 1 、R 2 、R 3 moieties may be the same or different from each other,

[0068] where a, b, c are independently of each other 0, 1, 2 or 3, wherein the sum of a + b + c must be 3,

[0069] where n > 0, preferably n >= 1, more preferably n is from 1 to 4, particularly preferably n is 1, 2, 3, 4.

[0070] As mentioned, n can be > 0 (i.e., any number greater than 0). For example, if n is 0 < n < 1, then and a mixture of is present in the storage medium. In such a case, n can be, for example, 0.8, as in 中。

[0071] The storage medium of formula (II) (under load) contains at least 0.1 g Cl2 / g polymer compound, preferably at least 0.2 g Cl2 / g polymer compound, more preferably at least 0.4 g Cl2 / g polymer compound, even more preferably at least 0.5 g Cl2 / g polymer compound, even more preferably at least 0.6 g Cl2 / g polymer compound, and at most at least 0.8 g Cl2 / g polymer compound. As mentioned above, the amount of Cl2 absorbed depends on the type of polymer.

[0072] The stored chlorine can be removed from the chlorine-loaded storage medium of formula (II), thereby obtaining the deloaded polymeric chlorine adsorbent of formula (I) again.

[0073] Therefore, in another aspect of the invention, a method is provided for releasing chlorine gas Cl2 from a storage medium containing a polymer compound of formula (II), wherein the chlorine gas Cl2 stored in the storage medium is released by increasing the temperature of the storage medium to 60°C, preferably to 80°C, and / or by reducing the partial pressure above the storage medium, for example by applying a vacuum.

[0074] In this way, 50% to 95%, preferably 60% to 95%, of the stored chlorine gas Cl2 is released. The cycle of storing (loading) and releasing (unloading) chlorine gas Cl2 can be repeated at least 5 times, preferably at least 7 times.

[0075] The deloading of the (reversible) storage medium is carried out at a temperature ranging from ≥20°C to ≤80°C, preferably from ≥30°C to ≤70°C, and more preferably from ≥40°C to ≤60°C. Cl2 release can optionally be initiated by reducing the partial pressure, particularly by applying a vacuum.

[0076] Therefore, in another aspect of the invention, the storage medium of formula (II) can be used to separate Cl2 from process gas and / or to reversibly absorb and store Cl2 from process gas.

[0077] However, the storage medium of formula (II) can also be used as a chlorinating agent, for example, for the chlorination of at least one olefin, thereby providing

[0078] - At least one chlorinated alkane, and

[0079] - Polymer compounds according to formula (I).

[0080] Therefore, the chlorine-loaded polymer storage medium of formula (II) can be used as a chlorinating agent for chlorination to olefins (see Scheme 3).

[0081]

[0082] This allows for the recovery of the deloaded chloropolymer adsorbed compound of formula (I).

[0083] Overall, the polymer-based chlorine adsorbent of formula (I) offers great potential for the safe and simple adsorption, storage, and conversion of chlorine from residual gas streams. In the future, chlorine production can therefore become more efficient, environmentally friendly, and resource-saving.

[0084] The invention will now be described in more detail by way of example with reference to the accompanying drawings. It shows:

[0085] Figure 1 Raman spectra of Amberlyst A26(Cl) before and after chlorine loading. The band highlighted in yellow indicates the [Cl] used for loading and storage. n ] - The presence of anions.

[0086] Figure 2 Raman spectra of cPEI_Cl polymer before and after chlorine loading. The band highlighted in yellow indicates the [Cl] used for loading and storage. n ] - The presence of anions.

[0087] Figure 3 Raman spectra of the cryogel-Cl polymer before and after loading with chlorine. The bands highlighted in yellow indicate the [Cl] used for loading and storage. n ] - The presence of anions.

[0088] Figure 4 The reaction mixture after chlorination of ethylene using a loaded storage material. 1 H-NMR (400 MHz, CDCl3, 20°C).

[0089] Figure 5 The reaction mixture after chlorination of ethylene using a loaded storage material. 13 C-NMR (100 MHz, CDCl3, 20°C).

[0090] Figure 6 Chlorine is absorbed from the residual gas stream by Amberlyst A26 (Cl) as a function of time.

[0091] Figure 7 A device for chlorine absorption from residual gas streams.

[0092] Figure 8 Relative UV / Vis absorbance of the gas mixture as a function of time. Decreased absorbance indicates a decrease in chlorine concentration.

[0093] Figure 9 SEM image of cPEI-MDI-DMS-2Cl.

[0094] Figure 10 SEM image of cPEI-MDI-DES-2Cl.

[0095] Figure 11 SEM image of chloroformate methylated cPEI-MDI.

[0096] Figure 12 SEM images of protonated cPEI-MDI using HCl.

[0097] Figure 13 SEM image of PEI cryogel Cl at 30x magnification.

[0098] Figure 14 SEM image of PEI cryogel Cl at 150x magnification.

[0099] Figure 15 IR spectrum of commercial PEI.

[0100] Figure 16 IR spectrum of PEI-CCC.

[0101] Figure 17 Commercial PEI (left) and PEI-CCC (right) in D2O 1 H-NMR.

[0102] Figure 18 Commercial PEI (left) and PEI-CCC (right) in D2O 13 C-NMR.

[0103] Figure 19 TGA curve of PEI cryogel Cl.

[0104] Polymers used for chlorine storage:

[0105] Commercially available anion exchange resins Lewatit TP107 and Amberlyst A26 (Cl) were used, along with synthesized PEI-based polymers PEI_polymer_Cl (cPEI_Cl) and PEI_cryogel_Cl (cryogel_Cl) (see the synthesis protocol below).

[0106] The polymer materials (Lewatit TP107, Amberlyst A26(Cl), PEI_polymer_Cl (cPEI_Cl), PEI_cryogel_Cl (cryogel_Cl)) were dried, and then chlorine was slowly added to pre-condition the polymer. The mixture was left overnight, and the chlorine was removed under high vacuum to obtain the pre-conditioned chlorine storage medium.

[0107] Chlorine can be stored by condensation or by adding chlorine to a pre-conditioned polymer via the gas phase.

[0108] By applying a vacuum and heating to 60°C for 5 hours, 60% (PEI cryogel) to 95% (Amberlist A26(Cl)) of the stored chlorine was released. This storage loading and unloading was performed more than 7 times without a significant reduction in the amount of chlorine stored and released.

[0109] Table 1 shows the determined storage capacities of different polymers. These were determined by Raman spectroscopy (…). Figures 1 to 3 Characterizing the polymer material indicates that polychlorinated anions ([Cl(Cl2)]) were formed during the loading of the stored material. n ] – (n=1 to 4).

[0110] Table 1. Storage capacity of polymers in g chlorine / g chlorine storage medium

[0111]

[0112] Chlorination of ethylene using Amberlyst A26 ([Cl3]) :

[0113]

[0114] Option 4: Synthesize 1,2-dichloroethane using Amberlyst A26 ([Cl3]).

[0115] The loaded storage medium (Amberlyst A26 ([Cl3]; 13.2 mmol, 0.940 g stored chlorine)) was added to the flask. Subsequently, excess ethylene was added. The decolorization of the resin and the formation of a liquid within the flask were observed. 1 H-NMR spectroscopy and 13 C-NMR spectroscopy (see C-NMR spectroscopy) Figure 4 and Figure 5 The obtained liquid was characterized by a method that revealed the presence of 1,2-dichloroethane as the sole product.

[0116]

[0117]

[0118] Separating chlorine from a chlorine / air mixture

[0119] A gas mixture consisting of 12.5% ​​chlorine and 87.5% dry air was passed through a PFA (perfluoroalkoxyalkane) U-tube filled with Amberlyst A26(Cl) (15.95 g) at a flow rate of 25 L / h (corresponding to 0.83 g / min). The chlorine absorption through the Amberlyst was observed using a balance. Figure 6 A total of 20% of the chlorine passing through the system is absorbed.

[0120] A peristaltic pump is used to circulate a gas mixture consisting of 15% chlorine and 85% dry air through a U-shaped tube filled with chlorine storage material. Figure 7 The chlorine content of the system was monitored using UV / Vis spectroscopy and by weighing the stored material after the experiment. Circulating the gas mixture for 115 to 250 minutes resulted in the absorption of 44% to 90% of the chlorine present in the system. Figure 8 ).

[0121] Synthesis of PEI polymer Cl

[0122] 1.1 PEI crosslinking

[0123] 1.1.1 4,4'-Diphenylmethane diisocyanate (MDI)

[0124]

[0125] cPEI-MDI-2

[0126] bPEI (10 g, branched polyethyleneimine, MW 10,000, catalog number: 19850, 10 g) was dissolved in dichloromethane (DCM) (75 mL) under continuous stirring. MDI (2 mol%) was dissolved in DCM (4 mL) and added to the reaction mixture over a 4-hour period. The reaction mixture was stirred overnight and quenched with H2O (10 mL). The product was washed with MeOH (200 mL) and H2O (200 mL) in a centrifuge. After freeze-drying, a white powder product (1.9 g) was obtained.

[0127] cPEI-MDI-10 (enlarged)

[0128] bPEI (50 g) was dissolved in DCM (500 mL) with continuous stirring. MDI (10 mol%) was dissolved in DCM (150 mL) and added to the reaction mixture over a 3-hour period. The reaction mixture was stirred overnight and quenched with H2O (200 mL). The product was washed with MeOH (500 mL) and H2O (500 mL) in a centrifuge. The product was lyophilized overnight. A white powder product was obtained after lyophilization.

[0129]

[0130]

[0131] 1.1.2 Glutaraldehyde

[0132]

[0133] cPEI-Glut-10

[0134] PEI (1 g) was dissolved in H₂O (10 mL) with continuous stirring. Glutaraldehyde (10 mol%, 50% solution in water) was added to the reaction mixture. The reaction was carried out overnight at room temperature. Formic acid (5 mL) was added, and the solution was heated to 70 °C and stirred overnight. The product was washed with H₂O (200 mL) in a centrifuge and then freeze-dried overnight to obtain an orange spongy powder (0.67 g).

[0135]

[0136]

[0137] cPEI-Glut-20

[0138] PEI (1 g) was dissolved in H₂O (10 mL) with continuous stirring. Glutaraldehyde (20 mol%, 50% solution in water) was added to the reaction mixture. The reaction was carried out overnight at room temperature. Formic acid (5 mL) was added, and the solution was heated to 70 °C and stirred overnight. The product was washed with H₂O (200 mL) in a centrifuge and then freeze-dried overnight to obtain an orange spongy powder (1.22 g).

[0139]

[0140]

[0141] 1.2 Quaternization

[0142] 1.2.1 Dialkyl sulfate

[0143] cPEI-MDI-DMS-1Cl /

[0144]

[0145] cPEI-MDI-10 (5 g) was mixed with dimethyl sulfate (DMS) or diethyl sulfate (DES) (20 equivalents, based on PEI-monomer) and K2CO3 (0.5 equivalents). The reaction was carried out at room temperature for 3 days. The alkyl sulfate was neutralized with NH3- solution (25%) under ice cooling. The product was washed with H2O (200 mL) and stirred overnight in saturated NaCl solution (400 mL). Afterward, the product was washed again with H2O (200 mL) and dried overnight under freeze-drying to obtain a white powder.

[0146]

[0147]

[0148] cPEI-MDI-DMS-2Cl ( Figure 9 )

[0149] Repeat the procedure used for cPEI-MDI-DMS-1Cl.

[0150]

[0151]

[0152] cPEI-MDI-DES-1Cl

[0153]

[0154] The procedure described for cPEI-MDI-DMS-1Cl was performed using diethyl sulfate (20 equivalents, based on PEI-monomer) instead of dimethyl sulfate.

[0155]

[0156]

[0157] cPIE-MDI-DES-2Cl ( Figure 10 )

[0158] Repeat the procedure used for cPEI-MDI-DES-1Cl.

[0159]

[0160]

[0161] 1.2.2 Methyl chloroformate

[0162]

[0163] Methyl chloroformate (4 equivalents) in 10 mL of DCM was added dropwise to a slurry of cPEI-MDI-10 (5 g) and DCM (50 mL) at -15 °C. The reaction was warmed and stirred overnight. Afterward, the reaction was heated for 3 hours. The product was dried under reduced pressure to obtain a white powder. Figure 11 ).

[0164]

[0165]

[0166] 1.2.3 Hydrochloric acid

[0167]

[0168] cPEI-MDI-10 (5 g) was mixed with HCl (1 M, 460 mL, based on 4.0 equivalents of PEI-monomer) and stirred overnight at room temperature. The product was washed with H2O (200 mL) and lyophilized overnight to obtain a white powder. Figure 12 ).

[0169]

[0170]

[0171] Synthesis of PEI cryogel Cl

[0172] 1.3 Synthesis Strategy

[0173]

[0174] Scheme 1. General synthetic route for synthesizing PEI-CCC polymer and PEI_cryogel_Cl (cryogel_Cl)

[0175] The synthetic strategy for cryogel fabrication consists of two main synthetic steps. First, PEI is modified with chlorocholine chloride (CCC) by heating in ethanol at 50°C for 24 hours. An equimolar amount of triethylamine is used to neutralize the HCl generated during the reaction.

[0176] After obtaining the PEI derivative (PEI-CCC), the cryogel was synthesized as described in the experimental section.

[0177] 1.4 Synthesis of PEI-CCC

[0178] PEI (15.0 g, 0.348 mmol) was dissolved in ethanol (350 mL). Chlorocholine chloride (72.6 g, 0.459 mmol) and triethylamine (46.5 g, 0.459 mmol) were added to the solution. The mixture was heated to 60 °C and maintained at that temperature for 16 hours. The mixture was then cooled to room temperature, and the solvent was removed by rotary evaporation. The crude product was dissolved in water (500 mL) and purified by tangential flow filtration. The pure polymer was dried by lyophilization to obtain 26.69 g of the final product as a brown solid. Figure 16 ).

[0179] 1.5 Cryogel Synthesis

[0180] Solutions of PEI-CCC (2 wt% (m / v)) and glutaraldehyde (2.5 wt% (m / v)) were prepared. Both solutions were pre-cooled to 0-1°C to prevent cross-linking before freezing. Then, the PEI-CCC solution (4 g, 200 mL) and the glutaraldehyde solution (1.36 g, 54.5 mL) were mixed and vigorously stirred at this temperature until homogenized. The resulting solution was poured into an aluminum pan (64 mm diameter, 28 mL volume) and placed in a freezer at -18°C. The mixture was held at this temperature for 24 hours. Subsequently, the formed discs were thawed to room temperature and the remaining solution was decanted. A solution of NaBH4 (2 g NaBH4, 2.1 g NaHCO3, and 0.41 g NaOH in 1 L H2O) was added to the cryogel to reduce the formed imine to the corresponding amine. The solution was then replaced three times over a 2-hour period. The cryogel was then washed with deionized water until the pH reached 7. Finally, the cryogel was freeze-dried using lyophilization. Figure 13 , Figure 14 , Figure 19 ).

[0181] Elemental analysis

[0182] CHN elemental analysis was performed using two parallel measurements on an Elementar Vario EL machine.

[0183] Quantitative analysis of chloride by mercury titration

[0184] The concentration of chloride ions in the adsorbent material was quantified using the MQuant Chloride Assay Kit 1.11106.0001 from Supelco (Merck KGaA). Titration was performed according to the kit's procedure. Each adsorbent was diluted (10.0 ± 0.3) mg with MilliQ water (5.00 mL). After adding two drops of the indicator 1,5-diphenylcarbazone in a solution containing N,N'-dimethylacetamide, the solution turned blue. The aqueous mixture containing the adsorbent material was then acidified with nitric acid solution until the color turned yellow. The yellow mixture was titrated with mercuric(II) nitrate solution. The equivalence point was indicated by the color change from yellow to purple.

[0185] Scanning electron microscopy

[0186] Scanning electron microscopy was performed on a Hitachi SU8030. The sample was adhered to a copper strip and sputtered with gold (5 nm) using a compact coating unit (CCU-010) from Safematic. An accelerating voltage of 15 mV and a current of 10 μA were used for the electron beam. The beam, instrument, and X and Y axes were adjusted to minimize image movement. Images of 1280 × 960 pixels were recorded.

Claims

1. A method for separating and storing (loading) chlorine (Cl2) from a Cl2-containing gas, particularly a Cl2-containing process gas, by contacting a Cl2-containing gas with at least one polymer compound of general formula (I). The polymer compound of at least one general formula (I) comprises a polymer having at least one alkylated cationic quaternary amino moiety and each alkylated quaternary amino moiety having at least one chloride anion. Where R 1 R 2 R 3 Each of the alkyl groups is independently C1-C4, preferably selected from the group consisting of methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, and sec-butyl. Where R 1 R 2 R 3 Some parts may be the same as or different from each other. Where a, b, and c are independent values ​​of 0, 1, 2, or 3, and the sum of a + b + c must be 3. The chlorine Cl2 from the Cl2-containing gas is bound to at least one polymer compound of general formula (I) to provide a polymer compound of general formula (II). Where n>0, preferably n>=1, and more preferably n is 1 to 4.

2. The method according to claim 1, characterized in that, The polymer is an anion exchange resin containing at least one alkylated cationic quaternary amino moiety, preferably a polystyrene- or polyacrylate-based resin, more preferably a polyacrylate-based resin.

3. The method according to claim 1, characterized in that, The polymer is a polyethyleneimine (PEI) polymer containing at least one alkylated quaternary amino group.

4. The method according to any one of the preceding claims, characterized in that, R 1 R 2 R 3 They are independently selected from the group consisting of methyl, ethyl, n-propyl, and isopropyl.

5. The method according to any one of the preceding claims, characterized in that, The polymer compound of general formula (I) is or .

6. The method according to any one of the preceding claims, characterized in that, The polymer compound of general formula (I) is loaded with Cl2 gas by condensation or in the gas phase.

7. The method according to any one of the preceding claims, characterized in that, During the loading of the polymer compound of formula (I) with Cl2 in the gas phase, the flow rate of the Cl2-containing gas is 10 l / h to 40 l / h, preferably 15 l / h to 35 l / h, and more preferably 20 l / h to 30 l / h.

8. The method according to any one of the preceding claims, characterized in that, The polymer compound of general formula (I) is loaded with Cl2 gas at a temperature of 10°C to 40°C, preferably 20°C to 30°C, and a pressure of 0.5 bar to 1.5 bar, preferably 1 bar.

9. The method according to any one of the preceding claims, characterized in that, The polymer compound of the general formula (I) is loaded with at least 0.1 g Cl2 / g polymer compound, preferably at least 0.2 g Cl2 / g polymer compound, more preferably at least 0.4 g Cl2 / g polymer compound, even more preferably at least 0.5 g Cl2 / g polymer compound, even more preferably at least 0.6 g Cl2 / g polymer compound, and at most at least 0.8 g Cl2 / g polymer compound.

10. A storage medium for storing chlorine gas (Cl2) obtainable by means of the method according to any one of the preceding claims, wherein the storage medium comprises a polymer compound of general formula (II). Where R 1 R 2 R 3 Each of the alkyl groups is independently C1-C4, preferably selected from the group consisting of methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, and sec-butyl. Where R 1 R 2 R 3 Some parts may be the same as or different from each other. Where a, b, and c are independent values ​​of 0, 1, 2, or 3, and the sum of a + b + c must be 3. Where n>0, preferably n>=1, and more preferably n is 1 to 4.

11. The storage medium according to claim 10, characterized in that, The polymer compound of general formula (II) (in the loaded state) contains at least 0.1 g Cl2 / g polymer compound, preferably at least 0.2 g Cl2 / g polymer compound, more preferably at least 0.4 g Cl2 / g polymer compound, even more preferably at least 0.5 g Cl2 / g polymer compound, even more preferably at least 0.6 g Cl2 / g polymer compound, and at most at least 0.8 g Cl2 / g polymer compound.

12. The use of the storage medium according to any one of claims 10 to 11 for separating Cl2 from process gas and / or for reversibly absorbing and storing Cl2 from process gas.

13. Use of the storage medium according to claim 12 for removing chlorine from process gases containing H2, CO2, O2, CO, NO, NO2, N2O4, N2, SO3, and mixtures thereof.

14. The storage medium according to any one of claims 9 to 10 is used for chlorinating at least one olefin, thereby providing at least one chlorinated alkane and a polymer compound according to formula (I) as defined in claim 1.

15. A method for releasing chlorine gas (Cl2) from a storage medium comprising a polymer compound of general formula (II) according to any one of claims 9 to 10, characterized in that, - The chlorine gas Cl2 stored in the storage medium is released by raising the temperature of the storage medium to 60°C and / or by reducing the partial pressure above the storage medium.

16. The method according to claim 15, characterized in that, The chlorine gas Cl2 stored in the storage medium is released at a temperature ranging from ≥20°C to ≤80°C, preferably from ≥30°C to ≤70°C, and more preferably from ≥40°C to ≤60°C.

17. The method according to any one of claims 15 to 16, characterized in that, The stored chlorine gas Cl2 is released at the temperature by 50% to 95%, preferably 60% to 95%.

18. A method comprising storing (loading) chlorine Cl2 in a polymer compound of formula (I) according to at least one of claims 1 to 9 and providing a storage medium comprising a polymer compound of formula (II) and releasing (deloading) chlorine Cl2 from the storage medium according to one of claims 15 to 17.

19. The method according to claim 18, characterized in that, The cycle of storing (loading) chlorine gas Cl2 in a polymer compound of formula (I) and providing a storage medium containing a polymer compound of formula (II) can be repeated at least 5 times, preferably at least 7 times.

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