Highly selective and highly CO2 plasticization-resistant polymer membranes for gas separation

Abstract

Highly selective and highly CO2 plasticization resistant polymers for gas separation applications comprising a plurality of repeating units of formula (I). The polymers may be synthesized from a super acid catalyzed poly(hydroalkylation) reaction. Membranes made from the polymers and gas separation processes using membranes made from the polymers are also described. [Formula 1] JPEG2024538149000068.jpg8170

Description

[Technical Field]

[0001] (Priority statement) This application claims priority to U.S. Provisional Patent Application No. 63 / 262,906, filed October 22, 2021, which is incorporated herein by reference in its entirety. [Background technology]

[0002] Over the past 40-45 years, the state-of-the-art of polymer membrane-based gas separation processes has developed rapidly. Membrane-based technologies offer the advantages of low capital costs and high energy efficiency compared to traditional separation methods. Membrane gas separation is of particular interest to oil producers and refiners, chemical companies, and industrial gas suppliers. Several applications of membrane gas separation have achieved commercial success, including N enrichment from air, carbon dioxide removal from natural gas and enhanced oil recovery, and hydrogen removal from nitrogen, methane, and argon in ammonia purge gas streams. For example, UOP's Separex™ spiral-wound polymer membrane technology is currently the international market leader for carbon dioxide removal from natural gas.

[0003] Polymers offer a range of properties important for gas separation, including low cost, permeability, mechanical stability, and ease of processing. Glassy polymers (i.e., polymers at temperatures below their Tg) have a more rigid polymer backbone, thus allowing smaller molecules such as hydrogen and helium to pass through more rapidly, while larger molecules such as hydrocarbons pass through more slowly compared to polymers with less rigid backbones. Cellulose acetate (CA) glassy polymer membranes are widely used in gas separation. Currently, such CA membranes are used for natural gas upgrading, including carbon dioxide removal. While CA membranes have many advantages, they have limitations in several properties, including selectivity and permeability, as well as chemical, thermal, and mechanical stability. High-performance polymers, such as polyimide (PI), have been developed to improve membrane selectivity, permeability, and thermal stability. These polymer membrane materials have shown promising intrinsic properties for the separation of gas pairs such as CO2 / CH4, O2 / N2, H2 / CH4, He / CH4, and propylene / propane (C3H6 / C3H8).

[0004] The most commonly used membranes in commercial gas and liquid separation applications are asymmetric polymer membranes, which have a thin, nonporous, selective skin layer that performs the separation. Separation is based on a solution-diffusion mechanism, which involves molecular-scale interactions between the permeating gas and the membrane polymer. This mechanism assumes that in a membrane with two opposing surfaces, each component is adsorbed by the membrane at one surface, transported by the gas concentration gradient, and desorbed at the opposing surface. According to this solution-diffusion model, membrane performance in separating a given gas pair (e.g., CO2 / CH4, O2 / N2, H2 / CH4) can be determined by two parameters: the permeability coefficient (hereafter referred to as permeability or P A ) and selectivity (α A / B ) is determined by P A is the product of the gas flux and the thickness of the selective skin layer of the membrane divided by the pressure difference across the membrane. A / B is the ratio of the permeability coefficients of the two gases (α A / B =P A / P B ), P Ais the permeability of the more permeable gas, and P B is the permeability of the less permeable gas. A gas can have a high permeability coefficient due to a high solubility coefficient, a high diffusion coefficient, or both. Generally, the larger the molecular size of the gas, the smaller the diffusion coefficient and the larger the solubility coefficient. In high performance polymer membranes, both high permeability and selectivity are desirable because higher permeability reduces the size of the membrane area required to process a given volume of gas, thereby reducing the capital cost of the membrane unit, and higher selectivity results in higher purity product gas.

[0005] One of the components to be separated by the membrane must have a sufficiently high permeance under favorable conditions, or a very large membrane surface area is required to allow separation of a large amount of material. Gas Permeation Units (GPU, 1 GPU = 10 -6 cm 3 (STP) / cm 2 Permeance, measured in s (cm Hg), is the pressure-normalized flux and is equal to the permeability divided by the membrane skin thickness. Commercially available gas separation polymer membranes, such as CA membranes and polysulfone membranes formed by phase inversion and solvent exchange methods, have an asymmetric integral skin membrane structure. Such membranes are characterized by a thin, dense, selectively semipermeable surface "skin" and a low-density, void-containing (or porous), nonselective support region, with pore sizes ranging from large in the support region to very small adjacent to the "skin." However, fabrication of defect-free, highly selective asymmetric integral skin polyimide membranes is challenging. The presence of nanopores or defects in the skin layer reduces membrane selectivity. High shrinkage of polyimide membranes on fabric substrates during the membrane casting and drying process can lead to failure in fabricating asymmetric integral skin polyimide membranes using phase inversion techniques.

[0006] New high-performance polymers, such as polyimide (PI), poly(trimethylsilylpropyne) (PTMSP), and polytriazole, have been developed to combine high selectivity and permeability with high thermal stability. These new polymer membrane materials have shown promising properties for the separation of gas pairs such as CO2 / CH4, O2 / N2, H2 / CH4, and C3H6 / C3H8. However, gas separation processes based on glassy polymer membranes often suffer from plasticization of the rigid polymer matrix by adsorbed permeant molecules such as CO2 or C3H6. Polymer plasticization is manifested by swelling of the membrane structure and by a significant increase in permeance and a decrease in selectivity for all components in the feed above the plasticization pressure when the feed gas mixture contains condensable gases. Plasticization is particularly problematic for gas fields containing high CO2 concentrations and heavy hydrocarbons, as well as for systems requiring two-stage membrane separation.

[0007] U.S. Patent Application Publication Nos. 2005 / 0268783(A1), 2009 / 0182097(A1), and 2009 / 0178561(A1) disclosed chemically crosslinked polyimide hollow fiber membranes prepared by a two-step process. Step 1 is the synthesis of a monoesterified polyimide polymer in solution by treating a polyimide polymer containing carboxylic acid functional groups with a small diol molecule under esterification conditions in the presence of dehydration. However, a significant excess of diol was used to prevent the formation of a bisesterified polyimide polymer. Step 2 is the solid-state transesterification of the monoesterified polyimide membrane at elevated temperatures to form a crosslinked polyimide membrane.

[0008] Chemical cross-linking of polyimides using small diamine molecules has also been reported (Chemical cross-linking modification of polyimide membranes for gas separation, J. Membr. Sci., 2001, 189, 231-239). However, CO2 permeability was significantly reduced after this type of cross-linking. In addition, the thermal and hydrolytic stability of diamine-cross-linked polyimides were not improved.

[0009] Koros et al. reported decarboxylation-induced thermally crosslinked polyimide membranes. (Plasticization-resistant hollow fiber membranes for CO₂ / CH₄ separation based on a thermally crosslinkable polyimide, J. Membr. Sci., 2011, 382, ​​212-221) However, the decarboxylation reaction between carboxylic acid groups on the carboxylic acid-containing polyimide membrane occurred at temperatures higher than the glass transition temperature of the polyimide polymer. High temperatures resulted in densification of the membrane substructure and a decrease in membrane permeance.

[0010] No. 7,485,173 disclosed a mixed matrix membrane cross-linked using ultraviolet (UV) radiation. The cross-linked mixed matrix membrane comprises a porous material dispersed in a continuous UV-cross-linked polymer matrix.

[0011] U.S. Patent Nos. 4,931,182 and 7,485,173 disclose polyimide membranes that are physically crosslinked using UV irradiation. The crosslinked membranes have shown improved selectivity for gas separation. However, it is difficult to control the degree of crosslinking in the thin selective layer of asymmetric gas separation membranes using UV radiation, resulting in very low permeance, although the selectivity is usually very high.

[0012] Therefore, there remains a need for high performance and high stability polymeric materials and membranes for the development of gas separation membrane technology. [Brief explanation of the drawings]

[0013] [Figure 1] FIG. 1 is a diagram of one embodiment of the synthesis of poly(TP-DHB-1-1-isatin) polymer. [Figure 2] FIG. 1 is a diagram of one embodiment of the synthesis of poly(TP-DHB-1-3-isatin-TFAP-4-1) polymer. [Figure 3] 1 is a graph showing the effect of applied CO pressure on the relative CO permeability of different membranes at 50° C. DETAILED DESCRIPTION OF THE INVENTION

[0014] The use of membranes for the separation of both gases and liquids is a growing technological field with potentially high economic rewards due to low energy requirements and the scalability of modular membrane designs. Advances in membrane technology, along with the continued development of new membrane materials and new methods for the production of high-performance membranes, will make this technology even more competitive with traditional, energy-intensive and expensive processes such as distillation. Applications for commercial gas separation membrane systems include nitrogen enrichment, oxygen enrichment, hydrogen recovery, hydrogen sulfide and carbon dioxide removal from natural gas, biogas purification to remove acid gases, and air and natural gas dehydration. Various hydrocarbon separations are also potential applications for suitable membrane systems. Membranes used in these applications must possess high selectivity, durability, and productivity to be economically successful. Several applications of membrane gas separation have achieved commercial success, including nitrogen enrichment from air, carbon dioxide removal from natural gas and biogas, and enhanced oil recovery. The United States produces over 70 million tons of organic waste annually. Organic waste generates large amounts of methane upon decomposition. Methane is a potent greenhouse gas, absorbing 86 times more heat than CO2 over a 20-year period. To reduce greenhouse gas emissions and the risk of contamination of waterways, organic waste can be removed and used to produce biogas, a renewable energy source. The United States currently has 2,200 operating biogas systems, representing less than 20 percent of its total potential. Biogas feedstocks include food waste, landfill gas, livestock waste, wastewater treatment, and crop residues, and typically contain 30–40% CO2. CO2 capture from flue gas is expected to play an important role in reducing greenhouse gas emissions and mitigating global climate change. Membrane technology can be used alone or in conjunction with other gas processing technologies to remove CO2 and H2S from pretreated biogas to produce purified renewable natural gas, as well as to capture CO2 from flue gas.

[0015] The present invention discloses new types of highly selective and highly CO2 plasticization-resistant polymers and membranes for gas separation, such as H2 recovery, helium recovery, biogas purification, CO2 removal from natural gas, and air separation, as well as methods for making and using these membranes. In addition, this type of polymer with phenolic hydroxyl groups has high potential for the development of functional membranes for other applications, such as energy storage, electrolysis, and fuel cell applications.

[0016] The highly selective and highly CO2-resistant polymers have a hydrophobic polymer backbone that provides the polymer with high chemical stability, isatin-based moieties that increase the polymer's rigidity and free volume, and hydrophilic phenolic hydroxyl groups on the polymer side chains that can form H-bonds. Therefore, membranes prepared from these polymers have high chemical and thermal stability, high mechanical stability, high gas permeability, high selectivity, and high CO2-resistant properties for gas separation.

[0017] The highly selective and highly CO2 plasticization-resistant polymers contain multiple repeat units of formula (I), such as poly(aryl-biphenyl-isatin) polymers, for gas separation applications. The polymers containing multiple repeat units of formula (I) were synthesized from a superacid-catalyzed poly(hydroalkylation) reaction.

[0018] [ka] In the formula, Ar1 is

[0019] [ka] and mixtures thereof; Ar2 is

[0020] [ka] and mixtures thereof; X1 is

[0021] [ka] or

[0022] [ka]

[0023] [ka] The compound is selected from the group consisting of a mixture of one or more of:

[0024] R1~R 36 are each independently hydrogen, halogen, an alkyl group, an alkenyl group, an alkynyl group, or an aryl group. The alkyl group, the alkenyl group, the alkynyl group, or the aryl group may be substituted with a halogen.

[0025] R 37 ~R 40 are each independently a hydrogen atom, an alkyl group, an alkenyl group, an alkynyl group, or an aryl group. The alkyl group, the alkenyl group, the alkynyl group, or the aryl group may be substituted with a halogen atom.

[0026] R 41 is an alkyl group, an alkenyl group, an alkynyl group, or an aryl group. The alkyl group, the alkenyl group, the alkynyl group, or the aryl group may be substituted with a halogen.

[0027] Halogen is F, Cl, Br, or I; A1, A2, and A3 are each independently O, S, or NH; m is an integer from 5 to 5000; n is an integer from 0 to 5000; the molar ratio of n / m is in the range of 0:1 to 20:1; p is 1, 2, 3, or 4; q is 0, 1, 2, or 3; and r, s, t, and o are independently 0, 1, 2, or 3.

[0028] In some embodiments, Ar1 is

[0029] [ka] and mixtures thereof; In the formula, R 25 , R 26 , R 27 , and R 28 are each independently -H or -CH3; p is 1 or 2; q is 0 or 1.

[0030] In some embodiments, Ar2 is

[0031] [ka] and mixtures thereof; In the formula, R 29 , R 30 , R 31 , R 32 , R 33 , R 34 , R 35 , and R 36 are each independently -CH3 or -CF3, r, s, t, and o are each independently 0 or 1.

[0032] In some embodiments, X1 is

[0033] [ka] where R 37 , R 38 , and R 39are each independently -H, -CH3, -CH2CH3, -CH(CH3)2, -C(CH3)3, -CH2-C6H5, or -CH2-CH(CH3)2.

[0034] In some embodiments, X1 is

[0035] [ka] where R 37 , R 38 , and R 39 are each independently -H, -CH3, -CH2CH3, -CH(CH3)2, -C(CH3)3, -CH2-C6H5, or -CH2-CH(CH3)2; R 41 is -CH3, -CH2CH3, or -C6H5.

[0036] In some embodiments, X1 is

[0037] [ka] where R 37 , R 38 , R 39 , and R 40 are each independently -H, -CH3, -CH2CH3, -CH(CH3)2, -C(CH3)3, -CH2-C6H5, or -CH2-CH(CH3)2.

[0038] In some embodiments, X1 is

[0039] [ka] where R 37 , R 38 , R 39 , and R 40are each independently -H, -CH3, -CH2CH3, -CH(CH3)2, -C(CH3)3, -CH2-C6H5, or -CH2-CH(CH3)2; R 41 is -CH3, -CH2CH3, or -C6H5.

[0040] In some embodiments, polymers comprising multiple repeat units of formula (I) are formed from the superacid-catalyzed polyhydroxyalkylation reaction of monomers Ar1', Ar2', and X1'.

[0041] Ar1' is

[0042] [ka] and mixtures thereof.

[0043] Ar2' is

[0044] [ka] and mixtures thereof.

[0045] X1' is

[0046] [ka] or

[0047] [ka]

[0048] [ka] The compound is selected from the group consisting of a mixture of one or more of:

[0049] R1~R 34 are each independently hydrogen, halogen, an alkyl group, an alkenyl group, an alkynyl group, or an aryl group. The alkyl group, the alkenyl group, the alkynyl group, or the aryl group may be substituted with a halogen.

[0050] R 37 ~R 40 are each independently a hydrogen atom, an alkyl group, an alkenyl group, an alkynyl group, or an aryl group. The alkyl group, the alkenyl group, the alkynyl group, or the aryl group may be substituted with a halogen atom.

[0051] R 41 is an alkyl group, an alkenyl group, an alkynyl group, or an aryl group, and the alkyl group, the alkenyl group, the alkynyl group, or the aryl group may be substituted with a halogen.

[0052] A1, A2, and A3 are each independently O, S, or NH; p is 1, 2, 3, or 4; q is 0, 1, 2, or 3; and r, s, and t are independently 0, 1, 2, or 3.

[0053] In some embodiments, Ar1′ is

[0054] [ka] and mixtures thereof; In the formula, R 25 , R 26 , R 27 , and R 28 are each independently -H or -CH3; p is 1 or 2; q is 0 or 1.

[0055] In some embodiments, Ar2' is

[0056] [ka] and mixtures thereof; In the formula, R 29 , R 30 , R 31 , R 32 , R 33 , and R 34 are each independently -CH3 or -CF3, r, s, and t are independently 0 or 1.

[0057] In some embodiments, X1' is

[0058] [ka] where R 37 , R 38 , and R 39 are each independently -H, -CH3, -CH2CH3, -CH(CH3)2, -C(CH3)3, -CH2-C6H5, or -CH2-CH(CH3)2.

[0059] In some embodiments, X1' is

[0060] [ka] where R 37 , R 38 , and R 39 are each independently -H, -CH3, -CH2CH3, -CH(CH3)2, -C(CH3)3, -CH2-C6H5, or -CH2-CH(CH3)2; R 41 is -CH3, -CH2CH3, or -C6H5.

[0061] In some embodiments, X1' is

[0062] [ka] where R 37 , R 38 , R 39 , and R 40 are each independently -H, -CH3, -CH2CH3, -CH(CH3)2, -C(CH3)3, -CH2-C6H5, or -CH2-CH(CH3)2.

[0063] In some embodiments, X1' is

[0064] [ka] where R 37 , R 38 , R 39 , and R 40 are each independently -H, -CH3, -CH2CH3, -CH(CH3)2, -C(CH3)3, -CH2-C6H5, or -CH2-CH(CH3)2; R 41 is -CH3, -CH2CH3, or -C6H5.

[0065] Highly selective and highly CO2 plasticization resistant polymers comprising multiple repeat units of formula (I), such as poly(aryl-biphenol-isatin) polymers, may be synthesized by the superacid-catalyzed polyhydroxyalkylation reaction of monomers Ar1' and Ar2' with X1', for example, the superacid-catalyzed polyhydroxyalkylation reaction of p-terphenyl as Ar1' and 2,2'-dihydroxybiphenyl as Ar2' with isatin as X1'.

[0066] The polyhydroxyalkylation reaction of monomers Ar1' and Ar2' with monomer X1' provides a polymer with a polymer backbone free of ether bonds, resulting in high chemical stability. The incorporation of electron-rich monomer Ar1' into a polymer provides a hydrophobic polymer backbone, while the incorporation of monomer Ar2' with phenolic hydroxyl functionality into a polymer results in the formation of H-bonds on the polymer side chains. The incorporation of monomer X1' into a polymer provides a polymer with isatin-based moieties that increase the polymer's rigidity and free volume, which helps achieve high gas permeability. Therefore, polymer membranes prepared from this type of polymer have high chemical and thermal stability, high mechanical stability, high gas permeability, high selectivity, and high CO2 plasticization resistance for gas separation.

[0067] In some cases, the monomer X1' is a mixture of isatin and non-isatin monomers to allow for the formation of high molecular weight polymers. The molar ratio of Ar1' to Ar2' monomers for the synthesis of polymers containing multiple repeating units of formula (I) can be in the range of 0:1 to 20:1, or in the range of 10:1 to 1:10, or in the range of 5:1 to 1:5. The molar ratio of X1' monomer to Ar1' and Ar2' monomers for the synthesis of polymers containing multiple repeating units of formula (I) can be in the range of 1.2:1 to 1:1.2, or in the range of 1.1:1 to 1:1.1, or in the range of 1.05:1 to 1:1.05.

[0068] The superacid-catalyzed polyhydroxyalkylation reaction can be carried out at 0°C to 50°C, or 10°C to 30°C, or 20°C to 30°C, for 2 hours to 72 hours, or 10 hours to 48 hours, or 12 hours to 24 hours. Suitable superacid catalysts include, but are not limited to, trifluoromethanesulfonic acid (CFSOH (TFSA)), methanesulfonic acid (MSA), fluorosulfuric acid (FSOH), or mixtures thereof. Solvents for the polyhydroxyalkylation reaction are those capable of dissolving one or more of the monomers. Suitable solvents include, but are not limited to, methylene chloride, chloroform, trifluoroacetic acid (TFA), or mixtures thereof.

[0069] High selectivity and high CO2 plasticization resistance polymers have a weight average molecular weight in the range of 10,000 to 1,000,000 daltons, or in the range of 50,000 to 500,000 daltons.

[0070] Another aspect of the present invention is a highly selective and highly CO2 plasticization-resistant polymeric membrane comprising the polymer described above. In some embodiments, the highly selective and highly CO2 plasticization-resistant polymeric membrane is an integral skin asymmetric membrane or a thin film composite (TFC) membrane.

[0071] In some embodiments, the thin film composite membrane comprises a porous substrate membrane coated with a highly selective and highly CO2 plasticization-resistant polymer comprising a plurality of repeating units of formula (I). The porous substrate membrane is prepared from a polymer that may be the same as or different from the highly selective and highly CO2 plasticization-resistant polymer comprising a plurality of repeating units of formula (I).

[0072] In some embodiments, the integral skin asymmetric or TFC membrane may be a flat sheet membrane or a hollow fiber membrane.

[0073] In some embodiments, the highly selective and highly CO2 plasticization resistant polymers comprising multiple repeating units of formula (I) are fabricated into spiral wound, hollow fiber, or plate and frame membrane modules.

[0074] An asymmetric integral skin membrane comprising a highly selective and highly CO2 plasticization-resistant polymer comprising a plurality of repeating units of formula (I) has an asymmetric integral skin membrane structure with a thin selective skin layer on a porous support layer simultaneously formed from the same membrane material by a one-step phase inversion process.

[0075] In some embodiments, an asymmetric flat sheet membrane with an integral skin layer comprising a highly selective and highly CO2 plasticization resistant polymer can be prepared by 1) preparing a membrane casting solution comprising a polymer having formula (I), a solvent that is miscible with water and capable of dissolving the polymer having formula (I), and a non-solvent that is incapable of dissolving the polymer having formula (I); 2) casting a layer of the membrane casting solution onto a support substrate using a membrane caster; and 3) evaporating the solvent and non-solvent from the surface of the coated layer on the support substrate to form a nascent flat sheet membrane having a thin, dense, selective skin layer on its surface. 4) coagulating the coated polymer layer in a coagulation bath to form an integral skinned asymmetric membrane structure comprising a thin non-porous dense layer on a porous support layer coated on a support substrate; and 5) drying the membrane at 50°C to 150°C, or 50°C to 120°C, or 80°C to 120°C. Optionally, 6) a membrane post-treatment step can be added after step 5) to further improve selectivity without altering or damaging the membrane or causing it to lose performance over time. The membrane post-treatment step can involve coating the selective layer surface of the membrane with a thin layer of material such as polysiloxane, fluoropolymer, heat-curable silicone rubber, or UV-curable silicone rubber. The support substrate may be highly porous and include polyolefins such as polypropylene and polyethylene, polyesters, polyamides such as nylon 6 and nylon 6,6, cellulose, polybenzimidazole, polycarbonate, or fluorocarbon polymers such as polytetrafluoroethylene (PTFE) and polyvinylidene fluoride (PVDF). These polymers offer a variety of properties, including low cost, high air permeability, and good chemical, thermal, and mechanical stability. The support substrate can be either a nonwoven or woven matrix and can have either a symmetric or asymmetric porous structure.

[0076] Solvents for preparing the membrane casting solution may include, but are not limited to, N-methyl-2-pyrrolidone (NMP), dimethylacetamide (DMAc), dimethylformamide (DMF), dimethyl sulfoxide (DMSO), dioxane, 1,3-dioxolane, and mixtures thereof. Non-solvents for preparing the membrane casting solution include, but are not limited to, acetone, methanol, ethanol, tetrahydrofuran (THF), toluene, n-octane, n-decane, lactic acid, citric acid, isopropanol, and mixtures thereof. The asymmetric flat-sheet membrane with an integral skin layer may have a thin, non-porous, dense layer less than 100 nm thick on a porous support layer.

[0077] In some embodiments, an asymmetric hollow fiber membrane with an integral skin comprising a highly selective and highly CO2 plasticization-resistant polymer comprising a plurality of repeating units of Formula (I) can be prepared by: 1) preparing a membrane spinning solution comprising a polymer having Formula (I), a solvent that is miscible with water and capable of dissolving the polymer having Formula (I), and a non-solvent that is incapable of dissolving the polymer having Formula (I); 2) co-spinning the spinning solution with a bore fluid from an annular spinneret using a hollow fiber spinner, wherein the bore fluid is pumped into the center of the annulus and the spinning solution is pumped to the outer layer of the annulus; and 3) passing the nascent hollow fiber membrane through the gap between the surface of the spinneret and the surface of a non-solvent coagulation bath to evaporate the solvent and non-solvent for a period of time to form a thin, dense, selective membrane on the surface. 4) immersing the nascent hollow fiber membrane in a non-solvent (e.g., water) coagulation bath at a controlled temperature between 0°C and 50°C to generate a porous non-selective support layer under a thin, dense, selective skin layer by phase inversion, followed by winding the hollow fiber onto a drum, roll, or other suitable device; 5) solvent exchange with an alcohol or a hydrocarbon solvent, such as hexane, or both, at room temperature for a period of time; 6) annealing the wet hollow fiber in a water bath at a constant temperature between 50°C and 100°C for a period of time between 10 minutes and 12 hours; and 7) drying the hollow fiber membrane at a constant temperature between 50°C and 150°C or between 70°C and 100°C. It is noteworthy that the order of the solvent exchange step (5) and the annealing step (6) helps achieve high membrane performance and prevent fires caused by the flammable methanol solvent during the final membrane drying step. Optionally, a membrane post-treatment step can be added after step 7) to further improve selectivity but without altering or damaging the membrane or causing it to lose performance over time. The membrane post-treatment step can involve coating the selective layer surface of the hollow fiber membrane with a thin layer of material such as polysiloxane, fluoropolymer, heat-cured silicone rubber, or UV-cured silicone rubber.Hollow fiber membranes fabricated using this approach contain an ultrathin, defect-free, dense, selective skin layer, less than 100 nm, on a porous, non-selective layer, with both layers fabricated from the same membrane material containing multiple repeat units of formula (I).

[0078] Solvents for preparing spinning solutions for hollow fiber membranes may include, but are not limited to, NMP, DMAc, DMF, DMSO, dioxane, 1,3-dioxolane, and mixtures thereof. Non-solvents for preparing membrane casting solutions include, but are not limited to, acetone, methanol, ethanol, THF, toluene, n-octane, n-decane, lactic acid, citric acid, isopropanol, and mixtures thereof. The integral skin asymmetric hollow fiber membrane may have a thin, non-porous, dense layer less than 100 nm thick on a porous support layer.

[0079] In some embodiments, thin-film composite membranes comprising highly selective and highly CO2 plasticization-resistant polymers comprising a plurality of repeating units of Formula (I) are prepared using a method comprising: 1) dissolving a polymer comprising a plurality of repeating units of Formula (I) in a solvent to form a polymer coating solution; 2) coating a layer of the polymer coating solution onto one surface of a porous support membrane via dip coating, meniscus coating, spin coating, casting, soaking, spraying, painting, or other known conventional solution coating techniques; and 3) drying the coated membrane at 50°C to 150°C, or 50°C to 120°C, or 80°C to 120°C. Optionally, 4) a membrane post-treatment step can be added after step 3) to further improve selectivity without altering or damaging the membrane or causing it to lose performance over time. The membrane post-treatment step can involve coating the selective layer surface of the membrane with a thin layer of a material such as polysiloxane, fluoropolymer, heat-curable silicone rubber, or UV-curable silicone rubber. Solvents for preparing thin-film composite membranes may include, but are not limited to, NMP, DMAc, DMF, DMSO, dioxane, 1,3-dioxolane, chloroform, dichloromethane, and mixtures thereof. The porous support membrane should have good thermal stability (stable up to at least 120°C), high chemical stability in organic solvents, high mechanical strength (no dimensional change under system operating conditions), and other factors determined by the operating conditions of gas or liquid separation. The porous support membrane must be compatible with the chemistry of the polymer coating solution and meet the mechanical requirements of the membrane assembly operation.

[0080] Suitable polymers for preparing porous support membranes can be selected from, but are not limited to, polyolefins such as polyethylene and polypropylene, polyamides such as nylon 6 and nylon 6,6, polyesters, cellulose acetate, polybenzimidazole, fluorocarbon polymers such as PTFE and PVDF, polycarbonates, cellulose, or combinations thereof. These polymers offer a variety of properties, such as low cost, high chemical and thermal stability, good mechanical stability, and ease of processing for membrane fabrication.

[0081] Another aspect of the present invention is the use of highly selective and highly CO2 plasticization-resistant polymeric membranes comprising a highly selective and highly CO2 plasticization-resistant polymer comprising a plurality of repeating units of formula (I) for a wide range of gas separations, such as acid gas removal from natural gas or biogas, H2 recovery, He recovery, and air separation.

[0082] The present invention provides a process for separating at least one gas from a mixture of gases using the novel highly selective and highly CO2 plasticization-resistant polymeric membrane described in this invention, the process comprising: (a) providing a highly selective and highly CO2 plasticization-resistant polymeric membrane that is permeable to at least one gas; (b) contacting the mixture on one side of the membrane to cause at least one gas to permeate through the membrane; and (c) removing from the other side of the membrane a permeate gas composition comprising a portion of the at least one gas that permeated the membrane.

[0083] Highly selective and highly CO2 plasticization-resistant polymeric membranes are particularly useful in the purification, separation, or adsorption of specific species in the gas phase. Highly selective and highly CO2 plasticization-resistant polymeric membranes are particularly useful in gas separation processes in the air purification, renewable energy, petrochemical, refinery, and natural gas industries. Examples of such separations include the separation of volatile organic compounds (such as toluene, xylene, and acetone) from atmospheric gases such as nitrogen or oxygen, and nitrogen recovery from air. Further examples of such separations are the separation of CO2 and / or H2S from natural gas or biogas, the separation of H2 from N2, CH4, and Ar in ammonia purge gas streams, H2 recovery in refineries, He recovery from natural gas, olefin / paraffin separation such as propylene / propane separation, and iso / normal paraffin separation. Any given pair or group of gases with different molecular sizes, such as nitrogen and oxygen, carbon dioxide and methane, hydrogen and methane or carbon monoxide, helium and methane, can be separated using highly selective and highly CO2 plasticization-resistant polymeric membranes. Three or more gases can be removed from a third gas. For example, some of the gas components that can be selectively removed from a feed natural gas using the membranes described herein include carbon dioxide, oxygen, nitrogen, water vapor, hydrogen sulfide, helium, and other trace gases. Some gas components that can be selectively retained include hydrocarbon gases. When the permeable component is an acid component selected from the group consisting of carbon dioxide, hydrogen sulfide, and mixtures thereof, and is removed from a hydrocarbon mixture such as natural gas, a single module, or at least two parallel services, or a series of modules, may be utilized to remove the acid component. For example, when a single module is utilized, the pressure of the feed gas may vary from 275 kPa to 2.6 MPa (25 to 4000 psi). The differential pressure across the membrane can be as low as 70 kPa or as high as 14.5 MPa (10 psi or 2100 psi), depending on many factors, such as the specific membrane used, the flow rate of the inlet stream, and the availability of a compressor to compress the permeate stream if such compression is desired. A pressure difference greater than 14.5 MPa (2100 psi) may cause the membrane to burst.The operating temperature of the process may vary depending on the temperature of the feed stream and ambient temperature conditions. Preferably, the effective operating temperature of the membranes of the present invention ranges from -50° to -150° C. More preferably, the effective operating temperature of the highly selective and highly CO2 plasticization-resistant polymeric membranes ranges from -50° to 100° C.

[0084] Highly selective and highly CO2 plasticization-resistant polymeric membranes are also particularly useful in gas / vapor separation processes in the chemical, petrochemical, pharmaceutical, and related industries, for example, in off-gas treatment for the recovery of volatile organic compounds to meet clean air regulations, or in process streams in manufacturing plants to remove organic vapors from gas streams so that valuable compounds (e.g., vinyl chloride monomer or propylene) can be recovered. Further examples of gas / vapor separation processes in which highly selective and highly CO2 plasticization-resistant polymeric membranes may be used are hydrocarbon vapor separation from hydrogen in oil and gas refineries for hydrocarbon dew point indication of natural gas (i.e., to lower the hydrocarbon dew point below the lowest possible export pipeline temperature so that liquid hydrocarbons do not separate in the pipeline), for control of methane number in fuel gas for gas engines and gas turbines, and for gasoline recovery. Highly selective and highly CO2 plasticization-resistant polymeric membranes may incorporate species that strongly adsorb certain gases (e.g., cobalt porphyrin or phthalocyanine for O2, or silver(I) for ethane) to facilitate their transport across the membrane.

[0085] The highly selective and highly CO2 plasticization-resistant polymeric membranes described herein may also be used in the separation of liquid mixtures by pervaporation, for example, in the removal of organic compounds (e.g., alcohols, phenols, chlorinated hydrocarbons, pyridine, ketones) from water, such as aqueous effluents or process fluids. Membranes that are ethanol-selective are used to increase the ethanol concentration in relatively dilute ethanol solutions (e.g., 5-10% ethanol) obtained by fermentation processes. Another example of liquid-phase separation using highly selective and highly CO2 plasticization-resistant polymeric membranes is the deep desulfurization of gasoline and diesel fuels by pervaporation membrane processes. Highly selective and highly CO2 plasticization-resistant polymeric membranes that are selective for sulfur-containing molecules are used to selectively remove sulfur-containing molecules from fluid catalytic cracking (FCC) and other naphtha hydrocarbon streams. Additional liquid-phase examples include the separation of one organic component from another, for example, separating isomers of organic compounds. Mixtures of organic compounds that may be separated using highly selective and highly CO2 plasticization-resistant polymeric membranes include ethyl acetate-ethanol, diethyl ether-ethanol, acetic acid-ethanol, benzene-ethanol, chloroform-ethanol, chloroform-methanol, acetone-isopropyl ether, allyl alcohol-allyl ether, allyl alcohol-cyclohexane, butanol-butyl acetate, butanol-1-butyl ether, ethanol-ethyl butyl ether, propyl acetate-propanol, isopropyl ether-isopropanol, methanol-ethanol-isopropanol, and ethyl acetate-ethanol-acetic acid.

[0086] Yet another aspect of the present invention is the use of highly selective and highly CO2 plasticization resistant polymeric membrane materials comprising a plurality of repeat units of formula (I) for the preparation of derivative functional polymers that may be used in a wide variety of applications, including, but not limited to, fuel cells, electrolyzers, flow batteries, electrodialysis devices, waste metal recovery systems, electrocatalytic hydrogen production systems, desalination devices, water purifiers, wastewater treatment systems, ion exchangers, or CO2 separation devices. [Example]

[0087] The following examples are provided to illustrate, but not to limit, one or more preferred embodiments of the invention. Many variations can be made to the following examples that remain within the scope of the invention.

[0088] Example 1: Synthesis of poly(p-terphenyl-2,2'-biphenol-1-1-isatin) polymer (abbreviated as poly(TP-DHB-1-1-isatin)). Poly(p-terphenyl-2,2'-biphenol-1-1-isatin) polymer (abbreviated as poly(TP-DHB-1-1-isatin)) was synthesized by the superacid-catalyzed polyhydroxyalkylation reaction of the monomers 2,2-dihydroxybiphenyl and p-terphenyl with isatin, as shown in Figure 1. The molar ratio of 2,2-dihydroxybiphenyl:p-terphenyl:isatin was 1:1:2. p-Terphenyl (5.76 g, 25 mmol) and 2,2'-biphenol (4.67 g, 25 mmol) were placed in a 500 mL three-neck flask equipped with an overhead mechanical stirrer. Anhydrous methylene chloride (50 mL) was added flash and stirred for 5 minutes to form a suspension. The flask was then immersed in an ice bath to keep the suspension cool. A mixture of trifluoromethanesulfonic acid (50 mL), trifluoroacetic acid (25 mL), and isatin (7.36 g, 50 mmol) was added dropwise to the flask. The reaction was then continued for 16 hours. The resulting viscous solution was slowly poured into a mixture of water and methanol with stirring. The solid was crushed into powder using a blender, filtered, washed with water, and soaked in 0.5 M K2CO3 overnight to completely remove the acid. The polymer was filtered, washed thoroughly with methanol, and then dried under vacuum at 80 °C. The yield of the polymer poly(TP-DHB-1-1-isatin) was 97%.

[0089] Example 2: Synthesis of poly(p-terphenyl-2,2'-biphenol-1-3-isatin) polymer (abbreviated as poly(TP-DHB-1-3-isatin)) Poly(p-terphenyl-2,2'-biphenol-1-3-isatin) polymer (abbreviated as poly(TP-DHB-1-3-isatin)) was synthesized using the same synthesis procedure as that for poly(TP-DHB-1-1-isatin) in Example 1, except that the molar ratio of 2,2-dihydroxybiphenyl to p-terphenyl was 1:3 instead of 1:1. The yield of poly(TP-DHB-1-3-isatin) was 96%.

[0090] Example 3: Synthesis of poly(p-terphenyl-2,2'-biphenyl-1-3-isatin-2,2,2-trifluoroacetophenone-4-1) polymer (abbreviated as poly(TP-DHB-1-3-isatin-TFAP-4-1)) Poly(p-terphenyl-2,2'-biphenol-1-3-isatin-2,2,2-trifluoroacetophenone-4-1) polymer (abbreviated as poly(TP-DHB-1-3-isatin-TFAP-4-1)) was synthesized by the superacid-catalyzed polyhydroxyalkylation reaction of the monomers 2,2-dihydroxybiphenyl and p-terphenyl with isatin and 2,2,2-trifluoroacetophenone, as shown in Figure 2. The molar ratio of 2,2-dihydroxybiphenyl:p-terphenyl:isatin:2,2,2-trifluoroacetophenone was 1:1:1.6:0.4. p-Terphenyl (5.76 g, 25 mmol) and 2,2'-biphenol (4.67 g, 25 mmol) were placed in a 500 mL three-neck flask equipped with an overhead mechanical stirrer. Anhydrous methylene chloride (50 mL) was added to the flash and stirred for 5 minutes to form a suspension. The flask was then immersed in an ice bath to keep the suspension cool. A mixture of trifluoromethanesulfonic acid (50 mL), trifluoroacetic acid (25 mL), isatin (5.89 g, 40 mmol), and 2,2,2-trifluoroacetophenone (1.74 g, 10 mmol) was added dropwise to the flask. The reaction was then continued for 14 hours. The resulting viscous solution was slowly poured into a mixture of water and methanol with stirring. The solid was crushed into powder using a blender, filtered, washed with water, and soaked in 0.5 M K2CO3 overnight to completely remove the acid. The polymer was filtered, washed thoroughly with methanol, and then dried under vacuum at 80 °C. The yield of the polymer poly(TP-DHB-1-3-isatin-TFAP-4-1) was 96%.

[0091] Example 4: Preparation of poly(TP-DHB-1-1-isatin) dense film membrane Poly(TP-DHB-1-1-isatin) dense film membranes were prepared by dissolving 5.0 g of poly(TP-DHB-1-1-isatin) polymer synthesized in Example 1 in 20.0 g of DMSO solvent, casting the solution onto a clean glass plate, and drying at 60° C. for 12 hours. The membranes were peeled off from the glass plate and further dried in a vacuum oven at 120° C. for 48 hours.

[0092] Example 5: Preparation of poly(TP-DHB-1-3-isatin) dense film membrane Poly(TP-DHB-1-3-isatin) dense film membranes were prepared using the same procedure as used for the poly(TP-DHB-1-1-isatin) dense film membrane described in Example 4.

[0093] Comparative Example 1: Preparation of cellulose acetate (CA) / cellulose triacetate (CTA) blend dense film membrane (abbreviated as CA / CTA) 0.5 g of cellulose acetate (CA) polymer and 0.5 g of cellulose triacetate (CTA) polymer were dissolved in 20.0 g of NMP solvent. The mixture was stirred at room temperature for 6 hours to form a homogeneous solution. The solution was cast onto the surface of a clean glass plate and dried at 60°C for 12 hours. The film was peeled off from the glass plate and further dried in a vacuum oven at 120°C for 48 hours.

[0094] Comparative Example 2: Preparation of polyimide dense film (abbreviated as PI) 5.0 g of polyimide polymer (Matrimid® available from Huntsman Corporation) was dissolved in 20.0 g of NMP solvent. The mixture was stirred at room temperature for 3 hours to form a homogeneous solution. The solution was cast onto the surface of a clean glass plate and dried at 60°C for 12 hours. The film was peeled off from the glass plate and further dried in a vacuum oven at 120°C for 48 hours.

[0095] Example 6: Evaluation of gas permeation properties of poly(TP-DHB-1-1-isatin) and poly(TP-DHB-1-3-isatin) dense film membranes The gas permeation properties of poly(TP-DHB-1-1-isatin) (Example 4), poly(TP-DHB-1-3-isatin) (Example 5), CA / CTA (Comparative Example 1), and PI (Comparative Example 2) dense film membranes for CO / CH and H / CH separation were evaluated using a fixed-volume gas permeation test unit at 50°C under 791 kPa (100 psig) pure single-feed gas pressure. The results are shown in Table 1.

[0096] It can be seen from Table 1 that poly(TP-DHB-1-1-isatin) and poly(TP-DHB-1-3-isatin) membranes have similar CO permeability, higher H permeability, higher CO / CH selectivity, and higher H / CH selectivity than CA / CTA membranes for CO / CH and H / CH separations. Poly(TP-DHB-1-1-isatin) and poly(TP-DHB-1-3-isatin) membranes also have higher CO / CH selectivity and higher H / CH selectivity than PI membranes for CO / CH and H / CH separations. Furthermore, poly(TP-DHB-1-1-isatin) and poly(TP-DHB-1-3-isatin) dense film membranes exhibited significantly higher CO plasticization resistance than PI and CA / CTA membranes for natural gas upgrading and biogas purification applications.

[0097] To study the CO2 plasticization resistance of poly(TP-DHB-1-1-isatin), CA / CTA, and PI dense film membranes, the membranes were conditioned with CO2 at different pressures. Figure 3 shows the change in CO2 relative permeability with increasing applied CO2 pressure at 50 °C for all membranes. The CA / CTA membrane showed a 44% increase in CO2 permeability under an applied CO2 pressure of 500 psig compared to the permeability at an applied CO2 pressure of 100 psig. When the applied CO2 pressure was increased to 800 psig, the CA / CTA membrane showed a 149% increase in CO2 permeability. Similarly, the PI membrane showed a 71% increase in CO2 permeability under an applied CO2 pressure of 500 psig compared to the permeability at an applied CO2 pressure of 100 psig. When the applied CO2 pressure was increased to 800 psig, the PI membrane showed a 209% increase in CO2 permeability. The significant increase in CO permeability when the applied CO pressure exceeded 300 psig was attributed to CO plasticization (swelling) of the CA / CTA blend polymer and PI polymer, respectively. However, CO plasticization was not observed for the poly(TP-DHB-1-1-isatin) membrane up to an applied CO pressure of 675 psig. The significant enhancement in CO plasticization resistance for the poly(TP-DHB-1-1-isatin) membrane compared with the CA / CTA and PI membranes is primarily due to the rigid polymer chain structure and the formation of H-bonds between the polymer chains. These results indicate that the poly(TP-DHB-1-1-isatin) membrane is a good candidate membrane for natural gas upgrading and biogas purification applications.

[0098] [Table 1] a P CO2 , P H2 , and P CH4 was tested at 50°C and 690 kPa (100 psig). 1 barrer = 10 -10 cm 3 (STP).cm / cm 2 .sec.cmHg.

[0099] Example 7: Preparation of poly(TP-DHB-1-3-isatin-TFAP-4-1) hollow fiber membrane A hollow fiber spin dope containing 26.0 wt. % poly(TP-DHB-1-3-isatin-TFAP-4-1) polymer synthesized in Example 3 was prepared. The spin dope was extruded through a spinneret at a spinning temperature of 50°C at a flow rate of 3.5 mL / min. A bore fluid containing 10 wt. % water in NMP was injected into the fiber bore at a flow rate of 0.7 mL / min simultaneously with the extrusion of the spin dope. The nascent fiber passed through a 5 cm air gap length at room temperature (<40% humidity) and was immersed in a water coagulant bath at 10°C and wound at a speed of 37.7 m / min. The water-wet fibers were cut to length and assembled together into bundles. The water-wet hollow fiber bundle was solvent-exchanged three times with methanol for 30 min each, followed by annealing in a water bath at 85°C for 30 min. The annealed water-wet hollow fiber bundle was dried in an oven at 85°C for 1.5 hours to form a poly(TP-DHB-1-3-isatin-TFAP-4-1) polymer hollow fiber membrane.

[0100] Example 8: Preparation of poly(TP-DHB-1-1-isatin) asymmetric flat sheet membrane An asymmetric flat-sheet membrane casting dope containing 19.0 wt. % poly(TP-DHB-1-1-isatin) polymer synthesized in Example 1 was prepared. The casting dope was cast onto a more porous, non-selective, symmetrically woven nylon 6,6 fabric backing at room temperature at a casting speed of 6 fpm. The cast membrane was evaporated for 13 seconds to form a nascent asymmetric, integrated-skinned flat-sheet membrane with a thin dense, selective skin layer on the surface. The membrane was immersed in a cold water coagulation tank to generate a porous, non-selective asymmetric layer beneath the thin dense, selective skin layer by phase inversion. The wet membrane was then immersed in a hot water tank to remove traces of organic solvent in the membrane. Finally, the wet membrane was wound onto a core roll for further drying. The wet membrane was dried at 75°C. The thin dense, selective skin layer of the dried membrane was then coated with a thin, non-porous layer of epoxy silicone rubber. The epoxy silicone rubber coating layer was crosslinked by UV irradiation using a UV lamp for 1.75 minutes to produce a poly(TP-DHB-1-1-isatin) asymmetric flat sheet membrane with an integral skin layer.

[0101] Specific Embodiments While the following will be described in conjunction with specific embodiments, it will be understood that this description is illustrative, but not intended to limit the scope of the foregoing description and appended claims.

[0102] A first embodiment of the present invention is a compound of formula (I)

[0103] [ka] is a polymer comprising a plurality of repeat units of In the formula, Ar1 is

[0104] [ka] and mixtures thereof, and Ar2 is selected from the group consisting of:

[0105] [ka] and mixtures thereof, and X1 is selected from the group consisting of:

[0106] [ka] or

[0107] [ka]

[0108] [ka] and a mixture of one or more of: In the formula, R1~R 36 are each independently hydrogen, halogen, an alkyl group, an alkenyl group, an alkynyl group, or an aryl group, and the alkyl group, the alkenyl group, the alkynyl group, or the aryl group may be substituted with a halogen; R 37 ~R 40 are each independently a hydrogen atom, an alkyl group, an alkenyl group, an alkynyl group, or an aryl group, and the alkyl group, the alkenyl group, the alkynyl group, or the aryl group may be substituted with a halogen atom; R 41 is an alkyl group, an alkenyl group, an alkynyl group, or an aryl group, the alkyl group, the alkenyl group, the alkynyl group, or the aryl group being optionally substituted with a halogen, the halogen being F, Cl, Br, or I; A1, A2, and A3 are each independently O, S, or NH; m is an integer from 5 to 5000; n is an integer from 0 to 5000, the molar ratio of n / m is 0:1 to 20:1; p is 1, 2, 3, or 4; q is 0, 1, 2, or 3; and r, s, t, and o are independently 0, 1, 2, or 3. Embodiments of the invention include one, any, or all of the preceding embodiments of this paragraph through the first embodiment of this paragraph, wherein Ar1 is

[0109] [ka] and mixtures thereof, wherein R 25 , R 26 , R 27 , and R 28 are each independently -H or -CH3, p is 1 or 2, and q is 0 or 1. Embodiments of the invention are one, any, or all of the preceding embodiments of this paragraph through the first embodiment of this paragraph, wherein Ar2 is

[0110] [ka] and mixtures thereof, wherein R 29 , R 30 , R 31 , R 32 , R 33 , R 34 , R 35 , and R 36 are each independently -CH3 or -CF3, and r, s, t, and o are each independently 0 or 1. Embodiments of the invention are one, any, or all of the preceding embodiments of this paragraph through the first embodiment of this paragraph, wherein X1 is

[0111] [ka] where R 37 , R 38 , and R 39 are each independently -H, -CH3, -CH2CH3, -CH(CH3)2, -C(CH3)3, -CH2-C6H5, or -CH2-CH(CH3)2. Embodiments of the invention are one, any, or all of the preceding embodiments of this paragraph through the first embodiment of this paragraph, wherein X1 is

[0112] [ka] where R 37 , R 38 , and R 39 are each independently -H, -CH3, -CH2CH3, -CH(CH3)2, -C(CH3)3, -CH2-C6H5, or -CH2-CH(CH3)2, and R 41 is -CH3, -CH2CH3, or -C6H5. Embodiments of the invention are one, any, or all of the preceding embodiments of this paragraph through the first embodiment of this paragraph, wherein X1 is

[0113] [ka] where R 37 , R 38 , R 39 , and R 40 are each independently -H, -CH3, -CH2CH3, -CH(CH3)2, -C(CH3)3, -CH2-C6H5, or -CH2-CH(CH3)2. Embodiments of the invention are one, any, or all of the preceding embodiments of this paragraph through the first embodiment of this paragraph, wherein X1 is

[0114] [ka] where R 37 , R 38 , R 39 , and R 40 are each independently -H, -CH3, -CH2CH3, -CH(CH3)2, -C(CH3)3, -CH2-C6H5, or -CH2-CH(CH3)2, and R 41is -CH3, -CH2CH3, or -C6H5. An embodiment of the invention is one, any, or all of the preceding embodiments of this paragraph through the first embodiment of this paragraph, wherein the polymer is synthesized by reacting monomers Ar1', Ar2', and X1' in a superacid-catalyzed polyhydroxyalkylation reaction, wherein Ar1' is

[0115] [ka] and mixtures thereof, and Ar2' is selected from the group consisting of:

[0116] [ka] and mixtures thereof, and X1' is selected from the group consisting of:

[0117] [ka] or

[0118] [ka]

[0119] [ka] and a mixture of one or more of: In the formula, R1~R 34 are each independently hydrogen, halogen, an alkyl group, an alkenyl group, an alkynyl group, or an aryl group, and the alkyl group, the alkenyl group, the alkynyl group, or the aryl group may be substituted with a halogen; R 37 ~R 40are each independently a hydrogen atom, an alkyl group, an alkenyl group, an alkynyl group, or an aryl group, and the alkyl group, the alkenyl group, the alkynyl group, or the aryl group may be substituted with a halogen atom; R 41 is an alkyl group, an alkenyl group, an alkynyl group, or an aryl group, wherein the alkyl group, alkenyl group, alkynyl group, or aryl group is optionally substituted with halogen; A1, A2, and A3 are each independently O, S, or NH; p is 1, 2, 3, or 4; q is 0, 1, 2, or 3; and r, s, and t are independently 0, 1, 2, or 3. Embodiments of the invention are one, any, or all of the preceding embodiments of this paragraph through the first embodiment of this paragraph, wherein Ar1′ is

[0120] [ka] and mixtures thereof, wherein R 25 , R 26 , R 27 , and R 28 are each independently -H or -CH3, p is 1 or 2, and q is 0 or 1. Embodiments of the invention are one, any, or all of the preceding embodiments of this paragraph through the first embodiment of this paragraph, wherein Ar2' is:

[0121] [ka] and mixtures thereof, wherein R 29 , R 30 , R 31 , R 32 , R 33 , and R 34 are each independently —CH3 or —CF3, and r, s, and t are independently 0 or 1. Embodiments of the invention are one, any, or all of the preceding embodiments of this paragraph through the first embodiment of this paragraph, wherein X1′ is

[0122] [ka] where R 37 , R 38 , and R 39 are each independently -H, -CH3, -CH2CH3, -CH(CH3)2, -C(CH3)3, -CH2-C6H5, or -CH2-CH(CH3)2. Embodiments of the invention are one, any, or all of the preceding embodiments of this paragraph through the first embodiment of this paragraph, wherein X1' is

[0123] [ka] where R 37 , R 38 , and R 39 are each independently -H, -CH3, -CH2CH3, -CH(CH3)2, -C(CH3)3, -CH2-C6H5, or -CH2-CH(CH3)2, and R 41 is -CH3, -CH2CH3, or -C6H5. Embodiments of the invention are one, any, or all of the preceding embodiments of this paragraph through the first embodiment of this paragraph, wherein X1' is

[0124] [ka] where R 37 , R 38 , R 39 , and R 40 are each independently -H, -CH3, -CH2CH3, -CH(CH3)2, -C(CH3)3, -CH2-C6H5, or -CH2-CH(CH3)2. Embodiments of the invention are one, any, or all of the preceding embodiments of this paragraph through the first embodiment of this paragraph, wherein X1' is

[0125] [ka] where R 37 , R 38 , R 39 , and R 40 are each independently -H, -CH3, -CH2CH3, -CH(CH3)2, -C(CH3)3, -CH2-C6H5, or -CH2-CH(CH3)2, and R 41 is -CH3, -CH2CH3, or -C6H5.

[0126] A second embodiment of the invention is a membrane made from the polymer of the first embodiment.

[0127] A third embodiment of the invention is a process for separating at least one gas from a mixture of gases, the process comprising: (a) providing a membrane made from the polymer of the first embodiment; (b) contacting the mixture of gases with one side of the membrane to allow at least one gas to permeate through the membrane; and (c) removing from the other side of the membrane a permeate gas composition comprising a portion of the at least one gas that permeated through the membrane. An embodiment of the invention is one, any, or all of the preceding embodiments through the third embodiment of this paragraph, wherein the mixture of gases comprises hydrogen sulfide and carbon dioxide in natural gas. An embodiment of the invention is one, any, or all of the preceding embodiments through the third embodiment of this paragraph, wherein the mixture of gases comprises hydrogen sulfide and carbon dioxide in biogas. An embodiment of the invention is one, any, or all of the preceding embodiments through the third embodiment of this paragraph, wherein the mixture of gases comprises hydrogen in a mixture of nitrogen and methane. An embodiment of the invention is one, any, or all of the preceding embodiment of this paragraph through the third embodiment of this paragraph, wherein the mixture of gases includes carbon dioxide in the flue gas.

[0128] Without further elaboration, it is believed that one skilled in the art can, using the preceding description, readily ascertain the essential characteristics of the present invention and make various changes and modifications to the present invention to adapt it to various uses and conditions, all without departing from the spirit and scope of the present invention. The preceding preferred specific embodiments are, therefore, to be construed as merely illustrative, and not limitative of the remainder of the disclosure in any way, and are intended to cover various modifications and equivalent arrangements included within the scope of the appended claims.

[0129] Above, all temperatures are set forth in degrees Celsius and all parts and percentages are by weight unless otherwise stated.

Claims

1. A polymer comprising a plurality of repeat units of formula (I): 【Chemistry 1】 In the formula, Ar １ but, 【Chemistry 2】 and mixtures thereof; Ar ２ but, 【Transformation 3】 and mixtures thereof; X １ but, 【Chemistry 4】 is a mixture of In the formula, R ２５ and R ２６ are each independently hydrogen, halogen, an alkyl group, an alkenyl group, an alkynyl group, or an aryl group, and the alkyl group, the alkenyl group, the alkynyl group, or the aryl group is optionally substituted with halogen; R ３７ ~R ４０ are each independently a hydrogen atom, an alkyl group, an alkenyl group, an alkynyl group, or an aryl group, and the alkyl group, the alkenyl group, the alkynyl group, or the aryl group is optionally substituted with a halogen atom; R ４１ is an alkyl group, an alkenyl group, an alkynyl group, or an aryl group, and the alkyl group, the alkenyl group, the alkynyl group, or the aryl group is optionally substituted with a halogen; the halogen is F, Cl, Br, or I; A １ , A ２ , and A ３ are each independently O, S, or NH; m is an integer from 5 to 5000; n is an integer from 0 to 5000, the molar ratio of n / m is 0:1 to 20:1; p is 1, 2, 3, or 4; polymer.

2. Ar １ but, 【Transformation 5】 and mixtures thereof; In the formula, R ２５ and R ２６ are each independently —H or —CH ３ and 2. The polymer of claim 1, wherein p is 1 or 2.

3. Ar ２ but, 【Transformation 6】 10. The polymer of claim 1, wherein the polymer is selected from the group consisting of:

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