Polybenzimidazole as well as preparation method and application thereof

Abstract

The invention provides a novel polybenzimidazole polymer which shows excellent gas adsorption separation property and also has force-induced discoloration property at the same time. The polybenzimidazole polymer can be used for adsorption separation of gas containing carbon dioxide.

Description

Technical Field

[0001] The present invention relates to the field of polymer materials, and more particularly to polybenzimidazole containing tetraphenylethylene groups, a method for separating gases by adsorption using the polybenzimidazole, and use of the polybenzimidazole for gas adsorption separation. Background Art

[0002] Polybenzimidazole (PBI) refers to a class of heterocyclic polymers containing imidazole rings in the repeating units, which have excellent thermal stability, mechanical stability and chemical stability.

[0003] Polymers are often processed into membrane products such as nanofiltration membranes, hollow fiber membranes, etc. for gas separation and purification due to their excellent processing properties. Although the separation performance is excellent, polymer membrane products usually do not have an adsorption effect. The present invention provides a novel polybenzimidazole polymer, which exhibits a good adsorption effect on gases and exhibits different adsorption selectivities for different gases. Summary of the invention

[0004] The purpose of the present invention is to provide a novel polybenzimidazole polymer having gas adsorption and separation properties. In addition, the polybenzimidazole polymer of the present application has mechanochromic properties.

[0005] The first aspect of the present invention provides a polybenzimidazole, wherein the polybenzimidazole comprises a structural unit A, wherein the structural unit A has a structure shown in formula (1);

[0006]

[0007] Among them, X 1 The X group is a connecting group provided by an aromatic compound containing 1 to 10 benzene rings; and the Y group is a connecting group based on tetraphenylethylene; wherein, 1 The group and the Y group are independently present or absent and are selected from hydroxyl, amino, cyano, halogen, C 1 -C 4 Alkyl, C 1 -C 4 At least one substituent in the haloalkyl group.

[0008] In some embodiments, the polybenzimidazole contains structural unit A and structural unit C, contains structural unit A and structural unit D, or contains structural unit A, structural unit B, structural unit C and structural unit D;

[0009] The structural unit A has a structure shown in formula (1), the structural unit B has a structure shown in formula (2), the structural unit C has a structure shown in formula (1-1), and the structural unit D has a structure shown in formula (2-2):

[0010]

[0011] Among them, X 1 and X 2 The groups are each independently a linking group provided by an aromatic compound containing 1 to 10 benzene rings; the Y group is a linking group based on tetraphenylethylene; and the Z group is an aromatic hydrocarbon containing 1 to 10 benzene rings, a heteroaromatic hydrocarbon containing 1 to 10 heterocyclic rings, an aromatic hydrocarbon containing 1 to 3 heterocyclic rings and 1 to 8 benzene rings, a C 4 -C 10 Cycloalkanes, C 1 -C 8 Alkanes, C 2 -C 8 The connecting group is provided by at least one compound in olefin; wherein X 1 , X 2 , Y and Z groups are independently present or absent and are selected from hydroxyl, amino, cyano, halogen, C 1 -C 4 Alkyl, C 1 -C 4 At least one substituent in the haloalkyl group.

[0012] In some embodiments, the polybenzimidazole contains a structural unit A and an optional structural unit B, wherein the structural unit A has a structure shown in formula (1) and the structural unit B has a structure shown in formula (2);

[0013]

[0014] Among them, X 1 and X 2 The groups are each independently a linking group provided by an aromatic compound containing 1 to 10 benzene rings; the Y group is a linking group based on tetraphenylethylene; and the Z group is an aromatic hydrocarbon containing 1 to 10 benzene rings, a heteroaromatic hydrocarbon containing 1 to 10 heterocyclic rings, an aromatic hydrocarbon containing 1 to 3 heterocyclic rings and 1 to 8 benzene rings, a C 4 -C 10 Cycloalkanes, C 1 -C 8 Alkanes, C 2 -C 8 The connecting group is provided by at least one compound in the olefin, and when the structural unit B exists, Z and Y are different; wherein X 1 , X 2 , Y group and Z group are independently present or absent selected from hydroxyl, amino, cyano, halogen, C 1 -C 4 Alkyl, C 1 -C 4 At least one substituent in the haloalkyl group.

[0015] The present invention also provides a method for preparing the polybenzimidazole of the present invention, which comprises reacting at least one compound having a structure represented by formula (6) with HOOC-Y-COOH and optionally HOOC-Z-COOH;

[0016]

[0017] Wherein, the X group in formula (6) is the same as X defined in the first aspect. 1 and / or X 2 The Y and Z groups in HOOC-Y-COOH and optionally HOOC-Z-COOH are the same as the Y and Z groups defined in the first aspect.

[0018] The present invention also provides a method for separating CO by adsorption. 2 A method for removing gases, wherein the polybenzimidazole according to the invention is used as adsorbent.

[0019] The present invention also provides the use of the polybenzimidazole of the present invention as an adsorbent for gas adsorption separation. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 The graphs are hydrogen NMR spectra of the polymer of Example 1 (PBI-1) and the polymer of Example 2 (PBI-2).

[0021] Figure 2 It is the free volume probability distribution function diagram of PBI-4.

[0022] Figure 3 It is the fluorescence spectrum of PBI-2 before and after grinding.

[0023] Figure 4 The figures are a non-inventive polybenzimidazole polymer (left) and a polymer of Example 4 (PBI-4, right). DETAILED DESCRIPTION

[0024] The first aspect of the present invention provides a polybenzimidazole, wherein the polybenzimidazole contains a structural unit A, and the structural unit A has a structure shown in formula (1);

[0025]

[0026] Among them, X 1 The X group is a connecting group provided by an aromatic compound containing 1 to 10 benzene rings; and the Y group is a connecting group based on tetraphenylethylene; wherein, 1 The group and the Y group are independently present or absent and are selected from hydroxyl, amino, cyano, halogen, C 1 -C 4 Alkyl, C1 -C 4 In some embodiments, the polybenzimidazole consists of structural unit A.

[0027] In some embodiments, the polybenzimidazole contains structural unit A and structural unit C, contains structural unit A and structural unit D, or contains structural unit A, structural unit B, structural unit C and structural unit D;

[0028] The structural unit A has a structure shown in formula (1), the structural unit B has a structure shown in formula (2), the structural unit C has a structure shown in formula (1-1), and the structural unit D has a structure shown in formula (2-2):

[0029]

[0030] Among them, X 1 and X 2 The groups are each independently a linking group provided by an aromatic compound containing 1 to 10 benzene rings; the Y group is a linking group based on tetraphenylethylene; and the Z group is an aromatic hydrocarbon containing 1 to 10 benzene rings, a heteroaromatic hydrocarbon containing 1 to 10 heterocyclic rings, an aromatic hydrocarbon containing 1 to 3 heterocyclic rings and 1 to 8 benzene rings, a C 4 -C 10 Cycloalkanes, C 1 -C 8 Alkanes, C 2 -C 8 The connecting group is provided by at least one compound in olefin; wherein X 1 , X 2 , Y and Z groups are independently present or absent and are selected from hydroxyl, amino, cyano, halogen, C 1 -C 4 Alkyl, C 1 -C 4 At least one substituent in the haloalkyl. In some embodiments, the polybenzimidazole consists of structural units A and structural units C. In some embodiments, the polybenzimidazole consists of structural units A and structural units D. In some embodiments, the polybenzimidazole consists of structural units A, structural units B, structural units C and structural units D.

[0031] In some embodiments, the polybenzimidazole contains a structural unit A and an optional structural unit B, wherein the structural unit A has a structure shown in formula (1) and the structural unit B has a structure shown in formula (2);

[0032]

[0033] Among them, X1 and X 2 The groups are each independently a linking group provided by an aromatic compound containing 1 to 10 benzene rings; the Y group is a linking group based on tetraphenylethylene; the Z group is an aromatic hydrocarbon containing 1 to 10 benzene rings, a heteroaromatic hydrocarbon containing 1 to 10 heterocyclic rings, an aromatic hydrocarbon containing 1 to 3 heterocyclic rings and 1 to 8 benzene rings, or a C 4 -C 10 Cycloalkanes, C 1 -C 8 Alkanes and C 2 -C 8 At least one linking group provided by the olefin, and when the structural unit B exists, Z and Y are different; wherein X 1 , X 2 , Y group and Z group are each independently present or absent and are selected from hydroxyl, amino, cyano, halogen, C 1 -C 4 Alkyl and C 1 -C 4 At least one substituent in the haloalkyl group.

[0034] In the present invention, those skilled in the art will know that X 1 and X 2 The connection mode of the groups in formula (1) and formula (2). For example, when X 1 and X 2 When the groups are each independently a connecting group provided by benzene, the structural formulas of formula (1) and formula (2) can be respectively That is, the benzene ring and the imidazole ring share two pairs of carbon atoms.

[0035] In the present invention, C 4 -C 10 The cycloalkane may be, for example, cyclobutane, cyclopentane, cyclohexane, cycloheptane, cyclooctane, cyclononane or cyclodecane.

[0036] In the present invention, C 1 -C 8 The chain alkane can be, for example, methane, ethane, n-propane, isopropane, butane, pentane, hexane, heptane, octane. In some embodiments, C 1 -C 8 The alkane may be a C 1 -C 8 The halogen atom may be selected from a fluorine atom, a chlorine atom and a bromine atom.

[0037] In the present invention, C 2 -C 8 The olefin may be, for example, ethylene, propylene, butene, pentene, hexene, heptene, or octene.

[0038] In the present invention, the halogen may be selected from, for example, fluorine, chlorine and bromine.

[0039] In the present invention, C 1 -C 4 The alkyl group may be, for example, methyl, ethyl, n-propyl, isopropyl, n-butyl, sec-butyl, isobutyl, or tert-butyl.

[0040] In the present invention, C 1 -C 4 The haloalkyl group may be, for example, a halomethyl group, a haloethyl group, a halopropyl group, a haloisopropyl group, a halobutyl group, a halosec-butyl group, a haloisobutyl group, or a halotert-butyl group; 1 -C 4 The halogen atom in the haloalkyl group may be, for example, a fluorine atom, a chlorine atom, or a bromine atom.

[0041] According to the present invention, preferably, in some embodiments, the X 1 and X 2 The groups are each independently a connecting group provided by at least one compound selected from benzene, diphenyl, terphenyl, bridged phenyl, pterene and a condensed aromatic hydrocarbon containing 1 to 10 benzene rings; preferably, the X 1 and X 2 The groups are each independently a connecting group provided by at least one compound selected from benzene, biphenyl, bridged benzene, pterene and naphthalene; more preferably, the bridged benzene has a structure shown in formula (3), formula (4) or formula (5), wherein R 1 , R 3 , R 4 are each independently selected from one of an oxygen atom, a sulfur atom, a carbonyl group, a sulfonyl group, a methylene group and a halogen-substituted methylene group; and R 2 Selected from containing heteroaromatic rings;

[0042]

[0043] In the present invention, the heteroaromatic ring-containing compound may be, for example, pyridine or pyrimidine.

[0044] In the present invention, the connection positions (indicated by "dashed lines") of the structures represented by formula (3), formula (4) and formula (5) can be as follows:

[0045]

[0046] In the present invention, the connection positions include but are not limited to the above-mentioned representations; for example, any two adjacent connection positions on the same benzene ring are feasible.

[0047] According to the present invention, preferably, the X 1 and X 2 The groups are each independently selected from the following linking groups:

[0048]

[0049] wherein G is selected from a hydrogen atom, a methyl group and a trifluoromethoxy group; J is selected from an oxygen atom, a sulfur atom, a carbonyl group, a sulfonyl group, a methylene group and a methylene group substituted with a methyl group or a trifluoromethyl group; L is selected from a bromine atom, a phenyl group and a phenyl group substituted with a trifluoromethyl group; and R is selected from a hydrogen atom, a carboxyl group, a hydroxyl group and a trifluoromethyl group.

[0050] In the present invention, in some embodiments, the X 1 and X 2 The attachment positions in the group may include, but are not limited to, the attachment positions shown below:

[0051]

[0052] According to the present invention, in some embodiments, the X 2 and X 1 The molar content ratio of the group can be 0-9999, preferably 0-99; for example, it can be 0, 0.001, 0.01, 0.02, 0.03, 0.04, 0.05, 0.06, 0.07, 0.08, 0.09, 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1, 2, 3, 4, 5, 10, 20, 30, 40, 50, 60, 70, 80, 90, 99, 100, and the range of any two of the above points. In the present invention, unless otherwise specified, X in polybenzimidazole 2 and X 1 The content ratio of the structural unit or group is calculated based on the feed amount.

[0053] According to the present invention, preferably, the Y group is derived from at least one of the following compounds:

[0054]

[0055] According to the present invention, preferably, in some embodiments, the Z group is benzene, a 5-6 membered nitrogen-containing heterocyclic compound, an aromatic compound containing 2-7 benzene rings, an aromatic compound containing 1-2 nitrogen-containing heterocyclic rings and 1-4 benzene rings, C 4 -C 10 Cycloalkanes, C 1 -C 8 Alkanes, and C 2 -C 8 At least one olefinic compound provides a linking group.

[0056] According to the present invention, preferably, the Z group is a linking group selected from the following:

[0057]

[0058]

[0059] C 1 -C 8 Alkyl;

[0060] wherein M is selected from a hydrogen atom, a cyano group, a methyl group, a phenyl group, and a phenyl group substituted with a methyl group or a trifluoromethyl group; P is selected from an oxygen atom, a sulfur atom, a carbonyl group, a sulfonyl group, a cyclobutyl group, a cyclobutyl group substituted with a halogen group, a methylene group, and a methylene group substituted with a methyl group or a trifluoromethyl group; Q is selected from a bromine atom, a phenyl group, and a phenyl group substituted with a trifluoromethyl group; and T is selected from a hydrogen atom and a methyl group.

[0061] In the present invention, the connection position of the Z group is not particularly limited and can be any position on the connection group. For example, when the Z group contains a ring structure, the connection position can be a carbon atom on the ring structure; 1 -C 8 When the Z group is a chain alkyl group, the connection position can be any carbon atom in the chain alkyl group. In the present invention, the connection position of the Z group can include but is not limited to the following connection positions:

[0062]

[0063]

[0064] According to the present invention, the molar content ratio of the Z and Y groups can be 0-9999, more preferably 0-99; for example, it can be 0, 0.001, 0.01, 0.02, 0.03, 0.04, 0.05, 0.06, 0.07, 0.08, 0.09, 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1, 2, 3, 4, 5, 10, 20, 30, 40, 50, 60, 70, 80, 90, 99, 100, and the range composed of any two of the above points. In the present invention, unless otherwise specified, the content ratio of the Z and Y structural units or groups in the polybenzimidazole is calculated according to the feed amount.

[0065] In the present invention, the free volume of the polybenzimidazole can be Preferably And the pore size of the polybenzimidazole can be Preferably

[0066] In the present invention, the intrinsic viscosity of the polybenzimidazole can be 0.45-3.0 dL g-1 ; For example, it can be 0.45dL g -1 , 0.5dL g -1 , 0.6dL g -1 , 0.7dL g -1 , 0.8dL g -1 , 0.9dL g -1 , 1dL g -1 、1.1dL g -1 , 1.2dL g -1 、1.3dL g -1 、1.4dL g -1 、1.5dL g -1 , 1.6dL g -1 、1.7dL g -1 、1.8dL g -1 、1.9dL g -1 , 2.0dL g -1 , 2.1dL g -1 , 2.2dL g -1 , 2.3dL g -1 、2.4dL g -1 , 2.5dL g -1 , 2.6dL g -1 , 2.7dL g -1 , 2.8dL g -1 、2.9dL g -1 、3.0dL g -1 , and the range consisting of any two of the above points.

[0067] The preparation of polybenzimidazole is known in the art. Various preparation methods known in the art can be used to prepare the polybenzimidazole of the present invention.

[0068] In another aspect, the present invention also provides a method for preparing the polybenzimidazole described in the first aspect, the method comprising reacting at least one compound having a structure represented by formula (6) with HOOC-Y-COOH and optionally HOOC-Z-COOH;

[0069]

[0070] Wherein, the X group in formula (6) is the same as X in formula (1) and formula (2) above. 1 and / or X 2 The groups are the same, and the Y and Z groups in HOOC-Y-COOH and the optional HOOC-Z-COOH are respectively the same as the Y and Z groups defined in the above formula (1) and formula (2), and are not repeated here.

[0071] According to the preparation method of the present invention, preferably, in some embodiments, the compound having the structure shown in formula (6) is selected from at least one of the following compounds:

[0072]

[0073] Wherein, G is selected from hydrogen atom, methyl and trifluoromethoxy, i.e., -H, -CH 3 , --OCF 3 ;

[0074] J is selected from oxygen atoms, sulfur atoms, carbonyl groups, sulfonyl groups, methylene groups and methylene groups substituted with methyl or trifluoromethyl groups, for example,

[0075] L is selected from bromine atoms, phenyl groups and trifluoromethyl-substituted phenyl groups, for example, as well as

[0076] R is selected from hydrogen, carboxyl, hydroxyl and trifluoromethyl, i.e. -H, -COOH, -OH, -CF 3 .

[0077] According to the preparation method of the present invention, preferably, in some embodiments, the reaction is carried out in a solvent, more preferably, the solvent is a mixed solution of methanesulfonic acid / phosphorus pentoxide or polyphosphoric acid, further preferably a mixed solution of methanesulfonic acid / phosphorus pentoxide, the mass of phosphorus pentoxide is 2-10% of the mass of methanesulfonic acid. The concentration of the mixed monomers in the reaction system can be 3wt%-20wt%.

[0078] According to the preparation method of the present invention, preferably, in some embodiments, the ratio of the molar amount of the compound having the structure represented by formula (6) to the total molar amount of HOOC-Y-COOH and optional HOOC-Z-COOH is 1:0.6-2, preferably 1:0.8-1.2.

[0079] According to the preparation method of the present invention, preferably, in some embodiments, the reaction time can be 1-9 hours, preferably 3-5 hours. The reaction temperature can be 60-230° C., preferably 60-170° C., more preferably 100-150° C. The reaction pressure can be normal pressure.

[0080] According to the preparation method of the present invention, preferably, HOOC-Y-COOH is selected from at least one of the following compounds:

[0081]

[0082] According to the preparation method of the present invention, preferably, in some embodiments, HOOC-Z-COOH is selected from at least one of the following compounds:

[0083]

[0084]

[0085] Wherein, n is 1-8; M, P, Q, and T each refer to a substituent, which is the same as described in the first aspect and will not be repeated here.

[0086] According to the preparation method of the present invention, preferably, in some embodiments, the ratio of the molar amount of the compound having the structure shown in formula (6) to the total molar amount of HOOC-Y-COOH and optional HOOC-Z-COOH is 1:0.6-2; for example, 1:0.6, 1:0.7, 1:0.8, 1:0.9, 1:1, 1:1.1, 1:1.2, 1:1.3, 1:1.4, 1:1.5, 1:1.6, and the range of any two of the above points; preferably 1:0.8-1.2; wherein X 2 With X 1 The molar content ratio of the group can be 0-9999, preferably 0-99, for example, 0, 0.001, 0.01, 0.02, 0.03, 0.04, 0.05, 0.06, 0.07, 0.08, 0.09, 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1, 2, 3, 4, 5, 10, 20, 30, 40, 50, 60, 70, 80, 90, 99, 100, and ranges consisting of any two of the above; Z The molar content ratio of the Y group can be 0-9999, preferably 0-99, for example, 0, 0.001, 0.01, 0.02, 0.03, 0.04, 0.05, 0.06, 0.07, 0.08, 0.09, 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1, 2, 3, 4, 5, 10, 20, 30, 40, 50, 60, 70, 80, 90, 99, 100, and the range composed of any two of the above points.

[0087] In some embodiments, the polybenzimidazole of the present invention may have one of the following structures:

[0088]

[0089] In the above structures, for copolymers, the structures shown only indicate that the polymer chain segments contain the repeating structural units shown or the polymer chain segments consist of the repeating structural units shown, and do not indicate the distribution of the repeating structural units shown in the polymer chain. The present invention also provides the use of the above polybenzimidazole polymer in gas adsorption separation.

[0090] In one aspect, the present invention provides separation of CO by adsorption 2 A method for removing pollutants from a gas, wherein the polybenzimidazole described in the first aspect of the invention is used as an adsorbent.

[0091] It is unexpectedly found in the present invention that the polybenzimidazole of the present invention has a 2 It has high adsorption capacity and is suitable for N 2 and O 2 It has a low adsorption capacity, thus providing high carbon dioxide / nitrogen separation factors and high carbon dioxide / oxygen separation factors, making it possible to use it for CO 2 and selected from N 2 , O 2 or gas separation of a mixture thereof.

[0092] The present invention is not limited to a specific separation operation, but generally comprises the steps of: 2 When the polybenzimidazole of the present invention adsorbs a sufficient amount of CO 2 When the polybenzimidazole is removed and regenerated by desorption, the regenerated polybenzimidazole can be re-contaminated with CO 2 The gas mixture is contacted to adsorb CO 2 .

[0093] The present invention also provides the use of the polybenzimidazole described in the first aspect of the present invention as an adsorbent for gas adsorption separation. 2 It has high adsorption capacity and is suitable for N 2 and O 2 The polybenzimidazole of the present invention has a low adsorption capacity, so it can be used as an adsorbent for CO 2 and selected from N 2 , O 2 or gas separation of a mixture thereof.

[0094] The present invention provides a polybenzimidazole polymer having beneficial gas adsorption separation performance and excellent thermal stability, so that the polybenzimidazole polymer can be used in some gas adsorption separation applications under high temperature conditions.

[0095] In addition, the polybenzimidazole polymer of the present invention has mechanochromic properties. Mechanochromic materials refer to materials whose color, luminescence and other properties change when stimulated by external forces, such as grinding, stretching and pressing. The polybenzimidazole polymer of the present invention has a significant shift in its fluorescence emission peak under external force stimulation, thus being a mechanochromic material.

[0096] In some embodiments, the polybenzimidazole of the present invention can be used for flow monitoring of carbon dioxide-containing gas. For example, the polybenzimidazole of the present invention can be coated on the inner surface of a microchannel and placed at the end of a gas path where the carbon dioxide flow or emission needs to be monitored. When there is a slight leakage of carbon dioxide, it can absorb carbon dioxide by virtue of its adsorption performance; when the amount of carbon dioxide leakage increases, the impact of the flow causes the material to be stressed, resulting in a change in the fluorescence emission peak signal, which is captured by the detector, and then an alarm is issued.

[0097] Polybenzimidazole without tetraphenylethylene groups is generally reddish brown, while polybenzimidazole with tetraphenylethylene groups is generally yellow. The introduction of tetraphenylethylene groups increases the diversity of polybenzimidazole chromaticity and can expand the application scenarios of polybenzimidazole. Figure 4 A physical picture of a polybenzimidazole polymer not of the present invention (left side; prepared by a method similar to the examples of the present application using 3,3′,4,4′-tetraaminobiphenyl and 4,4′-diphenyl ether dicarboxylic acid in a molar ratio of 1:1.05) and the polymer of Example 4 (PBI-4, right side) is shown.

[0098] In order to make the present invention easier to understand, the present invention will be described in detail below in conjunction with embodiments, which are only illustrative and do not limit the scope of application of the present invention. It should be noted that reasonable modifications made by personnel in this professional field inspired by this patent all fall within the scope of protection of this patent.

[0099] In the following examples,

[0100] The polymerization product yield was calculated according to the following formula:

[0101] Yield = actual polymer yield ÷ theoretical polymer yield × 100%;

[0102] The theoretical yield of the polymer = the number of moles of the compound represented by formula (6) × the molar mass of the repeating unit in the polymer structure.

[0103] 3,3′,4,4′-Tetraaminobiphenyl: Sigma-Aldrich; purity: 98%;

[0104] 4,4′-diphenyl ether dicarboxylic acid: J&K Technology; purity: 98%;

[0105] 4,4′-(2,2-diphenylethylene-1,1-diyl)dibenzoic acid: Anaiji Chemical, purity 98%;

[0106] 4,4′-(1,2-diphenylethylene-1,2-diyl)dibenzoic acid: Anaiji Chemical, purity is 91%.

[0107] Example 1

[0108] A mixed monomer of 3,3′,4,4′-tetraaminobiphenyl (2.14 g), 4,4′-diphenyl ether dicarboxylic acid (1.9 g) and 4,4′-(2,2-diphenylethylene-1,1-diyl) dibenzoic acid (1.32 g) in a molar ratio of 1:0.735:0.315 was added to a methanesulfonic acid / phosphorus pentoxide solution (solvent 62 g) to form a reaction system, and the reaction was carried out at 140°C for 5 hours to obtain a reaction solution, which was introduced into water to precipitate the polymer, and then neutralized (sodium bicarbonate) and filtered to obtain the polymerization product PBI-1. Among them, the weight ratio of methanesulfonic acid to phosphorus pentoxide in the methanesulfonic acid / phosphorus pentoxide solution is 12:1, and the concentration of the mixed monomer in the reaction system is 8wt%. The yield of the polymer is 99%. The nuclear magnetic hydrogen spectrum of PBI-1 was measured in Test Example 6. Figure 1 Its structure was confirmed by H NMR spectrum.

[0109] Example 2

[0110] The method of Example 1 was followed, except that 4,4′-(2,2-diphenylethylene-1,1-diyl)dibenzoic acid was replaced with an equal molar amount of 4,4′-(1,2-diphenylethylene-1,2-diyl)dibenzoic acid. The yield of polymer PBI-2 was 99%. The H NMR spectrum of PBI-2 was measured in Test Example 6. Figure 1 Its structure was confirmed by H NMR spectrum.

[0111] Example 3

[0112] The method of Example 1 was followed, except that 4,4'-diphenyl ether dicarboxylic acid was replaced with an equal molar amount of 4,4'-(2,2-diphenylethylene-1,1-diyl) dibenzoic acid, and the reaction time was 3 h. The yield of polymer PBI-3 was 99%. Its structure was confirmed by H NMR spectrum.

[0113] Example 4

[0114] The method of Example 1 was followed, except that 4,4′-diphenyl ether dicarboxylic acid was replaced with an equal molar amount of 4,4′-(1,2-diphenylethylene-1,2-diyl) dibenzoic acid, and the reaction time was 3 h. The yield of polymer PBI-4 was 99%. Its structure was confirmed by H NMR spectrum.

[0115] Test Example 1

[0116] The thermal stability of the polymers prepared in the above examples was tested.

[0117] Test method: The test was conducted in a nitrogen atmosphere using a Q500 thermogravimetric analyzer from TA, USA. The heating rate was 10°C / min and the temperature range was 25-700°C.

[0118] Thermal decomposition temperature of polymer d5 % (temperature at which weight loss is 5% by mass) is shown in Table 1.

[0119] Table 1

[0120] PBI-1 PBI-2 PBI-3 PBI-4 <![CDATA[T d5 %(℃)]]> 490 530 510 490

[0121] Test Example 2

[0122] The free volume and pore size were determined using positron annihilation lifetime spectroscopy.

[0123] Test method: DPLS3000 is used to test the positron annihilation lifetime spectrum in an atmospheric environment at room temperature and pressure. The activity used is about 2E +6 The 22Na positron radiation source of Bq was sandwiched between the sample to form a sandwich structure. A total of 1.5 million counts were measured to obtain the positron annihilation lifetime spectrum of the sample. The system had a time resolution of 190ps, a channel width of 20ps, and a channel number of 4096. The measured positron annihilation lifetime spectrum was analyzed using the Melt 4.0 program to obtain the positron annihilation lifetime and intensity, and the free volume and pore size of the polymer.

[0124] The test results of polymer free volume and pore size are shown in Table 2.

[0125] Table 2

[0126]

[0127] Test Example 3

[0128] The isothermal adsorption properties of polybenzimidazole for gases were tested.

[0129] Test method: Micromeritics ASAP2020 was used for testing. The sample was placed in a sample tube and placed in a degassing station for high-temperature vacuum degassing. The degassed sample was weighed and placed in an analysis station to measure N 2 , O 2 and CO 2 The adsorption isotherm and desorption isotherm have pressure selection points ranging from 10 mmHg to 800 mmHg, and the desorption isotherm has pressure selection points ranging from 800 mmHg to 60 mmHg.

[0130] The test results are shown in Table 3.

[0131] Table 3

[0132]

[0133] Test Example 4

[0134] The polymers prepared in Examples 1-4 above were tested for their mechanochromic properties.

[0135] Test method: Place the polymer powder in a solid fixture (two transparent quartz plates, one of which has a groove for placing the sample), and place it in a fluorescence instrument (Edinburgh-steady-state / transient fluorescence spectrometer FLS1000) to detect the obtained fluorescence emission spectrum. Then, grind the polymer powder manually in a mortar for 30 seconds, place it in a solid fixture, and place it in the fluorescence instrument again to detect the fluorescence emission spectrum.

[0136] The peak shifts of the strongest fluorescence emission before and after polymer grinding are shown in Table 4.

[0137] Table 4

[0138]

[0139] Note: “#” indicates the emission peak is blue-shifted; “*” indicates the emission peak is red-shifted.

[0140] Test Example 5

[0141] The polymers prepared in Examples 1-4 above were tested for their intrinsic viscosity.

[0142] Test method: Dissolve PBI in concentrated sulfuric acid to a concentration of 0.6 g dL- 1 Sulfuric acid solution. Add the sulfuric acid solution into the Ubbelohde viscometer and place it in a 25°C constant temperature water bath to stabilize for 30 minutes. Measure the outflow time of the solution. Each sample is measured three times, and the time difference is no more than 1 second. The average value is recorded as t 1 , the outflow time of concentrated sulfuric acid is recorded as t 0 The formula for calculating the intrinsic viscosity [η] of PBI is as follows: Intrinsic viscosity Wherein, C is the concentration of PBI sulfuric acid solution.

[0143] The test results are shown in Table 5.

[0144] Table 5

[0145] PBI-1 PBI-2 PBI-3 PBI-4 <![CDATA[Intrinsic viscosity (dL g -1 )]]> 2.18 1.08 1.75 2.01

[0146] Test Example 6

[0147] The H NMR spectra of the polymers of Example 1 and Example 2 were tested. H NMR spectra testing method: Agilent 400-MR DD2 NMR spectrometer was used, the frequency was 400 MHz, tetramethylsilane (TMS) was used as the internal standard, and the solvent was DMSO-d 6 , the test temperature is 40℃.

[0148] The nuclear magnetic hydrogen spectra of the polymer products of Example 1 and Example 2 are as follows: Figure 1 As shown, the proton signal at the chemical shift of 13.0ppm in the spectrum can be attributed to the characteristic peak of active hydrogen in the PBI structural unit, the proton signals at 7.30ppm and 8.28ppm can be attributed to the characteristic peaks of the corresponding structural units after the polymerization of 4,4′-diphenyl ether dicarboxylic acid monomer, and the proton signals at 7.08-7.24ppm and 7.55-8.02ppm can be attributed to the characteristic peaks of the corresponding structural units after the polymerization of tetraamine monomer and tetraphenylethylene dicarboxylic acid monomer. The spectrum analysis results show that polymers PBI-1 and PBI-2 were successfully obtained.

[0149] The results of H-NMR spectrum showed that polymers PBI-1 to PBI-4 were successfully obtained.

[0150] Comparative Example 1

[0151] The data reported in the following literature are used:

[0152] Facile preparation of porous polybenzimidazole networks and adsorption behavior of CO 2 Gas, organic and water vapors, Hao Yu et al., Polym.Chem., 2013, 4, 961-968 (DOI: 10.1039 / c2py20908j)

[0153] The experiment in this document uses Autosorb iQ-MP test, and the gas adsorption isotherms are measured at room temperature, with an upper pressure limit of 1 bar. The test results are shown in Table 6.

[0154] Table 6

[0155] PBI-1' PBI-2' Separation factor (carbon dioxide / nitrogen) 12.3 9.3

[0156] Comparative Example 2

[0157] The data reported in the following literature are used:

[0158] Influence of polybenzimidazole main chain structure on H2 / CO 2 separation at elevated temperatures, Xin Li et al, Journal of MembraneScience, Volume 461, 1July 2014, Pages 59-68 (DOI: 10.1016 / j.memsci.2014.03.008)

[0159] The experiments in this paper used Kalrez TM Test, pressure 10-50psi, temperature 30-250℃. Test results are shown in Table 7.

[0160] Table 7

[0161]

[0162] The preferred embodiments of the present invention are described in detail above, but the present invention is not limited thereto. Within the technical concept of the present invention, the technical solution of the present invention can be subjected to a variety of simple modifications, including the combination of various technical features in any other suitable manner, and these simple modifications and combinations should also be regarded as the contents disclosed by the present invention and belong to the protection scope of the present invention.

Claims

1. A polybenzimidazole, characterized in that: The polybenzimidazole contains a structural unit A, wherein the structural unit A has a structure shown in formula (1); Wherein, the X1 group is a connecting group provided by an aromatic compound containing 1 to 10 benzene rings; and the Y group is a connecting group based on tetraphenylethylene; wherein, the X1 group and the Y group each independently contain or do not contain at least one substituent selected from hydroxyl, amino, cyano, halogen, C1-C4 alkyl, C1-C4 haloalkyl.

2. The polybenzimidazole according to claim 1, wherein The polybenzimidazole contains structural unit A and structural unit C, structural unit A and structural unit D, or structural unit A, structural unit B, structural unit C and structural unit D; The structural unit A has a structure shown in formula (1), the structural unit B has a structure shown in formula (2), the structural unit C has a structure shown in formula (1-1), and the structural unit D has a structure shown in formula (2-2): wherein the X1 and X2 groups are each independently a linking group provided by an aromatic compound containing 1 to 10 benzene rings; the Y group is a linking group based on tetraphenylethylene; and the Z group is an aromatic hydrocarbon containing 1 to 10 benzene rings, a heteroaromatic hydrocarbon containing 1 to 10 heterocyclic rings, an aromatic hydrocarbon containing 1 to 3 heterocyclic rings and 1 to 8 benzene rings, a C4-C 10 A connecting group is provided by at least one compound selected from cycloalkanes, C1-C8 alkanes, and C2-C8 olefins; wherein the X1, X2, Y, and Z groups each independently contain or do not contain at least one substituent selected from hydroxyl, amino, cyano, halogen, C1-C4 alkyl, and C1-C4 haloalkyl.

3. The polybenzimidazole according to claim 1, wherein The polybenzimidazole contains a structural unit A and an optional structural unit B, wherein the structural unit A has a structure shown in formula (1) and the structural unit B has a structure shown in formula (2); wherein the X1 and X2 groups are each independently a linking group provided by an aromatic compound containing 1 to 10 benzene rings; the Y group is a linking group based on tetraphenylethylene; and the Z group is an aromatic hydrocarbon containing 1 to 10 benzene rings, a heteroaromatic hydrocarbon containing 1 to 10 heterocyclic rings, an aromatic hydrocarbon containing 1 to 3 heterocyclic rings and 1 to 8 benzene rings, a C4-C 10 A connecting group is provided by at least one compound selected from cycloalkanes, C1-C8 alkanes, and C2-C8 olefins, and when the structural unit B is present, Z and Y are different; wherein, at least one substituent selected from hydroxyl, amino, cyano, halogen, C1-C4 alkyl, and C1-C4 haloalkyl is present or absent on the X1, X2, Y and Z groups independently.

4. The polybenzimidazole according to any one of claims 1 to 3, wherein The X1 and X2 groups are each independently a linking group provided by at least one compound selected from benzene, biphenyl, terphenyl, bridged benzene, pterygene and condensed aromatic hydrocarbons containing 1 to 10 benzene rings; preferably, the X1 and X2 groups are each independently a linking group provided by at least one compound selected from benzene, biphenyl, bridged benzene, pterygene and naphthalene; more preferably, the bridged benzene has a structure shown in formula (3), formula (4) or formula (5), wherein R1, R3 and R4 are each independently selected from oxygen atoms, sulfur atoms, carbonyl groups, sulfonyl groups, methylene groups and halogen-substituted methylene groups; and R2 is selected from heteroaromatic rings; 5. The polybenzimidazole according to any one of claims 1 to 4, wherein The X1 and X2 groups are each independently selected from the following linking groups: wherein G is selected from a hydrogen atom, a methyl group and a trifluoromethoxy group; J is selected from an oxygen atom, a sulfur atom, a carbonyl group, a sulfonyl group, a methylene group and a methylene group substituted with a methyl group or a trifluoromethyl group; L is selected from a bromine atom, a phenyl group and a phenyl group substituted with a trifluoromethyl group; and R is selected from a hydrogen atom, a carboxyl group, a hydroxyl group and a trifluoromethyl group.

6. The polybenzimidazole according to any one of claims 2 to 5, wherein The Z group is benzene, a 5-6 membered nitrogen-containing heterocyclic compound, an aromatic compound containing 2-7 benzene rings, an aromatic compound containing 1-2 nitrogen-containing heterocyclic rings and 1-4 benzene rings, a C4-C 10 A linking group provided by a compound of at least one of cycloalkane, C1-C8 alkane and C2-C8 alkene; Preferably, the Z group is a linking group selected from the following: C1-C8 alkyl; wherein M is selected from a hydrogen atom, a cyano group, a methyl group, a phenyl group, and a phenyl group substituted with a methyl group or a trifluoromethyl group; P is selected from an oxygen atom, a sulfur atom, a carbonyl group, a sulfonyl group, a cyclobutyl group, a cyclobutyl group substituted with a halogen group, a methylene group, and a methylene group substituted with a methyl group or a trifluoromethyl group; Q is selected from a bromine atom, a phenyl group, and a phenyl group substituted with a trifluoromethyl group; and T is selected from a hydrogen atom and a methyl group.

7. The polybenzimidazole according to any one of claims 1 to 6, wherein The Y group is derived from at least one of the following compounds:

8. The polybenzimidazole according to any one of claims 1 to 7, wherein The intrinsic viscosity of the polybenzimidazole is 0.45-3.0 dL g -1 and / or, The molar content ratio of X2 to X1 groups in the polybenzimidazole is 0-9999, preferably 0-99; and / or, The molar content ratio of the Z group to the Y group in the polybenzimidazole is 0-9999, preferably 0-99.

9. The polybenzimidazole according to any one of claims 1 to 8, wherein The free volume of the polybenzimidazole is Preferably And the pore size of the polybenzimidazole is Preferably 10. The polybenzimidazole according to any one of claims 1 to 9, wherein The polybenzimidazole has mechanochromic properties.

11. A method for preparing a polybenzimidazole according to any one of claims 1 to 10, wherein the method comprises reacting at least one compound having a structure represented by formula (6) with HOOC-Y-COOH and optionally HOOC-Z-COOH; in, The X group in formula (6) is the same as the X1 and / or X2 group defined in any one of claims 1 to 10, and the Y and Z groups in HOOC-Y-COOH and the optional HOOC-Z-COOH are each the same as the Y and Z groups defined in any one of claims 1 to 10.

12. The method according to claim 11, wherein the reaction is carried out in a solvent, preferably, the solvent is a mixed solution of methanesulfonic acid / phosphorus pentoxide or polyphosphoric acid, more preferably a mixed solution of methanesulfonic acid / phosphorus pentoxide, and the mass of phosphorus pentoxide is 2-10% of the mass of methanesulfonic acid.

13. The method according to claim 11 or 12, wherein the ratio of the molar amount of the compound having the structure shown in formula (6) to the total molar amount of HOOC-Y-COOH and optional HOOC-Z-COOH is 1:0.6-2, preferably 1:0.8-1.

2.

14. A method for separating CO2 gas by adsorption, wherein the polybenzimidazole according to any one of claims 1 to 10 is used as an adsorbent.

15. The method according to claim 14, wherein the CO2 gas is separated from a gas selected from N2, O2 or a mixture thereof by adsorption.

16. Use of the polybenzimidazole according to any one of claims 1 to 10 as an adsorbent for gas adsorption separation.

17. The use according to claim 16, wherein the polybenzimidazole is used as an adsorbent for separating CO2 gas from a gas selected from N2, O2 or a mixture thereof.

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