TWI623512B - Tetramine compound, method for fabricating tetramine compound, polybenzimidazole, method for fabricating polybenzimidazole, proton exchange membrane formed from polybenzimidazole, fuel cell including proton exchange membrane - Google Patents

Abstract

a tetraamine compound represented by formula (I) or formula (II),

Formula (II) wherein R ₁ is an alkyl group, a haloalkyl group or a haloalkoxy group.

Description

Teamine compound and preparation method thereof, polybenzimidazole and preparation method thereof, proton exchange membrane made of polybenzimidazole, fuel cell containing proton exchange membrane

The present invention relates to a tetraamine monomer and a process for the preparation thereof; a polybenzimidazole prepared from the tetraamine monomer and a process for the preparation thereof; a proton exchange membrane made of the polybenzimidazole; A fuel cell comprising this proton exchange membrane.

Proton Exchange Membrane Fuel Cell (PEMFC) is a device that electrochemically converts chemical energy into electrical energy. The proton exchange membrane fuel cell contains a high molecular proton exchange membrane as a proton conduction medium, and thus a polymer proton exchange membrane as a solid electrolyte is one of important components in a proton exchange membrane fuel cell.

Polybenzimidazoles (PBI) have excellent thermal stability, chemical stability and mechanical strength, and have high proton conductivity at high temperatures after doping with phosphoric acid. Therefore, polybenzimidazole is widely used in high-temperature proton exchange membrane fuel cells using phosphoric acid as a proton transfer medium.

However, the development of polybenzimidazole materials has been limited because of the small monomer type and the difficulty of polymerization. In the monomer part, the synthesis of the diacid monomer is relatively easy, so many research teams have carried out the synthesis of the novel diacid monomer. In contrast, fewer teams have studied the synthesis of novel tetraamine monomers. In the polymer part, polybenzimidazole is prematurely precipitated or gelled due to poor solubility during polymerization, resulting in polybenzimidazole not being soluble in organic solvents for subsequent film forming. .

In addition, when the high-temperature proton exchange membrane fuel cell is operated, if oxygen cannot be completely reduced, H ₂ O ₂ may be generated. H ₂ O ₂ will be decomposed into a catalyst. OH or. OOH radicals, while free radicals are highly active and unstable. Therefore, the free radicals attack the polymer chain, causing the polymer chain to degrade, thereby causing the strength of the proton exchange membrane to decrease, resulting in damage of the membrane electrode assembly (Membrane electrode assembly).

One aspect of the present invention provides a tetraamine compound represented by formula (I) or formula (II).

Wherein R ₁ is an alkyl group, a haloalkyl group or a haloalkoxy group.

In certain embodiments of the invention, the R ₁ system of the tetraamine compound is -C _n H _2n+1 , -C _n H _2n+1-m X _m or -OC _n H _2n+1-m X _m ; Halogen; n is an integer from 1 to 4; m is an integer from 1 to 2n+1.

Another aspect of the present invention provides a process for producing a tetraamine compound, comprising the steps of: (a) reacting a compound represented by the formula (VI) with a deuteration reagent to form a compound represented by the formula (VII),

Wherein R ₁ is an alkyl group, a haloalkyl group or a haloalkoxy group; an R ₃ -based alkyl group or a haloalkyl group; (b) reacting a compound represented by the formula (VII) with a nitrating agent to form a formula (VIII) Compound represented,

(c) subjecting a compound represented by the formula (VIII) to a deuteration reaction to form a compound represented by the formula (IX),

(d) subjecting a compound represented by the formula (IX) to a reduction reaction to form a tetraamine compound represented by the formula (I),

Another aspect of the present invention provides a method for producing a tetraamine compound, comprising the steps of: (i) reacting a compound represented by the formula (VI) with a deuteration reagent and a nitrating reagent to form a compound represented by the formula (VIII) compound of,

Wherein R ₁ is an alkyl group, a haloalkyl group or a haloalkoxy group; an R ₃ -based alkyl group or a haloalkyl group; (ii) a deuteration reaction of a compound represented by the formula (VIII) to form a formula (IX) Compound represented,

(iii) subjecting a compound represented by the formula (IX) to a reduction reaction to form a tetraamine compound represented by the formula (I),

Another aspect of the present invention provides a polybenzimidazole represented by formula (IV) or formula (V),

Wherein R ₁ is an alkyl group, a haloalkyl group or a haloalkoxy group; R ₂ is a divalent linking group comprising an aryl group or a heteroaryl group; and n is an integer of 90 to 500.

In certain embodiments of the invention, the _{polybenzimidazole-based,} R _{1 -C n H 2n + 1, -C} n H 2n + 1-m X m or _{-OC n H 2n + 1-m} X m; X Halogen; n is an integer from 1 to 4; m is an integer from 1 to 2n+1.

In certain embodiments of the invention, the R2 system of polybenzimidazole The asterisk indicates the connection key.

Another aspect of the present invention provides a process for producing a polybenzimidazole comprising the steps of polymerizing a tetraamine monomer represented by the formula (I) with a diacid monomer represented by the formula (III), and Forming a polybenzimidazole represented by the formula (IV); or

The tetraamine monomer represented by the formula (II) is polymerized with the diacid monomer represented by the formula (III) to form a polybenzimidazole represented by the formula (V).

Wherein R ₁ is an alkyl group, a haloalkyl group or a haloalkoxy group; R ₂ is a divalent linking group comprising an aryl group or a heteroaryl group; and n is an integer of 90 to 500.

Another aspect of the invention provides a proton exchange membrane comprising a polybenzimidazole as described above.

Another aspect of the present invention provides a fuel cell comprising: an anode catalyst layer, a cathode catalyst layer, and the proton exchange membrane described above, wherein the proton exchange membrane is disposed in the anode catalyst layer and the cathode catalyst layer between.

100‧‧‧membrane electrode group for fuel cell

110‧‧‧First fuel gas diffusion layer

120‧‧‧Anode catalyst layer

130‧‧‧Proton exchange membrane

140‧‧‧ Cathode catalyst layer

150‧‧‧Second fuel gas diffusion layer

Fig. 1 is a schematic view showing the synthesis route of polybenzimidazole according to an embodiment of the present invention.

Fig. 2 is a schematic view showing a membrane electrode assembly of a fuel cell according to an embodiment of the present invention.

Figure 3 is a schematic view showing the synthesis route of the tetraamine monomer in the embodiment of the present invention.

Figure 4 is a hydrogen nuclear magnetic resonance spectrum of 4,4',5,5'-tetraamino-2,2'-dimethylbiphenyl (5).

Figure 5 is a mass spectrum of 4,4',5,5'-tetraamino-2,2'-dimethylbiphenyl (5).

Figure 6 is a hydrogen nuclear magnetic resonance spectrum of 4,4',5,5'-tetraamino-2,2'-bis(trifluoromethoxy)biphenyl (10).

Figure 7 is a mass spectrum of 4,4',5,5'-tetraamino-2,2'-bis(trifluoromethoxy)biphenyl (10).

Figure 8 is a hydrogen nuclear magnetic resonance spectrum of 4,4',5,5'-tetraamino-2,2'-bis(trifluoromethyl)biphenyl (14).

Figure 9 is a mass spectrum of 4,4',5,5'-tetraamino-2,2'-bis(trifluoromethyl)biphenyl (14).

Fig. 10 is a view showing the results of oxidation stability test of the polybenzimidazole film of the embodiment of the present invention.

Fig. 11A and Fig. 11B are schematic diagrams showing the relationship between the doping amount of phosphoric acid and the time of the polybenzimidazole film.

Figure 12 is a schematic diagram showing the relationship between proton conductivity and temperature of a polybenzimidazole film.

13A and 13B are schematic diagrams showing the polarization curves of the fuel cells of the polybenzimidazole film (P1) in different phosphoric acid doping amounts and different film thicknesses according to an embodiment of the present invention.

14A and 14B are schematic diagrams showing the polarization curves of the fuel cells of the polybenzimidazole film (P2) in different phosphoric acid doping amounts and different film thicknesses according to an embodiment of the present invention.

Figure 15 is a polybenzimidazole film (P1), a polybenzimidazole film (P2), and a poly-2,2'-(m-phenyl)-5,5'-bibenzimidazole according to an embodiment of the present invention. Schematic diagram of the fuel cell polarization curve of m- PBI) film.

In order to make the description of the present invention more detailed and complete, the embodiments of the present invention are described in detail with reference to the accompanying drawings. It is not intended to limit the invention. The terms used throughout the specification and the scope of the patent application usually have each word used in this field. The usual meaning. Certain terms used to describe the disclosure are discussed below or elsewhere in this specification to provide additional guidance to those skilled in the art in the description of the disclosure.

Tetraamine monomer

In certain embodiments of the invention, the tetraamine monomer is represented by formula (I) or formula (II):

Wherein R ₁ is an alkyl group, a haloalkyl group or a haloalkoxy group.

It should be understood that the tetraamine monomer represented by the formula (I) includes

It should be understood that the tetraamine monomer represented by the formula (II) includes

In certain embodiments of the invention, the R ₁ of the tetraamine monomer has a functional group that is hydrophobic in nature and has some steric hindrance. Certain technical effects of the present invention are achieved by R ₁ having a functional group having hydrophobic properties and a certain space barrier, as will be described in more detail below. Thus according to certain embodiments of the invention, the R ₁ functional group has hydrophobic properties and has a suitable steric hindrance.

In certain embodiments of the invention, the R ₁ system of the tetraamine monomer is -C _n H _2n+1 , -C _n H _2n+1-m X _m or -OC _n H _2n+1-m X _m ;X Halogen; n is an integer from 1 to 4; m is an integer from 1 to 2n+1. In certain embodiments, R _{1 is,} for example, -CH ₃ , -CF ₃ or -OCF ₃ . In certain embodiments, the halogen can be fluorine, chlorine, bromine or iodine.

In some embodiments of the present invention, a method of producing a tetraamine monomer, comprising the steps of: (a) reacting a compound represented by the formula (VI) with a deuteration reagent to form a compound represented by the formula (VII),

Wherein R ₁ is an alkyl group, a haloalkyl group or a haloalkoxy group; an R ₃ -based alkyl group or a haloalkyl group; (b) a compound represented by the formula (VII) is reacted with a nitrating reagent to form a formula (VIII) Compound represented,

(c) subjecting a compound represented by the formula (VIII) to a deuteration reaction to form a compound represented by the formula (IX),

(d) subjecting a compound represented by the formula (IX) to a reduction reaction to form a tetraamine monomer represented by the formula (I),

In certain embodiments of the invention, the deuteration reagent of step (a) above comprises acetic anhydride or trifluoroacetic anhydride. In certain embodiments of the invention, the nitrating agent of step (b) above comprises a mixture of sulfuric acid and nitric acid or a nitrate such as sodium nitrate or potassium nitrate. In some embodiments of the present invention, the desulfurization reaction of the aforementioned step (c) comprises reacting a methanol solution containing potassium hydroxide, an aqueous solution containing hydrochloric acid or an aqueous methanol solution containing potassium carbonate. In certain embodiments of the invention, the reduction of step (d) described above comprises the addition of ammonium formate and Pd/C for reaction.

In certain embodiments, in the foregoing method of preparing a tetraamine monomer, R ₁ may be haloalkyl or haloalkoxy, and the haloalkyl group may be fluoroalkyl, chloroalkyl, bromoalkyl or iodine. The haloalkoxy group may be a fluoroalkoxy group, a chloroalkoxy group, a bromoalkoxy group or an iodoalkoxy group, for example, -CH ₃ , -CF ₃ or -OCF ₃ . In certain embodiments, in the foregoing method of preparing a tetraamine monomer, R ₃ may be a haloalkyl group, and the haloalkyl group may be a fluoroalkyl group, a chloroalkyl group, a bromoalkyl group or an iodoalkyl group, for example, CH ₃ or -CF ₃ .

In some embodiments of the present invention, another method of preparing a tetraamine monomer comprises the steps of: (i) reacting a compound represented by the formula (VI) with a deuteration reagent and a nitrating reagent to form a formula (VIII) ) the compound represented,

Wherein R ₁ is an alkyl group, a haloalkyl group or a haloalkoxy group; an R ₃ -based alkyl group or a haloalkyl group; (ii) a deuteration reaction of a compound represented by the formula (VIII) to form a formula (IX) Compound represented,

(iii) subjecting a compound represented by the formula (IX) to a reduction reaction to form a tetraamine monomer represented by the formula (I),

In certain embodiments of the invention, the deuteration reagent of step (i) above comprises acetic anhydride or trifluoroacetic anhydride. In certain embodiments of the invention, the nitrating agent of step (i) above comprises a mixture of sulfuric acid and nitric acid or a nitrate such as sodium nitrate or potassium nitrate. In some embodiments of the present invention, the desulfurization reaction of the aforementioned step (ii) comprises reacting a methanol solution containing potassium hydroxide, an aqueous solution containing hydrochloric acid or an aqueous methanol solution containing potassium carbonate. In certain embodiments of the invention, the reduction of step (iii) above comprises the addition of ammonium formate and Pd/C for reaction.

In certain embodiments, in the foregoing method comprising the steps (i), (ii), (iii) for preparing a tetraamine monomer, R ₁ may be a haloalkyl group or a haloalkoxy group, and the haloalkyl group may be A fluoroalkyl group, a chloroalkyl group, a bromoalkyl group or an iodoalkyl group; this haloalkoxy group may be a fluoroalkoxy group, a chloroalkoxy group, a bromoalkoxy group or an iodoalkoxy group, for example, -CH ₃ , CF ₃ or -OCF ₃ . In certain embodiments, in the other method of preparing a tetraamine monomer, R ₃ may be a haloalkyl group, and the haloalkyl group may be a fluoroalkyl group, a chloroalkyl group, a bromoalkyl group or an iodoalkyl group, for example. Is -CH ₃ or -CF ₃ .

Diacid monomer

In certain embodiments of the invention, the diacid monomer is represented by formula (II): Formula (II)

Wherein R 2 is a divalent linking group comprising an aryl or heteroaryl group.

In certain embodiments of the present invention, R2-based acid monomer comprising C ₅ -C ₃₀ aryl or C ₅ -C ₃₀ heteroaryl groups of the divalent linking group.

In certain embodiments of the invention, the diacid monomer is, for example, a

Polybenzimidazole

In certain embodiments of the invention, the polybenzimidazole is represented by formula (IV) or formula (V),

Wherein R ₁ is an alkyl group, a haloalkyl group or a haloalkoxy group; R ₂ is a divalent linking group comprising an aryl group or a heteroaryl group; and n is an integer of 90 to 500.

It should be understood that the polybenzimidazole represented by the formula (IV) includes

It should be understood that the polybenzimidazole represented by the formula (V) includes

In certain embodiments of the invention, the _{polybenzimidazole-based,} R _{1 -C n H 2n + 1, -C} n H 2n + 1-m X m or _{-OC n H 2n + 1-m} X m; X Halogen; n is an integer from 1 to 4; m is an integer from 1 to 2n+1. In certain embodiments, the halogen can be fluorine, chlorine, bromine or iodine.

In certain embodiments of the invention, the polybenzimidazole-based R2 comprises a C ₅ -C ₃₀ aryl or C ₅ -C ₃₀ heteroaryl groups of the divalent linking group.

In certain embodiments of the invention, the R2 system of polybenzimidazole The asterisk indicates the connection key.

Polybenzimidazole preparation method

In some embodiments of the present invention, a method for producing a polybenzimidazole comprises the steps of: polymerizing a tetraamine monomer represented by the formula (I) with a diacid monomer represented by the formula (III) to form a polybenzimidazole represented by the formula (IV); or

The tetraamine monomer represented by the formula (II) is polymerized with the diacid monomer represented by the formula (III) to form a polybenzimidazole represented by the formula (V).

Formula (III)

Wherein R ₁ is an alkyl group, a haloalkyl group or a haloalkoxy group; R ₂ is a divalent linking group comprising an aryl group or a heteroaryl group; and n is an integer of 90 to 500.

Please refer to FIG. 1 , which is a schematic diagram of the synthesis route of polybenzimidazole according to some embodiments of the present invention. In some embodiments of the present invention, a mixed solution of methanesulfonic acid (MSA) and phosphorus pentoxide (P ₂ O ₅ ) (10:1, weight ratio (w/w)) (Eaton's reagent) was used as a solvent, and the polymerization of polybenzimidazole was carried out with an equimolar tetraamine monomer and a diacid monomer. In certain embodiments of the invention, the polymerization is carried out with 4,4',5,5'-tetraamino-2,2'-dimethylbiphenyl (5) and 4,4'-diphenyl ether dicarboxylic acid. The reaction produces polybenzimidazole (P1); in certain embodiments of the invention, 4,4',5,5'-tetraamino-2,2'-bis(trifluoromethoxy)biphenyl (10) Polymerization with 4,4'-diphenylether dicarboxylic acid to produce polybenzimidazole (P2); in certain embodiments of the invention, 4,4',5,5'-tetraamino -2,2'-bis(trifluoromethyl)biphenyl (14) is polymerized with 4,4'-diphenyl ether dicarboxylic acid to produce polybenzimidazole (P3). As a comparative example, polybenzimidazole (P4) was obtained by polymerization of 3,3',4,4'-tetraaminobiphenyl (TAB) with 4,4'-diphenylether dicarboxylic acid.

The fuel cell

Please refer to FIG. 2, which is a schematic diagram of a membrane electrode assembly of a fuel cell according to an embodiment of the present invention. The membrane electrode assembly 100 of the fuel cell includes a first fuel gas diffusion layer 110, an anode catalyst layer 120, a proton exchange membrane 130, a cathode catalyst layer 140, and a second fuel gas diffusion layer 150. The proton exchange membrane 130 is disposed between the anode catalyst layer 120 and the cathode catalyst layer 140, and the proton exchange membrane 130 is made of the aforementioned polybenzimidazole. The anode catalyst layer 120 is located between the first fuel gas diffusion layer 110 and the proton exchange membrane 130. The cathode catalyst layer 140 is located between the second fuel gas diffusion layer 150 and the proton exchange membrane 130.

In some embodiments of the present invention, the proton exchange membrane made of the aforementioned polybenzimidazole is doped with phosphoric acid, and the phosphoric acid doping amount is between 90 and 210% by weight, for example, 110% by weight, 130% by weight. %, 150% by weight, 170% by weight or 190% by weight.

It should be understood that although the membrane electrode assembly 100 of the fuel cell shown in FIG. 3 is taken as an example in the present embodiment, the present invention is not limited thereto, that is, in other embodiments, the membrane electrode assembly of the fuel cell. It is also possible to have other layers.

In some embodiments of the present invention, the proton exchange membrane in the membrane electrode assembly of the fuel cell has a membrane thickness of 20 μm to 150 μm, for example, 30 μm, 40 μm, 50 μm, 60 μm, 70 μm, 80 μm, 90 μm, 100 μm, 110 μm, 120 μm, 130 μm or 140 μm. Proton exchange membrane during fuel cell operation When the film thickness is more than 150 μm, the ion transmission distance is too long and the internal resistance is too large. However, when the film thickness of the proton exchange membrane is less than 20 μm, the mechanical strength of the proton exchange membrane is too low, and there is a risk of cracking.

Hereinafter, the present invention will be described in detail by explaining examples and comparative examples of the invention. However, the invention is not limited to the following examples.

Please refer to FIG. 3, which is a schematic diagram of a synthetic route of a tetraamine monomer according to an embodiment of the present invention. In certain embodiments of the invention, 4,4',5,5'-four is prepared using 4,4'-diamino-2,2'-dimethylbiphenyl (1) as a starting material. Amino-2,2'-dimethylbiphenyl (5). In certain embodiments of the invention, 4,4',5 is prepared using 4,4'-diamino-2,2'-bis(trifluoromethoxy)biphenyl (6) as a starting material. , 5'-tetraamino-2,2'-bis(trifluoromethoxy)biphenyl (10). In certain embodiments of the invention, 4,4',5 is prepared using 4,4'-diamino-2,2'-bis(trifluoromethyl)biphenyl (11) as a starting material. 5'-Tetraamino-2,2'-bis(trifluoromethyl)biphenyl (14).

Example 1: Preparation of 4,4',5,5'-tetraamino-2,2'-dimethylbiphenyl (5)

5.00 g (23.55 mmol) of 4,4'-diamino-2,2'-dimethylbiphenyl (1) was ground into a powder, and then vigorously stirred in 337 mL of acetic anhydride, and reacted at room temperature for 24 hours. . After the completion of the reaction, the mixture was directly filtered, and the precipitate was collected and washed with water to neutral. After drying, 6.79 g of a white solid (yield: 97%), that is, 4,4'-diethylamino-2,2'-dimethyl Benzene (2).

Determination of 4,4'-diamino-2,2'-dimethyl-biphenyl acetyl (2) the melting point, nuclear magnetic resonance spectroscopy and hydrogen ^{(Proton nuclear magnetic resonance spectrum, 1} H NMR), carbon nuclear magnetic resonance spectroscopy ( Carbon-13 nuclear magnetic resonance spectrum, ¹³ C NMR) and electron free mass spectrometry (EIMS) were analyzed and identified. In the symbols shown below, s refers to a singlet (Singlet), d refers to a doublet (Doublet), t refers to a triplet (Triplet), q refers to a quartet (Quartet), and m refers to a multiplet (Multiplet). Mp: 288~290 °C. ^{1 H NMR (600MHz, DMSO- d} 6, δ, ppm): 1.96 (s, 6H), 2.04 (s, 6H), 6.95 (d, J = 8.4Hz, 2H), 7.42 (dd, J 1 = 8.4 Hz, J ₂ = 1.8 Hz, 2H), 7.48 (d, J = 1.8 Hz, 2H), 9.88 (s, 2H). ¹³ C NMR (150 MHz, DMSO- d ₆ , δ, ppm): 19.8, 24.0, 116.4, 120.2, 129.5, 135.5, 135.6, 138.2, 168.2. EIMS (m / z): Theory _{(C 18 H 20 N 2 O} 2) is 296.2; 296.2 analysis values.

4.72 g (15.93 mmol) of 4,4'-diethylamino-2,2'-dimethylbiphenyl (2) and 22 mL of 96% by weight sulfuric acid were added to a 100 mL three-necked round bottom flask and stirred until full. After dissolution, the temperature was lowered to 0 to 5 ° C for 30 minutes, and then 2 mL of 65% by weight of nitric acid was slowly dropped into the dosing funnel. After the completion of the addition, the reaction was carried out at 0 to 5 ° C for 2 hours, followed by the reaction at room temperature for 2 hours. After the reaction was completed, the solution was poured into ice water and stirred, and then the precipitate was collected and washed with water until neutral. The crude product was recrystallized from acetone and dried to give 1.47 g of a yellow solid (yield: 40%), ie, 4,4'-diethylamino-2,2'-dimethyl-5,5'- Nitrobiphenyl (3).

The melting point of 4,4'-diethylamino-2,2'-dimethyl-5,5'-dinitrobiphenyl (3) was determined and subjected to hydrogen nuclear magnetic resonance spectroscopy (Proton nuclear magnetic resonance spectrum, ¹ H NMR), carbon-13 nuclear magnetic resonance spectrum ( ¹³ C NMR) and electron free mass spectrometry (EIMS) were analyzed and identified. Mp: 248~251°C. ^{1 H NMR (600MHz, DMSO- d} 6, δ, ppm): 2.09 (s, 6H), 2.10 (s, 6H), 7.64 (s, 2H), 7.74 (s, 2H), 10.28 (s, 2H) . ¹³ C NMR (150 MHz, DMSO- d ₆ , δ, ppm): 19.7, 23.5, 125.6, 126.1, 130.9, 134.8, 139.9, 142.9, 168.6. EIMS (m / z): Theory _{(C 18 H 18 N 4 O} 6) is 386.1; 386.2 analysis values.

4.40 g (11.39 mmol) of 4,4'-diethylamino-2,2'-dimethyl-5,5'-dinitrobiphenyl (3) and 40 mL of methanol were added to a 100 mL three-necked circle. The bottom flask was stirred uniformly with a magnet, and then slowly added potassium hydroxide methanol solution (2.16 g of potassium hydroxide in 10 mL of methanol), and then 1.20 g of potassium hydroxide was added thereto, and the reaction was heated to reflux for 6 hours. After the reaction was completed, the solution was poured into water while the temperature of the solution was lowered to room temperature, and the precipitate was collected and washed with water until neutral. After drying, 3.39 g of a yellow solid (yield: 98%), that is, 4,4'-diamino- 2,2'-Dimethyl-5,5'-dinitrobiphenyl (4).

The melting point of 4,4'-diamino-2,2'-dimethyl-5,5'-dinitrobiphenyl (4) was determined and subjected to hydrogen nuclear magnetic resonance spectroscopy (Proton nuclear magnetic resonance spectrum, ¹ H NMR). ), carbon nuclear magnetic resonance spectrum ( ¹³ C NMR) and electron free mass spectrometry (EIMS) were analyzed and identified. Mp:>300 °C. ^{1 H NMR (600MHz, DMSO- d} 6, δ, ppm): 1.96 (s, 6H), 6.91 (s, 2H), 7.40 (s, 4H), 7.64 (s, 2H). ¹³ C NMR (150 MHz, DMSO- d ₆ , δ, ppm): 19.9, 119.2, 125.7, 127.3, 128.4, 145.4, 145.5. EIMS ( m/z ): Theory (C ₁₄ H ₁₄ N ₄ O ₄ ) 3021.

1.37 g (5.23 mmol) of 4,4'-diamino-2,2'-di Methyl-5,5'-dinitrobiphenyl (4), 24 mL of ethyl acetate, 3.4 g of ammonium formate, 24 mL of ethanol, and 0.40 g of 10% by weight of Pd/C were sequentially added to a 100 mL Erlenmeyer flask. The reaction was stirred with a magnet at room temperature for 24 hours. After completion of the reaction, the precipitate was removed by filtration through diatomaceous earth, and the filtrate was poured into a liquid separation bottle, washed with water until neutral, and the organic layer was collected, and then anhydrous sodium sulfate was added to remove water, and then the solvent was removed by a vacuum concentrator. The initial product was purified by recrystallization from deionized water, and after drying, 0.45 g of a skin color solid (yield: 41%), that is, 4,4',5,5'-tetraamino-2,2'-dimethyl Biphenyl (5).

Determination of the melting point of 4,4',5,5'-tetraamino-2,2'-dimethylbiphenyl (5), and magnetic resonance spectroscopy (Proton nuclear magnetic resonance spectrum, ¹ H NMR), carbon nuclear magnetic Resonance spectrum (Carbon-13 nuclear magnetic resonance spectrum, ¹³ C NMR), electron free mass spectrometry (EIMS) and elemental analysis were analyzed and identified. Figures 4 and 5 are hydrogen nuclear magnetic resonance spectra and mass spectra of 4,4',5,5'-tetraamino-2,2'-dimethylbiphenyl (5), respectively. Mp: 107~108 °C. ^{1 H NMR (600MHz, DMSO- d} 6, δ, ppm): 1.77 (s, 6H), 4.23 (s, 8H), 6.18 (s, 2H), 6.35 (s, 2H). ¹³ C NMR (150 MHz, DMSO- d ₆ , δ, ppm): 18.8, 115.9, 116.6, 123.6, 131.2, 132.1, 133.3. EIMS ( m/z ): Theory (C ₁₄ H ₁₈ N ₄ ): 242.2; Elemental analysis: theoretical value (C ₁₄ H ₁₈ N ₄ ) is C, 69.39%; H, 7.49%; N, 23.12%. The analytical value is C, 67.86%; H, 7.28%; N: 22.47%.

Example 2: Preparation of 4,4',5,5'-tetraamino-2,2'-bis(trifluoromethoxy)biphenyl (10)

5.00 g (14.20 mmol) of 4,4'-diamino-2,2'- The bis(trifluoromethoxy)biphenyl (6) was ground into a powder, and then vigorously stirred in 50 mL of acetic anhydride, and reacted at room temperature for 24 hours. After the reaction, the mixture was directly filtered, and the precipitate was collected and washed with water to neutral. After drying, 5.95 g of white solid (yield: 96%), 4,4'-diethylamino-2,2'-bis(trifluoro) Methoxy)biphenyl (7).

Determination of 4,4'-diamino-2,2'-acetyl-bis (trifluoromethoxy) biphenyl (7), melting point, nuclear magnetic resonance spectroscopy and hydrogen ^{(Proton nuclear magnetic resonance spectrum, 1} H NMR), Carbon-13 nuclear magnetic resonance spectrum ( ^13C NMR) and electron free mass spectrometry (EIMS) were used for analysis and identification. Mp: 268~269°C. ^{1 H NMR (600MHz, DMSO- d} 6, δ, ppm): 2.08 (s, 6H), 7.35 (d, J = 8.4Hz, 2H), 7.55 (dd, J 1 = 8.4Hz, J 2 = 1.9Hz , 2H), 7.90 (bs, 2H), 10.30 (s, 2H). ¹³ C NMR (150 MHz, DMSO- d ₆ , δ, ppm): 117.4, 119.1, 120.8, 122.5 (Quartet, *CF3), 24.0, 110.1, 117.2, 123.1, 132.1, 140.6, 145.8, 168.9. EIMS (m / z): Theory _{(C 18 H 14 F 6 N} 2 O 4) is 436.1; 436.1 analysis values.

6.95 g (15.93 mmol) of 4,4'-diethylamino-2,2'-bis(trifluoromethoxy)biphenyl (7) and 22 mL of 96% by weight sulfuric acid were added to a 100 mL three-necked round bottom. The flask was stirred until fully dissolved, then the temperature was lowered to 0 to 5 ° C for 30 minutes, and then 2 mL of 65% by weight of nitric acid was slowly dropped into the dosing funnel. After the completion of the addition, the reaction was carried out at 0 to 5 ° C for 2 hours, followed by the reaction at room temperature for 2 hours. After completion of the reaction, the solution was poured into ice water and stirred, and then the precipitate was collected and washed with water until neutral. After drying, 5.93 g of a yellow solid (yield: 71%), that is, 4,4'-diethylamino-2, 2'-bis(trifluoromethoxy)-5,5'-dinitrobiphenyl (8).

Determination of the melting point of 4,4'-diethylamino-2,2'-bis(trifluoromethoxy)-5,5'-dinitrobiphenyl (8) by hydrogen nuclear magnetic resonance spectroscopy (Proton nuclear The magnetic resonance spectrum, ¹ H NMR), carbon nuclear magnetic resonance spectrum ( ¹³ C NMR) and electron free mass spectrometry (EIMS) were analyzed and identified. Mp: 185~188 °C. ¹ H NMR (600 MHz, DMSO- d ₆ , δ, mp): 2.15 (s, 6H), 7.78 (s, 2H), 8.26 (s, 2H), 10.54 (s, 2H). ¹³ C NMR (150 MHz, DMSO- d ₆ , δ, ppm): 117.1, 118.8, 120.5, 122.2 (Quartet, *CF3), 23.7, 113.9, 122.0, 129.2, 133.8, 139.1, 148.4, 169.1. EIMS (m / z): Theory _{(C 18 H 12 F 6 N} 4 O 8) is 526.1; 526.1 analysis values.

5.93 g of (11.27 mmol) 4,4'-diethylguanidino-2,2'-bis(trifluoromethoxy)-5,5'-dinitrobiphenyl (8), 152 mL of water and 152 mL of 37% by weight hydrochloric acid was placed in a 500 mL three-necked round bottom flask, stirred uniformly with a magnet, and then the reaction temperature was raised to 110 ° C and reacted for 24 hours. After the reaction is completed, when the temperature of the solution is lowered to room temperature, the pH of the solution is adjusted to 10 with ammonia water, and then the precipitate is collected and washed with water until neutral, and after drying, 4.85 g of a yellow solid (yield: 97%) is obtained. 4,4'-Diamino-2,2'-bis(trifluoromethoxy)-5,5'-dinitrobiphenyl (9).

Determination of the melting point of 4,4'-diamino-2,2'-bis(trifluoromethoxy)-5,5'-dinitrobiphenyl (9) by hydrogen nuclear magnetic resonance spectroscopy (Proton nucleus magnetic resonance) Spectrum, ¹ H NMR), carbon-13 nuclear magnetic resonance spectrum ( ¹³ C NMR) and electron free mass spectrometry (EIMS) were analyzed and identified. Mp:>300 °C. ^{1 H NMR (600MHz, DMSO- d} 6, δ, ppm): 7.13 (s, 2H), 7.76 (s, 4H), 8.03 (s, 2H). ¹³ C NMR (150 MHz, DMSO- d ₆ , δ, ppm): 117.1, 118.8, 120.5, 122.2 (Quartet, *CF3), 107.1, 114.3, 128.3, 129.5, 147.0, 150.9. EIMS (m / z): Theory _{(C 14 H 8 F 6 N} 4 O 6) is 442.0; 442.0 analysis values.

2.00 g (5.23 mmol) of 4,4'-diamino-2,2'-bis(trifluoromethoxy)-5,5'-dinitrobiphenyl (9), 24 mL of ethyl acetate, 3.4 g of ammonium formate, 24 mL of ethanol, and 0.40 g of 10% by weight of Pd/C were sequentially added to a 100 mL Erlenmeyer flask, and the reaction was stirred with a magnet at room temperature for 24 hours. After completion of the reaction, the precipitate was removed by filtration through diatomaceous earth, and the filtrate was poured into a liquid separation bottle, washed with water until neutral, and the organic layer was collected, and then anhydrous sodium sulfate was added to remove water, and then the solvent was removed by a vacuum concentrator. Finally, ethyl acetate was used as the extract to purify by column chromatography. After drying, 0.85 g of skin color solid (yield: 49%), namely 4,4',5,5'-tetraamino-2, was obtained. 2'-bis(trifluoromethoxy)biphenyl (10).

Determination of the melting point of 4,4',5,5'-tetraamino-2,2'-bis(trifluoromethoxy)biphenyl (10) by hydrogen nuclear magnetic resonance spectroscopy (Proton nuclear magnetic resonance spectrum, ¹ H NMR), carbon nuclear magnetic resonance spectrum ( ^13C NMR), electron free mass spectrometry (EIMS), and elemental analysis were used for analysis and identification. Fig. 6 and Fig. 7 are hydrogen nuclear magnetic resonance spectra and mass spectra of 4,4',5,5'-tetraamino-2,2'-bis(trifluoromethoxy)biphenyl (10), respectively. Mp: 161~162 °C. ^{1 H NMR (600MHz, DMSO- d} 6, δ, ppm): 4.59 (s, 4H), 4.81 (s, 4H), 6.37 (s, 2H), 6.49 (s, 2H). ¹³ C NMR (150 MHz, DMSO- d ₆ , δ, ppm): 117.8, 119.5, 121.1, 122.8 (Quartet, *CF3), 105.9, 116.1, 118.6, 133.4, 135.1, 137.2. EIMS ( m/z ): Theory (C ₁₄ H ₁₂ F ₆ N ₄ O ₂ ) was 382.1; Elemental analysis: theoretical value (C ₁₄ H ₁₂ F ₆ N ₄ O ₂ ) is C, 43.99%; H, 3.16%; N, 14.66%. The analytical value is C, 44.38%; H, 3.30%; N: 14.50%.

Example 3: Preparation of 4,4',5,5'-tetraamino-2,2'-bis(trifluoromethyl)biphenyl (14)

30 mL of trifluoroacetic anhydride, 2.94 g (9.18 mmol) of 4,4'-diamino-2,2'-bis(trifluoromethyl)biphenyl (11) and 2.03 g of potassium nitrate were sequentially added to 100 mL. In a three-necked round bottom flask, the reaction was stirred with a magnet at 5 to 10 ° C for 3 days. After completion of the reaction, the solution was poured into ice water and stirred, and then the precipitate was collected and washed with water until neutral. After drying, 2.82 g of a brown solid (yield: 51%), that is, 4,4'-di-(trifluoroacetamidine). Amino)-2,2'-bis(trifluoromethyl)-5,5'-dinitrobiphenyl (12). The obtained preliminary product was directly subjected to the next reaction without purification.

Determination of the melting point of 4,4'-bis-(trifluoroacetamido)-2,2'-bis(trifluoromethyl)-5,5'-dinitrobiphenyl (12), and hydrogen nucleus Resonance magnetic resonance spectrum ( ¹ H NMR), carbon nuclear magnetic resonance spectrum ( ¹³ C NMR) and electron free mass spectrometry (EIMS) were used for analysis and identification. Mp: 234~238 °C. ^{1 H NMR (600MHz, DMSO- d} 6, δ, ppm): 8.23 (s, 2H), 8.40 (s, 2H), 12.10 (s, 2H). ¹³ C NMR (150 MHz, DMSO- d ₆ , δ, ppm): 112.6, 114.5, 116.4, 118.3 (Quartet, *CF3), 119.5, 121.4, 123.2, 125.0 (Quartet, *CF3), 131.4, 131.6, 131.8, 132.0 (Quartet, *C-CF ₃ ), 155.0, 155.2, 155.5, 155.7 (Quartet, *C-CF ₃ ), 125.8, 128.8, 129.1, 133.2, 144.6. EIMS ( m/z ): Theory (C ₁₈ H ₆ F ₁₂ N ₄ O ₆ ) was 602.0;

An aqueous solution of potassium carbonate (0.94 g of potassium carbonate in 13 mL of water), 5.00 g (8.30 mmol) of 4,4'-di-(trifluoroacetamido)-2,2'-bis(trifluoromethyl) The base 5,5'-dinitrobiphenyl (12) and 20 mL of methanol were sequentially added to a 100 mL three-necked round bottom flask, and the mixture was stirred at 80 ° C for 1 hour with a magnet. After the reaction was completed, the solution was poured into ice water and stirred, and then the precipitate was collected and washed with water until neutral, and the initial product was purified by column chromatography using dichloromethane as a solvent, and 0.4 g of an orange solid was obtained after drying. Yield: 12%), ie 4,4'-diamino-2,2'-bis(trifluoromethyl)-5,5'-dinitrobiphenyl (13).

Determination of the melting point of 4,4'-diamino-2,2'-bis(trifluoromethyl)-5,5'-dinitrobiphenyl (13) by hydrogen nuclear magnetic resonance spectroscopy (Proton nuclear magnetic resonance spectrum) , ¹ H NMR), carbon nuclear magnetic resonance spectrum ( ¹³ C NMR) and electron free mass spectrometry (EIMS) were analyzed and identified. Mp: 271~272 °C. ^{1 H NMR (600MHz, DMSO- d} 6, δ, ppm): 7.55 (s, 2H), 7.80 (s, 4H), 7.89 (s, 2H). ¹³ C NMR (150 MHz, DMSO- d ₆ , δ, ppm): 120.1, 121.9, 123.7, 125.5 (Quartet, *CF3), 133.6, 133.8, 134.0, 134.2 (Quartet, *C-CF ₃ ), 118.0, 119.8 , 129.5, 130.3, 145.1. EIMS ( m/z ): Theory (C ₁₄ H ₈ F ₆ N ₄ O ₄ ): 410.0;

1.85 g (4.51 mmol) of 4,4'-diamino-2,2'-bis(trifluoromethyl)-5,5'-dinitrobiphenyl (13), 24 mL of ethyl acetate, 3.4 G ammonium formate, 24 mL of ethanol, and 0.40 g of 10% by weight of Pd/C were sequentially added to a 100 mL Erlenmeyer flask, and stirred at a normal temperature for 24 hours with a magnet. After completion of the reaction, the precipitate was removed by filtration through diatomaceous earth, and the filtrate was poured into a liquid separation bottle, washed with water until neutral, and the organic layer was collected, and then anhydrous sodium sulfate was added to remove water, and then the solvent was removed by a vacuum concentrator. Finally, the column chromatography was carried out with n-hexane and ethyl acetate (1:3, by volume (v/v)) as the extract. After drying, 0.93 g of skin color solid (yield: 59%) was obtained. That is, 4,4',5,5'-tetraamino-2,2'-bis(trifluoromethyl)biphenyl (14).

The melting point of 4,4',5,5'-tetraamino-2,2'-bis(trifluoromethyl)biphenyl (14) was determined and subjected to hydrogen nuclear magnetic resonance spectroscopy (Proton nuclear magnetic resonance spectrum, ¹ H NMR). ), carbon nuclear magnetic resonance spectrum ( ¹³ C NMR), electron free mass spectrometry (EIMS) and elemental analysis were analyzed and identified. Fig. 8 and Fig. 9 are hydrogen nuclear magnetic resonance spectra and mass spectra of 4,4',5,5'-tetraamino-2,2'-bis(trifluoromethyl)biphenyl (14), respectively. Mp: spoiled at 173 °C. ^{1 H NMR (600MHz, DMSO- d} 6, δ, ppm): 4.75 (s, 4H), 5.02 (s, 4H), 6.28 (s, 2H), 6.78 (s, 2H). ¹³ C NMR (150 MHz, DMSO- d ₆ , δ, ppm): 122.6, 124.4, 126.2, 128.0 (Quartet, *CF3), 115.0, 115.2, 116.4, 115.6 (Quartet, *C-CF ₃ ), 110.8, 116.6 , 127.9, 133.1, 136.9. EIMS ( m/z ): Theory (C ₁₄ H ₁₂ F ₆ N ₄ ): 350.1; Elemental analysis: theoretical value (C ₁₄ H ₁₂ F ₆ N ₄ O ₂ ) is C, 48.01%; H, 3.45%; N, 16.00%. The analytical value is C, 48.99%; H, 3.58%; N, 15.79%.

Example 4: Preparation of polybenzimidazole (P1)

The apparatus was equipped with a 25 mL three-necked round bottom flask with nitrogen in/out and mechanical stirrer, 0.4101 g (1.69 mmol) of 4,4',5,5'-tetraamino-2,2'-dimethylbiphenyl ( 5) and 0.4370 g (1.69 mmol) of 4,4'-oxybis(benzoic acid) were added thereto and maintained under a nitrogen atmosphere for 30 minutes. Next, 9.7 mL (0.35 mmol/mL) of Eaton reagent was added and stirred at 80 to 100 ° C at 100 rpm until the monomer was completely dissolved. After the monomer is completely dissolved, the temperature is raised to 120 ° C for 1 hour, and then the temperature is raised to 145 ° C for 4 hours. After the reaction for 4 hours, the reaction solution will have a significant viscosity increase, and then the polymer solution is poured into water to form a filamentous precipitate. The precipitate was then collected and washed with water until neutral, and then extracted with ethanol for one day. Finally, it was vacuum dried at 200 ° C to obtain 0.7034 g of a polymer (yield: 97%), that is, polybenzimidazole (P1).

Example 5: Preparation of polybenzimidazole (P2)

The apparatus has a 25 mL three-necked round bottom flask with a nitrogen in/out and mechanical stirrer. 0.6807 g (1.78 mmol) of 4,4',5,5'-tetraamino-2,2'-bis(trifluoromethoxy) Biphenyl (10) and 0.4598 g (1.78 mmol) of 4,4'-diphenyl ether dicarboxylic acid were added thereto and maintained under a nitrogen atmosphere for 30 minutes. Then, 11.9 mL (0.30 mmol/mL) of Eaton reagent was added and stirred at 80 to 100 ° C at 100 rpm until the monomer was completely dissolved. After the monomer is completely dissolved, the temperature is raised to 120 ° C for 1 hour, and then the temperature is raised to 145 ° C for 7 hours. After the reaction for 7 hours, the reaction solution will have a significant viscosity increase, and then the polymer solution is poured into water to form a silky precipitate. Dian. The precipitate was then collected and washed with water until neutral, and then extracted with ethanol for one day. Finally, it was vacuum dried at 200 ° C to obtain 1.0021 g of a polymer (yield: 99%), that is, polybenzimidazole (P2).

Example 6: Preparation of polybenzimidazole (P3)

The apparatus has a 25 mL three-necked round bottom flask with a nitrogen in/out and mechanical stirrer, 0.6235 g (1.78 mmol) of 4,4',5,5'-tetraamino-2,2'-bis(trifluoromethyl) Biphenyl (14) and 0.4596 g (1.78 mmol) of 4,4'-diphenyl ether dicarboxylic acid were added thereto and maintained under a nitrogen atmosphere for 30 minutes. Then, 10.2 mL (0.35 mmol/mL) of Eaton reagent was added and stirred at 80 to 100 ° C at 100 rpm until the monomer was completely dissolved. After the monomer is completely dissolved, the temperature is raised to 120 ° C for 1 hour, and then the temperature is raised to 145 ° C for 19 hours, the reaction solution will have a significant viscosity increase, and then the polymer solution is poured into water to form a filamentous precipitate. The precipitate was then collected and washed with water until neutral, and then extracted with ethanol for one day. Finally, it was vacuum dried at 200 ° C to obtain 1.0216 g of a polymer (yield: 98%), that is, polybenzimidazole (P3).

Example 7: Preparation of polybenzimidazole (P4)

Polybenzimidazole (P4) was prepared in the same manner as in the preparation of polybenzimidazole (P1) except that the original tetraamine was replaced by 3,3',4,4'-tetraaminobiphenyl (TAB). The monomer is subjected to a polymerization reaction.

Example 8: Intrinsic viscosity of polybenzimidazoles (P1), (P2) and (P4) (η _Ing ^a And solubility test

The polybenzimidazole (P1), (P2) or (P4) was placed into a 0.20 g/dL polybenzimidazole/methanesulfonic acid solution, and the solution was measured at 35 ° C to obtain an intrinsic viscosity (η _inh ) . Solubility is determined by dissolving 30 mg of polybenzimidazole (P1), (P2) or (P4) in 1 mL of a stirred solvent and determining the degree of dissolution. The solvent includes N,N-dimethylacetamide (DMAc), N,N-dimethylformamide (DMF), N-methyl-2-pyrrolidone (NMP), dimethyl alum (DMSO), sulfuric acid (H ₂ SO ₄ ), or methanesulfonic acid (MSA). The test results are shown in Table 1 below.

In Table 1, the symbol "++" indicates that polybenzimidazole is soluble in a solvent at 80 ° C; the symbol "+" indicates that polybenzimidazole is soluble in a solvent at 100 ° C; the symbol "-" indicates polyphenylene. The imidazole is partially dissolved or insoluble in a solvent at 100 °C. As can be seen from Table 1, the polybenzimidazoles (P1) and (P2) disclosed herein have good solubility in a sulfuric acid or methanesulfonic acid solvent as compared with the polybenzimidazole (P4) as a comparative example. . In addition, polybenzimidazole (P2) is also soluble in solvents such as N,N-dimethylformamide or N-methyl-2-pyrrolidone, indicating that the polybenzimidazole disclosed herein does not Since the solubility is poor and precipitation or gelation occurs, it is suitable for coating into a film by a solution casting method.

Example 9: Thermal property test of polybenzimidazole (P1) and (P2)

The thermal properties of polybenzimidazole (P1) and (P2) were tested and the test results are shown in Table 2 below.

As can be seen from Table 2, the 5% pyrolysis temperature (T _d5% ) of polybenzimidazole (P1) and (P2) disclosed herein is 413 ° C and 516 ° C, and the 10% thermal cracking temperature (T _d10% ) is 467. At °C and 546 ° C, the glass transition temperature (T _g ) is greater than 370 ° C, indicating that the polybenzimidazole disclosed herein has good thermal stability.

Example 10-1: Preparation of proton exchange membrane

Dissolving polybenzimidazole (P1) and (P2) with N-methylpyrrolidone (NMP) as a solvent to prepare a polybenzimidazole solution having a concentration of 3 to 5% (weight/volume percentage (w/v)) . The polybenzimidazole solution was centrifuged at 6000 rpm for 1 hour using a centrifuge, and the upper clarified polybenzimidazole solution was collected. The polybenzimidazole solution was then cast on a glass plate and baked at 60 ° C for 6 hours. The film was immersed in water at 80 ° C for 2 hours, and finally the film was pressure-pressed in a vacuum oven at 200 ° C for 6 hours to obtain a flat polybenzimidazole film. Subsequently, the polybenzimidazole film was cut into an appropriate size, and vacuum-dried at 100 ° C to obtain a vacuum-dried polybenzimidazole film (P1) and a polybenzimidazole film (P2).

Example 10-2: Preparation of proton exchange membrane

Polybenzimidazole (P1) and (P2) are dissolved in methanesulfonic acid (MSA) as a solvent to prepare a concentration of 3 to 5% (weight/volume percentage (w/v)). Benzimidazole solution. At this time, a vacuum-dried polybenzimidazole film (P1) and a polybenzimidazole film (P2) were prepared in the same manner as in the above Example 10-1 except that a polybenzimidazole solution was cast in the glass. The plate was baked at 160 ° C for 12 hours.

Example 11: Oxidative stability test of polybenzimidazole film

First, an aqueous solution of 3% H ₂ O ₂ containing 4 ppm of Fe ^{2+ was} placed. After weighing the vacuum-dried polybenzimidazole film ( W _i ), the polybenzimidazole film was immersed in an aqueous H ₂ O ₂ solution and tested at 68 °C. The film was taken out every 24 hours, the film was washed several times with deionized water, vacuum dried, then the film weight ( W _f ), and calculated by W _loss = ( W _i - W _f ) / W _i × 100% The percentage of weight loss ( W _loss ). Repeat this process for more than 200 hours. The oxidation stability test results are shown in Fig. 10, and a conventional poly-2,2'-(m-phenyl)-5,5'-bibenzimidazole ( m- PBI) film was used as a comparative example.

As can be seen from Fig. 10, in the oxidative stability test, after 216 hours of testing, the polybenzimidazole film (P1), the polybenzimidazole film (P2), and the poly-2,2'-(m-phenyl)- The percentage _loss ( W _loss ) of the 5,5'-bibenzimidazole ( m- PBI) film was about 11%, about 6%, and about 22%, respectively, showing the polybenzimidazole film disclosed herein. P1) and polybenzimidazole film (P2) have good oxidative stability.

Example 12: Phosphoric acid doping process of polybenzimidazole film

The polybenzimidazole film cut into the appropriate size was vacuum dried at 100 ° C and weighed to dry film weight ( W _dry ). Next, the polybenzimidazole film was immersed in 75, 80, and 85% by weight phosphoric acid solution to saturation, and the film was taken out and weighed ( W _wet ). Phosphoric acid content (PA content) is defined as the percentage of doped phosphoric acid weight to dry film weight ( W _dry ). That is, the amount of phosphoric acid doping = ( W _wet - W _dry ) / W _dry × 100% . The phosphoric acid doping results of the polybenzimidazole film are shown in Fig. 11A and Fig. 11B, and Fig. 11A is a schematic diagram showing the relationship between the doping amount of phosphoric acid and the time of the polybenzimidazole film (P1); Fig. 11B is a polybenzoate. Schematic diagram of the phosphoric acid doping amount of the imidazole film (P2) versus time.

Example 13: Mechanical strength test of polybenzimidazole film

The polybenzimidazole film was cut into a size of 50 mm (length) x 5 mm (width) x 40 μm (thickness), using a universal testing machine (Testometric M500-25AT) at atmospheric pressure at 5 mm/min. The mechanical strength of the polybenzimidazole film was measured at a fixed tensile speed. The test environment is normal temperature and pressure, and the humidity is maintained at 50~60%. The undoped phosphoric acid film was tested after vacuum drying; the phosphoric acid doped film was immersed in the phosphoric acid solution before the test, and the film was taken out immediately before the test, and the excess phosphoric acid on the surface of the film was wiped clean. The results are shown in Table 3 below, and a poly-2,2'-(m-phenyl)-5,5'-bibenzimidazole ( m- PBI) film was used as a comparative example.

As is clear from Table 3, the polybenzimidazole film (P1) having a phosphoric acid doping amount of 204% by weight had a tensile strength of 24.4 MPa and a tensile strain of 143.3%. The polybenzimidazole film (P2) having a phosphoric acid doping amount of 142% by weight had a tensile strength of 17.0 MPa and a tensile strain of 33.3%. A poly-2,2'-(m-phenyl)-5,5'-bibenzimidazole ( m- PBI) film for use in a proton exchange membrane fuel cell is known in the art to have a phosphoric acid doping amount of 291% by weight. The tensile strength was 15.1 MPa and the tensile strain was 270.7%. The polybenzimidazole film (P1) and the polybenzimidazole film (P2) disclosed herein have excellent mechanical strength. “Tensile strength” in this specification refers to the maximum stress that a material can withstand before breaking. In this specification, "tensile strain" refers to the amount of deformation per unit volume of a material when it is subjected to a force.

Example 14: Proton conductivity test of polybenzimidazole film

The polybenzimidazole film is subjected to the aforementioned phosphoric acid doping process to prepare a phosphoric acid doped proton exchange membrane. The impedance of the film was measured using an electrochemical impedance spectroscopy (Princeton Applied Research VersaSTAT 3). First, the film is clamped in the jig, and the jig is placed in a temperature control tank, and the temperature is raised to 120 ° C for half an hour to remove water. Then, the temperature was further lowered to 60 ° C to measure the impedance, and then measured every 20 ° C, and finally the temperature was raised to 160 ° C. The frequency is 1 to 100 kHz, the voltage is 10 mV, and the proton conductivity is calculated by taking the measured impedance into σ(S/cm)=L(cm)/wtR(cm ² Ω). Where σ is the proton conductivity, L is the distance between the electrodes, w is the film width, t is the film thickness, and R is the measured impedance. In this test, the distance L between the electrodes was 1 cm, the film width was 1 cm, and the film thickness was 100 ± 10 μm. The results are shown in Tables 4 and 12 below, and a poly-2,2'-(m-phenyl)-5,5'-bibenzimidazole ( m- PBI) film was used as a comparative example.

It can be seen from Table 4 and Figure 12 that the polybenzimidazole film of the present invention is doped with phosphoric acid at different concentrations in a phosphoric acid solution at room temperature, and the doping amount of phosphoric acid (PA content, % by weight) is between 90 and 210. Between weight%. The polybenzimidazole film (P1) having a phosphoric acid doping amount of 204% by weight at 160 ° C had a proton conductivity of 4.72 × 10 ^-2 S/cm. The polybenzimidazole film (P2) having a phosphoric acid doping amount of 142% by weight at 160 ° C had a proton conductivity of 1.17 × 10 ^-2 S/cm.

Example 15-1: Single cell test

The catalyst and the polybenzimidazole solution were placed in a solvent of N,N-dimethylacetamide and stirred for 2 hours. The catalyst is Pt/C (40% Pt attached to carbon black, Johnson Matthey Company), and polybenzimidazole is the polybenzimidazole synthesized in this study. In the solution, the ratio of Pt/C, polybenzimidazole to N,N-dimethylacetamide is 20:1:150 (weight/weight/volume (μl)). The uniformly stirred solution was uniformly coated on a carbon cloth with a brush, and then the carbon was placed in an oven at 70 ° C for drying. The contents of Pt at the cathode and the anode were calculated to be about 0.8 mg/cm ² and 0.6 mg/cm ^{2 , respectively} . Finally, the electrode layer coated carbon cloth was immersed in 20% by weight of H ₃ PO ₄ for two days to complete the electrode fabrication. The cells are then stacked in the order of flow field plate/gasket/anode/proton exchange membrane/cathode/gasket/flow field plate. The membrane electrode assembly is stacked into a single cell without being hot pressed. The stacked cells are placed between the end plates, and the single cells are fixed by a pneumatic single cell fixture (ASCT-5, Asia Pacific Fuel Cell Technology Co., Ltd.). Next, a single cell test was conducted with a FCED-DD50 (Asia Pacific Fuel Cell Technology Co., Ltd.) test machine, hydrogen gas was introduced into the anode, and oxygen was introduced into the cathode. The gas flow rates of the anode and cathode were 0.2 L/min and 0.5 L/min, respectively, and the battery back pressure was 1 atm, the humidity was 0%, and the temperature was 160 °C. The polybenzimidazole film (P1) was used as a proton exchange membrane of the membrane electrode group for measurement. The fuel cell polarization curves of different phosphoric acid doping amounts and the fuel cell polarization curves of different film thicknesses were measured. The results are shown in Fig. 13A, Fig. 13B and Table 5 below.

Example 15-2: Single cell test

The cell test was carried out in the same manner as in the above Example 15-1 except that the polybenzimidazole film (P2) was used as the proton exchange membrane of the membrane electrode group. The fuel cell polarization curves of different phosphoric acid doping amounts and the fuel cell polarization curves of different film thicknesses were measured. The results are shown in Fig. 14A, Fig. 14B and Table 5 below.

It can be seen from Fig. 13A, Fig. 13B and Table 5 that when a polybenzimidazole film (P1) is used as the proton exchange membrane of the membrane electrode group, the polybenzimidazole film (P1) having a phosphoric acid doping amount of 160% by weight is A power density of 648 mW/cm ² at 160 ° C and a mold thickness of 50 μm; a polybenzimidazole film (P1) having a phosphoric acid doping amount of 204% by weight can reach 519 mW/cm ² at 160 ° C and a mold thickness of 50 μm. The power density; the polybenzimidazole film (P1) having a phosphoric acid doping amount of 204% by weight can reach a power density of 907 mW/cm ² at 160 ° C and a mold thickness of 60 μm.

From Fig. 14A, Fig. 14B and Table 5, when a polybenzimidazole film (P2) was used as the proton exchange membrane of the membrane electrode group, the polybenzimidazole film (P2) having a phosphoric acid doping amount of 101% by weight was A power density of 475 mW/cm ² at a mold thickness of 50 μm at 160 ° C; a polybenzimidazole film (P2) having a phosphoric acid doping amount of 142% by weight can reach 656 mW/cm ² at 160 ° C and a mold thickness of 60 μm. The power density; the polybenzimidazole film (P2) having a phosphoric acid doping amount of 142% by weight can reach a power density of 748 mW/cm ² at 160 ° C and a mold thickness of 40 μm.

Example 15-3: Single cell test

The single cell test was carried out in the same manner as in the above Example 15-1 except that a polybenzimidazole film (P1), a polybenzimidazole film (P2), and a poly-2,2'-(m-phenyl group) were used. The -5,5'-bibenzimidazole ( m- PBI) film was measured as a proton exchange membrane of the membrane electrode group. The fuel cell polarization curves were measured and the results are shown in Figure 15 and Table 6 below.

As can be seen from Fig. 15 and Table 6, the polybenzimidazole film (P1) having a phosphoric acid doping amount of 204% by weight had a power density of 907 mW/cm ² at 160 ° C and a mold thickness of 60 μm. The polybenzimidazole film (P2) having a phosphoric acid doping amount of 142% by weight reached a power density of 656 mW/cm ² at 160 ° C and a mold thickness of 60 μm. The poly-2,2'-(m-phenyl)-5,5'-bibenzimidazole ( m- PBI) film with a phosphoric acid doping amount of 291% by weight can reach 573 mW at 160 ° C and a mold thickness of 74 μm. The power density of cm ² .

As can be seen from the above-described inventive examples, the polybenzimidazole disclosed herein has good solubility, and thus the polybenzimidazole film made of polybenzimidazole has good oxidative stability.

It should be understood that the polybenzimidazole disclosed herein has good solubility and thus the polybenzimidazole film made of polybenzimidazole has good oxidative stability and is subjected to the R1 functional group of the tetraamine monomer. influences. As mentioned earlier, borrow R1 of the tetraamine monomer has a functional group having hydrophobic properties and a certain space barrier, thereby achieving certain technical effects of the present invention. Specifically, when R1 is a functional group having a certain space barrier, the polybenzimidazole obtained by the polymerization may cause a twisted structure of biphenyl in the polymer chain due to a functional group having a certain space barrier, thereby causing a molecular chain. It is not easy to stack and increase the solubility of polybenzimidazole during or after polymerization. Therefore, in the prior art, polybenzimidazole is solved in the process of polymerization because of poor solubility and precipitation or gelation problems. That is, the polybenzimidazole disclosed herein has a good solubility and can be easily coated into a film by a method such as solution casting.

On the other hand, when R1 is a functional group having a hydrophobic property, the above-mentioned polybenzimidazole film coated by a method such as solution casting may have a hydrophobic property. The use of this polybenzimidazole film as a proton exchange membrane for the membrane electrode assembly will help reduce the chance of H ₂ O ₂ diffusing onto the proton exchange membrane during fuel cell operation. Therefore, in the prior art, the problem that H ₂ O ₂ generates free radicals on the catalyst and attacks the polymer chain to degrade the polymer chain and promote the decrease in the strength of the proton exchange membrane is solved.

In summary, the polybenzimidazole disclosed herein has good solubility and improved applicability. Further, since the proton exchange membrane produced by the polybenzimidazole has high mechanical strength, thermal stability, oxidative stability, and proton conductivity, the fuel cell using the proton exchange membrane has good battery efficiency.

It is to be understood that the above-described embodiments are merely exemplary in nature and are not intended to limit the invention, and that the invention may be modified and modified without departing from the spirit and scope of the invention. Range when later The scope of the patent application is subject to the definition.

Claims (10)

a tetraamine compound represented by formula (I) or formula (II), Wherein R ₁ is a haloalkoxy group. The amine compound of claim 1, wherein R ₁ is -OC _n H _2n+1-m X _m ; X is halogen; n is an integer from 1 to 4; m is an integer from 1 to 2n+1. A method for producing a tetraamine compound, comprising the steps of: (a) reacting a compound represented by the formula (VI) with a deuteration reagent to form a compound represented by the formula (VII), Wherein R ₁ is a haloalkoxy group; R ₃ is an alkyl group or a haloalkyl group; (b) reacting a compound represented by the formula (VII) with a mononitrating reagent to form a compound represented by the formula (VIII), (c) subjecting a compound represented by the formula (VIII) to a desulfonation reaction to form a compound represented by the formula (IX), (d) subjecting a compound represented by the formula (IX) to a reduction reaction to form a tetraamine compound represented by the formula (I), A method for producing a tetraamine compound, comprising the steps of: (i) reacting a compound represented by the formula (VI) with a deuteration reagent and a mononitration reagent to form a compound represented by the formula (VIII), Wherein R ₁ is a haloalkoxy group; R ₃ is an alkyl group or a haloalkyl group; (ii) a compound represented by the formula (VIII) is subjected to a desulfonation reaction to form a compound represented by the formula (IX), (iii) subjecting a compound represented by the formula (IX) to a reduction reaction to form a tetraamine compound represented by the formula (I), A polybenzimidazole represented by formula (IV) or formula (V), Wherein R ₁ is a haloalkoxy group; R ₂ is a divalent linking group comprising an aryl group or a heteroaryl group; and n is an integer of 90 to 500. Polybenzimidazole according to claim 5, wherein R ₁ is -OC _n H _2n+1-m X _m ; X is halogen; n is an integer from 1 to 4; m is an integer from 1 to 2n+1 . Such as the polybenzimidazole of claim 5, wherein the R ₂ system The asterisk indicates the connection key. A method for producing polybenzimidazole, comprising the steps of: polymerizing a tetraamine monomer represented by the formula (I) with a diacid monomer represented by the formula (III) to form a poly group represented by the formula (IV) Benzimidazole; or The tetraamine monomer represented by the formula (II) is polymerized with the diacid monomer represented by the formula (III) to form a polybenzimidazole represented by the formula (V). Formula (II) Wherein R ₁ is a haloalkoxy group; R ₂ is a divalent linking group comprising an aryl group or a heteroaryl group; and n is an integer of 90 to 500. A proton exchange membrane comprising the polybenzimidazole of claim 5 of the patent application. A fuel cell comprising: an anode catalyst layer, a cathode catalyst layer, and a proton exchange membrane according to claim 9 wherein the proton exchange membrane is disposed on the anode catalyst layer and the cathode contact Between the media layers.