CN100336843C - Sulfonated high polymer containing bisphenol fluorine, synthesis and application thereof - Google Patents

Abstract

The present invention relates to a sulfonated superpolymer containing bisphenol fluorene, synthesis thereof and application thereof. The structure of the compound is shown in type (I), and the compound has the synthetic processes that a bisphenol fluorene monomer, a sulfonated dihalo monomer and a dihalo monomer carry out copolymerization under the function of potassium carbonate in a polar aprotic solvent, and the sulfonated superpolymer having different degrees of sulphonation and containing the bisphenol fluorene is prepared by adjusting the molar ratio of the sulfonated dihalo monomer to the dihalo monomer. A proton exchange membrane prepared by the superpolymer has the advantages of low cost, high stability, high mechanical strength, good water absorbability, large proton exchange capacity, etc., and has latent application value in the field of fuel cells.

Description

Sulfonated polymer containing bisphenol fluorene and its synthesis and application

technical field

The invention relates to a kind of sulfonated high polymer containing bisphenol fluorene and its synthesis and application.

technical background

At present, energy and environmental issues are one of the focuses of the world. Since the middle of the 20th century, with the advancement of science and technology, the process of industrialization has accelerated, and the consumption of conventional energy has continued to accelerate. Due to the burning of conventional energy sources such as oil, natural gas, and coal, a large amount of harmful gases are released, such as carbon monoxide, carbon dioxide, sulfide, nitrogen oxides, etc., leading to the deterioration of the global environment. The greenhouse effect, damage to the ozone layer, and abnormal climate have affected people's lives. In all aspects, some areas were also attacked by acid rain and photochemical smog.

Energy and environmental crisis are problems that must be overcome for sustainable development. Scientists from all over the world are committed to finding new ways to use energy efficiently to improve energy efficiency while reducing environmental pollution. Fuel cells are currently recognized as the preferred method to solve this problem at the same time. Since the fuel cell directly converts chemical energy into electrical energy without going through a heat engine process and is not limited by the Carnot cycle, its efficiency is much higher than that of ordinary internal combustion engines and steam engines. Fuel cells are also a clean way to utilize energy. Taking hydrogen fuel cells as an example, the product is water, which is environmentally friendly.

Proton exchange membrane fuel cell (PEMFC) is the fifth-generation fuel cell. In addition to the advantages of general fuel cells, it also has the advantages of rapid start-up at room temperature, no electrolyte loss, easy discharge of water, long life, specific power and specific energy. Advanced outstanding features. The United States, Japan, Germany, Canada and other countries and their major companies have spent huge sums of money in researching PEMFC, using it as a vehicle power source in the 21st century. Some people estimate that fuel cell vehicles will become popular in 2020.

Proton Exchange Membrane (PEM) is one of the key materials of PEMFC, and the performance of PEM directly affects the overall performance of the fuel cell. At present, the PEM widely used in the world is DuPont's Nafion membrane, which is a perfluorosulfonic acid proton exchange membrane with the following structural formula:

where x=6-10; y, z=1

Nafion membrane has the advantages of stable chemical properties, thermal stability, high mechanical strength, and high proton conductivity. Under the condition of saturated water absorption, the proton conductivity reaches 10 ^-2 -10 ^-1 Scm ^-1 . It can work continuously for tens of thousands of hours at 80°C. However, Nafion membrane has disadvantages such as complex synthesis route, high preparation cost, low alcohol resistance coefficient, and sharp drop in proton conductivity due to water loss when the temperature is higher than 100 °C. Now, R&D personnel from all over the world are devoting themselves to looking for better performance Nafion membrane substitutes. The new PEM must meet the following requirements: (1) low production cost; (2) maintain good proton conductivity at high temperature (greater than 100°C) and low temperature (less than 0°C); (3) good mechanical properties

Contents of the invention

The object of the present invention is to provide a class of sulfonated high polymers containing bisphenol fluorene that can be used to prepare fuel cell PEMs at low cost and a preparation method thereof, as well as the application of such high polymers in the preparation of PEMs (especially fuel cell PEMs) .

The invention also provides a kind of PEM preparation method with high product yield, simple process and economy.

The structure of the sulfonated polymer containing bisbisphenol fluorene of the present invention is shown in formula (1):

In formula (I): m+n=10-100; R=H or CH ₃ ;

The synthetic route of the sulfonated high polymer containing bisphenol fluorene of the present invention is as follows:

The structure of the bisphenol fluorene monomer 2 adopted is shown in formula (II):

R=H or _CH3

2a 2b

(II)

The structures of the sulfonated dihalogenated monomer 3 and dihalogenated monomer 4 used are shown in formula (III):

3B: X=-SO ₂ -, Y=F; 4B: X=-SO ₂ -, Y=F;

3C: X=-SO ₂ -, Y=Cl) 4C: X=-SO ₂ -, Y=Cl)

(III)

The reaction formula of synthesizing the sulfonated high polymer containing bisphenol fluorene is shown in formula (IV):

The different sulfonated polymers containing bisphenol fluorene shown in formula (IV) are distinguished by the symbol "1R3 _x ", and R is used to distinguish whether the bisphenol fluorene monomer used is 2a or 2b, and 3 represents different sulfonate Dihalogenated monomer 3A, 3B or 3C, the subscript x represents the ratio of the amount of sulfonated dihalogenated monomer to the sum of the amount of sulfonated dihalogenated monomer and dihalogenated monomer, expressed as a percentage. For example: polymer 1aA ₈₀ means that monomer 2a and monomer 3A and 4A are copolymerized, wherein the amount of 3A material accounts for 80% of the sum of the amount of 3A and 4A material; polymer 1aB ₄₀ means that monomer 2a and monomer Synthesis of monomer 3B and copolymerization of monomer 4B, wherein the amount of the substance of 3B accounts for 40% of the sum of the amounts of the substances of 3B and 4B. Polymer 1bC ₆₀ means synthesized by monomer 2b and monomer 3C and monomer 4C, wherein the amount of 3C accounts for 60% of the sum of the amounts of 3C and 4C.

The synthesis of the bisphenol fluorene-containing sulfonated high polymer 1R3 _x of the present invention can adopt the conventional method for preparing polyarylether. The specific steps are:

As shown in formula (IV), reactant 2, 3, 4 and dehydrating agent potassium carbonate, toluene and reaction solvent are added in the reaction vessel, the amount of substance of reactant 2 is equal to the sum of the amount of substance of reactant 3 and 4 , the amount of potassium carbonate is 1.1-1.5 times that of reactant 2, and the amount of toluene in milliliters is 5-6 times that of 2 mmoles of reactant; the reaction solvent is a polar aprotic solvent such as N, N-dimethyl Acetamide (DMAc), dimethyl sulfoxide (DMSO), N, N-dimethylformamide (DMF) or N-methylpyrrolidone (NMP), etc., the solvent volume (in milliliters) is reactant 2 (in millimoles) 3-4 times; the whole reaction is carried out under the protection of nitrogen, electromagnetic stirring, first reacted at 140-155 ℃ for 2-3 hours, the water generated by the reaction process is taken out by toluene, and then continue to heat up to 165-180°C for 18-21 hours. The reaction solution is precipitated in methanol aqueous solution, filtered, and the collected product is dried in a vacuum oven at 80-110° C. for 24-48 hours to obtain the desired sulfonated polymer containing bisphenol fluorene.

The sulfonated high polymer containing bisphenol fluorene of the invention can be used to prepare a proton exchange membrane (PEM), and the obtained PEM is suitable for being used as a fuel cell proton exchange membrane.

The method for preparing a proton exchange membrane with the sulfonated polymer containing bisphenol fluorene of the present invention is: dissolving the sulfonated polymer containing bisphenol fluorene in a polar aprotic solvent DMAc, DMF, DMSO or NMP In this method, the proton exchange membrane material is prepared by volatilizing the solvent in a dust-free environment at 55-80°C by the solution coating method. The specific steps are: dissolve the sulfonated polymer containing bisphenol fluorene in polar aprotic solvents such as DMAc, DMSO, DMF or NMP, etc., precipitate in 8-10wt% hydrochloric acid aqueous solution, and keep at 60-80°C After 6-8 hours, the polymer after acidification is removed by dialysis to remove inorganic salts; filtered, washed three times, and vacuum-dried at 80°C for 24-48 hours; Proton exchange membrane (PEM) is obtained by volatilizing the solvent at 55-80°C (optimally 60°C) under dust-free conditions.

The invention synthesizes a class of low-cost sulfonic acid type bisphenol fluorene-containing sulfonated polymers that can be used to prepare proton exchange membranes. A kind of sulfonated polymer containing bisphenol fluorene was synthesized by copolymerization reaction of bisphenol fluorene monomer 2, dihalogen monomer 3 and dihalogen monomer 4 containing bissulfonic acid sodium group in polar aprotic solvent . This kind of high polymer is precipitated, purified, acidified, dissolved to form a membrane, and a new type of fluorine-free PEM with excellent comprehensive performance is obtained. This type of PEM material has the following characteristics:

1. Utilizing cheap and easy-to-obtain chemical raw materials and adopting a conventional route for preparing polyarylether, which is simple and easy, and solves the cost problem of materials.

2. As a functional polymer material, polyarylether has excellent chemical, physical and mechanical properties such as high temperature resistance, creep resistance, high strength, and toughness. It has been widely used in the electronics industry, aerospace equipment, and military engineering. The sulfonated high polymer containing bisphenol fluorene synthesized by the invention has a polyarylether skeleton and can meet the requirements of PEMFC on the physical, chemical and mechanical properties of PEM.

3. The general method for preparing sulfonated polyarylether materials is to prepare polyarylether polymer compounds first, and then sulfonate them. The sulfonic acid group attacks the aromatic ring with higher electron density, so the reversible desulfonation reaction is easier to occur. The invention directly uses the sulfonated monomer, the sulfonic acid group is connected to the less active aromatic ring, and the chemical property of the polymer is more stable.

4. The sulfonic acid group of the sulfonated polymer containing bisphenol fluorene prepared by the present invention is connected on the benzene ring with an electron-withdrawing group, which is conducive to improving the acidity of the sulfonic acid group and making the protons of the polymer Enhanced conductivity.

5. The sulfonated high polymer containing bisphenol fluorene synthesized by the present invention can obtain different water absorption, proton Conductivity of sulfonated polymers that meet different conditions of use.

Detailed ways:

One, the embodiment of synthesizing the sulfonated high polymer containing bisphenol fluorene

Embodiment 1-1, the synthesis of polymer 1RA ₁₀₀ :

Put 0.7008g (2mmol) bisphenol fluorene monomer 2a, 0.8466g (2mmol) sulfonated dihalogen monomer 3A, 0.3455g (2.5mmol) anhydrous potassium carbonate, 8mL DMSO and 10mL toluene into a three-necked flask, nitrogen protection Then, heat up to 150°C, keep it under magnetic stirring for 2 hours, use toluene to take out the water produced, then raise the temperature to 175°C, react for 20 hours, cool, and pour the reactant into 100mL of methanol with a volume ratio of 8:2 under constant stirring mixed solution with water, filtered, washed three times with distilled water, and dried under vacuum at 80°C for 24 hours to obtain 1.3037 g of sodium sulfonated polymer 1RA ₁₀₀ with a yield of 89%.

Embodiment 1-2, the synthesis of polymer 1RA ₈₀ :

With 0.7008g (2mmol) bisphenol fluorene monomer 2a, 0.6757g (1.6mmol) sulfonated dihalogen monomer 3A, 0.0873g (0.4mmol) dihalogen monomer 4A, 0.3455g (2.5mmol) anhydrous potassium carbonate, Add 8mL DMSO and 10mL toluene into a three-necked flask, under the protection of nitrogen, raise the temperature to 150°C, keep it under magnetic stirring for 2 hours, use toluene to take out the generated water, then raise the temperature to 175°C, react for 20 hours, cool down, and keep stirring The reactant was poured into 100 mL methanol-water mixed solution with a volume ratio of 8:2, filtered, washed three times with distilled water, and vacuum-dried at 80°C for 24 hours to obtain 1.3045 g of sodium sulfonated polymer 1RA ₈₀ , with a yield of 94%.

Embodiment 1-3, the synthesis of polymer 1RA ₆₀ :

With 0.7008g (2mmol) bisphenol fluorene monomer 2a, 0.5068g (1.2mmol) sulfonated dihalogen monomer 3A, 0.1746g (0.8mmol) dihalogen monomer 4A, 0.3455g (2.5mmol) anhydrous potassium carbonate, Add 7mL DMSO and 10mL toluene into a three-necked flask, under the protection of nitrogen, raise the temperature to 150°C, keep it under magnetic stirring for 3 hours, use toluene to take out the generated water, then raise the temperature to 175°C, react for 20 hours, cool, and keep stirring The reactant was poured into 100 mL methanol-water mixed solution with a volume ratio of 1:1, filtered, washed three times with distilled water, and vacuum-dried at 80°C for 24 hours to obtain 1.2185 g of sodium sulfonated polymer 1RA ₆₀ , with a yield of 94%.

Embodiment 1-4, the synthesis of polymer 1RA ₅₀ :

0.7008g (2mmol) bisphenol fluorene monomer 2a, 0.4223g (1mmol) sulfonated dihalogen monomer 3A, 0.2182g (1mmol) dihalogen monomer 4A, 0.3455g (2.5mmol) anhydrous potassium carbonate, 7mL DMSO and 10mL of toluene, put into a three-necked flask, under the protection of nitrogen, raise the temperature to 150°C, keep it under magnetic stirring for 3 hours, use the toluene to take out the generated water, then raise the temperature to 175°C, react for 20 hours, cool, and stir the reaction continuously The mixture was poured into 100 mL of methanol-water mixed solution with a volume ratio of 1:1, filtered, washed three times with distilled water, and vacuum-dried at 80°C for 24 hours to obtain 1.2310 g of sodium sulfonated polymer 1RA ₅₀ with a yield of 98%.

Embodiment 1-5, the synthesis of polymer 1RA ₄₀ :

With 0.7008g (2mmol) bisphenol fluorene monomer 2a, 0.3378g (0.8mmol) sulfonated dihalogen monomer 3A, 0.2618g (1.2mmol) dihalogen monomer 4A, 0.3455g (2.5mmol) anhydrous potassium carbonate, Add 6mL DMSO and 10mL toluene into a three-necked flask, under the protection of nitrogen, heat up to 150°C, keep it under magnetic stirring for 2 hours, use toluene to take out the generated water, then heat up to 175°C, react for 20 hours, cool, and keep stirring The reactant was poured into 100 mL methanol-water mixed solution with a volume ratio of 1:1, filtered, washed three times with distilled water, and vacuum-dried at 80°C for 24 hours to obtain 1.2154 g of sodium-form sulfonated polymer 1RA ₄₀ with a yield of 100%.

Embodiment 1-6, the synthesis of polymer 1RA ₂₀ :

With 0.7008g (2mmol) bisphenol fluorene monomer 2a, 0.1689g (0.4mmol) sulfonated dihalogen monomer 3A, 0.3491g (1.6mmol) dihalogen monomer 4A, 0.3455g (2.5mmol) anhydrous potassium carbonate, Add 6mL DMSO and 10mL toluene into a three-necked flask, under the protection of nitrogen, heat up to 150°C, keep it under magnetic stirring for 3 hours, use toluene to take out the generated water, then heat up to 175°C, react for 20 hours, cool, and keep stirring The reactant was poured into 100 mL methanol-water mixed solution with a volume ratio of 1:1, filtered, washed three times with distilled water, and vacuum-dried at 80°C for 24 hours to obtain 1.1036 g of sodium sulfonated polymer 1RA ₂₀ with a yield of 97%.

Two, the embodiment of preparing PEM

Example 2-1, preparation of proton exchange membrane by polymer 1RA ₁₀₀

Dissolve the sodium-type sulfonated polymer 1RA ₁₀₀ synthesized as in Example 1-1 in DMAc to form a solution with a concentration of 10%, precipitate it in 80 mL of 10% hydrochloric acid aqueous solution, keep it at 60°C for 6 hours, and acidify The final polymer is removed by dialysis to obtain the sulfonic acid polymer. Filter, wash with water three times, and dry under vacuum at 80°C for 48 hours. The obtained sulfonic acid polymer was re-dissolved with DMAc, prepared into a solution with a concentration of 10%, poured into a flat and clean glass dish and volatilized the solvent at 60°C under dust-free conditions to form a film. In order to completely remove the solvent, the obtained film was heated at 110°C Vacuum dry for 24 hours.

Example 2-2, preparation of proton exchange membrane by polymer 1RA ₈₀

The polymer 1RA ₁₀₀ in Example 2-1 was replaced with polymer 1RA ₈₀ , and the preparation method was the same as in Example 2-1.

Embodiment 2-3, prepare proton exchange membrane by polymer 1RA ₆₀

The polymer 1RA ₁₀₀ in Example 2-1 was replaced with polymer 1RA ₆₀ , and the preparation method was the same as in Example 2-1.

Embodiment 2-4, prepare proton exchange membrane by polymer 1RA ₅₀

The polymer 1RA ₁₀₀ in Example 2-1 was replaced with polymer 1RA ₅₀ , and the preparation method was the same as in Example 2-1.

Embodiment 2-5, prepare proton exchange membrane by polymer 1RA ₄₀

The polymer 1RA ₁₀₀ in Example 2-1 was replaced with polymer 1RA ₄₀ , and the preparation method was the same as in Example 2-1.

Embodiment 2-6, prepare proton exchange membrane by polymer 1RA ₂₀

The polymer 1RA ₁₀₀ in Example 2-1 was replaced with polymer 1RA ₂₀ , and the preparation method was the same as in Example 2-1.

Claims (4)

1. a class formation is suc as formula the preparation method of the sulfonated high polymer that contains bisphenol fluorene shown in (I),

In the formula (1): m+n=10-100; R=H or CH ₃

Its concrete steps are: reactant 2,3,4 and dewatering agent salt of wormwood, toluene and reaction solvent are added in the reaction vessel, the amount of substance of reactant 2 equals the amount of substance sum of reactant 3 and 4, the amount of substance of salt of wormwood is 1.1-1.5 a times of reactant 2, and the toluene consumption is 5-6 times of reactant 2 mmole numbers in milliliter; Reaction solvent is a polar aprotic solvent, and solvent volume is that unit is 3-4 a times of reactant 2 mmole numbers with the milliliter; Entire reaction is carried out under nitrogen protection, and induction stirring 140-155 ℃ of reaction 2-3 hour, is taken the water that reaction process generates out of by toluene earlier, continues to be warmed up to 165-180 ℃ then and keeps 18-21 hour; Reaction solution precipitates in methanol aqueous solution, filters, and collects product in 80-110 ℃ of vacuum-drying 24-48 hour, promptly obtains the required sulfonated high polymer that contains bisphenol fluorene:

Described reactant 2 is the bisphenol fluorene monomer, and its structure is suc as formula shown in (II):

R=H or CH ₃

2a 2b

(II) ：

Described reactant 3 and 4 is respectively sulfonation dihalo-monomer and dihalo-monomer, and its structure is suc as formula shown in (III):

2. method according to claim 1 is characterized in that described polar aprotic solvent is a N,N-dimethylacetamide, N, dinethylformamide, methyl-sulphoxide or N-Methyl pyrrolidone.

3. the application of the sulfonated high polymer that contains bisphenol fluorene that claim 1 makes in the preparation proton exchange membrane, it is characterized in that the described sulfonated high polymer that contains bisphenol fluorene is dissolved in polar aprotic solvent N, the N-N,N-DIMETHYLACETAMIDE, N, dinethylformamide, in methyl-sulphoxide or the N-Methyl pyrrolidone, use the solution coating method, solvent flashing makes proton exchange membrane material under 55-80 ℃ of dustfree environment.

4. application according to claim 3 is characterized in that the proton exchange membrane material of described proton exchange membrane as fuel cell.