KR100744827B1 - New benzimidazole monomers terminated with trifluorovinyloxy groups and polybenzimidazoles membrane prepared by using the same monomers - Google Patents

Abstract

Provided are novel benzimidazole monomers containing trifluorovinyloxy groups with improved solubility against organic solvent and gas permeability, and reduced dielectric constant, while physical properties of polybenzimidazoles are preserved, and polybenzimidazoles membrane prepared by using the same monomers. The benzimidazole monomers containing trifluorovinyloxy groups represented by the formula(1), in which X is a direct bonding, are provided and prepared by reacting hydroxyl benzoate represented by the formula(2) with dibromotetrafluoroethane represented by the formula(3) in the presence of alkali metal or its precursor so as to prepare methyl(bromotetrafluoroethoxy)benzoate represented by the formula(4), reacting the methyl(bromotetrafluoroethoxy)benzoate represented by the formula(4) with amine compounds represented by the formula(5) to prepare imidazole benzoate compounds represented by the formula(6), and oxidizing the imidazole benzoate compounds represented by the formula(6).

Description

Fluorine-based benzimidazole monomers containing trifluorovinyloxy groups and methods for their preparation {New benzimidazole monomers terminated with trifluorovinyloxy groups and polybenzimidazoles membrane prepared by using the same monomers}

Figure 1 shows the hydrogen atom nuclear magnetic resonance spectrum ( ¹ H NMR) of the fluorine-based polybenzimidazole containing a perfluorocyclobutane group synthesized in Example 1 of the present invention.

Figure 2 shows the fluorine atom nuclear magnetic resonance analysis spectrum ( ¹⁹ F NMR) of the fluorine-based polybenzimidazole containing a perfluorocyclobutane group synthesized in Example 1 of the present invention.

Figure 3 shows the hydrogen atom nuclear magnetic resonance spectrum ( ¹ H NMR) of the fluorine-based polybenzimidazole containing a perfluorocyclobutane group synthesized in Example 2 of the present invention.

Figure 4 shows the fluorine atom nuclear magnetic resonance analysis spectrum ( ¹⁹ F NMR) of the fluorine-based polybenzimidazole containing a perfluorocyclobutane group synthesized in Example 2 of the present invention.

The present invention relates to a fluorinated benzimidazole monomer comprising a trifluorovinyloxy group and a polymer membrane using the same, and more particularly, to a novel fluorinated benzimidazole monomer prepared by introducing a trifluorovinyloxy group at both ends thereof. And a fluorinated benzimidazole polymer having a perfluorocyclobutane group by polymerizing the fluorinated benzimidazole monomer, and having a low surface energy perfluorocyclobutane group, while maintaining heat resistance, chemical resistance, etc. in a conventional organic solvent, The polymer membrane manufactured by using the same has improved the processability, gas permeability, adhesion, low surface energy, low dielectric constant, and the like, and is particularly useful in fuel cell, gas separation, optical, and electrical and electronic fields. Fluorinated benzimidazole monomers containing and high using the same Relates to a molecular membrane.

Polybenzimidazole has excellent properties such as thermal stability, mechanical properties, electrical insulation, chemical resistance, etc., so it can be used for aerospace, electronics, and membranes as intermediate insulation materials, high temperature gas separation, hemodialysis membranes, and fuel cell membranes. It is a polymer used.

However, these polymers do not dissolve well in general organic solvents compared to high heat resistance, and the glass transition temperature and the melting temperature are so high that there is a problem that pyrolysis occurs first during melting.

In addition, polybenzimidazole is not commercialized due to its excellent separation performance but low permeability when used in gas separation membranes, and polybenzimidazole has a high dielectric constant and shows disadvantages in microfabrication. In order to significantly lower the amount of fluorine is being introduced into these polymers.

Polybenzimidazole, which is mainly used in high temperature fuel cell membranes, does not dissolve in organic solvents when para-type monomers having the best physical properties are used. Therefore, there is a problem in mass production of thin films, which delays commercialization of fuel cell membranes. There was.

Therefore, many studies have been conducted to add fluorine groups to minimize the physical property degradation of the existing polybenzimidazole, to have sufficient solubility in organic solvents, to have a low dielectric constant, and to increase gas permeability.

Accordingly, the present inventors have tried to prepare a polybenzimidazole having improved solubility (organic solvent), low dielectric constant, gas permeability, and the like suitable for the fuel cell, gas separation, electric electronics, and optical fields.

As a result, fluorinated benzimidazole monomers prepared by introducing trifluorovinyloxy groups at both ends and polymers polymerized therein are conventionally resistant to contamination, water resistance, oil resistance, processability, solubility, low surface energy, It has been found that the low dielectric constant and the like have an improved effect, thus completing the present invention.

Accordingly, an object of the present invention is to provide a fluorinated benzimidazole monomer having improved various physical, electrical, optical, and transmissive properties and a polymer polymerized thereto.

Another object of the present invention is to provide a polymer membrane using the fluorinated benzimidazole monomer.

The present invention is characterized by a fluorinated benzimidazole monomer containing a trifluorovinyloxy group at both ends, as represented by the following formula (1).

는

또는

를 나타내고, X는 직접결합이거나, 또는 -O-, -S-, -CO-, -SO₂-, -SO- 또는 -C(CF₃)₂-를 나타낸다.In Chemical Formula 1,

Is

or

X is a direct bond or -O-, -S-, -CO-, -SO _2- , -SO- or -C (CF ₃ ) _2- .

In addition, the present invention has another feature in the method for producing a fluorine-based benzimidazole monomer containing a trifluorovinyloxy group at both terminals, as shown in the following Scheme 1, looking at this in more detail as follows: .

In one step, by reacting the hydroxy benzoate of Formula 2 with the dibromotetrafluoroethane of Formula 3 under water or an aprotic polar solvent, an alkaline earth metal or a precursor compound thereof, methyl (bromotetra) Fluoroethoxy) benzoate is prepared.

The water or aprotic polar solvent is used as a reaction solvent, among which the aprotic solvent is commonly used in the art specifically dimethyl sulfoxide (DMSO), N-methyl-2-pyrrolidone (NMP) , Dimethylformamide (DMF) and dimethylacetamide (DMAc) can be used.

The reaction solvent is preferably maintained in the concentration of 1 to 40% by weight of the total monomers of the reaction formulas (2) and (3), if the concentration is too thin, the reaction rate is slow, the efficiency is lowered, the concentration is 40% by weight When exceeded, the viscosity increases when substituted with sodium of Formula 2, which hinders the reaction.

In addition, an alkaline earth metal or a precursor compound thereof is used to induce a dehydrogenation reaction, and the alkaline earth metal or a precursor compound thereof may specifically use Na, NaH, NaOH, and KOH. When water is used as the reaction solvent, it is preferable to use NaOH and KOH. The alkaline earth metal or a precursor compound thereof is preferably used in a molar ratio of 1 to 2 with respect to Formula 2, and when the amount is less than 1 molar ratio, the reaction is not sufficiently performed and the earth metal which does not participate in the reaction when it exceeds 2 molar ratio. Or it is preferable to maintain the above range because it remains as an excess of the precursor compound thereof is not suitable for economics and reaction efficiency.

At this time, the reaction is preferably carried out for 1 to 48 hours in the temperature range of 0 to 50 ℃, if the reaction temperature is too low, the solvent is hardened and the reaction is not performed efficiently, if the temperature exceeds 50 ℃ There is a problem that temperature control is difficult due to exothermic reaction.

In step 2, the methyl (bromotetrafluoroethoxy) benzoate of Formula 4 is dissolved and reacted with an amine compound of Formula 5 to prepare an imidazole benzoate compound of Formula 6. The melting is carried out at a temperature at which Formulas 4 and 5 are soluble, specifically 150 to 250 ° C., and polyphosphoric acid is used for the melting.

In step 3, the fluoride benzimidazole monomer represented by the following Chemical Formula 1 is prepared by oxidizing the imidazole benzoate compound of Chemical Formula 6 under a highly polar organic solvent.

The organic solvent can be dissolved in the general formula (6), CH ₃ CN, di-glycol methyl ether (di-glycol methyl ether, diglyme), tetrahydrofuran (THF), dioxane and the like can be used. When the organic solvent is used in an amount of 5 to 40% by weight based on the total reactants, when the amount is less than 5% by weight, there is a problem that the reaction efficiency is lowered, and when the amount exceeds 40% by weight, the viscosity range is not suitable for performing the reaction. There is a problem indicating.

In addition, the oxidation reaction is carried out to induce a double bond of the imidazole benzoate compound of Formula 6, wherein the oxidation reaction generally maintains the conditions for the oxidation reaction in the art. Was carried out using.

The fluorine-based benzimidazole monomer prepared above is dissolved or melted in a solvent having a high boiling point to add heat in a range of 150 to 250 ° C. to prepare a fluorine-based polymer represented by the following Formula 7. At this time, almost all monomers without any side reaction forms the following polymer.

는

또는

를 나타내고, X는 직접결합이거나, 또는 -O-, -S-, -CO-, -SO₂-, -SO- 또는 -C(CF₃)₂-를 나타내며, n은 50 ∼ 1000을 나타낸다. In Chemical Formula 7,

Is

or

And X is a direct bond or -O-, -S-, -CO-, -SO _2- , -SO- or -C (CF ₃ ) _2- , n represents 50 to 1000.

The polymer prepared above has a perfluorocyclobutane group having excellent chemical resistance and thermal and thermal stability to polybenzimidazole used in the prior art, and thus has excellent pollution resistance, water resistance, oil resistance, processability, and solubility.

On the other hand, the present invention is another feature of the polymer film containing a fluorine-based polymer represented by the formula (7), the polymer film is made by performing a film production method generally used in the art, and is not particularly limited.

Looking at the method of producing a film using a fluorine-based polymer represented by the formula (7) in more detail.

First, a polymer solution is prepared by dissolving the polymer represented by Chemical Formula 7 in an organic solvent, and then coated on a surface of a support such as a porous polymer or a solid to form a film, and dried to form a polymer film. In this case, the coating is conventional, and specifically, bar coating, roll coating, flow coating, dip coating, comma coating, blade coating, die coating, or spin coating may be used.

The organic solvent does not induce a chemical reaction, specifically, for example, dimethyl sulfoxide (DMSO), dimethyl acetate (DMAc), dimethylformamide (DMF), N-methyl-2-pyrrolidone (NMP), and the like. Can be used. In addition, the support is generally used as a support for the membrane in the art, but is not particularly limited, and may be a glass plate, a metal, a ceramic, and a polymer of polysulfone or polyisamide.

The drying is carried out for 10 minutes to 24 hours under normal pressure or vacuum in the temperature range of 50 to 200 ℃, the drying conditions are typically carried out in the polymer film production process.

The polymer membrane prepared above may be prepared by applying any type of film, thin film, flat membrane, hollow fiber membrane, composite membrane, or tube membrane, and these may be used in all fields to which the membrane is applied, in particular, fuel cells, gas separation, optical and electric electronics. It can be used as a material, and is suitably used for pervaporation membrane, reverse osmosis membrane, gas separation membrane, fuel cell membrane and the like.

Hereinafter, the present invention will be described in more detail with reference to the following examples, which are not intended to limit the present invention.

Example 1

① Preparation of methyl 3- (2-bromotetrafluoroethoxy) benzoate

In a nitrogen atmosphere, 4.8 g (0.2 mol) of NaH was injected into 400 mL of dimethyl sulfoxide (DMSO), and then 30.4 g (0.2 mol) of methyl 3- (hydroxy) benzoate was slowly added thereto and stirred. After the hydrogen gas was generated, 52 g (0.2 mol) of dibromotetrafluoroethane was slowly injected to proceed with the reaction. At this time, an ice-water bath was used so that the reaction temperature did not exceed 30 ° C. during the entire reaction. After 16 hours, the reaction mixture was added to a separatory funnel, ethyl acetate was added, washed with water, water was removed with MgSO ₄ , and the solvent was dried under vacuum. The dried product was separated and purified through a column containing silica gel using ethyl acetate and hexane to obtain 43 g (0.13 mol) (yield 65%).

¹ H-NMR (CDCl ₃ , δ in ppm): 3.95 (s, 3H, OCH ₃ ), 7.42 to 8.01 (various m, 4H, CH arom.), ¹⁹ F-NMR (CDCl ₃ , δ in ppm): -86.52 (s, -CF ₂ CF ₂ Br), -68.64 (s, -CF ₂ CF ₂ Br).

② Preparation of 5,5'-bibenzimidazole-2,2'-di (methyl 3- (2-bromotetrafluoroethoxy) benzoate)

Under nitrogen atmosphere, 33.1 g (0.1 mol) of methyl 3- (2-bromotetrafluoroethoxy) benzoate and 9.6 g (45 mmol) of 3,3'-diaminobenzidine were added to 300 g of polyphosphoric acid, followed by a mechanical stirrer ( The reaction was carried out at 150 ℃ for 16 hours while stirring with a mechanical stirrer. After the reaction, the product was added dropwise to distilled water and stirred for one day. The precipitate obtained was filtered off and again immersed in a 10% aqueous solution of Na ₂ CO ₃ and stored for one day. After filtration again, the mixture was washed with distilled water several times and dried in vacuo. The dried product was separated and purified through a column containing silica gel using ethyl acetate and hexane to obtain 26.3 g (34 mmol) (yield 75%).

¹ H-NMR (DMSO, δ in ppm): 7.48-8.28 (various m, 14H, CH arom.), 13.22 (s, 2H, NH), ¹⁹ F-NMR (CDCl ₃ , δ in ppm): -84.89 (s, -CF ₂ CF ₂ Br), -69.76 (s, -CF ₂ CF ₂ Br).

③ Preparation of 5,5'-bibenzimidazole-2,2'-di (methyl 3- (trifluorovinyloxy) benzoate)

7.76 g (10 mmol), Zinc powder, 5,5'-bibenzimidazole-2,2'-di (methyl 3- (2-bromotedrafluoroethoxy) benzoate) under nitrogen atmosphere 1.44 g (22 mmol) was added to 30 mL of anhydrous di-glycol methyl ether (diglyme) and heated to 100 ° C. while stirring. After 16 hours the reaction was filtered through filter paper and the filtrate was dried in vacuo. The dried product was separated and purified through a column containing silica gel using ethyl acetate and hexane to obtain 3.92 g (6.8 mmol) (yield 68%).

¹ H-NMR (DMSO, δ in ppm): 7.53-8.46 (various m, 14H, CH arom.), 13.26 (s, 2H, NH), ¹⁹ F-NMR (DMSO, δ in ppm): -118.3 ( dd, cis -CF = CF ₂ ), -124.9 (dd, trans -CF = CCF ₂ ), -135.8 (dd, cis -CF = CCF ₂ ).

④ Production of polymer and film thereof using 5,5'-bibenzimidazole-2,2'-di (methyl 3- (trifluorovinyloxy) benzoate) as monomer

Under nitrogen atmosphere, 3.0 g of 5,5'-bibenzimidazole-2,2'-di (methyl 3- (trifluorovinyloxy) benzoate) was added to 10 mL of anhydrous diphenyl ether, followed by 48 at 220 ° C. Heated for hours. The reaction was added dropwise to excess methanol and stirred for one day. The obtained precipitate was filtered off, washed several times with methanol and dried in vacuo to obtain 2.5 g (yield 83%).

¹ H-NMR (DMSO, δ in ppm): 7.35 to 8.23 (various m, CH arom.), ¹⁹ F-NMR (DMSO, δ in ppm): -127.1 to -133.2. Intrinsic viscosity (Cannon-Fenske viscometer) 1.1 (g / dl) ^-1 .

The polymer obtained above was dissolved in 5% by weight in dimethyl acetate (DMAc), cast on a glass plate, dried for one day in an oven at 80 ° C., and vacuum dried for 10 hours in a 120 ° C. oven to prepare a polymer film.

Example 2

① methyl  4- (2- Bromotetrafluoroethoxy ) Benzoate  Produce

Methyl 3- (2-bromotetrafluoroethoxy) benzoate was prepared in the same manner as in Example 1, but prepared using methyl 4- (hydroxy) benzoate instead of methyl 3- (hydroxy) benzoate. (73% yield).

¹ H-NMR (CDCl ₃ , δ in ppm): 3.93 (s, 3H, OCH ₃ ), 7.28 to 8.11 (various m, 4H, CH arom.), ¹⁹ F-NMR (CDCl ₃ , δ in ppm): -86.48 (s, -CF ₂ CF ₂ Br), 68.62 (s, -CF ₂ CF ₂ Br).

② 5,5'- Bibenzimidazole -2,2'-D ( methyl  Preparation of 4- (2-bromotetrafluoroethoxy) benzoate)

5,5'-Benzizimidazole-2,2'-di (methyl 3- (2-bromotetrafluoroethoxy) benzoate) of Example 1, except that methyl 3- ( Prepared using methyl 4- (2-bromotetrafluoroethoxy) benzoate instead of 2-bromotetrafluoroethoxy) benzoate (yield 77%).

¹ H-NMR (DMSO, δ in ppm): 7.55-8.36 (various m, 14H, CH arom.), 13.13 (s, 2H, NH), ¹⁹ F-NMR (CDCl ₃ , δ in ppm): -84.79 (s, -CF ₂ CF ₂ Br), -69.71 (s, -CF ₂ F ₂ Br).

③ Preparation of 5,5'-bibenzimidazole-2,2'-di (methyl 4- (trifluorovinyloxy) benzoate)

5,5'-Benzenzimidazole-2,2'-di (methyl 3- (trifluorovinyloxy) benzoate) of Example 1, but was carried out in the same manner as 5,5'-Benzimide 5,5'-bibenzimidazole-2,2'-di (methyl 4- (2) instead of dazol-2,2'-di (methyl 3- (2-bromotetrafluoroethoxy) benzoate) -Bromotetrafluoroethoxy) benzoate) (yield 71%).

¹ H-NMR (DMSO, δ in ppm): 7.58-8.41 (various m, 14H, CH arom.), 13.26 (s, 2H, NH), 19F-NMR (DMSO, δ in ppm): -118.1 (dd , cis -CF = CF ₂ ), -124.6 (dd, trans -CF = CCF ₂ ), -135.4 (dd, cis -CCF = CCF ₂ ).

④ Production of polymer and film thereof using 5,5'-bibenzimidazole-2,2'-di (methyl 4- (trifluorovinyloxy) benzoate) as monomer

The same procedure as in Example 1, except that 5,5'-bibenzimidazole-2,2'-di (methyl 3- (trifluorovinyloxy) benzoate) was used. The polymer was prepared using dazol-2,2'-di (methyl 4- (trifluorovinyloxy) benzoate) (yield 85%).

¹ H-NMR (DMSO, δ in ppm): 7.32 to 8.26 (various m, CH arom.), ¹⁹ F-NMR (DMSO, δ in ppm): -127.2 to -130.4. Intrinsic viscosity (Cannon-Fenske viscometer) 1.4 (g / dl) ^-1 .

Comparative example

In a nitrogen atmosphere, 5 g (0.0257 mol) of dimethyl isophthalate and 5.507 g (0.0257 mol) of 3,3'-diaminobenzidine were added to 100 g of polyphosphoric acid, followed by stirring with a mechanical stirrer for 16 hours at 190 ° C. Reaction. After the reaction, the product was added dropwise to distilled water and stirred for one day. The precipitate obtained was filtered off and again immersed in saturated aqueous NaHCO ₃ solution and stored for one day. After filtration, the mixture was washed several times with distilled water and methanol and dried in vacuo. At this time, the intrinsic viscosity (Cannon-Fenske viscometer) 1.3 (g / dl) ^-1 .

The polymer thus obtained was dissolved in 5% by weight in dimethyl acetate (DMAc), cast on a glass plate, dried for one day in an oven at 80 ° C., and vacuum dried for 10 hours in a 120 ° C. oven to prepare a polymer film.

Experimental Example 1

Solubility experiments were performed using the polymer films prepared in Examples 1 and 2 and Comparative Examples, and the results are shown in Table 1 below.

[How to measure]

Each film was immersed in a solution of excess dimethyl acetate (DMAc), dimethylformamide (DMF), N-methyl-2-pyrrolidone (NMP), sulfuric acid (H ₂ SO ₄ ) and stirred at room temperature for one day. Subject solubility was measured.

division Dimethyl Acetate (DMAc) Dimethylformamide (DMF) N-methyl-2-pyrrolidone (NMP) Sulfuric acid (H ₂ SO ₄ ) Example 1 s s s s Example 2 s s s s Comparative example s sw sw s s: recording well sw: swelling without melting

As shown in Table 1, it was confirmed that the polymers of Examples 1 and 2 were superior in solubility in various solvents as compared to the polymers of the Comparative Examples.

Experimental Example 2

Glass transition temperatures were measured using the polymer films prepared in Examples 1 and 2 and Comparative Examples, and the results are shown in Table 2 below.

[How to measure]

Using each film, the temperature was measured up to 500 ° C. under a nitrogen atmosphere at 10 ° C./min using a DSC.

division Glass transition temperature (℃) Example 1 247 Example 2 279 Comparative example 430

As shown in Table 2, it was confirmed that the polymers of Examples 1 and 2 had a lower glass transition temperature than the polymers of the Comparative Examples, thereby improving meltability and processability.

Experimental Example 3

Ultimate elongation was measured using the polymer films prepared in Examples 1 and 2 and Comparative Examples, and the results are shown in Table 3 below.

division Film thickness (㎛) Tensile Elongation at break (%) Example 1 50 305 Example 2 45 279 Comparative example 60 245

As shown in Table 3, it was confirmed that the polymers of Examples 1 and 2 were improved in physical properties of extreme elongation while the film thickness was thinner than the polymers of the Comparative Examples.

As described above, the polymer membrane containing the fluorinated benzimidazole monomer according to the present invention maintains the strength of the existing polymer as well as the processability and various solvents due to the introduction of trifluorovinyloxy groups at both ends of the flexible chain. Its solubility is improved, so that it can be suitably applied to polymer films in various forms.

Claims (10)

As represented by the following Chemical Formula 1, a fluorine benzimidazole monomer containing a trifluorovinyloxy group at both ends thereof:  [Formula 1]

In Chemical Formula 1,

Is

In this case, X represents a direct bond. Under an alkali metal or a precursor compound thereof, hydroxy benzoate of the following formula (2) is reacted with dibromotetrafluoroethane of the following formula (3) to prepare methyl (bromotetrafluoroethoxy) benzoate of the following formula (4). 1 step to do, A second step of preparing an imidazole benzoate compound of formula 6 by reacting methyl (bromotetrafluoroethoxy) benzoate of formula 4 with an amine compound of formula 5 Next, three steps of preparing a fluorine benzimidazole monomer represented by the following Chemical Formula 1 by oxidizing the imidazole benzoate compound of Chemical Formula 6 Method for producing a fluorinated benzimidazole monomer, characterized in that consisting of:

In Chemical Formula 1,

Is

In this case, X represents a direct bond. The aprotic polar solvent of claim 2 wherein the one-step reaction is selected from dimethyl sulfoxide (DMSO), N-methyl-2-pyrrolidone (NMP), dimethylformamide (DMF) and dimethylacetamide (DMAc). Method for producing a fluorinated benzimidazole monomer, characterized in that carried out under. The method of claim 2, wherein the alkali metal or a precursor compound thereof is selected from Na, NaH, NaOH, and KOH. The method of claim 2, wherein the polyfluoric acid is used in the two-step reaction. The method of claim 2, wherein the three-stage oxidation reaction uses zinc. delete delete delete delete

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