CN109821426B

CN109821426B - A kind of preparation method and use of polyimide film containing binaphthalene structure

Info

Publication number: CN109821426B
Application number: CN201910056350.2A
Authority: CN
Inventors: 邓国雄; 王一雷; 薛松
Original assignee: Tianjin University of Technology
Current assignee: Tianjin University of Technology
Priority date: 2019-01-22
Filing date: 2019-01-22
Publication date: 2021-08-03
Anticipated expiration: 2039-01-22
Also published as: CN109821426A

Abstract

The invention discloses a preparation method and application of a polyimide film containing a binaphthalene structure, which is used for the separation of O ₂ /N ₂ and CO ₂ /N ₂ . The polyimide separation membrane uses binaphthylamine monomers with different pendant functional groups and dianhydrides to synthesize polyimide resin films. The polyimide resin films have the characteristics of high gas permeability and high selectivity: at 0.8 Under the working pressure of MPa, the permeability coefficient of O ₂ exceeds 300 barrer, and the permeability efficiency of CO ₂ exceeds 800 barrer; the permeability coefficient of nitrogen gas is less than 25 barrer; the selectivity coefficient of O ₂ /N ₂ exceeds 13, and the permeability coefficient of CO ₂ The selectivity coefficient of /N ₂ exceeds 68. The polyimide film exhibits excellent heat resistance (over 500°C) and mechanical properties.

Description

Preparation method and application of polyimide film containing binaphthyl structure

Technical Field

The invention belongs to the technical field of chemical industry, and designs a preparation method and application of a polyimide gas separation film with high temperature resistance and organic solvent resistance, wherein the prepared gas separation film is suitable for CO in industrial waste gas₂Recovery of gases, combustion-supporting combustion of air O₂Film enrichment and the like.

Background

The energy crisis forces the high-energy consuming industry to abandon the original extensive production mode and draw together towards a more efficient energy-saving mode. The treatment of the industrial waste gas and the tail gas not only comprises the removal of smoke dust particles and acid gas, but also is an important step in industrial production because the emission reduction of greenhouse gas is increasingly strict in environmental protection requirements. The traditional process generally purifies the tail gas layer by layer through combining catalytic combustion with an activated carbon adsorption filtration process. The process not only consumes a large amount of energy, but also is tedious, low in efficiency and capable of improving the product cost. Gas membrane separation is a rapidly evolving gas separation technology. The membrane separation technology has the functions of separation, concentration, purification and refining, and has the characteristics of simple filtration process, easy control, molecular filtration and the like. Therefore, it has become one of the most important means for solving the energy and environmental problems in the fields of medicine, chemical industry, metallurgy, petroleum, water treatment, electronics, etc. If the membrane separation technology is applied to carbon dioxide removal and oxygen enrichment in air, energy consumption in the distillation process is reduced, the separation process does not involve phase change, the process is simple, the efficiency is high, and the membrane separation technology can be widely applied to gas separation. The polyimide material has the advantages of good solvent resistance, high temperature resistance, low thermal expansion coefficient and the like, and has good flexibility. Polyimide gas separation membranes have become an important choice for gas membrane separation, but the gas selectivity and the gas passing rate need to be further improved by changing the structure of a high molecular chain through different monomer structures, the gas separation efficiency is improved, and the energy consumption is reduced.

Disclosure of Invention

The invention aims to provide a preparation method of a polyimide film for separating carbon dioxide or enriching oxygen in air. It has been found that by using a monomer with polyaminobinaphthyl structure synthesized from a variety of dicarboxylic anhydride molecules to synthesize polyamide acid polymers, different side chain groups of the polyaminobinaphthyl monomer can change the gas selectivity and permeability of the film. After appropriate heat treatment, a polyimide film having a high separation coefficient and a high gas permeation rate was obtained. O of polyimide film under 0.8MPa of operating pressure₂/N₂The separation coefficient can reach 14.92, and the oxygen transmission rate is 238.71 barrer; CO 2₂/N₂The separation coefficient can reach 66.65, CO₂Has a transmission rate of 836.12 barrer.

The invention adopts the following technical scheme:

1) the 1,1' -bi-2-naphthol is nitrified by nitric acid to obtain a gray yellow powdery compound.

2) And (2) reducing the gray powdery compound obtained in the step (1) in hydrogen with the palladium-carbon catalysis of less than 2bar to obtain a pink solid.

3) The synthesis of the polyimide resin containing the binaphthyl structure adopts any one of the following methods a) or b):

chemical imidization process: mixing the polyaminobinaphthyl compound obtained in the step 2) and a proper amount of hexafluorodianhydride in a molar ratio of 0.8-1.2: 1 into a dry round-bottom flask, and 3-8mL of N, N-dimethylacetamide is added under the condition of an ice-water bath. Then 1-6mL of triethylamine and 1-6mL of acetic anhydride are added for chemical imidization for 12-36 hours. After the reaction was complete, the solid was precipitated and collected in methanol, washed clean and dried under vacuum at 200 ℃ overnight.

The constant boiling imidization process: putting the polyaminobinaphthyl compound obtained in the step 2) and a proper amount of hexafluoro dianhydride (the molar ratio is 0.8-1.2) into a dry round-bottom flask filled with a certain solvent, and stirring for 5-30 minutes at 10-40 ℃ under the protection of nitrogen. The schlenk tube is then warmed to 50-80 ℃ and held for 0.5-2 hours until the solution is completely dissolved. Then adding a proper amount of isoquinoline and o-dichlorobenzene, and then refluxing at 180-240 ℃ for 2-14 hours. After the reaction was complete, the solid was collected by settling in methanol and dried under vacuum at 200 ℃ overnight.

4) Preparing a polyimide film: dissolving the binaphthyl polyimide resin synthesized in the step 3) in chloroform to prepare 2-8 wt% of casting solution. Filtering the membrane casting solution by a 0.45 mu m polytetrafluoroethylene filter membrane to remove insoluble substances, and then placing the filtrate in a culture dish and uniformly paving the culture dish at the bottom of the dish. The culture dish with the membrane casting liquid is sealed in a self-sealing bag to slowly volatilize the solvent until the membrane is formed, and finally all the solvent is removed in a vacuum oven at the temperature of 180 ℃ and 240 ℃ for 10-48 hours.

5) The prepared binaphthyl polyimide gas separation membrane is further subjected to heat treatment in a carbonization furnace under the protection of nitrogen. The heating rate is 2-10 ℃/min and the temperature is respectively kept at 300-800 ℃ for 0.5-4 hours. And naturally cooling to room temperature after the heat treatment is finished.

The invention has the advantages that:

1) the distance between high molecular chains in the polyimide film can be adjusted through different side chain groups of the polyamino binaphthyl, so that the gas selectivity of the film is adjusted.

2) The permeation rate of the film is adjusted by controlling the aging temperature.

3) O of polyimide film₂/N₂The separation coefficient can reach 14.92, and the oxygen transmission rate is 238.71 barrer; CO 2₂/N₂The separation coefficient can reach 66.65, CO₂Has a transmission rate of 836.12 barrer.

Drawings

FIG. 1 monomer chemical Structure of polyimide resin

FIG. 2 is a schematic view of the chemical structure of a polyimide resin

FIG. 3 scanning electron micrograph of polyimide film

Detailed description of the preferred embodiments

The invention is further illustrated by the following specific embodiments in conjunction with the accompanying drawings:

according to the invention for O₂/N₂And CO₂/N₂The preparation method of the system gas separation membrane mainly comprises the following steps: the preparation method comprises the following steps of synthesis of a polyamino biphenyl monomer, preparation of biphenyl polyimide resin, preparation of a biphenyl polyimide casting solution and a film, and carbonization treatment of the biphenyl polyimide film.

Example 1:

0.62mL of concentrated nitric acid was added dropwise to an acetic acid solution containing 1.0g of 1,1' -bi-2-naphthol dissolved therein, and the mixture was stirred at room temperature for 1 hour. The mixture was then poured into ice water and the solid collected by filtration. The solid and 10% Pd/C catalyst were added to N, N-dimethylformamide solvent and reacted at room temperature under magnetic stirring in a hydrogen atmosphere of 2bar for 24 hours. After filtering through diatomite, pouring the filtrate into deionized water for sedimentation to obtain the biphenyldiamine monomer. Under the ice-water bath, 1.26mmol of biphenyldiamine monomer, 1.28mmol of hexafluoro dianhydride and 4.0mL of N, N-dimethylacetamide are put into a three-necked bottle and are stirred uniformly by magnetic force. Stirring was continued at 40 ℃ for 4 hours, and then 3mL of triethylamine and 3mL of anhydride were added and reacted at room temperature for 24 hours. After the reaction was complete, the solid was precipitated into methanol and collected, washed clean and dried under vacuum at 200 ℃ overnight. The binaphthyl polyimide resin was dissolved in chloroform to prepare a 5 wt% casting solution, and insoluble matter was filtered off through a 0.45 μm polytetrafluoroethylene filter. And uniformly spreading the membrane casting solution on the bottom of the dish in a culture dish, sealing the dish in a self-sealing bag, and slowly volatilizing the solvent until the membrane is formed. Finally, the polyimide film is subjected to vacuum oven at 200 ℃ for 10 hours to remove all the solvent. The prepared binaphthyl polyimide gas separation membrane is further subjected to heat treatment in a carbonization furnace under the protection of nitrogen. The temperature was raised at 5 ℃/min for 30 minutes at 550 ℃. And naturally cooling to room temperature after the heat treatment is finished. O of polyimide film at 0.8MPa₂/N₂The separation coefficient can reach 12.70, CO₂/N₂The separation coefficient can reach 53.28; n is a radical of₂，O₂And CO₂Through the use ofRates were 12.40, 157.53 and 660.98 barrers, respectively.

Example 2:

0.62mL of concentrated nitric acid was added dropwise to an acetic acid solution containing 1.0g of 1,1' -bi-2-naphthol dissolved therein, and the mixture was stirred at room temperature for 1 hour. The mixture was then poured into ice water and the solid collected by filtration. The solid obtained and a 10% Pd/C catalyst were added to N, N dimethylformamide solvent and reacted at room temperature under magnetic stirring in a hydrogen atmosphere of 2bar for 24 hours. After filtering through diatomite, pouring the filtrate into deionized water for sedimentation to obtain the biphenyldiamine monomer. Under the ice-water bath, 1.26mmol of biphenyldiamine monomer, 1.28mmol of 3,3 ', 4, 4' -benzophenonetetracarboxylic dianhydride and 4.0mL of N, N-dimethylacetamide were put into a three-necked flask and stirred by magnetic force. Stirring was continued at 40 ℃ for 4 hours, and then 3mL of triethylamine and 3mL of anhydride were added and reacted at room temperature for 24 hours. After the reaction was complete, the solid was precipitated into methanol and collected, washed clean and dried under vacuum at 200 ℃ overnight. The binaphthyl polyimide resin was dissolved in chloroform to prepare a 5 wt% casting solution, and insoluble matter was filtered off through a 0.45 μm polytetrafluoroethylene filter. And uniformly spreading the membrane casting solution on the bottom of the dish in a culture dish, sealing the dish in a self-sealing bag, and slowly volatilizing the solvent until the membrane is formed. Finally, the polyimide film is subjected to vacuum oven at 200 ℃ for 10 hours to remove all the solvent. The prepared binaphthyl polyimide gas separation membrane is further subjected to heat treatment in a carbonization furnace under the protection of nitrogen. The temperature was raised at 5 ℃/min for 30 minutes at 550 ℃. And naturally cooling to room temperature after the heat treatment is finished. O of polyimide film at 0.8MPa₂/N₂The separation coefficient can reach 11.58, CO₂/N₂The separation coefficient can reach 39.36; n is a radical of₂，O₂And CO₂The transmission rates were 13.24, 153.40 and 521.27 barrers, respectively.

Example 3:

0.62mL of concentrated nitric acid was added dropwise to an acetic acid solution containing 1.0g of 1,1' -bi-2-naphthol dissolved therein, and the mixture was stirred at room temperature for 1 hour. The mixture was then poured into ice water and the solid collected by filtration. The solid obtained and a 10% Pd/C catalyst were added to N, N dimethylformamide solvent and reacted at room temperature under magnetic stirring in a hydrogen atmosphere of 2bar for 24 hours. After the mixture is filtered by the diatomite,pouring the filtrate into deionized water for sedimentation to obtain the biphenyldiamine monomer. Under ice-water bath, 1.26mmol of biphenyldiamine monomer, 1.28mmol of 4, 4' -diphenyl ether dianhydride and 4.0mL of dimethylacetamide were put into a three-necked flask and stirred by magnetic force. Stirring was continued at 40 ℃ for 4 hours, and then 3mL of triethylamine and 3mL of anhydride were added and reacted at room temperature for 24 hours. After the reaction was complete, the solid was precipitated into methanol and collected, washed clean and dried under vacuum at 200 ℃ overnight. The binaphthyl polyimide resin was dissolved in chloroform to prepare a 5 wt% casting solution, and insoluble matter was filtered off through a 0.45 μm polytetrafluoroethylene filter. And uniformly spreading the membrane casting solution on the bottom of the dish in a culture dish, sealing the dish in a self-sealing bag, and slowly volatilizing the solvent until the membrane is formed. Finally, the polyimide film is subjected to vacuum oven at 200 ℃ for 10 hours to remove all the solvent. The prepared binaphthyl polyimide gas separation membrane is further subjected to heat treatment in a carbonization furnace under the protection of nitrogen. The temperature was raised at 5 ℃/min for 30 minutes at 550 ℃. And naturally cooling to room temperature after the heat treatment is finished. O of polyimide film at 0.8MPa₂/N₂The separation coefficient can reach 6.29, CO₂/N₂The separation coefficient can reach 22.23; n is a radical of₂，O₂And CO₂The transmission rates were 14.33, 90.11 and 318.52barrer, respectively.

Example 4:

0.62mL of concentrated nitric acid was added dropwise to an acetic acid solution containing 1.0g of 1,1' -bi-2-naphthol dissolved therein, and the mixture was stirred at room temperature for 1 hour. The mixture was then poured into ice water and the solid collected by filtration. The solid obtained and a 10% Pd/C catalyst were added to N, N dimethylformamide solvent and reacted at room temperature under magnetic stirring in a hydrogen atmosphere of 2bar for 24 hours. After filtering through diatomite, pouring the filtrate into deionized water for sedimentation to obtain the biphenyldiamine monomer. 4.8mmol of biphenyldiamine monomer, 4.8mmol of hexafluoro dianhydride and 7.25 mmol of LN-methyl pyrrolidone are added into a three-necked flask, stirred for 15 minutes at room temperature under the protection of nitrogen, and then heated to 60 ℃ and stirred for 30 minutes. After a drop of isoquinoline and 5mL of o-dichlorobenzene were added to the reaction system, the temperature was raised to 190 ℃ for 12 hours. After the reaction was complete, the solid was precipitated into methanol and collected, washed clean and dried under vacuum at 200 ℃ overnight. The binaphthyl polyimide resin was dissolved in chloroform to prepare5 wt% of the casting solution, and insoluble matter was filtered off through a 0.45 μm polytetrafluoroethylene filter. And uniformly spreading the membrane casting solution on the bottom of the dish in a culture dish, sealing the dish in a self-sealing bag, and slowly volatilizing the solvent until the membrane is formed. Finally, the polyimide film is subjected to a vacuum oven at 200 ℃ for 24 hours to remove all the solvent. The prepared binaphthyl polyimide gas separation membrane is further subjected to heat treatment in a carbonization furnace under the protection of nitrogen. The temperature was raised at 5 ℃/min for 30 minutes at 550 ℃. And naturally cooling to room temperature after the heat treatment is finished. O of polyimide film at 0.8MPa₂/N₂The separation coefficient can reach 5.13, CO₂/N₂The separation coefficient can reach 33.94; n is a radical of₂，O₂And CO₂The transmission rates were 2.02, 10.36 and 68.5barrer, respectively.

Example 5:

0.62mL of concentrated nitric acid was added dropwise to an acetic acid solution containing 1.0g of 1,1' -bi-2-naphthol dissolved therein, and the mixture was stirred at room temperature for 1 hour. The mixture was then poured into ice water and the solid collected by filtration. The solid obtained and a 10% Pd/C catalyst were added to N, N dimethylformamide solvent and reacted at room temperature under magnetic stirring in a hydrogen atmosphere of 2bar for 24 hours. After filtering through diatomite, pouring the filtrate into deionized water for sedimentation to obtain the biphenyldiamine monomer. 4.8mmol of biphenyldiamine monomer, 4.8mmol of hexafluoro dianhydride and 7.25 mmol of LN-methyl pyrrolidone are added into a three-necked flask, stirred for 15 minutes at room temperature under the protection of nitrogen, and then heated to 60 ℃ and stirred for 30 minutes. After a drop of isoquinoline and 5mL of o-dichlorobenzene were added to the reaction system, the temperature was raised to 190 ℃ for 12 hours. After the reaction was complete, the solid was precipitated into methanol and collected, washed clean and dried under vacuum at 200 ℃ overnight. The binaphthyl polyimide resin was dissolved in chloroform to prepare a 5 wt% casting solution, and insoluble matter was filtered off through a 0.45 μm polytetrafluoroethylene filter. And uniformly spreading the membrane casting solution on the bottom of the dish in a culture dish, sealing the dish in a self-sealing bag, and slowly volatilizing the solvent until the membrane is formed. Finally, the polyimide film is subjected to a vacuum oven at 200 ℃ for 24 hours to remove all the solvent. The prepared binaphthyl polyimide gas separation membrane is further subjected to heat treatment in a carbonization furnace under the protection of nitrogen. The temperature was raised at 5 ℃/min for 30 minutes at 550 ℃. And naturally cooling to room temperature after the heat treatment is finished. Polyimide at 0.8MPaO of imine film₂/N₂The separation coefficient can reach 13.81, CO₂/N₂The separation coefficient can reach 66.65; n is a radical of₂，O₂And CO₂The transmission rates were 12.54, 173.29 and 836.12 barrers, respectively.

The invention is shown in figure 1, which shows the chemical structure of the monomer of the polyimide resin, wherein figure 1a is the chemical structure of the polyamino binaphthyl monomer, and figure 1b is the chemical structure of the dianhydride monomer. FIG. 2 shows a schematic diagram of the chemical structure of the polyimide resin prepared by the present invention, and a scanning electron micrograph of the polyimide resin is shown in FIG. 3.

Claims

1. a preparation method containing a polyimide film of binaphthalene structure is characterized in that comprising the following steps:

1) Preparation of 6,6-dinitro-1,1'-bi-2-naphthol: add 0.4-0.8 mL of nitric acid to 0.6-1.5 g of 1,1'-bi-2-naphthalene under ice-water bath conditions phenolic acetic acid solution, and then continue stirring at 10-40 ° C for 1-4 hours. After the reaction is completed, the mixture is poured into ice water, and the gray-yellow solid powder is collected by filtration;

2) Preparation of 6,6-diamino-1,1'-bi-2-naphthol: add the compound obtained in step 1) and 2%-10% Pd/C catalyst to N,N-dimethylformamide , stir evenly with magnetic force, then react at room temperature for 12-48 hours in a hydrogen atmosphere of 1-2bar, after the reaction, filter and concentrate with diatomaceous earth to obtain the product;

3) The synthesis of polyimide resin containing binaphthalene structure adopts any method in the following a) or b):

a) Chemical imidization process: Weigh the polyaminobinaphthylamine monomer synthesized in step 2) and hexafluorodianhydride in a molar ratio of 0.8-1.2:1 and add it to a dry round-bottomed flask, and then add it in an ice-water bath. Add 3-8 mL of N,N-dimethylacetamide, stir evenly, heat up to 40°C and continue the reaction for 4 hours, then add 1-6 mL of triethylamine and 1-6 mL of acetic anhydride for chemical imidization for a total of 12- After 36 hours, after the reaction is completed, precipitate and collect the solid in methanol, clean and dry under vacuum at 120-200 °C overnight;

b) azeotropic imidization process: put the polyaminobinaphthylamine monomer and hexafluorodianhydride obtained in step 2) into a three-necked flask containing 5-15mL of N-methylpyrrolidone according to a molar ratio of 1:1, and at 10 -40°C, stir for 5-30 minutes under nitrogen protection, then warm up to 50-80°C and hold for 0.5-2 hours until the solution is completely clear, then add 1-5 drops of isoquinoline and 3-8mL of o-dichloro Benzene, then refluxed at 180-240°C for 2-14 hours, after the reaction was completed, the solid was collected by sedimentation in methanol, and vacuum-dried at 200°C overnight;

4) Preparation of polyimide film: the binaphthalene polyimide resin synthesized in step 3) in a) or b) is dissolved in chloroform to prepare a 2-10 wt% casting solution, and the casting solution uses polytetrafluoroethylene Filter the membrane, place the filtrate in a petri dish and evenly spread the bottom of the dish. The petri dish with the casting solution is sealed in a self-sealing bag and slowly evaporate the solvent until the film is formed. Finally, put it in a vacuum oven at 180-240 °C for 10-48 Remove all the solvent in hours;

5) The prepared binaphthalene polyimide gas separation membrane is further heat-treated in a carbonization furnace under nitrogen protection, the heating rate is 2-10°C/min, and the temperature is maintained at 300-800°C for 0.5-4 hours, and the temperature is naturally lowered after the heat treatment. to room temperature;

The obtained polyimide resin has the following general structural formula:

R:-OH,-CH ₃ ,-COOH,-OCH ₃ ,-OCOCH3,-COOCH ₃

Ar:

2. the preparation method that contains binaphthalene structure polyimide film according to claim 1 is characterized in that step 1) and 2) have the synthesis of polyamino binaphthyl monomer molecule, obtain by steps such as nitration, reduction with Polyamino-modified binaphthyl monomers with different side chains.

3. the preparation method that contains binaphthalene structure polyimide film according to claim 1 is characterized in that in step 4), after filtering through 0.45 μm polytetrafluoroethylene filter membrane, the filtrate is placed in a petri dish to be sealed in the filtrate. The solvent is slowly evaporated in the ziplock bag until the film is formed, and finally all the solvent is removed in a vacuum oven at 180-240°C for 12-48 hours.

4. The purposes of a polyimide film containing a binaphthyl structure, characterized in that it is used for _CO ₂ /N separation, and the polyimide film containing a binaphthyl structure is any one of claims 1-3. prepared films.

5. The purposes of the polyimide film containing binaphthalene structure according to claim 4, characterized in that: under the pressure of 0.8MPa, the separation coefficient of N ₂ /CO ₂ of the polyimide film is 20-70 ; the gas flux of N ₂ is 10-20 barrer and the gas flux of CO ₂ is 500-800 barrer.

6 . The use of the polyimide film containing a binaphthalene structure according to claim 5 , wherein the variation of the test gas separation coefficient is maintained at ±3% under the same pressure after the film is tested for 15-30 days. 7 .