Disclosure of Invention
The purpose of the invention is as follows: the invention provides a method for synthesizing a copolymer by using soybean seed coat peroxidase catalysis, which aims to overcome the defects of low reaction efficiency, low conversion rate and the like in the prior art.
The technical scheme is as follows: in order to solve the technical problems, the technical scheme adopted by the invention is as follows:
a method for synthesizing a copolymer by using soybean seed coat peroxidase catalysis comprises the following steps:
mixing the monomer 1, the monomer 2, the chain transfer agent, the soybean seed coat peroxidase, the initiator and the solvent under the inert gas atmosphere condition, preheating, adding an oxidant under the inert gas atmosphere condition, and reacting to obtain the soybean seed coat peroxidase;
the monomer 1 is selected from acrylic acid or acrylamide compounds, and the monomer 2 is selected from vinyl polyether macromonomers.
Preferably, the monomer 1 is selected from N, N-Dimethylacrylamide (DMA), N-Hydroxyethylacrylamide (HEAA), Acrylic Acid (AA), hydroxyethyl acrylate (HEA) or N-isopropylacrylamide (NIPAM), and the structure is shown as follows.
Preferably, the monomer 2 is selected from vinyl polyether macromonomers, and the structural formula is as follows:
in the formula R1Is H or methyl, R2Is H or 1 &Alkyl of 4 carbon atoms, X ═ COO, O (CH)2)mO、CH2O or CH2CH2O and m are integers of 2-4; AO is selected from one or more of oxyalkylene groups with 2-4 carbon atoms, and n is the average addition mole number of AO and is an integer of 20-100; (AO)nCan be a homopolymerized structure, a random copolymerization structure, a diblock structure or a multiblock copolymerization structure. The method comprises the following specific steps:
preferably, the chain transfer agent CTA is selected from one or more of the following formulae:
preferably, the initiator is acetylacetone (ACAC), dibenzoyl peroxide (BOP) or potassium persulfate, and the structure is as follows:
preferably, the oxidizing agent is hydrogen peroxide (H)2O2)。
Preferably, the solvent is a mixed solution of Phosphate Buffer Solution (PBS)/dimethyl sulfoxide (DMSO), and the pH value is 6-8.
Preferably, the molar ratio of the monomer 1 to the chain transfer agent is 100-160: 1, the molar ratio of the chain transfer agent to the soybean seed coat peroxidase to the initiator to the oxidant is 1: 0.0005-0.001: 6:0.3, and the molar ratio of the monomer 1 to the monomer 2 is 2-5: 1.
Preferably, the reaction time is 30-120 min, and the reaction temperature is 25-35 ℃.
Preferably, after the reaction is finished, adding an organic solvent into the reaction solution, quenching, separating and purifying to obtain the copolymer of the macromonomer 1-the macromonomer 2.
The catalyst is soybean seed coat peroxidase, and the active center of the catalyst is shown as follows:
soybean seed coat peroxidase is a heme protein consisting of a single peptide chain and porphyrin iron, has a molecular weight of about 37KD and consists of more than 300 amino acid residues. The soybean seed coat peroxidase consists of two different structural domains, and a heme prosthetic group with a catalytic active center is embedded in the middle of the soybean seed coat peroxidase. It has an isoelectric point of 3.9 and belongs to acidic proteins. It contains Fe (III) -protoporphyrin IX prosthetic group, one tryptophan, 4 disulfide bonds, 2 Ca2+And 8 polysaccharides. Compared with the catalytic enzyme in the prior art, the catalytic enzyme has higher stability and catalytic activity.
The invention utilizes the advantages of the novel biological enzyme catalyst, leads the reaction to be mild and efficient, constructs a reaction unit aiming at the specific catalyst, the active monomer and the inactive monomer, and realizes the promotion of the polymerization reaction rate and the optimization of the molecular weight distribution; by means of the unique advantages of enzyme catalysis, the polymerization rate of the inactive monomer is improved, and the efficient copolymerization of different monomers is realized; provides a new technical reference for the polymerization of vinyl polyether macromonomer and other inactive monomers.
Has the advantages that: compared with the prior art, the method utilizes the process of the novel bio-enzyme catalysis, combines the advantages of the enzyme catalysis, reserves the catalytic efficiency of the catalyst on different monomers, improves the reaction rate, optimizes the process flow, and has the advantages of safety, high efficiency, greenness and controllable molecular weight; meanwhile, the soybean seed coat peroxidase is cheap and easy to obtain, has low cost and provides a basis for industrial production.
Detailed Description
The invention will be better understood from the following examples. However, those skilled in the art will readily appreciate that the description of the embodiments is only for illustrating the present invention and should not be taken as limiting the invention as detailed in the claims.
In the following examples of the present invention, the molecular weight and molecular weight distribution of the product were measured by the following methods.
Using a Wyatt size exclusion chromatography system, a GPC column equipped with an SSI 1500 pump, a Wyatt OptilabEX detector, Waters Styragel HR;
analysis conditions were as follows: the mobile phase is N, N-dimethylformamide, the flow rate is 0.7mL/min, the column temperature is 25 ℃, and the sample injection volume is 0.4 mL.
Sample measurement: taking a pure sample of 2mg, adding 1mLN, N-dimethylformamide solution for dilution, filtering by using a disposable filter head, and taking 4mL of solution for sample measurement.
In the following examples of the present invention, the conversion C represents the molar ratio of the reacted monomers to the total amount of the starting monomers and can be calculated as follows:
C=(na/n0)*100%
wherein C represents the conversion of the monomer, naDenotes the molar amount of monomer reacted, n0Representing the total molar amount of the initial monomers.
Example 1
Assuming that the molar ratio of the monomer 1 to the chain transfer agent to the catalyst to the initiator to the oxidant is 120:1:0.00081:6:0.3, the molar ratio of the monomer 1 to the monomer 2 is 3:1, the monomer 1 is DMA, and the monomer 2 is APEG2300. 12.26mg of CTA1, 6.56g of DMA, 39.25g of TPEG2300And a mixed solution of 250ml PBS and DMSO (PBS/DMSO 26:74v/v, [ PBS)]20mM, pH 6) is added into a reaction bottle and stirred evenly, 19.13mg of soybean seed coat peroxidase and 0.33g of ACAC are added into the reaction bottle, the reaction bottle is sealed and placed into an ice water bath for nitrogen blowing and oxygen discharging for 30min, then the reaction bottle is placed into an oil bath at the temperature of 30 ℃, after the temperature is stabilized, 100 mu L of deoxygenated H is put into a micro syringe2O2The solution was injected into a reaction flask to initiate polymerization. After 2h of polymerization under nitrogen atmosphere, the reaction flask was placed in an ice-water bath and oxygen was introduced to quench the reaction. Adding a large amount of methanol into the reaction solution, and stirringThen precipitating for 4h at low temperature, filtering, collecting precipitate, drying in a vacuum drying oven for 48h, and analyzing by size exclusion chromatography and nuclear magnetic hydrogen spectrum to obtain a result that the conversion rate of the high-activity monomer DMA is 98 percent and the conversion rate of the low-activity monomer APEG is low2300The conversion was 91%, and the number average molecular weight of the resulting copolymer was 89.26kg/mol, and the molecular weight distribution index was 1.02. Wherein the content of P (DMA) chain link is 83 percent, P (APEG)2300) The chain link content was 17%.
Example 2
Assuming that the molar ratio of the monomer 1 to the chain transfer agent to the catalyst to the initiator to the oxidant is 130:1:0.00081:6:0.3, the molar ratio of the monomer 1 to the monomer 2 is 4:1, the monomer 1 is HEAA, and the monomer 2 is APEG2300. 12.26mg of CTA1, 7.47g of HEAA, 37.37g of APEG2300And a mixed solution of 200ml PBS and DMSO (PBS/DMSO 26:74v/v, [ PBS)]20mM, pH 6) was added to the flask and stirred uniformly, 19.13mg of soybean seed coat peroxidase and 0.56g of BOP were added thereto, the flask was sealed, the flask was placed in an ice water bath and purged with nitrogen for 30min, then the flask was placed in an oil bath at 30 ℃ and, after the temperature stabilized, 100. mu.L of deoxygenated H was injected using a micro syringe2O2The solution was injected into a reaction flask to initiate polymerization. After 2h of polymerization under nitrogen atmosphere, the reaction flask was placed in an ice-water bath and oxygen was introduced to quench the reaction. Adding a large amount of methanol into the reaction solution, stirring, precipitating at low temperature for 4h, filtering, collecting precipitate, drying in a vacuum drying oven for 48h, and analyzing by size exclusion chromatography and nuclear magnetic hydrogen spectrum to obtain high-activity monomer HEAA with conversion rate of 98% and low-activity monomer APEG2300The conversion was 90%, the number-average molecular weight of the resulting copolymer was 92.18kg/mol, and the molecular weight distribution index was 1.09. Wherein the content of P (HEAA) chain unit is 88%, and P (APEG)2300) The chain link content was 12%.
Example 3
Assuming that the molar ratio of the monomer 1 to the chain transfer agent to the catalyst to the initiator to the oxidant is 130:1:0.0006:6:0.3, the molar ratio of the monomer 1 to the monomer 2 is 3:1, the monomer 1 is AA, and the monomer 2 is APEG4000. 12.26mg of CTA2, 4.6g of AA, 40.26g of APEG4000And a mixed solution of 250ml PBS and DMSO (PBS/DMSO 26:74v/v, [ PBS)]20mM, pH 7) was added to the reaction flask and stirred well, followed by addition of 19.1Sealing 3mg soybean seed coat peroxidase and 0.33g ACAC, placing the reaction bottle in ice water bath, blowing nitrogen to remove oxygen for 30min, placing in oil bath at 30 deg.C, after temperature is stable, using microinjector to remove oxygen 100 μ L H2O2The solution was injected into a reaction flask to initiate polymerization. After 2h of polymerization under nitrogen atmosphere, the reaction flask was placed in an ice-water bath and oxygen was introduced to quench the reaction. Adding a large amount of methanol into the reaction solution, stirring, precipitating at low temperature for 4h, filtering, collecting precipitate, drying in a vacuum drying oven for 48h, and analyzing by size exclusion chromatography and nuclear magnetic hydrogen spectrum to obtain a high-activity monomer AA conversion rate of 95% and a low-activity monomer APEG4000The conversion was 92%, the number average molecular weight of the resulting copolymer was 79.80kg/mol, and the molecular weight distribution index was 1.09. Wherein the content of P (AA) chain unit is 76 percent, and P (APEG)4000) The chain link content was 24%.
Example 4
Assuming that the molar ratio of the monomer 1 to the chain transfer agent to the catalyst to the initiator to the oxidant is 140:1:0.00081:6:0.3, the molar ratio of the monomer 1 to the monomer 2 is 5:1, the monomer 1 is HEA, and the monomer 2 is HPEG2300. 12.26mg of CTA, 7.58g of HEA, 34.86g of HPEG2300And a mixed solution of 200mL of PBS and DMSO (PBS/DMSO 26:74v/v, [ PBS)]20mM, pH 7) is added into a reaction bottle and stirred evenly, 19.13mg of soybean seed coat peroxidase and 0.33g of ACAC are added into the reaction bottle, the reaction bottle is sealed and placed into an ice water bath for nitrogen blowing and oxygen discharging for 30min, then the reaction bottle is placed into an oil bath at the temperature of 30 ℃, after the temperature is stabilized, 100 mu L of deoxygenated H is put into a micro syringe2O2The solution was injected into a reaction flask to initiate polymerization. After 2h of polymerization under nitrogen atmosphere, the reaction flask was placed in an ice-water bath and oxygen was introduced to quench the reaction. Adding a large amount of methanol into the reaction solution, stirring, precipitating at low temperature for 4h, filtering, collecting precipitate, drying in a vacuum drying oven for 48h, and analyzing by size exclusion chromatography and nuclear magnetic hydrogen spectrum to obtain monomer HPEG with high activity and high conversion rate of HEA 95% and low activity2300The conversion was 95%, the number average molecular weight of the resulting copolymer was 75.24kg/mol, and the molecular weight distribution index was 1.10. Wherein the content of P (HEA) chain unit is 86%, and P (HPEG)2300) The chain link content was 14%.
Example 5
Assuming that the molar ratio of the monomer 1 to the chain transfer agent to the catalyst to the initiator to the oxidant is 100:1:0.00081:6:0.3, the molar ratio of the monomer 1 to the monomer 2 is 4:1, the monomer 1 is DMA, and the monomer 2 is HPEG4000. 12.26mg of CTA3, 5.42g of DMA, 31.16g of HPEG4000And a mixed solution of 200ml PBS and DMSO (PBS/DMSO 26:74v/v, [ PBS)]20mM, pH 8) was added to the reaction flask and stirred uniformly, 19.13mg of soybean seed coat peroxidase and 0.33g of potassium persulfate were added thereto, the flask was sealed, the flask was placed in an ice water bath and purged with nitrogen for 30min, then the flask was placed in an oil bath at 30 ℃ and, after the temperature stabilized, 100. mu.L of deoxygenated H was put in an oil bath using a micro syringe2O2The solution was injected into a reaction flask to initiate polymerization. After 2h of polymerization under nitrogen atmosphere, the reaction flask was placed in an ice-water bath and oxygen was introduced to quench the reaction. Adding a large amount of methanol into the reaction solution, stirring, precipitating at low temperature for 4h, filtering, collecting precipitate, drying in a vacuum drying oven for 48h, and analyzing by size exclusion chromatography and nuclear magnetic hydrogen spectrum to obtain a low-activity monomer HPEG with high DMA conversion rate of 93% and high DMA conversion rate of high-activity monomer4000The conversion was 90%, the number average molecular weight of the resulting copolymer was 72.58kg/mol, and the molecular weight distribution index was 1.15. Wherein the content of P (DMA) chain links is 90 percent, and P (HPEG)4000) The chain link content was 10%.
Example 6
Assuming that the molar ratio of the monomer 1 to the chain transfer agent to the catalyst to the initiator to the oxidant is 100:1:0.001:6:0.3, the molar ratio of the monomer 1 to the monomer 2 is 4:1, the monomer 1 is AA, and the monomer 2 is TPEG2300. 12.26mg of CTA3, 4.5g of AA, 28.23g of TPEG2300And a mixed solution of 200mL of PBS and DMSO (PBS/DMSO 26:74v/v, [ PBS)]20mM, pH 8) was added to the reaction flask and stirred uniformly, 19.13mg of soybean seed coat peroxidase and 0.33g of ACAC were added thereto, the flask was sealed, the flask was placed in an ice water bath and purged with nitrogen for 30min, then the flask was placed in an oil bath at 30 ℃ and, after the temperature was stabilized, 100. mu.L of deoxygenated H was put in an oil bath using a micro syringe2O2The solution was injected into a reaction flask to initiate polymerization. After 2h of polymerization under nitrogen atmosphere, the reaction flask was placed in an ice-water bath and oxygen was introduced to quench the reaction. A large amount of methanol was added to the reaction solution,stirring, low-temperature precipitating for 4h, filtering, collecting precipitate, drying in vacuum drying oven for 48h, and analyzing by size exclusion chromatography and nuclear magnetic hydrogen spectrum to obtain high-activity monomer AA with conversion rate of 94% and low-activity monomer TPEG2300The conversion was 91%, the number-average molecular weight of the resulting copolymer was 58.54kg/mol, and the molecular weight distribution index was 1.12. Wherein the content of P (AA) chain unit is 83%, and P (TPEG)2300) The chain link content was 17%.