A polylysine rich in 1,3-dicarbonyl side chains and its preparation method and application

Abstract

The present invention discloses a polylysine rich in 1,3-dicarbonyl side chains and a preparation method and application thereof. The main chain structure of the polylysine is L -Configuration Polymerization α ‑amino acid, the side chain is a substituent containing a 1,3‑dicarbonyl functional group, and its structural formula is as follows: ;wherein the R group is methyl, methoxy or phenyl; n is an integer ranging from 40 to 95. The present invention uses L‑N‑tert-butyloxycarbonyl‑lysine starting material to synthesize N‑phenoxycarbonyllysine polymerization monomers containing 1,3‑dicarbonyl side chains, and such monomers undergo polymerization reaction under the action of an initiator to obtain polylysine rich in 1,3‑dicarbonyl side chains as in formula I. The polylysine prepared by the present invention is rich in 1,3‑dicarbonyl side chains, has the characteristics of low cost, safety and non-toxicity, can be complexed with copper ions and manganese ions in wastewater to achieve the purpose of purifying metal ion pollution, and the removal capacity of copper ion sewage can reach 75%, while the removal capacity of manganese ion sewage can reach 82%.

Description

Technical Field

[0001] The invention belongs to the field of preparation of new materials for metal wastewater treatment, and specifically relates to polylysine rich in 1,3-dicarbonyl side chains and a preparation method and application thereof. Background Art

[0002] With the continuous development of modern industry, the discharge of heavy metal wastewater is increasing day by day. Since heavy metal wastewater is non-biodegradable, it greatly harms human health. Efficient prevention and control of heavy metal wastewater has become an urgent issue.

[0003] At present, common treatment methods for heavy metal wastewater include chemical treatment, physical treatment and biological treatment. Chemical treatment methods include chemical precipitation, electrochemical method, etc.; physical treatment methods include adsorption and membrane separation; biological treatment methods mainly include biosorption, bioflocculation and phytoremediation. Among all heavy metal wastewater treatment methods, adsorption has the advantages of simple operation, wide source of materials and wide application range, and has broad development prospects. However, the treatment of heavy metal pollution in water bodies by adsorption is greatly affected by the adsorption materials. Therefore, the development of adsorption materials for heavy metal wastewater treatment with independent intellectual property rights has broad market value.

[0004] Adsorption is a classic method for treating heavy metal wastewater. It has always been favored because of its advantages such as simple operation and modifiable adsorbents. Adsorption is a method of removing heavy metal ions from wastewater by utilizing the binding force between the adsorption active surface and heavy metal ions. Common adsorption active groups include hydroxyl, thiol, carboxyl, amino, etc. These groups form cage molecules with a network structure by forming ionic bonds, hydrogen bonds or covalent bonds with metal ions, thereby effectively adsorbing heavy metal ions in the solution. However, existing commercially available adsorbents often face the dilemma of too low adsorption flux and secondary pollution. Therefore, the development of new high adsorption flux and degradable adsorption materials has extremely high economic value. Summary of the invention

[0005] In view of the above technical problems existing in the prior art, the object of the present invention is to provide a polylysine rich in 1,3-dicarbonyl side chains and a preparation method and application thereof.

[0006] The technical solution adopted by the present invention is as follows:

[0007] The polylysine rich in 1,3-dicarbonyl side chains has a main structure of L-configuration poly-α-amino acid and a side chain of a substituent containing a 1,3-dicarbonyl functional group, and its structural formula is shown in Formula I:

[0008] ;

[0009] In the formula, the R group is methyl, methoxy or phenyl; n is an integer ranging from 40 to 95.

[0010] Furthermore, the polylysine rich in 1,3-dicarbonyl side chains has a molecular weight of 10.0×10 3 -26.1×10 3 g / mol, its chiral configuration is L - configuration, the polymer type is polylysine.

[0011] The method for preparing polylysine rich in 1,3-dicarbonyl side chains of the present invention comprises the following steps:

[0012] Step 1: In the presence of EDCI and DMAP, LN-tert-butyloxycarbonyl-lysine reacts with substituted β-carbonyl propionic acid in DMF solvent and is stirred at room temperature overnight. After the reaction is completed, post-treatment is performed to obtain L-6-(N- β -carbonyl substituted propionyl)-N-tert-butyloxycarbonyl lysine, recorded as intermediate 1, the reaction formula is as follows:

[0013] ;

[0014] Step 2: The intermediate 1 obtained in step 1 was reacted with trifluoroacetic acid in DCM solvent under stirring. After the reaction was completed, the solvent was removed by concentration under reduced pressure to obtain L-6-(N- β -carbonyl substituted propionyl) lysine, recorded as intermediate 2, the reaction formula is as follows:

[0015] ;

[0016] Step 3: In the presence of pyridine, the intermediate 2 obtained in step 2 reacts with phenyl chloroformate in DCM solvent and is stirred at room temperature overnight. After the reaction is completed, post-treatment is performed to obtain L-6-(N- β -carbonyl substituted propionyl)-N-formylphenyl ester-lysine, recorded as intermediate 3, the reaction formula is as follows:

[0017] ;

[0018] Step 4: Dissolve the intermediate 3 obtained in step 3 in DMF, add benzylamine and diisopropylethylamine as initiators, react at 70-85°C for 60-80h under nitrogen protection, and after the reaction, add the reaction solution dropwise into 2-5°C n-hexane to precipitate; filter, wash the precipitate with 2-5°C ethyl acetate to remove the reacted monomer, and dry to obtain the corresponding 1,3-dicarbonyl side chain-rich polylysine, the reaction formula is as follows:

[0019] ;

[0020] The substituent R in the structural formula of the substituted β-oxopropionic acid and the substituent R in the structural formula of the intermediate 1-3 are the same as R in formula I.

[0021] Furthermore, in step 1, the molar ratio of the substituted β-carbonyl propionic acid to LN-tert-butyloxycarbonyl-lysine is 1.5-3:1, and the molar amounts of EDCI and DMAP are 1.5-3 times and 0.05-0.2 times the molar amount of LN-tert-butyloxycarbonyl-lysine, respectively; the post-treatment step after the reaction in step 1 is: adding ethyl acetate to dilute the reaction solution, washing the reaction solution with 5-15% citric acid aqueous solution, saturated sodium bicarbonate aqueous solution and saturated sodium chloride aqueous solution, respectively, combining the organic phases, drying with magnesium sulfate and concentrating under reduced pressure to obtain a crude product, and the crude product is purified by column chromatography, and the mobile phase is ethyl acetate / petroleum ether in a volume ratio of 1:2-5, to obtain the intermediate 1.

[0022] Further, in step 2, the molar amount of trifluoroacetic acid in step 2 is 3-8 times the molar amount of the intermediate, the reaction temperature is room temperature, and the reaction time is 20-30 hours.

[0023] Furthermore, in step 3, the molar amount of pyridine is 1.5-3 times the molar amount of intermediate 2, and the molar amount of phenyl chloroformate is 3-8 times the molar amount of intermediate 2. The post-treatment step after the reaction in step 3 is as follows: the reaction solution is washed with 5-15% citric acid aqueous solution, saturated sodium bicarbonate aqueous solution and saturated sodium chloride aqueous solution, respectively, the organic phases are combined, dried with magnesium sulfate and concentrated under reduced pressure to obtain a crude product, and the crude product is purified by column chromatography, and the mobile phase is ethyl acetate / petroleum ether in a volume ratio of 1:3-8 to obtain the intermediate 3.

[0024] Furthermore, in step 4, the molar ratio of benzylamine to diisopropylethylamine is 1:0.8-1.2, and the total amount of the two substances is 1 / 30 of the amount of the intermediate 3 substance.

[0025] The present invention also discloses the use of the polylysine rich in 1,3-dicarbonyl side chains in treating heavy metal ion wastewater, wherein the heavy metal is copper and / or manganese, and the treatment method is: adding the polylysine rich in 1,3-dicarbonyl side chains into the heavy metal ion wastewater, adjusting the pH to 8-11, stirring at room temperature for 3-5 days, and after the reaction is completed, centrifuging to remove the polylysine rich in 1,3-dicarbonyl side chains.

[0026] By adopting the above technology, compared with the prior art, the beneficial effects of the present invention are as follows:

[0027] 1) The present invention uses naturally abundant amino acid derivatives as starting materials to prepare side chain base polyester amides, and the production cost is low; secondly, the preparation route adopted by the present invention is simple, and only four steps of reaction are required to obtain the corresponding polyamino acid; finally, such polyamino acid materials have high metal ion adsorption performance, and the removal capacity of copper ion wastewater can reach 75%, and the removal capacity of manganese ion wastewater can reach 82%.

[0028] 2) The adsorbent of the present invention is a polyamino acid, which is non-toxic and will not cause secondary environmental pollution. The raw material source is abundant and the price is low. It is well known in the art that polyamino acid compounds have good biodegradability. The polyamino acid adsorbent of the present invention has high adsorption efficiency for copper ions. However, the adsorption efficiency of existing similar polymers for copper ions is mostly less than 30%. DETAILED DESCRIPTION

[0029] The present invention is further described below in conjunction with embodiments, but the protection scope of the present invention is not limited thereto.

[0030] 1. Preparation of polymer monomers Example 1

[0031] 1) Preparation of L-6-(N-acetoacetoxy)-N-tert-butyloxycarbonyllysine, intermediate 1

[0032] ;

[0033] 5.0 mmol of LN-tert-butyloxycarbonyl-lysine was dissolved in 10 mL of N,N-dimethylformamide (DMF), and then 10.0 mmol of acetoacetic acid, 10.0 mmol of 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride (EDCI) and 0.5 mmol of 4-dimethylaminopyridine (DMAP) were added successively and stirred at room temperature for 16 hours. After the reaction was completed, ethyl acetate was added to dilute the reaction solution, and the reaction solution was washed with 10% citric acid aqueous solution, saturated sodium bicarbonate aqueous solution and saturated sodium chloride aqueous solution respectively. The organic phases were combined, dried with magnesium sulfate and concentrated under reduced pressure to obtain a crude product. The crude product was purified by column chromatography with a mobile phase of ethyl acetate / petroleum ether in a volume ratio of 1 / 3, and dried to obtain the corresponding L-6-(N-acetoacetoxy)-N-tert-butyloxycarbonyl-lysine, i.e., intermediate 1, with a yield of 92%. The product structure was characterized by hydrogen nuclear magnetic resonance spectroscopy.

[0034] 1 H-NMR (400 MHz, DMSO- d6), δ 8.02 (brs, 1H), 7.28 (brs, 1H), 4.48(m,1H), 3.63 (s, 2H), 2.98 (m, 2H), 2.25 (s, 3H), 1.72-1.58 (m, 4H), 1.18 (s,9H), 1.02 (m, 2H) ppm. The active hydrogen of the carboxyl group is not shown in the NMR spectrum.

[0035] 2) Preparation of L-6-(N-acetoacetoxy)lysine, intermediate 2

[0036] ;

[0037] 3.0 mmol of the intermediate 1 obtained in step 1 was dissolved in dichloromethane (DCM, 10 mL), and 15 mmol of trifluoroacetic acid was added and stirred at room temperature for 24 hours. After the reaction was completed, L-6-(N-acetoacetoxy)lysine, i.e., intermediate 2, was obtained by concentration under reduced pressure with a yield of 95%. The product structure was characterized by hydrogen nuclear magnetic resonance spectroscopy.

[0038] 1 H-NMR (400 MHz, DMSO- d 6), δ 8.81 (brs, 2H), 8.01 (brs, 1H), 3.64 (s,2H), 3.45 (m, 1H), 3.02 (m, 2H), 2.18 (s, 3H), 1.68-1.22 (m, 6H) ppm. The active hydrogen on the carboxyl group was not observed in the H NMR spectrum.

[0039] 3) Preparation of L-6-(N-acetoacetoxy)-N-formylphenyl ester-lysine, intermediate 3

[0040] ;

[0041] 3.0 mmol of L-6-(N-acetylacetoxy)lysine obtained in step 2, i.e., intermediate 2, was dissolved in 10 mL DCM solution containing pyridine (6 mmol), and then phenyl chloroformate (15 mmol) was added dropwise and stirred at room temperature for 16 hours. After the reaction was completed, the reaction solution was washed with 10% citric acid aqueous solution, saturated sodium bicarbonate aqueous solution, and saturated sodium chloride aqueous solution, respectively. The organic phases were combined, dried over magnesium sulfate, and concentrated under reduced pressure to obtain the corresponding crude product. The crude product was purified by column chromatography with a mobile phase of ethyl acetate / petroleum ether in a volume ratio of 1 / 5, and dried to obtain L-6-(N-acetylacetoxy)-N-formylphenyl ester-lysine, i.e., intermediate 3, with a yield of 83%. The product structure was characterized by hydrogen nuclear magnetic resonance spectroscopy.

[0042] 1 H-NMR (400 MHz, DMSO- d 6), δ 7.98 (brs, 1H), 7.48-7.31 (m, 6H), 4.58(m, 1H), 3.66 (s, 2H), 2.97 (m, 2H), 2.25 (s, 3H), 1.68-1.22 (m, 6H) ppm. The active hydrogen on the carboxyl group was not observed in the H NMR spectrum. Example 2

[0043] 1) Preparation of L-6-(N-malonic acid monomethyl ester)-N-tert-butyloxycarbonyl lysine, intermediate 1

[0044] ;

[0045] 5.0 mmol of LN-tert-butyloxycarbonyl-lysine was dissolved in 10 mL of N,N-dimethylformamide (DMF), and then 10.0 mmol of monomethyl malonate, EDCI (10.0 mmol) and 0.5 mmol of 4-dimethylaminopyridine (DMAP) were added successively and stirred at room temperature for 16 hours. After the reaction was completed, ethyl acetate was added to dilute the reaction solution, and the reaction solution was washed with 10% citric acid aqueous solution, saturated sodium bicarbonate aqueous solution and saturated sodium chloride aqueous solution respectively. The organic phases were combined, dried over magnesium sulfate and concentrated under reduced pressure to obtain a crude product. The crude product was purified by column chromatography with a mobile phase of ethyl acetate / petroleum ether in a volume ratio of 1 / 3, and dried to obtain the corresponding L-6-(N-monomethyl malonate)-N-tert-butyloxycarbonyl-lysine, i.e., intermediate 1, with a yield of 88%. The product structure was characterized by hydrogen nuclear magnetic resonance spectroscopy.

[0046] 1 H-NMR (400 MHz, DMSO- d 6), δ 7.98 (brs, 1H), 7.32 (brs, 1H), 4.46 (m,1H), 3.68 (s, 3H), 3.58 (s, 2H), 2.97 (m, 2H), 1.72-1.58 (m, 4H), 1.18 (s,9H), 1.02 (m, 2H) ppm. The active hydrogen on the carboxyl group was not observed in the H NMR spectrum.

[0047] 2) Preparation of L-6-(N-malonic acid monomethyl ester) lysine

[0048] ;

[0049] 3.0 mmol of the intermediate 1 obtained in step 1 was dissolved in dichloromethane (DCM), and 15 mmol of trifluoroacetic acid was added and stirred at room temperature for 24 hours. After the reaction was completed, L-6-(N-malonic acid monomethyl ester) lysine, i.e., intermediate 2, was obtained by concentration under reduced pressure with a yield of 90%. The product structure was characterized by hydrogen nuclear magnetic resonance spectroscopy.

[0050] 1 H-NMR (400 MHz, DMSO- d 6), δ 8.78 (brs, 2H), 7.98 (brs, 1H), 3.67 (s,3H), 3.52 (s, 2H), 3.45 (m, 1H), 3.02 (m, 2H), 1.66-1.19 (m, 6H) ppm. The active hydrogen on the hydroxyl group was not observed in the H NMR spectrum.

[0051] 3) Preparation of L-6-(N-malonic acid monomethyl ester)-N-formylphenyl ester-lysine, i.e. intermediate 3

[0052] ;

[0053] 3.0 mmol of L-6-(N-malonic acid monomethyl ester) lysine obtained in step 2, namely intermediate 2, was dissolved in a DCM solution containing pyridine (6 mmol), and then phenyl chloroformate (15 mmol) was added dropwise and stirred at room temperature for 16 hours. After the reaction was completed, the reaction solution was washed with 10% citric acid aqueous solution, saturated sodium bicarbonate aqueous solution and saturated sodium chloride aqueous solution respectively. The organic phases were combined, dried over magnesium sulfate and concentrated under reduced pressure to obtain a crude product. The crude product was purified by column chromatography with a mobile phase of ethyl acetate / petroleum ether in a volume ratio of 1 / 5, and dried to obtain the corresponding L-6-(N-malonic acid monomethyl ester)-N-formylphenyl ester-lysine, namely intermediate 3, with a yield of 80%. The product structure was characterized by hydrogen nuclear magnetic resonance spectrum.

[0054] 1 H-NMR (400 MHz, DMSO- d 6), δ 8.02 (brs, 1H), 7.38-7.25 (m, 6H), 4.54(m, 1H), 3.67 (s, 3H), 3.52 (s, 2H), 3.02 (m, 2H), 1.70-1.23 (m, 6H) ppm. The active hydrogen on the hydroxyl group was not observed in the H NMR spectrum. Example 3

[0055] 1) Preparation of L-6-(N-benzoylacetoxy)-N-tert-butyloxycarbonyllysine, intermediate 1

[0056] ;

[0057] 5.0 mmol of LN-tert-butyloxycarbonyl-lysine was dissolved in 10 mL of N,N-dimethylformamide (DMF), and then 10.0 mmol of benzoylacetic acid, EDCI (10.0 mmol) and 0.5 mmol of 4-dimethylaminopyridine (DMAP) were added successively and stirred at room temperature for 16 hours. After the reaction was completed, ethyl acetate was added to dilute the reaction solution. The reaction solution was washed with 10% citric acid aqueous solution, saturated sodium bicarbonate aqueous solution and saturated sodium chloride aqueous solution respectively. The organic phases were combined, dried over magnesium sulfate and concentrated under reduced pressure to obtain a crude product. The crude product was purified by column chromatography with a mobile phase of ethyl acetate / petroleum ether in a volume ratio of 1 / 3, and dried to obtain the corresponding L-6-(N-benzoylacetoxy)-N-tert-butyloxycarbonyl-lysine, i.e., intermediate 1, with a yield of 84%. The product structure was characterized by hydrogen nuclear magnetic resonance spectroscopy.

[0058] 1 H-NMR (400 MHz, DMSO- d 6), δ 7.98-7.55 (m, 6H), 7.36 (brs, 1H), 4.53(m, 1H), 3.46 (s, 2H), 2.98 (m, 2H), 1.72-1.58 (m, 4H), 1.18 (s, 9H), 1.02(m, 2H) ppm. The active hydrogen on the hydroxyl group was not observed in the H NMR spectrum.

[0059] 2) Preparation of L-6-(N-benzoylacetoxy)lysine, intermediate 2

[0060] ;

[0061] 3.0 mmol of the intermediate 1 obtained in step 1 was dissolved in dichloromethane (DCM), and 15 mmol of trifluoroacetic acid was added to react at room temperature for 24 hours. After the reaction was completed, L-6-(N-benzoylacetoxy)lysine, i.e., intermediate 2, was obtained by concentration under reduced pressure with a yield of 93%. The product structure was characterized by hydrogen nuclear magnetic resonance spectroscopy.

[0062] 1 H-NMR (400 MHz, DMSO- d6), δ 8.78 (brs, 2H), 7.98-7.55 (m, 6H), 3.48(s, 2H), 3.39 (m, 1H), 3.02 (m, 2H), 1.72-1.26 (m, 6H) ppm. The active hydrogen on the hydroxyl group was not observed in the H NMR spectrum.

[0063] 3) Preparation of L-6-(N-benzoylacetoxy)-N-formylphenyl ester-lysine, intermediate 3

[0064] ;

[0065] 3.0 mmol of L-6-(N-benzoyl acetate) lysine obtained in step 2, i.e., intermediate 2, was dissolved in a DCM solution containing pyridine (6 mmol), and then phenyl chloroformate (15 mmol) was added dropwise and stirred at room temperature for 16 hours. After the reaction was completed, the reaction solution was washed with 10% citric acid aqueous solution, saturated sodium bicarbonate aqueous solution, and saturated sodium chloride aqueous solution, respectively. The organic phases were combined, dried over magnesium sulfate, and concentrated under reduced pressure to obtain a crude product. The crude product was purified by column chromatography with a mobile phase of ethyl acetate / petroleum ether in a volume ratio of 1 / 5, and dried to obtain the corresponding L-6-(N-benzoyl acetate)-N-formylphenyl ester-lysine, i.e., intermediate 3, with a yield of 85%. The product structure was characterized by hydrogen nuclear magnetic resonance spectroscopy.

[0066] 1 H-NMR (400 MHz, DMSO- d 6), δ 8.02-7.58 (m, 6H), 7.42-7.35 (m, 6H),4.56 (m, 1H), 3.45 (s, 2H), 3.02 (m, 2H), 1.69-1.24 (m, 6H) ppm. The active hydrogen on the hydroxyl group was not observed in the H NMR spectrum.

[0067] 2. Preparation of 1,3-dicarbonyl side chain polylysine

[0068] Example 4

[0069] Preparation of Poly-L-6-(N-acetoacetoxy)-lysine

[0070] ;

[0071] 350 mg of L-6-(N-acetoacetoxy)-N-formylphenyl ester-lysine (i.e., intermediate 3 prepared in Example 1) was dissolved in 5 mL of DMF, and benzylamine and diisopropylethylamine were added as initiators (the molar ratio of benzylamine to diisopropylethylamine was 1:1, and the total amount of the two substances was 1 / 30 of the amount of the intermediate 3 substance). o C for 72 hours under nitrogen protection. After the reaction, the reaction solution was added dropwise to a cold n-hexane solution (4 o C) precipitate. Filter and wash with cold ethyl acetate (4 o C) Wash to remove unreacted monomers and dry to obtain poly-L-6-(N-acetoacetoxy)lysine, 150 mg, with a yield of 72%. The molecular weight of the polymer was characterized by gel permeation chromatography, and the test results showed that its molecular weight was 11.2×10 3 g / mol, and the average degree of polymerization is 53.

[0072] The yield of the polymer product in Example 4 of the present invention is calculated as follows:

[0073] Yield = (actual mass of polymer product / theoretical mass of polymer product) × 100%;

[0074] The theoretical mass of the polymer product = (molecular weight of the polymerized monomer, i.e., intermediate 3 - molecular weight of phenoxycarbonyl) × the amount of substance of intermediate 3;

[0075] The yields of subsequent polymer products are calculated according to this method, the same below.

[0076] Example 5

[0077] Preparation of Poly (L-6-(N-methylmalonate)-lysine)

[0078] ;

[0079] 366 mg of L-6-(N-malonic acid monomethyl ester) lysine (i.e., intermediate 3 prepared in Example 2) was dissolved in 5 mL of DMF, and benzylamine and diisopropylethylamine were added as initiators (the molar ratio of benzylamine to diisopropylethylamine was 1:1, and the total amount of the two substances was 1 / 30 of the amount of the intermediate 3 substance). o C for 72 hours under nitrogen protection. After the reaction, the reaction solution was added dropwise to a cold n-hexane solution (4 o C) precipitate. Filter and wash with cold ethyl acetate (4 o C) Wash to remove unreacted monomers and dry to obtain poly (L-6-(N-malonic acid monomethyl ester) lysine, 160 mg, yield 70%. The molecular weight of the polymer was characterized by gel permeation chromatography, and the test results showed that its molecular weight was 18.5×103 g / mol, and the average degree of polymerization is 81.

[0080] Example 6

[0081] Preparation of Poly-L-6-(N-benzoylacetoxy)-lysine

[0082] ;

[0083] 412 mg of L-6-(N-benzoylacetoxy)lysine (i.e., intermediate 3 prepared in Example 3) was dissolved in 5 mL of DMF, and benzylamine and diisopropylethylamine were added as initiators (the molar ratio of benzylamine to diisopropylethylamine was 1:1, and the total amount of the two substances was 1 / 30 of the amount of the intermediate 3 substance). o C for 72 hours under nitrogen protection. After the reaction, the reaction solution was added dropwise to a cold n-hexane solution (4 o C) precipitate. Filter and wash with cold ethyl acetate (4 o C) Wash to remove unreacted monomers and dry to obtain poly (L-6-(N-benzoyl acetate) lysine, 225 mg, with a yield of 82%. The molecular weight of the polymer was characterized by gel permeation chromatography, and the test results showed that its molecular weight was 26.1×10 3 g / mol, and the average degree of polymerization is 95.

[0084] 3. Adsorption of copper / manganese ions in wastewater by 1,3-dicarbonyl side chain polylysine Example 7

[0085] 100 mg of polylysine prepared in Examples 4-6 was added to a deionized copper ion solution or a deionized manganese ion solution with a metal ion concentration of 0.2 g / mL (5 mL, solution pH = 10.0, the anion of the copper / manganese ion is chloride ion). o After stirring for 4 days under C conditions, the polylysine was removed by centrifugation after the reaction was completed. The concentration of copper ions / manganese ions in the supernatant was detected by inductively coupled plasma optical emission spectrometry (ICP-OES). The copper / manganese ion removal rate was determined by the percentage of the ion concentration in the solution after the reaction to the ion concentration in the solution before the reaction, and the results are shown in Table 1.

[0086] .

Claims

1. A method for preparing polylysine rich in 1,3-dicarbonyl side chains, characterized in that The steps include: Step 1: In the presence of EDCI and DMAP, LN-tert-butyloxycarbonyl-lysine reacts with substituted β-carbonyl propionic acid in DMF solvent and is stirred at room temperature overnight. After the reaction is completed, post-treatment is performed to obtain L-6-(N- β -carbonyl substituted propionyl)-N-tert-butyloxycarbonyl lysine, recorded as intermediate 1, the reaction formula is as follows: ； Step 2: The intermediate 1 obtained in step 1 was reacted with trifluoroacetic acid in DCM solvent under stirring. After the reaction was completed, the solvent was removed by concentration under reduced pressure to obtain L-6-(N- β -carbonyl substituted propionyl) lysine, recorded as intermediate 2, the reaction formula is as follows: ； Step 3: In the presence of pyridine, the intermediate 2 obtained in step 2 reacts with phenyl chloroformate in DCM solvent and is stirred at room temperature overnight. After the reaction is completed, post-treatment is performed to obtain L-6-(N- β -carbonyl substituted propionyl)-N-formylphenyl ester-lysine, recorded as intermediate 3, the reaction formula is as follows: ； Step 4: Dissolve the intermediate 3 obtained in step 3 in DMF, add benzylamine and diisopropylethylamine as initiators, react at 70-85°C for 60-80h under nitrogen protection, and after the reaction, add the reaction solution dropwise into 2-5°C n-hexane to precipitate; filter, wash the precipitate with 2-5°C ethyl acetate to remove the reacted monomer, and dry to obtain the corresponding 1,3-dicarbonyl side chain-rich polylysine, the reaction formula is as follows: ； The substituent R in the structural formula of the substituted β-oxopropionic acid and the substituent R in the structural formula of the intermediate 1-3 are the same as R in formula I.

2. The method for preparing a polylysine rich in 1,3-dicarbonyl side chains as claimed in claim 1, characterized in that In step 1, the molar ratio of the substituted β-carbonyl propionic acid to LN-tert-butyloxycarbonyl-lysine is 1.5-3:1, and the molar amounts of EDCI and DMAP are 1.5-3 times and 0.05-0.2 times the molar amount of LN-tert-butyloxycarbonyl-lysine, respectively; the post-treatment step after the reaction in step 1 is: adding ethyl acetate to dilute the reaction solution, washing the reaction solution with 5-15% citric acid aqueous solution, saturated sodium bicarbonate aqueous solution and saturated sodium chloride aqueous solution, respectively, combining the organic phases, drying with magnesium sulfate and concentrating under reduced pressure to obtain a crude product, and purifying the crude product by column chromatography, and the mobile phase is ethyl acetate / petroleum ether in a volume ratio of 1:2-5, so as to obtain the intermediate 1.

3. The method for preparing a polylysine rich in 1,3-dicarbonyl side chains as claimed in claim 1, characterized in that In step 2, the molar amount of trifluoroacetic acid in step 2 is 3-8 times of 1 mole of the intermediate, the reaction temperature is room temperature, and the reaction time is 20-30 hours.

4. The method for preparing polylysine rich in 1,3-dicarbonyl side chains according to claim 1, characterized in that In step 3, the molar amount of pyridine is 1.5-3 times the molar amount of intermediate 2, and the molar amount of phenyl chloroformate is 3-8 times the molar amount of intermediate 2. The post-treatment step after the reaction in step 3 is as follows: the reaction solution is washed with 5-15% citric acid aqueous solution, saturated sodium bicarbonate aqueous solution and saturated sodium chloride aqueous solution, respectively, the organic phases are combined, dried with magnesium sulfate and concentrated under reduced pressure to obtain a crude product, and the crude product is purified by column chromatography, and the mobile phase is ethyl acetate / petroleum ether in a volume ratio of 1:3-8, to obtain the intermediate 3.

5. The method for preparing a polylysine rich in 1,3-dicarbonyl side chains as claimed in claim 1, characterized in that In step 4, the molar ratio of benzylamine to diisopropylethylamine is 1:0.8-1.2, and the total amount of the two substances is 1 / 30 of the amount of the intermediate 3 substance.

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