A preparation method of aminoquinoline metal aluminum catalyst and its application in synthesizing degradable polymer materials

Abstract

The invention discloses a preparation method of an aminoquinoline metal aluminum catalyst and its application in synthesizing degradable polymer materials. The preparation method of the aminoquinoline metal aluminum catalyst comprises the following steps: dissolving an organic ligand in 20 mL of anhydrous solvent under a nitrogen atmosphere, adding 1.0 to 1.5 molar equivalents of trimethylaluminum, and reacting at room temperature for 12 to 24 hours under nitrogen protection; removing the solvent under reduced pressure, and washing three times with a poor solvent to obtain an aminoquinoline skeleton-based metal aluminum catalyst. The aminoquinoline metal aluminum catalyst of the invention is an efficient lactone ring-opening polymerization catalyst. The invention introduces a quinoline skeleton, improves the high temperature resistance of the catalyst, and can conveniently regulate the model space effect and electronic effect by changing the substituent group of the ligand to achieve different catalytic properties; it can be used to catalyze the ring-opening polymerization of caprolactone, and has the characteristics of high activity, good controllability, and low catalyst load; the prepared polycaprolactone polymer material has a controllable molecular weight and a low molecular weight distribution.

Description

Technical Field

[0001] The invention relates to a preparation method of a metal aluminum catalyst based on an aminoquinoline skeleton and application of the catalyst in lactone ring-opening polymerization. Background Art

[0002] With the limited global fossil fuel resources, the development of sustainable and degradable polymers will become increasingly important. For this reason, biodegradable polymers have become an attractive alternative. Among the various known biodegradable polymers, linear aliphatic polyesters such as polycaprolactone (PCL), polylactide (PLA), polyglycolide (PGA), etc. occupy a prominent position and have been rapidly developed in recent years. Among them, PCL is an engineering material with considerable development potential and application prospects. It has good biocompatibility and biodegradability. It can be completely biodegraded in 6-12 months under natural conditions, does not cause any pollution to the environment, and can be used in tissue engineering scaffolds and drug delivery systems. In addition, PCL is also developing into the industrial field and is used for the production and processing of plastic materials.

[0003] A simple and efficient method for synthesizing PCL is the ring-opening polymerization (ROP) of cyclic esters using metal complexes as catalysts, including aluminum (Inorg. Chem., 2015, 54, 4699; Organometallics, 2014, 33, 6474), rare earth metals (Organometallics, 2014, 33, 309; Polym. Chem., 2013, 4, 360), titanium and zirconium (Organometallics, 2008, 27, 5632; Macromolecules, 2000, 33, 725), magnesium and zinc (Organometallics, 2016, 35, 189; Inorg. Chem., 2016, 55, 5365; J. Am. Chem. Soc., 2002, 124, 15239), tin and iron (Macromolecules, 2000, 33, 1964; J. Am. Chem. Soc., 2002, 124, 4384) complexes. One of the most commonly used catalysts in industry is stannous octoate, which is an effective catalyst for most cyclic esters. It is easy to handle and has high catalytic activity, but there are also side reactions such as transesterification, which is manifested as a decrease in control of polymerization, resulting in a wider molecular weight distribution. In recent years, metal aluminum catalysts with auxiliary ligands have been widely studied due to their excellent performance in the ring-opening polymerization of cyclic esters. Its superiority is manifested in that ROP can be carried out in a controlled manner to provide high molecular weight PCL under mild conditions and can also show the characteristics of "living" polymerization, thereby enabling the preparation of materials with predictable molecular weight and narrow dispersity.

[0004] The present invention reports a method for preparing an aminoquinoline metal aluminum catalyst and its application in synthesizing degradable polymer materials. The present invention introduces a quinoline skeleton to improve the chemical stability of the catalyst. By introducing different substituents into the ligand, the spatial effect and electronic effect of the model metal catalyst can be easily regulated to achieve low catalyst load and high activity catalytic performance, and to prepare degradable polymer materials such as PCL and PLA with different molecular weights and narrow distributions. Summary of the invention

[0005] The purpose of the present invention is to provide a method for preparing an aminoquinoline metal aluminum catalyst and application thereof in synthesizing a degradable polymer material.

[0006] The present invention provides an aminoquinoline metal aluminum catalyst represented by formula (I):

[0007]

[0008] Among them, R 1 is selected from bromine, methyl, chlorine; R 2 is selected from isopropyl, chloro, diphenylmethyl; R 3 Selected from hydrogen and isopropyl.

[0009] Preferably, the aluminum metal complex of the present invention is selected from any one of the following complexes:

[0010] Al1:R 1 =Br,R 2 = i Pr,R 3 =H;

[0011] Al2:R 1 =Me,R 2 = i Pr,R 3 =H;

[0012] Al3:R 1 =Cl,R 2 = i Pr,R 3 =H;

[0013] Al4:R 1 =Br,R 2 =Cl,R 3 =H;

[0014] Al5:R 1 =Br,R 2 =CH(Ph)2,R 3 = i Pr.

[0015] The present invention provides a method for preparing the aminoquinoline metal aluminum catalyst, which comprises the following steps:

[0016] (1) Under nitrogen atmosphere, 8-R 1 -2-Formaldehyde-quinoline and substituted aniline are mixed in a molar ratio of 0.8-1.2:0.8-1.5, and a catalytic amount of 5-20 mg of p-toluenesulfonic acid is added, and the mixture is stirred and reacted for 12-24 hours in a mixed solvent of methanol and dichloromethane (the volume ratio of methanol to dichloromethane is 1:1-5); the mixed solvent is removed under reduced pressure, and the obtained product is washed with ethanol and filtered and dried to obtain an organic ligand; under a nitrogen atmosphere, the organic ligand is dissolved in an anhydrous solvent, and 1.0-1.5 molar equivalents of trimethylaluminum are added, and the mixture is stirred and reacted at room temperature for 12-24 hours; the solvent is removed under reduced pressure, and the mixture is washed with a poor solvent to obtain an aminoquinoline metal aluminum catalyst.

[0017] In the above preparation method, the anhydrous solvent is selected from benzene, toluene, xylene, and tetrahydrofuran; the poor solvent is selected from n-hexane, n-pentane, n-heptane, and cyclohexane.

[0018] The present invention also provides the use of the aminoquinoline metal aluminum catalyst represented by the above formula (I) in catalyzing the lactone ring-opening polymerization reaction.

[0019] In the above application, the lactone includes one or more of caprolactone, lactide, glycolide, butyrolactone, valerolactone, enantholactone and octanolactone.

[0020] In the above application, the molar ratio of the aminoquinoline metal aluminum catalyst to the lactone is 1:10 to 10000.

[0021] In the above application, the solvent for the polymerization reaction can be benzene, toluene, n-hexane, tetrahydrofuran and dichloromethane.

[0022] In the above application, the polymerization reaction temperature is 0°C to 110°C.

[0023] In the above application, the polymerization reaction time is 5 minutes to 12 hours.

[0024] In the above application, alcohol can be added as a co-catalyst in the polymerization reaction, and the alcohol is methanol, ethanol, isopropanol, n-butanol, ethylene glycol, glycerol, benzyl alcohol; the molar ratio of the alcohol to the aminoquinoline metal aluminum catalyst is 0 to 100:1.

[0025] The aminoquinoline metal aluminum catalyst provided by the present invention is easy to prepare, low in cost, stable in nature, and has high catalytic activity. It is particularly suitable for catalyzing lactone ring-opening polymerization and has the characteristics of high activity and good controllability. By controlling the polymerization reaction conditions, the molecular weight of the polymer can be adjusted from several thousand to several hundred thousand. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 This is the crystal structure diagram of compound Al1.

[0027] Figure 2 This is the crystal structure diagram of compound Al2.

[0028] Figure 3 This is the GPC chart of the polymer obtained in Example 16.

[0029] Figure 4 This is the GPC chart of the polymer obtained in Example 22.

[0030] Figure 5 This is the GPC chart of the polymer obtained in Example 23.

[0031] Figure 6 This is the GPC chart of the polymer obtained in Example 24.

[0032] Figure 7 This is the GPC chart of the polymer obtained in Example 25.

[0033] Figure 8 This is the MALDI TOF chart of the polymer obtained in Example 12.

[0034] Fig. 9 This is the MALDI TOF chart of the polymer obtained in Example 21. DETAILED DESCRIPTION

[0035] The present invention is further described by way of examples, but the present invention is not limited thereto. The examples of the present invention can enable those skilled in the art to understand the present invention more comprehensively.

[0036] Unless otherwise specified, the experimental methods used in the following examples are conventional methods.

[0037] Unless otherwise specified, the materials and reagents used in the following examples can be obtained from commercial sources.

[0038] The ligands 8-bromo-2-(CH=N-C6H3-2,6-isopropyl)-quinoline, 8-bromo-2-(CH=N-C6H3-2,6-chloro)-quinoline, and 8-bromo-2-(CH=N-C6H2-2,6-diphenylmethyl-4-isopropyl)-quinoline in the present invention are synthesized according to the method reported in the literature Macromolecules, 2022, 55, 2433.

[0039] Example 1. Preparation of ligand 8-methyl-2-(CH=N-C6H3-2,6-isopropyl)-quinoline

[0040] 8-Methyl-2-formaldehyde-quinoline (1.70 g, 10 mmol), 2,6-diisopropylaniline (1.95 g, 11 mmol) and 20 mg of p-toluenesulfonic acid were added to a mixed solution of methanol and dichloromethane. The mixture was stirred overnight at 25°C, the solvent was removed under reduced pressure, and the mixture was washed with ethanol and filtered to obtain 2.7 g of yellow powdery solid ligand 8-methyl-2-(CH=N-C6H3-2,6-isopropyl)-quinoline, with a yield of 81%. 1 H NMR(CDCl3): δ8.49(s,1H),8.40(d,J=8.5Hz,1H),8.26(d,J=8.5Hz,1H),7.74(d,J=8.0Hz,1H),7.62(d,J=6.9H z,1H),7.54–7.47(m,1H),7.22–7.10(m,3H),3.03(hept,J=6.9Hz,2H),2.85(s,3H),1.21(d,J=6.9Hz,12H)ppm. 13 C NMR(CDCl3): δ164.27,153.61,149.11,147.28,138.10,137.05,136.68,129.80,12 9.01,127.29,125.56,124.68,123.16,117.68,28.17,23.18,17.67ppm.Anal.Calcd for C 23 H 26 N2:C,83.59;H,7.93;N,8.48.Found:C,83.85;H,7.82;N,8.33.

[0041] Example 2: Preparation of ligand 8-chloro-2-(CH=N-C6H3-2,6-isopropyl)-quinoline

[0042] The method is the same as that in Example 1, except that 8-chloro-2-formaldehyde-quinoline is used instead of 8-methyl-2-formaldehyde quinoline to obtain 3.6 g of the compound ligand 8-chloro-2-(CH=N-C6H3-2,6-isopropyl)-quinoline with a yield of 92%. 1 H NMR(CDCl3): δ8.56(s,1H),8.51(d,J=8.5Hz,1H),8.32(d,J=8.5Hz,1H),7.88(dd,J=7.5,1.3Hz,1H),7.83(dd, J=8.2,1.2Hz,1H),7.58–7.50(m,1H),7.23–7.10(m,3H),2.98(hept,J=6.9Hz,2H),1.20(d,J=6.9Hz,12H)ppm. 13C NMR(CDCl3): δ163.29,155.16,148.27,144.31,137.19,136.96,134.17,130.39 ,130.04,127.63,126.87,124.60,123.02,119.03,28.00,23.35ppm.Anal.Calcd for C 22 H 23 ClN2:C,75.31;H,6.61;N,7.98.Found:C,75.24;H,6.56;N,8.04.

[0043] Example 3. Preparation of Catalyst Al1

[0044] Under nitrogen atmosphere, 8-bromo-2-(CH=N-C6H3-2,6-isopropyl)-quinoline (0.79 g, 2 mmol) was dissolved in 20 mL of toluene solvent, trimethylaluminum (2 mL, 1 M in hexane) was added and stirred at room temperature overnight. After the solvent was removed under reduced pressure, n-hexane (3×10 mL) was added for washing to obtain a yellow solid Al1 compound (0.87 g, 1.7 mmol, yield 93%). 1 H NMR(C6D6): δ7.42(dd,J=7.6,1.5Hz,1H),7.38–7.32(m,1H),7.30–7.24(m,2H),7.13(s,1H) ,6.89(dd,J=8.1,1.4Hz,1H),6.66(d,J=8.5Hz,1H),6.56(t,J=7.8Hz,1H),4.67(q,J=6.8Hz, 1H),4.43(hept,J=6.9Hz,1H),3.17(hept,J=6.9Hz,1H),1.52(dd,J=6.9,6.9Hz,6H),1.44( d,J=6.8Hz,3H),1.31(d,J=7.0Hz,3H),1.25(d,J=6.8Hz,3H),0.07(s,3H),-0.06(s,3H)ppm. 13 C NMR(C6D6): δ173.96,148.36,147.59,147.32,141.68,139.83,136.15,128.16,126.92,124.41,123.84,123 .18,120.74,118.60,66.33,27.97,27.49,26.34,25.23,25.10,24.02,23.96,-2.24,-3.34ppm.Anal.Calcd for C 25 H 32AlBrN2:C,64.24;H,6.90;N,5.99.Found:C,64.08;H,6.88;N,5.75.

[0045] Example 4. Preparation of Catalyst Al2

[0046] The experimental steps were the same as those in Example 3, and the catalyst Al2 yield was 0.76 g, 1.9 mmol, 94%. 1 H NMR(C6D6): δ7.38–7.30(m,2H),7.26(dd,J=6.5,2.5Hz,2H),7.05(t,J=8.3Hz,2H),6. 95(t,J=7.5Hz,1H),6.72(d,J=8.5Hz,1H),4.68(q,J=6.7Hz,1H),4.39(hept,J=7.0Hz, 1H),3.18(hept,J=6.8Hz,1H),3.01(s,3H),1.49(dd,J=6.9,1.8Hz,6H),1.43(d,J=6. 7Hz,3H),1.32(d,J=6.9Hz,3H),1.24(d,J=6.8Hz,3H),-0.08(s,3H),-0.20(s,3H)ppm. 13 C NMR(C6D6): δ171.91,148.39,147.50,147.03,143.64,140.51,133.84,133.22,128.47,127.08,126.60,124.53,12 3.96,123.25,119.64,66.27,28.00,27.49,26.58,25.38,25.19,24.25,23.99,21.79,-3.34,-5.25ppm.Anal.Calcd for C 26 H 35 AlN2:C,77.57;H,8.76;N,6.96.Found:C,77.52;H,8.81;N,6.82.

[0047] Example 5. Preparation of Catalyst Al3

[0048] The experimental steps were the same as those in Example 3, and the yield of catalyst Al3 was 0.75 g, 1.8 mmol, 89%. 1H NMR(C6D6): δ7.38–7.32(m,1H),7.31–7.24(m,2H),7.19–7.17(m,1H),7.15(d,J= 1.5Hz,1H),6.87–6.82(m,1H),6.65(t,J=8.0Hz,2H),4.68(q,J=6.8Hz,1H),4.44( hept,J=6.9Hz,1H),3.19(hept,J=6.9Hz,1H),1.54–1.49(m,6H),1.43(d,J=6.8Hz ,3H),1.33(d,J=7.0Hz,3H),1.26(d,J=6.8Hz,3H),0.03(s,3H),-0.10(s,3H)ppm. 13 C NMR(C6D6): δ173.56,148.41,147.39,147.33,140.28,139.66,131.96,129.00,128.58,127.28,126.60,124.42 ,123.83,123.18,120.65,66.15,27.98,27.45,26.49,25.28,25.13,23.98,23.91,-3.33,-5.37ppm.Anal.Calcd for C 26 H 32 AlN2:C,70.99;H,7.63;N,6.62.Found:C,70.86;H,7.72;N,6.45.

[0049] Example 6. Preparation of Catalyst Al4

[0050] The experimental steps were the same as those in Example 3, and the yield of catalyst Al4 was 0.81 g, 1.8 mmol, 90%. 1 H NMR(C6D6): δ7.40(dd,J=7.5,1.5Hz,1H),7.36–7.18(m,2H),7.13(d,J=8.5Hz,1H),6.90(dd,J=8.1,1.4Hz,1H),6.64(d,J=8.5H z,1H),6.58(t,J=7.8Hz,1H),6.47(t,J=8.0Hz,1H),5.19(q,J=6.8Hz,1H),1.47(d,J=6.8Hz,3H),0.19(s,3H),-0.03(s,3H)ppm. 13C NMR(C6D6): δ173.14,148.65,141.47,140.11,136.08,129.25,128.97,128.18 ,126.91,122.11,120.78,118.55,62.48,25.33,-2.10,-4.48ppm.Anal.Calcd for C 19 H 18 AlBrCl2N2:C,50.47;H,4.01;N,6.20.Found:C,50.51;H,4.02;N,6.02.

[0051] Example 7. Preparation of Catalyst Al5

[0052] The experimental steps were the same as those in Example 3. The yield of catalyst Al5 was 1.38 g, 1.9 mmol, 91%. 1 H NMR(C6D6): δ7.65–7.50(m,4H),7.47(dd,J=7.5,1.5Hz,1H),7.32(d,J=2.3Hz,1H),7.28–7. 33(m,2H),7.18(s,1H),7.16(dd,J=6.3,2.3Hz,3H),7.10–6.95(m,8H),6.93–6.84(m,6H),6. 62(t,J=7.8Hz,1H),6.18(d,J=8.5Hz,1H),5.79(s,1H),4.50(q,J=6.8Hz,1H),2.61(hept,J= 6.9Hz,1H),1.10(d,J=6.9Hz,3H),1.06(dd,J=6.9,5.5Hz,6H),0.14(s,3H),0.12(s,3H)ppm. 13 C NMR(C6D6): δ173.75,148.66,146.65,145.78,145.63,144.24,141.44,141.12,140 .91,140.60,138.48,135.34,129.64,129.46,128.97,128.73,128.53,128.44,128 .13,127.39,127.31,127.28,127.24,126.15,124.91,124.83,124.69,120.92,117 .68,64.54,51.34,50.57,32.61,24.23,23.13,22.92,-1.97,-2.97ppm.Anal.Calcd for C 48 H 46AlBrN2:C,76.08;H,6.12;N,3.70.Found:C,76.15;H,6.23;N,3.54.

[0053] Example 8: Polymerization of ε-caprolactone catalyzed by catalyst Al1

[0054] In a Schlenk bottle, under anhydrous and oxygen-free conditions, add 0.228g of ε-caprolactone, 20μmol of complex Al1 (9.4mg) dissolved in 2mL TOL, and add to the Schlenk bottle with a syringe to initiate polymerization. Control the reaction temperature at 90℃ for 5min, add 1mL of 5% acetic acid methanol solution, pour into methanol to precipitate the polymer, filter and vacuum dry for 24 hours to obtain polycaprolactone. Conversion rate: 5%.

[0055] Example 9: Polymerization of ε-caprolactone catalyzed by catalyst Al1 and benzyl alcohol

[0056] In a Schlenk bottle, under anhydrous and oxygen-free conditions, add 0.228g of ε-caprolactone, add 2.1μL of benzyl alcohol (20μmol), and dissolve 20μmol of complex Al1 (9.4mg) in 2mL TOL. Use a syringe to add it to the Schlenk bottle to initiate polymerization. Control the reaction temperature at 30℃ for 10min, add 1mL of 5% acetic acid methanol solution, pour it into methanol to precipitate the polymer, filter it, and vacuum dry it for 24 hours to obtain polycaprolactone. Conversion rate: 5%.

[0057] Example 10: Polymerization of ε-caprolactone catalyzed by catalyst Al1 and benzyl alcohol

[0058] In a Schlenk bottle, under anhydrous and oxygen-free conditions, add 0.228g of ε-caprolactone, add 2.1μL of benzyl alcohol (20μmol), and 20μmol of complex Al1 (9.4mg) dissolved in 2mL TOL, and add it to the Schlenk bottle with a syringe to initiate polymerization. Control the reaction temperature at 50℃ for 5min, add 1mL of 5% acetic acid methanol solution, pour it into methanol to precipitate the polymer, filter it and vacuum dry it for 24 hours to obtain polycaprolactone. Conversion rate: 54%. The number average molecular weight M of the polycaprolactone is n :4.3×10 3 g / mol, molecular weight distribution PDI = 1.08. The number average molecular weight was determined by gel permeation chromatography, Agilent 1260 Infinity, THF as solvent, flow rate 1 mL min -1 , test temperature 40℃.

[0059] Example 11: Polymerization of ε-caprolactone catalyzed by catalyst Al1 and benzyl alcohol

[0060] In a Schlenk bottle, under anhydrous and oxygen-free conditions, add 0.228g of ε-caprolactone, add 2.1μL of benzyl alcohol (20μmol), and 20μmol of complex Al1 (9.4mg) dissolved in 2mL TOL, and add it to the Schlenk bottle with a syringe to initiate polymerization. Control the reaction temperature at 70℃ for 5min, add 1mL of 5% acetic acid methanol solution, pour it into methanol to precipitate the polymer, filter it and vacuum dry it for 24 hours to obtain polycaprolactone. Conversion rate: 77%. The number average molecular weight M of the polycaprolactone is n :8.3×10 3 g / mol, molecular weight distribution PDI = 1.01. The number average molecular weight was determined by gel permeation chromatography, Agilent 1260 Infinity, THF as solvent, flow rate 1 mL min -1 , test temperature 40℃.

[0061] Example 12: Polymerization of ε-caprolactone catalyzed by catalyst Al1 and benzyl alcohol

[0062] In a Schlenk bottle, under anhydrous and oxygen-free conditions, add 0.228g of ε-caprolactone, add 2.1μL of benzyl alcohol (20μmol), and 20μmol of complex Al1 (9.4mg) dissolved in 2mL TOL, and add it to the Schlenk bottle with a syringe to initiate polymerization. Control the reaction temperature at 90℃ for 5min, add 1mL of 5% acetic acid methanol solution, pour it into methanol to precipitate the polymer, filter it and vacuum dry it for 24 hours to obtain polycaprolactone. Conversion rate: >99%. The number average molecular weight M of the polycaprolactone is n :1.01×10 4 g / mol, molecular weight distribution PDI = 1.09. The number average molecular weight was determined by gel permeation chromatography, Agilent 1260 Infinity, THF as solvent, flow rate 1 mL min -1 , test temperature 40℃.

[0063] Example 13: Polymerization of ε-caprolactone catalyzed by catalyst Al1 and benzyl alcohol

[0064] In a Schlenk bottle, under anhydrous and oxygen-free conditions, add 0.228g of ε-caprolactone, add 2.1μL of benzyl alcohol (20μmol), and 20μmol of complex Al1 (9.4mg) dissolved in 2mL TOL, and add it to the Schlenk bottle with a syringe to initiate polymerization. Control the reaction temperature at 110℃ for 5min, add 1mL of 5% acetic acid methanol solution, pour it into methanol to precipitate the polymer, filter it and vacuum dry it for 24 hours to obtain polycaprolactone. Conversion rate: >99%. The number average molecular weight M of the polycaprolactone is n :9.8×10 3g / mol, molecular weight distribution PDI = 1.34. The number average molecular weight was determined by gel permeation chromatography, Agilent 1260 Infinity, THF as solvent, flow rate 1 mL min -1 , test temperature 40℃.

[0065] Example 14: Polymerization of ε-caprolactone catalyzed by catalyst Al1 and benzyl alcohol

[0066] In two Schlenk bottles, under anhydrous and oxygen-free conditions, add 0.228g of ε-caprolactone, 20μmol of complex Al1 (9.4mg) and 2.1μL of benzyl alcohol (20μmol) dissolved in 2mL TOL, and add them to Schlenk bottle No. 1 with a syringe to initiate polymerization. Control the reaction temperature at 90°C for 5min, add 2mL TOL to Schlenk bottle No. 2, and transfer the solution to Schlenk bottle No. 1 with a syringe to continue the reaction for 5min. Add 1mL of 5% acetic acid methanol solution, pour it into methanol to precipitate the polymer, filter it and vacuum dry it for 24 hours to obtain polycaprolactone. Conversion rate: >99%. The number average molecular weight M of the polycaprolactone is n :2.10×10 4 g / mol, molecular weight distribution PDI = 1.08. The number average molecular weight was determined by gel permeation chromatography, Agilent 1260 Infinity, THF as solvent, flow rate 1 mL min -1 , test temperature 40℃.

[0067] Example 15: Polymerization of ε-caprolactone catalyzed by catalyst Al1 and benzyl alcohol

[0068] In a Schlenk bottle, under anhydrous and oxygen-free conditions, add 0.457g of ε-caprolactone, 2.1μL of benzyl alcohol (20μmol), 2mL of TOL, 20μmol of complex Al1 (9.4mg) dissolved in 2mL of TOL, and added to the Schlenk bottle with a syringe to initiate polymerization. Control the reaction temperature at 90°C for 5min, add 1mL of 5% acetic acid methanol solution, pour into methanol to precipitate the polymer, filter and vacuum dry for 24 hours to obtain polycaprolactone. Conversion rate: >99%. The number average molecular weight M of the polycaprolactone is n :2.04×10 4 g / mol, molecular weight distribution PDI = 1.11. The number average molecular weight was determined by gel permeation chromatography, Agilent 1260 Infinity, THF as solvent, flow rate 1 mL min -1 , test temperature 40℃.

[0069] Example 16: Polymerization of ε-caprolactone catalyzed by catalyst Al1 and benzyl alcohol

[0070] In a Schlenk bottle, under anhydrous and oxygen-free conditions, add 1.14g of ε-caprolactone, 2.1μL of benzyl alcohol (20μmol), 7mL of TOL, 20μmol of complex Al1 (9.4mg) dissolved in 2mL of TOL, and added to the Schlenk bottle with a syringe to initiate polymerization. Control the reaction temperature at 90°C for 5min, add 1mL of 5% acetic acid methanol solution, pour into methanol to precipitate the polymer, filter and vacuum dry for 24 hours to obtain polycaprolactone. Conversion rate: 91%. The number average molecular weight M of the polycaprolactone is n :4.51×10 4 g / mol, molecular weight distribution PDI = 1.04. The number average molecular weight was determined by gel permeation chromatography, Agilent 1260 Infinity, THF as solvent, flow rate 1 mL min -1 , test temperature 40℃.

[0071] Example 17: Polymerization of ε-caprolactone catalyzed by catalyst Al1 and benzyl alcohol

[0072] In a Schlenk bottle, under anhydrous and oxygen-free conditions, add 2.28g of ε-caprolactone, 2.1μL of benzyl alcohol (20μmol), 16mL of TOL, 20μmol of complex Al1 (9.4mg) dissolved in 2mL of TOL, and added to the Schlenk bottle with a syringe to initiate polymerization. Control the reaction temperature at 90°C for 10min, add 1mL of 5% acetic acid methanol solution, pour into methanol to precipitate the polymer, filter and vacuum dry for 24 hours to obtain polycaprolactone. Conversion rate: 91%. The number average molecular weight M of the polycaprolactone is n :8.25×10 4 g / mol, molecular weight distribution PDI = 1.05. The number average molecular weight was determined by gel permeation chromatography, Agilent 1260 Infinity, THF as solvent, flow rate 1 mL min -1 , test temperature 40℃.

[0073] Example 18: Polymerization of ε-caprolactone catalyzed by catalyst Al1 and benzyl alcohol

[0074] In a Schlenk bottle, under anhydrous and oxygen-free conditions, add 4.57g of ε-caprolactone, 2.1μL of benzyl alcohol (20μmol), 34mL of TOL, 20μmol of complex Al1 (9.4mg) dissolved in 2mL of TOL, and added to the Schlenk bottle with a syringe to initiate polymerization. Control the reaction temperature at 90°C for 20min, add 1mL of 5% acetic acid methanol solution, pour into methanol to precipitate the polymer, filter and vacuum dry for 24 hours to obtain polycaprolactone. Conversion rate: 82%. The number average molecular weight M of the polycaprolactone is n :1.29×10 5 g / mol, molecular weight distribution PDI = 1.16. The number average molecular weight was determined by gel permeation chromatography, Agilent 1260 Infinity, THF as solvent, flow rate 1 mL min -1 , test temperature 40℃.

[0075] Example 19: Polymerization of ε-caprolactone catalyzed by catalyst Al1 and benzyl alcohol

[0076] In a Schlenk bottle, under anhydrous and oxygen-free conditions, add 0.228g of ε-caprolactone, add 4.2μL of benzyl alcohol (40μmol), and dissolve 20μmol of complex Al1 (9.4mg) in 2mL TOL. Use a syringe to add it to the Schlenk bottle to initiate polymerization. Control the reaction temperature at 90℃ for 5min, add 1mL of 5% acetic acid methanol solution, pour it into methanol to precipitate the polymer, filter it, and vacuum dry it for 24 hours to obtain polycaprolactone. Conversion rate: >99%. The number average molecular weight M of the polycaprolactone is n :5.9×10 3 g / mol, molecular weight distribution PDI = 1.11. The number average molecular weight was determined by gel permeation chromatography, Agilent 1260 Infinity, THF as solvent, flow rate 1 mL min -1 , test temperature 40℃.

[0077] Example 20: Polymerization of ε-caprolactone catalyzed by catalyst Al1 and benzyl alcohol

[0078] In a Schlenk bottle, under anhydrous and oxygen-free conditions, add 2.28g of ε-caprolactone, 21μL of benzyl alcohol (0.2mmol), 16mL of TOL, 20μmol of complex Al1 (9.4mg) dissolved in 2mL of TOL, and added to the Schlenk bottle with a syringe to initiate polymerization. Control the reaction temperature at 90°C for 30min, add 1mL of 5% acetic acid methanol solution, pour into methanol to precipitate the polymer, filter and vacuum dry for 24 hours to obtain polycaprolactone. Conversion rate: >99%. The number average molecular weight M of the polycaprolactone is n:9.6×10 3 g / mol, molecular weight distribution PDI = 1.12. The number average molecular weight was determined by gel permeation chromatography, Agilent 1260 Infinity, THF as solvent, flow rate 1 mL min -1 , test temperature 40℃.

[0079] Example 21: Polymerization of ε-caprolactone catalyzed by catalyst Al1 and benzyl alcohol

[0080] In a Schlenk bottle, under anhydrous and oxygen-free conditions, add 4.57g of ε-caprolactone, 42μL of benzyl alcohol (0.4mmol), 34mL of TOL, 20μmol of complex Al1 (9.4mg) dissolved in 2mL of TOL, and added to the Schlenk bottle with a syringe to initiate polymerization. Control the reaction temperature at 90°C for 120min, add 1mL of 5% acetic acid methanol solution, pour into methanol to precipitate the polymer, filter and vacuum dry for 24 hours to obtain polycaprolactone. Conversion rate: >99%. The number average molecular weight M of the polycaprolactone is n :1.15×10 4 g / mol, molecular weight distribution PDI = 1.16. The number average molecular weight was determined by gel permeation chromatography, Agilent 1260 Infinity, THF as solvent, flow rate 1 mL min -1 , test temperature 40℃.

[0081] Example 22: Polymerization of ε-caprolactone catalyzed by catalyst Al2 and benzyl alcohol

[0082] In a Schlenk bottle, under anhydrous and oxygen-free conditions, add 1.14g of ε-caprolactone, 2.1μL of benzyl alcohol (20μmol), 7mL of TOL, 20μmol of complex Al2 (8.1mg) dissolved in 2mL of TOL, and added to the Schlenk bottle with a syringe to initiate polymerization. Control the reaction temperature at 90℃ for 5min, add 1mL of 5% acetic acid methanol solution, pour into methanol to precipitate the polymer, filter and vacuum dry for 24 hours to obtain polycaprolactone. Conversion rate: 95%. The number average molecular weight M of the polycaprolactone is n :4.34×10 4 g / mol, molecular weight distribution PDI = 1.03. The number average molecular weight was determined by gel permeation chromatography, Agilent 1260 Infinity, THF as solvent, flow rate 1 mL min -1 , test temperature 40℃.

[0083] Example 23: Polymerization of ε-caprolactone catalyzed by catalyst Al3 and benzyl alcohol

[0084] In a Schlenk bottle, under anhydrous and oxygen-free conditions, add 1.14g of ε-caprolactone, 2.1μL of benzyl alcohol (20μmol), 7mL of TOL, 20μmol of complex Al3 (8.5mg) dissolved in 2mL of TOL, and added to the Schlenk bottle with a syringe to initiate polymerization. Control the reaction temperature at 90℃ for 5min, add 1mL of 5% acetic acid methanol solution, pour into methanol to precipitate the polymer, filter and vacuum dry for 24 hours to obtain polycaprolactone. Conversion rate: 91%. The number average molecular weight M of the polycaprolactone is n :5.18×10 4 g / mol, molecular weight distribution PDI = 1.08. The number average molecular weight was determined by gel permeation chromatography, Agilent 1260 Infinity, THF as solvent, flow rate 1 mL min -1 , test temperature 40℃.

[0085] Example 24: Polymerization of ε-caprolactone catalyzed by catalyst Al4 and benzyl alcohol

[0086] In a Schlenk bottle, under anhydrous and oxygen-free conditions, add 1.14g of ε-caprolactone, 2.1μL of benzyl alcohol (20μmol), 7mL of TOL, 20μmol of complex Al4 (9.1mg) dissolved in 2mL of TOL, and added to the Schlenk bottle with a syringe to initiate polymerization. Control the reaction temperature at 90°C for 5min, add 1mL of 5% acetic acid methanol solution, pour into methanol to precipitate the polymer, filter and vacuum dry for 24 hours to obtain polycaprolactone. Conversion rate: 83%. The number average molecular weight M of the polycaprolactone is n :4.60×10 4 g / mol, molecular weight distribution PDI = 1.06. The number average molecular weight was determined by gel permeation chromatography, Agilent 1260 Infinity, THF as solvent, flow rate 1 mL min -1 , test temperature 40℃.

[0087] Example 25: Polymerization of ε-caprolactone catalyzed by catalyst Al5 and benzyl alcohol

[0088] In a Schlenk bottle, under anhydrous and oxygen-free conditions, add 1.14g of ε-caprolactone, 2.1μL of benzyl alcohol (20μmol), 7mL of TOL, 20μmol of complex Al5 (14.3mg) dissolved in 2mL of TOL, and added to the Schlenk bottle with a syringe to initiate polymerization. Control the reaction temperature at 90°C for 5min, add 1mL of 5% acetic acid methanol solution, pour into methanol to precipitate the polymer, filter and vacuum dry for 24 hours to obtain polycaprolactone. Conversion rate: 84%. The number average molecular weight M of the polycaprolactone isn :4.24×10 4 g / mol, molecular weight distribution PDI = 1.06. The number average molecular weight was determined by gel permeation chromatography, Agilent 1260 Infinity, THF as solvent, flow rate 1 mL min -1 , test temperature 40℃.

[0089] Example 26: Polymerization of rac-lactide catalyzed by compound A11 and benzyl alcohol

[0090] In a Schlenk bottle, under anhydrous and oxygen-free conditions, add 0.288g of rac-lactide, add 2.1μL of benzyl alcohol (20μmol), and dissolve 20μmol of complex Al1 (9.4mg) in 2mL TOL. Use a syringe to add it to the Schlenk bottle to initiate polymerization. Control the reaction temperature at 110℃ for 6h, add 1mL of 5% acetic acid methanol solution, pour it into methanol to precipitate the polymer, filter it, and vacuum dry it for 24 hours to obtain polylactide. Conversion rate: >99%. The number average molecular weight M of the polylactide is n :1.26×10 4 g / mol, molecular weight distribution PDI = 1.11. The number average molecular weight was determined by gel permeation chromatography, Agilent 1260 Infinity, THF as solvent, flow rate 1 mL min -1 , test temperature 40℃.

[0091] Example 27: Polymerization of ε-caprolactone and rac-lactide catalyzed by compound A11 and benzyl alcohol

[0092] In a Schlenk bottle, under anhydrous and oxygen-free conditions, add 0.228g of ε-caprolactone and 0.288g of rac-lactide, add 2.1μL of benzyl alcohol (20μmol), and 20μmol of complex Al1 (9.4mg) dissolved in 2mL TOL, and add it to the Schlenk bottle with a syringe to initiate polymerization. Control the reaction temperature at 110℃ for 6h, add 1mL of 5% acetic acid methanol solution, pour it into methanol to precipitate the polymer, filter it and vacuum dry it for 24 hours to obtain polylactide. Conversion rate: ε-caprolactone is 36%, rac-lactide is>99%. The number average molecular weight of the polymer is M n :1.54×10 4 g / mol, molecular weight distribution PDI = 1.14. The number average molecular weight was determined by gel permeation chromatography, Agilent 1260 Infinity, THF as solvent, flow rate 1 mL min -1 , test temperature 40℃.

Claims

1. An aminoquinoline metal aluminum catalyst, the structure of which is shown in formula (I): in, R 1 is selected from bromine, methyl, chlorine; R 2 is selected from isopropyl, chloro, diphenylmethyl; R 3 Selected from hydrogen and isopropyl.

2. The method for preparing the aminoquinoline metal aluminum catalyst according to claim 1, comprising the following steps: in a nitrogen atmosphere, 8-R 1 -2-Formaldehyde-quinoline and substituted aniline are mixed in a molar ratio of 0.8-1.2:0.8-1.5, and a catalytic amount of 5-20 mg of p-toluenesulfonic acid is added, and the mixture is stirred and reacted for 12-24 hours in a mixed solvent of methanol and dichloromethane (the volume ratio of methanol to dichloromethane is 1:1-5); the mixed solvent is removed under reduced pressure, and the obtained product is washed with ethanol and filtered and dried to obtain an organic ligand; under a nitrogen atmosphere, the organic ligand is dissolved in an anhydrous solvent, and 1.0-1.5 molar equivalents of trimethylaluminum are added, and the mixture is stirred and reacted at room temperature for 12-24 hours; the solvent is removed under reduced pressure, and the mixture is washed with a poor solvent to obtain an aminoquinoline metal aluminum catalyst.

3. The method according to claim 2, wherein the anhydrous solvent used in the reaction is selected from benzene, toluene, xylene, and tetrahydrofuran; and the poor solvent is selected from n-hexane, n-pentane, n-heptane, and cyclohexane.

4. The use of the aminoquinoline metal aluminum catalyst according to claim 1, characterized in that: Used to catalyze the ring-opening polymerization reaction of lactones, wherein the lactones include one or more of caprolactone, lactide, glycolide, butyrolactone, valerolactone, enantholactone and octanolactone.

5. The use according to claim 4, characterized in that: The aminoquinoline metal aluminum catalyst described in claim 1 is used as a catalyst to catalyze the polymerization of caprolactone at 0 to 110° C., wherein the molar ratio of the catalyst to caprolactone during the polymerization is 1:10 to 10,000; the polymerization time is 5 minutes to 12 hours; and the polymerization solvent is selected from benzene, toluene, n-hexane, tetrahydrofuran and dichloromethane.

6. The use according to claim 4, characterized in that: When initiating polymerization, methanol, ethanol, isopropanol, n-butanol, ethylene glycol, propylene glycol, and benzyl alcohol can be added as initiators, and the molar ratio of the initiator to the catalyst aluminum metal is 0 to 100:1.

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