CN101538361A - Cyclic esters compound polymerization catalyst, preparation method and application thereof - Google Patents

Abstract

The invention belongs to a cyclic ester compound polymerization catalyst, a preparation method and usage. The catalyst for the polymerization of cyclic ester compounds has a structure of bis(bistrimethylsilylamino)zinc (Zn[N(SiMe ₃ ) ₂ ] ₂ ). Bis(bistrimethylsilylamino)zinc was synthesized by two-step reaction using hexamethyldisilazylamine as substrate, butyl lithium and anhydrous zinc chloride as reactants, and using it as catalyst, a Alcohols or phenolic compounds are used as initiators, and L-lactide, caprolactone, and cyclic carbonates are used as monomers, and solution polymerization, bulk polymerization or block copolymerization is adopted, and the reaction temperature is 0～ Stir at 210°C for 5 minutes to 48 hours to prepare polyester homopolymers and copolymers. This method has a fast polymerization reaction rate and a high monomer conversion rate. The obtained polyester has a number average molecular weight of 10,000 to 100,000 and a molecular weight distribution of 1.1 to 1.7. It has high stereoregularity and melting point, and is suitable for multiple specifications. Production and application of high-performance polyester materials.

Description

Cyclic ester compound polymerization catalyst, preparation method and application

technical field

The invention relates to a cyclic ester compound polymerization catalyst, a preparation method and an application.

Background technique

Polyester compounds (such as L-polylactic acid, polycaprolactone, polycarbonate) are widely used in medical and pharmaceutical fields due to their good biocompatibility and degradability. Their products such as surgical sutures, bone nails, Drug sustained-release capsules, etc.; L-polylactic acid is widely used in daily necessities because of its good mechanical properties and is considered to be an environmentally friendly substitute for traditional polyolefin materials.

The preparation of polyester compounds is mostly carried out by ring-opening polymerization of cyclic monomers initiated by initiators. Different initiation systems and different polymerization conditions will have a significant impact on the structure and properties of polymers. Most initiators initiate the polymerization of cyclic ester monomers under high temperature conditions, and this polymerization process has the disadvantages of high energy consumption and easy occurrence of racemization reactions at high temperatures (Macromolecules 2001, 34, 3863-3868), The resulting polymer has a low melting point and poor mechanical properties. At the same time, many initiators themselves have high biological toxicity, and the initiators remain in the polymer after polymerization and are difficult to completely remove, which limits the application of this polymer in the medical and pharmaceutical fields. Therefore, adopting a new initiation system and changing the polymerization conditions are necessary ways to reduce production energy consumption and improve polymer properties.

Contents of the invention

In order to solve the problems in the prior art, the invention provides a cyclic ester compound polymerization catalyst, a preparation method and an application.

The cyclic ester compound polymerization catalyst provided by the present invention is bis(bistrimethylsilylamino)zinc, and its chemical formula is (Zn[N(SiMe ₃ ) ₂ ] ₂ );

The preparation method of the cyclic ester compound polymerization catalyst bis(bistrimethylsilylamino)zinc provided by the present invention uses hexamethyldisilazylamine as the reaction substrate, and reacts with butyllithium and anhydrous zinc chloride The product is obtained in two steps in the presence of an organic solvent; its reaction steps and conditions are as follows:

Step 1) Hexamethyldisilazylamine and butyllithium are mixed in a sealed reactor to react to generate lithium hexamethyldisilazide; the molar ratio of hexamethyldisilazylamine to butyllithium is 1: 1～1.5, the reaction temperature is -10～20℃, and the reaction time is 10～10 hours;

Step 2) Mix the lithium hexamethyldisilazide obtained in step 1) with anhydrous zinc chloride in a sealed reactor, and add an organic solvent to react to form bis(bistrimethylsilylamino)zinc ; The molar ratio of lithium hexamethyldisilazide to anhydrous zinc chloride is 2 to 3:1, the reaction temperature is 0 to 100°C, and the reaction time is 10 minutes to 10 hours;

The organic solvent used is one of ether, toluene and tetrahydrofuran, and the amount of solvent used is 1 to 4 times that of hexamethyldisilazyl ammonia;

The cyclic ester compound polymerization catalyst provided by the invention is used for synthesizing polyester compounds.

Two (bistrimethylsilylamino) zinc provided by the invention is that the steps and conditions of the method for the synthesis of polyester compounds as a catalyst are as follows:

Using bis(bistrimethylsilylamino)zinc as catalyst, alcohol or phenolic compound as initiator, L-lactide, caprolactone or cyclic carbonate as monomer, adopt solution polymerization and bulk polymerization or block copolymerization method to prepare polyester homopolymer or copolymer;

The alcohol compounds used are methanol, ethanol, propanol, isopropanol, butanol, isobutanol, ethylene glycol, butanediol, glycerol and polyethylene oxide with a molecular weight of 750Da to 5000Da containing terminal hydroxyl groups one of

The phenolic compound used is one of phenol, cresol, catechol, resorcinol and hydroquinone;

The cyclic ester monomer used is L-lactide, caprolactone or cyclic carbonate; Among them, the cyclic carbonate is preferably 5-methyl-5-propargyloxycarbonyl-1,3-dioxane- 2-Keto, 5-methyl-5-benzyloxycarbonyl-1,3-dioxane-2-one, 2-benzyloxyamidotrimethylene carbonate and 2-methyl-2-benzyloxymethanol A kind of in base-trimethylene carbonate;

1) The solution polymerization reaction method is as follows: use toluene or tetrahydrofuran as solvent, add monomer, catalyst and initiator in sequence in the sealed reactor, the mass ratio of solvent to monomer is 5 ~ 50: 1, the polymerization temperature In the range of 0-120°C, the reaction time is 5 minutes to 10 hours; the monomer conversion rate of the obtained polyester is 100%, the number-average molecular weight of the polyester is in the range of 5000-40000Da, and the molecular weight distribution is 1.1-1.4 , wherein the melting point of poly-L-lactide is in the range of 166°C to 173°C;

2) The bulk polymerization method is as follows: add monomers, catalysts and initiators in sequence in a sealed reactor, the polymerization temperature is 110°C to 210°C, and the reaction time is 24 to 48 hours; the obtained polyester The monomer conversion rate is 100%, the number-average molecular weight of polyester is in the range of 10000-100000Da, the molecular weight distribution is 1.5-1.7, and the melting point of polylactide is in the range of 166°C-174°C;

3) The reaction method adopting block copolymerization is as follows: with toluene or tetrahydrofuran as a solvent, L-lactide or caprolactone as the first monomer, the mass ratio of the solvent to the first monomer is 5 to 50: 1, in The catalyst and initiator are sequentially added into the sealed reactor, the polymerization reaction temperature is 0°C to 120°C, and the reaction is 5 minutes to 10 hours, and then the cyclic carbonate is added as the second monomer, and the second monomer and the first monomer The molar ratio of the monomer is 0-1:1, and the reaction is continued for 1-10 hours at a polymerization reaction temperature of 0°C-120°C; in the obtained polyester block copolymer, the conversion rate of the first monomer is 100%. , the conversion rate of the second monomer is 90-100%, the number-average molecular weight of the polyester is in the range of 5000-40000 Da, and the molecular weight distribution is 1.4-1.6.

Beneficial effects: the invention belongs to the polymerization catalyst of cyclic ester compounds, its preparation method and application. With hexamethyldisilazyl ammonia as substrate, butyllithium and anhydrous zinc chloride are reactants to synthesize cyclic ester compound polymerization catalyst bis(bistrimethylsilylamino)zinc by two-step reaction; reaction steps Less, easy to operate, and high reaction efficiency (total reaction yield of 76% to 90%).

Using the above-mentioned bis(bistrimethylsilylamino)zinc as a catalyst and an alcohol or phenolic compound as an initiator, a polymer with a molecular weight of about 10,000 can be prepared by polymerization at room temperature. The reaction energy consumption is low, and the polymerization The reaction rate is high, detected by high performance liquid chromatography (HPLC) and gel permeation chromatography (GPC), after 30 minutes of reaction, the polymer conversion rate can reach 100%, and the obtained polymer molecular weight distribution is narrow (polymerization obtained by solution polymerization) The molecular weight distribution of the polymer is below 1.4), and the thermal performance of the polymer is good (detected by differential thermal scanning analysis (DSC), the melting point of the polymer is in the range of 166° C. to 174° C.).

This method can also be used to realize the normal temperature copolymerization of lactide and cyclic carbonate, the polymerization activity is high (the conversion rate of the two copolymer monomers is close to 100%), and the obtained copolymer molecular weight distribution is still It can be maintained at a narrow level (GPC test results show that the molecular weight distribution of the copolymer is in the range of 1.4 to 1.6.

Since the prepared polymer contains a large number of biologically reactive groups, which can undergo bonding reactions with a large number of small molecular compounds, the application of this polymer in the later medical and pharmaceutical fields has broad prospects.

This method is also suitable for high-temperature solution polymerization and bulk polymerization of cyclic monomers to prepare high-molecular-weight polymers (the highest molecular weight can reach 100,000 Da), and the prepared polymers do not produce mesization and have good thermal properties. (Detected by differential thermal scanning analysis (DSC), the melting point of the polymer is in the range of 166° C. to 174° C.).

Detailed ways

Embodiment 1: the synthesis of two (bistrimethylsilyl amino) zinc

Add 10.5ml of hexamethyldisilazylamine into the three-necked flask, slowly drop in 20ml of LiBu (2.5N hexane solution) under the action of an ice-salt bath (-10°C), stir and react for 10 hours, and pour into the three-necked flask after the reaction Add 3.46g of anhydrous ZnCl ₂ , and add 30ml of anhydrous ether, react at 0°C for 10 hours, after the reaction, drain the excess hexamethyldisilazyl ammonia and solvent, and then reduce the pressure at 130°C The product was isolated by distillation in an overall reaction yield of 82%.

Embodiment 2: the synthesis of two (bistrimethylsilyl amino) zinc

Add 12ml of hexamethyldisilazylamine into the three-necked flask, slowly add 20ml of LiBu (2.5N hexane solution) dropwise at 0°C, stir and react for 3 hours, and add 3.46g of anhydrous _ZnCl2 to the three-necked flask after the reaction , and added 30ml of anhydrous tetrahydrofuran, and reacted at 70°C for 4 hours. After the reaction, the excess hexamethyldisilazylammonium and solvent were drained, and then the product was separated by vacuum distillation at 130°C. The total reaction The yield was 90%.

Embodiment 3: the synthesis of two (bistrimethylsilyl amino) zinc

Add 15ml of hexamethyldisilazylamine into the three-necked flask, slowly add 20ml of LiBu (2.5N hexane solution) dropwise at 20°C, stir and react for 10 minutes, and add 3.46g of anhydrous _ZnCl2 to the three-necked flask after the reaction , and added 60ml of anhydrous toluene, and reacted at 100°C for 10 minutes. After the reaction, the excess hexamethyldisilazylammonium and solvent were drained, and then the product was separated by vacuum distillation at 130°C. The total reaction The yield was 76%.

Example 4: Solution Polymerization of Lactide

Put 1.0 g of L-lactide into a flame-baked reaction bottle, ventilate it with nitrogen three times, seal it, add 10 ml of dry tetrahydrofuran with a syringe, and after dissolving, add 10 μl of isopropanol and 26.4 μl of bis(bistri Methylsilylamino) zinc, stirred at room temperature for 40 minutes. The reactant was settled with excess methanol, filtered to obtain a white solid, and vacuum-dried at 40° C. for 24 hours to obtain a polylactic acid product with a molecular weight of 8800 and a molecular weight distribution of 1.21.

Example 5: Solution Polymerization of Lactide

Put 1.78g of L-lactide into a flame-baked reaction bottle, ventilate it with nitrogen three times, seal it and add 10ml of dry tetrahydrofuran with a syringe. After dissolving, add 10μl of methanol and 50μl of bis(bistrimethyl Silicon amino) zinc, reacted at 0°C for 50 minutes with stirring. The reactant was settled with excess methanol, filtered to obtain a white solid, and vacuum-dried at 40° C. for 24 hours to obtain a polylactic acid product with a molecular weight of 9000 and a molecular weight distribution of 1.18.

Example 6: Solution Polymerization of Lactide

Put 5.18g of L-lactide into a flame-baked reaction flask, ventilate it with nitrogen three times, add 10ml of dry tetrahydrofuran with a syringe after sealing, and after dissolving, add 10μl of ethylene glycol and 72.5μl of bis(bistri Methylsilylamino) zinc, stirred at room temperature for 45 minutes. The reactant was settled with excess methanol, filtered to obtain a white solid, and vacuum-dried at 40° C. for 24 hours to obtain a polylactic acid product with a molecular weight of 9300 and a molecular weight distribution of 1.24.

Example 7: Solution Polymerization of Caprolactone

Put 3.4g of caprolactone into the flame-baked reaction bottle, ventilate it with nitrogen three times, add 10ml of dry tetrahydrofuran with a syringe after sealing, after dissolving, add 10μl of butanediol and 47.9μl of bis(bistrimethyl Silylamino) zinc, stirred at room temperature for 60 minutes. The reactant was settled with excess methanol, filtered to obtain a white solid, and vacuum-dried at 40° C. for 24 hours to obtain polycaprolactone product with a molecular weight of 8900 and a molecular weight distribution of 1.19.

Example 8: Solution Polymerization of Lactide

Put 5.9g of L-lactide into the flame-baked reaction bottle, ventilate it with nitrogen three times, add 10ml of dry tetrahydrofuran with a syringe after sealing, and after dissolving, add 10μl of glycerol and 50μl of bis(bistrimethyl Silylamino) zinc, stirred at room temperature for 5 minutes. The reactant was settled with excess methanol, filtered to obtain a white solid, and vacuum-dried at 40° C. for 24 hours to obtain a polylactic acid product with a molecular weight of 9400 and a molecular weight distribution of 1.25.

Example 9: Solution Polymerization of Lactide

Put 1.0 g of L-lactide into a flame-baked reaction flask, ventilate with nitrogen three times, add 10 ml of phenol in tetrahydrofuran (6.53×10 ^-6 mol/ml), dissolve and add 26.4 μl of bis (Bistrimethylsilylamino)zinc, stirred at room temperature for 2 hours. The reactant was settled with excess methanol, filtered to obtain a white solid, and vacuum-dried at 40° C. for 24 hours to obtain a polylactic acid product with a molecular weight of 5000 and a molecular weight distribution of 1.23.

Example 10: Solution Polymerization of Lactide

Put 6.23g of L-lactide into a flame-baked reaction bottle, ventilate it with nitrogen three times, seal it and add 60ml of dry toluene with a syringe, after dissolving, add 10μl of isobutanol and 30μl of bis(bistrimethyl Silicon-based amino) zinc, stirred at 90 ° C for 5 hours. The reactant was settled with excess methanol, filtered to obtain a white solid, and vacuum-dried at 40° C. for 24 hours to obtain a polylactic acid product with a molecular weight of 40,000 and a molecular weight distribution of 1.4.

Example 11: High temperature solution polymerization of lactide

Put 6.23g of L-lactide into a flame-baked reaction bottle, ventilate it with nitrogen three times, add 60ml of dry toluene with a syringe after sealing, and after dissolving, add 10μl of n-butanol and 30μl of bis(bistrimethyl Silicon-based amino) zinc, stirred at 120 ° C for 10 hours. The reactant was settled with excess methanol, filtered to obtain a white solid, and vacuum-dried at 40° C. for 24 hours to obtain a polylactic acid product with a molecular weight of 32,000 and a molecular weight distribution of 1.31.

Embodiment 12: bulk polymerization of lactide

Put 12.0g of L-lactide into the reaction flask baked by flame, ventilate with nitrogen three times, add 14mg of o-cresol and 26.4μl of bis(bistrimethylsilylamino)zinc, stir in The reaction was carried out at 210° C. for 48 hours. The reactant was dissolved with a small amount of chloroform and settled with excess methanol to obtain a white solid. Vacuum drying at 40°C for 24 hours yielded a polylactic acid product with a molecular weight of 100,000 and a molecular weight distribution of 1.72.

Example 13: Bulk polymerization of lactide

Put 12.0 g of L-lactide into a flame-baked reaction flask, ventilate with nitrogen three times, add 14 mg of m-cresol and 26.4 μl of bis(bistrimethylsilylamino)zinc, and stir in Reaction at 200°C for 51h. The reactant was dissolved with a small amount of chloroform and settled with excess methanol to obtain a white solid. Vacuum drying at 40°C for 24 hours yielded a polylactic acid product with a molecular weight of 98,000 and a molecular weight distribution of 1.74.

Example 14: Bulk polymerization of lactide

Put 12.0g of L-lactide into the reaction flask baked by flame, ventilate with nitrogen three times, add 14mg of p-cresol and 26.4μl of bis(bistrimethylsilylamino)zinc, and stir in Reaction at 200°C for 50h. The reactant was dissolved with a small amount of chloroform and settled with excess methanol to obtain a white solid. Vacuum drying at 40°C for 24 hours yielded a polylactic acid product with a molecular weight of 100,000 and a molecular weight distribution of 1.66.

Example 15: Bulk polymerization of lactide

Put 12.0 g of L-lactide into a flame-baked reaction flask, ventilate with nitrogen three times, add 14 mg of catechol and 26.4 μl of bis(bistrimethylsilylamino)zinc, and stir The reaction was carried out at 160° C. for 48 hours. The reactant was dissolved with a small amount of chloroform and settled with excess methanol to obtain a white solid. Vacuum drying at 40°C for 24 hours yielded a polylactic acid product with a molecular weight of 90,000 and a molecular weight distribution of 1.5.

Example 16: Bulk polymerization of lactide

Put 12.0 g of L-lactide into a flame-baked reaction flask, ventilate with nitrogen three times, add 14 mg of resorcinol and 26.4 μl of bis(bistrimethylsilylamino)zinc, and stir The reaction was carried out at 160° C. for 48 hours. The reactant was dissolved with a small amount of chloroform and settled with excess methanol to obtain a white solid. Vacuum drying at 40°C for 24 hours yielded a polylactic acid product with a molecular weight of 85,000 and a molecular weight distribution of 1.65.

Example 17: Bulk polymerization of lactide

Put 12.0 g of L-lactide into a flame-baked reaction flask, ventilate with nitrogen three times, add 14 mg of hydroquinone and 26.4 μl of bis(bistrimethylsilylamino)zinc, and stir The reaction was carried out at 110° C. for 24 hours. The reactant was dissolved with a small amount of chloroform and settled with excess methanol to obtain a white solid. Vacuum drying at 40°C for 24 hours yielded a polylactic acid product with a molecular weight of 10,000 and a molecular weight distribution of 1.67.

Example 18: Block copolymerization of lactide and 5-methyl-5-benzyloxycarbonyl-1,3-dioxane-2-one

Put 0.5g of L-lactide into the flame-baked reaction bottle, ventilate it with nitrogen three times, add 2.5ml of dry toluene with a syringe after sealing, add 10μl of isopropanol and 26.4μl of bis(bistrimethyl Silicon amino) zinc, reacted for 5 minutes under stirring at 0°C, then added 0.6g of 5-methyl-5-benzyloxycarbonyl-1,3-dioxane-2-one into the reaction flask, and continued to Stir at low temperature for 1 hour, the reactant was precipitated with methanol and filtered to obtain a white solid, which was vacuum-dried at 40°C to obtain a block copolymer. The conversion rate of lactide was 100%, and the conversion rate of carbonate ester was 90%. The copolymer The molecular weight is 10000 and the molecular weight distribution is 1.4.

Example 19: Block copolymerization of lactide and 5-methyl-5-propargyloxycarbonyl-1,3-dioxane-2-one

Put 0.5g of L-lactide into the flame-baked reaction bottle, ventilate with nitrogen three times, seal it, add 25ml of dry tetrahydrofuran with a syringe, add 2.5μl of isopropanol and 6.7μl of bis(bistrimethyl Silicon-based amino) zinc, reacted for 40 minutes under stirring at room temperature, then added 0.6g 5-methyl-5-propargyloxycarbonyl-1,3-dioxane-2-one in the reaction flask, and continued to Stirring for 10 hours, the reactant was settled with methanol and filtered to obtain a white solid, which was vacuum-dried at 40°C to obtain a block copolymer. The conversion rate of lactide was 100%, the conversion rate of carbonate was 100%, and the molecular weight of the copolymer was The molecular weight distribution is 1.6 for 40000.

Example 20: Block copolymerization of lactide and 2-benzyloxyamidotrimethylene carbonate

Put 0.5g of L-lactide into the flame-baked reaction bottle, ventilate with nitrogen three times, seal it, add 5ml of dry toluene with a syringe, add 10μl of isopropanol and 26.4μl of bis(bistrimethylsilyl Amino) zinc, reacted for 10 hours under stirring at 120°C, then added 0.6g of 2-benzyloxyamidotrimethylene carbonate to the reaction flask, and continued to stir at 120°C for 1 hour, the reactant was settled with methanol and filtered, A white solid was obtained, which was vacuum-dried at 40° C. to obtain a block copolymer. The conversion rate of lactide was 100%, the conversion rate of carbonate was 100%, the molecular weight of the copolymer was 12000, and the molecular weight distribution was 1.4.

Example 21: Block copolymerization of lactide with 2-methyl-2-benzyloxymethyl-trimethylene carbonate

Put 0.5g of L-lactide into the flame-baked reaction bottle, ventilate with nitrogen three times, seal it, add 5ml of dry toluene with a syringe, add 10μl of isopropanol and 26.4μl of bis(bistrimethylsilyl Amino) zinc, reacted for 40 minutes under stirring at room temperature, then added 0.6g 2-methyl-2-benzyloxymethyl-trimethylene carbonate in the reaction flask, continued to stir at room temperature for 2 hours, and the reactant was washed with methanol After settling and filtering, a white solid was obtained, which was dried under vacuum at 40°C to obtain a block copolymer with a lactide conversion rate of 100%, a carbonate conversion rate of 94%, and a molecular weight of the copolymer of 11,000 and a molecular weight distribution of 1.4.

Claims (5)

1. The catalyst for the polymerization of cyclic ester compounds is bis(bistrimethylsilylamino)zinc, whose chemical formula is (Zn[N(SiMe ₃ ) ₂ ] ₂ ). 2. the preparation method of a kind of cyclic ester compound polymerization catalyst as claimed in claim 1 is characterized in that, with hexamethyldisilazyl ammonia as reaction substrate, with butyllithium and anhydrous zinc chloride as reaction The product is obtained in two steps in the presence of an organic solvent; its reaction steps and conditions are as follows: Step 1) Hexamethyldisilazylamine and butyllithium are mixed in a sealed reactor to react to generate lithium hexamethyldisilazide; the molar ratio of hexamethyldisilazylamine to butyllithium is 1: 1～1.5, the reaction temperature is -10～20℃, and the reaction time is 10～10 hours; Step 2) Mix the lithium hexamethyldisilazide obtained in step 1) with anhydrous zinc chloride in a sealed reactor, and add an organic solvent to react to form bis(bistrimethylsilylamino)zinc ; The molar ratio of lithium hexamethyldisilazide to anhydrous zinc chloride is 2 to 3:1, the reaction temperature is 0 to 100°C, and the reaction time is 10 minutes to 10 hours; The organic solvent used is one of diethyl ether, toluene and tetrahydrofuran, and the amount of the solvent used is 1 to 4 times that of the hexamethyldisilazyl ammonia. 3. the application of a kind of cyclic ester compound polymerization catalyst as claimed in claim 1, is characterized in that, it is used for synthesizing polyester compound. 4. a kind of cyclic ester compound polymerization catalyst as claimed in claim 3 is used for the method for synthetic polyester compound, it is characterized in that step and condition are as follows: Using bis(bistrimethylsilylamino)zinc as catalyst, alcohol or phenolic compound as initiator, L-lactide, caprolactone or cyclic carbonate as monomer, adopt solution polymerization and bulk polymerization or block copolymerization method to prepare polyester homopolymer or copolymer; The alcohol compounds used are methanol, ethanol, propanol, isopropanol, butanol, isobutanol, ethylene glycol, butanediol, glycerol and polyethylene oxide with a molecular weight of 750Da to 5000Da containing terminal hydroxyl groups one of The phenolic compound used is one of phenol, cresol, catechol, resorcinol and hydroquinone; The cyclic ester monomer used is L-lactide, caprolactone or cyclic carbonate; 1) The solution polymerization reaction method is as follows: use toluene or tetrahydrofuran as solvent, add monomer, catalyst and initiator in sequence in the sealed reactor, the mass ratio of solvent to monomer is 5 ~ 50: 1, the polymerization temperature In the range of 0-120°C, the reaction time is 5 minutes to 10 hours; 2) The method of bulk polymerization is as follows: add monomer, catalyst and initiator in sequence in the sealed reactor, the polymerization temperature is 110°C-210°C, and the reaction time is 24-48 hours; 3) The reaction method adopting block copolymerization is as follows: with toluene or tetrahydrofuran as a solvent, L-lactide or caprolactone as the first monomer, the mass ratio of the solvent to the first monomer is 5 to 50: 1, in The catalyst and initiator are sequentially added into the sealed reactor, the polymerization reaction temperature is 0°C to 120°C, and the reaction is 5 minutes to 10 hours, and then the cyclic carbonate is added as the second monomer, and the second monomer and the first monomer The molar ratio of the monomer is 0 to 1:1, and the reaction is continued for 1 to 10 hours at a polymerization reaction temperature in the range of 0°C to 120°C. 5. a kind of cyclic ester compound polymerization catalyst as claimed in claim 4 is used for the method of synthetic polyester compound, it is characterized in that, the cyclic carbonate that adopts is 5-methyl-5-propargyloxycarbonyl- 1,3-dioxane-2-one, 5-methyl-5-benzyloxycarbonyl-1,3-dioxane-2-one, 2-benzyloxyamidotrimethylene carbonate and 2 - One of methyl-2-benzyloxymethyl-trimethylene carbonate.