A diurea compound having an alicyclic structure, a preparation method, a catalyst system and a polymerization method thereof

Abstract

The application belongs to the field of macrolide polymerization, and relates to a diurea compound with an alicyclic structure, a preparation method, a catalyst system and a polymerization method. The structural formula of the diurea compound is as follows: in the formula, R is an alicyclic structure unit with C6-C18, R1 and R2 are each independently selected from at least one of a hydrogen atom, a C1-C20 alkyl group, a C3-C20 cycloalkyl group, a C6-C20 aromatic group and a substituted C6-C20 aromatic group. The application first proposes that a metal-free organic base / diurea catalyst system can be used to open ring polymerize macrolide polymerization and copolymerize macrolide and other cyclic monomers. The catalyst is easy to synthesize, low in cost, free of metal ions, low in polymerization temperature of the system, and mild in polymerization conditions, and can be used for polyhydroxyl prepolymers or block copolyesters of polyurethane, and has wide application and research value.

Description

Technical Field

[0001] This invention belongs to the field of macrocyclic lactone polymerization, specifically, it relates to a diurea compound with an alicyclic structure, its preparation method, catalyst system, and polymerization method. Background Technology

[0002] The aliphatic polyesters obtained from the ring-opening polymerization of macrolides contain long alkyl chain units. The resulting crystal cells are structurally similar to high-density polyethylene (HDPE), thus their mechanical properties are closer to those of polyolefins. The presence of long-chain aliphatic ester bonds in the molecular chain makes them insensitive to hydrolysis, but they can be composted and enzymatically degraded. This property gives long-chain aliphatic polyesters great market potential and application prospects. Due to the lack of ring strain, commonly used metal catalysts for ring-opening polymerization of macrolides, such as stannous octoate and aluminum isopropoxide, cannot catalyze the ring-opening polymerization of macrolides. The ring-opening polymerization of macrolides generally employs enzymatic catalysis. Enzymatic polymerization products are pure because they do not use metal catalysts or other ligands, but the molecular weight is generally low, the polymerization time is long, and it is difficult to control the molecular structure. The cost of enzymes is also relatively high, which is not conducive to large-scale production.

[0003] Anionic polymerization is an effective method for obtaining high molecular weight products through ring-opening polymerization of macrolides. Commonly used catalysts include metal alkoxides (sodium methoxide, potassium tert-butoxide, sodium tert-butoxide, etc.), phosphononitrile bases, and nitrogen heterocyclic compounds (such as triazabicyclodecene, etc.). These catalysts either contain metal ions or are expensive, making it impossible to obtain large-scale, high molecular weight, pure long-chain aliphatic polyesters. Summary of the Invention

[0004] The purpose of this invention is to solve the above-mentioned problems existing in the prior art, and to provide a diurea compound with an alicyclic structure, its preparation method, catalyst system and polymerization method. This invention uses an organic base as the main catalyst and adds a diurea compound with an alicyclic structure as a co-catalyst. It adopts an anionic polymerization method with mild conditions and low cost, and can obtain high molecular weight polymacrolides and copolyesters. This is of great significance for enriching the types of biodegradable materials and developing green chemistry.

[0005] To achieve the above objectives, a first aspect of the present invention provides a diurea compound having an alicyclic structure, the structural formula of which is as follows:

[0006]

[0007] In the formula, R is a C6-C18 alicyclic structural unit, and R1 and R2 are each independently selected from at least one of hydrogen atom, C1-C20 alkyl, C3-C20 cycloalkyl, C6-C20 aromatic group, and substituted C6-C20 aromatic group.

[0008] A second aspect of the present invention provides a method for preparing the aforementioned diurea compound having an alicyclic structure, comprising the following steps:

[0009] Under the presence of solvent and alkali, a diamine compound with an alicyclic structure is reacted with an isocyanate compound to obtain the diurea compound with an alicyclic structure.

[0010] A third aspect of the present invention provides a catalyst system for the anionic polymerization of macrolides, the catalyst system comprising a main catalyst and a co-catalyst;

[0011] The main catalyst is an organic base; the co-catalyst is the diurea compound with an alicyclic structure; the molar ratio of the main catalyst to the co-catalyst is 1:1-3, preferably 1:1.3-2.8, and more preferably 1:1.5-2.6.

[0012] A fourth aspect of the present invention provides a method for anionic polymerization of macrocyclic lactones, comprising the following steps:

[0013] 1) In the presence of an inert solvent, the polymerizable monomer, the initiator and the catalyst system for the anionic polymerization of macrolides are contacted and reacted; the polymerizable monomer is a macrolide or a macrolide and other cyclic monomers.

[0014] (2) The product obtained in step (1) is diluted and dissolved in a good solvent, and then precipitated in a poor solvent to obtain a long-chain aliphatic polyester.

[0015] The present invention has the following beneficial effects:

[0016] This invention is the first to propose the use of a metal-free organic base / diurea catalytic system for ring-opening polymerization of macrolides and copolymerization of macrolides with other cyclic monomers. The catalyst is easy to synthesize, low in cost, and free of metal ions. The system exhibits low polymerization temperature and mild polymerization conditions, making it suitable for polyurethane prepolymers or block copolyesters, and possessing broad applications and research value.

[0017] Other features and advantages of the present invention will be described in detail in the following detailed description section. Detailed Implementation

[0018] The following provides a detailed description of specific embodiments of the present invention. It should be understood that the specific embodiments described herein are for illustrative and explanatory purposes only and are not intended to limit the scope of the invention.

[0019] To achieve the above objectives, a first aspect of the present invention provides a diurea compound having an alicyclic structure, the structural formula of which is as follows:

[0020]

[0021] In the formula, R is a C6-C18 alicyclic structural unit, and R1 and R2 are each independently selected from at least one of hydrogen atom, C1-C20 alkyl, C3-C20 cycloalkyl, C6-C20 aromatic group, and substituted C6-C20 aromatic group.

[0022] According to the present invention, preferably, R is selected from at least one of the structures shown in formula (1) to formula (6);

[0023]

[0024] According to the present invention, preferably, R1 and R2 are each independently selected from at least one of hydrogen atom, C10-C20 alkyl, C6-C16 cycloalkyl, C6-C12 phenyl, substituted C6-C12 phenyl, C7-C12 benzyl, and substituted C7-C12 benzyl; the substituted group is selected from at least one of halogen, alkyl, alkoxy and aryloxy.

[0025] Preferably, R1 and R2 are each independently selected from at least one of phenyl, cyclohexyl, cyclododecyl, adamantyl, m-tolyl, p-tolyl, m-chlorophenyl, p-chlorophenyl, undecyl, dodecyl, tetradecyl, hexadecyl, octadecyl, 3,4-dichlorophenyl, 3,5-dichlorophenyl, 3-chloro-4-methylphenyl, p-isopropylphenyl, p-bromophenyl, 4-(p-chlorophenoxy)-phenyl, benzyl, 2,4-dimethoxybenzyl, 4-chlorobenzyl, 2-methylbenzyl, 3-methylbenzyl, 2-methoxybenzyl, 4-bromobenzyl, 3,4-dimethoxybenzyl, and 4-isobutoxybenzyl.

[0026] A second aspect of the present invention provides a method for preparing the aforementioned diurea compound having an alicyclic structure, comprising the following steps:

[0027] Under the presence of solvent and alkali, a diamine compound with an alicyclic structure is reacted with an isocyanate compound to obtain the diurea compound with an alicyclic structure.

[0028] According to the present invention, preferably, the diamine compound having an alicyclic structure is selected from at least one of 4,4'-diaminodicyclohexylmethane, 1,4-cyclohexanediamine, 1,3-cyclohexanediamine, 1,3-cyclohexanedimethylamine, 1,4-cyclohexanedimethylamine and isophoronediamine.

[0029] According to the present invention, preferably, the isocyanate compound is selected from phenyl isocyanate, cyclohexane isocyanate, cyclododecane isocyanate, adamantane isocyanate, m-toluene isocyanate, p-toluene isocyanate, m-chlorophenyl isocyanate, p-chlorophenyl isocyanate, undecane isocyanate, dodecane isocyanate, tetradecane isocyanate, hexadecane isocyanate, octadecane isocyanate, 3,4-dichlorophenyl isocyanate, 3,5-dichlorophenyl isocyanate, 3-chlorophenyl isocyanate, etc. At least one of 4-methylbenzyl isocyanate, p-isopropylbenzyl isocyanate, p-bromobenzyl isocyanate, 4-(p-chlorophenoxy)-benzyl isocyanate, benzyl isocyanate, 2,4-dimethoxybenzyl isocyanate, 4-chlorobenzyl isocyanate, 2-methylbenzyl isocyanate, 3-methylbenzyl isocyanate, 2-methoxybenzyl isocyanate, 4-bromobenzyl isocyanate, 3,4-dimethoxybenzyl isocyanate, and 4-isobutoxybenzyl isocyanate.

[0030] According to the present invention, preferably, the base is selected from at least one of triethylamine, pyridine and 4-dimethylaminopyridine; the molar ratio of the base to the isocyanate compound is 0.8-2:1, preferably 1-1.5:1.

[0031] According to the present invention, preferably, the solvent is selected from at least one of general polar solvents such as tetrahydrofuran, dichloromethane, trichloromethane, N,N-dimethylformamide, and ethyl acetate.

[0032] According to the present invention, preferably, the reaction conditions include: a temperature of -10 to 50°C, more preferably -5 to 35°C, and a time of 5 to 40 hours, more preferably 10 to 30 hours.

[0033] A third aspect of the present invention provides a catalyst system for the anionic polymerization of macrolides, the catalyst system comprising a main catalyst and a co-catalyst;

[0034] The main catalyst is an organic base; the co-catalyst is the diurea compound with an alicyclic structure; the molar ratio of the main catalyst to the co-catalyst is 1:1-3, preferably 1:1.3-2.8, and more preferably 1:1.5-2.6.

[0035] According to the present invention, preferably, the organic base is a tetra-armed substituted ammonium hydroxide, and more preferably selected from at least one of tetramethylammonium hydroxide, tetrabutylammonium hydroxide and benzyltrimethylammonium hydroxide.

[0036] A fourth aspect of the present invention provides a method for anionic polymerization of macrocyclic lactones, comprising the following steps:

[0037] (1) Under the presence of an inert solvent, the polymerizable monomer, the initiator and the catalyst system for the anionic polymerization of macrolides are contacted and reacted; the polymerizable monomer is a macrolide or a macrolide and other cyclic monomers.

[0038] (2) The product obtained in step (1) is diluted and dissolved in a good solvent, and then precipitated in a poor solvent to obtain a long-chain aliphatic polyester.

[0039] In this invention, the average content of each monomer in the polymer obtained by polymerization can be calculated using 1H NMR results. By using the ratio of the integral of the methylene group bonded to the oxygen atom in the ester bond at chemical shift 4.2 ppm to the integral of the methylene group at chemical shift 1.25-1.4 ppm (or the peak integral at chemical shift 5.2 ppm), and considering the methylene structure in the two monomers, the ratio of the two monomers can be calculated. The specific algorithm is as follows:

[0040] 1. Assume that the macrolide monomer contains n methylene groups, and another monomer is also a lactone monomer with m methylene groups. In the polymer, the molar content of the macrolide is x, and the molar content of the other monomer is y. In 1H NMR, the integral of the methylene group at chemical shift 4.2 ppm connected to the oxygen atom in the ester bond is Δ1, and the integral of the methylene group at chemical shifts 1.25-1.4 ppm is Δ2. Based on the hydrogen atom identification in the spectrum, the equation can be obtained as follows:

[0041] 2x + 2y = Δ1

[0042] 2x(n-4)+2y(m-4)=Δ2

[0043] Solving the equation yields the values ​​of x and y.

[0044] 2. Assume that the macrolide monomer contains n methylene groups, and the other monomer is lactide. In 1H NMR, the integral of the methylene group at chemical shift 4.2 ppm connected to the oxygen atom in the ester bond is Δ1, and the integral of the methylene group at chemical shift 5.2 ppm is Δ2. In the polymer, the molar content of the macrolide is x, and the molar content of the other monomer is y. Then, 2x = Δ1, y = Δ2, and the ratio of the two chain segments in the polymer can be calculated.

[0045] According to the present invention, preferably, in step (1), the macrolide compound is selected from at least one of cyclopentadecanolactone, cyclohexadecanolactone, and cyclododecanelactone; the other cyclic monomers are 4-7 membered cyclic monomers, preferably at least one of acetyllactone, valproic acid lactone, L-lactide, D-lactide, DL-lactide, glycolide, proprolactone, cyclic carbonate, caprolactam, p-oxocyclohexanedione, and morpholinone; preferably, when the polymerizing monomer is a macrolide and other cyclic monomers, the macrolide monomer accounts for 10-90% of the total molar amount of the polymerizing monomers, preferably 15-85%.

[0046] In this invention, the initiator is a compound with an active hydrogen group, such as a small molecule containing hydroxyl groups and functional substituents, such as a monohydric alcohol, dihydric alcohol, or polyhydric alcohol. It can also be an oligomer or macromolecule containing hydroxyl or amino groups, such as polyethylene glycol or other polyethers with terminal or double hydroxyl groups, polypropylene glycol or other polyethers with terminal or double hydroxyl groups, polyesters such as polycaprolactone with single or double hydroxyl groups, and non-carbon backbone polymers such as polydimethylsiloxane with double amino groups. Preferably, it is a compound with hydroxyl and / or amino groups, preferably at least one of benzyl alcohol, 2-phenylethanol, 2,2-diphenylethanol, ethylene glycol, diethylene glycol monomethyl ether, n-propylamine, and hexamethylenediamine. The molar ratio of the polymerizable monomer to the organic base is 5-1500:1, preferably 10-1200:1; the molar ratio of the polymerizable monomer to the active hydrogen group is 5-1500:1, preferably 7-1200:1.

[0047] According to the present invention, preferably, in step (1), the contact reaction is bulk polymerization or solution polymerization.

[0048] According to the present invention, preferably, in step (1), the contact reaction is solution polymerization, and the solvent for solution polymerization is selected from at least one of toluene, xylene, chlorobenzene, dioxane, tetrahydrofuran, dichloromethane and trichloromethane.

[0049] Preferably, the concentration of the polymeric monomer is 10wt-90wt%, more preferably 20-70wt%.

[0050] Preferably, the conditions for the contact reaction include: a polymerization temperature of 20-85℃, more preferably 35-75℃, and a polymerization time of 1-24h, more preferably 1.5-20h.

[0051] According to the present invention, preferably, in step (2), the good solvent is selected from at least one of toluene, chlorobenzene, xylene and trichlorobenzene; the bad solvent is selected from at least one of petroleum ether, methanol, ethanol, n-hexane and cyclohexane.

[0052] According to the present invention, preferably, the long-chain aliphatic polyester has a weight-average molecular weight of 8,000-300,000 and a molecular weight distribution of 1-3.

[0053] The present invention will be further described below with reference to the embodiments, but the scope of the present invention is not limited to these embodiments.

[0054] The molecular weight and molecular weight distribution of the polymer were determined by gel permeation chromatography (GPC) using trichlorobenzene as solvent on a Waters-208 instrument (equipped with a Waters 2410RI detector, flow rate of 1.5 mL / min, 160 °C). The molecular weight was calibrated using monodisperse linear polystyrene standards.

[0055] Nuclear magnetic resonance spectroscopy (¹H NMR): performed on an Agilent 600MHz DD2 NMR spectrometer, using CDCl3 as solvent, at room temperature.

[0056] Example 1

[0057] 1,4-Cyclohexanediamine (4.2 g, 0.02 mol) was dissolved in tetrahydrofuran, and triethylamine (4.1 g, 0.04 mol) was added. The solution was cooled to 0 °C, and a cooled solution of cyclohexane isocyanate (5.24 g, 0.04 mol) dissolved in 10 mL of tetrahydrofuran was added dropwise. The reaction was maintained at 0 °C for 1 h, then heated to room temperature and reacted for 12 h. After the reaction was complete, the mixture was filtered, the precipitate was washed with tetrahydrofuran, and dried to obtain product U1 with a molecular weight of 364 g / mol. ¹H NMR characterization results: δ 3.5 ppm -CH-NHCO-, δ 1.7-1.8 ppm, -(CH2)2CH-NHCO-, δ 1.3-1.6 ppm, -CH2(CH2)2CH-NHCO-.

[0058] 24 g of ω-cyclopentadecanol (0.1 mol) was added to the reactor, and the mixture was kept under vacuum at 50 °C for 1 h. Then, under a nitrogen atmosphere, 0.011 g (0.1 mmol) of benzyl alcohol, 0.26 g (1 mmol) of tetrabutylammonium hydroxide, and U1 (0.182 g, 0.5 mmol) were added, along with 80 mL of toluene. After thorough mixing, the mixture was repeatedly switched between vacuum and nitrogen atmosphere. The reaction flask was placed in a 35 °C oil bath under a nitrogen atmosphere and reacted for 25 h. Afterward, the reaction flask was opened, and the mixture was diluted with hot toluene, then settled in ethanol. The precipitate was collected and dried to obtain the product. 1H NMR characterization: δ 4.2ppm -COO-CH2-, δ 3.6ppm -CH2-CH2OH, δ 2.3ppm -CH2COO-CH2-, δ 1.55-1.7ppm -COO-CH2-CH2-, and -CH2CH2COOCH2-, δ 1.25-1.4ppm -CH2CH2CH2CH2CH2-.

[0059] Example 2

[0060] Isophorone diamine (3.40 g, 0.02 mol) was dissolved in tetrahydrofuran, and triethylamine (3.96 g, 0.04 mol) was added. The solution was cooled to 0°C, and a cooled solution of m-toluene isocyanate (5.32 g, 0.04 mol) dissolved in 10 mL of tetrahydrofuran was added dropwise. The reaction was maintained at 0°C for 1 h, then the temperature was raised to room temperature, and the reaction was allowed to proceed for 12 h. After the reaction was complete, the mixture was filtered, the precipitate was washed with tetrahydrofuran, and dried to obtain product U2 with a molecular weight of 402 g / mol. 1H NMR characterization results: δ 6.8-7.5 ppm, Ph-, δ 3.5 ppm -CH-NHCO-, δ 3.2CH2NHCO-, δ 2.35 ppm, Ph-CH3, δ 1.7-1.8 ppm, -(CH2)2CH-NHCO-, δ 1.3-1.6 ppm, -CH2(CH2)2CH-NHCO-, δ 1.2CH3-.

[0061] 24 g of ω-cyclopentadecanol (0.1 mol) was added to the reactor, and the mixture was kept under vacuum at 50 °C for 1 h. Then, under a nitrogen atmosphere, 0.022 g (0.2 mmol) of benzyl alcohol, 0.26 g (1 mmol) of tetrabutylammonium hydroxide, and U2 (0.201 g, 0.5 mmol) were added, along with 80 mL of toluene. After thorough mixing, the mixture was repeatedly switched between vacuum and nitrogen atmosphere. The reaction flask was placed in a 35 °C oil bath under a nitrogen atmosphere and reacted for 25 h. Afterward, the reaction flask was opened, and the mixture was diluted with hot toluene, then settled in ethanol. The precipitate was collected and dried to obtain the product. 1H NMR characterization: δ 4.2ppm -COO-CH2-, δ 3.6ppm -CH2-CH2OH, δ 2.3ppm -CH2COO-CH2-, δ 1.55-1.7ppm -COO-CH2-CH2-, and -CH2CH2COOCH2-, δ 1.25-1.4ppm -CH2CH2CH2CH2CH2-.

[0062] Example 3

[0063] 1,4-cyclohexanediamine (4.2 g, 0.02 mol) was dissolved in tetrahydrofuran, and triethylamine (4.1 g, 0.04 mol) was added. The solution was cooled to 0 °C, and a cooled solution of m-toluene isocyanate (5.32 g, 0.04 mol) dissolved in 10 mL of tetrahydrofuran was added dropwise. The reaction was maintained at 0 °C for 1 h, then heated to room temperature and reacted for 12 h. After the reaction was complete, the mixture was filtered, the precipitate was washed with tetrahydrofuran, and dried to obtain product U3 with a molecular weight of 444 g / mol. ¹H NMR characterization results: δ 6.8–7.5 ppm, Ph-, δ 3.5 ppm -CH-NHCO-, δ 2.9–3.3 ppm -CH2-NHCO-, δ 2.35 ppm, Ph-CH3, δ 2.0 ppm -CHCH2-NHCO-, δ 1.3–1.8 ppm, all hydrogen atoms on the six-membered ring, δ 1.2 ppm CH3-.

[0064] 24 g of ω-cyclopentadecanol (0.1 mol) was added to the reactor, and the mixture was kept under vacuum at 50 °C for 1 h. Then, under a nitrogen atmosphere, 0.022 g (0.2 mmol) of benzyl alcohol, 0.26 g (1 mmol) of tetrabutylammonium hydroxide, and 0.222 g (0.5 mmol) of U3 were added, along with 80 mL of toluene. After thorough mixing, the mixture was repeatedly switched between vacuum and nitrogen atmosphere. The reaction flask was placed in a 35 °C oil bath under a nitrogen atmosphere and reacted for 25 h. After the reaction flask was opened, hot toluene was added to dilute the mixture, and the precipitate was settled in ethanol. The precipitate was collected and dried to obtain the product. 1H NMR characterization: δ 4.2ppm -COO-CH2-, δ 3.6ppm -CH2-CH2OH, δ 2.3ppm -CH2COO-CH2-, δ 1.55-1.7ppm -COO-CH2-CH2-, and -CH2CH2COOCH2-, δ 1.25-1.4ppm -CH2CH2CH2CH2CH2-.

[0065] Example 4

[0066] The diurea compound with an alicyclic structure used in this embodiment is the same as that in Example 1, with the following differences:

[0067] 20.4 g of ω-cyclopentadecanol (0.085 mol) and 1.71 g of ε-caprolactone (ε-CL) (0.015 mol) were added to the reactor separately and mixed thoroughly. The mixture was then kept under vacuum at 50 °C for 1 h. Next, under a nitrogen atmosphere, 0.011 g (0.1 mmol) of benzyl alcohol, 0.26 g (1 mmol) of tetrabutylammonium hydroxide, and U1 (0.182 g, 0.5 mmol) were added, along with 80 mL of toluene. After thorough mixing, the mixture was repeatedly switched between vacuum and nitrogen atmosphere. The reaction flask was placed in a 35 °C oil bath under a nitrogen atmosphere and reacted for 25 h. The reaction flask was then opened, and the mixture was diluted with hot toluene, resulting in a precipitate in ethanol. The precipitate was collected and dried to obtain the product. 1H NMR characterization: δ 4.2ppm -COO-CH2-, δ 3.6ppm -CH2-CH2OH, δ 2.3ppm -CH2COO-CH2-, δ 1.55-1.7ppm -COO-CH2-CH2-, and -CH2CH2COOCH2-, δ 1.25-1.4ppm -CH2CH2CH2CH2CH2-.

[0068] Example 5

[0069] The diurea compound with an alicyclic structure used in this embodiment is the same as that in Example 1, with the following differences:

[0070] 12.1 g of ω-cyclopentadecanol (0.05 mol) and 5.7 g of ε-caprolactone (ε-CL) (0.05 mol) were added separately to the reactor and mixed thoroughly. The mixture was then kept under vacuum at 50 °C for 1 h. Next, under a nitrogen atmosphere, 0.011 g (0.1 mmol) of benzyl alcohol, 0.26 g (1 mmol) of tetrabutylammonium hydroxide, and U1 (0.182 g, 0.5 mmol) were added, along with 60 mL of toluene. After thorough mixing, the mixture was repeatedly switched between vacuum and nitrogen atmosphere. The reaction flask was placed in a 35 °C oil bath under a nitrogen atmosphere and reacted for 25 h. The reaction flask was then opened, and the mixture was diluted with hot toluene, resulting in a precipitate in ethanol. The precipitate was collected and dried to obtain the product. 1H NMR characterization: δ 4.2ppm -COO-CH2-, δ 3.6ppm -CH2-CH2OH, δ 2.3ppm -CH2COO-CH2-, δ 1.55-1.7ppm -COO-CH2-CH2-, and -CH2CH2COOCH2-, δ 1.25-1.4ppm -CH2CH2CH2CH2CH2-.

[0071] Example 6

[0072] The diurea compound with an alicyclic structure used in this embodiment is the same as that in Example 1, with the following differences:

[0073] 4.8 g of ω-cyclopentadecanol (0.02 mol) and 9.11 g of ε-caprolactone (ε-CL) (0.08 mol) were added to the reactor separately and mixed thoroughly. The mixture was then kept under vacuum at 50 °C for 1 h. Next, under a nitrogen atmosphere, 0.005 g (0.05 mmol) of benzyl alcohol, 0.26 g (1 mmol) of phenyltrimethylammonium hydroxide, and U1 (0.182 g, 0.5 mmol) were added, along with 50 mL of toluene. After thorough mixing, the mixture was repeatedly switched between vacuum and nitrogen atmosphere. The reaction flask was placed in a 35 °C oil bath under a nitrogen atmosphere and reacted for 25 h. The reaction flask was then opened, and the mixture was diluted with hot toluene, resulting in a precipitate in ethanol. The precipitate was collected and dried to obtain the product. 1H NMR characterization: δ 4.2ppm -COO-CH2-, δ 3.6ppm -CH2-CH2OH, δ 2.3ppm -CH2COO-CH2-, δ 1.55-1.7ppm -COO-CH2-CH2-, and -CH2CH2COOCH2-, δ 1.25-1.4ppm -CH2CH2CH2CH2CH2-.

[0074] Example 7

[0075] The diurea compound with an alicyclic structure used in this embodiment is the same as that in Example 1, with the following differences:

[0076] 19.2 g of ω-cyclopentadecanol (0.08 mol) and 2.88 g of L-lactide (LLA) (0.02 mol) were added to the reactor separately and mixed thoroughly. The mixture was then kept under vacuum at 50 °C for 1 h. Next, under a nitrogen atmosphere, 0.01 g (0.1 mmol) of benzyl alcohol, 0.26 g (1 mmol) of phenyltrimethylammonium hydroxide, and 0.365 g (1 mmol) of U1 were added, along with 70 mL of toluene. After thorough mixing, the mixture was repeatedly switched between vacuum and nitrogen atmosphere. The reaction flask was placed in a 35 °C oil bath under a nitrogen atmosphere and reacted for 25 h. The reaction flask was then opened, and the mixture was diluted with hot toluene, resulting in a precipitate in ethanol. The precipitate was collected and dried to obtain the product. 1H NMR characterization: δ5.1ppm-COO-CH(CH3)-, δ4.2ppm-COO-CH2-, δ3.6ppm-CH2-CH2OH, δ2.3ppm-CH2COO-CH2-, δ1.55-1.7 ppm, -COO-CH2-CH2-, and -CH2CH2COOCH2-, δ1.4-1.5ppm-COO-CH(CH3)-, δ1.25-1.4ppm, -CH2CH2CH2CH2CH2-.

[0077] Example 8

[0078] The diurea compound with an alicyclic structure used in this embodiment is the same as that in Example 2, with the following differences:

[0079] 10.8 g of ω-cyclopentadecanol (0.045 mol) and 7.92 g of L-lactide (LLA) (0.055 mol) were added to the reactor separately and mixed thoroughly. The mixture was then kept under vacuum at 50 °C for 1 h. Next, under a nitrogen atmosphere, 0.01 g (0.1 mmol) of benzyl alcohol, 0.26 g (1 mmol) of phenyltrimethylammonium hydroxide, and 0.402 g (1 mmol) of U2 were added, along with 60 mL of toluene. After thorough mixing, the mixture was repeatedly switched between vacuum and nitrogen atmosphere. The reaction flask was placed in a 35 °C oil bath under a nitrogen atmosphere and reacted for 25 h. The reaction flask was then opened, and the mixture was diluted with hot toluene, resulting in a precipitate in ethanol. The precipitate was collected and dried to obtain the product. 1H NMR characterization: δ5.1ppm-COO-CH(CH3)-, δ4.2ppm-COO-CH2-, δ3.6ppm-CH2-CH2OH, δ2.3ppm-CH2COO-CH2-, δ1.55-1.7 ppm, -COO-CH2-CH2-, and -CH2CH2COOCH2-, δ1.4-1.5ppm-COO-CH(CH3)-, δ1.25-1.4ppm, -CH2CH2CH2CH2CH2-.

[0080] Example 9

[0081] The diurea compound with an alicyclic structure used in this embodiment is the same as that in Example 2, with the following differences:

[0082] 10.8 g of ω-cyclopentadecanol (0.045 mol) was added to the reactor, and the mixture was kept under vacuum at 50 °C for 1 h. Then, under a nitrogen atmosphere, 0.01 g (0.1 mmol) of benzyl alcohol, 0.091 g (1 mmol) of tetramethylammonium hydroxide, and 0.563 g (1.4 mmol) of U2 were added, along with 60 mL of toluene. After thorough mixing, the mixture was repeatedly switched between vacuum and nitrogen atmosphere. The reaction flask was placed in a 25 °C oil bath under a nitrogen atmosphere and reacted for 25 h. After the reaction flask was opened, hot toluene was added to dilute the mixture, and the precipitate was collected in ethanol. The precipitate was dried to obtain the product. 1H NMR characterization: δ 4.2ppm -COO-CH2-, δ 3.6ppm -CH2-CH2OH, δ 2.3ppm -CH2COO-CH2-, δ 1.55-1.7ppm -COO-CH2-CH2-, and -CH2CH2COOCH2-, δ 1.25-1.4ppm -CH2CH2CH2CH2CH2-.

[0083] Comparative Example 1

[0084] 24 g of ω-cyclopentadecanol (0.1 mol) was added to the reactor, and the mixture was kept under vacuum at 50 °C for 1 h. Then, under a nitrogen atmosphere, 0.011 g (0.1 mmol) of benzyl alcohol, 0.26 g (1 mmol) of tetrabutylammonium hydroxide, and 80 mL of toluene were added. After mixing thoroughly, the vacuum and nitrogen atmosphere were switched several times. The reaction flask was placed in a 35 °C oil bath under a nitrogen atmosphere and reacted for 25 h. After that, the reaction flask was opened, and the mixture was diluted with hot toluene and then settled in ethanol. The precipitate was collected and dried to obtain the product.

[0085] Comparative Example 2

[0086] The only difference between this comparative example and Example 1 is that U1 (0.182 g, 0.5 mmol) was replaced with methylene diurea (0.066 g, 0.5 mmol).

[0087] Table 1 Characterization of macrocyclic polyesters and copolyesters

[0088]

[0089] Table 2. Molecular weights of polyesters and copolyesters

[0090] Number average molecular weight weight average molecular weight Molecular weight distribution Macrolides / Other Monomers Example 1 57,000 89,000 1.56 / Example 2 51,000 76,000 1.49 / Example 3 46,000 81,000 1.76 / Example 4 44,000 67,000 1.53 85 / 15 Example 5 43,000 71,000 1.65 58 / 42 Example 6 38,000 57,000 1.50 34 / 66 Example 7 38,000 49,000 1.29 90 / 10 Example 8 31,000 48,000 1.55 61 / 39 Example 9 24,000 41,000 1.71 / Comparative Example 1 3700 6300 1.70 / Comparative Example 2 2000 3900 1.95 /

[0091] As shown in Table 2, in Comparative Example 1, when only an organic base was used as a catalyst, the molecular weight of the resulting polyester was much lower than that of the embodiments in this application. In Comparative Example 2, when other co-catalysts were used, the monomer conversion rate was lower, and the small amount of product obtained was oligomers.

[0092] The various embodiments of the present invention have been described above. These descriptions are exemplary and not exhaustive, nor are they limited to the disclosed embodiments. Many modifications and variations will be apparent to those skilled in the art without departing from the scope and spirit of the described embodiments.

[0093] The endpoints and any values ​​of the ranges disclosed herein are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of the various ranges, the endpoint values ​​of the various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed herein.

Claims

1. A diurea compound having an alicyclic structure, characterized in that, The structural formula of the diurea compound is as follows: In the formula, R is a C6-C18 alicyclic structural unit, and R1 and R2 are each independently selected from at least one of hydrogen atom, C1-C20 alkyl, C3-C20 cycloalkyl, C6-C20 aromatic group, and substituted C6-C20 aromatic group.

2. The diurea compound having an alicyclic structure according to claim 1, wherein, The R is selected from at least one of the structures shown in formula (1) to formula (6); 3. The diurea compound having an alicyclic structure according to claim 1, wherein, R1 and R2 are each independently selected from at least one of hydrogen atom, C10-C20 alkyl, C6-C16 cycloalkyl, C6-C12 phenyl, substituted C6-C12 phenyl, C7-C12 benzyl, and substituted C7-C12 benzyl; the substituted group is selected from at least one of halogen, alkyl, alkoxy, and aryloxy. Preferably, R1 and R2 are each independently selected from at least one of undecyl, dodecyl, tetradecyl, hexadecyl, octadecyl, cyclohexyl, cyclododecyl, adamantyl, phenyl, m-tolyl, p-tolyl, m-chlorophenyl, p-chlorophenyl, 3,4-dichlorophenyl, 3,5-dichlorophenyl, 3-chloro-4-methylphenyl, p-isopropylphenyl, p-bromophenyl, 4-(p-chlorophenoxy)-phenyl, benzyl, 2,4-dimethoxybenzyl, 4-chlorobenzyl, 2-methylbenzyl, 3-methylbenzyl, 2-methoxybenzyl, 4-bromobenzyl, 3,4-dimethoxybenzyl, and 4-isobutoxybenzyl.

4. A method for preparing a diurea compound having an alicyclic structure according to any one of claims 1-3, characterized in that, Includes the following steps: Under the presence of solvent and alkali, a diamine compound with an alicyclic structure is reacted with an isocyanate compound to obtain the diurea compound with an alicyclic structure.

5. The preparation method according to claim 4, wherein, The alicyclic diamine compound is selected from at least one of 4,4'-diaminodicyclohexylmethane, 1,4-cyclohexanediamine, 1,3-cyclohexanediamine, 1,3-cyclohexanedimethylamine, 1,4-cyclohexanedimethylamine, and isophoronediamine.

6. The preparation method according to claim 4, wherein, The isocyanate compound is selected from at least one of phenyl isocyanate, cyclohexane isocyanate, cyclododecane isocyanate, adamantane isocyanate, m-toluene isocyanate, p-toluene isocyanate, m-chlorophenyl isocyanate, p-chlorophenyl isocyanate, undecane isocyanate, dodecane isocyanate, tetradecane isocyanate, hexadecane isocyanate, octadecane isocyanate, 3,4-dichlorophenyl isocyanate, 3,5-dichlorophenyl isocyanate, 3-chloro-4-methylphenyl isocyanate, p-isopropylphenyl isocyanate, p-bromophenyl isocyanate, 4-(p-chlorophenoxy)-phenyl isocyanate, benzyl isocyanate, 2,4-dimethoxybenzyl isocyanate, 4-chloro-benzyl isocyanate, 2-methylbenzyl isocyanate, 3-methylbenzyl isocyanate, 2-methoxybenzyl isocyanate, 4-bromobenzyl isocyanate, 3,4-dimethoxybenzyl isocyanate, and 4-isobutoxybenzyl isocyanate.

7. The preparation method according to claim 4, wherein, The base is selected from at least one of triethylamine, pyridine, and 4-dimethylaminopyridine; the molar ratio of the base to the isocyanate compound is 0.8-2:1, preferably 1-1.5:1; The solvent is selected from at least one of tetrahydrofuran, dichloromethane, chloroform, N,N-dimethylformamide, and ethyl acetate.

8. The preparation method according to claim 4, wherein, The reaction conditions include: a temperature of -10 to 50°C, preferably -5 to 35°C, and a time of 5 to 30 hours, preferably 10 to 20 hours.

9. A catalyst system for the anionic polymerization of macrocyclic lactones, characterized in that, The catalyst system includes a main catalyst and a co-catalyst; Wherein, the main catalyst is an organic base; the co-catalyst is a diurea compound with an alicyclic structure as described in any one of claims 1-3; the molar ratio of the main catalyst to the co-catalyst is 1:1-3, preferably 1:1.3-2.8, and more preferably 1:1.5-2.

6.

10. The catalyst system according to claim 9, wherein, The organic base is a tetra-substituted ammonium hydroxide, preferably selected from at least one of tetramethylammonium hydroxide, tetrabutylammonium hydroxide, and benzyltrimethylammonium hydroxide.

11. A method for anionic polymerization of macrocyclic lactones, characterized in that, Includes the following steps: (1) The polymerization monomer, the initiator and the catalyst system for the anionic polymerization of macrolides as described in claim 9 or 10 are contacted and reacted; the polymerization monomer is a macrolide or a macrolide and other cyclic monomers. (2) The product obtained in step (1) is diluted and dissolved in a good solvent, and then precipitated in a poor solvent to obtain a long-chain aliphatic polyester.

12. The polymerization method according to claim 11, wherein, In step (1), the macrocyclic lactone is selected from at least one of cyclopentadecanolactone, cyclohexadecanolactone, and cyclododecanelactone; The other cyclic monomers are 4-7 membered cyclic monomers, preferably at least one of the following: acetyl lactone, valproic acid lactone, L-lactide, D-lactide, DL-lactide, glycolide, proprolactone, cyclic carbonate, caprolactam, p-oxocyclohexanedione, and morpholinodione. The initiator is a compound having an active hydrogen group, preferably a compound having a hydroxyl and / or an amino group, preferably at least one of benzyl alcohol, 2-phenylethanol, 2,2-diphenylethanol, ethylene glycol, diethylene glycol monomethyl ether, n-propylamine and hexamethylenediamine; preferably, when the polymerizing monomer is a macrolide and other cyclic monomers, the macrolide monomer accounts for 10-90% of the total molar amount of the total polymerizing monomers, preferably 15-85%; The molar ratio of polymeric monomer to organic base is 5-1500:1, preferably 10-1200:1; The molar ratio of polymeric monomer to active hydrogen group is 5-1500:1, preferably 7-1200:

1.

13. The polymerization method according to claim 11, wherein, In step (1), the contact reaction is bulk polymerization or solution polymerization.

14. The polymerization method according to claim 13, wherein, The contact reaction is solution polymerization, and the solvent for solution polymerization is selected from at least one of toluene, xylene, chlorobenzene, dioxane, tetrahydrofuran, dichloromethane, and trichloromethane; Preferably, the concentration of the polymeric monomer is 10wt-90wt%, more preferably 20-70wt%. Preferably, the conditions for the contact reaction include: a polymerization temperature of 20-85℃, more preferably 35-75℃, and a polymerization time of 1-24h, more preferably 1.5-20h.

15. The polymerization method according to claim 11, wherein, In step (2), the good solvent is selected from at least one of toluene, chlorobenzene, xylene, and trichlorobenzene; The undesirable solvent is selected from at least one of petroleum ether, methanol, ethanol, n-hexane, and cyclohexane.

16. The polymerization method according to claim 11, wherein, The long-chain aliphatic polyester has a weight-average molecular weight of 8,000-300,000 and a molecular weight distribution of 1-3.

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