A zinc dicarboxylate catalyst, a preparation method and application thereof

Abstract

The application provides a zinc dicarboxylate catalyst, a preparation method and application thereof, and belongs to the field of catalysts. The preparation method of the zinc dicarboxylate catalyst comprises the following steps: adding a zinc dialkyl solution into a dicarboxylic acid solution, and preparing the zinc dicarboxylate catalyst by a precipitation method under a specific temperature rising procedure. The zinc dicarboxylate is a Zn-R(COO)2 general formula compound, wherein R is a C1-C8 alkyl. Compared with the prior art, the catalyst obtained by the method has the advantages that on the one hand, the purity is more than 99%, and the problem of zinc source residue is avoided; on the other hand, by controlling the temperature change, a catalyst with smaller crystal grain size is prepared. The catalyst prepared by the application has the characteristics of simple preparation method, high catalyst purity, small particle size and excellent catalytic activity, and is especially applied to catalyzing the binary copolymerization reaction of carbon dioxide and an epoxide, and the ternary copolymerization reaction of carbon dioxide, an epoxide and a cyclic anhydride.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of catalyst preparation, and relates to a zinc dicarboxylate catalyst, a preparation method and application thereof. The catalyst prepared by the method is applied to the polymerization processes of carbon dioxide and epoxide, and carbon dioxide, epoxide and cyclic anhydride, and exhibits excellent activity. BACKGROUND

[0002] In the past century, petroleum-based polymers have replaced traditional natural materials and completely changed people's lives because of their low price and strong durability. However, with the large use of these petroleum-based polymers, the emission of carbon dioxide is accelerating, leading to increasingly serious global environmental problems. Therefore, it is becoming a trend to produce polymers with less environmental impact, such as biodegradable plastics. Among them, carbon dioxide-based polycarbonates prepared by using carbon dioxide as a monomer are well known for their biodegradability and various properties, and have attracted widespread attention. Carbon dioxide-based polycarbonates are mainly obtained by ring-opening copolymerization of carbon dioxide and epoxide, and the most economically valuable one is polypropylene carbonate, which is widely used in medical dressings and packaging films due to its excellent biocompatibility and barrier properties. In addition, the introduction of a third monomer, such as cyclic anhydride, in the copolymerization of carbon dioxide and epoxide can better control the biodegradability and improve the deficiencies of carbon dioxide-based polycarbonates in thermal and mechanical properties.

[0003] At present, there are various catalysts applied in the field of carbon dioxide-based polycarbonates, and the zinc dicarboxylate catalyst is recognized as the catalyst that meets the industrialization route, which has high catalytic efficiency, simple preparation, economy, non-toxicity and easy separation from the product. M. Ree et al. (Journal of Polymer Science: Part A: Polymer Chemistry, 1999, 37, 1863) added ground zinc oxide to the toluene solution of glutaric acid and reacted at 55℃ for 4 hours. The catalyst obtained was used for the alternating copolymerization of carbon dioxide and propylene oxide for 40 hours, and the highest activity was 70 g of polypropylene carbonate / g of catalyst (about equivalent to 15.8 g of polypropylene carbonate / g of catalyst / 9 hours). In the post-treatment stage of the catalyst, only acetone was used as a solvent to wash away the unreacted acid source, while the solid zinc source was retained in the catalyst because it was difficult to remove, resulting in a decrease in catalyst purity and inhibition of activity improvement.

[0004] The present application researches and finds that the residue problem of solid zinc source can be solved by changing the zinc source to dialkyl zinc, thereby improving the purity of the catalyst. In addition, by controlling the temperature change, the control of the particle size and crystallinity of the catalyst can be realized, and the zinc glutarate crystal with smaller particle size and moderate crystallinity can be prepared, thereby further improving the activity of the catalyst. SUMMARY

[0005] The present application aims to provide a zinc dicarboxylate catalyst, a preparation method and applications thereof. The catalyst prepared by the method is applied to the polymerization processes of carbon dioxide and epoxide, and carbon dioxide, epoxide and acid anhydride, and exhibits excellent activity.

[0006] The technical scheme of the present application is as follows:

[0007] The zinc dicarboxylate catalyst is mainly composed of Zn-R(COO)2, R is C1-C8 hydrocarbon group, the XRD spectrum of the zinc dicarboxylate catalyst has diffraction peaks at 2θ angles of 12.90±0.5, 22.80±0.4 and 23.10±0.4, the full width at half maximum is higher than 0.4, the crystallinity is 40-70%, and the specific surface area of the zinc dicarboxylate catalyst is 30-100 m 2 / g.

[0008] The preparation method of the zinc dicarboxylate catalyst comprises the following steps: adding a dialkyl zinc solution into a dicarboxylic acid solution, performing a reaction under a specific temperature rising procedure, synthesizing a crude zinc dicarboxylate catalyst by a precipitation method, and finally washing, filtering and drying to obtain the zinc dicarboxylate catalyst, the purity of the zinc dicarboxylate catalyst is ≥99%; the specific temperature rising procedure refers to that the dialkyl zinc solution and the dicarboxylic acid solution are prepared at low temperature, and the initial temperature of the mixture is-5-10℃ after mixing, and the temperature is raised to room temperature at a temperature rising rate of 0.1-1℃ / min.

[0009] Further, the dialkyl zinc is (C x H 2x+1 )2Zn; the good solvent of the reaction system of the dialkyl zinc and the dicarboxylic acid R(COOH)2 is C x H 2x+1 OH, C x H 2x+2 , C x H 2x+1 COC x H 2x+1 , C x H 2x+1 OC x H 2x+1 and C x H 2x Oy One or more of the following, wherein R is a 1-C8 hydrocarbon group, x≥1, y≥1.

[0010] Further, the molar ratio of the dialkylzinc to the dicarboxylic acid is 20:20-22; the mass concentration of the dialkylzinc solution is 10%-20%; and the mass concentration of the dicarboxylic acid solution is 5%-15%.

[0011] Furthermore, the reaction time under a specific heating program is 1 to 12 hours, and mechanical stirring is performed at a speed of 0 to 3000 rpm during the reaction.

[0012] Furthermore, the dicarboxylic acid is one of succinic acid, glutaric acid, adipic acid, pimelic acid, or octanoic acid.

[0013] The zinc dicarboxylic acid catalyst prepared by the above method is used for catalyzing reactions including carbon dioxide and epoxides. The binary copolymerization reaction, and carbon dioxide, epoxides and epoxides The ternary copolymerization reaction, where n is 1, 2 or 3; R1 and R2 are epoxy substituents; and R3 and R4 are acid anhydride substituents.

[0014] Furthermore, R1 and R2 are H, CH2Cl, CH2OBn, methyl, benzene ring, cyclohexene, cyclopentene, naphthalene, or cyclohexyl, and R1 and R2 may be the same or different; R3 and R4 are H, =CH2, benzene ring, cyclohexene, or norbornene ring, and R3 and R4 may be the same or different.

[0015] Further, the epoxide is propylene oxide, ethylene oxide, cyclohexene oxide, epibutylene oxide, epichlorohydrin, phenyl glycidyl ether, allyl glycidyl ether, 2-(ethylene ethoxy)tetrahydro-2H-pyran, tetrahydrofuran, or styrene oxide; the cyclic anhydride is succinic anhydride, phthalic anhydride, cyclopentane-1,2-dicarboxylic anhydride, cyclopropane-1,2-dicarboxylic anhydride, itaconic anhydride, citraconic anhydride, maleic anhydride, or norbornene enediic anhydride.

[0016] Furthermore, the copolymerization reaction temperature is 20–120℃, the pressure is 0.1–10MPa, and the reaction time is 2–100h.

[0017] The beneficial effects of this invention are as follows:

[0018] The catalyst prepared by this invention is simple in method and has high purity. It can be applied to the binary copolymerization reaction of carbon dioxide and epoxide, as well as the ternary copolymerization reaction of carbon dioxide, epoxide and cyclic anhydride, and has the characteristics of high catalytic activity. Attached Figure Description

[0019] Figure 1 WXRD patterns of zinc dicarboxylate prepared for Example 2 and Comparative Examples 1, 2, 4, 5; wherein, ZnGA-10°C is Comparative Example 1, ZnGA-20°C is Comparative Example 2, ZnGA-0.05°C / min is Comparative Example 4, ZnGA-0.20 / min is Example 2, and ZnGA-1.2°C / min is Comparative Example 5.

[0020] Figure 2 Nitrogen adsorption / desorption isotherms of zinc dicarboxylate prepared for Example 2 and Comparative Examples 1, 2, 4, 5; wherein, ZnGA-10°C is Comparative Example 1, ZnGA-20°C is Comparative Example 2, ZnGA-0.05°C / min is Comparative Example 4, ZnGA-0.20 / min is Example 2, and ZnGA-1.2°C / min is Comparative Example 5. DETAILED DESCRIPTION

[0021] The present application will be described in detail below with reference to examples.

[0022] Example 1:

[0023] A solution of 20 mmol of glutaric acid in tetrahydrofuran was prepared to have a mass concentration of about 15%, and then was added to a 100 ml round bottom flask, and the rotation speed was set to 1000 rpm. A solution of 20 mmol of diethyl zinc in n-hexane was slowly added to the flask under a nitrogen atmosphere at -5°C, and then the temperature was increased to room temperature at a rate of 0.1°C / min. The reaction was carried out for 12 hours. After the reaction was completed, unreacted diethyl zinc and dicarboxylic acid were removed by using n-hexane and tetrahydrofuran, respectively, and then the zinc dicarboxylate catalyst was dried. Then, 0.2 g of the catalyst was added to a 100 ml autoclave, and 25 ml of propylene oxide was added to the autoclave. Carbon dioxide was charged into the autoclave, and the autoclave was heated and pressurized to have a pressure of 5 MPa and a temperature of 60°C. The reaction was carried out for 9 hours. After the reaction was completed, the product was discharged from the autoclave, and then was dissolved in dichloromethane. Then, 5% hydrochloric acid was added to the solution to remove the residual catalyst. The solution was washed with water until it became neutral, and then was added to methanol to precipitate the polymer. The polymer was washed to remove impurities such as cyclic carbonate, and then was dried to obtain polypropylene carbonate.

[0024] Example 2:

[0025] Take 20 mmol glutaric acid to configure into a mass concentration of about 15% tetrahydrofuran solution, then add 100 ml round bottom flask, the speed is set to 1000 rpm, slowly add 20 mmol diethyl zinc dissolved in mass concentration of 20% n-hexane solution at 0 ℃ nitrogen environment, after adding, by 0 ℃ to room temperature at the rate of 0.2 ℃ / min, reaction 6 hours. After the reaction, the unreacted diethyl zinc and dicarboxylic acid are removed with n-hexane and tetrahydrofuran respectively, and the zinc dicarboxylate catalyst is obtained after drying. Add 0.2 g of the catalyst in a 100 ml autoclave, then add 25 ml of propylene oxide, fill in carbon dioxide and heat and pressurize, so that the pressure in the autoclave reaches 5 MPa, the temperature in the autoclave is 60 ℃, and the reaction is carried out for 9 hours. After the reaction is completed, the product discharged from the autoclave is dissolved by stirring in dichloromethane, 5% hydrochloric acid is added, the residual catalyst is removed, washed with water to neutral, then methanol is added to make it settle down, and the cyclic carbonate and other impurities in the polymer are washed away, and finally dried to obtain polypropylene carbonate. Figure 1 The XRD spectrum of the zinc dicarboxylate prepared in Example 2 is shown in the accompanying Figure 2 The nitrogen adsorption / desorption isotherm curve of the zinc dicarboxylate prepared in Example 2 is shown in the accompanying

[0026] Example 3:

[0027] Take 20 mmol glutaric acid to configure into a mass concentration of about 15% tetrahydrofuran solution, then add 100 ml round bottom flask, the speed is set to 1000 rpm, slowly add 20 mmol diethyl zinc dissolved in mass concentration of 20% n-hexane solution at 10 ℃ nitrogen environment, after adding, by 10 ℃ to room temperature at the rate of 0.9 ℃ / min, reaction 1 hours. After the reaction, the unreacted diethyl zinc and dicarboxylic acid are removed with n-hexane and tetrahydrofuran respectively, and the zinc dicarboxylate catalyst is obtained after drying. Add 0.2 g of the catalyst in a 100 ml autoclave, then add 25 ml of propylene oxide, fill in carbon dioxide and heat and pressurize, so that the pressure in the autoclave reaches 5 MPa, the temperature in the autoclave is 60 ℃, and the reaction is carried out for 9 hours. After the reaction is completed, the product discharged from the autoclave is dissolved by stirring in dichloromethane, 5% hydrochloric acid is added, the residual catalyst is removed, washed with water to neutral, then methanol is added to make it settle down, and the cyclic carbonate and other impurities in the polymer are washed away, and finally dried to obtain polypropylene carbonate.

[0028] Example 4:

[0029] Take 22 mmol glutaric acid to configure into a mass concentration of about 5% tetrahydrofuran solution, then add 100 ml round bottom flask, the rotation speed is set to 1000 rpm, slowly add the mass concentration of 20% n-hexane solution dissolved with 20 mmol diisopropyl zinc in 5 °C nitrogen environment, after adding, by 5 °C, the temperature rising rate is 0.5 °C / min to room temperature, reaction 4 hours. After the reaction, the unreacted diisopropyl zinc and dicarboxylic acid are removed by n-hexane and tetrahydrofuran respectively, and the zinc dicarboxylate catalyst is obtained after drying. In 100 ml autoclave, add 0.2 g of the catalyst, then add propylene oxide 25 ml, fill in carbon dioxide and heat and pressurize, so that the pressure in the autoclave reaches 5 MPa, the temperature in the autoclave is 60 °C, and the reaction is carried out for 9 hours. After the reaction, the product discharged from the autoclave is added to dichloromethane to stir and dissolve, 5% hydrochloric acid is added, the residual catalyst is removed, washed with water to neutral, then add methanol to make it settle, wash away the impurities such as cyclic carbonate in the polymer, and finally dry to obtain polypropylene carbonate.

[0030] Example 5:

[0031] Take 20 mmol adipic acid to configure into a mass concentration of about 5% tetrahydrofuran solution, then add 100 ml round bottom flask, the rotation speed is set to 1000 rpm, slowly add the mass concentration of 15% n-hexane solution dissolved with 20 mmol diethyl zinc in 0 °C nitrogen environment, after adding, by 0 °C, the temperature rising rate is 0.2 °C / min to room temperature, reaction 6 hours. After the reaction, the unreacted diethyl zinc and dicarboxylic acid are removed by n-hexane and tetrahydrofuran respectively, and the zinc dicarboxylate catalyst is obtained after drying. In 100 ml autoclave, add 0.2 g of the catalyst, then add propylene oxide 25 ml, fill in carbon dioxide and heat and pressurize, so that the pressure in the autoclave reaches 5 MPa, the temperature in the autoclave is 60 °C, and the reaction is carried out for 9 hours. After the reaction, the product discharged from the autoclave is added to dichloromethane to stir and dissolve, 5% hydrochloric acid is added, the residual catalyst is removed, washed with water to neutral, then add methanol to make it settle, wash away the impurities such as cyclic carbonate in the polymer, and finally dry to obtain polypropylene carbonate.

[0032] Example 6:

[0033] Take 20 mmol glutaric acid to configure into a mass concentration of about 5% tetrahydrofuran solution, then add 100 ml round bottom flask, the rotation speed is set to 1000 rpm, slowly add 20 mmol diethyl zinc dissolved in 15% mass concentration n-hexane solution at 0 DEG C nitrogen environment, after adding, by 0 DEG C to room temperature at the rate of 0.2 DEG C / min, reaction 6 hours. After the reaction, respectively with n-hexane and tetrahydrofuran to remove unreacted diethyl zinc and dicarboxylic acid, dry after obtaining dicarboxylic acid zinc catalyst. In 100 ml autoclave, add 0.2 g of the catalyst, then add 25 ml of oxirane, fill in carbon dioxide and heating and pressurization, so that the pressure in the autoclave reaches 1 MPa, the autoclave temperature is 40 DEG C, reaction 9 hours. After the reaction, the product discharged from the autoclave is added to dichloromethane stirring dissolution, and 5% hydrochloric acid is added, the residual catalyst is removed, washed with water to neutral, then add methanol to make it settle, wash the cyclic carbonate and other impurities in the polymer, finally after drying polyethylene carbonate is obtained.

[0034] Example 7:

[0035] Take 20 mmol glutaric acid to configure into a mass concentration of about 5% tetrahydrofuran solution, then add 100 ml round bottom flask, the rotation speed is set to 1000 rpm, slowly add 20 mmol diethyl zinc dissolved in 15% mass concentration n-hexane solution at 0 DEG C nitrogen environment, after adding, by 0 DEG C to room temperature at the rate of 0.2 DEG C / min, reaction 6 hours. After the reaction, respectively with n-hexane and tetrahydrofuran to remove unreacted diethyl zinc and dicarboxylic acid, dry after obtaining dicarboxylic acid zinc catalyst. In 100 ml autoclave, add 0.2 g of the catalyst, then add 25 ml of oxirane, fill in carbon dioxide and heating and pressurization, so that the pressure in the autoclave reaches 1 MPa, the autoclave temperature is 40 DEG C, reaction 9 hours. After the reaction, the product discharged from the autoclave is added to dichloromethane stirring dissolution, and 5% hydrochloric acid is added, the residual catalyst is removed, washed with water to neutral, then add methanol to make it settle, wash the cyclic carbonate and other impurities in the polymer, finally after drying polyethylene carbonate is obtained.

[0036] Example 8:

[0037] A solution of 20 mmol of glutaric acid in tetrahydrofuran having a mass concentration of about 5% was prepared and then added to a 100 ml round bottom flask, the rotation speed was set to 1000 rpm, and a solution of 20 mmol of diethyl zinc in n-hexane having a mass concentration of 15% was slowly added under a nitrogen atmosphere at 5°C, after the addition was completed, the temperature was increased to room temperature at a rate of 0.5°C / min, and the reaction was allowed to proceed for 4 hours. After the reaction was completed, unreacted diethyl zinc and dicarboxylic acid were removed with n-hexane and tetrahydrofuran, respectively, and the zinc dicarboxylate catalyst was obtained after drying. In a 100 ml autoclave, 0.2 g of the catalyst was added, followed by the addition of 20 ml of propylene oxide and 2.8 g of itaconic anhydride, carbon dioxide was charged and the temperature was increased to 70°C under pressure, and the reaction was allowed to proceed for 9 hours. After the reaction was completed, the product discharged from the autoclave was dissolved in dichloromethane with stirring, 5% hydrochloric acid was added, the residual catalyst and anhydride were removed, methanol was then added to cause the polymer to settle, the cyclic carbonate and other impurities in the polymer were washed away, and the terpolymer was obtained after drying.

[0038] Comparative Example 1 (in contrast to Example 2):

[0039] A solution of 20 mmol of glutaric acid in tetrahydrofuran having a mass concentration of about 15% was prepared and then added to a 100 ml round bottom flask, the rotation speed was set to 1000 rpm, and a solution of 20 mmol of diethyl zinc in n-hexane having a mass concentration of 20% was added under a nitrogen atmosphere at -10°C, after the addition was completed, the reaction was allowed to proceed for 6 hours at -10°C. After the reaction was completed, unreacted diethyl zinc and dicarboxylic acid were removed with n-hexane and tetrahydrofuran, respectively, and the zinc dicarboxylate catalyst was obtained after drying. In a 100 ml autoclave, 0.2 g of the catalyst was added, followed by the addition of 25 ml of propylene oxide, carbon dioxide was charged and the temperature was increased to 60°C under pressure, and the reaction was allowed to proceed for 9 hours. After the reaction was completed, the product discharged from the autoclave was dissolved in dichloromethane with stirring, 5% hydrochloric acid was added, the residual catalyst was removed, the product was washed with water until it was neutral, methanol was then added to cause the polymer to settle, the cyclic carbonate and other impurities in the polymer were washed away, and the polypropylene carbonate was obtained after drying. Figure 1 XRD pattern of the zinc dicarboxylate catalyst prepared in Comparative Example 1, Figure 2 Nitrogen adsorption / desorption isotherm of the zinc dicarboxylate catalyst prepared in Comparative Example 1.

[0040] Comparative Example 2 (in contrast to Example 2):

[0041] A solution of 20 mmol of glutaric acid in tetrahydrofuran at a mass concentration of about 15% was prepared and then added to a 100 ml round bottom flask, the rotation speed was set to 1000 rpm, and a solution of 20 mmol of diethyl zinc in n-hexane at a mass concentration of 20% was added at 20°C under a nitrogen atmosphere. After the addition was completed, the reaction was allowed to proceed at 20°C for 6 hours. After the reaction was completed, unreacted diethyl zinc and dicarboxylic acid were removed with n-hexane and tetrahydrofuran, respectively, and the resulting zinc dicarboxylate catalyst was dried. Then, 0.2 g of the catalyst was added to a 100 ml autoclave, 25 ml of propylene oxide was added, carbon dioxide was charged, and heating and pressurization were performed so that the pressure in the autoclave reached 5 MPa and the temperature in the autoclave reached 60°C. The reaction was allowed to proceed for 9 hours. After the reaction was completed, the product discharged from the autoclave was dissolved in dichloromethane with stirring, 5% hydrochloric acid was added to remove the remaining catalyst, and the mixture was washed with water until it became neutral. Then, methanol was added to cause the polymer to settle, and the cyclic carbonate and other impurities in the polymer were washed away. Finally, the resulting polypropylene carbonate was dried. Figure 1 The XRD pattern of the zinc dicarboxylate catalyst prepared in Comparative Example 2 is shown in FIG. 2. Figure 2 The nitrogen adsorption / desorption isotherm of the zinc dicarboxylate catalyst prepared in Comparative Example 2 is shown in FIG. 3.

[0042] Comparative Example 3 (in comparison with Example 2):

[0043] A solution of 20 mmol of glutaric acid in tetrahydrofuran at a mass concentration of about 15% was prepared and then added to a 100 ml round bottom flask, the rotation speed was set to 1000 rpm, and a solution of 20 mmol of diethyl zinc in n-hexane at a mass concentration of 20% was added at 20°C under a nitrogen atmosphere. After the addition was completed, the reaction was allowed to proceed at 20°C for 6 hours. After the reaction was completed, unreacted diethyl zinc and dicarboxylic acid were removed with n-hexane and tetrahydrofuran, respectively, and the resulting zinc dicarboxylate catalyst was dried. Then, 0.2 g of the catalyst was added to a 100 ml autoclave, 25 ml of propylene oxide was added, carbon dioxide was charged, and heating and pressurization were performed so that the pressure in the autoclave reached 5 MPa and the temperature in the autoclave reached 60°C. The reaction was allowed to proceed for 9 hours. After the reaction was completed, the product discharged from the autoclave was dissolved in dichloromethane with stirring, 5% hydrochloric acid was added to remove the remaining catalyst, and the mixture was washed with water until it became neutral. Then, methanol was added to cause the polymer to settle, and the cyclic carbonate and other impurities in the polymer were washed away. Finally, the resulting polypropylene carbonate was dried.

[0044] Comparative Example 4 (in comparison with Example 2):

[0045] A solution of 20 mmol of glutaric acid in tetrahydrofuran at a mass concentration of about 15% was prepared and then added to a 100 ml round bottom flask, the rotation speed was set to 1000 rpm, and a solution of 20 mmol of diethyl zinc in n-hexane at a mass concentration of 20% was added at 0°C under a nitrogen atmosphere, and then the temperature was raised at a rate of 0.05°C / min from 0°C to room temperature. After 6 hours of reaction, unreacted diethyl zinc and dicarboxylic acid were removed with n-hexane and tetrahydrofuran, respectively, and the resulting zinc dicarboxylate catalyst was dried. In a 100 ml autoclave, 0.2 g of the catalyst was added, followed by 25 ml of propylene oxide, and carbon dioxide was charged and heated and pressurized to a pressure of 5 MPa and a temperature of 60°C in the autoclave, and the reaction was carried out for 9 hours. After the reaction was completed, the product discharged from the autoclave was dissolved in dichloromethane with stirring, 5% hydrochloric acid was added to remove the residual catalyst, and then washed with water until neutral, and then methanol was added to precipitate the polymer, and the cyclic carbonate impurities in the polymer were washed away, and finally dried to obtain polypropylene carbonate. Figure 1 XRD spectrum of the zinc dicarboxylate prepared in Comparative Example 4, attached Figure 2 Nitrogen adsorption / desorption isotherm of the zinc dicarboxylate prepared in Comparative Example 4.

[0046] Comparative Example 5 (compared to Example 2):

[0047] A solution of 20 mmol of glutaric acid in tetrahydrofuran at a mass concentration of about 15% was prepared and then added to a 100 ml round bottom flask, the rotation speed was set to 1000 rpm, and a solution of 20 mmol of diethyl zinc in n-hexane at a mass concentration of 20% was added at 0°C under a nitrogen atmosphere, and then the temperature was raised at a rate of 1.2°C / min from 0°C to room temperature. After 6 hours of reaction, unreacted diethyl zinc and dicarboxylic acid were removed with n-hexane and tetrahydrofuran, respectively, and the resulting zinc dicarboxylate catalyst was dried. In a 100 ml autoclave, 0.2 g of the catalyst was added, followed by 25 ml of propylene oxide, and carbon dioxide was charged and heated and pressurized to a pressure of 5 MPa and a temperature of 60°C in the autoclave, and the reaction was carried out for 9 hours. After the reaction was completed, the product discharged from the autoclave was dissolved in dichloromethane with stirring, 5% hydrochloric acid was added to remove the residual catalyst, and then washed with water until neutral, and then methanol was added to precipitate the polymer, and the cyclic carbonate impurities in the polymer were washed away, and finally dried to obtain polypropylene carbonate. Figure 1 XRD spectrum of the zinc dicarboxylate prepared in Comparative Example 5, attached Figure 2 Nitrogen adsorption / desorption isotherm of the zinc dicarboxylate prepared in Comparative Example 5.

[0048] Comparative Example 6 (compared to Example 2):

[0049] Take 20 mmol glutaric acid to configure into a mass concentration of about 15% tetrahydrofuran solution, then add 100 ml round bottom flask, the speed is set to 1000 rpm, under the nitrogen environment at 0 ℃, add 20 mmol zinc acetate dissolved in 20% mass concentration of acetone solution, after adding, by 0 ℃, the temperature rate is 0.2 ℃ / min to room temperature. After 6h reaction, respectively, with acetone and tetrahydrofuran to remove unreacted zinc acetate and dicarboxylic acid, dry to obtain dicarboxylic acid zinc catalyst. In 100 ml autoclave, add 0.2 g of the catalyst, then add propylene oxide 25 ml, fill in carbon dioxide and heating and pressurization, so that the pressure in the kettle reaches 5 MPa, the kettle temperature is 60 ℃, reaction 9 hours. After the reaction, the product discharged from the kettle is added to dichloromethane to stir and dissolve, and 5% hydrochloric acid is added to remove the residual catalyst, washed to neutral with water, then add methanol to make it settle down, wash away the impurities such as cyclic carbonate in the polymer, and finally dry to obtain polypropylene carbonate.

[0050] Comparative example 7 (compared with example 2):

[0051] Take 20 mmol 2,2-dimethyl glutaric acid to configure into a mass concentration of about 15% tetrahydrofuran solution, then add 100 ml round bottom flask, the speed is set to 1000 rpm, under the nitrogen environment at 0 ℃, add 20 mmol diethyl zinc dissolved in 20% mass concentration of n-hexane solution, after adding, by 0 ℃, the temperature rate is 0.2 ℃ / min to room temperature. After 6h reaction, respectively, with n-hexane and tetrahydrofuran to remove unreacted diethyl zinc and dicarboxylic acid, dry to obtain dicarboxylic acid zinc catalyst. In 100 ml autoclave, add 0.2 g of the catalyst, then add propylene oxide 25 ml, fill in carbon dioxide and heating and pressurization, so that the pressure in the kettle reaches 5 MPa, the kettle temperature is 60 ℃, reaction 9 hours. After the reaction, the product discharged from the kettle is added to dichloromethane to stir and dissolve, and 5% hydrochloric acid is added to remove the residual catalyst, washed to neutral with water, then add methanol to make it settle down, wash away the impurities such as cyclic carbonate in the polymer, and finally dry to obtain polypropylene carbonate.

[0052] Comparative example 8:

[0053] Zinc oxide 98 mmol, glutaric acid 100 mmol, toluene 250 ml, added to a 500 ml round bottom flask, reacted for 24 hours under the condition of vigorous stirring at 55°C, after the reaction was finished, washed several times with tetrahydrofuran, dried, and finally obtained the zinc glutarate catalyst. In a 100 ml autoclave, 0.2 g of the catalyst was added, then 25 ml of propylene oxide was added, carbon dioxide was filled and heated and pressurized, so that the pressure in the autoclave reached 5 MPa, the temperature in the autoclave was 60°C, and the reaction was carried out for 9 hours. After the reaction was finished, the product discharged from the autoclave was dissolved by stirring in dichloromethane, 5% hydrochloric acid was added, the residual catalyst was removed, washed with water until neutral, then methanol was added to settle, the cyclic carbonate and other impurities in the polymer were washed away, and finally dried to obtain polypropylene carbonate.

[0054] Comparative Example 9:

[0055] Zinc oxide 98 mmol, glutaric acid 100 mmol, toluene 250 ml, added to a 500 ml round bottom flask, reacted for 24 hours under the condition of vigorous stirring at 55°C, after the reaction was finished, washed several times with tetrahydrofuran, dried, and finally obtained the zinc glutarate catalyst. In a 100 ml autoclave, 0.2 g of the catalyst was added, then 25 ml of propylene oxide was added, carbon dioxide was filled and heated and pressurized, so that the pressure in the autoclave reached 5 MPa, the temperature in the autoclave was 60°C, and the reaction was carried out for 9 hours. After the reaction was finished, the product discharged from the autoclave was dissolved by stirring in dichloromethane, 5% hydrochloric acid was added, the residual catalyst was removed, washed with water until neutral, then methanol was added to settle, the cyclic carbonate and other impurities in the polymer were washed away, and finally dried to obtain polypropylene carbonate.

[0056] Comparative Example 10:

[0057] Zinc oxide 98 mmol, glutaric acid 100 mmol, toluene 250 ml, added to a 500 ml round bottom flask, reacted for 24 hours under the condition of vigorous stirring at 55°C, after the reaction was finished, washed several times with tetrahydrofuran, dried, and finally obtained the zinc glutarate catalyst. In a 100 ml autoclave, 0.2 g of the catalyst was added, then 25 ml of propylene oxide was added, carbon dioxide was filled and heated and pressurized, so that the pressure in the autoclave reached 5 MPa, the temperature in the autoclave was 60°C, and the reaction was carried out for 9 hours. After the reaction was finished, the product discharged from the autoclave was dissolved by stirring in dichloromethane, 5% hydrochloric acid was added, the residual catalyst was removed, washed with water until neutral, then methanol was added to settle, the cyclic carbonate and other impurities in the polymer were washed away, and finally dried to obtain polypropylene carbonate.

[0058] Comparative Example 11:

[0059] Zinc oxide 98 mmol, glutaric acid 100 mmol, toluene 250 ml, added to a 500 ml round bottom flask, reacted for 24 h under vigorous stirring at 55°C, after the reaction was completed, washed several times with tetrahydrofuran, dried, and finally obtained the zinc glutarate catalyst. In a 100 ml autoclave, 0.2 g of the catalyst was added, then added propylene oxide 20 ml and maleic anhydride 2.8 g, respectively, filled with carbon dioxide and heated and pressurized, so that the pressure in the autoclave reached 5 MPa, the temperature in the autoclave was 60°C, and the reaction was carried out for 9 hours. After the reaction was completed, the product discharged from the autoclave was dissolved by stirring in dichloromethane, 5% hydrochloric acid was added, the residual catalyst and anhydride were removed, then methanol was added to settle, the impurities such as cyclic carbonate in the polymer were washed away, and finally dried to obtain the terpolymer.

[0060] Comparative Example 2:

[0061] Zinc oxide 98 mmol, glutaric acid 100 mmol, toluene 250 ml, added to a 500 ml round bottom flask, reacted for 24 h under vigorous stirring at 55°C, after the reaction was completed, washed several times with tetrahydrofuran, dried, and finally obtained the zinc glutarate catalyst. In a 100 ml autoclave, 0.2 g of the catalyst was added, then added propylene oxide 20 ml and maleic anhydride 2.8 g, respectively, filled with carbon dioxide and heated and pressurized, so that the pressure in the autoclave reached 5 MPa, the temperature in the autoclave was 60°C, and the reaction was carried out for 9 hours. After the reaction was completed, the product discharged from the autoclave was dissolved by stirring in dichloromethane, 5% hydrochloric acid was added, the residual catalyst and anhydride were removed, then methanol was added to settle, the impurities such as cyclic carbonate in the polymer were washed away, and finally dried to obtain the terpolymer.

[0062] The catalysts in the above examples were used to catalyze the preparation of binary copolymer and terpolymer, and the polymerization results are shown in Table 1:

[0063] Table 1

[0064]

[0065]

[0066] The WXRD spectrum, nitrogen adsorption / desorption isotherm and purity of the binary zinc carboxylate prepared in Example 2 and Comparative Examples 1, 2, 4 and 5 were analyzed, and the results are shown in Table 2:

[0067] Table 2

[0068]

[0069] From Table 1, in combination with the data of Comparative Examples 8-12 and Examples 1-8, it can be seen that the zinc dicarboxylate catalyst prepared by the present application has much higher activity than the zinc dicarboxylate catalyst prepared by the traditional method in the catalysis of the binary copolymerization of carbon dioxide and epoxide, and the ternary copolymerization of carbon dioxide, epoxide and cyclic anhydride. In comparison with Comparative Examples 1, 2 and 3, too low or too high initial reaction temperature can significantly reduce the activity of the catalyst. In combination with the data of Example 1 and Comparative Examples 4 and 5, too slow or too fast temperature rising rate can also reduce the activity of the catalyst.

[0070] From Table 1, it can be seen that the catalyst of the present application has simple preparation method, high purity and obvious advantages in yield in the catalysis of the binary copolymerization of carbon dioxide and epoxide, and the ternary copolymerization of carbon dioxide, epoxide and cyclic anhydride.

[0071] It should be noted that the description of the embodiments is used to help understand the present application, but does not constitute a limitation on the present application. In addition, the technical features involved in the above-described various embodiments of the present application can be combined with each other as long as there is no conflict. In addition, the above is only some embodiments of the present application, not all embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of protection of the present application.

Claims

1. A zinc dicarboxylate catalyst characterized in that, The zinc dicarboxylate catalyst has Zn-R(COO)2 as main body, R is C1-C8 alkyl, the XRD spectrum of the zinc dicarboxylate catalyst has diffraction peaks at 2θ angles of 12.90±0.5, 22.80±0.4 and 23.10±0.4, the full width at half maximum of all the diffraction peaks is higher than 0.4, the crystallinity is 40-70%, and the specific surface area of the zinc dicarboxylate catalyst is 30-100 m 2 / g.

2. The method of claim 1, wherein the zinc dicarboxylate catalyst is prepared by the steps of: The method comprises the following steps: The zinc dialkyl solution is added into the dicarboxylic acid solution, and the reaction is carried out under a specific temperature rising procedure, and the crude zinc dicarboxylate catalyst is synthesized by a precipitation method, and finally the zinc dicarboxylate catalyst is prepared through washing, filtering and drying, and the purity of the zinc dicarboxylate catalyst is greater than or equal to 99%; the specific temperature rising procedure refers to that the zinc dialkyl solution and the dicarboxylic acid solution are prepared at low temperature, and after mixing, the initial temperature is-5-10 ℃, and the temperature is raised to room temperature at a temperature rising rate of 0.1-1 ℃ / min.

3. The method for preparing a zinc dicarboxylic acid catalyst according to claim 2, characterized in that, dialkylzinc is (C x H 2x+1 )2Zn; a good solvent for the reaction system of dialkylzinc and dicarboxylic acid R(COOH)2 is C x H 2x+1 OH, C x H 2x+2 , C x H 2x+ 1COC x H 2x+1 , C x H 2x+1 OC x H 2x+1 and C x H 2x O y one or more than two kinds of mixture, wherein R is 1~C8 hydrocarbon group, x≥1, y≥1.

4. The method for preparing a zinc dicarboxylic acid catalyst according to claim 2, characterized in that, The molar ratio of the zinc dialkyl to the dicarboxylic acid is 20:20-22; the mass concentration of the zinc dialkyl solution is 10%-20%; and the mass concentration of the dicarboxylic acid solution is 5%-15%.

5. The method for preparing a zinc dicarboxylic acid catalyst according to claim 2, characterized in that, The reaction time is 1-12 h under the specific temperature rising procedure, and mechanical stirring is carried out at a rotating speed of 0-3000 rpm during the reaction.

6. The method for preparing a zinc dicarboxylic acid catalyst according to claim 3, characterized in that, The dicarboxylic acid is one of succinic acid, glutaric acid, adipic acid, pimelic acid or suberic acid.

7. Use of a zinc dicarboxylate catalyst as claimed in claim 1 or a zinc dicarboxylate catalyst prepared by the process as claimed in any one of claims 2 to 6, characterized in that, The zinc dicarboxylate catalyst is applied to catalyze the binary copolymerization reaction including carbon dioxide and epoxide , and the ternary copolymerization reaction of carbon dioxide, epoxide and cyclic anhydride , in which n is 1, 2 or 3; R1, R2 are epoxide substituents; R3, R4 are anhydride substituents.

8. Use of a zinc dicarboxylate catalyst according to claim 7, characterized in that, R1, R2 are H, CH2Cl, CH2OBn, methyl, benzene ring, cyclohexene, cyclopentene, naphthalene or cyclohexyl, and R1 and R2 are the same or different; R3, R4 are H, =CH2, benzene ring, cyclohexene or norbornene ring, and R3 and R4 are the same or different.

9. Use of a zinc dicarboxylate catalyst according to claim 7, characterized in that, The epoxide is propylene oxide, ethylene oxide, cyclohexene oxide, butylene oxide, chloropropylene oxide, phenyl glycidyl ether, allyl glycidyl ether, 2-(oxiranylmethoxy)tetrahydro-2H-pyran, tetrahydrofuran or styrene oxide; and the cyclic anhydride is succinic anhydride, phthalic anhydride, cyclopentane-1,2-dicarboxylic anhydride, cyclopropane-1,2-dicarboxylic anhydride, itaconic anhydride, citraconic anhydride, maleic anhydride or norbornene diacid anhydride.

10. Use of a zinc dicarboxylate catalyst according to claim 7, 8 or 9, characterized in that, The copolymerization temperature is 20-120 ℃, the pressure is 0.1-10 MPa, and the reaction time is 2-100 h.

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