Composite zinc dicarboxylate catalyst and its application in catalytic synthesis of carbon dioxide-based polycarbonate

Abstract

The application discloses a composite zinc dicarboxylate catalyst and application thereof in catalytic synthesis of carbon dioxide-based polycarbonate, and comprises the following components in terms of molar ratio: a) zinc compound: metal hydride compound is 1:0.1-10. The zinc compound is a Zn-R(COO)2 general formula compound, wherein R is a C1-C8 hydrocarbon group; and the metal hydride compound has a general formula of XH Y wherein X is Li, Na, Mg, K, Ca, Be, Sr, Ba, Ra, Fr, Rb or Cs, and Y is 1, 2 or 3. The prepared composite catalyst has the characteristics of simple preparation method, high catalytic activity and low polyether content, and is especially applied to catalytic binary copolymerization of carbon dioxide and epoxide and ternary copolymerization of carbon dioxide, epoxide and cyclic anhydride.

Description

TECHNICAL FIELD

[0001] The present application relates to a preparation method of a composite zinc dicarboxylate catalyst, which is applied to catalyze the binary copolymerization of carbon dioxide and epoxide and the ternary copolymerization of carbon dioxide, epoxide and cyclic anhydride. BACKGROUND

[0002] Carbon dioxide is the main greenhouse gas in the atmosphere. By using the industrial waste carbon dioxide and epoxide or cyclic anhydride as raw materials, carbon dioxide-based polyester plastics can be prepared through copolymerization. This synthesis route not only effectively utilizes industrial waste gas and realizes resource recycling, but also alleviates the white pollution caused by plastics due to the biodegradability of the material. Among them, the most economically valuable is the alternating copolymerization product of carbon dioxide and propylene oxide, polypropylene carbonate, which has excellent biocompatibility and barrier properties and is widely used in packaging materials, films, drug release agents, coatings and polyester polyols. However, due to the chemical inertness of carbon dioxide, the catalytic efficiency of the catalyst is low and the synthesis period is long during the copolymerization process. Therefore, in order to solve these problems, the development of a catalyst system with high catalytic efficiency and simple preparation method has become the focus of the industrialization research of biodegradable carbon dioxide-based polyester plastics. In US Patent US5026676, it was first disclosed that a slightly excessive zinc oxide and dicarboxylic acid were reacted in an aprotic solvent at 55℃ for 40 hours by vigorous stirring, and the catalytic efficiency could reach 22g polypropylene carbonate / g catalyst (about equivalent to 3.3g polypropylene carbonate / g catalyst / 6 hours). The zinc dicarboxylate catalyst prepared by this invention has low manufacturing cost and industrialization potential, but has the problem of low catalytic activity.

[0003] The present application researches and finds that by mixing zinc dicarboxylate catalyst and metal hydride compound at a certain molar ratio and grinding by a ball mill, a composite zinc dicarboxylate catalyst is prepared, which is applied to the field of carbon dioxide-based polycarbonate, not only solves the problem of low catalytic activity, but also has high selectivity and inhibits the generation of polyether. SUMMARY

[0004] The purpose of the present application is to provide a preparation method of a composite zinc dicarboxylate catalyst, which is applied to catalyze the binary copolymerization of carbon dioxide and epoxide and the ternary copolymerization of carbon dioxide, epoxide and cyclic anhydride, and has the characteristics of high catalytic activity and low polyether content.

[0005] The technical scheme of the present application is:

[0006] The application relates to a composite zinc dicarboxylate catalyst, which comprises a main catalyst and a cocatalyst, wherein the main catalyst is a zinc compound with Zn-R(COO)2 as the main body, and the cocatalyst is a metal hydride XH Y , wherein R is a C1-C8 hydrocarbon group, X is Li, Na, Mg, K, Ca, Be, Sr, Ba, Ra, Fr, Rb or Cs, and Y is 1, 2 or 3.

[0007] Further, the molar ratio of the zinc compound to the metal hydride compound is 1:0.1-10.

[0008] Further, the preparation method of the zinc compound is as follows:

[0009] The dicarboxylic acid and the zinc source are mixed in a molar ratio of 100:20-100, and then a proper amount of reaction medium (such as dibutyl ether, toluene, tetrahydrofuran and ethanol) is added, and the mixture is stirred at 0-80℃ for 1-24h. Then, the white powder product is obtained through rotary evaporation, washing, filtration and drying in sequence. The zinc source is one or more of zinc oxide, zinc acetate, zinc nitrate, zinc hydroxide, zinc stearate and dialkyl zinc, and the acid source is dicarboxylic acid R(COOH)2, wherein R is a C1-C8 hydrocarbon group.

[0010] Preferably, the preparation method is as follows: the dialkyl zinc solution is added into the dicarboxylic acid solution, and the reaction is carried out under a specific temperature rising procedure, the crude zinc dicarboxylate catalyst is synthesized through a precipitation method, and finally the zinc dicarboxylate catalyst is obtained through washing, filtration 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 dialkyl zinc 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.

[0011] Further, the dialkyl zinc is (CxH2x +1 )2Zn; the good solvent of the reaction system of the dialkyl zinc and the dicarboxylic acid R(COOH)2 is CxH2x +1 OH, CxH2x +2 , CxH2x +1 COCxH2x +1 , CxH2x +1 OCxH2x +1 and CxH2xOy, wherein R is a C1-C8 hydrocarbon group, x is greater than or equal to 1, and y is greater than or equal to 1; the dicarboxylic acid is one of succinic acid, glutaric acid, adipic acid, pimelic acid or suberic acid.

[0012] Further, the XRD spectrum of the prepared zinc compound 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.

[0013] Further, the molar ratio of the dialkyl zinc to the dicarboxylic acid is 20:20-22, the mass concentration of the dialkyl zinc solution is 10%-20%, the mass concentration of the dicarboxylic acid solution is 5%-15%, and the reaction time is 1-12 h under a specific temperature program, and the mechanical stirring speed is 0-3000 rpm.

[0014] The preparation method of the composite zinc dicarboxylate catalyst comprises the following steps: mixing the zinc compound and the metal hydride according to the molar ratio, and grinding and milling at a high speed for 5-40 hours under an inert atmosphere by using a planetary ball mill at a grinding speed of 100-400 revolutions per minute to obtain the composite catalyst.

[0015] The composite zinc dicarboxylate catalyst is applied to catalyze the binary copolymerization reaction of carbon dioxide and an epoxide , and the ternary copolymerization reaction of carbon dioxide, an epoxide and a cyclic anhydride , wherein n is 1, 2 or 3, R1 and R2 are epoxide substituents, and R3 and R4 are anhydride substituents.

[0016] Further, R1 and R2 are H, CH2Cl, CH2OBn, methyl, a benzene ring, cyclohexene, cyclopentene, naphthalene or cyclohexyl, and R1 and R2 are the same or different; R3 and R4 are H, =CH2, a benzene ring, cyclohexene or norbornene ring, and R3 and R4 are the same or different.

[0017] Further, the epoxide is propylene oxide, ethylene oxide, cyclohexene oxide, butylene oxide, chloropropylene oxide, phenyl glycidyl ether, allyl glycidyl ether, 2-(oxirane ethoxy) tetrahydro-2H-pyran, tetrahydrofuran or oxystyrene; 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.

[0018] Further, the copolymerization reaction temperature is 20-120℃, the pressure is 0.1-10 MPa, and the reaction time is 2-100 h.

[0019] Further, the binary copolymerization reaction of carbon dioxide and epoxide: a proper amount of the complex type zinc carboxylate catalyst is added into an autoclave, then the epoxide is added, carbon dioxide is filled in and heated and pressurized, so that the pressure and temperature in the autoclave reach the set values, and the reaction is carried out. After the reaction is completed, the product discharged from the autoclave is stirred and dissolved in dichloromethane, 5% hydrochloric acid is added to remove the residual catalyst and metal hydride, then water is washed until neutral, methanol is added to make it settle, the impurities such as cyclic carbonate in the polymer are washed away, and finally the ternary copolymer product is obtained after drying. The molar ratio of the zinc compound, the epoxide and the cyclic anhydride is 1:100-600:1-100.

[0020] Further, the ternary copolymerization reaction of carbon dioxide, epoxide and cyclic anhydride: a proper amount of the complex type zinc carboxylate catalyst is added into an autoclave, then the epoxide and the cyclic anhydride are added, carbon dioxide is filled in and heated and pressurized, so that the pressure and temperature in the autoclave reach the set values, and the reaction is carried out. After the reaction is completed, the product discharged from the autoclave is stirred and dissolved in dichloromethane, 5% hydrochloric acid is added to remove the residual catalyst, the anhydride and the metal hydride, then methanol is added to make it settle, the impurities such as cyclic carbonate in the polymer are washed away, and finally the ternary copolymer product is obtained after drying. The molar ratio of the zinc compound, the epoxide and the cyclic anhydride is 1:100-600:1-100.

[0021] The beneficial effects of the present application are:

[0022] The complex type catalyst prepared by the method of the present application has the characteristics of high catalytic activity and low polyether content when applied to the binary copolymerization reaction of carbon dioxide and epoxide, and the ternary copolymerization reaction of carbon dioxide, epoxide and cyclic anhydride. BRIEF DESCRIPTION OF DRAWINGS

[0023] Figure 1 Preparation of polypropylene carbonate for Comparative Example 1 1 H NMR spectrum;

[0024] Figure 2 Preparation of polypropylene carbonate for Example 2 1 H NMR spectrum;

[0025] Figure 3 Preparation of polypropylene carbonate for Example 3 1 H NMR spectrum;

[0026] Figure 4 Yield and columnar analysis of H NMR spectrum of polypropylene carbonate prepared for Comparative Example 1, Example 2 and Example 3 1 H NMR spectrum; DETAILED DESCRIPTION

[0027] The present application will be described in detail below with reference to the examples.

[0028] Example 1:

[0029] Take 22 mmol of pimelic acid to prepare a tetrahydrofuran solution with a mass concentration of about 15%, then add it to a 100 ml round-bottom flask, set the rotation speed to 3000 rpm, and slowly add a 20 mmol diethyl zinc solution dissolved in n-hexane with a mass concentration of 20% under a nitrogen atmosphere at -5°C. After adding, increase the temperature at a rate of 0.1°C / min from -5°C to room temperature, and react for 12 hours. After the reaction is complete, remove the unreacted diethyl zinc and pimelic acid with n-hexane and tetrahydrofuran, respectively, and dry to obtain a zinc pimelate catalyst. Under a nitrogen atmosphere, pre-mix the zinc pimelate with lithium hydride at a molar ratio of 1:0.5, then use a planetary ball mill to grind for 40 h at a rotation speed of 400 rpm to prepare a composite catalyst. Add the corresponding composite catalyst (0.81 mmol of main catalyst) to a 100 ml autoclave, then add propylene oxide (molar ratio of zinc pimelate to propylene oxide 1:442), charge with carbon dioxide and heat and pressurize to make the pressure in the autoclave reach 2 MPa, and the temperature in the autoclave reach 60°C, and react for 6 hours. After the reaction is complete, add the product discharged from the autoclave to dichloromethane to stir and dissolve, add 5% hydrochloric acid to remove residual catalyst and metal hydride, wash with water until neutral, then add methanol to settle, wash out the cyclic carbonate impurities in the polymer, and finally dry to obtain polypropylene carbonate.

[0030] Example 2:

[0031] Take 20 mmol glutaric acid configuration 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 the solution of 20 mmol diethyl zinc in mass concentration of 20% n-hexane 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 glutaric acid, dry after obtaining zinc glutarate catalyst. In the nitrogen atmosphere, glutarate zinc and sodium hydride were premixed according to the molar ratio of 1:1, and then ground by planetary ball mill for 30 h, the rotation speed of the ball mill was 300 r / min, to prepare the composite catalyst. In 100 ml autoclave, the corresponding composite catalyst (main catalyst is 0.92 mmol) was added, then propylene oxide (molar ratio of zinc glutarate to propylene oxide is 1:389) was added, carbon dioxide was filled and heated and pressurized, so that the pressure in the autoclave reached 2 MPa, the temperature in the autoclave was 60 DEG C, and the reaction was carried out for 6 hours. After the reaction, the product discharged from the autoclave was added to dichloromethane and stirred to dissolve, 5% hydrochloric acid was added, the residual catalyst and metal hydride were removed, washed with water until neutral, then methanol was added to make it settle down, the cyclic carbonate impurities in the polymer were washed away, and finally dried to obtain polypropylene carbonate. Figure 2 The polypropylene carbonate prepared in example 2 was 1 H NMR spectrum.

[0032] Example 3:

[0033] Take 20 mmol glutaric acid configuration 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 the solution of 20 mmol diethyl zinc in mass concentration of 20% n-hexane 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 glutaric acid, dry after obtaining zinc glutarate catalyst. In the nitrogen atmosphere, glutarate zinc and sodium hydride were premixed according to the molar ratio of 1:1, and then ground by planetary ball mill for 30 h, the rotation speed of the ball mill was 300 r / min, to prepare the composite catalyst. In 100 ml autoclave, the corresponding composite catalyst (main catalyst is 0.92 mmol) was added, then propylene oxide (molar ratio of zinc glutarate to propylene oxide is 1:389) was added, carbon dioxide was filled and heated and pressurized, so that the pressure in the autoclave reached 2 MPa, the temperature in the autoclave was 60 DEG C, and the reaction was carried out for 6 hours. After the reaction, the product discharged from the autoclave was added to dichloromethane and stirred to dissolve, 5% hydrochloric acid was added, the residual catalyst and metal hydride were removed, washed with water until neutral, then methanol was added to make it settle down, the cyclic carbonate impurities in the polymer were washed away, and finally dried to obtain polypropylene carbonate.Figure 3 The polypropylene carbonate prepared in Example 3 was used as a raw material for the preparation of a polypropylene carbonate resin. 1 H NMR spectrum.

[0034] Example 4:

[0035] Zinc adipate catalyst was prepared by taking 20 mmol of adipic acid to prepare a tetrahydrofuran solution with a mass concentration of about 5%, and then adding it into a 100 ml round-bottom flask, setting the rotation speed to 1000 rpm, slowly adding a 10% n-hexane solution of 20 mmol of diisopropyl zinc dissolved therein under a nitrogen atmosphere at 10°C, and after the addition was completed, increasing the temperature at a rate of 0.9°C / min from 10°C to room temperature, and reacting for 1 hour. After the reaction was completed, unreacted diisopropyl zinc and adipic acid were removed with n-hexane and tetrahydrofuran, respectively, and after drying, zinc adipate catalyst was obtained. After zinc adipate and potassium hydride were premixed in a molar ratio of 1:9 under a nitrogen atmosphere, a planetary ball mill was used for grinding for 5 h at a rotation speed of 100 rpm, and a composite catalyst was prepared. In a 100 ml autoclave, the corresponding composite catalyst (0.86 mmol of main catalyst) was added, followed by the addition of propylene oxide (a molar ratio of zinc adipate to propylene oxide was 1:416), carbon dioxide was filled, and heating and pressurization were performed so that the pressure in the autoclave reached 2 MPa, and the temperature in the autoclave was 60°C, and the reaction was performed for 6 hours. After the reaction was completed, the product discharged from the autoclave was stirred and dissolved in dichloromethane, 5% hydrochloric acid was added, residual catalyst and metal hydride compounds were removed, water was washed until neutral, methanol was then added to cause sedimentation, cyclic carbonate impurities in the polymer were washed away, and finally, after drying, polypropylene carbonate was obtained.

[0036] Example 5:

[0037] Zinc glutarate catalyst was prepared by taking 100 mmol of zinc oxide (99.9%) and 100 mmol of glutaric acid (99.0%), adding 250 ml of toluene into a 500 ml three-necked flask, and reacting for 24 h under the condition of vigorous stirring at 55°C. After the reaction was completed, toluene was removed by rotary evaporation, and acetone was used for washing several times, and finally, after drying, zinc glutarate catalyst was obtained. After zinc glutarate and lithium hydride were premixed in a molar ratio of 1:6 under a nitrogen atmosphere, a planetary ball mill was used for grinding for 30 h at a rotation speed of 300 rpm, and a composite catalyst was prepared. In a 100 ml autoclave, the corresponding composite catalyst (0.92 mmol of main catalyst) was added, followed by the addition of ethylene oxide (a molar ratio of zinc glutarate to ethylene oxide was 1:543), carbon dioxide was filled, and heating and pressurization were performed so that the pressure in the autoclave reached 1 MPa, and the temperature in the autoclave was 40°C, and the reaction was performed for 6 hours. After the reaction was completed, the product discharged from the autoclave was stirred and dissolved in dichloromethane, 5% hydrochloric acid was added, residual catalyst and metal hydride compounds were removed, water was washed until neutral, methanol was then added to cause sedimentation, cyclic carbonate impurities in the polymer were washed away, and finally, after drying, polyethylene carbonate was obtained.

[0038] Example 6:

[0039] 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 20% mass concentration n-hexane solution under 5 ℃ nitrogen environment, after adding, by 5 ℃ to room temperature at the rate of 0.5 ℃ / min, reaction 4 hours. After the reaction, the unreacted diethyl zinc and glutaric acid are removed with n-hexane and tetrahydrofuran respectively, and the zinc glutarate catalyst is obtained after drying. Under the nitrogen atmosphere, the zinc glutarate and sodium hydride are premixed in a molar ratio of 1:3, and then ground by a planetary ball mill for 30 h at a speed of 300 rpm to prepare a composite catalyst. Add the corresponding composite catalyst (the main catalyst is 0.92 mmol) into a 100 ml autoclave, then add propylene oxide and phthalic anhydride (the molar ratio of zinc glutarate, propylene oxide and phthalic anhydride is 1:311:39), fill carbon dioxide and heat and pressurize, so that the pressure in the autoclave reaches 2 MPa, the temperature in the autoclave is 75 ℃, and the reaction is carried out for 6 hours. After the reaction is completed, the product discharged from the autoclave is stirred and dissolved in dichloromethane, 5% hydrochloric acid is added, the residual catalyst, anhydride and metal hydride are removed, then methanol is added to make it settle, the cyclic carbonate impurities in the polymer are washed away, and finally the terpolymer is obtained after drying.

[0040] Example 7:

[0041] Take zinc oxide (99.9%) 100 mmol, adipic acid (99.0%) 100 mmol, toluene 250 ml, add to a 500 ml three-necked flask, react under the condition of 55 ℃ and vigorous stirring for 24 h, after the reaction is completed, remove the toluene by rotary evaporation, wash with acetone several times, and dry to obtain zinc adipate catalyst. Under the nitrogen atmosphere, the zinc adipate and potassium hydride are premixed in a molar ratio of 1:6, and then ground by a planetary ball mill for 30 h at a speed of 300 rpm to prepare a composite catalyst. Add the corresponding composite catalyst (the main catalyst is 0.86 mmol) into a 100 ml autoclave, then add propylene oxide and maleic anhydride (the molar ratio of zinc adipate, propylene oxide and maleic anhydride is 1:333:42), fill carbon dioxide and heat and pressurize, so that the pressure in the autoclave reaches 2 MPa, the temperature in the autoclave is 75 ℃, and the reaction is carried out for 6 hours. After the reaction is completed, the product discharged from the autoclave is stirred and dissolved in dichloromethane, 5% hydrochloric acid is added, the residual catalyst, anhydride and metal hydride are removed, then methanol is added to make it settle, the cyclic carbonate impurities in the polymer are washed away, and finally the terpolymer is obtained after drying.

[0042] Comparative Example 1 (in comparison with Examples 2, 3):

[0043] A 20 mmol of glutaric acid was prepared into a tetrahydrofuran solution with a mass concentration of about 15%, and then added into a 100 ml round bottom flask, the rotation speed was set to 1000 rpm, and a 20 mmol of diethyl zinc dissolved in a n-hexane solution with a mass concentration of 20% was slowly added under a nitrogen atmosphere at 0°C, and after the addition was completed, the temperature was increased to room temperature at a rate of 0.2°C / min, and the reaction was carried out for 6 hours. After the reaction was completed, unreacted diethyl zinc and glutaric acid were removed with n-hexane and tetrahydrofuran respectively, and after drying, a zinc glutarate catalyst was obtained. The zinc glutarate catalyst was ground for 30 h using a planetary ball mill under a nitrogen atmosphere, and the rotation speed of the ball mill was 300 rpm. The ground zinc glutarate catalyst 0.92 mmol was added into a 100 ml autoclave, then propylene oxide (molar ratio of zinc glutarate to propylene oxide 1:389) was added, carbon dioxide was filled, and heating and pressurization were carried out, so that the pressure in the autoclave reached 2 MPa, and the temperature in the autoclave was 60°C, and the reaction was carried out for 6 hours. After the reaction was completed, the product discharged from the autoclave was added into dichloromethane to be stirred and dissolved, 5% hydrochloric acid was added to remove the residual catalyst, washed with water until neutral, then methanol was added to settle, and the cyclic carbonate impurities in the polymer were washed away, and finally dried to obtain polypropylene carbonate. Figure 1 The polypropylene carbonate prepared in Comparative Example 1 was analyzed by 1 HNMR spectrum.

[0044] Comparative Example 2 (in comparison with Examples 2, 3):

[0045] 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 20% mass concentration n-hexane solution at 0 DEG C under nitrogen atmosphere, after adding, by 0 DEG C, the temperature rate is 0.2 DEG C / min to room temperature, reaction 6 hours. After the reaction, the unreacted diethyl zinc and glutaric acid are removed with n-hexane and tetrahydrofuran respectively, and the zinc glutarate catalyst is obtained after drying. Under the nitrogen atmosphere, the zinc glutarate is premixed with sodium hydride at a molar ratio of 1:15, and then ground by a planetary ball mill for 30 h at a speed of 300 rpm to prepare a composite catalyst. In a 100 ml autoclave, the corresponding composite catalyst (0.92 mmol of main catalyst) is added, then propylene oxide (molar ratio of zinc glutarate to propylene oxide 1:389) is added, carbon dioxide is filled and heated and pressurized, so that the pressure in the autoclave reaches 2 MPa, and the temperature in the autoclave is 60 DEG C, and the reaction is carried out for 6 hours. After the reaction, the product discharged from the autoclave is stirred and dissolved in dichloromethane, 5% hydrochloric acid is added, the residual catalyst and metal hydride are removed, washed with water to neutral, then methanol is added to make it settle, and the cyclic carbonate impurities in the polymer are washed away, and finally dried to obtain polypropylene carbonate.

[0046] Comparative Example 3 (compared with Example 5):

[0047] Take zinc oxide (99.9%) 100 mmol, glutaric acid (99.0%) 100 mmol, toluene 250 ml, add to a 500 ml three-necked flask, and react at 55 DEG C under intensive stirring for 24 h. After the reaction, toluene is removed by rotary evaporation, and acetone is washed several times, and finally the zinc glutarate catalyst is obtained after drying. Under the nitrogen atmosphere, the zinc glutarate catalyst is ground by a planetary ball mill for 30 h at a speed of 300 rpm. In a 100 ml autoclave, the ground zinc glutarate catalyst 0.92 mmol is added, then ethylene oxide (molar ratio of zinc glutarate to ethylene oxide 1:543) is added, carbon dioxide is filled and heated and pressurized, so that the pressure in the autoclave reaches 1 MPa, and the temperature in the autoclave is 40 DEG C, and the reaction is carried out for 6 hours. After the reaction, the product discharged from the autoclave is stirred and dissolved 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, and the cyclic carbonate impurities in the polymer are washed away, and finally dried to obtain polyethylene carbonate.

[0048] Comparative Example 4 (compared with Example 6):

[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, slowly add the mass concentration of 20% n-hexane solution dissolved with 20 mmol diethyl zinc in 5 ℃ nitrogen environment, after adding, by 5 ℃, the temperature rising rate is 0.5 ℃ / min to room temperature, reaction 4 hours. After the reaction is completed, the unreacted diethyl zinc and glutaric acid are removed with n-hexane and tetrahydrofuran respectively, and the zinc glutarate catalyst is obtained after drying. The zinc glutarate catalyst is ground by a planetary ball mill under a nitrogen atmosphere for 30 h, and the rotation speed of the ball mill is 300 r / min. Add 0.92 mmol of ground zinc glutarate catalyst in a 100 ml autoclave, then add propylene oxide and phthalic anhydride respectively (the molar ratio of zinc glutarate, propylene oxide and phthalic anhydride is 1:311:39), fill carbon dioxide and heat and pressurize, so that the pressure in the autoclave reaches 2 MPa, and the temperature in the autoclave is 75 ℃, and the reaction is carried out for 6 hours. After the reaction is completed, the product discharged from the autoclave is stirred and dissolved in dichloromethane, 5% hydrochloric acid is added, the residual catalyst and anhydride are removed, then methanol is added to make it settle, the cyclic carbonate impurities in the polymer are washed away, and finally the ternary copolymer is obtained after drying.

[0050] Comparative example 5 (compared with example 7):

[0051] Take zinc oxide (99.9%) 100 mmol, adipic acid (99.0%) 100 mmol, toluene 250 ml, add to a 500 ml three-necked flask, and react under the condition of 55 ℃ and vigorous stirring for 24 h. After the reaction is completed, the toluene is removed by rotary evaporation, and the zinc adipate catalyst is obtained after washing with acetone several times and drying. The zinc adipate catalyst is ground by a planetary ball mill under a nitrogen atmosphere for 30 h, and the rotation speed of the ball mill is 300 r / min. Add 0.86 mmol of ground zinc adipate catalyst in a 100 ml autoclave, then add propylene oxide and maleic anhydride respectively (the molar ratio of zinc adipate, propylene oxide and maleic anhydride is 1:333:42), fill carbon dioxide and heat and pressurize, so that the pressure in the autoclave reaches 2 MPa, and the temperature in the autoclave is 75 ℃, and the reaction is carried out for 6 hours. After the reaction is completed, the product discharged from the autoclave is stirred and dissolved in dichloromethane, 5% hydrochloric acid is added, the residual catalyst and anhydride are removed, then methanol is added to make it settle, the cyclic carbonate impurities in the polymer are washed away, and finally the ternary copolymer is obtained after drying. The catalyst in each of the above examples and comparative examples is used to catalyze the preparation of binary copolymer and ternary copolymer, and the polymerization results are shown in Table 1:

[0052] Table 1

[0053]

[0054]

[0055] Examples 1-5 and Comparative Examples 1-3 are the results of the application of the composite zinc dicarboxylate catalyst to the binary copolymerization of carbon dioxide and propylene oxide or ethylene oxide, and Examples 6-7 and Comparative Examples 4-5 are the results of the application of the composite zinc dicarboxylate catalyst to the ternary copolymerization of carbon dioxide, propylene oxide and phthalic anhydride or maleic anhydride.

[0056] As can be seen from Table 1, the zinc compound catalysts of Examples 1, 2, 3, 4, 6 and Comparative Examples 1, 2, 4 are derived from the preferred preparation method, and the zinc compound catalysts of Examples 5, 7 and Comparative Examples 3, 5 are derived from the general preparation method. The composite catalysts obtained by compounding the zinc compound catalysts prepared by the two methods with metal hydride compounds are applied to the binary copolymerization of carbon dioxide and epoxide, and the ternary copolymerization of carbon dioxide, epoxide and cyclic acid anhydride, and the activity and selectivity of the composite catalysts are higher than those of the single catalysts prepared by the respective methods. As compared with Comparative Examples 1, 2 and Examples 2, 3, compounding the same zinc compound catalyst with metal hydride compounds at different molar ratios has a great influence on the activity and selectivity. When an appropriate amount of metal hydride compound is compounded with the zinc compound catalyst, the activity and selectivity of the composite catalyst are obviously improved. As compared with Comparative Example 1, the activity of Examples 2, 3 is increased by 39.6% and 63.5%, respectively, and the polycarbonate content is increased by 2.4% and 4.9%, respectively. However, when an excess amount of metal hydride compound is compounded, the activity and selectivity of the composite catalyst are obviously decreased. Therefore, the appropriate molar ratio is particularly important for the activity and selectivity. As can be seen from Table 1, the composite zinc dicarboxylate catalyst prepared by the present application is applied to the binary copolymerization of carbon dioxide and epoxide, and the ternary copolymerization of carbon dioxide, epoxide and cyclic acid anhydride, and the preparation method is simple, the zinc compound catalyst of general formula Zn-R(COO)2(R is C1-C8 hydrocarbon group) and the metal hydride compound of general formula XH Y (X is Li, Na, Mg, K, Ca, Be, Sr, Ba, Ra, Fr, Rb or Cs, and Y is 1, 2 or 3) are used together as catalysts, and the yield and polycarbonate content are obviously improved.

[0057] It should be noted that the above description of the embodiments is intended to help understand the present application, but does not constitute a limitation on the present application. Furthermore, the technical features involved in each of the above-described embodiments of the present application can be combined with each other as long as there is no conflict. In addition, the above only describes some embodiments of the present application, but not all embodiments. Based on the embodiments of the present application, all other embodiments obtained by a person of ordinary skill in the art without creative labor fall within the scope of protection of the present application.

Claims

1. A composite zinc dicarboxylate catalyst characterized in that, The composite type zinc dicarboxylate catalyst comprises a main catalyst and a cocatalyst, the main catalyst is a zinc compound with Zn-R(COO)2 as the main body, and the cocatalyst is a metal hydride XH Y , wherein R is a C1-C8 hydrocarbon group, X is Li, Na, Mg, K, Ca, Be, Sr, Ba, Ra, Fr, Rb or Cs, and Y is 1, 2 or 3.

2. The complex type zinc bicine catalyst according to claim 1, characterized by, The molar ratio of the zinc compound to the metal hydride compound is 1:0.1-10.

3. The complexed zinc dicarboxylate catalyst of claim 1, wherein, The preparation method of the zinc compound is as follows: a dialkyl zinc solution is added into a dicarboxylic acid solution, and a crude zinc dicarboxylate catalyst is synthesized by precipitation under a specific temperature rising procedure, and finally the zinc dicarboxylate catalyst is prepared by washing, filtering and drying, and the purity of the zinc dicarboxylate catalyst is greater than or equal to 99%; the specific temperature rising procedure is that the dialkyl zinc 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.

4. The complexed zinc bicine catalyst of claim 3, wherein, dialkylzinc is (C x H 2x+1 )2Zn; the 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 , or a mixture of two or more of them, wherein R is C1-C8 hydrocarbon group, x≥1, y≥1; the dicarboxylic acid is one of succinic acid, glutaric acid, adipic acid, pimelic acid or suberic acid; the XRD spectrum of the prepared zinc compound 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 peaks is higher than 0.4 and the crystallinity is 40-70%, the specific surface area of the zinc dicarboxylate catalyst is 30-100 m 2 / g.

5. The complexed zinc bicine catalyst of claim 3, wherein, The molar ratio of the dialkyl zinc to the dicarboxylic acid is 20:20-22; the mass concentration of the dialkyl zinc solution is 10%-20%; the mass concentration of the dicarboxylic acid solution is 5%-15%; and 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. A method for producing the complex type zinc biscalboxylate catalyst as claimed in any one of claims 1 to 5, characterized by, The zinc compound and the metal hydride compound are mixed according to the molar ratio, and are ground by a planetary ball mill at high speed for 5-40 hours in an inert atmosphere, and the grinding rotating speed is 100-400 revolutions per minute, so as to prepare the composite catalyst.

7. The use of the composite zinc carboxylate catalyst according to any one of claims 1 to 5 or the composite zinc carboxylate catalyst prepared by the method according to claim 6, characterized in that, The complex zinc dicarboxylate catalyst is used to catalyze the copolymerization of carbon dioxide and an epoxide and the terpolymerization of carbon dioxide, an epoxide and a cyclic anhydride wherein n is 1, 2 or 3; R1, R2 are epoxide substituents; R3, R4 are anhydride substituents.

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

9. The use of the composite zinc bicine 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 oxystyrene; 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. The use of the composite zinc bicine catalyst according to claim 7, 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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