An acid-modified zinc carboxylate catalyst, its preparation method and application

Abstract

The present invention provides an acid-modified zinc carboxylate catalyst, a preparation method thereof and an application thereof, belonging to the technical field of catalysts. The preparation method provided by the present invention comprises the following steps: mixing zinc oxide, a dicarboxylic acid and a solvent, and carrying out a metathesis reaction to obtain a mixed solution containing zinc carboxylate; mixing the mixed solution containing zinc carboxylate with an acidic modifier, and carrying out a modification reaction to obtain an acid-modified zinc carboxylate catalyst. By using an acidic modifier to modify zinc carboxylate, the present invention can reduce the particle size of zinc carboxylate and expose the active sites on the surface of zinc carboxylate; the acidic modifier can also corrode the surface of zinc carboxylate to expose more active sites and improve the catalytic activity; the acidic modifier can also change the structure of zinc carboxylate to reduce the binding force between hydroxyl groups and zinc carboxylate, so that when the acid-modified zinc carboxylate catalyst is used as a catalyst for preparing poly(propylene carbonate) and poly(cyclohexylene carbonate), it is more likely to participate in the reaction of epoxy and significantly reduce the catalytic reaction time.

Description

Technical Field

[0001] The invention relates to the technical field of catalysts, and in particular to an acid-modified zinc carboxylate catalyst and a preparation method and application thereof. Background Art

[0002] The carbonate structure in polypropylene carbonate (PPC) and polycyclohexylene carbonate (PCHC) is biodegradable, making PPC and PCHC a degradable material that can be used to replace many non-degradable products used in medicine, food, agriculture and other fields. PPC is obtained by copolymerization of carbon dioxide and propylene oxide under the action of a catalyst, and PCHC is produced by copolymerization of carbon dioxide and cyclohexene oxide. It uses greenhouse gas carbon dioxide as a raw material, which can simultaneously reduce white pollution and environmental pollution caused by the greenhouse effect, and has broad application prospects.

[0003] At present, the types of catalysts for preparing PPC include: zinc-cobalt bimetallic catalytic system, Schiff base metal complex system, porphyrin catalysts, rare earth coordination catalysts, etc. The types of catalysts for preparing PCHC include Salen metal complexes (Schiff base metal complexes), rare earth complexes, metal-free catalysts and bimetallic catalysts. However, the cost of zinc-cobalt bimetallic catalytic system is high, the preparation method is complicated, and the activity and stability are relatively poor; the preparation of Schiff base metal complex system catalysts requires precise control of the structure of the ligand and the type and proportion of metal ions, and also needs to consider factors such as the coordination mode and stability between the ligand and the metal ion, all of which increase the complexity and difficulty of catalyst preparation; porphyrin catalysts are easy to deactivate and have poor stability, and the preparation of porphyrin catalysts involves a variety of organic reagents and metal salts, and the prices of these raw materials are relatively high; the preparation process of rare earth coordination catalysts is complicated and the cost is high. It can be seen that although these traditional catalysts have good activity, they have problems such as complex synthesis steps, air sensitivity, and difficulty in preservation, which to a certain extent limit the large-scale production of PPC and PCHC and their promotion in high-quality application scenarios.

[0004] Zinc dicarboxylate catalysts have simple synthesis steps, epoxide and CO 2 With advantages such as high degree of alternation, stability and easy storage, it has good application prospects as a catalyst for the preparation of PPC and PCHC and is the most promising type of catalyst for industrialization. However, the activity of zinc dicarboxylate catalysts is relatively low. When used as catalysts for the preparation of PPC and PCHC, they have problems such as large feed volume and long reaction time, which seriously limits the industrial application of zinc dicarboxylate catalysts.

[0005] Therefore, there is an urgent need to provide a method for preparing an acid-modified zinc carboxylate catalyst that is efficient and suitable for industrial application. Summary of the invention

[0006] The object of the present invention is to provide an acid-modified zinc carboxylate catalyst which is highly efficient and suitable for industrial application, and a preparation method and application thereof.

[0007] In order to achieve the above-mentioned object of the invention, the present invention provides the following technical solutions:

[0008] The present invention provides a method for preparing an acid-modified zinc carboxylate catalyst, comprising the following steps:

[0009] (1) mixing zinc oxide, a dicarboxylic acid and a solvent, and performing a double decomposition reaction to obtain a mixed solution containing zinc carboxylate;

[0010] (2) The mixed solution containing zinc carboxylate obtained in step (1) is mixed with an acidic modifier to carry out a modification reaction to obtain an acid-modified zinc carboxylate catalyst.

[0011] Preferably, the dicarboxylic acid in step (1) comprises one or more of C4-C7 fatty dicarboxylic acids.

[0012] Preferably, in step (1), the molar ratio of zinc oxide to dicarboxylic acid is 1:(0.9-0.98).

[0013] Preferably, the temperature of the metathesis reaction in step (1) is 20-45° C., and the time of the metathesis reaction is 7-8 h.

[0014] Preferably, the acidic modifier in step (2) comprises C4-C14 fatty acid and / or inorganic acid.

[0015] Preferably, the C4-C14 fatty acid is one or more of butyric acid, caproic acid, caprylic acid, capric acid, undecanoic acid, lauric acid, tridecanoic acid and myristic acid.

[0016] Preferably, the molar ratio of the zinc oxide in step (1) to the acidic modifier in step (2) is 12:(0.2-2).

[0017] Preferably, the temperature of the modification reaction in step (2) is 70-80° C., and the modification reaction time is 2-3 h.

[0018] The present invention also provides an acid-modified zinc carboxylate catalyst prepared by the preparation method described in the above technical scheme.

[0019] The present invention also provides the use of the acid-modified zinc carboxylate catalyst described in the above technical solution as a catalyst for preparing polypropylene carbonate or polycyclohexylene carbonate.

[0020] The present invention provides a method for preparing an acid-modified zinc carboxylate catalyst, comprising the following steps: mixing zinc oxide, a dicarboxylic acid and a solvent, performing a double decomposition reaction, and obtaining a mixed solution containing zinc carboxylate; mixing the mixed solution containing zinc carboxylate with an acidic modifier, performing a modification reaction, and obtaining an acid-modified zinc carboxylate catalyst. The present invention modifies zinc carboxylate by using an acidic modifier, and the acidic modifier can reduce the particle size of zinc carboxylate, expose the active sites on the surface of zinc carboxylate, and improve the catalytic activity; on the other hand, the acidic modifier can corrode the surface of zinc carboxylate, expose more active sites, and improve its catalytic activity; in addition, the zinc carboxylate activity is low, and the acidic modifier can change the structure of zinc carboxylate, so that the binding force between hydroxyl and zinc carboxylate is reduced, so that the acid-modified zinc carboxylate catalyst is more likely to participate in the epoxy reaction when used as a catalyst for preparing polypropylene carbonate, and the catalytic reaction time is significantly reduced. The results of the examples show that when the acid-modified zinc carboxylate catalyst prepared by the present invention is used as a catalyst for preparing polypropylene carbonate or polycyclohexylene carbonate, the catalytic reaction time is shortened from 30 h to 15 h, and the catalyst has excellent catalytic activity and is suitable for industrial application. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 XRD patterns of the acid-modified zinc carboxylate catalysts prepared in Example 1 and Comparative Example 1 of the present invention;

[0022] Figure 2 IR graphs of the acid-modified zinc carboxylate catalysts prepared in Example 1 of the present invention and Comparative Example 1. DETAILED DESCRIPTION

[0023] The present invention provides a method for preparing an acid-modified zinc carboxylate catalyst, comprising the following steps:

[0024] (1) mixing zinc oxide, a dicarboxylic acid and a solvent, and performing a double decomposition reaction to obtain a mixed solution containing zinc carboxylate;

[0025] (2) The mixed solution containing zinc carboxylate obtained in step (1) is mixed with an acidic modifier to carry out a modification reaction to obtain an acid-modified zinc carboxylate catalyst.

[0026] The invention mixes zinc oxide, dicarboxylic acid and solvent, and performs double decomposition reaction to obtain a mixed solution containing zinc carboxylate.

[0027] The present invention has no particular limitation on the particle size of the zinc oxide, and conventional commercially available zinc oxide powder may be used. In an embodiment of the present invention, the zinc oxide may be sourced from Shanghai MacLean Biochemical Technology Co., Ltd., and the purity of the zinc oxide is 99-99.5%.

[0028] In the present invention, the dicarboxylic acid preferably includes one or more of C4-C7 aliphatic dicarboxylic acids, more preferably one or more of C5-C6 aliphatic dicarboxylic acids, and further preferably glutaric acid. The present invention uses dicarboxylic acids and zinc oxide to undergo a double decomposition reaction to form zinc carboxylate, which contains hydroxyl groups on its surface and can react with epoxy to initiate the formation of polypropylene carbonate, thereby playing the role of a catalyst.

[0029] In the present invention, the molar ratio of zinc oxide to dicarboxylic acid is preferably 1:(0.9-0.98), more preferably 1:(0.95-0.98). The present invention controls the molar ratio of zinc oxide to dicarboxylic acid within the above range, so that the raw materials can fully react to form zinc carboxylate.

[0030] In the present invention, the solvent preferably includes toluene or xylene, more preferably toluene. The present invention uses the above solvent as the reaction medium.

[0031] The present invention has no particular limitation on the amount of the solvent, as long as it can immerse the zinc oxide. In an embodiment of the present invention, the ratio of the mass of the zinc oxide to the volume of the solvent can be (8-41) g: (200-500) mL.

[0032] The present invention has no special limitation on the method of mixing the zinc oxide, the dicarboxylic acid and the solvent, and a conventional mixing method can be used to uniformly mix the three. In an embodiment of the present invention, the method of mixing the zinc oxide, the dicarboxylic acid and the solvent can be: mixing the zinc oxide and the solvent under stirring to obtain a zinc oxide dispersion, and stirring and mixing the dicarboxylic acid and the zinc oxide dispersion. The present invention uniformly mixes the three under stirring.

[0033] In the present invention, the temperature of the metathesis reaction is preferably 20-45°C, more preferably 30-40°C; the time of the metathesis reaction is preferably 7-8h, more preferably 7.5-8h. The present invention controls the temperature and time of the metathesis reaction within the above ranges, so that zinc oxide and dicarboxylic acid can fully react to obtain zinc carboxylate.

[0034] In the present invention, the double decomposition reaction is preferably carried out under stirring. The present invention can promote the full contact between zinc oxide and dicarboxylic acid by stirring, and promote the double decomposition reaction more fully. In the present invention, the rotation speed of the stirring is preferably 1000~2300r / min, and more preferably 1400~2000r / min. The present invention performs vigorous stirring at the above rotation speed, which can improve the reaction efficiency of zinc oxide and dicarboxylic acid.

[0035] After obtaining the mixed solution containing zinc carboxylate, the present invention mixes the mixed solution containing zinc carboxylate with an acidic modifier to carry out a modification reaction to obtain an acid-modified zinc carboxylate catalyst.

[0036] In the present invention, the acidic modifier preferably includes C4~C14 fatty acids and / or inorganic acids, and more preferably a mixed modifier composed of C4~C14 fatty acids and inorganic acids or C4~C14 fatty acids. In the present invention, the C4~C14 fatty acids preferably include C6~C12 fatty acids, and more preferably one or more of butyric acid, caproic acid, capric acid, undecanoic acid, lauric acid, tridecanoic acid and myristic acid, and more preferably one or more of lauric acid, tridecanoic acid and myristic acid. In the present invention, the inorganic acid is preferably dilute hydrochloric acid or dilute phosphoric acid, and the concentration of the dilute hydrochloric acid or dilute phosphoric acid is preferably 5~6 mol / L. In the present invention, when the acidic modifier is a mixed modifier composed of C4~C14 fatty acids and inorganic acids, the molar ratio of the C4~C14 fatty acids and inorganic acids is preferably (1~4): (0.1~1), and more preferably (1~3): (0.5~0.8). The acidic modifier used in the present invention can reduce the particle size of zinc carboxylate and corrode the surface of zinc carboxylate to expose more active sites and improve catalytic activity; and the acidic modifier can change the structure of zinc carboxylate to reduce the binding force between hydroxyl group and zinc carboxylate.

[0037] In the present invention, the molar ratio of zinc oxide to the acidic modifier is preferably 12: (0.2-2), more preferably 12: 1. The present invention controls the molar ratio of zinc oxide to the acidic modifier within the above range, which is more conducive to further improving the activity of the zinc carboxylate catalyst.

[0038] The present invention has no particular limitation on the method for mixing the zinc carboxylate-containing mixed solution with the acidic modifier, and any conventional mixing method can be used to uniformly mix the two. In the present invention, the mixing method is preferably stirring.

[0039] In the present invention, the temperature of the modification reaction is preferably 70-80°C, more preferably 75-80°C; the time of the modification reaction is preferably 2-3h, more preferably 2.5-3h. The present invention is more conducive to promoting the full modification of the zinc carboxylate by the acidic modifier at the above temperature and time.

[0040] In the present invention, the modification reaction is preferably carried out under stirring. The present invention promotes sufficient contact between the acidic modifier and the zinc carboxylate by stirring. In the present invention, the stirring speed is preferably 1000-2300 r / min, more preferably 1400-2000 r / min. The present invention performs vigorous stirring at the above speed, which can improve the reaction efficiency of the acidic modifier and the zinc carboxylate.

[0041] In the present invention, after the modification reaction, the system after the modification reaction is preferably filtered, washed and dried in sequence to obtain an acid-modified zinc carboxylate catalyst. The present invention has no particular limitation on the operation methods of the filtering, washing and drying, and conventional filtering, washing and drying methods can be used. In an embodiment of the present invention, the washing reagent can be acetone.

[0042] The present invention also provides an acid-modified zinc carboxylate catalyst prepared by the preparation method described in the above technical scheme.

[0043] The present invention can reduce the particle size of the zinc carboxylate catalyst through acid modification, increase the specific surface area of ​​the acid-modified zinc carboxylate catalyst, expose more active sites of the acid-modified zinc carboxylate catalyst, and thus improve its catalytic activity.

[0044] The present invention also provides the use of the acid-modified zinc carboxylate catalyst described in the above technical solution in the preparation of polypropylene carbonate and polycyclohexylene carbonate catalyst.

[0045] The present invention does not particularly limit the method for using the acid-modified zinc carboxylate catalyst as a catalyst for preparing polypropylene carbonate and polycyclohexylene carbonate. The conventional method for using the acid-modified zinc carboxylate catalyst as a catalyst for preparing polypropylene carbonate and polycyclohexylene carbonate can be used.

[0046] In the embodiment of the present invention, the reaction principle for preparing polypropylene carbonate is preferably as shown in formula (1), and the reaction principle for preparing polycyclohexylene carbonate is preferably as shown in formula (2):

[0047] Formula (1);

[0048] Formula (2).

[0049] The acid-modified zinc carboxylate catalyst provided by the present invention has excellent stability and fully exposed active sites, so that it has excellent catalytic activity; in addition, the acidic modifier can change the structure of the zinc carboxylate, so that the binding force between the hydroxyl group and the zinc carboxylate is reduced, so that when the acid-modified zinc carboxylate catalyst is used as a catalyst for preparing polypropylene carbonate, it is easier to participate in the epoxy reaction, significantly reducing the catalytic reaction time, thereby improving the catalytic efficiency of preparing polypropylene carbonate.

[0050] The technical solutions in the present invention will be described clearly and completely below in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0051] Example 1

[0052] A method for preparing an acid-modified zinc carboxylate catalyst comprises the following steps:

[0053] (1) 8.139 g of zinc oxide and 200 mL of toluene were stirred to obtain a zinc oxide dispersion, 12.936 g of glutaric acid was stirred to mix with the zinc oxide dispersion, and the mixture was heated to reflux at 45° C. with vigorous stirring (2000 r / min) for 3 h to perform a double decomposition reaction to obtain a mixed solution containing zinc carboxylate;

[0054] (2) the mixed solution containing zinc carboxylate obtained in step (1) was stirred and mixed with 1.2 g of lauric acid, heated to reflux at 75° C. and stirred vigorously (2000 r / min) for 2 h to carry out a modification reaction, filtered to obtain a solid, washed with acetone, and dried to obtain an acid-modified zinc carboxylate catalyst;

[0055] The XRD pattern of the acid-modified zinc carboxylate catalyst prepared in this example is as follows: Figure 1 As shown, the IR diagram is Figure 2 shown.

[0056] Example 2

[0057] A method for preparing an acid-modified zinc carboxylate catalyst comprises the following steps:

[0058] (1) 40.82 g of zinc oxide and 500 mL of toluene were stirred to obtain a zinc oxide dispersion, 65 g of glutaric acid was stirred to mix with the zinc oxide dispersion, and the mixture was heated to reflux at 30° C. with vigorous stirring (2000 r / min) for 3 h to perform a double decomposition reaction to obtain a mixed solution containing zinc carboxylate;

[0059] (2) The zinc carboxylate mixed solution obtained in step (1) was stirred and mixed with 19.58 g of lauric acid, heated to reflux at 75° C. and stirred vigorously (2000 r / min) for 2 h to carry out a modification reaction, and a solid was obtained by filtration, which was washed with acetone and dried to obtain an acid-modified zinc carboxylate catalyst.

[0060] Example 3

[0061] A method for preparing an acid-modified zinc carboxylate catalyst comprises the following steps:

[0062] (1) 8.139 g of zinc oxide and 200 mL of toluene were stirred to obtain a zinc oxide dispersion, 12.936 g of glutaric acid was stirred to mix with the zinc oxide dispersion, and the mixture was heated to reflux at 45° C. with vigorous stirring (2000 r / min) for 3 h to perform a double decomposition reaction to obtain a mixed solution containing zinc carboxylate;

[0063] (2) The zinc carboxylate mixed solution obtained in step (1) is stirred and mixed with 1.2 g of lauric acid and 0.5 mL of a 6 mol / L hydrochloric acid solution, heated to reflux at 75° C. and stirred vigorously (2000 r / min) for 2 h to carry out a modification reaction, and a solid is obtained by filtration, washed with acetone, and dried to obtain an acid-modified zinc carboxylate catalyst.

[0064] Example 4

[0065] A method for preparing an acid-modified zinc carboxylate catalyst comprises the following steps:

[0066] (1) 8.139 g of zinc oxide and 200 mL of toluene were stirred to obtain a zinc oxide dispersion, 12.936 g of glutaric acid was stirred to mix with the zinc oxide dispersion, and the mixture was heated to reflux at 45° C. with vigorous stirring (2000 r / min) for 3 h to perform a double decomposition reaction to obtain a mixed solution containing zinc carboxylate;

[0067] (2) The zinc carboxylate mixed solution obtained in step (1) was mixed with 1.3 g of tridecanoic acid and 0.5 mL of 6 mol / L hydrochloric acid solution, heated to reflux at 75° C. and stirred vigorously (2000 r / min) for 2 h to carry out a modification reaction, and a solid was obtained by filtration, washed with acetone, and dried to obtain an acid-modified zinc carboxylate catalyst.

[0068] Comparative Example 1

[0069] A method for preparing a zinc carboxylate catalyst comprises: stirring and mixing 8.139 g of zinc oxide and 200 mL of toluene to obtain a zinc oxide dispersion, stirring and mixing 12.936 g of glutaric acid and the zinc oxide dispersion, heating and reflux at 45° C. with vigorous stirring (2000 r / min) for 5 h to perform a double decomposition reaction, filtering to obtain a solid, washing with acetone, and drying the obtained solid to obtain a zinc carboxylate;

[0070] The XRD pattern of the zinc carboxylate catalyst prepared in this comparative example is as follows Figure 1 As shown, the IR diagram is Figure 2 As shown. Figure 1 It can be seen that the diffraction peaks of the acid-modified zinc carboxylate are consistent with those of the unmodified zinc carboxylate, indicating that the overall crystal structure of the zinc carboxylate remains unchanged during the acid modification process. XRD analysis shows that the crystallinity of the acid-modified zinc carboxylate is increased. Figure 2 It was further confirmed that the structural framework of zinc carboxylate was still maintained after the acid treatment process, but the characteristic peaks of antisymmetric stretching and symmetric stretching of carboxylate functional groups (1537 cm -1 and 1405 cm -1 ) The peak ratio showed a significant change, indicating that the carboxylic acid modifier may partially change the coordination environment of metallic zinc on the catalyst surface.

[0071] Comparative Example 2

[0072] A method for preparing a zinc carboxylate catalyst comprises the following steps: mixing 40.82 g of zinc oxide and 500 mL of toluene under stirring to obtain a zinc oxide dispersion, mixing 65 g of glutaric acid with the zinc oxide dispersion under stirring, heating under reflux at 30° C. with vigorous stirring (2000 r / min) for 5 h to perform a double decomposition reaction, filtering to obtain a solid, washing with acetone, and drying the obtained solid to obtain a zinc carboxylate.

[0073] Application Example 1

[0074] A method for preparing propylene carbonate: adding 0.1 g of the acid-modified zinc carboxylate catalyst prepared in Example 1 to a reactor, vacuum heating at 105° C. for 12 h, then passing propylene oxide (10 mL) pre-treated at 105° C. for 12 h into a high-pressure reactor, and passing CO 2 The pressure in the autoclave was 4MPa, and the temperature was raised to 60°C under stirring to start the reaction. The reaction pressure was controlled at 4MPa and the reaction time was 15h. During the reaction, stirring was continued to ensure that the materials were fully mixed; after the reaction was completed, the remaining gas was discharged, an appropriate amount of dichloromethane was added to dissolve the viscous material product, and acidic methanol was added to precipitate the product. The precipitated product was vacuum dried at 80°C to obtain polypropylene carbonate.

[0075] Application Example 2

[0076] A method for preparing propylene carbonate: adding 0.1 g of the acid-modified zinc carboxylate catalyst prepared in Example 2 to a reactor, vacuum heating at 105°C for 12 h, then passing propylene oxide (10 mL) pre-treated at 105°C for 12 h into a high-pressure reactor, and passing CO 2 The pressure in the autoclave was 4MPa, and the temperature was raised to 60°C under stirring to start the reaction. The reaction pressure was controlled at 4MPa and the reaction time was 15h. During the reaction, stirring was continued to ensure that the materials were fully mixed; after the reaction was completed, the remaining gas was discharged, an appropriate amount of dichloromethane was added to dissolve the viscous material product, and acidic methanol was added to precipitate the product. The precipitated product was vacuum dried at 80°C to obtain polypropylene carbonate.

[0077] Comparative application example 1

[0078] A method for preparing propylene carbonate: adding 0.1 g of zinc carboxylate prepared in Comparative Example 1 to a reaction kettle, vacuuming and heating at 105° C. for 12 h, then passing propylene oxide (10 mL) pre-treated at 105° C. for 12 h into a high-pressure reaction kettle, and passing CO 2The pressure in the autoclave was 4MPa, and the temperature was raised to 85°C under stirring to start the reaction. The reaction pressure was controlled at 4MPa and the reaction time was 30h. During the reaction, stirring was continued to ensure that the materials were fully mixed; after the reaction was completed, the remaining gas was discharged, an appropriate amount of dichloromethane was added to dissolve the viscous material product, and acidic methanol was added to precipitate the product. The precipitated product was vacuum dried at 80°C to obtain polypropylene carbonate.

[0079] Comparative Application Example 2

[0080] A method for preparing propylene carbonate: adding 0.1 g of zinc carboxylate prepared in Comparative Example 2 to a reaction kettle, vacuuming and heating at 105° C. for 12 h, then passing propylene oxide (10 mL) pre-treated at 105° C. for 12 h into a high-pressure reaction kettle, and passing CO 2 The pressure in the autoclave was 4MPa, and the temperature was raised to 85°C under stirring to start the reaction. The reaction pressure was controlled at 4MPa and the reaction time was 30h. During the reaction, stirring was continued to ensure that the materials were fully mixed; after the reaction was completed, the remaining gas was discharged, an appropriate amount of dichloromethane was added to dissolve the viscous material product, and acidic methanol was added to precipitate the product. The precipitated product was vacuum dried at 80°C to obtain polypropylene carbonate.

[0081] Application Example 3

[0082] A method for preparing polycyclohexylene carbonate: the difference from Application Example 1 is that cyclohexyl oxide is used instead of propylene oxide, and the other parameters are the same as those of Application Example 1.

[0083] Application Example 4

[0084] A method for preparing polycyclohexylene carbonate: the difference from Application Example 2 is that cyclohexyl oxide is used instead of propylene oxide, and the other parameters are the same as those of Application Example 2.

[0085] Comparative Application Example 3

[0086] A method for preparing polycyclohexylene carbonate: the difference from comparative application example 1 is that cyclohexene oxide is used instead of propylene oxide, and the other parameters are the same as those of comparative application example 1.

[0087] Comparative Application Example 4

[0088] A method for preparing polycyclohexylene carbonate: the difference from comparative application example 2 is that cyclohexene oxide is used instead of propylene oxide, and the other parameters are the same as those of comparative application example 2.

[0089] Application Example 5

[0090] A method for preparing propylene carbonate: adding 0.1 g of the acid-modified zinc carboxylate catalyst prepared in Example 3 to a reaction kettle, vacuum heating at 105°C for 12 h, then passing propylene oxide (10 mL) pre-treated at 105°C for 12 h into a high-pressure reaction kettle, and passing CO 2 The pressure in the autoclave was 4MPa, and the temperature was raised to 60°C under stirring to start the reaction. The reaction pressure was controlled at 4MPa and the reaction time was 15h. During the reaction, stirring was continued to ensure that the materials were fully mixed; after the reaction was completed, the remaining gas was discharged, an appropriate amount of dichloromethane was added to dissolve the viscous material product, and acidic methanol was added to precipitate the product. The precipitated product was vacuum dried at 80°C to obtain polypropylene carbonate.

[0091] Application Example 6

[0092] A method for preparing propylene carbonate: adding 0.1 g of the acid-modified zinc carboxylate catalyst prepared in Example 4 to a reactor, vacuuming and heating at 105° C. for 12 h, then passing propylene oxide (10 mL) pre-treated at 105° C. for 12 h into a high-pressure reactor, and passing CO 2 The pressure in the autoclave was 4MPa, and the temperature was raised to 60°C under stirring to start the reaction. The reaction pressure was controlled at 4MPa and the reaction time was 15h. During the reaction, stirring was continued to ensure that the materials were fully mixed; after the reaction was completed, the remaining gas was discharged, an appropriate amount of dichloromethane was added to dissolve the viscous material product, and acidic methanol was added to precipitate the product. The precipitated product was vacuum dried at 80°C to obtain polypropylene carbonate.

[0093] Test Case

[0094] The synthesis results of the catalysts prepared in Examples 1-4 and Comparative Examples 1-2 are shown in Table 1.

[0095] Table 1 Catalyst synthesis results of Examples 1 to 4 and Comparative Examples 1 to 2

[0096]

[0097] The test results of application examples 1 to 6 and comparative application examples 1 to 4 are shown in Table 2.

[0098] Table 2 Test results of application examples 1 to 6 and comparative application examples 1 to 4

[0099]

[0100] It can be seen from the above results that the acid-modified zinc carboxylate catalyst prepared by the present invention only requires 15 hours at the same reaction temperature. The present invention represents the activity of the catalyst in terms of the product produced per gram of catalyst. As can be seen from Table 2, when preparing PPC, the activity of the acid-modified zinc carboxylate catalyst prepared in Example 1 is 85g / g, the activity of the acid-modified zinc carboxylate catalyst prepared in Example 2 is 82g / g, the activity of the acid-modified zinc carboxylate catalyst prepared in Example 3 is 91g / g, and the activity of the acid-modified zinc carboxylate catalyst prepared in Example 4 is 90g / g; the activity of the catalyst prepared in Comparative Example 1 is 19g / g, and the activity of the catalyst prepared in Comparative Example 2 is 11g / g. When preparing PCHC, the activity of the acid-modified zinc carboxylate catalyst prepared in Example 1 is 32g / g, the activity of the acid-modified zinc carboxylate catalyst prepared in Example 2 is 31g / g, the activity of the catalyst prepared in Comparative Example 1 is 5g / g, and the activity of the catalyst prepared in Comparative Example 2 is 4g / g. It can be seen that the acid-modified zinc carboxylate catalyst prepared by the present invention can significantly reduce the time of the polymerization reaction compared to the unmodified zinc carboxylate, solves the problem of long reaction time of zinc carboxylate as a catalyst, and the prepared catalyst has excellent catalytic activity, which makes the catalyst prepared by the present invention significantly reduce the use cost when it is industrially applied, and is suitable for industrial catalytic preparation of polypropylene carbonate or polycyclohexylene carbonate. The catalyst prepared by the present invention has this advantage because the preparation method provided by the present invention modifies the zinc carboxylate by acid, which can reduce the particle size of the zinc carboxylate on the one hand, expose the active sites on the surface of the zinc carboxylate, and improve the catalytic activity; on the other hand, the acidic modifier can corrode the surface of the zinc carboxylate, expose more active sites, and improve the catalytic activity; in addition, the zinc carboxylate activity is low, and the acidic modifier can change the structure of the zinc carboxylate, so that the binding force between the hydroxyl group and the zinc carboxylate is reduced, so that the acid-modified zinc carboxylate catalyst is used to prepare the catalyst of polypropylene carbonate and polycyclohexylene carbonate. It is easier to participate in the reaction of epoxy, significantly reducing the time of the catalytic reaction. In addition, the method provided by the present invention is simple to operate, does not require expensive equipment and reagents, has a low modification cost, can significantly reduce the preparation cost of the catalyst, and is conducive to the industrial application of the acid-modified zinc carboxylate catalyst.

[0101] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A method for preparing an acid-modified zinc carboxylate catalyst, comprising the following steps: (1) mixing zinc oxide, a dicarboxylic acid and a solvent, and performing a double decomposition reaction to obtain a mixed solution containing zinc carboxylate; (2) mixing the mixed solution containing zinc carboxylate obtained in step (1) with an acidic modifier to carry out a modification reaction to obtain an acid-modified zinc carboxylate catalyst; The dicarboxylic acid in step (1) is glutaric acid; In the step (2), the acidic modifier is tridecanoic acid and an inorganic acid; The inorganic acid is dilute hydrochloric acid or dilute phosphoric acid, and the concentration of the dilute hydrochloric acid or dilute phosphoric acid is 5-6 mol / L; The molar ratio of the zinc oxide in step (1) to the acidic modifier in step (2) is 12:(0.2-2).

2. The preparation method according to claim 1, characterized in that: In the step (1), the molar ratio of zinc oxide to dicarboxylic acid is 1:(0.9-0.98).

3. The preparation method according to claim 1, characterized in that: The temperature of the metathesis reaction in step (1) is 20-45° C., and the time of the metathesis reaction is 7-8 hours.

4. The preparation method according to claim 1, characterized in that: The temperature of the modification reaction in step (2) is 70-80° C., and the time of the modification reaction is 2-3 hours.

5. The acid-modified zinc carboxylate catalyst prepared by the preparation method according to any one of claims 1 to 4.

6. Use of the acid-modified zinc carboxylate catalyst according to claim 5 as a catalyst for preparing polypropylene carbonate or polycyclohexylene carbonate.

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