Loaded polyphenol zinc catalyst and preparation method thereof

Abstract

The invention discloses a loaded polyphenol zinc catalyst and a preparation method thereof, which can effectively solve the problem of caking in the production process of a zinc gallate catalyst, and meanwhile, the catalyst has a larger specific surface area due to loading. The prepared supported polyphenol zinc catalyst has higher catalytic activity, the catalyst is not agglomerated in the preparation process and is easy for industrial production, the produced catalyst can be directly used for polymerization without being crushed, and the damage to the catalyst in the processing process can be avoided, so that the polyphenol zinc salt catalyst is possibly applied in industry.

Description

Technical Field

[0001] The invention belongs to the technical field of catalyst preparation, and in particular relates to a supported polyphenol zinc catalyst and a preparation method thereof. Background Art

[0002] As the white pollution caused by traditional plastics becomes increasingly serious, degradable plastics are attracting more and more attention. At the same time, as carbon dioxide, the main greenhouse gas, increases in environmental protection requirements, its comprehensive utilization has also become an important issue. These make polypropylene carbonate (PPC), which can combine the two, have a high production value.

[0003] Catalysts play a vital role in the industrial production of PPC. Currently, the catalysts used in industrial production mainly include rare earth ternary catalysts, bimetallic catalysts and dicarboxylic zinc catalysts. Among them, rare earth ternary catalysts and dicarboxylic zinc catalysts have low activity. A dicarboxylic zinc catalyst disclosed in Chinese patent Zl 201510859248.8 has high activity, but the highest activity is only about 18.9 g-PPC / (g-cat·h). Although bimetallic catalysts have high reaction activity, the carbonate unit content of the product is low, generally difficult to reach more than 90%, which has a certain impact on product performance.

[0004] Yongmoon Yang et al. reported a zinc gallate catalyst with a catalytic activity of up to 73.5 g-PPC / (g-cat·h), and the prepared polymer carbonate unit content is generally above 97%. Although this catalyst has excellent performance, the polymerization time is relatively long, generally more than 20 hours, and it will agglomerate during the production process, which is difficult to separate and dry, making it difficult to mass produce. The produced catalyst must be crushed before it can be used for polymerization, and excessive crushing will damage the catalytic activity of the catalyst. Summary of the invention

[0005] The purpose of this section is to summarize some aspects of embodiments of the present invention and briefly introduce some preferred embodiments. Some simplifications or omissions may be made in this section and the specification abstract and the invention title of this application to avoid blurring the purpose of this section, the specification abstract and the invention title, and such simplifications or omissions cannot be used to limit the scope of the present invention.

[0006] In view of the above problems and / or the problems existing in the prior art, the present invention is proposed.

[0007] Therefore, the object of the present invention is to overcome the deficiencies in the prior art and provide a method for preparing a supported polyphenol zinc catalyst.

[0008] In order to solve the above technical problems, the present invention provides the following technical solution: a method for preparing a supported polyphenol zinc catalyst, characterized in that: comprising:

[0009] Carrier activation: Add the catalyst carrier and polyphenol into an alcohol solvent and stir to activate them to form a carrier dispersion;

[0010] Preparation of complex: adding zinc salt and nitrogen-containing compound into alcohol solvent, stirring and reacting to form complex solution;

[0011] Catalyst loading: adding the complex solution into the carrier dispersion and stirring for reaction, so that the complex is loaded on the carrier, collecting the reaction solid and drying it to obtain the loaded polyphenol zinc catalyst.

[0012] As a preferred embodiment of the preparation method of the present invention, the polyphenol is at least one of gallic acid and pyrogallol.

[0013] As a preferred embodiment of the preparation method of the present invention, the catalyst carrier is at least one of silicon dioxide, silica gel, white carbon black, alumina and activated carbon; and the zinc salt is at least one of zinc chloride, zinc nitrate, zinc acetate and zinc sulfate.

[0014] As a preferred embodiment of the preparation method of the present invention, the mass ratio of the catalyst carrier to the zinc contained in the zinc salt is 2 to 10:1.

[0015] As a preferred embodiment of the preparation method of the present invention, the alcohol solvent is one or more of methanol, ethanol, ethylene glycol and n-butanol.

[0016] As a preferred embodiment of the preparation method of the present invention, the nitrogen-containing compound is at least one of ammonia water, diethylamine, triethylamine, pentamethylenediamine, hexamethylenediamine, pyrrole and pyridine.

[0017] As a preferred embodiment of the preparation method of the present invention, the molar ratio of the polyphenol, the nitrogen-containing compound and the zinc contained in the zinc salt is 0.4-0.7:1.8-2.2:1.

[0018] As a preferred embodiment of the preparation method of the present invention, the carrier activation time is 20 to 90 minutes, the complex reaction time is 5 to 60 minutes, and the loading reaction time is 20 to 120 minutes.

[0019] Another object of the present invention is to overcome the deficiencies in the prior art and provide an application of a supported polyphenol zinc catalyst.

[0020] As a preferred embodiment of the present invention, the catalytic activity of the polyphenol zinc catalyst can reach 233.8 g-PPC / (g-cat·h)

[0021] Beneficial effects of the present invention:

[0022] (1) In the process of carrier activation, the present invention allows the polyphenol to fully react with the carrier to activate, so that the catalyst can be loaded on the carrier faster and more evenly, and the loading rate of the catalyst can be improved; the separate preparation of the complex can allow the nitrogen-containing compound to form a complex with the zinc salt according to molecular weight, greatly reducing the amount of the nitrogen-containing compound, making it easier to recycle the alcohol solvent in production, and at the same time, because the coordination compound has better solubility in the alcohol solvent, the amount of alcohol solvent used in the production process can also be reduced.

[0023] (2) The supported catalyst provided by the present invention has an activity of up to 233.8 g-PPC / (g-cat·h), which is 218% higher than similar catalysts reported in the literature. In addition, the catalyst will not agglomerate during the synthesis process. The obtained catalyst can greatly shorten the polymerization reaction time when used for the polymerization of carbon dioxide copolymers. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for describing the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative labor. Among them:

[0025] Figure 1 This is a scanning electron microscope image of the supported polyphenol zinc catalyst prepared in Example 1 of the present invention;

[0026] Figure 2 is an X-ray diffraction spectrum of the supported polyphenol zinc catalyst prepared in Example 2 of the present invention;

[0027] Figure 3 This is the hydrogen nuclear magnetic spectrum of the carbon dioxide copolymer synthesized catalytically by the supported polyphenol zinc catalyst prepared in Example 2 of the present invention.

[0028] Figure 4 This is a scanning electron microscope image of the unloaded catalyst prepared in Comparative Example 1 of the present invention. DETAILED DESCRIPTION

[0029] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the specific implementation methods of the present invention are described in detail below in conjunction with the embodiments of the specification.

[0030] In the following description, many specific details are set forth to facilitate a full understanding of the present invention, but the present invention may also be implemented in other ways different from those described herein, and those skilled in the art may make similar generalizations without violating the connotation of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed below.

[0031] Secondly, the term "one embodiment" or "embodiment" as used herein refers to a specific feature, structure, or characteristic that may be included in at least one implementation of the present invention. The term "in one embodiment" that appears in different places in this specification does not necessarily refer to the same embodiment, nor does it refer to a separate or selective embodiment that is mutually exclusive with other embodiments.

[0032] The raw materials used in the embodiments of the present invention are all commercially available.

[0033] The instruments used in the embodiments of the present invention include: DF-101S magnetic stirrer produced by Shanghai Yukang Science and Education Instrument Co., Ltd., SMF-50 high-pressure reactor produced by Dalian Jingyi Reactor Co., Ltd., Bruker Advance III-400 nuclear magnetic resonance spectrometer, and Mettler-Toledo XSR204 electronic balance.

[0034] The catalytic activity calculation method in the embodiment of the present invention is shown in the following formula:

[0035] Catalytic activity = copolymer mass / zinc gallate mass / reaction time.

[0036] In the embodiment of the present invention, the carbonate unit content is calculated from the peak areas of chemical shifts 5.0 and 3.4-3.8 in the hydrogen nuclear magnetic spectrum, and the carbonate unit percentage content = 3*A5.0 / (3*A5.0+A3.4-3.8)*100.

[0037] Example 1

[0038] (1) Add 30 mL of methanol, 1 g of gallic acid, and 3 g of white carbon black into a 100 mL conical flask and stir magnetically for 30 min.

[0039] (2) Add 20 mL of methanol and 2.2 g of zinc acetate to a 50 mL conical flask, stir magnetically to disperse evenly, then add 1.6 g of pyrrole and stir for 30 min.

[0040] (3) The zinc acetate complex solution was added to the silica dispersion under magnetic stirring, and then stirred for reaction for 30 minutes. After the reaction was completed, the solid was separated by centrifugation and vacuum dried at room temperature for 12 hours to obtain 5 g of a powdered catalyst.

[0041] (4) 0.025 g of the above catalyst (containing 0.01 g of zinc gallate) and 20 mL of pre-dehydrated propylene oxide were added to a 50 mL autoclave, and the mixture was stirred and reacted at 80° C. under a carbon dioxide pressure of 4.5 MPa for 8 h. The reaction mixture was discharged and placed in a vacuum oven at 50° C. for 48 h to obtain 18.7 g of a carbon dioxide-propylene oxide copolymer. The catalytic activity was 233.8 g-PPC / (g-cat·h) based on zinc gallate. 1 The content of carbonate units in the carbon dioxide-propylene oxide copolymer was determined by H-NMR and was found to be 98.6%.

[0042] Example 2

[0043] (1) Add 50 mL of methanol, 1 g of gallic acid, and 5 g of white carbon black into a 100 mL conical flask and stir magnetically for 1 h.

[0044] (2) Add 20 mL of methanol and 1.6 g of zinc chloride to a 50 mL conical flask. After the mixture is dispersed evenly by magnetic stirring, add 1 g of ammonia water and stir for 1 h after the ammonia water is added.

[0045] (3) The zinc chloride complex solution was added to the silica dispersion under magnetic stirring, and then stirred for reaction for 1 hour. After the reaction was completed, the solid was separated by centrifugation and vacuum dried at room temperature for 24 hours to obtain 6.81 g of a powdered catalyst.

[0046] (4) 0.038 g of the above catalyst (containing 0.01 g of zinc gallate) and 20 mL of pre-dehydrated propylene oxide were added to a 50 mL autoclave, and the mixture was stirred and reacted at 80° C. under a carbon dioxide pressure of 4.5 MPa for 8 h. The reaction mixture was discharged and placed in a vacuum oven at 50° C. for 48 h to obtain 13.2 g of a carbon dioxide-propylene oxide copolymer, the catalytic activity of which was 165 g-PPC / (g-cat·h) based on zinc gallate. 1 The content of carbonate units in the carbon dioxide-propylene oxide copolymer was determined by H-NMR and was found to be 96.2%.

[0047] Example 3

[0048] (1) Add 50 mL of ethanol, 1 g of gallic acid, and 5 g of activated carbon to a 100 mL conical flask and stir magnetically for 1 h.

[0049] (2) Add 20 mL of ethanol and 2.3 g of zinc nitrate to a 50 mL conical flask, stir magnetically to disperse evenly, then add 1.9 g of diethylamine and stir for 5 min.

[0050] (3) The zinc nitrate complex solution was added to the activated carbon dispersion under magnetic stirring, and then stirred for reaction for 2 h. After the reaction was completed, the solid was separated by centrifugation and vacuum dried at room temperature for 24 h to obtain 7.1 g of a powdered catalyst.

[0051] (4) 0.035 g of the above catalyst (containing 0.01 g of zinc gallate) and 20 mL of pre-dehydrated propylene oxide were added to a 50 mL autoclave, and the mixture was stirred and reacted at 80° C. under a carbon dioxide pressure of 4.5 MPa for 8 h. The reaction mixture was discharged and placed in a vacuum oven at 50° C. for 48 h to obtain 15.6 g of a carbon dioxide-propylene oxide copolymer, the catalytic activity of which was 195 g-PPC / (g-cat·h) based on zinc gallate. 1 The carbonate unit content in the carbon dioxide-propylene oxide copolymer was determined by H-NMR and was found to be 94.8%.

[0052] Example 4

[0053] (1) Add 30 mL of ethylene glycol, 1 g of gallic acid, and 3 g of white carbon black into a 100 mL conical flask and stir magnetically for 30 min.

[0054] (2) Add 20 mL of ethanol and 1.9 g of zinc sulfate to a 50 mL conical flask, stir magnetically to disperse evenly, then add 1.5 g of hexamethylenediamine and stir for 5 min.

[0055] (3) The zinc sulfate complex solution was added to the silica dispersion under magnetic stirring, and then stirred for reaction for 2 h. After the reaction was completed, the solid was separated by centrifugation and vacuum dried at room temperature for 24 h to obtain 4.9 g of a powdered catalyst.

[0056] (4) 0.025 g of the above catalyst (containing 0.01 g of zinc gallate) and 20 mL of pre-dehydrated propylene oxide were added to a 50 mL autoclave, and the mixture was stirred and reacted at 80° C. under a carbon dioxide pressure of 4.5 MPa for 8 h. The reaction mixture was discharged and placed in a vacuum oven at 50° C. for 48 h to obtain 7.3 g of a carbon dioxide-propylene oxide copolymer. The catalytic activity was 91.2 g-PPC / (g-cat·h) based on zinc gallate. 1 The content of carbonate units in the carbon dioxide-propylene oxide copolymer was determined by H-NMR and found to be 95.1%.

[0057] Example 5

[0058] (1) Add 30 mL of n-butanol, 1 g of gallic acid, and 3 g of activated carbon into a 100 mL conical flask and stir magnetically for 1 h.

[0059] (2) Add 20 mL of methanol and 1.9 g of zinc sulfate to a 50 mL conical flask, stir magnetically to disperse evenly, then add 2 g of pyridine and stir for 5 min.

[0060] (3) The zinc sulfate complex solution was added to the activated carbon dispersion under magnetic stirring, and then stirred for reaction for 2 h. After the reaction was completed, the solid was separated by centrifugation and vacuum dried at room temperature for 24 h to obtain 5.5 g of a powdered catalyst.

[0061] (4) 0.022 g of the above catalyst (containing 0.01 g of zinc gallate) and 20 mL of pre-dehydrated propylene oxide were added to a 50 mL autoclave, and the mixture was stirred and reacted at a carbon dioxide pressure of 4.5 MPa and 80° C. for 8 h. The reaction mixture was discharged and placed in a vacuum oven at 50° C. for 48 h to obtain 6.7 g of carbon dioxide-propylene oxide copolymer, with a catalytic activity of 83.8 g-PPC / (g-cat·h) based on zinc gallate. 1 The content of carbonate units in the carbon dioxide-propylene oxide copolymer was determined by H-NMR and was found to be 93.3%.

[0062] Comparative Example 1

[0063] This comparative example provides a method for preparing an unsupported catalyst, comprising the following steps:

[0064] (1) Add 50 mL of methanol, 1 g of gallic acid, and 2.2 g of zinc acetate to a 100 mL conical flask and stir magnetically for 30 min to fully dissolve.

[0065] (2) 1.6 g of pyrrole was slowly added dropwise to the above solution, stirred for 30 min, and the solid was separated by centrifugation. The solid was vacuum dried at room temperature for 12 h to obtain 2.2 g of bulk catalyst. The catalyst was ground into powder in a mortar and vacuum dried at room temperature for 5 h to obtain 2.19 g of powdered catalyst.

[0066] (3) 0.01 g of the above catalyst was added to a 50 mL autoclave, and 20 mL of propylene oxide from which water had been previously removed was added. The mixture was stirred and reacted at a carbon dioxide pressure of 4.5 MPa and 80° C. for 8 h. The reaction mixture was discharged and placed in a vacuum oven at 50° C. for 48 h to obtain 6.9 g of a carbon dioxide-propylene oxide copolymer having a catalytic activity of 86.2 g-PPC / (g-cat·h). The carbonate unit content in the carbon dioxide-propylene oxide copolymer was determined by 1H-NMR to be 95.8%.

[0067] like Figure 4 As shown, the unsupported catalyst exhibited brittle fracture of large pieces of catalyst after drying and grinding.

[0068] Comparative Example 2

[0069] (1) Add 30 mL of methanol, 1 g of pyrogallol, and 3 g of alumina into a 100 mL conical flask and stir magnetically for 30 min.

[0070] (2) Add 20 mL of methanol and 3 g of zinc acetate to a 50 mL conical flask, stir magnetically to disperse evenly, then add 2.2 g of pyrrole and stir for 30 min.

[0071] (3) The zinc acetate complex solution was added to the alumina dispersion under magnetic stirring, and then stirred for reaction for 30 minutes. After the reaction was completed, the solid was separated by centrifugation and vacuum dried at room temperature for 12 hours to obtain 4.7 g of a powdered catalyst.

[0072] (4) 0.28 g of the above catalyst (containing 0.1 g of zinc gallate) and 20 mL of pre-dehydrated propylene oxide were added to a 50 mL autoclave, and the mixture was stirred and reacted at a carbon dioxide pressure of 4.5 MPa and 80° C. for 8 h. The reaction mixture was discharged and placed in a vacuum oven at 50° C. for 48 h to obtain 3.8 g of carbon dioxide-propylene oxide copolymer, with a catalytic activity of 4.8 g-PPC / (g-cat·h) based on zinc gallate. 1 The content of carbonate units in the carbon dioxide-propylene oxide copolymer was determined by H-NMR and found to be 97.3%.

[0073] Comparative Example 3

[0074] The difference between this comparative example and Example 1 is that the masses of gallic acid and pyrrole in step (2) are replaced by 0.7 g and 1.3 g respectively, and the remaining steps are the same as those in Example 1, and finally 1.7 g of carbon dioxide-propylene oxide copolymer is obtained, and the catalytic activity is 21.2 g-PPC / (g-cat·h) calculated as zinc gallate. The carbonate unit content in the carbon dioxide-propylene oxide copolymer is 97.7% as determined by 1H-NMR.

[0075] Comparative Example 4

[0076] The difference between this comparative example and Example 1 is that the masses of gallic acid and pyrrole in step (2) are replaced by 1.6 g and 1.9 g respectively, and the remaining steps are the same as those in Example 1, and finally 1.2 g of carbon dioxide-propylene oxide copolymer is obtained, and the catalytic activity is 15 g-PPC / (g-cat·h) calculated as zinc gallate. The carbonate unit content in the carbon dioxide-propylene oxide copolymer is 90.3% as determined by 1H-NMR.

[0077] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solutions of the present invention can be modified or replaced by equivalents without departing from the spirit and scope of the technical solutions of the present invention, which should all be included in the scope of the present invention.

Claims

1. A method for preparing a supported polyphenol zinc catalyst, characterized in that: include, Carrier activation: Add the catalyst carrier and polyphenol into an alcohol solvent and stir to activate them to form a carrier dispersion; Preparation of complex: adding zinc salt and nitrogen-containing compound into alcohol solvent, stirring and reacting to form complex solution; Catalyst loading: adding the complex solution into the carrier dispersion and stirring for reaction, so that the complex is loaded on the carrier, collecting the reaction solid and drying it to obtain the loaded polyphenol zinc catalyst.

2. The preparation method according to claim 1, characterized in that: The polyphenol is at least one of gallic acid and pyrogallol.

3. The preparation method according to claim 1, characterized in that: The catalyst carrier is at least one of silicon dioxide, silica gel, white carbon black, aluminum oxide and activated carbon; the zinc salt is at least one of zinc chloride, zinc nitrate, zinc acetate and zinc sulfate.

4. The preparation method according to claim 3, characterized in that: The mass ratio of the catalyst carrier to the zinc contained in the zinc salt is 2 to 10:

1.

5. The preparation method according to claim 1, characterized in that: The alcohol solvent is one or more of methanol, ethanol, ethylene glycol and n-butanol.

6. The preparation method according to claim 1, characterized in that: The nitrogen-containing compound is at least one of ammonia, diethylamine, triethylamine, pentamethylenediamine, hexamethylenediamine, pyrrole and pyridine.

7. The preparation method according to claim 1, characterized in that: The molar ratio of the polyphenol, the nitrogen-containing compound and the zinc contained in the zinc salt is 0.4-0.7:1.8-2.2:

1.

8. The preparation method according to claim 1, characterized in that: The carrier activation time is 20 to 90 minutes, the complex reaction time is 5 to 60 minutes, and the loading reaction time is 20 to 120 minutes.

9. The supported polyphenol zinc catalyst prepared by the preparation method according to any one of claims 1 to 8.

10. The use of the supported polyphenol zinc catalyst as claimed in claim 9, characterized in that: The catalytic activity of the polyphenol zinc catalyst can reach 233.8 g-PPC / (g-cat·h).

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