Catalyst for alkoxylation reaction and preparation method thereof

Abstract

The invention discloses a catalyst for alkoxylation reaction and a preparation method thereof, the catalyst for alkoxylation reaction comprises a ZIF modified material, and the ZIF modified material is prepared by calcining a ZIF material. The catalyst for alkoxylation reaction and the preparation method thereof have the advantages that the reaction catalytic activity is higher, the residual alcohol content is lower, the molecular weight distribution of the product is narrower, and the synthesis of the catalyst is simpler and quicker.

Description

Technical Field

[0001] The invention belongs to the technical field of catalysts, and particularly relates to a catalyst for alkoxylation reaction and a preparation method thereof. Background Art

[0002] Nonionic surfactants are widely used in textiles, papermaking, cosmetics, and agriculture due to their excellent cleaning, dispersing, emulsifying, foaming, and wetting properties. Ethylene oxide adducts of fatty alcohols derived from natural plant oils and fats, in particular, have long been favored due to their excellent performance, good biodegradability, and minimal environmental impact. Fatty alcohol polyoxyethylene ethers (AEOs) are mixtures of alcohol ethers with varying degrees of polymerization, produced by the action of a catalyst and fatty alcohols and ethylene oxide. Catalysts play an extremely important role in this process, directly influencing product performance, so catalyst selection must be extremely cautious.

[0003] Catalysts used to catalyze the reaction of fatty alcohols and ethylene oxide are called ethoxylation catalysts. They are generally divided into those with a conventional distribution and those with a narrow distribution. Conventional distribution catalysts include KOH, NaOH, and CH3ONa. These catalysts have high catalytic activity and low manufacturing costs, making them widely used in industrial production. The alcohol ether products produced by conventional distribution catalysts contain large amounts of free alcohol and alcohol ethers with high EO adduction numbers. This can cause certain skin irritations to otherwise very mild surfactants. Furthermore, the high EO adduction number of alcohol ethers affects their physicochemical properties. Narrow distribution catalysts, on the other hand, can avoid these problems. Therefore, the relative molecular weight distribution of alcohol ether products is the primary factor affecting product performance. The narrower the product molecular weight distribution, the more optimal the product's utilization. Narrow distribution catalysts typically include alkaline earth metal, Lewis acid, and hydrotalcite catalysts. However, these catalysts still present certain challenges in terms of reaction activity, catalyst reusability, and residual alcohol in the substrate and its distribution.

[0004] The information disclosed in this background technology section is only intended to enhance understanding of the overall background of the invention and should not be regarded as an admission or any form of suggestion that the information constitutes the prior art already known to a person skilled in the art. Summary of the Invention

[0005] The object of the present invention is to provide a catalyst for alkoxylation reaction and a preparation method thereof, which have the advantages of higher reaction catalytic activity, lower residual alcohol and narrower product molecular weight distribution.

[0006] In order to achieve the above object, a specific embodiment of the present invention provides a technical solution as follows: an application of a ZIF modified material in catalytic alkoxylation reaction, wherein the ZIF modified material is prepared by calcining a ZIF material.

[0007] A specific embodiment of the present invention also provides a catalyst for alkoxylation reaction, and the catalyst includes a ZIF modified material.

[0008] A specific embodiment of the present invention also provides a preparation method of a catalyst for alkoxylation reaction, and the preparation method includes the following steps:

[0009] Calcine the ZIF material, and then obtain the catalyst.

[0010] In one or more embodiments of the present invention, the step of calcining the ZIF material includes:

[0011] Heat the ZIF material in an inert atmosphere at a heating rate of 5 - 10 °C / min to 600 - 800 °C, and then continuously calcine for 2.5 - 3.5 h.

[0012] In one or more embodiments of the present invention, the inert atmosphere includes at least one of nitrogen atmosphere, helium atmosphere, and argon atmosphere.

[0013] In one or more embodiments of the present invention, the ZIF material is calcined in a muffle furnace.

[0014] In one or more embodiments of the present invention, the ZIF material is a zeolitic imidazolate framework material.

[0015] In one or more embodiments of the present invention, the preparation steps of the zeolitic imidazolate framework material include:

[0016] Heat and react a mixed system of metal acetate, imidazole ligand, and organic solvent, and obtain the zeolitic imidazolate framework material after the reaction.

[0017] In one or more embodiments of the present invention, the step of obtaining the zeolitic imidazolate framework material after the reaction includes:

[0018] Wash and dry the solid product obtained from the reaction, and obtain the zeolitic imidazolate framework material.

[0019] In one or more embodiments of the present invention, the metal salt includes at least one of zinc salt and cobalt salt;

[0020] The imidazole ligands include at least one of imidazole, 2-methylimidazole, 2-ethylimidazole, 2-nitroimidazole, 1H-imidazol-1-ylacetonitrile, 4,5-dichloroimidazole, 2-imidazolecarboxaldehyde, 3H-imidazo[4,5-b]pyridine, benzimidazole, 3H-imidazo[4,5-c]pyridine, 7H-imidazo[4,5-d]pyrimidine, 5-chlorobenzimidazole, 5-bromobenzimidazole, and 5-nitrobenzimidazole.

[0021] Compared with the prior art, the beneficial effects of the catalyst for alkoxylation reaction and its preparation method of the present invention include:

[0022] (1) The catalyst has higher reaction catalytic activity, lower residual alcohol, and narrower product molecular weight distribution;

[0023] (2) The synthesis of the catalyst is simpler and faster. Description of the Drawings

[0024] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the drawings in the following description are only some embodiments recorded in the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0025] Figure 1 It is the XRD pattern of the ZIF-8 material and the ZIF-8 modified material in Example 1 of the present invention;

[0026] Figures 2a - 2c It is the SEM image of the ZIF-8 material in Example 1 of the present invention at different shooting scales;

[0027] Figure 3a and 3b It is the SEM image and the element distribution map of the ZIF-8 material in Example 1 of the present invention at a certain shooting scale;

[0028] Figure 4 It is the EDS element analysis map of the ZIF-8 material in Example 1 of the present invention at a certain shooting scale;

[0029] Figures 5a - 5d It is the SEM image of the ZIF-8 modified material in Example 1 of the present invention at different shooting scales;

[0030] Figure 6a and 6b It is the SEM image and the element distribution map of the ZIF-8 modified material in Example 1 of the present invention at a certain shooting scale;

[0031] Figure 7EDS elemental analysis diagram of the ZIF-8 modified material in Example 1 of the present invention at a certain shooting scale;

[0032] Figure 8 XPS full spectrum diagram of the ZIF-8 modified material in Example 1 of the present invention;

[0033] Figure 9 Zn2p spectrogram of the ZIF-8 modified material in Example 1 of the present invention

[0034] Figure 10 C1s spectrogram of the ZIF-8 modified material in Example 1 of the present invention;

[0035] Figure 11 N1s spectrogram of the ZIF-8 modified material in Example 1 of the present invention;

[0036] Figure 12 NH3-TPD diagram of the ZIF-8 modified material in Example 1 of the present invention;

[0037] Figure 13 CO2-TPD diagram of the ZIF-8 modified material in Example 1 of the present invention. Detailed implementation manners

[0038] In order to enable those skilled in the art to better understand the technical solutions in the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without making creative efforts shall fall within the protection scope of the present invention.

[0039] As mentioned in the background art, fatty alcohol polyoxyethylene ether is a kind of non-ionic surfactant, which is an alcohol ether mixture with different degrees of polymerization generated by fatty alcohol and ethylene oxide under the action of a catalyst.

[0040] At present, if the above reaction uses an existing catalyst with a conventional distribution, the molecular weight distribution of the final product is relatively wide, and the product contains a large amount of free alcohol and alcohol ethers with a high EO addition number. This results in a certain skin irritation for the originally extremely mild surfactant, and the alcohol ethers with a high EO addition number also affect its physical and chemical properties. The width of the relative molecular weight distribution of the product is the main factor affecting the performance of the product (non-ionic surfactant). The narrower the molecular weight distribution of the product, the more conducive to the rational utilization of the product.

[0041] If the above reaction uses existing narrow-distribution catalysts, such as alkaline earth metal type, Lewis acid type, and hydrotalcite-like catalysts, etc., although the molecular weight distribution of the product can be narrowed, there are still certain problems in terms of reaction activity, catalyst reuse, substrate residual alcohol, and distribution.

[0042] To solve the above problems, the present invention provides an application of a ZIF modified material in the catalytic alkoxylation reaction, and the ZIF modified material is prepared by calcining a ZIF material. When the ZIF modified material of the present invention is used as a catalyst for the catalytic alkoxylation reaction, its reaction catalytic activity is higher, the residual alcohol is lower, and the molecular weight distribution of the product is narrower; moreover, the synthesis of the ZIF modified material is simpler and faster. Calcination can play a role in modifying the ZIF material, and the modified ZIF modified material can be used as a catalyst for the catalytic alkoxylation reaction.

[0043] ZIF material (zeolitic imidazolate framework material) is a porous crystal material with the characteristics of high stability, high porosity, and organic functionality. The ZIF material is a metal-organic framework (MOF) material formed by the self-assembly of zinc or cobalt ions and imidazole ligands, and its structure is similar to that of zeolite, but imidazole ligands are used to replace the oxygen bridges in zeolite.

[0044] Chemical properties and structural characteristics of the ZIF material: The ZIF material has a tetrahedral three-dimensional network structure, similar to zeolite, but zinc or cobalt ions are used instead of silicon, and imidazole ligands are used to replace the oxygen bridges. This structure endows the ZIF material with characteristics such as high specific surface area, high porosity, high thermal stability, and chemical stability. In addition, the pore size of the ZIF material can be adjusted, and the pore walls can be functionalized, further expanding its application range.

[0045] Generally, due to the characteristics of high specific surface area, high porosity, high thermal stability, and chemical stability, the ZIF material is often used as a carrier.

[0046] The present invention also provides a catalyst for the alkoxylation reaction, and the catalyst includes a ZIF modified material.

[0047] In a specific example, fatty alcohol ethers (surfactants) use fatty alcohols as starting materials (including straight-chain or branched-chain fatty alcohols such as C8, C12, C12-C14, C16, etc.), with a catalyst (the catalyst dosage is generally 0.5% - 20% of the substrate mass), the reaction temperature is generally 100 - 200 °C, and the reaction pressure is generally 0.2 - 1.0 MPa, and an epoxide (m = 0 - 6, corresponding epoxides are ethylene oxide, 1,2-epoxypropane... 1,2-epoxyoctane) to carry out the alkoxylation reaction. After the reaction, a fatty alcohol ether product is obtained, and after filtering the catalyst through filter paper, a pure fatty alcohol polyether product is obtained, which can be used for non-ionic surfactants.

[0048] The reaction equation of fatty alcohol alkoxylation is as follows:

[0049]

[0050] Among them, R-OH represents fatty alcohol, n is the degree of polymerization, Rm represents a saturated alkyl group or a hydrogen group, m = 0 - 6, and Cat is the catalyst of the present invention (i.e., the ZIF modified material).

[0051] The ZIF modified material can also be called ZIF-derived porous carbon, which has larger pore diameters and uniform pore distributions, and its average pore diameter is 2.1 nm. Whether it is linear fatty alcohol or ethylene oxide, their molecular diameters do not exceed 0.3 nm. They can freely enter the inner surface of the porous carbon for reaction. However, with the increase in the number of EO additions, the curling of the chain and the formation of hydrogen bonds will reduce the speed of entering the surface of the porous carbon, and the reaction rate constant will decrease. Therefore, at a certain average degree of polymerization, the molecular weight distribution of its products will be narrower than that of the homogeneous catalysts commonly used at present, and the residual alcohol will be lower. On the other hand, the metal Zn and Co present in ZIF are high-valent metals compared with K and Na. After the growing oligoethoxy chains surround the metal ions in the catalyst, further growth will be inhibited to a certain extent due to steric hindrance. Under the combined action of these two reasons, the ZIF-derived porous carbon catalyst will have a narrower distribution of fatty alcohol polyoxyethylene ethers and lower residual alcohol than most of the catalysts currently used.

[0052] In addition, ZIF-derived porous carbon also has both acid and base dual active sites, which can greatly improve the catalytic activity. Its acidic sites come from the Lewis acidity of the unsaturated metal ions on 2-Mim and the proton acid in the -NH group, while the basic sites are provided by N-. Currently, it is known that the acidic sites can act on ethylene oxide to open the ring of ethylene oxide to generate +CH2CH2OH. The reaction rate between +CH2CH2OH and fatty alcohol for chain growth is relatively fast. Therefore, acidic catalysts usually have a higher reaction rate. The basic sites usually act on fatty alcohol to generate RO-, and then initiate the chain with ethylene oxide. Usually, this step has a relatively slow rate. Therefore, basic catalysts usually have an induction period for a certain time. For ZIF-derived porous carbon, these two steps can be carried out together, attacking fatty alcohol and ethylene oxide simultaneously. Therefore, the catalytic activity of ZIF-derived porous carbon is higher than that of single acid catalysis or base catalysis.

[0053] A specific example of the present invention also provides a preparation method of a catalyst for alkoxylation reaction, and the preparation method includes the following steps:

[0054] Calcine the ZIF material, and then obtain the catalyst.

[0055] Specifically, the steps of calcining the ZIF material include:

[0056] The ZIF material is heated to 600-800°C under an inert atmosphere at a heating rate of 5-10°C / min and then calcined for 2.5-3.5 hours. That is, after the temperature reaches 600-800°C, calcination is continued at this temperature for 2.5-3.5 hours. Preferably, the temperature is raised to 600°C and calcined for 3 hours. A calcination temperature of 600°C is optimal. The activity of the ZIF-modified material decreases with increasing temperature. This is because as the calcination temperature increases, the nitrogen content continues to volatilize and decreases, significantly reducing its alkalinity. On the other hand, an increase in calcination temperature can cause the metal to be gradually reduced to a metal element by carbon, or the increase in temperature can cause the metal Zn or cobalt to volatilize, resulting in a significant decrease in Lewis acidity. Therefore, the calcination temperature should not exceed 800°C.

[0057] Specifically, the inert atmosphere includes at least one of a nitrogen atmosphere, a helium atmosphere, and an argon atmosphere.

[0058] Specifically, the ZIF material is calcined in a furnace.

[0059] Specifically, the ZIF material is a zeolite imidazolate framework material.

[0060] Specifically, the preparation steps of the zeolite imidazolate framework structure material include:

[0061] A mixed system of metal acetate, imidazole ligand and organic solvent is heated for reaction, and a zeolite imidazole ester framework structure material is obtained after the reaction.

[0062] Specifically, the steps of obtaining the zeolite imidazolate framework material after the reaction include:

[0063] The solid product obtained by the reaction is washed and dried to obtain a zeolite imidazolate framework structure material.

[0064] Preferably, the solid product obtained by the reaction can be washed three times or more to remove impurities on the surface of the solid product. The washed solid product can be dried in a vacuum drying oven, for example, under vacuum and 150°C for 5 hours to further remove low-boiling point impurities on the surface of the solid product. The vacuum degree, drying temperature, and time can be adjusted according to actual needs.

[0065] Specifically, the metal salt includes at least one of a zinc salt and a cobalt salt. Specifically, the metal salt may be at least one of zinc acetate, cobalt acetate, zinc nitrate and cobalt nitrate.

[0066] The imidazole ligand includes at least one of imidazole, 2-methylimidazole, 2-ethylimidazole, 2-nitroimidazole, 1H-imidazol-1-yl acetonitrile, 4,5-dichloroimidazole, 2-imidazolecarboxaldehyde, 3H-imidazo[4,5-b]pyridine, benzimidazole, 3H-imidazo[4,5-c]pyridine, 7H-imidazole[4,5-d]pyrimidine, 5-chlorobenzimidazole, 5-bromobenzimidazole and 5-nitrobenzimidazole.

[0067] The catalyst and preparation method of the present invention will be described in detail below with reference to specific examples and comparative examples.

[0068] Example 1

[0069] (1) Preparation of ZIF materials

[0070] 2.64 g (12 mmol) of zinc acetate and 2.95 g (36 mmol) of 2-methylimidazole ligand were mixed in 120 mL of methanol solvent and then subjected to hydrothermal reaction in a kettle at 120°C for 3 days to obtain crystals. The resulting crystals were washed three times with fresh solvent and centrifuged to obtain the product, which was then dried in an 80°C oven for 10 hours to obtain the ZIF-8 precursor.

[0071] (2) Preparation of ZIF modified materials

[0072] The ZIF-8 material was calcined at a high temperature of 600-800°C for 3 hours at a heating rate of 5-10°C / min under high-purity nitrogen. After the calcination, the material was naturally cooled to room temperature to obtain the ZIF-8 modified material.

[0073] The ZIF-8 material and the ZIF-8 modified material in this embodiment were scanned using an X-ray diffractometer to obtain the following Figure 1 The XRD pattern shown. Figure 1 It can be seen from the XRD diffraction peak position of the ZIF-8 material we synthesized ( Figure 1 The blue data line in the middle) and the analog data ( Figure 1 The red data line at the bottom) is consistent, proving that pure phase ZIF-8 was successfully synthesized by the solvothermal method. The XRD diffraction peak position of ZIF-8 modified material ( Figure 1 The upper cyan data line) has a different XRD diffraction peak position from that of the ZIF-8 material, indicating that the structure of the ZIF-8 modified material is different from that of the ZIF-8 material. It can be inferred that the different reasons for the structure of the ZIF-8 modified material are caused by the collapse of part of the crystal structure of the ZIF-8 material.

[0074] Figures 2a - 2c SEM images of ZIF-8 materials at different shooting scales, Figure 3a and 3bThe SEM image and element distribution map of ZIF-8 material at 10μm shooting scale, Figure 4 The EDS data of ZIF-8 material at different shooting scales. Figures 2a - 2c From the SEM images of ZIF-8 materials with a shooting scale of 100μm to 20μm, it can be seen that the ZIF-8 material is a three-dimensional dodecahedron, which is consistent with existing literature reports. Figure 3b The element distribution diagram shows the element distribution of C, N, O, and Zn. It can be found that the elements are evenly distributed without agglomeration.

[0075] Figures 5a - 5d SEM images of ZIF-8 modified materials at different shooting scales, Figure 6a and 6b The SEM image and element distribution map of ZIF-8 modified material at 10μm shooting scale, Figure 7 The EDS data of ZIF-8 modified materials at different shooting scales are shown in Figure 2. Figures 5a - 5d From the SEM images of the ZIF-8 modified material from 30μm to 5μm, it can be seen that the ZIF-8 modified material is still in the dodecahedral form, and the size of the ZIF-8 modified material is reduced as a whole (compared to the ZIF-8 material). Figure 6b The element distribution diagram shows the element distribution of C, N, O, and Zn. It can be found that after high-temperature calcination, the elements in the ZIF-8 modified material are still evenly distributed without agglomeration.

[0076] Table 1: EDS element content analysis data of ZIF-8 material and ZIF-8 modified materials

[0077] C(％) N(％) O(％) Zn (%) ZIF-8 material 42.5 19.7 10.5 27.1 ZIF-8 modified material 40.6 24.7 9.3 25.4

[0078] As shown in Table 1, the content of each element in the ZIF-8 modified material obtained after high-temperature calcination of the ZIF-8 material in an inert atmosphere did not change significantly, proving that at this temperature, the partial collapse of the ZIF-8 crystal structure does not lead to a large amount of volatilization of the elements therein.

[0079] Figures 8 - 11XPS spectra of the ZIF-8 modified material and its Zn 2p, C, and N elemental spectra. It can be seen from the full spectrum that the surface of the ZIF-8 modified material consists of C, N, O, and Zn. The Zn 2p spectrum has obvious double peaks at binding energies of 1021.8 and 1044.5 eV, which are Zn 2p3 / 2 and 2p1 / 2. The binding energy distance between the two peaks is 22.7 eV, indicating that the Zn ions in the ZIF-8 modified material are +2 valence, and the coordinatively unsaturated Zn species can bring Lewis acid sites. An obvious single peak (284.8 eV) can be seen in the C spectrum, which is mainly graphite carbon. The N spectrum was deconvoluted and fitted to judge its species in detail, and it was found that it could be decomposed into three N species, namely coordinated Zn-N at 398.4 eV, pyridine N at 398.8 eV, and pyrrole N at 400.7 eV. It is proved that after ZIF-8 is calcined at 600-800 °C, a large number of Zn-N bonds are still retained, and the existing N species can also bring certain basicity.

[0080] Figure 12 , 13 They are the NH3-TPD data and CO2-TPD data of the ZIF-8 modified material respectively. Figure 12 As shown, the ZIF-8 modified material shows three desorption peaks at low temperature (~120 °C), medium temperature (~210 °C and ~260 °C). These peaks can be attributed to the adsorption of NH3 on weak acid sites and medium strong acid sites respectively, proving that the ZIF-8 modified material has certain weak acid and medium strong acid. Figure 13 As shown, the ZIF-8 modified material shows three desorption peaks at low temperature (~100 °C), medium temperature (~290 °C and ~380 °C), and the CO2 is completely desorbed only near 500 °C. These peaks can be attributed to the adsorption of CO2 on weak base sites and medium strong base sites respectively, indicating that the ZIF-8 modified material has certain weak base and medium strong base. And according to the final desorption temperature, it shows that the ZIF-8 modified material has certain strong basic sites.

[0081] Example 2

[0082] 2.64 g (12 mmol) of zinc acetate and 5.77 g (60 mmol) of 2-ethylimidazole ligand were mixed in 100 mL of ethanol solvent, and then crystals were obtained after 1 day at 150 °C in a hydrothermal autoclave. The obtained crystals were washed three times with fresh solvent and then centrifuged to obtain the product, which was dried in an oven at 80 °C for 10 h to obtain the ZIF-14 precursor.

[0083] (2) Preparation of the ZIF modified material

[0084] It was obtained by high-temperature calcination of the ZIF-14 precursor at 600 °C for 3 h with a heating rate of 5 °C / min under high-purity N2. After the calcination was completed, it was naturally cooled to room temperature to obtain ZIF-14-derived porous carbon, which is the ZIF-modified material.

[0085] Example 3

[0086] Dissolve 2.62 g (36 mmol) of cobalt nitrate hexahydrate in 40 ml of methanol, and dissolve 4.43 g (54 mmol) of 2-methylimidazole ligand in 40 mL of methanol solvent. Then mix them and stir continuously at room temperature for 4 h to obtain crystals. The obtained crystals were washed three times with fresh solvent and then centrifuged to obtain the product, which was dried in an 80 °C oven for 10 h to obtain the ZIF-67 precursor.

[0087] (2) Preparation of ZIF-modified material

[0088] It was obtained by high-temperature calcination of the ZIF-67 precursor at 600 °C for 3 h with a heating rate of 5 °C / min under high-purity N2. After the calcination was completed, it was naturally cooled to room temperature to obtain ZIF-7-derived porous carbon, which is the ZIF-modified material.

[0089] Comparative Example 1

[0090] Mix 2.64 g (12 mmol) of zinc acetate and 2.95 g (36 mmol) of 2-methylimidazole ligand in 120 mL of methanol solvent, and then continuously crystallize in a hydrothermal autoclave at 120 °C for a period of 3 d to obtain crystals. The obtained crystals were washed three times with fresh solvent and then centrifuged to obtain the product, which was dried in an 80 °C oven for 10 h to obtain the ZIF-8 material, that is, the ZIF material.

[0091] Comparative Example 2

[0092] Homogeneous narrow-distribution catalyst calcium acetate.

[0093] Comparative Example 3

[0094] Conventional wide-distribution catalyst KOH.

[0095] The following performance tests were carried out on the ZIF-modified materials obtained in Examples 1 to 3 and the substances in Comparative Examples 1 to 3:

[0096] The above substances were evaluated under the same test conditions. The test conditions were: temperature 180 °C, pressure 0.4 - 0.6 mpa, the reactants were lauryl alcohol (dodecanol) and ethylene oxide, and the dosage of the above substances was 0.1 - 3% of the mass of the substrate (reactants), and the data shown in the following table were obtained.

[0097] Table 2: Performance test data of each substance

[0098]

[0099]

[0100] Among them, EO1 to EO10 in Table 2 are ethoxylates with different ethylene oxide addition numbers, representing the product distribution. From the data in the above table, it can be seen that the substance in Comparative Example 1 is essentially an organic polymer. Although it exhibits certain catalytic activity, it dissolves in the system after the reaction, which will inevitably affect the properties of the product. Therefore, the ZIF-8 material cannot be used as a catalyst. Compared with the catalysts in Comparative Examples 2 to 3, all the catalysts in Examples 1 to 3 have significantly reduced residual alcohols. In terms of product distribution, Examples 1 to 3 are close to Comparative Example 2 and are both better than Comparative Example 3. However, the catalytic activities of the catalysts in Examples 1 to 3 are significantly better than that in Comparative Example 2. The catalyst in Example 1 exhibits significantly better activity than Comparative Examples 2 to 3. Even when the catalyst dosage is reduced to one-thousandth of the substrate, it is still better than Comparative Examples 2 to 3.

[0101] In summary, the ZIF-modified material of the present invention can be used as a catalyst for alkoxylation reactions (alkoxylation reactions of fatty alcohols and epoxides), and has the advantages of higher reaction catalytic activity, lower residual alcohols, and narrower distribution. Moreover, the synthesis method of the ZIF-modified material is simpler and faster.

[0102] For those skilled in the art, it is obvious that the present invention is not limited to the details of the above exemplary embodiments, and can be implemented in other specific forms without departing from the spirit or basic characteristics of the present invention. Therefore, from any point of view, the embodiments should be regarded as exemplary and non-limiting. The scope of the present invention is defined by the appended claims rather than the above description. Therefore, all changes falling within the meaning and scope of the equivalent elements of the claims are intended to be included in the present invention. Any reference signs in the claims should not be regarded as limiting the claimed rights.

[0103] In addition, it should be understood that although this specification is described according to embodiments, not every embodiment only contains an independent technical solution. This narrative way of the specification is only for clarity. Those skilled in the art should regard the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

Claims

1. Application of a ZIF modified material in catalyzing alkoxylation reaction, characterized in that, The ZIF modified material is prepared by calcining the ZIF material.

2. A catalyst for alkoxylation reaction, characterized in that, The catalyst includes the ZIF modified material described in claim 1.

3. A method for preparing a catalyst for alkoxylation reaction as described in claim 2, characterized in that, The preparation method includes the following steps: Perform a calcination treatment on the ZIF material, and then obtain the catalyst.

4. The preparation method of the catalyst for alkoxylation reaction according to claim 3, characterized in that, The step of performing a calcination treatment on the ZIF material includes: Under an inert atmosphere, heat the ZIF material at a heating rate of 5-10 °C / min to 600-800 °C, and then calcine at this temperature for 2.5-3.5 h.

5. The preparation method of the catalyst for alkoxylation reaction according to claim 4, characterized in that, The inert atmosphere includes at least one of a nitrogen atmosphere, a helium atmosphere, and an argon atmosphere.

6. The preparation method of the catalyst for alkoxylation reaction according to claim 3, characterized in that, The ZIF material is subjected to a calcination treatment in a tubular furnace.

7. The preparation method of the catalyst for alkoxylation reaction according to claim 6, characterized in that, The ZIF material is a zeolitic imidazolate framework material.

8. The preparation method of the catalyst for alkoxylation reaction according to claim 7, characterized in that, The preparation steps of the zeolitic imidazolate framework material include: Heat and react a mixed system of a metal salt, an imidazole ligand, and an organic solvent, and obtain a zeolitic imidazolate framework material after the reaction.

9. The preparation method of the catalyst for alkoxylation reaction according to claim 8, characterized in that, The step of obtaining a zeolitic imidazolate framework material after the reaction includes: After washing and drying the solid product obtained from the reaction, obtain the zeolitic imidazolate framework material.

10. The preparation method of the catalyst for alkoxylation reaction according to claim 7, characterized in that, The metal salt includes at least one of a zinc salt and a cobalt salt; The imidazole ligand includes at least one of imidazole, 2-methylimidazole, 2-ethylimidazole, 2-nitroimidazole, 1H-imidazol-1-ylacetonitrile, 4,5-dichloroimidazole, 2-imidazolecarboxaldehyde, 3H-imidazo[4,5-b]pyridine, benzimidazole, 3H-imidazo[4,5-c]pyridine, 7H-imidazo[4,5-d]pyrimidine, 5-chlorobenzimidazole, 5-bromobenzimidazole, and 5-nitrobenzimidazole.

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