Preparation method and application of an oxime ether functionalized modified UiO-66-OH catalyst retaining acetate in situ
By functionalizing the UiO-66-OH catalyst with in-situ retained acetate and oxime ether, the problem of insufficient catalytic activity was solved, and efficient catalytic oxidation of 1,2-propanediol to hydroxyacetone was achieved with high yield and good stability.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- ZHENGZHOU UNIV
- Filing Date
- 2026-04-27
- Publication Date
- 2026-06-19
AI Technical Summary
Existing metal-organic framework catalysts exhibit insufficient catalytic activity in the oxidation of 1,2-propanediol to hydroxyacetone, and their organic ligand regulation is limited, making it difficult to achieve rich active sites, tunable node coordination environment, synergistic acid-base regulation, and high stability.
By in-situ retaining acetate and introducing oxime ether functionalization to modify the UiO-66-OH catalyst, a catalytic system with abundant active sites and tunable acid-base properties was constructed, enhancing the interaction between the catalyst and the substrate. The modified catalyst was synthesized using specific steps.
The catalyst exhibits high activity and stability, with a hydroxyacetone yield exceeding 45%, and demonstrates excellent reusability.
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Figure CN122234403A_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of catalyst preparation technology, specifically relating to a method for preparing and applying an in-situ oxime ether functionalized modified UiO-66-OH catalyst with retained acetate ions. Background Technology
[0002] Hydroxyacetone is an important high-value chemical widely used in food, cosmetics, and pharmaceuticals, with broad application prospects. The selective oxidation of 1,2-propanediol, which is readily available and has low toxicity, to prepare hydroxyacetone via liquid-phase oxidation is considered a green synthetic route with great application potential. Currently, the catalysts used in the oxidation of 1,2-propanediol to hydroxyacetone mainly include noble metal catalysts and metal-organic framework catalysts. While noble metal catalysts generally possess certain activity, they commonly suffer from high preparation costs, easy loss of metal components, difficulties in separation and recovery, and insufficient cycle stability, thus limiting their further application. In contrast, metal-organic framework catalysts have advantages such as large specific surface area, highly tunable pore structure, and easy control of composition and function, showing better application potential in the oxidation of 1,2-propanediol to hydroxyacetone.
[0003] Metal-organic framework catalysts, represented by UiO-66, have attracted widespread attention due to their high thermal and chemical stability. Previous research (V. Torbina et al, Effect of organic linker substituent on catalytic activity of UiO-66 metal-organic framework in selective oxidation of propylene glycol: homolytic versus heterolytic activation of hydrogenperoxide, Materials Today Chemistry. 2022, 24, 100776) has shown that UiO-66-X catalysts modified with different organic ligands (–NH2, –NO2, –OH, etc.) exhibit significantly different catalytic performance in the liquid-phase oxidation of 1,2-propanediol to hydroxyacetone. Among them, UiO-66-NO2 showed a higher hydroxyacetone yield of 15.58%, while UiO-66-OH showed a relatively lower catalytic yield of 4.25%. This indicates that the regulation of organic ligands has an important impact on catalytic performance. It also shows that relying solely on a single functional group to construct the active site still has certain limitations in regulating catalyst properties and thus improving the catalytic performance of the catalyst for the production of hydroxyacetone from 1,2-propanediol. It is worth noting that research (Arup Tarai et al., A review on oxime functionality: an ordinary functional group with significant impacts in supramolecular chemistry, Chemical Science) has shown that... . 2024, 38); (Cheng Xiaoding, Application of Oxime Ethers as Directing Groups in Palladium-Catalyzed CH Activation, Modern Chemical Industry, 2019, 48). Oxime ether functional groups can be used as directing groups, inducing C–H bond activation through coordination with the metal center, thereby significantly regulating the reaction pathway and conversion efficiency of the substrate in the catalytic process. Therefore, introducing oxime ether groups into metal-organic framework materials is expected to provide new structural design ideas for improving catalyst activity by regulating the interaction between the catalyst and the substrate.
[0004] Furthermore, an effective modification strategy for UiO-66 type catalysts utilizes carboxylic acids such as acetic acid as modifiers. This type of method typically focuses on exposing as many coordinated unsaturated metal sites as possible through subsequent solvent exchange to enhance catalytic activity. Monocarboxylic acids, after competing for coordination with organic ligands during synthesis, are washed away as much as possible and are not retained as nodal coordination components. However, the role of acetate ions in participating in nodal coordination during catalyst formation and regulating the local coordination environment at nodes to enhance catalytic activity has not yet been fully considered and utilized as a functional building block.
[0005] To address the aforementioned issues, there is an urgent need to develop a catalyst that is rich in active sites, has an tunable nodal coordination environment, can synergistically regulate the acidity and basicity of the catalyst and enhance its interaction with the substrate, and simultaneously possesses high stability and high catalytic activity, in order to improve the catalytic performance of the liquid-phase oxidation of 1,2-propanediol to hydroxyacetone. Summary of the Invention
[0006] To address the aforementioned problems, this invention provides an in-situ oxime ether functionalized modified UiO-66-OH catalyst with retained acetate ions, its preparation method, and its applications. This catalyst, through synergistic regulation of the organic ligands and nodal coordination environment, constructs a catalytic system rich in active sites and tunable in acid-base properties, enhancing the interaction between the catalyst and the 1,2-propanediol substrate and improving the catalytic activity of the liquid-phase oxidation of 1,2-propanediol to hydroxyacetone. Simultaneously, this catalyst also exhibits a high yield of hydroxyacetone, as well as good structural stability and recyclability.
[0007] To achieve the above objectives, the technical solution of the present invention is as follows: In a first aspect, a method for preparing an in-situ acetate-retaining oxime ether-functionalized modified UiO-66-OH catalyst is provided, comprising the following steps: S1: Zirconium acetate and 2-hydroxyterephthalic acid ligand are dissolved in N,N-dimethylformamide to form a mixed solution; the mixed solution is transferred to a microwave reactor for reaction; after the reaction is completed, the solution is centrifuged, washed, and dried to obtain UiO-66-OH-(OAc)x; S2: Disperse the above-obtained UiO-66-OH-(OAc)x in N,N-dimethylformamide, add cesium carbonate, and after ultrasonic dispersion, add 2-bromoacetal diethyl acetal under nitrogen protection, mix evenly, and transfer to a hydrothermal reactor for reaction. After the reaction is completed, centrifuge, wash, and dry to obtain UiO-66-AP-(OAc)x. S3: Disperse the above-obtained UiO-66-AP-(OAc)x in a mixed solution of 1,4-dioxane and 10wt% dilute hydrochloric acid. After mixing evenly, reflux and heat to react. After the reaction is completed, centrifuge, wash and dry to obtain UiO-66-CHO-(OAc)x. S4: Disperse the above-obtained UiO-66-CHO-(OAc)x in anhydrous ethanol, add benzyl hydroxylamine hydrochloride and anhydrous sodium acetate to obtain a mixed solution, mix evenly and transfer to a microwave reactor for reaction. After the reaction is completed, centrifuge, wash and dry to obtain UiO-66-OE-(OAc)x, that is, UiO-66-OH catalyst with in-situ retained acetate oxime ether functionalization modification.
[0008] Preferably, in step S1, the amount of zirconium acetate in each milliliter of N,N-dimethylformamide is 0.03-0.08 g, the amount of 2-hydroxyterephthalic acid in each milliliter of N,N-dimethylformamide is 0.04-0.16 g, and the microwave reaction is carried out at 100-140℃ for 10-18 h.
[0009] Preferably, in step S2, the mass ratio of UiO-66-OH-(OAc)x, N,N-dimethylformamide, cesium carbonate and 2-bromoacetal diethyl acetal is 2:30-50:1-5:1-5, and the hydrothermal reaction is carried out at 120-140℃ for 8-10 hours.
[0010] Preferably, in step S3, the mass ratio of UiO-66-AP-(OAc)x to 1,4-dioxane and 10wt% dilute hydrochloric acid is 1.5:10-30:1-5, the reflux heating temperature is 100-120℃, and the heating time is 8-12h.
[0011] Preferably, in step S4, the mass ratio of UiO-66-CHO-(OAc)x to anhydrous ethanol, benzyl hydroxylamine hydrochloride, and anhydrous sodium acetate is 1:10-50:1-5:1-10, and the microwave reaction is carried out at 80-100℃ for 10-12 hours.
[0012] In a second aspect, the present invention provides a modified UiO-66-OH catalyst prepared by the preparation method described in the first aspect of the present invention.
[0013] Preferably, the specific surface area of the modified UiO-66-OH synthesized in step S4 is not less than 1000 m². 2 / g.
[0014] In a third aspect, the present invention provides the application of the modified UiO-66-OH catalyst prepared by the preparation method described in the first aspect in the catalytic liquid-phase oxidation of 1,2-propanediol to hydroxyacetone.
[0015] Preferably, the mass ratio of the modified UiO-66-OH, 1,2-propanediol, 30% hydrogen peroxide, and N,N-dimethylformamide in step S4 is 1:1-5:1-5:10-30, the reaction temperature is 20-40℃, and the reaction time is 1-3h. The catalytic test is performed, and the results are analyzed by gas chromatography. The yield of hydroxyacetone is over 45%.
[0016] Compared with the prior art, the beneficial effects of the present invention are: 1. The modified UiO-66-OH catalyst provided by this invention achieves synergistic regulation of the nodal coordination environment and organic ligand functionalization by retaining acetate ions in situ and introducing oxime ether functional groups, thus constructing a richer active site system. The retention of acetate ions in the Zr cluster nodes can participate in the construction of the local coordination environment at the nodes, while the oxime ether functionalization structure helps to enhance the catalyst's adsorption and activation ability for substrates. The two work synergistically to optimize and regulate the acid-base properties of the catalyst and the interaction behavior with the substrate.
[0017] 2. The modified UiO-66-OH catalyst provided by this invention possesses strong structural stability and catalytic activity, and exhibits good recyclability. This catalyst demonstrates high catalytic activity and target product yield in the liquid-phase oxidation of 1,2-propanediol to hydroxyacetone, with the hydroxyacetone yield reaching over 45%. Attached Figure Description
[0018] To more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings used in the description of the embodiments of the present invention or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.
[0019] Figure 1 The ¹H NMR spectrum of the modified UiO-66-OH catalyst prepared in Example 1; Figure 2 A scanning electron microscope image of the modified UiO-66-OH catalyst prepared in Example 1; Figure 3 NH3-TPD diagrams of the modified UiO-66-OH catalyst prepared in Example 1 and the UiO-66-OH catalyst prepared in Comparative Example 1; Figure 4 X-ray diffraction patterns of the modified UiO-66-OH catalysts prepared in Examples 1-3 and the UiO-66-OH catalyst prepared in Comparative Example 1; Figure 5The yield curves of the catalysts prepared in Examples 1-3 and Comparative Examples 1-3 were obtained in the liquid-phase oxidation of 1,2-propanediol to hydroxyacetone. Figure 6 The modified UiO-66-OH catalyst prepared in Example 1 was used in the liquid-phase oxidation of 1,2-propanediol to hydroxyacetone experiment. The hydroxyacetone yield curve was obtained by repeating the performance test five times. In the figure, 1-5 represent the number of repetitions. Detailed Implementation
[0020] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention. Example
[0021] S1: Dissolve 0.074 g / mL zirconium acetate and 2.06 g 2-hydroxyterephthalic acid ligand in 50 mL N,N-dimethylformamide to form a mixed solution; transfer the mixed solution to a microwave reactor at 120 °C and react for 15 h. After the reaction is completed, centrifuge, wash and dry to obtain UiO-66-OH-(OAc)x; S2: Disperse the above-obtained 2g UiO-66-OH-(OAc)x in 50mL N,N-dimethylformamide, add 1g cesium carbonate, and after ultrasonic dispersion, add 2mL 2-bromoacetal diethyl acetal under nitrogen protection. After mixing evenly, transfer to a hydrothermal reactor at 130℃ and react for 10h. After the reaction is completed, centrifuge, wash, and dry to obtain UiO-66-AP-(OAc)x; S3: Disperse the 1.5g UiO-66-AP-(OAc)x obtained above in 20mL of a mixed solution of 1,4-dioxane and 1mL of 10wt% dilute hydrochloric acid. After mixing evenly, reflux at 110℃ for 10h. After the reaction is completed, centrifuge, wash, and dry to obtain UiO-66-CHO-(OAc)x. S4: Disperse 1g of the obtained UiO-66-CHO-(OAc)x in 40mL of anhydrous ethanol, add a mixed solution of 3g benzyl hydroxylamine hydrochloride and 5g anhydrous sodium acetate, mix well, and transfer to a microwave reactor at 90℃ for 12h. After the reaction is completed, centrifuge, wash and dry to obtain UiO-66-OE-(OAc)x, which is the in-situ oxime ether functionalized modified UiO-66-OH catalyst with acetate ion retained.
[0022] Figure 1The ¹H NMR spectrum of the modified UiO-66-OH catalyst prepared in Example 1 shows the presence of signals characteristic of acetate and oxime ether groups, indicating the presence of these two chemical structural units in the catalyst.
[0023] Figure 2 The image shows a scanning electron microscope (SEM) image of the modified UiO-66-OH catalyst prepared in Example 1; it can be seen that the catalyst particles have a polyhedral configuration. Example
[0024] S1: Dissolve 0.074 g / mL zirconium acetate and 7.37 g 2-hydroxyterephthalic acid ligand in 50 mL N,N-dimethylformamide to form a mixed solution; transfer the mixed solution to a microwave reactor at 120 °C and react for 15 h. After the reaction is completed, centrifuge, wash and dry to obtain UiO-66-OH-(OAc)x; S2: Disperse the above-obtained 2g UiO-66-OH-(OAc)x in 50mL N,N-dimethylformamide, add 1g cesium carbonate, and after ultrasonic dispersion, add 2mL 2-bromoacetal diethyl acetal under nitrogen protection. After mixing evenly, transfer to a hydrothermal reactor at 130℃ and react for 10h. After the reaction is completed, centrifuge, wash, and dry to obtain UiO-66-AP-(OAc)x; S3: Disperse the 1.5g UiO-66-AP-(OAc)x obtained above in 20mL of a mixed solution of 1,4-dioxane and 1mL of 10wt% dilute hydrochloric acid. After mixing evenly, reflux at 110℃ for 10h. After the reaction is completed, centrifuge, wash, and dry to obtain UiO-66-CHO-(OAc)x. S4: Disperse 1g of the obtained UiO-66-CHO-(OAc)x in 40mL of anhydrous ethanol, add a mixed solution of 3g benzyl hydroxylamine hydrochloride and 5g anhydrous sodium acetate, mix well, and transfer to a microwave reactor at 90℃ for 12h. After the reaction is completed, centrifuge, wash and dry to obtain UiO-66-OE-(OAc)x, which is the in-situ oxime ether functionalized modified UiO-66-OH catalyst with acetate ion retained. Example
[0025] S1: Dissolve 0.074 g / mL zirconium acetate and 2.06 g 2-hydroxyterephthalic acid ligand in 50 mL N,N-dimethylformamide to form a mixed solution; transfer the mixed solution to a microwave reactor at 120 °C and react for 15 h. After the reaction is completed, centrifuge, wash and dry to obtain UiO-66-OH-(OAc)x; S2: Disperse the above-obtained 2g UiO-66-OH-(OAc)x in 50mL N,N-dimethylformamide, add 1g cesium carbonate, and after ultrasonic dispersion, add 2mL 2-bromoacetal diethyl acetal under nitrogen protection. After mixing evenly, transfer to a hydrothermal reactor at 130℃ and react for 10h. After the reaction is completed, centrifuge, wash, and dry to obtain UiO-66-AP-(OAc)x; S3: Disperse the 1.5g UiO-66-AP-(OAc)x obtained above in 20mL of a mixed solution of 1,4-dioxane and 1mL of 10wt% dilute hydrochloric acid. After mixing evenly, reflux at 110℃ for 10h. After the reaction is completed, centrifuge, wash, and dry to obtain UiO-66-CHO-(OAc)x. S4: Disperse 1g of the obtained UiO-66-CHO-(OAc)x in 40mL of anhydrous ethanol, add 5g of benzyl hydroxylamine hydrochloride and 10g of anhydrous sodium acetate, mix well and transfer to a microwave reactor at 90℃ for 12h. After the reaction is completed, centrifuge, wash and dry to obtain UiO-66-OE-(OAc)x, that is, UiO-66-OH catalyst with in-situ retained acetate oxime ether functionalization modification.
[0026] Comparative Example 1 The preparation method of Comparative Example 1 differs from that of Example 1 in that the zirconium source of Comparative Example 1 is zirconium tetrachloride, there is no in-situ retention of acetate, and no oxime ether functionalization is performed.
[0027] S1: Dissolve 2.64 g of zirconium tetrachloride and 2.06 g of 2-hydroxyterephthalic acid ligand in 50 mL of N,N-dimethylformamide to form a mixed solution; transfer the mixed solution to a microwave reactor at 120 °C and react for 15 h. After the reaction is completed, centrifuge, wash and dry to obtain UiO-66-OH.
[0028] Comparative Example 2 The preparation method of Comparative Example 2 is the same as that of Example 1, except that Comparative Example 2 does not undergo oxime ether functionalization.
[0029] S1: Dissolve 0.074 g / mL zirconium acetate and 2.06 g 2-hydroxyterephthalic acid ligand in 50 mL N,N-dimethylformamide to form a mixed solution; transfer the mixed solution to a microwave reactor at 120 °C and react for 15 h. After the reaction is completed, centrifuge, wash and dry to obtain UiO-66-OH-(OAc)x.
[0030] Comparative Example 3 The preparation method of Comparative Example 3 is basically the same as that of Example 1, except that the zirconium source of Comparative Example 3 is zirconium tetrachloride, and there is no in-situ retained acetate.
[0031] S1: Dissolve 2.64 g of zirconium tetrachloride and 2.06 g of 2-hydroxyterephthalic acid ligand in 50 mL of N,N-dimethylformamide to form a mixed solution; transfer the mixed solution to a microwave reactor at 120 °C and react for 15 h. After the reaction is completed, centrifuge, wash and dry to obtain UiO-66-OH. S2: Disperse the above-obtained 2g UiO-66-OH in 50mL N,N-dimethylformamide, add 1g cesium carbonate, and after ultrasonic dispersion, add 2mL 2-bromoacetal diethyl acetal under nitrogen protection, mix evenly, and transfer to a hydrothermal reactor at 130℃ for 10h. After the reaction is completed, centrifuge, wash, and dry to obtain UiO-66-AP; S3: Disperse the 1.5g UiO-66-AP obtained above in 20mL of a mixed solution of 1,4-dioxane and 1mL of 10wt% dilute hydrochloric acid. After mixing evenly, reflux at 110℃ for 10h. After the reaction is completed, centrifuge, wash, and dry to obtain UiO-66-CHO. S4: Disperse 1g of the obtained UiO-66-CHO in 40mL of anhydrous ethanol, add a mixed solution of 3g benzyl hydroxylamine hydrochloride and 5g anhydrous sodium acetate, mix well, and then transfer to a microwave reactor at 90℃ for 12h. After the reaction is completed, centrifuge, wash and dry to obtain the UiO-66-OE catalyst.
[0032] The catalysts prepared in Examples 1-3 and Comparative Examples 1-3 were reacted with 1,2-propanediol, 30% hydrogen peroxide, and N,N-dimethylformamide in a mass ratio of 1:1-5:1-5:10-30 at a reaction temperature of 20-40°C for 1-3 hours. Catalytic effects were tested using gas chromatography. Figure 5 As shown.
[0033] Figure 3 The NH3-TPD diagrams are of the modified UiO-66-OH catalyst prepared in Example 1 and the UiO-66-OH catalyst prepared in Comparative Example 1. It can be seen that, compared with Comparative Example 1, the TPD signal of Example 1 shifts towards higher temperatures, indicating that its surface acid strength is enhanced.
[0034] Figure 4 The X-ray diffraction patterns are those of the modified UiO-66-OH catalysts prepared in Examples 1-3 and the UiO-66-OH catalyst prepared in Comparative Example 1. It can be seen that the modified UiO-66-OH catalysts prepared in Examples 1-3 retain the typical UiO-66-OH characteristic peaks of the UiO-66-OH catalyst in Comparative Example 1, indicating that they maintain a good framework structure.
[0035] Figure 5The graphs show the hydroxyacetone yield curves obtained by the catalysts prepared in Examples 1-3 and Comparative Examples 1-3 in the liquid-phase oxidation of 1,2-propanediol to hydroxyacetone. It can be seen that the UiO-66-OH catalyst modified with oxime ether functionalized ligands and retaining acetate in situ has a higher yield, with the hydroxyacetone yield reaching more than 45%, which has high application value.
[0036] Figure 6 The modified UiO-66-OH catalyst prepared in Example 1 was subjected to five repeated performance tests in the liquid-phase oxidation of 1,2-propanediol to hydroxyacetone, resulting in a hydroxyacetone yield curve. In the figure, 1-5 represent the number of repetitions. It can be seen that the yield of the modified UiO-66-OH catalyst in the liquid-phase oxidation of 1,2-propanediol to hydroxyacetone did not decrease significantly after five consecutive cycles, indicating that the modified UiO-66-OH catalyst prepared in Example 1 has good recyclability.
[0037] The pore structure of the modified UiO-66-OH catalysts prepared in Examples 1-3 was analyzed using a Kanta Autosorb IQ2 instrument. The test results are shown in Table 1.
[0038]
[0039] Table 1 shows the pore structure parameters of the modified UiO-66-OH catalysts prepared in Examples 1-3; it can be seen that their specific surface areas are all above 1000 m². 2 / g or more.
Claims
1. A method for preparing an in-situ acetate-retaining oxime ether functionalized modified UiO-66-OH catalyst, characterized in that, Includes the following steps: S1: Zirconium acetate and 2-hydroxyterephthalic acid ligand are dissolved in N,N-dimethylformamide to form a mixed solution; the mixed solution is transferred to a microwave reactor for reaction; after the reaction is completed, the solution is centrifuged, washed, and dried to obtain UiO-66-OH-(OAc)x; S2: Disperse the above-obtained UiO-66-OH-(OAc)x in N,N-dimethylformamide, add cesium carbonate, and after ultrasonic dispersion, add 2-bromoacetal diethyl acetal under nitrogen protection, mix evenly, and transfer to a hydrothermal reactor for reaction. After the reaction is completed, centrifuge, wash, and dry to obtain UiO-66-AP-(OAc)x. S3: Disperse the above-obtained UiO-66-AP-(OAc)x in a mixed solution of 1,4-dioxane and 10wt% dilute hydrochloric acid. After mixing evenly, reflux and heat to react. After the reaction is completed, centrifuge, wash and dry to obtain UiO-66-CHO-(OAc)x. S4: The obtained UiO-66-CHO-(OAc)x was dispersed in anhydrous ethanol, and benzyl hydroxylamine hydrochloride and anhydrous sodium acetate were added to obtain a mixed solution. After mixing evenly, the solution was transferred to a microwave reactor for reaction. After the reaction was completed, the solution was centrifuged, washed, and dried to obtain UiO-66-OE-(OAc)x, which is an in-situ oxime ether functionalized modified UiO-66-OH catalyst with acetate ion retained; its specific surface area is not less than 1000 m². 2 / g.
2. The preparation method of the in-situ acetate-retaining oxime ether functionalized modified UiO-66-OH catalyst according to claim 1, characterized in that, In step S1, the amount of zirconium acetate used per milliliter of N,N-dimethylformamide is 0.03-0.08 g, and the amount of 2-hydroxyterephthalic acid used per milliliter of N,N-dimethylformamide is 0.04-0.16 g.
3. The method for preparing an in-situ acetate-retaining oxime ether functionalized modified UiO-66-OH catalyst according to claim 1, characterized in that, In step S1, the reaction temperature of the microwave reactor is 100-140℃ and the reaction time is 10-18h.
4. The preparation method of the in-situ acetate-retaining oxime ether functionalized modified UiO-66-OH catalyst according to claim 1, characterized in that, In step S2, the mass ratio of UiO-66-OH-(OAc)x, N,N-dimethylformamide, cesium carbonate and 2-bromoacetal diethyl acetal is 2:30-50:1-5:1-5.
5. The method for preparing an in-situ acetate-retaining oxime ether functionalized modified UiO-66-OH catalyst according to claim 1, characterized in that, In step S2, the hydrothermal reaction temperature in the hydrothermal reactor is 120-140℃ and the reaction time is 8-10h.
6. The method for preparing an in-situ acetate-retaining oxime ether functionalized modified UiO-66-OH catalyst according to claim 1, characterized in that, In step S3, the mass ratio of UiO-66-AP-(OAc)x, 1,4-dioxane, and 10wt% dilute hydrochloric acid is 1.5:10-30:1-5.
7. The method for preparing an in-situ acetate-retaining oxime ether functionalized modified UiO-66-OH catalyst according to claim 1, characterized in that, In step S3, the reflux heating reaction temperature is 100-120℃ and the reaction time is 8-12h.
8. The method for preparing an in-situ acetate-retaining oxime ether functionalized modified UiO-66-OH catalyst according to claim 1, characterized in that, In step S4, the mass ratio of UiO-66-CHO-(OAc)x, anhydrous ethanol, benzyl hydroxylamine hydrochloride and anhydrous sodium acetate is 1:10-50:1-5:1-10.
9. The method for preparing an in-situ acetate-retaining oxime ether functionalized modified UiO-66-OH catalyst according to claim 1, characterized in that, In step S4, the microwave reactor is reacted at a temperature of 80-100℃ for 10-12 hours.
10. The application of the catalyst prepared by the method for preparing the in-situ acetate-retaining oxime ether functionalized modified UiO-66-OH catalyst according to any one of claims 1-9 in the catalytic liquid-phase oxidation of 1,2-propanediol to hydroxyacetone.
11. The application according to claim 10, characterized in that, The modified UiO-66-OH catalyst, 1,2-propanediol, 30% hydrogen peroxide, and N,N-dimethylformamide were added to the reaction vessel at a mass ratio of 1:1-5:1-5:10-30 to carry out the catalytic reaction. The reaction temperature was 20-40℃ and the reaction time was 1-3h. The results of gas chromatography analysis showed that the yield of hydroxyacetone was over 45%.