Preparation of Cu / ZnO / Al2O3 / ZrO2 composite catalyst and application of Cu / ZnO / Al2O3 / ZrO2 composite catalyst in ethyl phenylacetate hydrogenation

Abstract

The invention relates to preparation of a Cu / ZnO / Al2O3 / ZrO2 composite catalyst and application of the Cu / ZnO / Al2O3 / ZrO2 composite catalyst in hydrogenation of ethyl phenylacetate. According to the catalyst, copper serves as a metal-based active center, non-noble metal is added for modification, the molar ratio of Cu to Zn to Al to Zr is regulated and controlled through a coprecipitation method, the calcination temperature and zirconium source selection are optimized, and the activity, selectivity and stability of the catalyst are remarkably improved. The catalyst shows excellent performance in the hydrogenation reaction of ethyl phenylacetate, and when the molar ratio of Cu < 2 + > to Zn < 2 + > to Al < 3 + > to Zr < 4 + > is 2: 1: 0.1: 0.9 and the calcination temperature is 450 DEG C, the conversion rate of ethyl phenylacetate reaches 84.9%, and the selectivity of the product phenethyl alcohol reaches 90.2%. The introduction of ZrO2 enhances the dispersibility of copper, optimizes the surface acid-base property and mesoporous structure, effectively inhibits side reactions and improves the anti-sintering ability. The preparation method is simple in process, low in cost and suitable for industrial production.

Description

Technical Field

[0001] The present invention belongs to the technical field of catalysts, and specifically relates to the preparation of a Cu / ZnO / Al2O3 / ZrO2 composite catalyst and its application in the hydrogenation of ethyl phenylacetate, specifically the catalyst for the hydrogenation of ethyl phenylacetate. Background Art

[0002] Ester hydrogenation is a key process for producing high-value-added alcohol chemicals. Copper-based catalysts exhibit excellent performance in ester hydrogenation, but traditional copper-based catalysts suffer from issues such as insufficient low-temperature activity, sintering deactivation, and poor selectivity. To further optimize catalyst hydrogenation performance, different preparation methods are being tried to control the dispersion of metal active components, identify the most suitable experimental method for uniquely combining multiple active components, and construct a catalyst system with a synergistic effect through specific preparation processes, which is expected to significantly improve catalyst activity and selectivity. The development of environmentally friendly copper-based catalysts not only reduces energy consumption but is also of great significance for achieving green production of ester-to-alcohol conversion. Summary of the Invention

[0003] To address the shortcomings of the existing technology, the present invention provides a preparation method of a Cu / ZnO / Al2O3 / ZrO2 composite catalyst and its application in the hydrogenation of ethyl phenylacetate. By optimizing the component ratio, calcination temperature, and zirconium source selection, the catalyst is applied in ethyl phenylacetate hydrogenation experiments to maintain good catalytic activity and selectivity while reducing the cost of the hydrogenation catalyst, thereby solving the problems of low activity and poor selectivity of traditional catalysts.

[0004] The present invention provides the following technical solution: In order to achieve the above-mentioned purpose, a Cu / ZnO / Al2O3 / ZrO2 composite catalyst is prepared and its application in the hydrogenation of ethyl phenylacetate is specifically as follows:

[0005] Catalyst preparation: 1.0M Cu(NO₃)₂, 1.0M Zn(NO₃)₂, 1.0M Al(NO₃)₃, 1.0M Zr(NO₃)₄, and a precipitant, 0.5M Na₂CO₃, were prepared. The metal solutions were weighed in the appropriate proportions and poured into a flask, heated to 75°C. At this temperature, 0.5M Na₂CO₃ was added dropwise. Simultaneously, the precipitant was slowly and evenly added to the metal solution using a 250mL dropping funnel at a rate of approximately one drop every two seconds until the pH reached approximately 7.5. The mixture was stirred at 75°C for 2 hours, aged for 1 hour, and the precipitate was filtered and washed to neutrality. The filter cake was vacuum-dried at 100°C for 12 hours and calcined in a muffle furnace at 450°C for 4 hours at a heating rate of 5°C / min. Finally, it was ground and sieved to 80-100 mesh. The prepared catalyst was designated CZAZ.

[0006] The catalyst was used to hydrogenate ethyl phenylacetate. The reaction was carried out in a 1L batch autoclave. 6g of fresh catalyst, 6g of raw material and 400ml of solvent were added and the autoclave was sealed.

[0007] At a certain reaction temperature and pressure, after a period of reaction, the catalyst and the reaction liquid are separated by filtration, and the filtered reaction liquid is subjected to quantitative and qualitative analysis by gas chromatography.

[0008] Preferably, the copper precursor is copper nitrate trihydrate;

[0009] Preferably, the zinc precursor is zinc nitrate hexahydrate;

[0010] Preferably, the aluminum precursor is aluminum nitrate nonahydrate;

[0011] Preferably, the zirconium precursor is zirconium nitrate pentahydrate;

[0012] Preferably, the concentration of the sodium carbonate solution is 0.5 mol / L;

[0013] Preferably, the calcination temperature is 450°C;

[0014] In the present invention, the raw materials used are copper nitrate trihydrate, zinc nitrate hexahydrate, aluminum nitrate nonahydrate and zirconium nitrate pentahydrate, and the preferred component ratio is Cu 2+ :Zn 2+ :Al 3+ :Zr 4+ The molar ratio is 2:1:0.1:0.9, the precipitant is sodium carbonate solution, and the optimal calcination temperature is 450°C. This quaternary catalyst was used in the hydrogenation of ethyl phenylacetate in a batch autoclave under reaction conditions of 180°C, 10 MPa, and 10 hours. The conversion of ethyl phenylacetate and the selectivity for phenylethanol reached 84.9% and 90.2%, respectively, reaching industrial application levels.

[0015] Compared with existing technologies, the present invention has the advantages of using a coprecipitation method to synthesize a Cu-Zn-Al-Zr quaternary catalyst from multiple metal precursors in an alkaline environment, followed by in-situ reduction during the hydrogenation reaction. Existing catalysts are primarily used for CO2 hydrogenation to methanol, but research on ester hydrogenation is insufficient, and the structure-activity relationship is unclear. This catalyst has relatively low preparation costs and good prospects for industrial application. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 This is a flow chart for preparing the catalyst of the present invention;

[0017] Figure 2 The XRD spectra of the Cu / ZnO / Al2O3 / ZrO2 composite catalyst prepared by co-precipitation method at different component ratios of the present invention;

[0018] Figure 3 Isothermal adsorption-desorption curves of the Cu / ZnO / Al2O3 / ZrO2 composite catalyst prepared by co-precipitation method at different component ratios of the present invention;

[0019] Figure 4 The XRD spectra of the Cu / ZnO / Al2O3 / ZrO2 composite catalyst prepared at different temperatures of the present invention;

[0020] Figure 5 Isothermal adsorption-desorption curves of the Cu / ZnO / Al2O3 / ZrO2 composite catalyst prepared at different temperatures of the present invention;

[0021] Figure 6 This is the full XPS spectrum of the Cu / ZnO / Al2O3 / ZrO2 composite catalyst prepared by the co-precipitation method of the present invention;

[0022] Figure 7 This is a gas chromatogram of the Cu / ZnO / Al2O3 / ZrO2 composite catalyst prepared by the co-precipitation method of the present invention after the hydrogenation reaction of ethyl phenylacetate. DETAILED DESCRIPTION

[0023] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0024] Example 1:

[0025] Measure 60 ml of 1M copper nitrate solution, 30 ml of 1M zinc nitrate solution, 27 ml of 1M aluminum nitrate solution, and 3 ml of 1M zirconium nitrate solution, mix thoroughly, and stir at 75°C. Add 0.5 mol / L sodium carbonate solution dropwise until the pH reaches 7.5. Continue stirring for 1 hour. Allow the precipitate to age for 2 hours. Filter, dry for 12 hours, calcine at 450°C for 4 hours, and grind to obtain the CZAZ catalyst.

[0026] Example 2:

[0027] Weigh 60 ml of 1 M copper nitrate solution, 30 ml of 1 M zinc nitrate solution, 21 ml of 1 M aluminum nitrate solution, and 9 ml of 1 M zirconium nitrate solution, mix thoroughly, and stir at 75°C. Add 0.5 mol / L sodium carbonate solution dropwise until the pH reaches 7.5. Continue stirring for 1 hour. Allow the precipitate to age for 2 hours. Filter, dry for 12 hours, calcine at 450°C for 4 hours, and grind to obtain the CZAZ catalyst.

[0028] Example 3:

[0029] Measure 60 ml of 1M copper nitrate solution, 30 ml of 1M zinc nitrate solution, 15 ml of 1M aluminum nitrate solution, and 15 ml of 1M zirconium nitrate solution, mix thoroughly, and stir at 75°C. Add 0.5 mol / L sodium carbonate solution dropwise until the pH reaches 7.5. Continue stirring for 1 hour. Allow the precipitate to age for 2 hours. Filter, dry for 12 hours, calcine at 450°C for 4 hours, and grind to obtain the CZAZ catalyst.

[0030] Example 4:

[0031] Measure 60 ml of 1M copper nitrate solution, 30 ml of 1M zinc nitrate solution, 9 ml of 1M aluminum nitrate solution, and 21 ml of 1M zirconium nitrate solution, mix thoroughly, and stir at 75°C. Add 0.5 mol / L sodium carbonate solution dropwise until the pH reaches 7.5. Continue stirring for 1 hour. Allow the precipitate to age for 2 hours. Filter, dry for 12 hours, calcine at 450°C for 4 hours, and grind to obtain the CZAZ catalyst.

[0032] Example 5:

[0033] Measure 60 ml of 1M copper nitrate solution, 30 ml of 1M zinc nitrate solution, 3 ml of 1M aluminum nitrate solution, and 27 ml of 1M zirconium nitrate solution, mix thoroughly, and stir at 75°C. Add 0.5 mol / L sodium carbonate solution dropwise until the pH reaches 7.5. Continue stirring for 1 hour. Allow the precipitate to age for 2 hours. Filter, dry for 12 hours, calcine at 450°C for 4 hours, and grind to obtain the CZAZ catalyst.

[0034] Example 6:

[0035] Measure 60 ml of 1M copper nitrate solution, 30 ml of 1M zinc nitrate solution, 3 ml of 1M aluminum nitrate solution, and 27 ml of 1M zirconium nitrate solution, mix thoroughly, and stir at 75°C. Add 0.5 mol / L sodium carbonate solution dropwise until the pH reaches 7.5. Continue stirring for 1 hour. Allow the precipitate to age for 2 hours. Filter, dry for 12 hours, calcine at 350°C for 4 hours, and grind to obtain the CZAZ catalyst.

[0036] Example 7:

[0037] Measure 60 ml of 1 M copper nitrate solution, 30 ml of 1 M zinc nitrate solution, 3 ml of 1 M aluminum nitrate solution, and 27 ml of 1 M zirconium nitrate solution, mix thoroughly, and stir at 75°C. Add 0.5 mol / L sodium carbonate solution dropwise until the pH reaches 7.5. Continue stirring for 1 hour. Allow the precipitate to age for 2 hours. Filter, dry for 12 hours, calcine at 550°C for 4 hours, and grind to obtain the CZAZ catalyst.

[0038] Example 8:

[0039] Measure 60 ml of 1M copper nitrate solution, 30 ml of 1M zinc nitrate solution, 3 ml of 1M aluminum nitrate solution, and 27 ml of 1M zirconium nitrate solution, mix thoroughly, and stir at 75°C. Add 0.5 mol / L sodium carbonate solution dropwise until the pH reaches 7.5. Continue stirring for 1 hour. Allow the precipitate to age for 2 hours. Filter, dry for 12 hours, calcine at 650°C for 4 hours, and grind to obtain the CZAZ catalyst.

[0040] Table 1 Effect of different catalysts on catalytic hydrogenation of ethyl phenylacetate

[0041]

[0042] As shown in Table 1, the Cu / ZnO / Al2O3 / ZrO2 catalyst prepared by the coprecipitation method can be prepared under relatively mild conditions. When used in the selective hydrogenation of ethyl phenylacetate to phenylethanol, the catalyst achieves a maximum ethyl phenylacetate conversion of 84.9% and a phenylethanol selectivity of 90.2% at a specific temperature and pressure, demonstrating excellent reaction performance. The catalyst prepared by the present invention can meet the needs of industrial production.

[0043] While embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions, and variations may be made to these embodiments without departing from the principles and spirit of the invention, and that the scope of the invention is defined by the appended claims and their equivalents.

Claims

1. Preparation of a Cu / ZnO / Al2O3 / ZrO2 composite catalyst and its application in the hydrogenation of ethyl phenylacetate, characterized in that: The catalyst uses copper as the active center and is modified by adding multiple non-precious metals. The molar ratio of Cu, Zn, Al, and Zr is regulated by a coprecipitation method, and the reaction pH is controlled to obtain a uniformly dispersed nanocatalyst. Ethyl phenylacetate is dissolved in a methanol solution, and pressure H2 is injected at room temperature to perform a catalytic hydrogenation reaction to obtain phenylethanol. The preparation method of the catalyst and the catalytic hydrogenation reaction conditions are specifically as follows: 1) Preparation of catalyst: 1.0M Cu(NO3)2, 1.0M Zn(NO3)2, 1.0M Al(NO3)3, 1.0M Zr(NO3)4 and 0.5M Na2CO3 as precipitant were prepared respectively, the metal solutions were weighed and poured into a flask according to a certain proportion and heated to 75°C, 0.5M Na2CO3 was added dropwise at this temperature, and the precipitant was slowly and uniformly added dropwise to the metal solution using a 250mL dropping funnel, with the drop rate controlled at about one drop every two seconds until the pH reached about 7.5, and the mixture was stirred continuously at 75°C for 2h, aged for 1h, and the precipitate was filtered and washed to neutrality. The filter cake was vacuum dried at 100°C for 12h, and calcined at 450°C in a muffle furnace at a heating rate of 5°C / min for 4h; finally, the mixture was ground and sieved to 80-100 mesh. The prepared catalyst was named CZAZ; 2) Hydrogenation of ethyl phenylacetate with catalyst: The reaction was carried out in a 1 L batch autoclave. 6 g of fresh catalyst, 6 g of ethyl phenylacetate, and 400 ml of solvent were added, and the autoclave was sealed. Before the reaction, 3 MPa of H₂ was passed into the autoclave to check for airtightness. If the airtightness was good, the autoclave was replaced with hydrogen three times to remove air. After a period of reaction at a certain reaction temperature and pressure, the catalyst and reaction liquid were separated by filtration, and the filtered reaction liquid was subjected to quantitative and qualitative analysis by gas chromatography.

2. The preparation of a Cu / ZnO / Al2O3 / ZrO2 composite catalyst according to claim 1 and its application in the hydrogenation of ethyl phenylacetate, characterized in that: The concentration of the precipitant sodium carbonate solution is 0.5 mol / L.

3. The preparation of a Cu / ZnO / Al2O3 / ZrO2 composite catalyst according to claim 1 and its application in the hydrogenation of ethyl phenylacetate, characterized in that: The pH of the precipitation is controlled at 7.5-8.

4. The preparation of a Cu / ZnO / Al2O3 / ZrO2 composite catalyst according to claim 1 and its application in the hydrogenation of ethyl phenylacetate, characterized in that: The molar ratio of Cu2+:Zn2+:Al3+:Zr4+ is 2:1:0.1:0.

9.

5. The preparation of a Cu / ZnO / Al2O3 / ZrO2 composite catalyst according to claim 1 and its application in the hydrogenation of ethyl phenylacetate, characterized in that: The calcination temperature was controlled at 450°C and the heating rate was 5°C / min.

6. The preparation of a Cu / ZnO / Al2O3 / ZrO2 composite catalyst and its application in the hydrogenation of ethyl phenylacetate according to claim 1, characterized in that: The catalytic hydrogenation reaction uses a batch reactor.

7. The preparation of a Cu / ZnO / Al2O3 / ZrO2 composite catalyst and its application in the hydrogenation of ethyl phenylacetate according to claim 1, characterized in that: The reaction temperature of the catalytic hydrogenation reaction is 180° C. and the pressure is 10 MPa.

8. The preparation of a Cu / ZnO / Al2O3 / ZrO2 composite catalyst and its application in the hydrogenation of ethyl phenylacetate according to claim 1, characterized in that: The solvent used in the catalytic hydrogenation reaction is methanol.

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