Catalyst for synthesizing acrylic acid from acetylene as well as preparation method and application of catalyst

Abstract

The invention relates to a catalyst for synthesizing acrylic acid from acetylene as well as a preparation method and application of the catalyst. A preparation method of a catalyst for synthesizing acrylic acid from acetylene comprises the following steps: (1) completely dissolving a copper salt, a zinc salt and an aluminum salt in water, adding a precipitant, and stirring to react for 0.5-2 hours to obtain slurry; (2) filtering the slurry, collecting solids, washing, grinding and drying to obtain a catalyst precursor Cu-LDH; and (3) calcining the catalyst precursor Cu-LDH at 300-500 DEG C for 3-6 hours to obtain the catalyst for synthesizing acrylic acid from acetylene. According to the catalyst for synthesizing acrylic acid from acetylene and the preparation method and application of the catalyst, the preparation method is simple and low in cost, and the synthesized catalyst is good in stability and has recyclability.

Description

Technical Field

[0001] The present invention belongs to the technical field of catalysts, and in particular relates to a catalyst for synthesizing acrylic acid from acetylene, and a preparation method and application thereof. Background Art

[0002] The production of calcium carbide (CaC2) in an industrial setting typically involves reacting coal and calcium oxide in an electric furnace. In recent years, CaC2 has become an important organic raw material for the production of acetylene. The use of CaC2 is an attractive approach, providing a new approach to producing acetylene from non-petroleum resources. Reusing the byproduct CO in CaC2 production also makes the process applicable to various green chemistry strategies.

[0003] The Reppe reaction of acetylene with CO or hydrogen-containing compounds (such as water) is the most important process in the production of carboxylic acid monomers. Carbonylation products, such as acrylic acid (AA) and its derivatives, are widely used in the production of polymers, including plastics, synthetic rubber and fibers. Therefore, the use of waste gas will allow CO to be utilized as a benign C1 raw material to produce more sustainable compounds (AA). This strategy not only meets the world's demand for sustainable development, but is also a very promising process line for the production of acrylic acid, which can not only alleviate the severe supply and demand contradiction of acrylic acid, but also greatly reduce the cost of producing acrylic acid and the dependence on petroleum.

[0004] The carbonylation of C₂H₂ and CO to produce acrylic acid requires a catalyst. In the prior art method for carbonylating acetylene to produce methyl acrylate, disclosed in CN105753700A, a palladium-based catalyst immobilized on an organic ligand polymer is used to catalyze the carbonylation of acetylene to produce methyl acrylate. However, this method utilizes an organic reaction system for catalyst preparation, resulting in complex preparation, high cost, and environmental concerns. This hinders the carbonylation of acetylene to produce methyl acrylate.

[0005] In view of this, the present invention provides a novel catalyst for synthesizing acrylic acid from acetylene, and its preparation method and application. The synthesized heterogeneous copper-based catalyst has a simple preparation method and good catalytic performance. Summary of the Invention

[0006] The object of the present invention is to provide a method for preparing a catalyst for synthesizing acrylic acid from acetylene. The method is simple and the raw materials are cheap and readily available.

[0007] In order to achieve the above objectives, the technical solutions adopted are:

[0008] A method for preparing a catalyst for synthesizing acrylic acid from acetylene comprises the following steps:

[0009] (1) After completely dissolving the copper salt, zinc salt, and aluminum salt in water, add a precipitant and stir the reaction for 0.5-2 hours to obtain a slurry;

[0010] (2) filtering the slurry, collecting the solid, washing, drying, and grinding to obtain the catalyst precursor Cu-LDH;

[0011] (3) calcining the catalyst precursor Cu-LDH at 300-500° C. for 3-6 hours to obtain the catalyst for synthesizing acrylic acid from acetylene.

[0012] Furthermore, the molar ratio of the copper salt, zinc salt and aluminum salt is 0.5-2:1:1.

[0013] Furthermore, in the step (1), the copper salt is Cu(NO3)2, the zinc salt is Zn(NO3)2, and the aluminum salt is Al(NO3)3;

[0014] The precipitant is 0.5-1 mol / L sodium carbonate solution.

[0015] Furthermore, in the step (1), NaOH solution is used to adjust the pH value of the reaction system to 8-11.

[0016] Furthermore, in the step (1), the pH value of the reaction system is 10-11.

[0017] Furthermore, in the step (3), the calcination atmosphere is air, hydrogen, or nitrogen.

[0018] Furthermore, in the step (3), the calcination atmosphere is nitrogen.

[0019] Another object of the present invention is to provide a catalyst for synthesizing acrylic acid from acetylene, which is prepared using the above-mentioned preparation method.

[0020] Another object of the present invention is to provide the use of the catalyst for synthesizing acrylic acid from acetylene in catalyzing the carbonylation of C2H2 and CO to synthesize acrylic acid.

[0021] Compared with the prior art, the present invention has the following beneficial effects:

[0022] 1. The technical solution of the present invention synthesizes a layered double hydroxide (LDH) precursor by a precipitation method. The precursor is heated under different atmospheres (air, hydrogen and nitrogen) and the conditions of the calcination gas are changed to achieve the purpose of changing the valence state of copper and the dispersion of copper. The prepared catalyst can achieve a selectivity of more than 80% for acrylic acid in the acetylene carbonylation reaction.

[0023] 2. The technical solution of the present invention utilizes soluble copper salts, zinc salts, and aluminum salts to prepare the catalyst. The raw materials are cheap and readily available, the preparation method is simple, and it is easy to industrialize. At the same time, the heterogeneous copper-based catalyst prepared by the present invention exhibits good activity in the acetylene carbonylation reaction, has a high yield of acrylic acid, and is recyclable. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 These are the XRD patterns of the catalyst precursor Cu-LDH prepared at different pH values in Examples 1-5 and the electron microscope images of the catalyst precursor Cu-LDH (the pH value of the reaction system is 10).

[0025] Figure 2 The XRD patterns and CuXPS patterns of the catalysts prepared under different atmospheres in Example 1 are shown.

[0026] Figure 3 The temperature-programmed desorption and pyridine infrared spectrum probe diagrams of the catalyst prepared under different atmospheres in Example 1 are shown.

[0027] Figure 4 This is a scanning electron microscope image of the catalyst prepared in Example 1.

[0028] Figure 5 Activity diagrams of the catalysts prepared in Example 1 and Examples 15 and 16. DETAILED DESCRIPTION

[0029] To further illustrate the catalyst for synthesizing acrylic acid from acetylene, its preparation method, and its application, and to achieve the intended purpose of the present invention, the following describes in detail the catalyst for synthesizing acrylic acid from acetylene, its preparation method, and its application, along with its specific embodiments, structure, features, and efficacy, in conjunction with preferred embodiments. In the following description, different references to "one embodiment" or "embodiment" do not necessarily refer to the same embodiment. Furthermore, specific features, structures, or characteristics of one or more embodiments may be combined in any suitable manner.

[0030] The following will further describe in detail a catalyst for synthesizing acrylic acid from acetylene, its preparation method, and its application in conjunction with specific embodiments of the present invention:

[0031] Copper-based heterogeneous catalysts have attracted much attention due to their environmentally friendly properties and low cost. Layered double hydroxides (LDHs) are layered structural materials that can be calcined to obtain layered double oxides (LDOs). Different functional materials can be obtained from LDHs, such as metal nanoparticles or mixed metal oxides with high dispersibility and thermal stability. The preparation of such structures generally involves topological transformations on the oxide matrix. Based on this, the technical solution of the present invention is proposed as follows:

[0032] A method for preparing a catalyst for synthesizing acrylic acid from acetylene comprises the following steps:

[0033] (1) After completely dissolving the copper salt, zinc salt, and aluminum salt in water, add a precipitant and stir the reaction for 0.5-2 hours to obtain a slurry;

[0034] (2) filtering the slurry, collecting the solid, washing, drying, and grinding to obtain the catalyst precursor Cu-LDH;

[0035] (3) calcining the catalyst precursor Cu-LDH at 300-500° C. for 3-6 hours to obtain the catalyst for synthesizing acrylic acid from acetylene.

[0036] Preferably, the molar ratio of the copper salt, zinc salt and aluminum salt is 0.5-2:1:1.

[0037] Preferably, in step (1), the copper salt is Cu(NO3)2, the zinc salt is Zn(NO3)2, and the aluminum salt is Al(NO3)3;

[0038] The precipitant is 0.5-1 mol / L sodium carbonate solution.

[0039] Preferably, in the step (1), NaOH solution is used to adjust the pH value of the reaction system to 8-11.

[0040] Further preferably, in the step (1), the pH value of the reaction system is 10-11.

[0041] Preferably, in step (3), the calcination atmosphere is air, hydrogen, or nitrogen.

[0042] Further preferably, in the step (3), the calcination atmosphere is nitrogen.

[0043] A catalyst for synthesizing acrylic acid from acetylene is prepared by the above-mentioned preparation method.

[0044] The catalyst for synthesizing acrylic acid from acetylene is used in catalyzing the carbonylation of C2H2 and CO to synthesize acrylic acid.

[0045] Example 1.

[0046] The specific steps are as follows:

[0047] (1) Preparation of catalyst

[0048] S1: At room temperature, 0.006 mol Cu(NO3)2, 0.006 mol Zn(NO3)2·6H2O, and 0.006 mol Al(NO3)3·9H2O were dissolved in 10 ml of deionized water to form a copper-zinc-aluminum mixed salt solution.

[0049] Dissolve 0.0125 mol Na2CO3 in 25 ml of deionized water.

[0050] S2: Slowly add Na2CO3 solution dropwise to the mixed salt solution, and adjust the pH to 9 with 1 mol / L NaOH solution during stirring. Aged at room temperature for 0.5 h to obtain a slurry.

[0051] S3: Filter the aged slurry and collect the solid phase. Place the solid phase in a funnel for suction filtration and rinse with deionized water three times. Dry the washed solid phase precipitate in air at 100°C and grind it into powder to obtain the catalyst precursor Cu-LDH.

[0052] S4: calcining the catalyst precursor Cu-LDH at 300° C. for 5 h under different atmospheres to obtain the catalyst Cu-LDO.

[0053] Cu-LDO(A) was obtained by calcination in air, Cu-LDO(H) was obtained by calcination in hydrogen, and Cu-LDO(N) was obtained by calcination in nitrogen.

[0054] The active metal loading of the catalyst Cu-LDO(N) was determined to be 21% and the metal dispersion was 20%.

[0055] (2) Application

[0056] Weigh 200 mg of catalyst, 1.5 g of NiBr2, 300 mL of solvent (tetrahydrofuran), and 15 mL of purified water, and add them into the reactor.

[0057] After closing the reactor, introduce nitrogen to 3 MPa and purge the pipeline. Repeat this process three times to ensure that all air in the reactor is completely exhausted.

[0058] Open the air inlet valve, first introduce 4.26L acetylene gas, then introduce carbon monoxide gas to 4MPa, and then close all inlet and outlet valves.

[0059] The holding time (225°C) and stirring rate (800 rpm) of the reactor were set to ensure normal operation of the reactor.

[0060] After the reaction is completed, turn on the cooling water to cool the reactor to room temperature.

[0061] First use a gas collection bag to collect the remaining reactor gas, then open the reactor to collect the liquid.

[0062] The collected gas and liquid were analyzed by gas chromatography and the data were recorded.

[0063] The collected liquid is filtered, washed, dried, and the reacted catalyst is collected.

[0064] Clean the reactor and prepare for the next experiment.

[0065] Example 2.

[0066] The steps for preparing the catalyst Cu-LDO(N) in Example 2 are the same as those in Example 1, except that in step S2, the pH is adjusted to 9.7 using a NaOH solution.

[0067] Example 3.

[0068] The steps for preparing the catalyst Cu-LDO(N) in Example 2 are the same as those in Example 1, except that in step S2, the pH is adjusted to 10 with a NaOH solution during the stirring process.

[0069] Example 4.

[0070] The steps for preparing the catalyst Cu-LDO(N) in Example 4 are the same as those in Example 1, except that in step S2, the pH is adjusted to 10.5 with a NaOH solution during the stirring process.

[0071] Example 5.

[0072] The steps for preparing the catalyst Cu-LDO(N) in Example 5 are the same as those in Example 1, except that in step S2, the pH is adjusted to 11 with a NaOH solution during the stirring process.

[0073] The method used in (2) of Example 1 was used to carry out the carbonylation of acetylene with the catalyst Cu-LDO(N) prepared in Example 1-5 at 225°C for acrylic acid. The selectivity and yield of acrylic acid are shown in Table 1.

[0074] Table 1 Screening of hydrotalcites prepared at different pH values

[0075] catalyst pH Selectivity (%) Yield (%) Example 1 9 50.2 43.4 Example 2 9.7 52.3 54.5 Example 3 10 54.5 49.8 Example 4 10.5 62.4 60.4 Example 5 11 53.2 50.2

[0076] As shown in Table 1, the pH of the catalyst preparation is between 10 and 11, and the prepared catalyst has good activity.

[0077] Example 6.

[0078] The operation steps are the same as those in Example 4, except that in step (2), 0.05 g of the catalyst Cu-LDO(N) is used to synthesize acrylic acid by carbonylation of acetylene.

[0079] Example 7.

[0080] The operation steps are the same as those in Example 4, except that in step (2), 0.10 g of the catalyst Cu-LDO(N) is used to synthesize acrylic acid by carbonylation of acetylene.

[0081] Example 8.

[0082] The operation steps are the same as those in Example 4, except that in step (2), 0.15 g of the catalyst Cu-LDO(N) is used to synthesize acrylic acid by carbonylation of acetylene.

[0083] Example 9.

[0084] The operation steps are the same as those in Example 4, except that in step (2), 0.25 g of the catalyst Cu-LDO(N) is used to synthesize acrylic acid by carbonylation of acetylene.

[0085] The method used in (2) of Example 1 was used to carry out an acrylic acid carbonylation experiment on acetylene using the catalyst Cu-LDO(N) prepared in Examples 6-9 at 225°C. The selectivity and yield of acrylic acid are shown in Table 2.

[0086] Table 2 Screening of catalysts of different qualities

[0087]

[0088]

[0089] It can be seen from Table 2 that when the catalyst mass is 0.1g, the reaction activity is better.

[0090] Example 10.

[0091] The operation steps are the same as those in Example 7. The difference is that in step (2), the volume of pure water is 10 ml.

[0092] Example 11.

[0093] The operation steps are the same as those in Example 7. The difference is that in step (2), the volume of pure water is 20 ml.

[0094] Example 12.

[0095] The operation steps are the same as those in Example 7. The difference is that in step (2), the volume of pure water is 25 ml.

[0096] Example 13.

[0097] The operation steps are the same as those in Example 7. The difference is that in step (2), the volume of pure water is 30 ml.

[0098] Using the method used in (2) of Example 1, the catalyst Cu-LDO(N) in Examples 10-14 was used to carry out acetylene carbonylation experiments on acrylic acid at 225°C. The selectivity and yield of acrylic acid are shown in Table 3.

[0099] Table 3 Screening of different volumes of water

[0100] catalyst Volume of water (mL) Selectivity (%) Yield (%) Example 10 10 67.8 70.2 Example 7 15 70.0 69.0 Example 11 20 84.0 80.5 Example 12 25 65.2 67.2 Example 13 30 56.3 59.0

[0101] It can be seen from Table 3 that the reaction activity is best when the volume of water is 20 mL.

[0102] Example 14: Preparation of Cu0.5-LDO(N)

[0103] The specific steps are as follows:

[0104] (1) Preparation of catalyst

[0105] S1: Dissolve 0.003 mol Cu(NO₃)₂, 0.006 mol Zn(NO₃)₂·6H₂O, and 0.006 mol Al(NO₃)₃·9H₂O in 10 ml of deionized water at room temperature to form a copper-zinc-aluminum mixed salt solution. The molar ratio of Cu(NO₃)₂, Zn(NO₃)₂·6H₂O, and Al(NO₃)₃·9H₂O is 0.5:1:1.

[0106] Dissolve 0.0125 mol of Na2CO3 in 25 ml of deionized water.

[0107] S2: Slowly add Na2CO3 solution dropwise to the mixed salt solution, and adjust the pH to 10 with 1 mol / L NaOH solution during stirring, and age at room temperature for 0.5 h to obtain a slurry.

[0108] S3: The aged slurry was filtered, and the solid phase was collected. The solid phase was repeatedly rinsed with deionized water three times. The washed solid phase precipitate was dried in an air atmosphere at 100° C. for 4 hours and then ground into powder to obtain the catalyst precursor Cu-LDH.

[0109] S4: calcining the catalyst precursor Cu-LDH at 300° C. for 5 h in a nitrogen atmosphere to obtain the catalyst Cu0.5-LDO(N).

[0110] (2) Application

[0111] The method of (2) in Example 11 was used to test the carbonylation of acrylic acid with acetylene using the catalyst Cu0.5-LDO(N) prepared in this example at 225°C, with a carbon monoxide partial pressure of 4 MPa.

[0112] Example 15: Preparation of Cu2-LDO(N)

[0113] The specific steps are as follows:

[0114] (1) Preparation of catalyst

[0115] S1: Dissolve 0.012 mol Cu(NO₃)₂, 0.006 mol Zn(NO₃)₂·6H₂O, and 0.006 mol Al(NO₃)₃·9H₂O in 10 ml of deionized water at room temperature to form a copper-zinc-aluminum mixed salt solution. The molar ratio of Cu(NO₃)₂, Zn(NO₃)₂·6H₂O, and Al(NO₃)₃·9H₂O is 2:1:1.

[0116] Dissolve 0.0125 mol of Na2CO3 in 25 ml of deionized water.

[0117] S2: Na2CO3 solution was slowly added dropwise to the mixed salt solution, and the pH was adjusted to 10 with 1 mol / L NaOH solution during stirring, and aged at room temperature for 0.5 h to obtain a slurry.

[0118] S3: The aged slurry was filtered, and the solid phase was collected. The solid phase was repeatedly rinsed with deionized water three times. The washed solid phase precipitate was dried in an air atmosphere at 100° C. for 4 hours and then ground into powder to obtain the catalyst precursor Cu-LDH.

[0119] S4: calcining the catalyst precursor Cu-LDH at 300° C. for 5 h in a nitrogen atmosphere to obtain the catalyst Cu2-LDO(N).

[0120] (2) Application

[0121] The method of (2) in Example 11 was used to test the carbonylation of acrylic acid with acetylene using the catalyst Cu2-LDO(N) prepared in this example at 225°C, with a carbon monoxide partial pressure of 4 MPa.

[0122] Example 16: The stability of the catalyst Cu2-LDO(N) prepared in this example was determined.

[0123] The method is as follows: the catalyst of Example 11 was collected, filtered, and dried after reaction. Acetylene carbonylation of acrylic acid was carried out under the same conditions as 225°C, 0.1g of catalyst, and 20ml of pure water. The carbon monoxide partial pressure was 4MPa. The results of the catalyst cycle test are shown in Table 4.

[0124] Table 4

[0125] Number of cycles Selectivity (%) Yield (%) 1 84.0 80.5 2 78.4 78.5 3 75.0 73.2

[0126] As can be seen from Table 4, although the performance of the Cu-LDO(N) catalyst prepared by the present invention decreased in the three experimental cycles, the decline was small and remained relatively stable.

[0127] Example 17: Catalyst Characterization Test

[0128] (1) Catalyst precursor Cu-LDH prepared at different pH values in Examples 1-5

[0129] Characterization method: X-ray diffraction (XRD, Ultima IV, Cu Kα radiation source The structures of the catalyst precursor Cu-LDH prepared at different pH values in Examples 1-5 were characterized.

[0130] The micromorphology of the catalyst precursor Cu-LDH in Example 3 (pH of the reaction system is 10) was observed using a scanning microscope (SEM, F430 and Hitachi SU8020).

[0131] Characterization results: Figure 1 The left figure shows that the sharp peaks corresponding to hydrotalcite at diffraction angles of 2θ = 11.6°, 23.3°, 34.5° and 60.1° are attributed to (003), (006), (009) and (110), respectively, with good crystallinity, confirming the successful preparation of hydrotalcite precursor under different pH conditions.

[0132] Figure 1 The right picture is a scanning electron microscope image, which shows that the hydrotalcite precursor has a good layered structure. The diffraction peak with the highest intensity corresponds to the copper-zinc-aluminum hydrotalcite, which indicates that there is a perfect crystal phase in the composite material. The structural comparison shows that

[0133] (2) Characterization of the catalyst of Example 1

[0134] Characterization method: X-ray diffraction (XRD, Ultima IV, Cu Kα radiation source The structures of Cu-LDO (A), Cu-LDO (H), and Cu-LDO (N) prepared in Example 1 were characterized. X-ray photoelectron spectroscopy (XPS, PHI5000 Versaprobe III) was used to further analyze the chemical valence state of the copper element.

[0135] Characterization results: Figure 2 The left image shows that after calcining the copper-aluminum hydrotalcite precursor at 300°C, the layered structure of the hydrotalcite precursor is destroyed, and the crystallinity of the catalyst is significantly reduced. At the same time, the catalyst structure collapses after calcination under different atmospheres, and the loaded copper ions are converted into different copper species.

[0136] Combine Figure 2 The right picture shows the analysis of Cu valence using XPS. The valence of copper will change after treatment under different gas atmospheres. After treatment under air atmosphere, the valence of copper is mainly CuO and Cu 2+ , after treatment in hydrogen and nitrogen atmosphere, CuO, Cu 2+ and Cu + Therefore, the purpose of changing the copper valence state is achieved by changing the roasting environment.

[0137] (3) Chemical composition analysis of the catalyst in Example 1

[0138] Characterization method: The chemical composition of the catalysts Cu-LDO(A), Cu-LDO(H), and Cu-LDO(N) prepared in Example 1 was analyzed by temperature-programmed desorption (TPD, AutoChem1 II 2920) and pyridine adsorption technology (Pyridine-FTIR).

[0139] Characterization results: Figure 3 TPD characterization shows that there are widespread distribution of neutral and weak acid sites in the catalyst, and the number of neutral and strong acid sites in the catalyst prepared under nitrogen atmosphere increases. This is because when the catalyst precursor is calcined under nitrogen, the copper ion clusters [CuOCu] 2+ Self-reduction reaction occurs to become Cu + , resulting in a significant increase in the L acid content of the catalyst, Cu 2+ The reduction of -OH makes it easier for the proton to escape and the amount of B acid increases. This is due to the presence of different copper species.

[0140] Pyridine-FTIR characterization results showed that the number of catalysts B, L and total acidic sites prepared under nitrogen atmosphere was higher than that of other catalysts.

[0141] (4) Scanning electron microscopy characterization of the catalyst in Example 1

[0142] Characterization method: The microstructure and elements of the catalyst synthesized in Example 1 were analyzed using a transmission electron microscope (TEM, Titan G260-300).

[0143] Characterization results: Figure 4 As shown, a and b are catalysts Cu-LDO (A), c and d are catalysts Cu-LDO (N), and e and f are catalysts Cu-LDO (H).

[0144] Combine Figure 4 The calcined LDO sample exhibits lamellar, granular, and plate-like crystals, indicating a gradual transition to a composite metal oxide and a slow collapse of the lamellar structure. This also suggests that the catalyst retains some of the hydrotalcite lamellar morphology. Copper elemental analysis revealed no small copper clusters or agglomerations of copper particles after nitrogen calcination, indicating that calcination under a nitrogen atmosphere improves the dispersion of copper species.

[0145] (5) Catalyst activity at different ratios

[0146] Method: The catalytic activity of the catalysts Cu-LDO(A), Cu-LDO(H), and Cu-LDO(N) prepared in Example 4, and the catalysts Cu0.5-LDO(N) and Cu2-LDO(N) prepared in Examples 14 and 15 were measured. The measurement method was the same as in Example 11, with a catalyst mass of 0.10 g and a volume of purified water of 20 ml.

[0147] Results: As shown in Table 5 and Figure 5 shown.

[0148] Table 5

[0149] catalyst Selectivity (%) Yield (%) Cu-LDO(A) 59.4 56.8 Cu-LDO(H) 57.1 60.1 Cu-LDO(N) 84.0 80.5 Cu0.5-LDO(N) 65.4 62.1 Cu2-LDO(N) 64.8 61

[0150] Figure 5 The activity diagrams of the catalysts prepared in Examples 4, 14 and 15 are shown in FIG. Figure 5 As shown in the figure, the catalyst with Cu:Zn:Al=1:1:1 prepared under nitrogen atmosphere has the best catalytic performance. This is because the catalyst prepared under nitrogen atmosphere has a higher content of Cu. + And enhance the dispersion of Cu, Cu + It can lower the energy barrier of the reaction and expose more acidic sites, which can reduce the passivation effect of C2H2.

[0151] Example 18.

[0152] The specific steps are as follows:

[0153] (1) Preparation of catalyst

[0154] S1: Dissolve 0.009 mol Cu(NO₃)₂, 0.006 mol Zn(NO₃)₂·6H₂O, and 0.006 mol Al(NO₃)₃·9H₂O in 15 ml of deionized water at room temperature to form a copper-zinc-aluminum mixed salt solution. The molar ratio of Cu(NO₃)₂, Zn(NO₃)₂·6H₂O, and Al(NO₃)₃·9H₂O is 1.5:1:1.

[0155] Dissolve 0.0125 mol of Na2CO3 in 12.5 ml of deionized water.

[0156] S2: Slowly add Na2CO3 solution dropwise to the mixed salt solution, and adjust the pH to 8 with 1 mol / L NaOH solution during stirring. Aged at room temperature for 2 h to obtain a slurry.

[0157] S3: The aged slurry was filtered, and the solid phase was collected. The solid phase was repeatedly rinsed with deionized water three times. The washed solid phase precipitate was dried in an air atmosphere at 100° C. for 4 hours and then ground into powder to obtain the catalyst precursor Cu-LDH.

[0158] S4: calcining the catalyst precursor Cu-LDH at 350° C. for 6 h in an air atmosphere to obtain a catalyst.

[0159] Example 19.

[0160] The specific steps are as follows:

[0161] (1) Preparation of catalyst

[0162] S1: At room temperature, 0.008 mol Cu(NO3)2, 0.006 mol Zn(NO3)2·6H2O, and 0.006 mol Al(NO3)3·9H2O were dissolved in 10 ml of deionized water to form a copper-zinc-aluminum mixed salt solution.

[0163] Dissolve 0.0125 mol Na2CO3 in 20 ml of deionized water.

[0164] S2: Na2CO3 solution was slowly added dropwise to the mixed salt solution, and the pH was adjusted to 10 with 1 mol / L NaOH solution during stirring. The mixture was aged at room temperature for 1 h to obtain a slurry.

[0165] S3: The aged slurry was filtered, and the solid phase was collected and rinsed three times with deionized water. The washed solid precipitate was dried in air at 90°C for 5 hours and then ground into powder to obtain the catalyst precursor Cu-LDH.

[0166] S4: calcining the catalyst precursor Cu-LDH at 500° C. for 3 h in an air atmosphere to obtain a catalyst.

[0167] The above is merely a preferred embodiment of the present invention and does not constitute any form of limitation to the embodiments of the present invention. Any simple modifications, equivalent changes, and modifications made to the above embodiments based on the technical essence of the embodiments of the present invention are still within the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for preparing a catalyst for synthesizing acrylic acid from acetylene, characterized in that: The following steps are involved: (1) After completely dissolving the copper salt, zinc salt, and aluminum salt in water, add a precipitant and stir the reaction for 0.5-2 hours to obtain a slurry; (2) filtering the slurry, collecting the solid, washing, drying, and grinding to obtain the catalyst precursor Cu-LDH; (3) calcining the catalyst precursor Cu-LDH at 300-500° C. for 3-6 hours to obtain the catalyst for synthesizing acrylic acid from acetylene.

2. The preparation method according to claim 1, characterized in that The molar ratio of the copper salt, the zinc salt and the aluminum salt is 0.5-2:1:

1.

3. The preparation method according to claim 1, characterized in that In the step (1), the copper salt is Cu(NO3)2, the zinc salt is Zn(NO3)2, and the aluminum salt is Al(NO3)3; The precipitant is 0.5-1 mol / L sodium carbonate solution.

4. The preparation method according to claim 1, characterized in that In the step (1), NaOH solution is used to adjust the pH value of the reaction system to 8-11.

5. The preparation method according to claim 4, characterized in that In the step (1), the pH value of the reaction system is 10-11.

6. The preparation method according to claim 1, characterized in that In the step (3), the calcination atmosphere is air, hydrogen, or nitrogen.

7. The preparation method according to claim 6, characterized in that In the step (3), the calcination atmosphere is nitrogen.

8. A catalyst for synthesizing acrylic acid from acetylene, characterized in that The invention is prepared by the preparation method according to any one of claims 1 to 7.

9. Use of the catalyst for synthesizing acrylic acid from acetylene according to claim 8 in catalyzing the carbonylation of C2H2 and CO to synthesize acrylic acid.

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