A catalyst for the hydrogenation of propionaldehyde to n-propanol, its preparation method and application

Abstract

This application relates to the technical field of catalysts, and specifically discloses a catalyst for the hydrogenation of propionaldehyde to n-propanol, its preparation method and application. This application provides a catalyst for the hydrogenation of propionaldehyde to n-propanol, which is composed of the following components in weight ratio: CuO: ZnO: Al2O3: promoter = 20-45: 40-65: 0-10: 0.1-5; and Al2O3 is not 0; wherein, the promoter is selected from one or more of NiO, La2O3, and Cr2O3. The catalyst prepared by the technical solution of this application is applied to the reaction of hydrogenating propionaldehyde to n-propanol, the conversion rate of the propionaldehyde raw material is more than 99.1%, and the selectivity of n-propanol is more than 94.5%; and in the evaluation of the reaction process after using it for 400 h in the experiment of hydrogenating propionaldehyde to n-propanol, the catalyst has good stability.

Description

Technical Field

[0001] This application relates to the technical field of catalysts, and particularly relates to a catalyst for the hydrogenation of propionaldehyde to n-propanol, a preparation method thereof, and an application thereof. Background Art

[0002] At present, n-propanol is a very important chemical raw material with a wide variety of downstream products. For example, the downstream product n-propyl acetate, as an important organic solvent, is widely used in industries such as coatings, inks, color printing, tobacco packaging, flavors and fragrances, resins, etc. N-propanol is an intermediate for many pharmaceuticals, such as probenecid, sodium valproate, erythromycin, etc. In the agricultural aspect, n-propanol is an intermediate for herbicides; at the same time, n-propanol can be used as a coating solvent, a cosmetic solvent, a feed additive, etc. Therefore, n-propanol plays a very important role in many industries in today's society.

[0003] At present, the main industrial method for producing n-propanol is the oxo synthesis method of ethylene. First, propionaldehyde is synthesized from ethylene through carbonylation, and then it is obtained through reduction; there is also a part produced as a by-product of isopropanol and separated from the oxidation liquid of lower alkanes. The catalyst systems for the catalytic hydrogenation of propionaldehyde to propanol mainly include two types: copper-based and nickel-based. Compared with nickel-based catalysts, copper-based catalysts have a lower price and lower production costs. Therefore, there is a trend for propionaldehyde catalytic hydrogenation catalysts to develop towards copper-based, and domestic production devices also mostly use copper-based catalysts.

[0004] Related technologies disclose a catalyst for the gas-phase hydrogenation of propionaldehyde to propanol and a preparation method thereof. The main components of the catalyst contain copper oxide, zinc oxide, and alumina, and also contain a modification assistant, and the modification assistant is one or a mixture of two of metal element compounds such as potassium, magnesium, calcium, strontium, barium, etc. in the first and second main groups of the periodic table. In the hydrogenation reaction, it has high low-temperature activity, high propanol selectivity, and catalytic stability.

[0005] Related technologies also disclose a method for the catalytic hydrogenation of propionaldehyde to n-propanol using a nickel-based catalyst. In this scheme, the catalyst preparation uses an ammonia-induced deposition precipitation method, and the catalyst consists of a main active component, a metal assistant, and a carrier material. The main active component is Ni, the metal assistant is selected from one or several of metal elements such as Mg, Na, Ca, Co, or Ba, and the carrier material is selected from one or several of diatomite, white carbon black, MCM-41, SiO2 microspheres, SiO2 nanoparticles, or SBA-15. This catalyst has excellent low-temperature activity and n-propanol product selectivity, reducing the subsequent purification and separation costs of n-propanol products. However, a large amount of ammonia gas is released during the ammonia evaporation process, and the required time is relatively long, which is not environmentally friendly.

[0006] Higher reaction temperatures can lead to the polymerization of raw material propionaldehyde and aldol condensation, thereby reducing the selectivity of the target product n-propanol. Therefore, there is an urgent need to develop a catalyst for the hydrogenation of propionaldehyde to n-propanol that has a simple preparation method, is easy to operate, environmentally friendly, low-cost, and has excellent catalytic activity at low temperatures. Summary of the Invention

[0007] To solve the above technical problems, the present application provides a catalyst for the hydrogenation of propionaldehyde to n-propanol, its preparation method and application.

[0008] In the first aspect, the present application provides a catalyst for the hydrogenation of propionaldehyde to n-propanol, which is composed of the following components in weight ratio: CuO: ZnO: Al2O3: promoter = 20 - 45: 40 - 65: 0 - 10: 0.1 - 5; and Al2O3 is not 0.

[0009] Among them, the promoter is selected from one or more of NiO, La2O3, and Cr2O3.

[0010] Preferably, the catalyst for the hydrogenation of propionaldehyde to n-propanol is composed of the following components in weight ratio: CuO: ZnO: Al2O3: promoter = 35 - 45: 50 - 60: 3 - 7: 0.2 - 2.0.

[0011] In a specific embodiment, the catalyst for the hydrogenation of propionaldehyde to n-propanol is composed of the following components in weight ratio: CuO: ZnO: Al2O3: promoter = 40: 55: 5: 0.5.

[0012] Through experimental analysis, it can be seen that the present application controls the weight ratio between CuO: ZnO: Al2O3: promoter within the above range, further improving the performance of the catalyst.

[0013] Preferably, the catalyst for the hydrogenation of propionaldehyde to n-propanol is composed of the following components in weight ratio: CuO: ZnO: Al2O3: NiO: La2O3 = 35 - 45: 50 - 60: 3 - 7: 0.1 - 0.7: 0.8 - 1.3.

[0014] In a specific embodiment, the catalyst for the hydrogenation of propionaldehyde to n-propanol is composed of the following components in weight ratio: CuO: ZnO: Al2O3: NiO: La2O3 = 35 - 45: 50 - 60: 3 - 7: 0.5: 1.

[0015] Through experimental analysis, it can be seen that the type of promoter will significantly affect the catalytic performance of the catalyst; the present application selects NiO and La2O3 as promoters and controls the weight ratio between CuO: ZnO: Al2O3: NiO: La2O3 within the above range, further improving the performance of the catalyst.

[0016] Preferably, the catalyst further comprises a shaping agent, and the ratio between the sum of the weights of CuO, ZnO, Al2O3, and the promoter and the weight of the shaping agent is 100:2 - 4.

[0017] In a second aspect, the present application provides a method for preparing the above-mentioned catalyst for the hydrogenation of propionaldehyde to n-propanol. The catalyst is prepared by a co-precipitation method, and the specific steps are as follows:

[0018] (1) Weigh soluble copper salt, soluble zinc salt, soluble aluminum salt, and soluble promoter salt, dissolve them in water to prepare a mixed salt solution with a concentration of 1 - 1.5 mol / L, and simultaneously prepare an alkali solution with the same concentration as the mixed salt solution;

[0019] (2) Add the mixed salt solution and the alkali solution dropwise into the reaction vessel in parallel. During the dropping process, keep it under stirring conditions, with a water bath temperature of 70 - 90 °C and a constant pH value of 7 - 8 to obtain a slurry;

[0020] (3) Age the slurry in a water bath at a temperature of 70 - 90 °C for 3 - 5 h. After aging, filter to obtain a filter cake. Add water to the filter cake to make a slurry and then filter. Repeat this process 5 - 10 times to obtain a co-precipitation product; then dry it at 80 - 120 °C, grind it, granulate it, and calcine and decompose it at 300 - 600 °C for 3 - 5 h to obtain a decomposition product;

[0021] (4) Mix the decomposition product and the shaping agent evenly according to a weight ratio of 100:2 - 4, and press and shape it to obtain the catalyst.

[0022] In the present application, the mixed metal salt solution and the alkali solution are added dropwise into the container in parallel by the co-precipitation method. During the dropping process, maintain a certain stirring speed, a certain water bath temperature, and a constant pH value; the addition of the soluble salt of the metal promoter promotes the highly dispersed state of copper, avoids its agglomeration during the calcination and decomposition process, and the promoter can change the electronic structure of the active component Cu, thereby improving the catalytic performance.

[0023] Preferably, the soluble copper salt is selected from any one or more of copper chloride, copper sulfate, and copper nitrate;

[0024] The soluble zinc salt is selected from any one or more of zinc chloride, zinc sulfate, and zinc nitrate;

[0025] The soluble aluminum salt is selected from any one or more of aluminum chloride, aluminum sulfate, and aluminum nitrate;

[0026] The soluble salt of the promoter is selected from any one or more of nickel nitrate, lanthanum nitrate, and chromium nitrate;

[0027] The alkali solution is selected from any one or more of sodium carbonate solution, sodium bicarbonate solution, and sodium hydroxide solution;

[0028] The forming agent is graphite.

[0029] Preferably, in the mixed salt solution, the concentration of the soluble copper salt is 0.25 - 0.65 mol / L, the concentration of the soluble zinc salt is 0.37 - 0.81 mol / L, the concentration of the soluble aluminum salt is 0.019 - 0.20 mol / L, and the concentration of the soluble auxiliary salt is 0.0012 - 0.07 mol / L.

[0030] In a third aspect, the present application provides a method for using the above catalyst, and the catalyst needs to be subjected to reduction activation treatment before use; the process parameters of the reduction activation treatment are as follows:

[0031] Heat up to 110 - 130 °C at a heating rate of 20 - 40 °C / h, and the reduction atmosphere is pure N2; keep warm for 20 - 40 min, and increase the hydrogen concentration until the reduction atmosphere is 5% H2 + 95% N2;

[0032] Heat up to 175 - 185 °C at a heating rate of 5 - 15 °C / h, and the reduction atmosphere is 5% H2 + 95% N2; keep warm for 100 - 140 min, and increase the hydrogen concentration until the reduction atmosphere is 25% H2 + 75% N2;

[0033] Heat up to 195 - 205 °C at a heating rate of 4 - 6 °C / h, and increase the hydrogen concentration to the reduction atmosphere of 50% H2 + 50% N2, 70% H2 + 30% N2, 85% H2 + 15% N2, 100% H2 per hour while heating up; keep warm for 100 - 140 min, the reduction atmosphere is pure H2, and the reduction ends.

[0034] In a fourth aspect, the present application provides the application of the above catalyst in the hydrogenation of propionaldehyde to n-propanol.

[0035] In a fifth aspect, the present application provides a method for hydrogenating propionaldehyde to n-propanol, and the above catalyst is used in the method. The specific steps are as follows: Feed propionaldehyde into a continuous fixed-bed reactor at a mass space velocity of 0.3 - 2 h -1 and continuously feed H2, control the molar ratio of hydrogen to aldehyde to be 10 - 100:1, and carry out the reaction under the conditions of a reaction temperature of 100 - 170 °C and a reaction pressure of 0.3 - 0.6 MPa.

[0036] After the catalyst prepared by the technical solution of the present application is crushed and subjected to reduction activation treatment, it is applied to the reaction of hydrogenating propionaldehyde to n-propanol. The conversion rate of the propionaldehyde raw material is more than 99.1%, and the selectivity of n-propanol is more than 94.5%; and during the evaluation of the reaction process after using the catalyst for 400 h in the experiment of hydrogenating propionaldehyde to n-propanol, the catalyst has good stability.

[0037] In summary, the technical solution of this application has the following effects:

[0038] In this application, the mixed metal salt solution and the alkali solution are co-currently dropped into a container by the co-precipitation method. During the dropping process, a certain stirring speed, a certain water bath temperature, and a constant pH value are maintained. The addition of the metal promoter promotes the highly dispersed copper, avoids its agglomeration during the calcination and decomposition process, and the promoter can change the electronic structure of the active component Cu, improving the catalytic performance.

[0039] When the catalyst of this application is applied to the reaction of hydrogenating propionaldehyde to n-propanol, the conversion rate of the propionaldehyde raw material is above 99.1%, and the selectivity of n-propanol is above 94.5%; and in the evaluation of the reaction process after using it for 400 h in the experiment of hydrogenating propionaldehyde to prepare n-propanol, the catalyst has good stability.

[0040] The catalyst provided by this application for hydrogenating propionaldehyde to prepare n-propanol not only has a simple preparation method, easy operation, environmental friendliness, low cost, but also has excellent catalytic activity at low temperature and has good industrial application prospects. Detailed implementation manners

[0041] The following further describes this application in detail in combination with examples, comparative examples, and performance detection tests. These examples should not be construed as limiting the scope claimed by this application. Examples Example 1

[0042] Example 1 provides a catalyst for hydrogenating propionaldehyde to n-propanol and its preparation method.

[0043] The preparation method of the catalyst for hydrogenating propionaldehyde to n-propanol in Example 1 is as follows:

[0044] Weigh 120.8 g of copper nitrate trihydrate (0.5 mol), 202 g of zinc nitrate hexahydrate (0.679 mol), 36.8 g of aluminum nitrate nonahydrate (0.098 mol), and 1.95 g of nickel nitrate hexahydrate (0.007 mol), add 1284 mL of deionized water, and prepare a 1 mol / L mixed salt solution A.

[0045] Weigh 136.1 g of anhydrous sodium carbonate (1.29 mol), add 1284 mL of deionized water, and prepare a 1 mol / L alkali solution B.

[0046] The salt solution A and the alkali solution B are co-currently dropped into the reaction container through a peristaltic pump. During the dropping process, continuous stirring is carried out. During the dropping process, it is maintained at 130 rpm under stirring conditions, the water bath reaction temperature is 80 °C, and the pH value is controlled at 7.5. The obtained slurry is subjected to co-precipitation.

[0047] After coprecipitation, it was aged at 80 °C for 3 h. After aging, the precipitate slurry was filtered to obtain a filter cake, and the filter cake was slurried with water and filtered. This operation was repeated 8 times to obtain the coprecipitation product. Then it was dried at 100 °C for 6 h, ground, granulated, and calcined and decomposed at 350 °C for 3 h to obtain the decomposition product.

[0048] The decomposition product was mixed evenly with a graphite forming agent in a weight ratio of 100:2-4, and tableted to obtain the final catalyst.

[0049] Based on the weight ratio of the oxides, the catalyst was composed of the following components in the following weight ratios: CuO:ZnO:Al2O3:NiO = 40:55:5:0.5.

[0050] Examples 2-5

[0051] Examples 2-5 respectively provided a catalyst for the hydrogenation of propionaldehyde to n-propanol and its preparation method.

[0052] The differences between Examples 2-5 and Example 1 were as follows: the amounts of substances in the mixed salt solution were different, and the compositions of the prepared catalysts were different, as specifically shown below.

[0053] In Example 2: 0.253 mol of copper nitrate trihydrate, 0.802 mol of zinc nitrate hexahydrate, 0.002 mol of aluminum nitrate nonahydrate, and 0.067 mol of nickel nitrate hexahydrate were taken and added to deionized water to prepare a 1 mol / L mixed salt solution A.

[0054] Based on the weight ratio of the oxides, the catalyst was composed of the following components in the following weight ratios: CuO:ZnO:Al2O3:NiO = 20:65:0.1:5.

[0055] In Example 3: 0.443 mol of copper nitrate trihydrate, 0.741 mol of zinc nitrate hexahydrate, 0.059 mol of aluminum nitrate nonahydrate, and 0.027 mol of nickel nitrate hexahydrate were taken and added to deionized water to prepare a 1 mol / L mixed salt solution A. Based on the weight ratio of the oxides, the catalyst was composed of the following components in the following weight ratios: CuO:ZnO:Al2O3:NiO = 35:60:3:2.

[0056] In Example 4: 0.569 mol of copper nitrate trihydrate, 0.617 mol of zinc nitrate hexahydrate, 0.137 mol of aluminum nitrate nonahydrate, and 0.0027 mol of nickel nitrate hexahydrate were taken and added to deionized water to prepare a 1 mol / L mixed salt solution A. Based on the weight ratio of the oxides, the catalyst was composed of the following components in the following weight ratios: CuO:ZnO:Al2O3:NiO = 45:50:7:0.2.

[0057] In Example 5: 0.569 mol of copper nitrate trihydrate, 0.494 mol of zinc nitrate hexahydrate, 0.196 mol of aluminum nitrate nonahydrate, and 0.00135 mol of nickel nitrate hexahydrate were taken and added to deionized water to prepare a mixed salt solution A with a concentration of 1 mol / L. Calculated by the weight ratio of oxides, the catalyst was composed of the following components in the following weight ratios: CuO:ZnO:Al2O3:NiO = 45:40:10:0.1.

[0058] In the above examples, the remaining process parameters were the same as those in Example 1.

[0059] Examples 6 - 11

[0060] Examples 6 - 11 respectively provided a catalyst for the hydrogenation of propionaldehyde to n - propanol and its preparation method.

[0061] The differences between Examples 6 - 11 and Example 1 were as follows: the types of soluble salts of the promoters in the mixed salt solution were different, and the compositions of the prepared catalysts were different, as specifically shown below.

[0062] In Example 6: Calculated by the weight ratio of oxides, the catalyst was composed of the following components in the following weight ratios: CuO:ZnO:Al2O3:NiO:La2O3 = 40:55:5:0.1:1.3.

[0063] In Example 7: Calculated by the weight ratio of oxides, the catalyst was composed of the following components in the following weight ratios: CuO:ZnO:Al2O3:NiO:La2O3 = 40:55:5:0.5:1.0.

[0064] In Example 8: Calculated by the weight ratio of oxides, the catalyst was composed of the following components in the following weight ratios: CuO:ZnO:Al2O3:NiO:La2O3 = 40:55:5:0.7:0.8.

[0065] In Example 9: Calculated by the weight ratio of oxides, the catalyst was composed of the following components in the following weight ratios: CuO:ZnO:Al2O3:NiO:La2O3 = 40:55:5:1.0:0.5.

[0066] In Example 10: Calculated by the weight ratio of oxides, the catalyst was composed of the following components in the following weight ratios: CuO:ZnO:Al2O3:NiO:Cr2O3 = 40:55:5:0.5:1.0.

[0067] In Example 11: Calculated by the weight ratio of oxides, the catalyst was composed of the following components in the following weight ratios: CuO:ZnO:Al2O3:La2O3 = 40:55:5:1.4.

[0068] In the above examples, the remaining process parameters were the same as those in Example 1. Comparative Example

[0069] Comparative Examples 1-4

[0070] Comparative Examples 1-4 respectively provided a catalyst for the hydrogenation of propionaldehyde to n-propanol and a preparation method thereof.

[0071] Differences between Comparative Examples 1-4 and Example 1: The dosages of various substances in the mixed salt solution were different, and the compositions of the prepared catalysts were different, as specifically shown below.

[0072] In Comparative Example 1: 0.5 mol of copper nitrate trihydrate, 0.679 mol of zinc nitrate hexahydrate, and 0.098 mol of aluminum nitrate nonahydrate were weighed, and deionized water was added to prepare a 1 mol / L mixed salt solution A (without adding soluble promoter salts).

[0073] Based on the weight ratio of oxides, the catalyst was composed of the following components in the following weight ratios: CuO: ZnO: Al2O3: NiO = 40:55:5.

[0074] In Comparative Example 2: 0.190 mol of copper nitrate trihydrate, 0.864 mol of zinc nitrate hexahydrate, 0.001 mol of aluminum nitrate nonahydrate, and 0.108 mol of nickel nitrate hexahydrate were taken, and deionized water was added to prepare a 1 mol / L mixed salt solution A.

[0075] Based on the weight ratio of oxides, the catalyst was composed of the following components in the following weight ratios: CuO: ZnO: Al2O3: NiO = 15:70:0.05:8.

[0076] In Comparative Example 3: 0.632 mol of copper nitrate trihydrate, 0.370 mol of zinc nitrate hexahydrate, 0.235 mol of aluminum nitrate nonahydrate, and 0.0007 mol of nickel nitrate hexahydrate were taken, and deionized water was added to prepare a 1 mol / L mixed salt solution A.

[0077] Based on the weight ratio of oxides, the catalyst was composed of the following components in the following weight ratios: CuO: ZnO: Al2O3: NiO = 50:30:12:0.05.

[0078] In Comparative Example 4: 0.632 mol of copper nitrate trihydrate, 0.370 mol of zinc nitrate hexahydrate, 0.235 mol of aluminum nitrate nonahydrate, and 0.0125 mol of magnesium nitrate hexahydrate were taken, and deionized water was added to prepare a 1 mol / L mixed salt solution A.

[0079] Based on the weight ratio of oxides, the catalyst was composed of the following components in the following weight ratios: CuO: ZnO: Al2O3: MgO = 50:30:12:0.05.

[0080] The remaining process parameters in the above comparative examples were the same as those in Example 1.

[0081] Performance detection test

[0082] (1)Catalyst performance detection

[0083] Using the catalysts provided by the above-mentioned examples and comparative examples respectively to prepare n-propanol, so as to evaluate and analyze the catalytic performance of the above-mentioned catalysts. The detection results are shown in Table 1.

[0084] The evaluation method is as follows:

[0085] Crush the above-mentioned catalyst into 20-40 mesh particles, weigh 20 mL and load it into the reaction tube. The height of the catalyst bed is 10 cm, and the raw material used is industrial propionaldehyde. A Shimadzu gas chromatograph is used for qualitative and quantitative analysis of the product components. The catalyst is subjected to reduction activation treatment before use, and the process parameters are:

[0086] Heat up to 120 °C at a heating rate of 30 °C / h, and the reduction atmosphere is pure N2; keep the temperature for 30 min, and increase the hydrogen concentration until the reduction atmosphere is 5% H2 + 95% N2;

[0087] Heat up to 180 °C at a heating rate of 10 °C / h, and the reduction atmosphere is 5% H2 + 95% N2; keep the temperature for 120 min, and increase the hydrogen concentration until the reduction atmosphere is 25% H2 + 75% N2;

[0088] Heat up to 200 °C at a heating rate of 5 °C / h, and increase the hydrogen concentration to the reduction atmosphere of 50% H2 + 50% N2, 70% H2 + 30% N2, 85% H2 + 15% N2, 100% H2 per hour while heating up; keep the temperature for 120 min, and the reduction atmosphere is pure H2, and the reduction is completed.

[0089] Under the conditions of a temperature of 110 °C and a pressure of 0.5 MPa, pass propionaldehyde into a continuous fixed-bed reactor at a mass space velocity of 0.3-2 h -1 and continuously pass in H2, control the hydrogen-to-aldehyde molar ratio to 10-100:1, and carry out the hydrogenation reaction. The calculation results of the raw material conversion rate and product selectivity are shown in Table 1.

[0090] (2)Stability evaluation

[0091] Use the catalysts prepared in the examples and comparative examples in the experiment of hydrogenating propionaldehyde to prepare n-propanol for 400 h, detect the catalytic performance of the catalyst, and then evaluate the stability of the catalyst. Propionaldehyde raw material conversion rate stability = propionaldehyde raw material conversion rate after the catalyst is used for 400 h / propionaldehyde raw material conversion rate of the initial catalyst × 100%; n-propanol product selectivity stability = n-propanol product selectivity after the catalyst is used for 400 h / n-propanol product selectivity of the initial catalyst × 100%;

[0092] Table 1 Detection Results of Catalyst Performance in Examples and Comparative Examples

[0093]

[0094] As can be seen from Table 1, the catalysts prepared in the examples of the present application have good performance, with the conversion rate of propionaldehyde raw material being more than 99.1% and the selectivity of n-propanol being more than 94.5%; and in the evaluation of the reaction process after using the catalyst for 400 h in the experiment of hydrogenating propionaldehyde to prepare n-propanol, the catalyst has good stability.

[0095] By comparing the detection results of Example 1 and Comparative Example 1, it can be seen that the catalyst prepared in Comparative Example 1 did not add a promoter, with the catalyst conversion rate being 89.3% and the selectivity of n-propanol being 86.7%.

[0096] By comparing the detection results of Example 1 and Comparative Examples 2-3, it can be seen that the weight ratio between the raw material components in the catalyst will significantly affect the catalytic performance of the catalyst. The catalyst prepared in Comparative Example 2 is composed of components with the following weight ratio: CuO:ZnO:Al2O3:promoter = 15:70:0.05:8, with the catalyst conversion rate being 88.4% and the selectivity of n-propanol being 82.4% respectively; the catalyst prepared in Comparative Example 3 is composed of components with the following weight ratio: CuO:ZnO:Al2O3:promoter = 50:30:12:0.05, with the catalyst conversion rate being 91.4% and the selectivity of n-propanol being 83.5% respectively. In contrast, the catalyst for hydrogenating propionaldehyde to prepare n-propanol in the present application is composed of CuO:ZnO:Al2O3:promoter components with a weight ratio of 20-45:40-65:0-10:0.1-5, and the prepared catalyst has good catalytic performance and stability.

[0097] Furthermore, by comparing the detection results of Examples 1-5, the present application selects to control the weight ratio between CuO:ZnO:Al2O3:promoter to be 35-45:50-60:3-7:0.2-2.0, further improving the performance of the catalyst.

[0098] By comparing the detection results of Example 1 and Comparative Example 4, it can be seen that the type of promoter will significantly affect the catalytic performance of the catalyst. The catalyst prepared in Comparative Example 4 is composed of components with the following weight ratio: CuO:ZnO:Al2O3:MgO = 50:30:12:0.05, that is, the promoter is MgO, and the prepared catalyst has a conversion rate of 99.1% and a selectivity of n-propanol of 96.1%; however, after using the catalyst for 400 h in the experiment of hydrogenating propionaldehyde to prepare n-propanol, the stability of the catalyst is poor. In contrast, the promoter in the present application is selected from one or more of NiO, La2O3, and Cr2O3, and the prepared catalyst has good catalytic performance and stability.

[0099] Furthermore, by comparing the detection results of Example 1 with those of Examples 6-11, the present application selects NiO and La2O3 as additives, and controls the weight ratio between CuO:ZnO:Al2O3:NiO:La2O3 to be 35-45:50-60:3-7:0.1-0.7:0.8-1.3, further improving the performance of the catalyst.

[0100] Although the present invention has been described in detail with general descriptions and specific embodiments above, based on the present invention, some modifications or improvements can be made, which are obvious to those skilled in the art. Therefore, these modifications or improvements made without departing from the spirit of the present invention all fall within the scope of the present invention claimed.

Claims

1. An application of a catalyst in hydrogenating propionaldehyde to produce n-propanol, characterized in that: The catalyst consists of CuO, ZnO, Al2O3, NiO, La2O3 and a molding agent; wherein the weight ratio of CuO, ZnO, Al2O3, NiO and La2O3 is 35-45:50-60:3-7:0.1-0.7:0.8-1.

3.

2. The use of the catalyst according to claim 1 in preparing n-propanol by hydrogenation of propionaldehyde, characterized in that: The ratio between the sum of the weights of the CuO, ZnO, Al2O3, NiO and La2O3 and the weight of the molding agent is 100:2-4.

3. The use of the catalyst according to any one of claims 1 to 2 in the hydrogenation of propionaldehyde to produce n-propanol, characterized in that: The catalyst is prepared by a coprecipitation method, and the specific steps are: (1) Weigh soluble copper salt, soluble zinc salt, soluble aluminum salt and soluble auxiliary salt and dissolve them in water to prepare a 1-1.5 mol / L mixed salt solution, and at the same time prepare an alkaline solution with the same concentration as the mixed salt solution; The soluble auxiliary salt is nickel nitrate or lanthanum nitrate; (2) adding the mixed salt solution and the alkaline solution dropwise to a reaction vessel in parallel, maintaining the addition process under stirring, a water bath temperature of 70-90° C., and a constant pH value of 7-8 to obtain a slurry; (3) aging the slurry at a water bath temperature of 70-90° C. for 3-5 hours, filtering after aging to retain the filter cake, adding water to the filter cake to slurry and filtering, repeating the process 5-10 times to obtain a coprecipitated product; then drying at 80-120° C., grinding, granulating, and calcining at 300-600° C. for 3-5 hours to obtain a decomposition product; (4) The decomposition product and the molding agent are uniformly mixed in a weight ratio of 100:2-4, and pressed into tablets to obtain a catalyst.

4. The use of the catalyst according to claim 3 in hydrogenating propionaldehyde to produce n-propanol, characterized in that: The soluble copper salt is selected from any one or more of copper chloride, copper sulfate, and copper nitrate; The soluble zinc salt is selected from any one or more of zinc chloride, zinc sulfate and zinc nitrate; The soluble aluminum salt is selected from any one or more of aluminum chloride, aluminum sulfate, and aluminum nitrate; The soluble auxiliary salt is nickel nitrate or lanthanum nitrate; The alkaline solution is selected from any one or more of sodium carbonate solution, sodium bicarbonate solution and sodium hydroxide solution; The molding agent is graphite.

5. The use of the catalyst according to claim 3 in hydrogenating propionaldehyde to produce n-propanol, characterized in that: In the mixed salt solution, the concentration of soluble copper salt is 0.25-0.65 mol / L, the concentration of soluble zinc salt is 0.37-0.81 mol / L, the concentration of soluble aluminum salt is 0.019-0.20 mol / L, and the concentration of soluble auxiliary agent salt is 0.0012-0.07 mol / L.

6. Use of the catalyst according to any one of claims 1 to 2 in hydrogenating propionaldehyde to produce n-propanol, characterized in that: The catalyst needs to be reduced and activated before use; the process parameters of the reduction and activation treatment are: Heat up to 110-130°C at a heating rate of 20-40°C / h, with pure N2 as the reducing atmosphere; keep warm for 20-40 minutes, and increase the hydrogen concentration to 5% H2+95% N2 as the reducing atmosphere; Heat up to 175-185°C at a heating rate of 5-15°C / h, with a reducing atmosphere of 5% H2+95% N2; keep warm for 100-140 minutes, and increase the hydrogen concentration to a reducing atmosphere of 25% H2+75% N2; The temperature was raised to 195-205°C at a heating rate of 4-6°C / h, and the hydrogen concentration was increased in sequence to a reducing atmosphere of 50% H2+50% N2, 70% H2+30% N2, 85% H2+15% N2, and 100% H2; the temperature was kept at 100-140 min, and the reducing atmosphere was pure H2, and the reduction was completed.

7. Use of the catalyst according to any one of claims 1 to 2 in hydrogenating propionaldehyde to produce n-propanol, characterized in that: The specific steps are: propionaldehyde at 0.3-2h -1 The mass space velocity is introduced into a continuous fixed bed reactor, and H2 is continuously introduced to control the molar ratio of hydrogen to aldehyde to be 10-100:

1. The reaction is carried out at a reaction temperature of 100-170°C and a reaction pressure of 0.3-0.6MPa.

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