A process for the production of pentanediol by hydrolysis of furfuryl alcohol

Abstract

The application discloses a method for preparing pentanediol by hydrogenolysis of furfuryl alcohol, which uses furfuryl alcohol as raw material, and generates 1,2-pentanediol and 1,5-pentanediol by hydrogenolysis of the furfuryl alcohol under the action of a catalyst; the catalyst comprises copper, calcium, barium and silicon. The process and the catalyst can obtain high furfuryl alcohol conversion rate and 1,2-pentanediol yield, different catalysts participate in different reactions, can effectively inhibit other side reactions, the 1,2-pentanediol yield is high, and the catalyst has long service life.

Description

Technical Field

[0001] This invention belongs to the field of pentylene glycol preparation technology, specifically relating to a method for preparing pentylene glycol by hydrogenolysis of furfuryl alcohol. Background Technology

[0002] 1,2-Pentanediol, also known as 1,2-dihydroxypentane, is an important diol compound with wide applications in pesticides, chemicals, and daily chemical products. Furthermore, 1,2-Pentanediol can dissolve poorly soluble active ingredients, and its unique properties make it suitable for use in various skincare products such as creams, eye creams, lotions, baby care products, and sunscreens. However, due to limitations in raw materials and production technology, the synthesis of 1,2-Pentanediol is difficult, with low yields and high costs, severely restricting the development and application of some chemical products, such as propiconazole, in my country.

[0003] 1,5-Pentanediol, also known as 1,5-pentanediol, is an important diol compound, commonly used as a cutting oil, a solvent for special detergents, latex paints, inks, or a lubricant. It is also used in the manufacture of plasticizers, brake fluids, alkyd resins, and polyurethane resins. In comparison, 1,2-pentanediol possesses superior properties but is more difficult to manufacture. Therefore, when preparing pentanediol mixtures, it is desirable to improve the selectivity of 1,2-pentanediol in the feedstock to increase the economic efficiency of pentanediol production plants.

[0004] Typically, the C5 fraction produced by the petrochemical industry is used for fuel consumption, resulting in a very limited supply of 1-pentene and 1,2-epoxypentane, which are raw materials for the synthesis of 1,2-pentanediol. Consequently, the economic viability of synthesizing pentanediol using these raw materials is generally poor. Therefore, developing a low-cost, widely available process route is crucial for improving the competitiveness of 1,2-pentanediol products and is also a significant driving force for accelerating its application in downstream industries in China.

[0005] US Patent 20080064905 uses hydrogen cyanide and n-butyraldehyde as raw materials to react and obtain the corresponding cyanohydrin. Under acidic conditions, the product is hydrolyzed, and the hydrolysis product, α-hydroxypentanoic acid, is reduced to 1,2-pentanediol using a ruthenium- and rhenium-based noble metal catalyst. This method achieves a product yield of over 64.6% and a purity of over 98%. While this process yields a high amount of 1,2-pentanediol, the use of cyanide and the use of cyanohydrin as an intermediate makes the operation more challenging.

[0006] Chinese patent CN102180769A discloses a method for synthesizing 1,2-pentanediol. The method involves two steps. The first step uses n-butyraldehyde and paraformaldehyde as raw materials, with a thiazole salt as a catalyst, to react in the presence of alkali and solution to generate the intermediate product 1-hydroxy-2-pentanone. This intermediate product is then used to produce 1,2-pentanediol under the action of a Pd / C catalyst. This method achieves a product yield of up to 60% and a purity of over 98%. However, the use of a precious metal catalyst significantly increases the cost of industrial-scale operation.

[0007] Therefore, developing a low-cost and widely available process route is key to improving the competitiveness of pentanediol products, especially to further improve the selectivity of 1,2-pentanediol, and is also an important driving force for accelerating downstream applications in China.

[0008] Developing a catalyst with mild reaction conditions, low cost, high yield, long lifespan, and an environmentally friendly process route has become an urgent problem to be solved in the industry. Summary of the Invention

[0009] The purpose of this invention is to provide a method for preparing pentanediol from furfuryl alcohol by hydrogenolysis. Introducing an alkaline substance into the raw materials improves the stability of furfuryl alcohol, reduces polymer formation, effectively extends catalyst life, and allows for highly selective production of 1,2-pentanediol, thereby improving the process's economics. To achieve the above objective, the technical solution adopted by this invention is as follows:

[0010] A method for preparing pentanediol by hydrogenolysis of furfuryl alcohol, using furfuryl alcohol as a raw material, wherein furfuryl alcohol is hydrogenoly synthesized into 1,2-pentanediol and 1,5-pentanediol under the action of a catalyst.

[0011] Furfuryl alcohol undergoes hydrogenolysis of its carbon-oxygen bonds to produce 1,2-pentanediol and 1,5-pentanediol. Pentanediol can be further hydrogenated to 1-pentanol. The preparation method of this invention exhibits extremely high furfuryl alcohol conversion and reduces the selectivity for further hydrogenolysis to 1-pentanol. By adjusting the catalyst, the selectivity for the higher-value-added 1,2-pentanediol can be improved.

[0012] Preferably, the catalyst comprises copper, calcium, barium, and silicon, wherein, based on the total weight of the catalyst (100%), copper oxide is 10-20 wt%, calcium oxide is 10-20 wt%, barium oxide is 10-20 wt%, and silicon oxide is 40-60 wt%.

[0013] Preferably, the method for preparing the catalyst includes the following steps:

[0014] (1) Mix silica gel and water and add them to the reaction vessel;

[0015] (2) Add calcium salt solution, barium salt solution and precipitant into the reaction vessel for precipitation, and then age the precipitate to obtain precipitate slurry;

[0016] Preferably, the precipitation temperature is 50-80℃, the precipitation time is 0.5-2h, the precipitation pH is 5-8, the aging temperature is 60-90℃, and the aging time is 0.5-3h.

[0017] (3) The slurry is filtered, washed, dried and calcined to obtain the modified carrier;

[0018] Preferably, the drying temperature is 80-120℃, the drying time is 4-12h, the calcination temperature is 760-900℃, and the calcination time is 2-8h.

[0019] (4) The modified carrier is placed in a hydrothermal reactor and the copper salt solution is poured into the hydrothermal reactor for hydrothermal crystallization. Then, the catalyst is obtained by filtration, drying and calcination.

[0020] Preferably, the silicone is type B silicone or type C silicone or a mixture of the two, preferably a mixture of type B silicone and type C silicone, with a mass ratio of 1:10 to 1:5.

[0021] Preferably, the average particle size of the silica gel is 20-200 μm.

[0022] Preferably, in step (2), the calcium salt solution and the barium salt solution can be a mixture of the two.

[0023] Preferably, the precipitant is an alkali metal carbonate.

[0024] Preferably, the copper salt solution is an ammonia solution of copper, and more preferably, it is prepared by dissolving copper oxide in ammonia water.

[0025] Preferably, in step (4), the hydrothermal crystallization temperature is 140-180℃ and the crystallization time is 36-72h;

[0026] Preferably, in step (4), the roasting temperature is 450-650℃ and the roasting time is 2-6h.

[0027] Preferably, the catalyst is reduced before use. The reduction method of the catalyst is as follows: the catalyst is first dried in a nitrogen atmosphere, and then the catalyst is reduced in hydrogen.

[0028] The reduction process is as follows: the catalyst is dried at a temperature of 140-160℃, and then a mixture of hydrogen and nitrogen containing less than 10v% H2 is introduced for pre-reduction. The proportion of hydrogen in the hydrogen and nitrogen mixture is then increased sequentially until the volume fraction of hydrogen is 100%. Finally, the reduction is carried out at 210-230℃ in a hydrogen atmosphere for 2-4 hours.

[0029] Preferably, the solvent is 1-pentanol, a hydrogenolysis product, and no other substances need to be introduced. The 1-pentanol is purified through a subsequent separation process and then mixed with the feedstock furfuryl alcohol before being fed into the feed. The furfuryl alcohol concentration in the feedstock is 3-8 wt%.

[0030] Preferably, an auxiliary agent is also added to the reaction, said auxiliary agent being one or more selected from aniline, methylaniline, dimethylaniline, ethylaniline, and tetramethylguanidine, and preferably added in an amount of 10-100 ppm of the system mass.

[0031] Preferably, the hydrogenolysis reaction conditions are: reaction temperature 110-160℃, reaction pressure 1-5 MPa, and liquid hourly space velocity 0.1-1 h⁻¹. -1 The molar ratio of hydrogen to aldehyde is 1-30:1. The preferred reaction temperature is 125-145℃, the reaction pressure is 1-3 MPa, and the liquid hourly space velocity is 0.2-0.6 h⁻¹. -1 The molar ratio of hydrogen to aldehyde is 1-10:1.

[0032] Compared with the prior art, the present invention has the following advantages:

[0033] (1) Furfuryl alcohol is widely available in my country as a bio-based raw material. It is of great significance to vigorously develop downstream products of furfuryl alcohol and expand its application fields. Moreover, as a bio-based product, the preparation of 1,2-pentanediol using this process will have a higher market premium.

[0034] (2) The reaction product is used as the circulating liquid. By diluting the concentration of the raw material furfuryl alcohol, the production of the polymerization product is effectively reduced. Furthermore, by adding additives, the stability of the raw material furfuryl alcohol is improved, and the service life of the catalyst is increased.

[0035] (3) The catalyst preparation method described in this patent invention can effectively modify the catalyst with alkali and improve the alkalinity of the catalyst; and effectively improve the dispersion of the catalyst and improve the catalyst reaction activity by forming a complex of the active component. Detailed Implementation

[0036] The method of the present invention will be described in detail below with reference to embodiments, but is not limited to the embodiments.

[0037] Raw material source:

[0038] Type B silicone, Qingdao Meigao, MG-B-480 industrial grade.

[0039] Type C silicone, Qingdao Meigao, MG-C-300 industrial grade.

[0040] Furfuryl alcohol, Beijing Inokai Reagent Co., Ltd., analytical grade.

[0041] Example 1

[0042] Mix the 20-50μm silica carrier evenly. The carrier contains 4.6g of type B silica and 45.5g of type C silica. Add the mixed carrier to the reaction vessel, add 100ml of water to the vessel, and set the reaction temperature to 50℃.

[0043] A 0.5M solution was prepared by dissolving 58.6g of calcium nitrate and 34.1g of barium nitrate in 980ml of water, using 18wt% sodium carbonate as the precipitant. The mixed salt solution and precipitant were titrated into the reactor through two feed inlets in a parallel flow. The precipitation temperature was 50℃, the precipitation time was 2h, the pH of the precipitate was 5.5, and the solution was aged at 60℃ for 3h to obtain the precipitate.

[0044] The slurry was filtered, washed, dried at 120℃ for 4 hours, and calcined at 760℃ for 8 hours to obtain the modified carrier.

[0045] 10g of CuO was dissolved in 45g of ammonia water (20wt%). The modified support obtained was placed in a hydrothermal reactor, and the dissolved copper ammonia solution was poured into the hydrothermal reactor. The mixture was hydrothermally crystallized at 140℃ for 72h. After filtration and drying, the catalyst was calcined at 650℃ for 2h to obtain catalyst #1.

[0046] Example 2

[0047] Mix the 40-100μm silica carrier evenly. The carrier contains 6.5g of type B silica and 48.5g of type C silica. Add the mixed carrier to the reaction vessel, add 100ml of water to the vessel, and raise the reaction temperature to 65℃.

[0048] 43.9 g of calcium nitrate and 25.6 g of barium nitrate were dissolved in 1220 ml of water to prepare a 0.3 M solution, using 18 wt% sodium carbonate as the precipitant. The mixed salt solution and precipitant were titrated into the reactor through two feed inlets in a parallel flow. The precipitation temperature was 65 °C, the precipitation time was 1 h, the pH of the precipitate was 6.5, and it was then aged at 75 °C for 1.5 h to obtain the precipitate.

[0049] The slurry was filtered, washed, dried at 100℃ for 8 hours, and calcined at 830℃ for 5 hours to obtain the modified carrier.

[0050] 15g of CuO was dissolved in 49.5g of ammonia water (20wt%). The modified support obtained was placed in a hydrothermal reactor, and the dissolved copper ammonia solution was poured into the hydrothermal reactor. The mixture was hydrothermally crystallized at 160℃ for 48h. After filtration and drying, the catalyst was calcined at 550℃ for 4h to obtain catalyst #2.

[0051] Example 3

[0052] Mix the 50-100μm silica carrier evenly. The carrier contains 10.0g of type B silica and 50.0g of type C silica. Add the mixed carrier to the reaction vessel, add 100ml of water to the vessel, and raise the reaction temperature to 80℃.

[0053] 29.3 g of calcium nitrate and 17.1 g of barium nitrate were dissolved in 2440 ml of water to prepare a 0.1 M solution, using 18 wt% sodium carbonate as the precipitant. The mixed salt solution and precipitant were titrated into the reactor through two feed inlets in a parallel flow. The precipitation temperature was 80 °C, the precipitation time was 12 h, the pH of the precipitate was 7.5, and it was then aged at 90 °C for 0.5 h to obtain the precipitate.

[0054] The slurry was filtered, washed, dried at 80℃ for 12 hours, and calcined at 900℃ for 2 hours to obtain the modified carrier.

[0055] 20g of CuO was dissolved in 54g of ammonia water (20wt%). The modified support obtained was placed in a hydrothermal reactor, and the dissolved copper ammonia solution was poured into the hydrothermal reactor. The mixture was hydrothermally crystallized at 180℃ for 36h. After filtration and drying, the catalyst was calcined at 650℃ for 6h to obtain catalyst #3.

[0056] Example 4

[0057] Catalyst Reduction: Catalyst #1 was loaded into a fixed-bed hydrogenation reactor with a loading volume of 50 ml. The catalyst was filled with quartz sand both above and below. Reduction was required before use under a nitrogen and hydrogen mixture, maintaining a gas hourly space velocity (VHSV) of 500 h⁻¹ during the reduction process. -1 First, the reactor temperature is raised to 160℃ and N2 is introduced and kept at a constant temperature for 0.5h to remove the physical water adsorbed on the catalyst. Then, a mixture of hydrogen and nitrogen containing 5v% H2 is introduced for pre-reduction for 1h. After that, the proportion of hydrogen in the hydrogen and nitrogen mixture is gradually increased to 10v%, 50v%, and 100%, and the hot spot temperature of the catalyst bed is controlled not to exceed 280℃ during this process. Finally, the temperature is raised to 220℃ and reduction is carried out in a pure hydrogen atmosphere for 3h.

[0058] After catalyst reduction, the reaction proceeded. First, the catalyst was impregnated with 1-pentanol. Then, hydrogen gas was introduced to increase the reaction pressure in the reactor to 5 MPa. The reaction temperature was set to 110℃, the H2 / aldehyde molar ratio to be 30:1, and the furfuryl alcohol liquid hourly space velocity (LISH) to be 0.1 g / gh. The raw material furfuryl alcohol was diluted with pentanol to a concentration of 8 wt%. During the dilution process, aniline was added as an auxiliary agent at a rate of 0.005% of the diluted raw material weight.

[0059] Example 5

[0060] Catalyst reduction: Catalyst #2 was loaded into a fixed-bed hydrogenation reactor, with a loading volume of 50 ml. Reduction was required before use under a nitrogen and hydrogen mixture, maintaining a mixed gas hourly space velocity (VHSV) of 500 h⁻¹ during the reduction process. -1 First, the reactor temperature is raised to 160℃ and N2 is introduced and kept at a constant temperature for 0.5h to remove the physical water adsorbed on the catalyst. Then, a mixture of hydrogen and nitrogen containing 5v% H2 is introduced for pre-reduction for 1h. After that, the proportion of hydrogen in the hydrogen and nitrogen mixture is gradually increased to 10v%, 50v%, and 100%, and the hot spot temperature of the catalyst bed is controlled not to exceed 280℃ during this process. Finally, the temperature is raised to 220℃ and reduction is carried out in a pure hydrogen atmosphere for 3h.

[0061] After catalyst reduction, the reaction proceeded. First, the catalyst was impregnated with 1-pentanol. Then, hydrogen gas was introduced to increase the reaction pressure in the reactor to 3 MPa. The reaction temperature was set at 135℃, the H2 / aldehyde molar ratio was 20:1, and the furfuryl alcohol liquid hourly space velocity was 0.5 g / gh. The furfuryl alcohol feedstock was diluted with pentanol to a concentration of 5 wt%. During the dilution process, methylaniline was added as an auxiliary agent at a rate of 0.006% of the diluted feedstock weight.

[0062] Example 6

[0063] Catalyst reduction: Catalyst #3 was loaded into a fixed-bed hydrogenation reactor, with a loading volume of 50 ml. Reduction was required before use under a nitrogen and hydrogen mixture, maintaining a mixed gas hourly space velocity (VHSV) of 500 h⁻¹ during the reduction process. -1 First, the reactor temperature is raised to 160℃ and N2 is introduced and kept at a constant temperature for 0.5h to remove the physical water adsorbed on the catalyst. Then, a mixture of hydrogen and nitrogen containing 5v% H2 is introduced for pre-reduction for 1h. After that, the proportion of hydrogen in the hydrogen and nitrogen mixture is gradually increased to 10v%, 50v%, and 100%, and the hot spot temperature of the catalyst bed is controlled not to exceed 280℃ during this process. Finally, the temperature is raised to 220℃ and reduction is carried out in a pure hydrogen atmosphere for 3h.

[0064] After catalyst reduction, the reaction proceeded. First, the catalyst was impregnated with 1-pentanol. Then, hydrogen gas was introduced to raise the reaction pressure in the reactor to 1 MPa. The reaction temperature was set to 160℃, the H2 / aldehyde molar ratio to be 10:1, and the furfuryl alcohol liquid hourly space velocity (LISH) to be 1.0 g / gh. The furfuryl alcohol feedstock was diluted with pentanol to a concentration of 3 wt%. During the dilution process, dimethylaniline was added as an auxiliary agent at a rate of 0.010% of the diluted feedstock weight.

[0065] Example 7

[0066] Catalyst reduction: Catalyst #3 was loaded into a fixed-bed hydrogenation reactor, with a loading volume of 50 ml. Reduction was required before use under a nitrogen and hydrogen mixture, maintaining a mixed gas hourly space velocity (VHSV) of 500 h⁻¹ during the reduction process. -1 First, the reactor temperature is raised to 160℃ and N2 is introduced and kept at a constant temperature for 0.5h to remove the physical water adsorbed on the catalyst. Then, a mixture of hydrogen and nitrogen containing 5v% H2 is introduced for pre-reduction for 1h. After that, the proportion of hydrogen in the hydrogen and nitrogen mixture is gradually increased to 10v%, 50v%, and 100%, and the hot spot temperature of the catalyst bed is controlled not to exceed 280℃ during this process. Finally, the temperature is raised to 220℃ and reduction is carried out in a pure hydrogen atmosphere for 3h.

[0067] After catalyst reduction, the reaction proceeded. First, the catalyst was impregnated with 1-pentanol. Then, hydrogen gas was introduced to raise the reaction pressure in the reactor to 1 MPa. The reaction temperature was set at 160℃, the H2 / aldehyde molar ratio was 10:1, and the furfuryl alcohol liquid hourly space velocity was 1.0 g / gh. The furfuryl alcohol feedstock was diluted with pentanol to a concentration of 3 wt%. No additives were used during operation.

[0068] Comparative Example 1

[0069] The catalyst was prepared using the method of Example 1, without adding copper oxide as the active component, and 20% CaO-20BaO%-60% SiO2 was prepared as catalyst #4.

[0070] Catalyst Reduction: Catalyst #4 was loaded into a fixed-bed hydrogenation reactor with a loading volume of 50 ml. The catalyst was filled with quartz sand both above and below. Reduction was required before use under a nitrogen and hydrogen mixture, maintaining a gas hourly space velocity (VHSV) of 500 h⁻¹ during the reduction process. -1 First, the reactor temperature is raised to 160℃ and N2 is introduced and kept at a constant temperature for 0.5h to remove the physical water adsorbed on the catalyst. Then, a mixture of hydrogen and nitrogen containing 5v% H2 is introduced for pre-reduction for 1h. After that, the proportion of hydrogen in the hydrogen and nitrogen mixture is gradually increased to 10v%, 50v%, and 100%, and the hot spot temperature of the catalyst bed is controlled not to exceed 280℃ during this process. Finally, the temperature is raised to 220℃ and reduction is carried out in a pure hydrogen atmosphere for 3h.

[0071] After catalyst reduction, the reaction proceeded. First, the catalyst was impregnated with 1-pentanol. Then, the reaction pressure inside the reactor was increased to 5 MPa using hydrogen gas. The reaction temperature was set to 110℃, the H2 / aldehyde molar ratio to be 30:1, and the furfuryl alcohol liquid hourly space velocity (LISH) to be 0.1 g / gh. The furfuryl alcohol feedstock was diluted with pentanol to a concentration of 8 wt%.

[0072] Comparative Example 2

[0073] The catalyst was prepared using the method of Example 2, without adding calcium oxide as the active component, and 15% CuO-15BaO%-70% SiO2 was prepared as catalyst #5.

[0074] Catalyst reduction: Catalyst #5 was loaded into a fixed-bed hydrogenation reactor, with a loading volume of 50 ml. Reduction was required before use under a nitrogen and hydrogen mixture, maintaining a mixed gas hourly space velocity (VHSV) of 500 h⁻¹ during the reduction process. -1 First, the reactor temperature is raised to 160℃ and N2 is introduced and kept at a constant temperature for 0.5h to remove the physical water adsorbed on the catalyst. Then, a mixture of hydrogen and nitrogen containing 5v% H2 is introduced for pre-reduction for 1h. After that, the proportion of hydrogen in the hydrogen and nitrogen mixture is gradually increased to 10v%, 50v%, and 100%, and the hot spot temperature of the catalyst bed is controlled not to exceed 280℃ during this process. Finally, the temperature is raised to 220℃ and reduction is carried out in a pure hydrogen atmosphere for 3h.

[0075] After catalyst reduction, the reaction proceeded. First, the catalyst was impregnated with 1-pentanol. Then, hydrogen gas was introduced to increase the reaction pressure in the reactor to 3 MPa. The reaction temperature was set at 135℃, the H2 / aldehyde molar ratio was 20:1, and the furfuryl alcohol liquid hourly space velocity was 0.5 g / gh. The furfuryl alcohol feedstock was diluted with pentanol to a concentration of 5 wt%.

[0076] Comparative Example 3

[0077] The catalyst was prepared using the method of Example 3, without adding calcium oxide as the active component, and 20% CuO-10CaO%-70% SiO2 was prepared as catalyst #6.

[0078] Catalyst reduction: Catalyst #6 was loaded into a fixed-bed hydrogenation reactor, with a loading volume of 50 ml. Reduction was required before use under a nitrogen and hydrogen mixture, maintaining a mixed gas hourly space velocity (VHSV) of 500 h⁻¹ during the reduction process. -1 First, the reactor temperature is raised to 160℃ and N2 is introduced and kept at a constant temperature for 0.5h to remove the physical water adsorbed on the catalyst. Then, a mixture of hydrogen and nitrogen containing 5v% H2 is introduced for pre-reduction for 1h. After that, the proportion of hydrogen in the hydrogen and nitrogen mixture is gradually increased to 10v%, 50v%, and 100%, and the hot spot temperature of the catalyst bed is controlled not to exceed 280℃ during this process. Finally, the temperature is raised to 220℃ and reduction is carried out in a pure hydrogen atmosphere for 3h.

[0079] After catalyst reduction, the reaction proceeded. First, the catalyst was impregnated with 1-pentanol. Then, hydrogen gas was introduced to increase the reaction pressure in the reactor to 1 MPa. The reaction temperature was set to 160℃, the H2 / aldehyde molar ratio to be 10:1, and the furfuryl alcohol liquid hourly space velocity (LISH) to be 1.0 g / gh. The furfuryl alcohol feedstock was diluted with pentanol to a concentration of 3 wt%.

[0080] The conversion rate and selectivity of furfuryl alcohol hydrogenolysis in the examples and comparative examples are shown in Tables 1 and 2.

[0081] Table 1 Catalyst performance of examples

[0082]

[0083] Note: Catalyst performance after 200 hours

[0084] Table 2 Catalyst performance during long-term operation

[0085]

Claims

1. A method for preparing pentanediol by hydrogenolysis of furfuryl alcohol, characterized in that, Using furfuryl alcohol as a raw material, furfuryl alcohol is hydrogenated under the action of a catalyst to produce 1,2-pentanediol and 1,5-pentanediol; The catalyst includes copper, calcium, barium, and silicon.

2. The method according to claim 1, characterized in that, Based on a total catalyst weight of 100%, the composition is: copper oxide 10-20 wt%, calcium oxide 10-20 wt%, barium oxide 10-20 wt%, and silicon oxide 40-60 wt%.

3. The method according to claim 1 or 2, characterized in that, The method for preparing the catalyst includes the following steps: (1) Mix silica gel and water and add them to the reaction vessel; (2) Add calcium salt solution, barium salt solution and precipitant into the reaction vessel for precipitation, and then age the precipitate to obtain precipitate slurry; (3) The slurry is filtered, washed, dried and calcined to obtain the modified carrier; (4) The modified carrier is placed in a hydrothermal reactor and the copper salt solution is poured into the hydrothermal reactor for hydrothermal crystallization. Then, the catalyst is obtained by filtration, drying and calcination.

4. The method according to claim 3, characterized in that, The silicone is type B silicone, type C silicone, or a mixture of both, preferably a mixture of type B silicone and type C silicone, with a mass ratio of 1:10 to 1:

5. Preferably, the average particle size of the silica gel is 20-200 μm.

5. The method according to claim 3 or 4, characterized in that, In step (2), the calcium salt solution and the barium salt solution can be a mixture of the two; Preferably, in step (2), the precipitation temperature is 50-80℃, the precipitation time is 0.5-2h, the precipitation pH is 5-8, the aging temperature is 60-90℃, and the aging time is 0.5-3h. Preferably, the precipitant is an alkali metal carbonate.

6. The method according to any one of claims 3-5, characterized in that, In step (3), the drying temperature is 80-120℃, the drying time is 4-12h, the calcination temperature is 760-900℃, and the calcination time is 2-8h.

7. The method according to any one of claims 3-6, characterized in that, The copper salt solution is an ammonia solution of copper, preferably prepared by dissolving copper oxide in ammonia water; Preferably, in step (4), the hydrothermal crystallization temperature is 140-180℃ and the crystallization time is 36-72h; Preferably, in step (4), the roasting temperature is 450-650℃ and the roasting time is 2-6h.

8. The method according to any one of claims 1-7, characterized in that, The catalyst is reduced before use. The reduction method of the catalyst is as follows: the catalyst is first dried in a nitrogen atmosphere, and then the catalyst is reduced in hydrogen.

9. The method according to claim 8, characterized in that, The reduction method of the catalyst is as follows: the catalyst is dried in a nitrogen atmosphere at a temperature of 140-160℃, and then a mixture of hydrogen and nitrogen containing less than 10v% H2 is introduced for pre-reduction. The proportion of hydrogen in the hydrogen and nitrogen mixture is then increased sequentially until the volume fraction of hydrogen is 100%. Finally, the catalyst is reduced in a hydrogen atmosphere at 210-230℃ for 2-4 hours.

10. The method according to any one of claims 1-9, characterized in that, The solvent is 1-pentanol; Preferably, an auxiliary agent is also added to the reaction, which is one or more of aniline, methylaniline, dimethylaniline, ethylaniline and tetramethylguanidine, and preferably added in an amount of 10-100 ppm of the system mass; Preferably, the reaction temperature is 110-160℃, the reaction pressure is 1-5 MPa, and the liquid hourly space velocity is 0.1-1 h⁻¹. -1 The molar ratio of hydrogen to aldehyde is 1-30:1; More preferably, the reaction temperature is 125-145℃, the reaction pressure is 1-3 MPa, and the liquid hourly space velocity is 0.2-0.6 h⁻¹. -1 The molar ratio of hydrogen to aldehyde is 1-10:1.

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