A copper-based catalyst for preparing neopentyl glycol by hydrogenation and a preparation method thereof

Abstract

The application provides a copper-based catalyst for preparing neopentyl glycol by a hydrogenation method and a preparation method thereof, and belongs to the technical field of catalysts.The copper-based catalyst is an oxygen vacancy stable silicon nanotube modified high dispersion supported copper-silicon catalyst, and the composition of the copper-based catalyst is 20-55% of copper oxide, 5-25% of cerium oxide, 1-15% of silicon nanotubes and 10-50% of silicon oxide in terms of the weight percentage of the copper-based catalyst.The catalyst prepared by the application has good activity, the conversion rate of hydroxy pivalaldehyde is close to 99% and the selectivity of neopentyl glycol is close to 97% under a low hydrogen / aldehyde ratio, the catalyst has high stability and maintains high activity after being used for more than 1200 hours, the molar ratio of hydrogen to hydroxy pivalaldehyde is low, the hydrogen circulation is reduced, the energy consumption is lowered, and good technical effects are achieved.

Description

Technical Field

[0001] This invention belongs to the field of catalyst technology, specifically relating to a copper-based catalyst for the hydrogenation preparation of neopentyl glycol and its preparation method. Background Technology

[0002] Neopentyl glycol (NPG) is a unique diol that readily undergoes various chemical reactions such as esterification, oxidation, and condensation. Its special and stable neopentyl structure endows downstream products with excellent chemical stability, corrosion resistance, and hydrolysis resistance, and it is widely used in the synthesis of polyester resins, lubricants, plasticizers, pharmaceuticals, pesticides, and other fields.

[0003] The main industrial production routes for neopentyl glycol are disproportionation and condensation hydrogenation. Disproportionation, as the primary method for early industrial production of neopentyl glycol, relies on liquid alkali-catalyzed condensation and disproportionation reactions, but it has been gradually phased out due to problems with wastewater treatment and byproduct separation. Hydrogenation is currently the most advanced production process for neopentyl glycol. Under the catalysis of organic amines, formaldehyde and isobutyraldehyde undergo a condensation reaction to obtain hydroxyneopental (HPA). HPA is further hydrogenated to obtain NPG. This reaction is atom-economical, and the resulting neopentyl glycol is of high quality with low production costs.

[0004] Hydrogenation catalysts for hydroxypentanal (HPA) are one of the key challenges hindering the advancement of NPG industrial production technology. Copper-based catalysts have become the mainstream catalysts for HPA hydrogenation due to their good selective hydrogenation performance and relatively low cost. According to publicly reported patents CN102311313B and CN102249854B, the selectivity of existing copper-based catalysts needs improvement, while results from CN116920845A, CN117983307A, and CN105727958A show a high hydrogen-aldehyde ratio during hydrogenation. Improving catalyst selectivity and extending catalyst lifespan are urgent problems to be solved in the current hydrogenation of hydroxypentanal to neopentyl glycol catalysts. Summary of the Invention

[0005] In view of this, and addressing the issues of insufficient selectivity and high hydrogen-to-aldehyde ratio in the hydrogenation of hydroxypentanal to neopentyl glycol using existing copper-based catalysts, this invention provides a copper-based catalyst and its preparation method for the hydrogenation process of neopentyl glycol. This invention obtains an active precursor for the hydrogenation of hydroxypentanal by adding cerium to a copper-based catalyst. High-specific-surface-area silicon nanotubes modify silica gel as the catalyst support. The mixture yields the copper-based catalyst. The high-specific-surface-area composite support improves the dispersion of the active components, and the hydrogen enrichment effect of the nanotube channels reduces the hydrogen-to-aldehyde ratio. The addition of cerium generates oxygen vacancies, optimizing the surface activity of the catalyst by increasing the Cu content. 0 / Cu + The formulation ratio greatly improves catalytic performance.

[0006] To achieve the above objectives, this application first provides a copper-based catalyst for the preparation of neopentyl glycol by hydrogenation. The copper-based catalyst is a highly dispersed supported copper-silicon catalyst modified with oxygen vacancy-stabilized silicon nanotubes. The composition of the copper-based catalyst, by weight percentage, is 20%~55% copper oxide, 5%~25% cerium oxide, 1%~15% silicon nanotubes, and 10%~45% silicon oxide.

[0007] Preferably, the copper-based catalyst comprises, by weight percentage, 30% to 50% copper oxide, 10% to 25% cerium oxide, 5% to 15% silicon nanotubes, and 15% to 40% silicon oxide.

[0008] The present invention also provides a method for preparing the copper-based catalyst as described above, comprising the following steps:

[0009] (1) Weigh copper nitrate and cerium nitrate according to the element ratio of the target catalyst. Dissolve copper nitrate and cerium nitrate in deionized water at room temperature and stir evenly to obtain a mixed solution of active component precursors. Cerium is an important component in the catalyst of this invention. The addition of an appropriate amount of cerium promoter introduces oxygen vacancies to stabilize the active phase Cu. + This enhances the interaction between the active component and the support, thereby improving the selectivity and stability of the catalyst.

[0010] (2) At 20~60℃, add an acidic aqueous solution to the sodium silicate aqueous solution and control the final pH value to 7.0~8.5 to prepare silica gel; (3) According to the element ratio of the target catalyst, measure the active component precursor mixture solution and silica gel, and add the active component precursor mixture solution and precipitant solution to the silica gel in parallel at 40~85℃, control the pH to 6~10, and obtain a mixed suspension. (4) According to the element ratio of the target catalyst, measure the aqueous solution of silicon nanotubes and the mixed suspension, add the aqueous solution of silicon nanotubes to the mixed suspension under continuous stirring, age and then load it into the reaction vessel for hydrothermal crystallization to obtain the catalyst precursor. Silicon nanotubes are another key component in the catalyst of this invention. Due to their special one-dimensional tubular structure and confinement characteristics, they can increase the specific surface area of ​​the catalyst and improve the dispersion of the active component, while their pores can enrich hydrogen and exhibit good catalytic activity at a low hydrogen-aldehyde ratio.

[0011] (5) The catalyst precursor is filtered, washed, dried, calcined and shaped to obtain the copper-based catalyst.

[0012] Preferably, the copper salt and cerium salt in step (1) are selected from one or more of nitrates, sulfates, chlorides, acetates, oxalates and bromides; the concentration of copper salt in the active component precursor mixed solution is 0.1~0.8M.

[0013] Preferably, the acidic aqueous solution in step (2) is one of hydrochloric acid, sulfuric acid, or acetic acid aqueous solution; the content of silicon dioxide in the sodium silicate aqueous solution is 7~12wt%.

[0014] Preferably, the precipitant in step (3) is one or more of sodium carbonate, potassium carbonate, sodium bicarbonate, ammonia, ammonium bicarbonate and sodium hydroxide; the concentration of the precipitant solution is 0.2~1.5M.

[0015] Preferably, in step (4), the concentration of silicon nanotubes in the aqueous solution is 1-10 wt%; the length of the silicon nanotubes is 10-250 nm and the diameter is 1-10 nm; the aging temperature is 60-80 °C; the aging time is 1-8 h; the hydrothermal crystallization temperature is 100-200 °C; and the time is 4-24 h.

[0016] Preferably, the drying temperature in step (5) is 90~130℃ and the time is 12~36 hours; the calcination temperature is 350~650℃ and the time is 2~8 hours.

[0017] Finally, the present invention also provides the application of the copper-based catalyst used in the preparation of neopentyl glycol by the above hydrogenation method in the preparation of neopentyl glycol. The copper-based catalyst needs to be activated before use. The activation temperature is 250~350℃, the activation atmosphere is H2, or a mixture of H2 and N2, Ar, He inert gases, wherein the volume percentage of hydrogen is 5~80%, and the activation time is 10~20h.

[0018] In summary, this invention provides a copper-based catalyst for the hydrogenation preparation of neopentyl glycol and its preparation method. Compared with the prior art, its advantages are as follows: The catalyst exhibits good activity, achieving a single-pass conversion rate of nearly 99% for hydroxypentylaldehyde and a selectivity of nearly 97% for neopentyl glycol at a low hydrogen-to-aldehyde ratio. It also demonstrates high stability, maintaining high activity even after more than 1200 hours of use. The low molar ratio of hydrogen to hydroxypentylaldehyde reduces hydrogen recycling, lowers energy consumption, and achieves good technical results. Attached Figure Description

[0019] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort.

[0020] Figure 1 The image shown is a transmission electron microscope (TEM) image of the sample prepared in Example 3. Detailed Implementation

[0021] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0022] Example 1 A catalyst was prepared with a composition of 40% copper oxide, 20% cerium oxide, 5% silicon nanotubes, and 35% silicon oxide.

[0023] (1) Weigh copper nitrate and cerium nitrate according to the element ratio of the target catalyst. Dissolve copper nitrate and cerium nitrate in deionized water at room temperature and stir evenly to obtain a mixed solution of active component precursor. Control the concentration of copper nitrate to 0.2M. (2) At 20°C, dilute hydrochloric acid aqueous solution was added to 9wt% (calculated as silicon dioxide) sodium silicate aqueous solution to control the final pH value to 7.5, and silica gel was prepared. (3) According to the element ratio of the target catalyst, measure the active component precursor mixture solution and silica gel, and add the active component precursor mixture solution and precipitant solution (sodium carbonate solution, 0.5M) to the silica gel in parallel at 50°C, control the pH to 8, and obtain a mixed suspension. (4) According to the elemental ratio of the target catalyst, measure 2wt% of an aqueous solution of silicon nanotubes (length ~150nm, diameter ~4nm) and a mixed suspension. Under continuous stirring, add the aqueous solution of 2wt% silicon nanotubes to the mixed suspension. After aging at 70°C for 4 hours, load it into a reaction vessel and then into a hydrothermal reactor at 150°C for 16 hours to obtain the catalyst precursor. (5) The catalyst precursor was filtered and washed, the filtrate had a conductivity of 500 μS / cm, dried at 110°C for 13 hours, and then calcined in a muffle furnace at 550°C for 7 hours. The filtrate was then sheeted into plates (Ø5.1 mm). The copper-based catalyst A was prepared by cutting a sample from a depth of 5.0 mm.

[0024] Example 2 A catalyst was prepared with a composition of 35% copper oxide, 15% cerium oxide, 10% silicon nanotubes, and 40% silicon oxide.

[0025] (1) Weigh copper nitrate and cerium nitrate according to the element ratio of the target catalyst. Dissolve copper nitrate and cerium nitrate in deionized water at room temperature and stir evenly to obtain a mixed solution of active component precursor. Control the concentration of copper nitrate to 0.2M. (2) At 25°C, dilute hydrochloric acid aqueous solution was added to 9wt% (calculated as silicon dioxide) sodium silicate aqueous solution to control the final pH value to 8.0, and silica gel was prepared. (3) According to the element ratio of the target catalyst, measure the active component precursor mixture solution and silica gel. At 55°C, add the active component precursor mixture solution and 0.4M precipitant solution (sodium carbonate) to the silica gel in parallel flow, control the pH to 9, and obtain a mixed suspension. (4) According to the elemental ratio of the target catalyst, measure 3wt% of an aqueous solution of silicon nanotubes (length ~200nm, diameter ~10nm) and a mixed suspension. Under continuous stirring, add the aqueous solution of 3wt% silicon nanotubes to the mixed suspension. After aging at 80°C for 5 hours, load it into a reaction vessel and crystallize it at 180°C for 10 hours in a hydrothermal reactor to obtain the catalyst precursor. (5) The catalyst precursor was filtered and washed, the filtrate had a conductivity of 500 μS / cm, dried at 120°C for 13 hours, and then calcined in a muffle furnace at 550°C for 8 hours. The filtrate was then sheeted into 5.1 mm thick sheets. The copper-based catalyst B was prepared by cutting a sample from a depth of 5.0 mm.

[0026] Example 3 A catalyst was prepared with a composition of 45% copper oxide, 10% cerium oxide, 15% silicon nanotubes, and 30% silicon oxide.

[0027] (1) Weigh copper nitrate and cerium nitrate according to the element ratio of the target catalyst. Dissolve copper nitrate and cerium nitrate in deionized water at room temperature and stir evenly to obtain a mixed solution of active component precursors. Control the concentration of copper nitrate to 0.3M. (2) At 25°C, dilute hydrochloric acid aqueous solution was added to a 10wt% (calculated as silicon dioxide) sodium silicate aqueous solution to control the final pH value to 8.0, and silica gel was prepared. (3) According to the element ratio of the target catalyst, measure the active component precursor mixture solution and silica gel. At 60°C, add the active component precursor mixture solution and 0.4M composite precipitant solution (sodium carbonate and sodium bicarbonate mixture solution, mass ratio 15:1) to the silica gel in parallel flow, control the pH to 7, and obtain a mixed suspension. (4) According to the elemental ratio of the target catalyst, measure 4wt% of an aqueous solution of silicon nanotubes (length ~150nm, diameter ~5nm) and a mixed suspension. Under continuous stirring, add the 4wt% aqueous solution of silicon nanotubes to the mixed suspension. After aging at 75°C for 6 hours, load it into a reaction vessel and then crystallize it at 190°C for 12 hours in a hydrothermal reactor to obtain the catalyst precursor. (5) The catalyst precursor was filtered and washed, the filtrate had a conductivity of 500 μS / cm, dried at 130°C for 14 hours, and then calcined in a muffle furnace at 550°C for 7 hours. The filtrate was then sheeted into 5.1 mm thick sheets. The copper-based catalyst C was prepared by TEM (5.0 mm). Figure 1 The nanotube structure is clearly visible. This structure reduces the particle size of copper and improves the dispersion of active components through confinement, while also increasing the total specific surface area of ​​the catalyst and enriching hydrogen.

[0028] Example 4 A catalyst was prepared with a composition of 50% copper oxide, 15% cerium oxide, 5% silicon nanotubes, and 35% silicon oxide.

[0029] (1) Weigh copper nitrate and cerium nitrate according to the element ratio of the target catalyst. Dissolve copper nitrate and cerium nitrate in deionized water at room temperature and stir evenly to obtain a mixed solution of active component precursor. Control the concentration of copper nitrate to 0.4M. (2) At 30°C, dilute hydrochloric acid aqueous solution was added to 11wt% (calculated as silicon dioxide) sodium silicate aqueous solution to control the final pH value to 8.5 and prepare silica gel; (3) According to the element ratio of the target catalyst, measure the active component precursor mixture solution and silica gel. At 55°C, add the active component precursor mixture solution and 0.5M sodium carbonate precipitant solution to the silica gel in parallel flow, control the pH to 7.5, and obtain a mixed suspension. (4) According to the elemental ratio of the target catalyst, measure 5wt% of an aqueous solution of silicon nanotubes (length ~200nm, diameter ~4nm) and a mixed suspension. Under continuous stirring, add the 5wt% aqueous solution of silicon nanotubes to the mixed suspension. After aging at 75°C for 5.5 hours, load it into a reaction vessel and crystallize it at 190°C for 15 hours in a hydrothermal reactor to obtain the catalyst precursor. (5) The catalyst precursor was filtered and washed, the filtrate had a conductivity of 500 μS / cm, dried at 110°C for 13 hours, and then calcined in a muffle furnace at 450°C for 8 hours. The filtrate was then sheeted into 5.1 mm thick sheets. The copper-based catalyst D was prepared by cutting a sample from a depth of 5.0 mm.

[0030] Example 5 A catalyst was prepared with a composition of 40% copper oxide, 25% cerium oxide, 10% silicon nanotubes, and 30% silicon oxide.

[0031] (1) Weigh copper nitrate and cerium nitrate according to the element ratio of the target catalyst. Dissolve copper nitrate and cerium nitrate in deionized water at room temperature and stir evenly to obtain a mixed solution of active component precursors. Control the concentration of copper nitrate to 0.5M. (2) At 35°C, dilute hydrochloric acid aqueous solution was added to a 12wt% (calculated as silicon dioxide) sodium silicate aqueous solution to control the final pH value to 7.5, and silica gel was prepared. (3) According to the element ratio of the target catalyst, measure the active component precursor mixture solution and silica gel. At 60°C, add the active component precursor mixture solution and 0.5M precipitant solution (sodium carbonate and ammonium bicarbonate mixture solution, mass ratio 12:1) to the silica gel in parallel flow, control the pH to 8.5, and obtain a mixed suspension. (4) According to the elemental ratio of the target catalyst, measure 4wt% of an aqueous solution of silicon nanotubes (length ~250nm, diameter ~10nm) and a mixed suspension. Under continuous stirring, add the aqueous solution of silicon nanotubes to the mixed suspension. After aging at 80°C for 5 hours, load it into a reaction vessel and then crystallize it at 160°C for 20 hours in a hydrothermal reactor to obtain the catalyst precursor. (5) The catalyst precursor was filtered and washed, the filtrate had a conductivity of 500 μs / cm, dried at 130°C for 13 hours, and then calcined in a muffle furnace at 400°C for 8 hours. The filtrate was then sheeted into 5.1 mm thick sheets. The copper-based catalyst E was prepared by cutting a sample from a depth of 5.0 mm.

[0032] Example 6 A catalyst was prepared with a composition of 55% copper oxide, 15% cerium oxide, 5% silicon nanotubes, and 25% silicon oxide.

[0033] (1) Weigh copper nitrate and cerium nitrate according to the element ratio of the target catalyst. Dissolve copper nitrate and cerium nitrate in deionized water at room temperature and stir evenly to obtain a mixed solution of active component precursors. Control the concentration of copper nitrate to 0.5M. (2) At 40°C, dilute hydrochloric acid aqueous solution was added to a 10wt% (calculated as silicon dioxide) sodium silicate aqueous solution, and the final pH value was controlled to 8 to prepare silica gel; (3) According to the element ratio of the target catalyst, measure the active component precursor mixture solution and silica gel. At 65°C, add the active component precursor mixture solution and 0.3M precipitant solution (sodium carbonate and sodium bicarbonate mixture solution, mass ratio 10:1) to the silica gel in parallel flow, control the pH to 9, and obtain a mixed suspension. (4) According to the elemental ratio of the target catalyst, measure 5wt% of an aqueous solution of silicon nanotubes (length ~150nm, diameter ~3nm) and a mixed suspension. Under continuous stirring, add the aqueous solution of silicon nanotubes to the mixed suspension. After aging at 70°C for 1 hour, load it into a reaction vessel and crystallize it at 180°C for 20 hours in a hydrothermal reactor to obtain the catalyst precursor. (5) The catalyst precursor was filtered and washed, the filtrate had a conductivity of 500 μS / cm, dried at 120°C for 13 hours, and then calcined in a muffle furnace at 550°C for 8 hours. The filtrate was then sheeted into 5.1 mm thick sheets. The copper-based catalyst F was prepared by cutting a 5.0 mm sample.

[0034] Example 7 A catalyst was prepared with a composition of 50% copper oxide, 5% cerium oxide, 5% silicon nanotubes, and 40% silicon oxide.

[0035] (1) Weigh copper nitrate and cerium nitrate according to the element ratio of the target catalyst. Dissolve copper nitrate and cerium nitrate in deionized water at room temperature and stir evenly to obtain a mixed solution of active component precursor, wherein the concentration of copper nitrate is 0.4M. (2) At 25°C, an aqueous solution of acetic acid was added to an 11 wt% (calculated as silicon dioxide) sodium silicate aqueous solution, and the final pH value was controlled to 7.5 to prepare silica gel; (3) According to the element ratio of the target catalyst, measure the active component precursor mixture solution and silica gel. At 50°C, add the active component precursor mixture solution and 0.5M precipitant solution (sodium carbonate and ammonium bicarbonate mixture solution, mass ratio 7:1) to the silica gel in parallel flow, control the pH to 10, and obtain a mixed suspension. (4) According to the elemental ratio of the target catalyst, measure 3wt% of an aqueous solution of silicon nanotubes (length ~250nm, diameter ~10nm) and a mixed suspension. Under continuous stirring, add the aqueous solution of silicon nanotubes to the mixed suspension. After aging at 65°C for 5.5 hours, load it into a reaction vessel and then into a hydrothermal reactor at 200°C for 15 hours to obtain the catalyst precursor. (5) The catalyst precursor was filtered and washed, the filtrate had a conductivity of 500 μs / cm, dried at 90°C for 24 hours, and then calcined in a muffle furnace at 550°C for 8 hours. The filtrate was then sheeted into 5.1 mm sheets. The copper-based catalyst G was prepared by cutting a sample from a depth of 5.0 mm.

[0036] Example 8 A catalyst was prepared with a composition of 50% copper oxide, 20% cerium oxide, 15% silicon nanotubes, and 15% silicon oxide.

[0037] (1) Weigh copper nitrate and cerium nitrate according to the element ratio of the target catalyst. Dissolve copper nitrate and cerium nitrate in deionized water at room temperature and stir evenly to obtain a mixed solution of active component precursors. Control the concentration of copper nitrate to 0.5M. (2) At 30°C, an aqueous solution of acetic acid was added to a 12wt% (calculated as silica) sodium silicate aqueous solution, and the final pH value was controlled to 7.5 to prepare silica gel; (3) According to the element ratio of the target catalyst, measure the active component precursor mixture solution and silica gel. At 55°C, add the active component precursor mixture solution and 0.3M precipitant solution (sodium carbonate and ammonium bicarbonate mixture solution, mass ratio 8:1) to the silica gel in parallel flow, control the pH to 8.5, and obtain a mixed suspension. (4) According to the element ratio of the target catalyst, measure 6wt% aqueous solution of silicon nanotubes and mixed suspension. Under continuous stirring, add 6wt% aqueous solution of silicon nanotubes to mixed suspension. After aging at 70°C for 5 hours, load into reaction vessel. Then, load into hydrothermal reactor at 170°C for 24 hours to crystallize and obtain catalyst precursor. (5) The catalyst precursor was filtered and washed, the filtrate had a conductivity of 500 μs / cm, dried at 120°C for 36 hours, and then calcined in a muffle furnace at 350°C for 8 hours. The filtrate was then sheeted into 5.1 mm thick sheets. The copper-based catalyst H was prepared by cutting a sample from a depth of 5.0 mm.

[0038] Example 9 A catalyst was prepared with a composition of 30% copper oxide, 20% cerium oxide, 5% silicon nanotubes, and 45% silicon oxide.

[0039] (1) According to the element ratio of the target catalyst, weigh copper nitrate and cerium nitrate, dissolve copper nitrate and cerium nitrate in deionized water at 60°C, stir evenly to obtain a mixed solution of active component precursor, wherein the concentration of copper nitrate is 0.4M; (2) At 35°C, an aqueous solution of acetic acid was added to an 11 wt% (calculated as silica) sodium silicate aqueous solution, and the final pH value was controlled to 7.5 to prepare silica gel; (3) According to the element ratio of the target catalyst, measure the active component precursor mixture solution and silica gel. At 65°C, add the active component precursor mixture solution and 0.6M precipitant solution (sodium carbonate and ammonium bicarbonate mixture solution, mass ratio 9:1) to the silica gel in parallel flow, control the pH to 8, and obtain a mixed suspension. (4) According to the element ratio of the target catalyst, measure 6wt% aqueous solution of silicon nanotubes and mixed suspension. Under continuous stirring, add 6wt% aqueous solution of silicon nanotubes to mixed suspension. After aging at 85°C for 15 hours, load into the reaction vessel. Then, load into the hydrothermal reactor at 190°C for 20 hours to crystallize and obtain the catalyst precursor. (5) The catalyst precursor was filtered and washed, the filtrate had a conductivity of 500 μs / cm, dried at 120°C for 20 hours, and then calcined in a muffle furnace at 550°C for 8 hours. The filtrate was then sheeted into plates (Ø5.1 mm). The copper-based catalyst I was prepared by cutting a sample from a depth of 5.0 mm.

[0040] Comparative Example 1 A catalyst with a composition of 50% copper oxide, 5% silicon nanotubes, and 45% silicon oxide was prepared.

[0041] (1) At room temperature, copper nitrate was dissolved in deionized water and stirred until homogeneous to obtain a mixed solution of active component precursors, wherein the concentration of copper nitrate was 0.4 M; (2) At 25°C, dilute hydrochloric acid aqueous solution was added to a 12wt% (calculated as silicon dioxide) sodium silicate aqueous solution to control the final pH value to 7.5, and silica gel was prepared. (3) According to the element ratio of the target catalyst, measure the active component precursor mixture solution and silica gel. At 60°C, add the active component precursor mixture solution and 0.3M sodium carbonate precipitant solution to the silica gel in parallel flow, control the pH to 8, and obtain a mixed suspension. (4) According to the element ratio of the target catalyst, measure 3wt% aqueous solution of silicon nanotubes and mixed suspension. Under continuous stirring, add 3wt% aqueous solution of silicon nanotubes to mixed suspension. After aging at 75°C for 4 hours, load into reaction vessel. Then, crystallize at 160°C for 20 hours in a hydrothermal reactor to obtain catalyst precursor. (5) The catalyst precursor was filtered and washed, the filtrate had a conductivity of 500 μS / cm, dried at 110°C for 12 hours, and then calcined in a muffle furnace at 550°C for 7 hours. The filtrate was then sheeted into 5.1 mm sheets. The copper-based catalyst J was prepared by cutting a sample from a depth of 5.0 mm.

[0042] Comparative Example 2 A catalyst with a composition of 40% copper oxide, 15% cerium oxide, and 45% silicon oxide was prepared.

[0043] (1) Weigh copper nitrate and cerium nitrate according to the element ratio of the target catalyst. Dissolve copper nitrate and cerium nitrate in deionized water at room temperature and stir evenly to obtain a mixed solution of active component precursor, wherein the concentration of copper nitrate is 0.4M. (2) At 30°C, add acetic acid aqueous solution to 12wt% (calculated as silicon dioxide) sodium silicate aqueous solution, control the final pH value to 8, and prepare silica gel; (3) According to the element ratio of the target catalyst, measure the active component precursor mixture solution and silica gel. At 60°C, add the active component precursor mixture solution and 0.4M sodium carbonate precipitant solution in parallel to the silica gel, control the pH to 9, and obtain a mixed suspension. (4) After aging the mixed suspension at 80°C for 5 hours, it was loaded into a reaction vessel and crystallized at 150°C for 24 hours in a hydrothermal reactor to obtain the catalyst precursor. (5) The catalyst precursor was filtered and washed, the filtrate had a conductivity of 500 μS / cm, dried at 120°C for 13 hours, and then calcined in a muffle furnace at 550°C for 7 hours. The filtrate was then sheeted into plates (Ø5.1 mm). The copper-based catalyst K was prepared by cutting a 5.0 mm sample.

[0044] Comparative Example 3 A catalyst was prepared with a composition of 35% copper oxide, 20% cerium oxide, 5% silicon nanotubes, and 40% silicon oxide.

[0045] (1) Weigh copper nitrate and cerium nitrate according to the element ratio of the target catalyst. Dissolve copper nitrate and cerium nitrate in deionized water at room temperature and stir evenly to obtain a mixed solution of active component precursor, wherein the concentration of copper nitrate is 0.5M. (2) Prepare a 10 wt% (based on silica) sodium silicate aqueous solution at room temperature; (3) According to the element ratio of the target catalyst, measure the active component precursor mixed solution and sodium silicate solution, and add the active component precursor mixed solution and 0.4M precipitant sodium carbonate solution in parallel to the sodium silicate solution at 50°C, control the pH to 7.5, and obtain a mixed suspension. (4) Under continuous stirring, 2wt% aqueous solution of silicon nanotubes was added to the mixed suspension and aged at 75°C for 4.5 hours to obtain the catalyst precursor; (5) The catalyst precursor was filtered and washed, the filtrate had a conductivity of 500 μS / cm, dried at 110°C for 12 hours, and then calcined in a muffle furnace at 550°C for 7 hours. The filtrate was then sheeted into 5.1 mm sheets. The copper-based catalyst L was prepared by cutting a sample from a depth of 5.0 mm.

[0046] Comparative Example 4 A catalyst with a composition of 40% copper oxide, 15% cerium oxide, and 45% silicon oxide was prepared.

[0047] (1) Weigh copper nitrate and cerium nitrate according to the element ratio of the target catalyst. Dissolve copper nitrate and cerium nitrate in deionized water at 40°C and stir evenly to obtain a mixed solution of active component precursor. Control the concentration of copper nitrate to 0.4M. (2) A commercially available aqueous solution of nano-silica (10 wt%) was mixed with the silica gel prepared in Comparative Example 1 to obtain a mixture of nano-silica and silica gel in a mass ratio of 2:1. (3) According to the element ratio of the target catalyst, measure the active component precursor mixture solution and the silica gel mixture. At 60°C, react the active component precursor mixture solution with the mixed precipitant solution (sodium carbonate and sodium bicarbonate, mass ratio 8:1) in parallel flow. Then add it to the silica gel mixture and control the pH to 8 to obtain a mixed suspension. (4) According to the element ratio of the target catalyst, measure 5wt% of an aqueous solution of silicon nanotubes (length ~200nm, diameter ~4nm), add the aqueous solution of silicon nanotubes to the mixed suspension under continuous stirring, age at 75°C for 4 hours, and crystallize at 180°C for 24 hours in a reactor to obtain the catalyst precursor. (5) The catalyst precursor was filtered and washed, the filtrate had a conductivity of 500 μS / cm, dried at 110°C for 13 hours, and then calcined in a muffle furnace at 550°C for 7 hours. The filtrate was then sheeted into plates (Ø5.1 mm). The copper-based catalyst M was prepared by cutting a 5.0 mm sample.

[0048] Comparative Example 5 A catalyst with a composition of 45% copper oxide, 15% cerium oxide, and 40% silicon oxide was prepared.

[0049] (1) According to the element ratio of the target catalyst, weigh copper nitrate and cerium nitrate, dissolve copper nitrate and cerium nitrate in deionized water at 60°C, stir evenly to obtain a mixed solution of active component precursor, wherein the concentration of copper nitrate is 0.5M; (2) Add nano-silica to a 10wt% (calculated as silica) sodium silicate aqueous solution to prepare a mixed suspension of nano-silica and sodium silicate; (3) According to the element ratio of the target catalyst, measure the active component precursor mixed solution and the mixed suspension. At 60°C, add the active component precursor mixed solution and 0.4M sodium carbonate precipitant solution in parallel to the above mixed suspension, control the pH to 9, and obtain the mixed precursor suspension. (4) After aging the mixed precursor suspension at 75°C for 4 hours, it was loaded into a reaction vessel and crystallized at 190°C for 20 hours in a hydrothermal reactor to obtain the catalyst precursor. (5) The catalyst precursor was filtered and washed, the filtrate had a conductivity of 500 μS / cm, dried at 130°C for 11 hours, and then calcined in a muffle furnace at 550°C for 6.5 hours. The filtrate was then sheeted into plates (Ø5.1 mm). The copper-based catalyst N was prepared by cutting a sample from a depth of 5.0 mm.

[0050] The evaluation criteria were standardized as follows: a microreactor hydrogenation reactor was used to evaluate catalyst lifetime. After the catalyst was crushed to 40-60 mesh, the hydrogenation reaction was carried out in a 10mm inner diameter stainless steel tube reactor. Before the reaction, the catalyst was reduced for 10 hours at 300℃ with a N2+H2 mixture containing 10 vol% H2, and then switched to hydrogen for the reaction. The operating conditions were: reaction pressure 4.0 MPa, reaction temperature 95℃, and liquid hourly space velocity 1 h⁻¹. -1 The hydrogen-aldehyde ratio was 2, the concentration of hydroxypentanal was 10 wt%, water was 2 wt%, ethanol was 87 wt%, and the remainder consisted of isobutyraldehyde, formaldehyde, 1115 ester, etc. The hydrogenation results are shown in Table 1.

[0051] Table 1 Catalyst Evaluation Results Data Table

[0052] Table 2 Stability data for catalyst A

[0053] The above activity evaluation results show that adding cerium promoter and silicon nanotubes to copper-based catalysts can significantly improve catalyst reaction performance. The introduction of cerium enhances the interaction between the active component and the support, improving catalyst stability, while also introducing oxygen vacancies to stabilize and regulate the distribution of reduced copper on the catalyst surface, further enhancing catalyst stability. Even after 1200 hours of operation, it still maintains good catalytic performance. The introduction of high specific surface area silicon nanotubes improves the dispersion of the active component, and the hydrogen enrichment effect of the nanotube channels reduces the hydrogen-aldehyde ratio. Combined with the comparative examples, it can be seen that the introduction of ordinary nano-silica cannot achieve this effect.

[0054] The above description of the disclosed embodiments enables those skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A copper-based catalyst for the hydrogenation preparation of neopentyl glycol, characterized in that, The copper-based catalyst is an oxygen vacancy-stabilized silicon nanotube modified highly dispersed supported copper-silicon catalyst. By weight percentage, the copper-based catalyst consists of 20% to 55% copper oxide, 5% to 25% cerium oxide, 1% to 15% silicon nanotubes, and 10% to 50% silicon oxide.

2. The copper-based catalyst for the hydrogenation preparation of neopentyl glycol according to claim 1, characterized in that, The copper-based catalyst comprises, by weight percentage, 30% to 50% copper oxide, 10% to 25% cerium oxide, 5% to 15% silicon nanotubes, and 15% to 40% silicon oxide.

3. A method for preparing a copper-based catalyst as described in any one of claims 1 or 2, characterized in that, Includes the following steps: (1) Weigh copper nitrate and cerium nitrate according to the element ratio of the target catalyst. Dissolve copper nitrate and cerium nitrate in deionized water at room temperature and stir evenly to obtain a mixed solution of active component precursors. (2) At 20~60℃, add an acidic aqueous solution to the sodium silicate aqueous solution and control the final pH value to 7.0~8.5 to prepare silica gel; (3) According to the element ratio of the target catalyst, measure the active component precursor mixture solution and silica gel, and add the active component precursor mixture solution and precipitant solution to the silica gel in parallel at 40~85℃, control the pH to 6~10, and obtain a mixed suspension. (4) According to the element ratio of the target catalyst, measure the aqueous solution of silicon nanotubes and the mixed suspension, add the aqueous solution of silicon nanotubes to the mixed suspension under continuous stirring, age and then load it into the reaction vessel for hydrothermal crystallization to obtain the catalyst precursor. (5) The catalyst precursor is filtered, washed, dried, calcined and shaped to obtain the copper-based catalyst.

4. The preparation method according to claim 3, characterized in that, The copper salt and cerium salt mentioned in step (1) are selected from one or more of nitrates, sulfates, chlorides, acetates, oxalates and bromides; The concentration of copper salt in the active component precursor mixture solution is 0.1~0.8M.

5. The preparation method according to claim 3, characterized in that, The acidic aqueous solution mentioned in step (2) is one of hydrochloric acid, sulfuric acid, or acetic acid aqueous solution; The sodium silicate aqueous solution contains 7-12 wt% silica.

6. The preparation method according to claim 3, characterized in that, The precipitant mentioned in step (3) is one or more of sodium carbonate, potassium carbonate, sodium bicarbonate, ammonia, ammonium bicarbonate and sodium hydroxide; The concentration of the precipitant solution is 0.2~1.5M.

7. The preparation method according to claim 3, characterized in that, The concentration of silicon nanotubes in the aqueous solution of silicon nanotubes in step (4) is 1~10wt%; the length of the silicon nanotubes is 10~250nm and the diameter is 1~10nm. The aging temperature is 60~80℃; the aging time is 1~8h; The hydrothermal crystallization temperature is 100~200℃; the time is 4~24h.

8. The preparation method according to claim 3, characterized in that, The drying temperature in step (5) is 90~130℃ and the time is 12~36 hours; the calcination temperature is 350~650℃ and the time is 2~8 hours.

9. The use of a copper-based catalyst as described in any one of claims 1 or 2, or a copper-based catalyst prepared by the method described in any one of claims 3 to 8, in the preparation of neopentyl glycol, characterized in that, The copper-based catalyst needs to be activated before use. The activation temperature is 250~350℃, the activation atmosphere is H2, or a mixture of H2 and N2, Ar, He inert gases, wherein the volume percentage of hydrogen is 5~80%, and the activation time is 10~20h.

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