A hydrogenation catalyst, its preparation method and application

Abstract

The hydrogenation catalyst provided by the present invention comprises: an active component Ag-Pd, an In2O3 auxiliary agent and a carrier. The present invention adopts Ag-Pd as the active component of the catalyst by designing the active component of the catalyst and the carrier structure, thereby ensuring good selectivity of the catalyst, improving the low-temperature activity of the catalyst, suppressing the sintering rate of the catalyst under high temperature conditions, and improving the service life of the catalyst. By adding the In2O3 auxiliary agent, the agglomeration of Ag on the catalyst surface is effectively suppressed, further improving the stability and selectivity of the catalyst. In addition, the catalyst preparation process is simple and friendly, the production process is highly safe, and is suitable for industrial production.

Description

Technical Field

[0001] The present invention relates to the technical field of catalysts, and in particular to a hydrogenation catalyst and a preparation method and application thereof. Background Art

[0002] In the past few decades, synthetic plastics have been widely used due to their low cost, high durability and strong processability. However, the increase in plastic applications has also brought troubles to the environment. Many plastic products (especially packaging and disposable items) become waste after use. However, only 18% of these plastic wastes are recycled, and even less are incinerated or landfilled. Most of the remaining plastic waste is discarded in the environment.

[0003] The environmental crisis caused by plastic pollution has increased people's demand for alternative environmentally friendly materials. In recent years, people have focused on biodegradable plastics. At present, many countries around the world have formulated many regulations to limit the use of traditional plastics and promote the development of biodegradable plastics industry. At the same time, biodegradable plastics have also been widely studied, and many of them have reached industrial scale, such as polylactic acid (PLA), polybutylene succinate (PBS), polycaprolactone (PCL), etc., and are widely used in agriculture, forestry, packaging and other disposable products. PGA (polyglycolic acid) is the simplest linear degradable polyester with excellent mechanical properties, barrier properties, degradability and biocompatibility, and is receiving more and more attention. Methyl glycolate (MG) is a major synthetic raw material for PGA. With the overcapacity of coal-to-ethylene glycol in my country, the preparation of MG by selective catalytic hydrogenation of dimethyl oxalate (DMO) from coal-based synthesis gas has attracted more and more attention from scientific research institutes and enterprises.

[0004] At present, the hydrogenation of dimethyl oxalate to methyl glycolate mainly uses Cu-based and Ag-based hydrogenation catalysts. Studies have shown that Cu-based catalysts are easy to catalyze the deep hydrogenation of MG to produce ethylene glycol, and the yield of methyl glycolate is generally low. Ag-based catalysts can highly selectively obtain methyl glycolate for the hydrogenation of dimethyl oxalate, but Ag-based hydrogenation catalysts have low low-temperature activity, high initial reaction temperature, and are easy to sinter, resulting in a decrease in the conversion rate of dimethyl oxalate, which is not conducive to the industrial production of catalysts. Summary of the invention

[0005] In view of this, the technical problem to be solved by the present invention is to provide a hydrogenation catalyst and a preparation method and application thereof, wherein the prepared catalyst has a high conversion rate and selectivity.

[0006] To achieve the above object, the present invention provides a hydrogenation catalyst, comprising: an active component Ag-Pd, an In2O3 auxiliary agent and a carrier.

[0007] The Ag-Pd catalyst provided by the present invention contains an In2O3 auxiliary agent, thereby improving the conversion rate of dimethyl oxalate and the selectivity of methyl glycolate.

[0008] Optionally, the mass percentage of the active component Ag in the catalyst is 0.01% to 18%, more preferably 1% to 15%.

[0009] Optionally, the mass percentage of the active component Pd in ​​the catalyst is 0.01% to 3%, more preferably 0.05% to 1%.

[0010] Optionally, the mass percentage of the In2O3 additive in the catalyst is 0.01% to 5%, more preferably 0.1% to 3%.

[0011] Optionally, the mass percentage of the carrier to the catalyst is 74% to 99.97%.

[0012] Optionally, the specific surface area of ​​the carrier is 150-600m 2 / g.

[0013] Optionally, the specific surface area of ​​the catalyst is 150-600m 2 / g.

[0014] Optionally, the carrier is selected from SiO2.

[0015] In the present invention, the total content of the active components Ag-Pd, In2O3 auxiliary agent and carrier meets 100%.

[0016] The present invention provides a method for preparing the above hydrogenation catalyst, comprising the following steps:

[0017] S1) preparing a metal salt solution A, wherein the metal salt solution A contains silver ions, palladium ions and indium ions;

[0018] Prepare carrier solution B;

[0019] Prepare precipitant solution C;

[0020] S2) mixing solution A, solution B and solution C to perform precipitation reaction to obtain a catalyst precursor slurry;

[0021] S3) the catalyst precursor slurry is aged, washed, dried and calcined to obtain a hydrogenation catalyst;

[0022] Or S3') the catalyst precursor slurry is evaporated by jet instantaneous pyrolysis, and then the evaporated material is subjected to hot air microspheroidization treatment to obtain a hydrogenation catalyst.

[0023] Optionally, the compound providing the silver ions is selected from silver nitrate or silver acetate.

[0024] Optionally, the compound providing the palladium ions is selected from palladium chloride, palladium nitrate or palladium acetate.

[0025] Optionally, the compound providing the indium ions is selected from indium nitrate.

[0026] Optionally, in the metal salt solution A, the concentration of silver ions is 0.01 to 5 mol / L, the concentration of palladium ions is 0.01 to 5 mol / L, and the concentration of indium ions is 0.01 to 2 mol / L.

[0027] Optionally, the carrier solution B is selected from a solution of silica sol, white carbon black or water glass.

[0028] Optionally, in the carrier solution B, the mass concentration of the carrier is 5 to 30%.

[0029] Optionally, the precipitant is selected from sodium carbonate, sodium hydroxide, ammonium carbonate, ammonium bicarbonate, sodium bicarbonate, ammonia water or urea.

[0030] Optionally, in the precipitant solution, the mass concentration of the precipitant is 5% to 40%.

[0031] Optionally, the solvent of the above solution A, solution B and solution C is water.

[0032] Optionally, the volume ratio of the metal salt solution A, the carrier solution B, and the precipitant solution C is 1:(2-10):(0.5-2).

[0033] Optionally, an acidic substance or an alkaline substance is used to adjust the pH value of the carrier solution B to 3-6.

[0034] Optionally, the acidic substance may be a conventional acidic substance in the art, including but not limited to nitric acid, sulfuric acid, acetic acid or hydrochloric acid.

[0035] Optionally, the alkaline substance may be a conventional alkaline substance in the art, including but not limited to sodium carbonate, sodium hydroxide, ammonium carbonate, ammonium bicarbonate, sodium bicarbonate or an aqueous ammonia solution.

[0036] Optionally, the precipitation reaction temperature is 20-95°C.

[0037] Optionally, the aging temperature is 40 to 95° C., and the aging time is 0.5 to 12 hours.

[0038] Optionally, the drying temperature is 80 to 150° C., and the drying time is 2 to 24 hours.

[0039] Optionally, the calcination temperature is 300 to 800° C., and the calcination time is 0.5 to 12 hours.

[0040] Optionally, when preparing an industrial-grade granular catalyst, a granulation operation is further included between the drying and calcining.

[0041] Optionally, when preparing an industrial-grade particle catalyst, a shaping operation is further included after the calcination.

[0042] Optionally, the inlet air temperature of the jet instantaneous pyrolysis method is 80-250° C., more preferably 100-200° C. In some specific embodiments of the present invention, the inlet air temperature is 120° C., 180° C., or an interval with any of the above values ​​as the upper or lower limit.

[0043] Optionally, the injection pressure of the injection instantaneous pyrolysis method is 0.1 to 60 bar, more preferably 0.5 to 20 bar. In some specific embodiments of the present invention, the injection pressure is 2 bar, 3 bar, or an interval with any of the above values ​​as the upper or lower limit.

[0044] Optionally, a device with a spray or centrifugal drying function is used for jet instantaneous pyrolysis. The catalyst precursor slurry is pumped to the atomizer. The atomizer evenly atomizes the liquid into ultra-micron droplets and enters the tower. The air enters the heating system, is heated to the temperature required for the process, and pyrolyzes into the required material after contacting the droplets.

[0045] After the jet instant pyrolysis, the material is subjected to hot air microspheroidization.

[0046] The temperature of the hot air microspheroidization treatment is 80-150° C., more preferably 80-100° C. In some specific embodiments of the present invention, the temperature is 80° C., 90° C., or an interval with any of the above values ​​as the upper or lower limit.

[0047] Optionally, the hot air microspheroidization treatment time is 1 to 30 min, more preferably 5 to 15 min. In some specific embodiments of the present invention, the time is 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15 min, or an interval with any of the above values ​​as the upper or lower limit.

[0048] Under the control of the temperature and time parameters of the hot air microspheroidization treatment, the particle size of the microspheres after treatment is 0.075-1 mm.

[0049] The hot air microspheroidization treatment described in the present invention is to put the powder material with small particle size obtained by the jet instantaneous pyrolysis method into a high temperature resistant container, and blow the hot air heated by the electric heating wire into it from one side of the beaker. The powder with small particle size collides and adheres to each other in the hot air, and finally the powder is processed into fine particles with larger particle size and higher strength.

[0050] Optionally, the high temperature resistant container is a hard glass container.

[0051] Optionally, the hot air microspheroidization treatment further includes calcination.

[0052] Optionally, the calcination temperature is 300-650°C, more preferably 300-600°C.

[0053] The calcination time is 0.5 to 12 hours, more preferably 1 to 6 hours.

[0054] Optionally, when preparing industrial-grade granular catalysts, the hot air microspheroidization treatment further includes dry or wet granulation, calcination and molding.

[0055] In the process of preparing the above-mentioned hydrogenation catalyst, the present invention adopts a combination of jet instantaneous pyrolysis and microspheroidization treatment to obtain a catalyst with highly dispersed active components. On the basis of higher selectivity, the low-temperature high activity of the catalyst is further effectively improved, and the prepared catalyst has excellent catalytic performance and stability.

[0056] The present invention provides application of the hydrogenation catalyst or the hydrogenation catalyst prepared by the preparation method as a catalyst for the reaction of preparing methyl glycolate by hydrogenating oxalate.

[0057] The invention provides a gas phase hydrogenation reaction for preparing methyl glycolate from oxalate, and adopts the hydrogenation catalyst prepared by the preparation method or the hydrogenation catalyst as a catalyst.

[0058] Compared with the prior art, the hydrogenation catalyst provided by the present invention comprises: an active component Ag-Pd, an In2O3 auxiliary agent and a carrier.

[0059] The present invention adopts Ag-Pd as the catalyst active component by designing the catalyst active component and the carrier structure, thereby ensuring good selectivity of the catalyst, improving the low-temperature activity of the catalyst, inhibiting the catalyst sintering speed under high temperature conditions, and improving the service life of the catalyst. By adding the In2O3 auxiliary agent, the agglomeration of Ag on the catalyst surface is effectively inhibited, further improving the stability and selectivity of the catalyst. In addition, the catalyst preparation process is simple and friendly, the production process is highly safe, and is suitable for industrial production. DETAILED DESCRIPTION

[0060] In order to further illustrate the present invention, the hydrogenation catalyst provided by the present invention and its preparation method and application are described in detail below in conjunction with embodiments.

[0061] Example 1

[0062] 3.9g of silver nitrate, 0.13g of palladium acetate and 0.5g of indium nitrate hydrate were placed in a beaker, and 100g of distilled water was added to completely dissolve them, which was recorded as solution A; 200g of silica sol was weighed, 100g of distilled water was added and stirred evenly, and then concentrated nitric acid was slowly dripped into it with a dropper to adjust the pH value to 4, which was recorded as solution B; 10g of urea was placed in another beaker, 150g of distilled water was added to completely dissolve it, which was recorded as solution C; solution A, solution B and solution C were added into a container for precipitation reaction, and the temperature was maintained at 90°C; after the precipitation was completed, the temperature was maintained at 90°C and aged for 4 hours. The obtained catalyst precursor slurry was washed and filtered, dried at 120°C for 12 hours, and calcined at 450°C for 6 hours to obtain the target product catalyst.

[0063] Its specific surface area is 350m 2 / g.

[0064] The catalyst prepared above was made into 20-30 mesh size particles, loaded into a tubular reactor with a diameter of 12 mm, and activated for 8 hours in a hydrogen atmosphere at 250°C. Using dimethyl oxalate methanol solution as raw material, the reaction temperature was 180°C, and the liquid hourly space velocity was 0.4h -1 , hydrogen-ester ratio 50:1, reaction pressure 2MPa, reaction results are shown in Table 1.

[0065] Example 2

[0066] 7.9 g of silver nitrate, 0.19 g of palladium nitrate and 2.2 g of indium nitrate hydrate were placed in a beaker, and 100 g of distilled water was added to completely dissolve them, which was recorded as solution A. 45 g of white carbon black (BET specific surface area 200 m 2 / g), add 500g of distilled water and stir evenly, then slowly drop concentrated nitric acid with a dropper to adjust the pH value to 4, recorded as solution B; put 30g of sodium carbonate in another beaker, add 100g of distilled water to completely dissolve it, recorded as solution C; add solution A, solution B and solution C into a container for precipitation reaction, and keep the temperature at 40°C; after the precipitation is completed, keep the temperature at 40°C and age for 4 hours. The obtained catalyst precursor slurry is washed and filtered, dried at 120°C for 12 hours, and calcined at 600°C for 4 hours to obtain the target product catalyst.

[0067] Its specific surface area is 195m 2 / g.

[0068] The catalyst prepared above was made into 20-30 mesh size particles, loaded into a tubular reactor with a diameter of 12 mm, and activated for 4 hours in a hydrogen atmosphere at 280°C. Using dimethyl oxalate methanol solution as raw material, the reaction temperature was 180°C, and the liquid hourly space velocity was 0.4h -1 , hydrogen-ester ratio 50:1, reaction pressure 2MPa, reaction results are shown in Table 1.

[0069] Example 3

[0070] 14.2 g of silver nitrate, 0.06 g of palladium chloride and 1.1 g of indium nitrate hydrate were placed in a beaker, and 100 g of distilled water was added to completely dissolve them, which was recorded as solution A. 40 g of white carbon black (BET specific surface area 200 m 2 / g), add 500g of distilled water and stir evenly, then slowly drop concentrated nitric acid with a dropper to adjust the pH value to 4, recorded as solution B; put 30g of sodium carbonate in another beaker, add 100g of distilled water to completely dissolve it, recorded as solution C; add solution A, solution B and solution C into a container for precipitation reaction, and keep the temperature at 40°C; after the precipitation is completed, keep the temperature at 60°C and age for 4 hours. The obtained catalyst precursor slurry is washed and filtered, dried at 100°C for 12 hours, and calcined at 600°C for 4 hours to obtain the target product catalyst.

[0071] Its specific surface area is 170m 2 / g.

[0072] The catalyst prepared above was made into 20-30 mesh size particles, loaded into a tubular reactor with a diameter of 12 mm, and activated for 4 hours in a hydrogen atmosphere at 300°C. Dimethyl oxalate methanol solution was used as the raw material, the reaction temperature was 180°C, and the liquid hourly space velocity was 0.4 h -1 , hydrogen-ester ratio 50:1, reaction pressure 2MPa, reaction results are shown in Table 1.

[0073] Example 4

[0074] 0.4 g of silver acetate, 1.27 g of palladium nitrate and 0.5 g of indium nitrate hydrate were placed in a beaker, and 100 g of distilled water was added to completely dissolve them, which was recorded as solution A. 50 g of white carbon black (BET specific surface area 380 m 2 / g), add 500g of distilled water and stir evenly, then slowly drop concentrated nitric acid with a dropper to adjust the pH value to 4, recorded as solution B; put 5g of sodium carbonate in another beaker, add 100g of distilled water to dissolve it completely, recorded as solution C; add solution A, solution B and solution C into the container for precipitation reaction, and keep the temperature at 40°C; then after the precipitation is completed, keep the temperature at 60°C and age for 4 hours, the obtained catalyst precursor slurry is washed and filtered, dried at 90°C for 12 hours, and calcined at 400°C for 4 hours to obtain the target product catalyst.

[0075] Its specific surface area is 240m 2 / g.

[0076] The catalyst prepared above was made into 20-30 mesh size particles, loaded into a tubular reactor with a diameter of 12 mm, and activated for 6 hours under a hydrogen atmosphere at 200°C. Using dimethyl oxalate methanol solution as raw material, the reaction temperature was 180°C, and the liquid hourly space velocity was 0.4 h -1 , hydrogen-ester ratio 50:1, reaction pressure 2MPa, reaction results are shown in Table 1.

[0077] Example 5

[0078] 0.8g of silver nitrate, 0.63g of palladium chloride and 0.9g of indium nitrate hydrate were placed in a beaker, and 100g of distilled water was added to completely dissolve them, which was recorded as solution A; 120g of water glass was weighed, 500g of distilled water was added and stirred evenly, and then concentrated nitric acid was slowly dripped into it with a dropper to adjust the pH value to 5, which was recorded as solution B; 10g of sodium carbonate was placed in another beaker, 100g of distilled water was added to completely dissolve it, which was recorded as solution C; solution A, solution B and solution C were added into a container for precipitation reaction, and the temperature was maintained at 40°C; after the precipitation was completed, the temperature was maintained at 60°C and aged for 4 hours. The obtained catalyst precursor slurry was washed and filtered, dried at 120°C for 12 hours, and calcined at 500°C for 4 hours to obtain the target product catalyst.

[0079] Its specific surface area is 480m 2 / g.

[0080] The catalyst prepared above was made into 20-30 mesh size particles, loaded into a tubular reactor with a diameter of 12 mm, and activated for 4 hours in a hydrogen atmosphere at 250°C. Using dimethyl oxalate methanol solution as raw material, the reaction temperature was 180°C, and the liquid hourly space velocity was 0.4 h -1 , hydrogen-ester ratio 50:1, reaction pressure 2MPa, reaction results are shown in Table 1.

[0081] Example 6

[0082] 11.8 g of silver nitrate, 0.13 g of palladium acetate and 4.3 g of indium nitrate hydrate were placed in a beaker, and 100 g of distilled water was added to completely dissolve them, which was recorded as solution A. 45 g of white carbon black (BET specific surface area 380 m 2 / g), add 500g of distilled water and stir evenly, then slowly drop concentrated nitric acid with a dropper to adjust the pH value to 4, recorded as solution B; put 30g of sodium carbonate in another beaker, add 100g of distilled water to completely dissolve it, recorded as solution C; add solution A, solution B and solution C into a container for precipitation reaction, and keep the temperature at 40°C; after the precipitation is completed, keep the temperature at 60°C and age for 4 hours. The obtained catalyst precursor slurry is washed and filtered, dried at 120°C for 12 hours, and calcined at 600°C for 4 hours to obtain the target product catalyst.

[0083] Its specific surface area is 280m 2 / g.

[0084] The catalyst prepared above was made into 20-30 mesh size particles, loaded into a tubular reactor with a diameter of 12 mm, and activated for 4 hours in a hydrogen atmosphere at 250°C. Using dimethyl oxalate methanol solution as raw material, the reaction temperature was 180°C, and the liquid hourly space velocity was 0.4 h -1 , hydrogen-ester ratio 50:1, reaction pressure 2MPa, reaction results are shown in Table 1.

[0085] Example 7

[0086] 3.9 g of silver nitrate, 0.5 g of palladium nitrate and 0.5 g of indium nitrate hydrate were placed in a beaker, and 100 g of distilled water was added to completely dissolve them, which was recorded as solution A. 50 g of white carbon black (BET specific surface area 200 m 2 / g), add 500g of distilled water and stir evenly, then slowly drop concentrated nitric acid with a dropper to adjust the pH value to 4, recorded as solution B; put 15g of sodium carbonate in another beaker and add 150g of distilled water to completely dissolve it, recorded as solution C; add solution A, solution B and solution C into a container for precipitation reaction, and keep the temperature at 40°C; after the precipitation is completed, keep the temperature at 60°C and age for 4 hours. The obtained catalyst precursor slurry is washed and filtered, dried at 120°C for 8 hours, and calcined at 500°C for 4 hours to obtain the target product catalyst.

[0087] Its specific surface area is 190m 2 / g.

[0088] The catalyst prepared above was made into 20-30 mesh size particles, loaded into a tubular reactor with a diameter of 12 mm, and activated for 4 hours in a hydrogen atmosphere at 230°C. Using dimethyl oxalate methanol solution as raw material, the reaction temperature was 180°C, and the liquid hourly space velocity was 0.4 h -1 , hydrogen-ester ratio 50:1, reaction pressure 2MPa, reaction results are shown in Table 1.

[0089] Example 8

[0090] 2.4 g of silver nitrate, 0.4 g of palladium nitrate and 0.3 g of indium nitrate hydrate were placed in a beaker, and 120 g of distilled water was added to completely dissolve them, which was recorded as solution A. 48 g of white carbon black (BET specific surface area 380 m 2 / g), add 500g of distilled water and stir evenly, then slowly drop concentrated nitric acid with a dropper, recorded as solution B; put 12g of sodium carbonate in another beaker, add 120g of distilled water to completely dissolve it, adjust the pH value to 5, recorded as solution C; keep the temperature at 60°C, slowly drop solution C into the mixed solution of solution A and solution B, and the obtained catalyst precursor slurry is evaporated by jet pyrolysis, the spray inlet temperature is 180°C, and the spray pressure is 2bar; then the material is subjected to hot air microspheroidization treatment, the hot air temperature is 90°C, the treatment time is 14min, and the particle size of the treated main particles is 0.08-0.10mm; calcined at 500°C for 4 hours to obtain the target product catalyst.

[0091] Its specific surface area is 240m 2 / g.

[0092] The catalyst prepared above was made into 20-30 mesh size particles, loaded into a tubular reactor with a diameter of 12 mm, and activated for 4 hours in a hydrogen atmosphere at 230°C. Using dimethyl oxalate methanol solution as raw material, the reaction temperature was 180°C, and the liquid hourly space velocity was 0.4 h -1 , hydrogen-ester ratio 50:1, reaction pressure 2MPa, reaction results are shown in Table 1.

[0093] Example 9

[0094] 2.4 g of silver nitrate, 0.25 g of palladium nitrate and 0.2 g of indium nitrate hydrate were placed in a beaker, and 80 g of distilled water was added to completely dissolve them, which was recorded as solution A. 48 g of white carbon black (BET specific surface area 380 m 2 / g), add 500g of distilled water and stir evenly, then slowly drop concentrated nitric acid with a dropper to adjust the pH value to 4, recorded as solution B; put 8g of sodium carbonate in another beaker and add 80g of distilled water to completely dissolve it, recorded as solution C; keep the temperature at 70°C, slowly drop solution C into the mixed solution of solution A and solution B, and the obtained catalyst precursor slurry is evaporated by jet pyrolysis, the spray inlet temperature is 120°C, and the spray pressure is 3bar; then the material is subjected to hot air microspheroidization treatment, the hot air temperature is 80°C, the treatment time is 15min, and the particle size of the main particles after treatment is 0.08-0.10mm; calcined at 450°C for 4 hours to obtain the target product catalyst.

[0095] Its specific surface area is 260m 2 / g.

[0096] The catalyst prepared above was made into 20-30 mesh size particles, loaded into a tubular reactor with a diameter of 12 mm, and activated for 4 hours in a hydrogen atmosphere at 230°C. Using dimethyl oxalate methanol solution as raw material, the reaction temperature was 180°C, and the liquid hourly space velocity was 0.4 h -1, hydrogen-ester ratio 50:1, reaction pressure 2MPa, reaction results are shown in Table 1.

[0097] Example 10

[0098] 3.9 g of silver nitrate, 0.25 g of palladium nitrate and 0.5 g of indium nitrate hydrate were placed in a beaker, and 100 g of distilled water was added to completely dissolve them, which was recorded as solution A. 50 g of white carbon black (BET specific surface area 200 m 2 / g), add 500g of distilled water and stir evenly, then slowly drop concentrated nitric acid with a dropper to adjust the pH value to 4, recorded as solution B; put 15g of sodium carbonate in another beaker and add 150g of distilled water to completely dissolve it, recorded as solution C; add solution A, solution B and solution C into a container for precipitation reaction, and keep the temperature at 70°C; after the precipitation is completed, keep the temperature at 70°C and age for 8 hours. The obtained catalyst precursor slurry is washed and filtered, dried at 90°C for 16 hours, and calcined at 500°C for 4 hours to obtain the target product catalyst.

[0099] Its specific surface area is 180m 2 / g.

[0100] The catalyst prepared above was made into 20-30 mesh size particles, loaded into a tubular reactor with a diameter of 12 mm, and activated for 4 hours in a hydrogen atmosphere at 260°C. Using dimethyl oxalate methanol solution as raw material, the reaction temperature was 180°C, and the liquid hourly space velocity was 0.4 h -1 , hydrogen-ester ratio 50:1, reaction pressure 2MPa, reaction results are shown in Table 1.

[0101] Comparative Example 1

[0102] 3.9 g of silver nitrate and 0.5 g of palladium nitrate were placed in a beaker, and 100 g of distilled water was added to completely dissolve them, which was recorded as solution A. 50 g of white carbon black (BET specific surface area 200 m 2 / g), add 500g of distilled water and stir evenly, then slowly drop concentrated nitric acid with a dropper to adjust the pH value to 4, recorded as solution B; put 15g of sodium carbonate in another beaker and add 150g of distilled water to completely dissolve it, recorded as solution C; add solution A, solution B and solution C into a container for precipitation reaction, and keep the temperature at 40°C; after the precipitation is completed, keep the temperature at 60°C and age for 4 hours. The obtained catalyst precursor slurry is washed and filtered, dried at 120°C for 8 hours, and calcined at 500°C for 4 hours to obtain the target product catalyst.

[0103] Its specific surface area is 165m 2 / g.

[0104] The catalyst prepared above was made into 20-30 mesh size particles, loaded into a tubular reactor with a diameter of 12 mm, and activated for 4 hours in a hydrogen atmosphere at 230°C. Using dimethyl oxalate methanol solution as raw material, the reaction temperature was 180°C, and the liquid hourly space velocity was 0.4 h -1 , hydrogen-ester ratio 50:1, reaction pressure 2MPa, reaction results are shown in Table 1.

[0105] Comparative Example 2

[0106] 3.9 g of silver nitrate, 0.5 g of palladium nitrate and 7 g of indium nitrate hydrate were placed in a beaker, and 100 g of distilled water was added to completely dissolve them, which was recorded as solution A. 50 g of white carbon black (BET specific surface area 200 m 2 / g), add 500g of distilled water and stir evenly, then slowly drop concentrated nitric acid with a dropper to adjust the pH value to 4, recorded as solution B; put 15g of sodium carbonate in another beaker and add 150g of distilled water to completely dissolve it, recorded as solution C; add solution A, solution B and solution C into a container for precipitation reaction, and keep the temperature at 40°C; after the precipitation is completed, keep the temperature at 60°C and age for 4 hours. The obtained catalyst precursor slurry is washed and filtered, dried at 120°C for 8 hours, and calcined at 500°C for 4 hours to obtain the target product catalyst.

[0107] Its specific surface area is 168m 2 / g.

[0108] The catalyst prepared above was made into 20-30 mesh size particles, loaded into a tubular reactor with a diameter of 12 mm, and activated for 4 hours in a hydrogen atmosphere at 230°C. Using dimethyl oxalate methanol solution as raw material, the reaction temperature was 180°C, and the liquid hourly space velocity was 0.4 h -1 , hydrogen-ester ratio 50:1, reaction pressure 2MPa, reaction results are shown in Table 1.

[0109] Comparative Example 3

[0110] 3.9 g of silver nitrate, 0.5 g of palladium nitrate and 0.5 g of indium nitrate hydrate were placed in a beaker, and 100 g of distilled water was added to completely dissolve them, which was recorded as solution A. 50 g of white carbon black (BET specific surface area 100 m 2 / g), add 500g of distilled water and stir evenly, then slowly drop concentrated nitric acid with a dropper to adjust the pH value to 4, recorded as solution B; put 15g of sodium carbonate in another beaker and add 150g of distilled water to completely dissolve it, recorded as solution C; add solution A, solution B and solution C into a container for precipitation reaction, and keep the temperature at 40°C; after the precipitation is completed, keep the temperature at 60°C and age for 4 hours. The obtained catalyst precursor slurry is washed and filtered, dried at 120°C for 8 hours, and calcined at 500°C for 4 hours to obtain the target product catalyst.

[0111] Its specific surface area is 80m 2 / g.

[0112] The catalyst prepared above was made into 20-30 mesh size particles, loaded into a tubular reactor with a diameter of 12 mm, and activated for 4 hours in a hydrogen atmosphere at 230°C. Using dimethyl oxalate methanol solution as raw material, the reaction temperature was 180°C, and the liquid hourly space velocity was 0.4 h -1 , hydrogen-ester ratio 50:1, reaction pressure 2MPa, reaction results are shown in Table 1.

[0113] Table 1

[0114]

[0115]

[0116] Embodiment 11

[0117] 2 g of the catalyst prepared in Example 8 was weighed for stability test. It was activated in a hydrogen atmosphere at 250°C for 4 hours. Dimethyl oxalate methanol solution was used as raw material, the initial reaction temperature was 190°C, and the liquid hourly space velocity was 0.4 h -1 , hydrogen-ester ratio 50:1, reaction pressure 2MPa, the reaction results are listed in Table 2.

[0118] After 1000 hours of continuous reaction, the catalyst had a dimethyl oxalate conversion rate of greater than 99.0%, and a methyl glycolate selectivity of greater than 93%, showing good stability.

[0119] Table 2

[0120]

[0121] The above embodiments are only used to help understand the method and core idea of ​​the present invention. It should be noted that, for those skilled in the art, several improvements and modifications can be made to the present invention without departing from the principles of the present invention, and these improvements and modifications also fall within the scope of protection of the claims of the present invention.

Claims

1. Application of a hydrogenation catalyst as a catalyst for the hydrogenation of oxalate to prepare methyl glycolate, characterized in that: The hydrogenation catalyst comprises: an active component Ag-Pd, an In2O3 additive and a carrier; The preparation method of the hydrogenation catalyst comprises the following steps: S1) preparing a metal salt solution A, wherein the metal salt solution A contains silver ions, palladium ions and indium ions; Prepare carrier solution B; Prepare precipitant solution C; S2) mixing solution A, solution B and solution C to perform precipitation reaction to obtain a catalyst precursor slurry; S3) the catalyst precursor slurry is aged, washed, dried and calcined to obtain a hydrogenation catalyst; or S3') evaporating the catalyst precursor slurry by jet instantaneous pyrolysis, and then subjecting the evaporated material to hot air microspheroidization to obtain a hydrogenation catalyst; The jet instantaneous pyrolysis method is as follows: the catalyst precursor slurry is pumped to the atomizer, the atomizer evenly atomizes the slurry into ultra-micron droplets, which enter the tower, and the air enters the heating system, is heated to the temperature required by the process, and pyrolyzes into the required material after contacting the droplets.

2. The use according to claim 1, characterized in that: The mass percentage of the active component Ag in the catalyst is 0.01% to 18%; The mass percentage of the active component Pd in ​​the catalyst is 0.01% to 3%; The mass percentage of the In2O3 additive in the catalyst is 0.01% to 5%; The mass percentage of the carrier to the catalyst is 74% to 99.97%.

3. The use according to claim 1, characterized in that: The specific surface area of ​​the carrier is 150-600m 2 / g; The specific surface area of ​​the catalyst is 150-600m 2 / g.

4. The use according to claim 1, characterized in that: The carrier is selected from SiO2.

5. The use according to claim 1, characterized in that: The compound providing the silver ions is selected from silver nitrate or silver acetate; The compound providing the palladium ions is selected from palladium chloride, palladium nitrate or palladium acetate; The compound providing the indium ion is selected from indium nitrate; The carrier solution B is selected from a solution of silica sol, white carbon black or water glass; The precipitant is selected from sodium carbonate, sodium hydroxide, ammonium carbonate, ammonium bicarbonate, sodium bicarbonate, ammonia water or urea.

6. The use according to claim 1, characterized in that: The pH value of the carrier solution B is adjusted to 3-6 using an acidic or alkaline substance.

7. The use according to claim 1, characterized in that: The temperature of the precipitation reaction is 20 to 95°C; The aging temperature is 40 to 95° C., and the aging time is 0.5 to 12 hours; The calcination temperature is 300-800° C., and the calcination time is 0.5-12 hours.

8. The use according to claim 1, characterized in that: The inlet air temperature of the jet instant pyrolysis method is 80-250°C, and the jet pressure is 0.1-60 bar; The temperature of the hot air microspheroidization treatment is 80-150°C.

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