Supported catalyst, preparation method thereof and application of supported catalyst in preparation of dihydroxyacetone by glycerol oxidation

Abstract

The invention belongs to the technical field of chemical catalysis, and particularly relates to a supported catalyst, a preparation method of the supported catalyst and application of the supported catalyst to preparation of dihydroxyacetone through glycerol oxidation. The supported catalyst provided by the invention is an Au-based catalyst, the carrier of the supported catalyst is a copper-cerium composite oxide, the gold loading capacity is low, and even if the gold content is low, glycerol oxidation can be efficiently catalyzed in a heterogeneous and non-alkaline environment to prepare DHA. The invention also provides an application of the supported catalyst provided by the scheme or the supported catalyst prepared by the preparation method provided by the scheme in preparation of dihydroxyacetone by glycerol oxidation. The supported catalyst disclosed by the invention is used for preparing DHA through catalytic oxidation under mild reaction conditions by taking glycerol as a raw material, and is small in equipment corrosion and environment-friendly, so that the supported catalyst has wide application potential in the future.

Description

Technical Field

[0001] The invention belongs to the technical field of chemical catalysis, and in particular relates to a supported catalyst and a preparation method thereof, and application thereof in preparing dihydroxyacetone by oxidizing glycerol. Background Art

[0002] Dihydroxyacetone, referred to as DHA, occupies an important position in the fields of chemical industry, medicine, functional additives and cosmetics. In 1986, Bertland et al. successfully synthesized DHA for the first time using fermentation. Since then, microbial fermentation has become the main method for preparing DHA. However, the yield of the target product DHA of this method is not high. In contrast, the direct catalytic oxidation method uses catalysts and oxidants to prepare dihydroxyacetone through catalytic oxidation of glycerol, and obtains DHA in one step, which not only improves the utilization value of glycerol, but also has mild conditions, which is of great significance for promoting the efficient conversion and utilization of biomass resources.

[0003] The active components of the supported catalyst used for glycerol oxidation to DHA mainly include Pt, Pd or Au, etc. During the glycerol oxidation process, Pt and Pd will significantly reduce the catalytic reaction activity due to factors such as loss, sintering, oxidation and adsorption of acidic substances. Relatively speaking, Au-based catalysts have high stability, have a certain antioxidant capacity under high oxygen partial pressure, are not easily inactivated by oxygen poisoning, and have high selectivity for the oxidation of glycerol secondary hydroxyl groups, but require a large gold loading. Summary of the invention

[0004] The purpose of the present invention is to provide a supported catalyst and a preparation method thereof and application thereof in preparing dihydroxyacetone by oxidizing glycerol. The supported catalyst provided by the present invention has a low gold loading and can achieve efficient catalysis.

[0005] In order to achieve the above object, the present invention provides the following technical solutions:

[0006] The invention provides a supported catalyst, comprising a carrier and gold supported on the carrier; the carrier is a copper-cerium composite oxide; the supported amount of gold in the supported catalyst is 1-2wt%.

[0007] Preferably, the particle size of the carrier is 20 to 150 nm.

[0008] Preferably, the molar ratio of copper element to cerium element in the copper-cerium composite oxide is 1-20:1-20.

[0009] The present invention also provides a method for preparing the supported catalyst described in the above scheme, comprising the following steps:

[0010] Chloroauric acid, urea, a carrier and water are mixed for a deposition precipitation reaction, followed by aging and calcination to obtain a supported catalyst; the carrier is a copper-cerium composite oxide.

[0011] Preferably, the temperature of the deposition precipitation reaction is 40 to 80° C., and the insulation reaction time is 2 to 24 hours.

[0012] Preferably, the calcination temperature is 110-300° C., and the heat preservation calcination time is 4-6 hours.

[0013] Preferably, the preparation method of the copper-cerium composite oxide is: mixing copper salt, cerium salt, precipitant and water to carry out coprecipitation reaction, and then aging and calcining in sequence.

[0014] The present invention also provides the use of the supported catalyst described in the above scheme or the supported catalyst obtained by the preparation method described in the above scheme in the preparation of dihydroxyacetone by oxidation of glycerol.

[0015] In the present invention, the application comprises the following steps: mixing a supported catalyst, an oxidant, glycerol and a polar solvent to carry out a catalytic oxidation reaction to obtain dihydroxyacetone; the supported catalyst is the supported catalyst described in the above scheme or the supported catalyst obtained by the preparation method described in the above scheme.

[0016] Preferably, the molar ratio of the supported catalyst to glycerol is 1:10-100; the oxidant includes one or both of oxygen and air; and the pressure of the oxidant is 0.2-1 MPa.

[0017] The present invention provides a supported catalyst. The supported catalyst provided by the present invention is an Au-based catalyst, the carrier of which is a copper-cerium composite oxide, and the gold loading is low. Even when the gold content is low, the supported catalyst can efficiently catalyze the oxidation of glycerol to prepare DHA in a heterogeneous and non-alkaline environment.

[0018] The present invention also provides a method for preparing the supported catalyst of the above scheme. The preparation method provided by the present invention has simple steps, and the supported catalyst obtained is green, highly efficient, mild in use conditions, and has good stability.

[0019] The present invention also provides the use of the supported catalyst described in the above scheme or the supported catalyst obtained by the preparation method described in the above scheme in the preparation of dihydroxyacetone by oxidizing glycerol. Using the supported catalyst of the present invention, glycerol is used as a raw material, and DHA is prepared by catalytic oxidation under mild reaction conditions. It is less corrosive to equipment and is environmentally friendly, indicating that it has a wide range of application potential in the future. The test results of the embodiment show that for a supported catalyst with a gold loading of 1.2wt%, under an oxygen atmosphere of 0.5MPa, the reaction is carried out at 60°C for 8h, the conversion rate of glycerol is high, achieving 88.65%, and the selectivity of DHA is good, achieving 66.04%. DETAILED DESCRIPTION

[0020] The invention provides a supported catalyst, comprising a support and gold supported on the support.

[0021] In the present invention, the particle size of the carrier is preferably 20 to 150 nm, specifically 20 nm, 50 nm, 70 nm, 90 nm, 110 nm, 130 nm or 150 nm; the carrier is a copper-cerium composite oxide; the copper-cerium composite oxide preferably includes CuO and CeO 2 .

[0022] In the present invention, the method for preparing the copper-cerium composite oxide is preferably: mixing copper salt, cerium salt, precipitant and water to perform a coprecipitation reaction, followed by aging and calcining.

[0023] In the present invention, the copper salt is preferably copper nitrate; and the cerium salt is preferably cerium nitrate.

[0024] In the present invention, the mass ratio of the copper salt to the cerium salt is preferably 12-23:4-21, specifically 12:4, 12:8, 12:12, 12:16, 12:21, 16:4, 16:8, 16:12, 16:16, 16:21, 20:4, 20:8, 20:12, 20:16, 20:21, 23:4, 23:8, 23:12, 23:16 or 23:21.

[0025] In the present invention, the precipitant preferably includes one or both of sodium carbonate and sodium hydroxide; the mass ratio of the copper salt to the precipitant is preferably 25 to 10:13, specifically 22:13, 21:13, 20:13, 18:13 or 12:13.

[0026] In the present invention, the mass ratio of the nitrate to water is preferably 20 to 35:100, specifically 25:100, 26:100, 27:100, 28:100 or 33:100.

[0027] In the present invention, the copper salt, cerium salt, precipitant and water are preferably mixed by premixing copper nitrate, cerium nitrate and part of water to obtain solution A, premixing the precipitant and the remaining part of water to obtain solution B, and mixing the solution A and solution B.

[0028] In the present invention, the coprecipitation reaction is preferably carried out under stirring conditions; the coprecipitation reaction is preferably carried out in a water bath condition; the temperature of the coprecipitation reaction is preferably 40-80°C, specifically 70°C, and the insulation reaction time is preferably 0.5-24h, specifically 4h or 16h.

[0029] In the present invention, the aging temperature is preferably 0.5 to 24 hours, specifically 5 hours or 12 hours, and the heat preservation aging time is preferably 0.5 to 24 hours, specifically 1 hour or 12 hours.

[0030] In the present invention, after aging, the product system preferably also includes cooling, solid-liquid separation, washing, drying and grinding in sequence; the final temperature of the cooling is preferably room temperature; the solid-liquid separation is preferably filtration; the washing is preferably until the filtrate is neutral (pH value is 7); the drying temperature is preferably 100-120°C, specifically 110°C, and the heat preservation and drying time is preferably 8-24h, specifically 12h.

[0031] In the present invention, the calcination temperature is preferably 500-700°C, specifically 500°C, 520°C, 540°C, 560°C, 580°C, 600°C, 620°C, 640°C, 660°C, 680°C or 700°C, and the heat preservation calcination time is preferably 4-6h, specifically 4h or 5h.

[0032] In the present invention, the molar ratio of copper element to cerium element in the copper-cerium composite oxide is preferably 1-20:1-20, specifically 1:1, 1:5, 1:10, 1:15, 1:20, 5:1, 10:1, 15:1 or 20:1.

[0033] In the present invention, the gold loading in the supported catalyst is preferably 1-2 wt%, specifically 1.0 wt%, 1.2 wt%, 1.5 wt%, 1.8 wt% or 2 wt%.

[0034] The present invention also provides a method for preparing the supported catalyst described in the above scheme, comprising the following steps:

[0035] Chloroauric acid, urea, a carrier and water are mixed for a deposition precipitation reaction, followed by aging and calcination to obtain a supported catalyst; the carrier is a copper-cerium composite oxide.

[0036] The present invention mixes chloroauric acid, urea, a carrier and water (referred to as the first mixing) to carry out a sedimentation reaction. In the present invention, the mass ratio of the carrier to chloroauric acid is preferably not less than 100:3, and specifically can be 100:2.8, 100:2.6, 100:2.4, 100:2.1, 100:1.8, 100:1.5, 100:1.2, 100:1, 100:0.7, 100:0.5, 100:0.2 or 100:0.1.

[0037] In the present invention, the mass ratio of the carrier to urea is preferably not less than 1:4, and can be specifically 1:4, 1:3.6, 1:3.2, 1:3, 1:2.7, 1:2.4, 1:2.1, 1:2, 1:1.8, 1:1.5, 1:1.2, 1:1, 1:0.8, 1:0.5, 1:0.3 or 1:0.1. In the present invention, nitrate is precipitated by adding urea as a precipitant.

[0038] In the present invention, the mass ratio of the carrier to water is preferably 1:50 to 100, specifically 1:50, 1:60, 1:70, 1:80, 1:90 or 1:100.

[0039] In the present invention, the first mixing is preferably stirring mixing.

[0040] In the present invention, the temperature of the deposition precipitation reaction is preferably 40-80°C, specifically 40°C, 50°C, 60°C, 70°C or 80°C, and the insulation reaction time is preferably 2-24h, specifically 2h, 6h, 10h, 15h, 18h, 21h or 24h.

[0041] After the deposition precipitation reaction, the present invention sequentially ages and calcines the product obtained by the deposition precipitation reaction to obtain a supported catalyst. In the present invention, the aging temperature is preferably room temperature, and the heat preservation aging time is preferably 2 to 24 hours, specifically 2 hours, 6 hours, 10 hours, 12 hours, 15 hours, 18 hours, 21 hours or 24 hours.

[0042] In the present invention, after aging, the aging product is preferably subjected to post-treatment; the post-treatment preferably comprises: washing and drying the aging product in sequence after solid-liquid separation; the solid-liquid separation is preferably filtration; the washing is preferably performed until no chloride ions are left in the filtrate; the drying temperature is preferably 100 to 120°C, specifically 110°C, and the heat preservation and drying time is preferably 2 to 24h, specifically 4h, 8h, 12h, 16h or 22h.

[0043] In the present invention, the calcination temperature is preferably 110-300°C, specifically 110°C, 150°C, 180°C, 210°C, 240°C, 270°C or 300°C, and the heat preservation calcination time is preferably 4-6h, specifically 5h.

[0044] The present invention also provides the use of the supported catalyst described in the above scheme or the supported catalyst obtained by the preparation method described in the above scheme in the preparation of dihydroxyacetone by oxidation of glycerol.

[0045] In the present invention, the application preferably includes the following steps: mixing a supported catalyst, an oxidant, glycerol and a polar solvent to carry out a catalytic oxidation reaction to obtain dihydroxyacetone; the supported catalyst is the supported catalyst described in the above scheme or the supported catalyst obtained by the preparation method described in the above scheme.

[0046] In the present invention, the molar ratio of the supported catalyst to glycerol is preferably 1:10-100, specifically 1:10, 1:20, 1:30, 1:40, 1:50, 1:60, 1:70, 1:80, 1:90 or 1:100.

[0047] In the present invention, the oxidant preferably includes one or both of oxygen and air; the pressure of the oxidant is preferably 0.2-1 MPa, specifically 0.2 MPa, 0.4 MPa, 0.6 MPa, 0.8 MPa or 1.0 MPa.

[0048] In the present invention, the polar solvent is preferably water; the molar ratio of the glycerol to the polar solvent is preferably 1:10.

[0049] In the present invention, the equipment for the catalytic oxidation reaction is preferably an intermittent reactor; the temperature of the catalytic oxidation reaction is preferably 10-100°C, specifically 10°C, 30°C, 50°C, 70°C, 90°C or 100°C, and the insulation reaction time is preferably 1-12h, specifically 1h, 3h, 5h, 7h, 9h or 12h.

[0050] In the present invention, the glycerol conversion rate, DHA selectivity and yield are calculated according to Formula I to Formula III (n is the amount of substance):

[0051] Glycerol conversion rate = [(n 反应前甘油 -n 反应后甘油 ) / n 反应前甘油 ]×100%Formula I;

[0052] DHA selectivity = [n DHA / (n 反应前甘油 -n 反应后甘油 )]×100% formula II;

[0053] DHA yield = glycerol conversion rate × DHA selectivity formula III.

[0054] In order to further illustrate the present invention, the scheme of the present invention is described in detail below in conjunction with embodiments, but they should not be understood as limiting the scope of protection of the present invention.

[0055] In the specific embodiments of the present invention, the chemical reagents used are commercially available unless otherwise specified; the reaction products are detected by high performance liquid chromatography (LC-10Avp) using a chromatographic column of HPX-87H, differential refractive index detector (RID-10A) and ultraviolet detector (SPD-10Avp), sulfuric acid was used as the mobile phase, the flow rate was 0.6 mL / min, and the column temperature was 60 °C.

[0056] Example 1

[0057] Dissolve 12.08g of copper nitrate and 21.711g of cerium nitrate in 100g of deionized water and stir for 0.5h to prepare solution A. Dissolve 13.25g of sodium carbonate in 100g of deionized water and stir for 0.5h to prepare solution B. Coprecipitate solution A and solution B in a 70℃ water bath with stirring, then age for 1h. After the mixture cools to room temperature, filter the product, wash until the filtrate is neutral, and then dry at 110℃ for 12h; grind the dried sample into powder and calcine at 600℃ for 4h to obtain the carrier.

[0058] Take 1g of the above carrier, disperse it in 50g of water, add 1.2mL of chloroauric acid (10mg / mL) solution, then add 1.46g of urea, stir and heat the mixture to 80°C, maintain for 6h, then cool the mixture to room temperature and age for 12h; filter the aged mixture, wash until there is no chloride ion in the filtrate to obtain a filter cake; dry the obtained filter cake at 110°C for 4h, and calcine the dried sample at 200°C for 5h to obtain a supported catalyst, recorded as A1.

[0059] 0.5 g of the supported catalyst of this example and 19.5 g of glycerol aqueous solution (0.1 mol / L) were placed in a reactor and reacted at 60° C. in 0.5 MPa oxygen for 8 h. After the reaction, the mixed solution was centrifuged and a small amount of the supernatant was taken out for high performance liquid chromatography analysis. The analysis results are shown in Table 1.

[0060] Example 2

[0061] Dissolve 18.12g of copper nitrate and 10.86g of cerium nitrate in 100g of deionized water and stir for 0.5h to prepare solution A. Dissolve 13.25g of sodium carbonate in 100g of deionized water and stir for 0.5h to prepare solution B. Co-precipitate solution A and solution B in a 70℃ water bath with stirring, then age for 1h. After the mixture cools to room temperature, filter the product, wash until the filtrate is neutral, and then dry at 110℃ for 12h; grind the dried sample into powder and calcine at 600℃ for 4h to obtain the carrier.

[0062] Take 1g of the above carrier, disperse it in 50g of water, add 1.2mL of chloroauric acid (10mg / mL) solution, then add 1.46g of urea, stir and heat the mixture to 80°C, maintain for 6h, then cool the mixture to room temperature and age for 12h; filter the aged mixture, wash until there is no chloride ion in the filtrate to obtain a filter cake; dry the obtained filter cake at 110°C for 4h, and calcine the dried sample at 200°C for 5h to obtain a supported catalyst, recorded as A2.

[0063] 0.5 g of the supported catalyst of this example and 19.5 g of glycerol aqueous solution (0.1 mol / L) were placed in a reactor and reacted at 60° C. in 0.5 MPa oxygen for 8 h. After the reaction, the mixed solution was centrifuged and a small amount of the supernatant was taken out for high performance liquid chromatography analysis. The analysis results are shown in Table 1.

[0064] Example 3

[0065] Dissolve 20.13g of copper nitrate and 7.24g of cerium nitrate in 100g of deionized water and stir for 0.5h to prepare solution A. Dissolve 13.25g of sodium carbonate in 100g of deionized water and stir for 0.5h to prepare solution B. Coprecipitate solution A and solution B in a 70℃ water bath with stirring, then age for 1h. After the mixture cools to room temperature, filter the product, wash until the filtrate is neutral, and then dry at 110℃ for 12h; grind the dried sample into powder and calcine at 600℃ for 4h to obtain the carrier.

[0066] Take 1g of the above carrier, disperse it in 50g of water, add 1.2mL of chloroauric acid (10mg / mL) solution, then add 1.46g of urea, stir and heat the mixture to 80°C, maintain for 6h, then cool the mixture to room temperature and age for 12h; filter the aged mixture, wash until there is no chloride ion in the filtrate to obtain a filter cake; dry the obtained filter cake at 110°C for 4h, and calcine the dried sample at 200°C for 5h to obtain a supported catalyst, recorded as A3.

[0067] 0.5 g of the supported catalyst of this example and 19.5 g of glycerol aqueous solution (0.1 mol / L) were placed in a reactor and reacted at 80° C. in 0.5 MPa oxygen for 8 h. After the reaction, the mixed solution was centrifuged and a small amount of the supernatant was taken out for high performance liquid chromatography analysis. The analysis results are shown in Table 1.

[0068] Example 4

[0069] Dissolve 21.14g of copper nitrate and 5.43g of cerium nitrate in 100g of deionized water and stir for 0.5h to prepare solution A. Dissolve 13.25g of sodium carbonate in 100g of deionized water and stir for 0.5h to prepare solution B. Co-precipitate solution A and solution B in a 70℃ water bath with stirring, then age for 1h. After the mixture cools to room temperature, filter the product, wash until the filtrate is neutral, and then dry at 110℃ for 12h; grind the dried sample into powder and calcine at 600℃ for 4h to obtain the carrier.

[0070] Take 1g of the above carrier, disperse it in 50g of water, add 1.2mL of chloroauric acid (10mg / mL) solution, then add 1.46g of urea, stir and heat the mixture to 80°C, maintain for 6h, then cool the mixture to room temperature and age for 12h; filter the aged mixture, wash until there is no chloride ion in the filtrate to obtain a filter cake; dry the obtained filter cake at 110°C for 4h, and calcine the dried sample at 200°C for 5h to obtain a supported catalyst, recorded as A4.

[0071] 0.5 g of the supported catalyst of this example and 19.5 g of glycerol aqueous solution (0.1 mol / L) were placed in a reactor and reacted at 50° C. for 6 h in 0.5 MPa oxygen. After the reaction, the mixed solution was centrifuged and a small amount of the supernatant was taken out for high performance liquid chromatography analysis. The analysis results are shown in Table 1.

[0072] Example 5

[0073] Dissolve 21.74g of copper nitrate and 4.34g of cerium nitrate in 100g of deionized water and stir for 0.5h to prepare solution A. Dissolve 13.25g of sodium carbonate in 100g of deionized water and stir for 0.5h to prepare solution B. Co-precipitate solution A and solution B in a 70℃ water bath with stirring, then age for 1h. After the mixture cools to room temperature, filter the product, wash until the filtrate is neutral, and then dry at 110℃ for 12h; grind the dried sample into powder and calcine at 600℃ for 4h to obtain the carrier.

[0074] Take 1g of the above carrier, disperse it in 50g of water, add 1.2mL of chloroauric acid (10mg / mL) solution, then add 1.46g of urea, stir and heat the mixture to 80°C, maintain for 6h, then cool the mixture to room temperature and age for 12h; filter the aged mixture, wash until there is no chloride ion in the filtrate to obtain a filter cake; dry the obtained filter cake at 110°C for 4h, and calcine the dried sample at 200°C for 5h to obtain a supported catalyst, recorded as A5.

[0075] 0.5 g of the supported catalyst of this example and 19.5 g of glycerol aqueous solution (0.1 mol / L) were placed in a reactor and reacted at 60° C. in 1 MPa oxygen for 8 h. After the reaction, the mixed solution was centrifuged and a small amount of the supernatant was taken out for high performance liquid chromatography analysis. The analysis results are shown in Table 1.

[0076] Example 6

[0077] Dissolve 22.15g of copper nitrate and 3.62g of cerium nitrate in 100g of deionized water and stir for 0.5h to prepare solution A. Dissolve 13.25g of sodium carbonate in 100g of deionized water and stir for 0.5h to prepare solution B. Co-precipitate solution A and solution B in a 70℃ water bath with stirring, then age for 1h. After the mixture cools to room temperature, filter the product, wash until the filtrate is neutral, and then dry at 110℃ for 12h; grind the dried sample into powder and calcine at 600℃ for 4h to obtain the carrier.

[0078] Take 1g of the above carrier, disperse it in 50g of water, add 1.2mL of chloroauric acid (10mg / mL) solution, then add 1.46g of urea, stir and heat the mixture to 80°C, maintain for 6h, then cool the mixture to room temperature and age for 12h; filter the aged mixture, wash until there is no chloride ion in the filtrate to obtain a filter cake; dry the obtained filter cake at 110°C for 4h, and calcine the dried sample at 200°C for 5h to obtain a supported catalyst, recorded as A6.

[0079] 0.5 g of the supported catalyst of this example and 19.5 g of glycerol aqueous solution (0.1 mol / L) were placed in a reactor and reacted at 60° C. in 0.5 MPa oxygen for 10 h. After the reaction, the mixed solution was centrifuged and a small amount of the supernatant was taken out for high performance liquid chromatography analysis. The analysis results are shown in Table 1.

[0080] Comparative Example 1

[0081] Dissolve 21.74g of copper nitrate and 4.34g of cerium nitrate in 100g of deionized water and stir for 0.5h to prepare solution A. Dissolve 13.25g of sodium carbonate in 100g of deionized water and stir for 0.5h to prepare solution B. Co-precipitate solution A and solution B in a 70℃ water bath with stirring, then age for 1h. After the mixture cools to room temperature, filter the product, wash until the filtrate is neutral, and then dry at 110℃ for 12h; grind the dried sample into powder and calcine at 600℃ for 4h to obtain the carrier.

[0082] Take 1g of the above carrier, disperse it in 50g of water, add 3mL of chloroauric acid (10mg / mL) solution, then add 3.66g of urea, stir and heat the mixture to 80°C, maintain for 6h, then cool the mixture to room temperature and age for 12h; filter the aged mixture, wash until there is no chloride ion in the filtrate to obtain a filter cake; dry the obtained filter cake at 110°C for 4h, and calcine the dried sample at 200°C for 5h to obtain a supported catalyst, recorded as A7.

[0083] 0.5 g of the supported catalyst of this comparative example and 19.5 g of glycerol aqueous solution (0.1 mol / L) were placed in a reactor and reacted at 60° C. in 0.5 MPa oxygen for 8 h. After the reaction, the mixed solution was centrifuged and a small amount of the supernatant was taken out for high performance liquid chromatography analysis. The analysis results are shown in Table 1.

[0084] Comparative Example 2

[0085] Dissolve 21.74g of copper nitrate and 4.34g of cerium nitrate in 100g of deionized water and stir for 0.5h to prepare solution A. Dissolve 13.25g of sodium carbonate in 100g of deionized water and stir for 0.5h to prepare solution B. Co-precipitate solution A and solution B in a 70℃ water bath with stirring, then age for 1h. After the mixture cools to room temperature, filter the product, wash until the filtrate is neutral, and then dry at 110℃ for 12h; grind the dried sample into powder and calcine at 600℃ for 4h to obtain the carrier.

[0086] Take 1g of the above carrier, disperse it in 50g of water, add 0.5mL of chloroauric acid (10mg / mL) solution, then add 0.61g of urea, stir and heat the mixture to 80°C, maintain for 6h, then cool the mixture to room temperature and age for 12h; filter the aged mixture, wash until there is no chloride ion in the filtrate to obtain a filter cake; dry the obtained filter cake at 110°C for 4h, and calcine the dried sample at 200°C for 5h to obtain a supported catalyst, recorded as A8.

[0087] 0.5 g of the supported catalyst of this comparative example and 19.5 g of glycerol aqueous solution (0.1 mol / L) were placed in a reactor and reacted at 60° C. in 0.5 MPa oxygen for 8 h. After the reaction, the mixed solution was centrifuged and a small amount of the supernatant was taken out for high performance liquid chromatography analysis. The analysis results are shown in Table 1.

[0088] Table 1 Reaction results of preparing DHA by oxidizing glycerol in Examples 1 to 6 and Comparative Examples 1 to 2

[0089] project Catalyst formulation Gold loading % Glycerol conversion rate % DHA Selective % DHA yield% Example 1 A1 1.2 57.07 37.81 21.57 Example 2 A2 1.2 88.23 44.75 39.49 Example 3 A3 1.2 71.26 55.56 39.59 Example 4 A4 1.2 88.65 52.47 46.52 Example 5 A5 1.2 86.70 66.04 57.25 Example 6 A6 1.2 71.16 58.08 41.33 Comparative Example 1 A7 3 73.68 65.41 48.19 Comparative Example 2 A8 0.5 21.12 26.93 5.69

[0090] It can be seen from Table 1 that, compared with Comparative Example 1, the supported catalyst provided by the present invention has a high glycerol conversion rate, good DHA selectivity, and a higher yield; it can be seen from the data of Comparative Example 2 that when the gold content of the supported catalyst is lower than the range of the present invention, the glycerol conversion rate, DHA selectivity, and DHA yield are very low.

[0091] It can be seen from the above examples that the supported catalyst provided by the present invention can achieve the goal of preparing dihydroxyacetone by catalytic oxidation of glycerol under mild conditions and with high efficiency in a non-alkaline medium at a low gold content, thereby effectively reducing environmental pollution, not corroding equipment, having low requirements for equipment, and being easy to recycle and regenerate the catalyst. The glycerol conversion rate is 88.65%, and the DHA selectivity is 66%, which is suitable for industrial production.

[0092] Although the above embodiment describes the present invention in detail, it is only a part of the embodiments of the present invention, not all of the embodiments. Other embodiments can be obtained based on this embodiment without creativity, and these embodiments all fall within the protection scope of the present invention.

Claims

1. A supported catalyst, characterized in that The invention comprises a carrier and gold loaded on the carrier; the carrier is a copper-cerium composite oxide; and the loading amount of gold in the loaded catalyst is 1-2 wt%.

2. The supported catalyst according to claim 1, characterized in that The particle size of the carrier is 20 to 150 nm.

3. The supported catalyst according to claim 1 or 2, characterized in that The molar ratio of copper element to cerium element in the copper-cerium composite oxide is 1-20:1-20.

4. The method for preparing a supported catalyst according to any one of claims 1 to 3, characterized in that: The following steps are involved: Chloroauric acid, urea, a carrier and water are mixed for a deposition precipitation reaction, followed by aging and calcination to obtain a supported catalyst; the carrier is a copper-cerium composite oxide.

5. The preparation method according to claim 4, characterized in that: The temperature of the deposition precipitation reaction is 40-80° C., and the insulation reaction time is 2-24 hours.

6. The preparation method according to claim 4 or 5, characterized in that: The calcination temperature is 110-300° C., and the heat preservation calcination time is 4-6 hours.

7. The preparation method according to claim 4, characterized in that: The preparation method of the copper-cerium composite oxide comprises: mixing copper salt, cerium salt, precipitant and water to carry out coprecipitation reaction, and then carrying out aging and roasting in sequence.

8. Use of the supported catalyst according to any one of claims 1 to 3 or the supported catalyst obtained by the preparation method according to any one of claims 4 to 7 in the oxidation of glycerol to prepare dihydroxyacetone.

9. The use according to claim 8, characterized in that: The method comprises the following steps: mixing a supported catalyst, an oxidant, glycerol and a polar solvent to carry out a catalytic oxidation reaction to obtain dihydroxyacetone; the supported catalyst is the supported catalyst according to any one of claims 1 to 3 or the supported catalyst obtained by the preparation method according to any one of claims 4 to 7.

10. The use according to claim 9, characterized in that: The molar ratio of the supported catalyst to glycerol is 1:10-100; the oxidant comprises one or both of oxygen and air; and the pressure of the oxidant is 0.2-1 MPa.