A process for producing hydrogen peroxide in a fully acidic fixed bed

Abstract

This invention relates to the field of hydrogen peroxide manufacturing technology, specifically disclosing a fully acidic fixed-bed hydrogen peroxide production process. The process includes: preparing a fully acidic working solution containing a compound anthraquinone and an acid stabilizer; conducting a fixed-bed hydrogenation reaction under fully acidic conditions in the main circulation of the working solution using a dedicated catalyst; subsequently performing oxidation and countercurrent extraction to directly obtain the hydrogen peroxide product; the raffinate enters an independent regeneration system, is treated with a compound regenerator and its pH value adjusted before being returned to the circulation system. This invention avoids contact with alkaline solutions through a fully acidic environment, significantly improving the safety of the production process, while effectively inhibiting the formation of degradation products, optimizing the performance of the working solution, and improving the capacity and stability of the equipment. It also has the advantages of low energy consumption, low pollution discharge, and simple operation.

Description

Technical Field

[0001] This invention relates to the field of hydrogen peroxide manufacturing technology, and more specifically, to a fully acidic fixed-bed hydrogen peroxide production process. Background Technology

[0002] Hydrogen peroxide (H₂O₂) is a typical green chemical product, with its decomposition products being only water and oxygen, producing no secondary pollution. It has irreplaceable application value in fields such as paper bleaching, fine chemical synthesis, environmental pollutant degradation, and electronic industry cleaning. Currently, the anthraquinone process is the mainstream technology for producing hydrogen peroxide in the industrial sector. This technology uses anthraquinone derivatives as the working medium and forms a circular production system through processes such as working solution preparation, hydrogenation, oxidation, extraction, and working solution post-treatment. Fixed-bed reactors are widely used in the hydrogenation stage of the anthraquinone process for hydrogen peroxide production due to their stable operation and low catalyst loss.

[0003] Traditional fixed-bed anthraquinone hydrogen peroxide production often employs an acid-base alternating process. During the working fluid circulation, anthraquinone undergoes repeated hydrogenation and oxidation reactions, easily generating anthraquinone degradation products. To maintain hydrogenation efficiency, an alkaline washing process is required to regenerate the degradation products into effective anthraquinone using alkaline solution and activated alumina, while simultaneously removing accumulated byproducts from the working fluid. However, this process has significant limitations: hydrogen peroxide is chemically extremely unstable in an alkaline environment. If hydrogen peroxide accidentally enters the alkaline washing process due to equipment leaks or operational fluctuations, it can easily trigger a violent decomposition reaction, accompanied by significant heat release, rapid volume expansion, and oxygen release, directly threatening production safety. Furthermore, frequent switching between acid and alkaline environments in the working fluid exacerbates the formation rate of anthraquinone degradation products, leading to deterioration of the working fluid's properties and affecting the stability of subsequent extraction processes. The alkaline washing process also increases energy consumption and wastewater discharge. Therefore, this invention provides a fully acidic fixed-bed hydrogen peroxide production process to solve the aforementioned technical problems. Summary of the Invention

[0004] The purpose of this invention is to provide a fully acidic fixed-bed hydrogen peroxide production process. By avoiding contact with alkaline solutions in a fully acidic environment, the safety of the production process is significantly improved. At the same time, it effectively inhibits the formation of degradation products, optimizes the performance of the working fluid, and improves the capacity and stability of the device. It has the advantages of low energy consumption, less sewage discharge, and simple operation.

[0005] This invention provides a fully acidic fixed-bed hydrogen peroxide production process, employing the following technical solution:

[0006] S1. Dissolve 2-ethylanthraquinone, 2-pentylanthraquinone and 2-ethyltetrahydroanthraquinone in a mixed solvent, add an acidic stabilizer, and stir at 200-300 rpm for 1-3 hours at 45-55℃ to obtain a fully acidic working solution.

[0007] S2. The fully acidic working fluid is passed into a fixed-bed hydrogenation tower filled with catalyst, and hydrogenated liquid is obtained after the reaction.

[0008] S3. The hydrogenated liquid is introduced into the oxidation reactor, and pure water and oxygen are introduced simultaneously. The volume ratio of pure water to hydrogenated liquid is 1:(8-12), and the molar ratio of oxygen to anthraquinone in the hydrogenated liquid is (1.2-1.5):1. The mixture is kept at 35-45℃ for 20-40 minutes to oxidize anthraquinone into hydrogen peroxide, which is simultaneously extracted by pure water countercurrently to obtain hydrogen peroxide product.

[0009] S4. The raffinate after S3 treatment is introduced into a regeneration system independent of the main circulation and regenerated at 50-70℃ for 2-8 hours. -1 The volume hourly space velocity (VHSV) passes through a regeneration bed filled with a composite regenerant. After treatment, the pH of the working solution is adjusted back to 4.0-5.0 by adding phosphoric acid. After passing the test, it is returned to the system for recycling.

[0010] Preferably, step S1 comprises, by weight, 12-15 parts of 2-ethylanthraquinone, 2-4 parts of 2-pentylanthraquinone, 1-3 parts of 2-ethyltetrahydroanthraquinone, 50-55 parts of mixed solvent and 0.3-0.5 parts of acid stabilizer.

[0011] Preferably, in step S1, the mixed solvent consists of 12-15 parts of heavy aromatic hydrocarbons, 6-8 parts of trioctyl phosphate and 4-6 parts of tetrabutylurea, and the acid stabilizer consists of 1-3 parts of phytic acid, 0.6-0.8 parts of aminotrimethylphosphonic acid and 0.1-0.3 parts of silicotungstic acid.

[0012] Preferably, in step S2, the hydrogenation reaction temperature is 55-65℃, the system pressure is 0.25-0.35MPa, the volume ratio of hydrogen to working fluid is 4-6:1, and the volume hourly space velocity of the working fluid is 8-12h. -1 .

[0013] Preferably, the catalyst preparation step in step S2 is as follows:

[0014] A1. Mix phenol and formaldehyde solution, adjust pH to 8.0-8.5, stir at 80-85℃ and 150-180rpm for 2-2.5h to obtain prepolymer, cool and set aside.

[0015] A2. Dissolve zirconium oxychloride and yttrium nitrate in deionized water, slowly add phosphoric acid solution while stirring, react at 50-55℃ for 1-2 hours, and adjust the pH to 3.0-3.5 to obtain a composite sol;

[0016] A3. Mix the prepolymer with the composite sol, add polyethylene glycol 600, stir at 60-65℃ for 2-3 hours to form a hybrid sol, and after curing and drying, calcine at 350-400℃ for 3-4 hours to obtain the composite carrier.

[0017] A4. Disperse the composite support in deionized water, add disodium ethylenediaminetetraacetate, stir at 40-45℃ for 30-40 min, add palladium nitrate solution, continue stirring for 1-3 h, then add formaldehyde and react at 55-60℃ for 2-3 h. After filtration, washing and drying, the catalyst is obtained.

[0018] Preferably, step A1 comprises 15-20 parts by weight of phenol and 25-30 parts by weight of 35-40 wt% formaldehyde solution, and step A2 comprises 8-12 parts by weight of zirconium oxychloride, 0.3-0.5 parts by weight of yttrium nitrate, 40-50 parts by weight of deionized water and 23-5 parts by weight of 82-86 wt% phosphoric acid solution.

[0019] Preferably, step A3 comprises 4-8 parts by weight of prepolymer, 10-15 parts by weight of composite sol and 0.2-0.5 parts by weight of polyethylene glycol 600, and step A4 comprises 8-12 parts by weight of composite carrier, 20-25 parts by weight of deionized water, 1-2 parts by weight of disodium ethylenediaminetetraacetate, 5-8 parts by weight of 9-13 wt% palladium nitrate solution and 3-5 parts by weight of formaldehyde.

[0020] Preferably, the preparation step of the composite regenerant in step S4 is as follows:

[0021] (1) Aluminum isopropoxide, tetraethyl orthosilicate and lanthanum nitrate were hydrolyzed at pH 3.0-3.5 and 60-65℃ for 1-3 hours, and then γ-aminopropyltriethoxysilane was added to continue the reaction for 2-3 hours. After drying, the mixture was calcined at 550-600℃ for 4-5 hours to obtain a composite carrier.

[0022] (2) Disperse the composite carrier in deionized water, add zinc nitrate solution and tetrabutyl titanate ethanol solution dropwise at 50-55℃, stir and adsorb, adjust the pH to neutral for in-situ precipitation, then add phosphoric acid and react for 1-1.5h, and finally obtain the composite regenerator by filtration, washing and drying.

[0023] Preferably, in step (1), the ingredients are 25-30 parts by weight of aluminum isopropoxide, 10-15 parts of tetraethyl orthosilicate, 0.8-1.2 parts of lanthanum nitrate and 2-3 parts of γ-aminopropyltriethoxysilane.

[0024] Preferably, in step (2), the components by weight are 10-15 parts of composite carrier, 25-30 parts of deionized water, 2-4 parts of 20wt% zinc nitrate solution, 0.8-1.2 parts of 15wt% tetrabutyl titanate ethanol solution and 3-5 parts of 80-85wt% phosphoric acid.

[0025] In summary, the present invention has the following beneficial effects:

[0026] 1. The fully acidic fixed-bed hydrogen peroxide production process provided by this invention involves preparing a fully acidic working solution containing complex anthraquinones and an acidic stabilizer. After fixed-bed hydrogenation and oxidative countercurrent extraction, the raffinate is introduced into an independent regeneration system for treatment and pH adjustment to achieve circulation. This process constructs a fully acidic working solution circulation system, completely avoiding the risk of contact between the alkaline washing process and hydrogen peroxide in traditional processes, eliminating the safety hazard of violent hydrogen peroxide decomposition caused by an alkaline environment from the root. At the same time, the acidic stabilizer can effectively complex trace metal ions in the working solution, inhibit the catalytic decomposition of hydrogen peroxide, and slow down the formation rate of anthraquinone degradation products from the source, preventing the physical properties of the working solution from deteriorating due to the accumulation of degradation products, ensuring the stable operation of subsequent extraction processes, thereby improving the overall capacity and continuous operation stability of the equipment. Moreover, the design without an alkaline washing process significantly reduces energy consumption and pollution discharge, meeting the requirements of green production.

[0027] 2. The catalyst of this invention is prepared by using a hybrid support made from a phenolic resin prepolymer and a zirconium phosphate-yttrium composite sol, followed by chelation of the loaded palladium active component. This catalyst exhibits excellent acid tolerance and hydrogenation selectivity because the composite structure formed by the phenolic resin, zirconium phosphate, and yttrium in the hybrid support maintains support stability in a fully acidic hydrogenation environment, avoiding structural damage caused by acid corrosion in traditional supports. Simultaneously, disodium ethylenediaminetetraacetate acts as a chelating agent during preparation, forming a stable chelate with palladium ions, ensuring uniform dispersion of the palladium active component on the support surface, reducing active site aggregation, improving hydrogenation reaction efficiency, and precisely catalyzing the hydrogenation of anthraquinone to the target hydrogen anthraquinone, inhibiting side reactions such as excessive hydrogenation, and further reducing the amount of degradation products generated.

[0028] 3. The composite regenerator of this invention is prepared by hydrolyzing aluminum isopropoxide, tetraethyl orthosilicate, and lanthanum nitrate, followed by silane modification and calcination to obtain a composite carrier, which is then modified by coating with zinc-titanium composite oxide and phosphoric acid. This regenerator can efficiently regenerate anthraquinone degradation products in the working fluid and maintain a fully acidic cycle. The key lies in the fact that after the carrier is modified with silane and doped with lanthanum, the active sites formed on the surface enhance the adsorption capacity for degradation products; while the zinc-titanium composite oxide and phosphoric acid coating layer have good structural stability and acid compatibility, which can firmly adsorb and transform degradation products. Regeneration can be achieved without relying on alkaline conditions, thus avoiding the risk of introducing alkaline solution into the main circulation, and ensuring that the regenerated working fluid meets the requirements of a fully acidic cycle through phosphoric acid backflushing, ensuring long-term stable working fluid circulation performance and reducing working fluid loss. Detailed Implementation

[0029] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. 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 of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0030] Unless otherwise specified, the experimental methods used in the following examples are conventional methods, and the experimental materials used, unless otherwise specified, were all purchased from conventional biochemical reagent stores. All quantitative experiments in the following examples were performed in triplicate, and the data are the average of the three replicates or the average ± standard deviation.

[0031] Polyethylene glycol 600, purchased from Shanghai Vieite Biotechnology Co., Ltd., CAS number ;

[0032] Example 1

[0033] This embodiment provides a fully acidic fixed-bed hydrogen peroxide production process, employing the following technical solution:

[0034] S1. Dissolve 15 parts of 2-ethylanthraquinone, 2 parts of 2-pentylanthraquinone and 1 part of 2-ethyltetrahydroanthraquinone in 50 parts of mixed solvent, add 0.3 parts of acid stabilizer, and stir at 200 rpm for 3 h at 45 °C to obtain a fully acidic working solution. The mixed solvent consists of 12 parts of heavy aromatic hydrocarbon, 6 parts of trioctyl phosphate and 4 parts of tetrabutylurea, and the acid stabilizer consists of 1 part of phytic acid, 0.6 parts of aminotrimethylphosphonic acid and 0.1 parts of silicotungstic acid.

[0035] S2. The fully acidic working fluid is introduced into a fixed-bed hydrogenation tower packed with catalyst. The hydrogenation reaction temperature is controlled at 55℃, the system pressure at 0.25MPa, the hydrogen-to-liquid volume ratio at 4:1, and the working fluid volume hourly space velocity is maintained at 8h. -1 The reaction yields a hydrogenated liquid;

[0036] S3. The hydrogenated liquid is introduced into the oxidation reactor, and pure water and oxygen are introduced at the same time. The volume ratio of pure water to hydrogenated liquid is 1:8, and the molar ratio of oxygen to hydrogen anthraquinone in hydrogenated liquid is 1.2:1. The mixture is kept at 35°C for 40 minutes to oxidize hydrogen anthraquinone into hydrogen peroxide, which is simultaneously extracted by pure water countercurrently to obtain hydrogen peroxide product.

[0037] S4. The raffinate after S3 treatment is introduced into a regeneration system independent of the main circulation and regenerated at 50°C for 2 hours. -1 The volume hourly space velocity (VHSV) passes through a regeneration bed filled with a composite regenerant. After treatment, the pH of the working solution is adjusted back to 4.0 by adding phosphoric acid. After passing the test, it is returned to the system for recycling.

[0038] The catalyst preparation step in step S2 is as follows:

[0039] A1. Mix 15 parts of phenol with 25 parts of 40wt% formaldehyde solution, adjust the pH to 8.0, and stir at 80℃ and 150rpm for 2.5h to obtain a prepolymer. Cool and set aside.

[0040] A2. Dissolve 8 parts zirconium oxychloride and 0.3 parts yttrium nitrate in 40 parts deionized water, slowly add 3 parts 86wt% phosphoric acid solution while stirring, react at 50℃ for 2 hours, and adjust the pH to 3.0 to obtain a composite sol;

[0041] A3. Mix 4 parts of prepolymer with 10 parts of composite sol, add 0.2 parts of polyethylene glycol 600, stir at 60°C for 3 hours to form a hybrid sol, and after curing and drying, calcine at 350°C for 4 hours to obtain a composite carrier.

[0042] A4. Disperse 8 parts of the composite support in 20 parts of deionized water, add 1 part of disodium ethylenediaminetetraacetate, stir at 40°C for 40 min, add 5 parts of 13wt% palladium nitrate solution, continue stirring for 3 h, then add 3 parts of formaldehyde and react at 55°C for 3 h. After filtration, washing and drying, the catalyst is obtained.

[0043] The preparation step of the composite regenerant in step S4 is as follows:

[0044] (1) 25 parts aluminum isopropoxide, 10 parts tetraethyl orthosilicate and 0.8 parts lanthanum nitrate were hydrolyzed at pH 3.0 and 60℃ for 3 h, and then 2 parts γ-aminopropyltriethoxysilane were added and the reaction continued for 3 h. After drying, the mixture was calcined at 550℃ for 5 h to obtain a composite carrier.

[0045] (2) Disperse 10 parts of composite carrier in 25 parts of deionized water, add 2 parts of 20wt% zinc nitrate solution and 0.8 parts of 15wt% tetrabutyl titanate ethanol solution dropwise at 50℃, stir and adsorb, adjust pH to neutral for in-situ precipitation, then add 3 parts of 85wt% phosphoric acid and react for 1.5h, and finally obtain composite regenerator by filtration, washing and drying.

[0046] Example 2

[0047] This embodiment provides a fully acidic fixed-bed hydrogen peroxide production process, employing the following technical solution:

[0048] S1. Dissolve 13 parts of 2-ethylanthraquinone, 3 parts of 2-pentylanthraquinone and 2 parts of 2-ethyltetrahydroanthraquinone in 51 parts of mixed solvent, add 0.4 parts of acid stabilizer, and stir at 220 rpm for 2.8 h at 48 °C to obtain a fully acidic working solution. The mixed solvent consists of 13 parts of heavy aromatic hydrocarbon, 7 parts of trioctyl phosphate and 5 parts of tetrabutylurea, and the acid stabilizer consists of 2 parts of phytic acid, 0.7 parts of aminotrimethylphosphonic acid and 0.2 parts of silicotungstic acid.

[0049] S2. The fully acidic working fluid is introduced into a fixed-bed hydrogenation tower packed with catalyst. The hydrogenation reaction temperature is controlled at 58°C, the system pressure at 0.28 MPa, the hydrogen-to-liquid volume ratio at 5:1, and the working fluid volume hourly space velocity is maintained at 9 h⁻¹. -1The reaction yields a hydrogenated liquid;

[0050] S3. The hydrogenated liquid is introduced into the oxidation reactor, and pure water and oxygen are introduced at the same time. The volume ratio of pure water to hydrogenated liquid is 1:9, and the molar ratio of oxygen to hydrogen anthraquinone in hydrogenated liquid is 1.3:1. The mixture is kept at 38°C for 37 minutes to oxidize hydrogen anthraquinone into hydrogen peroxide, which is simultaneously extracted by pure water countercurrently to obtain hydrogen peroxide product.

[0051] S4. The raffinate after S3 treatment is introduced into a regeneration system independent of the main circulation and regenerated at 58°C for 4 hours. -1 The volume hourly space velocity (VHSV) passes through a regeneration bed filled with a composite regenerant. After treatment, the pH of the working solution is adjusted back to 4.4 by adding phosphoric acid. After passing the test, it is returned to the system for recycling.

[0052] The catalyst preparation step in step S2 is as follows:

[0053] A1. Mix 16 parts of phenol with 27 parts of 38wt% formaldehyde solution, adjust the pH to 8.2, and stir at 82℃ and 160rpm for 2.4h to obtain a prepolymer. Cool and set aside.

[0054] A2. Dissolve 9 parts zirconium oxychloride and 0.4 parts yttrium nitrate in 42 parts deionized water, and slowly add 4 parts 85wt% phosphoric acid solution while stirring. React at 52℃ for 1.8h and adjust the pH to 3.2 to obtain a composite sol.

[0055] A3. Mix 5 parts of prepolymer with 11 parts of composite sol, add 0.3 parts of polyethylene glycol 600, stir at 62°C for 2.8h to form a hybrid sol, after curing and drying, calcine at 360°C for 3.8h to obtain the composite carrier;

[0056] A4. Disperse 9 parts of the composite support in 21 parts of deionized water, add 1.5 parts of disodium ethylenediaminetetraacetate, stir at 42℃ for 38 min, add 6 parts of 12wt% palladium nitrate solution, continue stirring for 2.8 h, then add 4 parts of formaldehyde and react at 58℃ for 2.8 h. After filtration, washing and drying, the catalyst is obtained.

[0057] The preparation step of the composite regenerant in step S4 is as follows:

[0058] (1) 26 parts aluminum isopropoxide, 11 parts tetraethyl orthosilicate and 0.9 parts lanthanum nitrate were hydrolyzed at pH 3.2 and 62℃ for 2.8h, and then 2.4 parts γ-aminopropyltriethoxysilane were added and the reaction continued for 2.7h. After drying, the mixture was calcined at 560℃ for 4.8h to obtain a composite carrier.

[0059] (2) Disperse 12 parts of composite carrier in 26 parts of deionized water, add 3 parts of 20wt% zinc nitrate solution and 0.9 parts of 15wt% tetrabutyl titanate ethanol solution dropwise at 51℃, stir and adsorb, adjust pH to neutral for in-situ precipitation, then add 4 parts of 84wt% phosphoric acid and react for 1.3h, and finally obtain composite regenerator by filtration, washing and drying.

[0060] Example 3

[0061] This embodiment provides a fully acidic fixed-bed hydrogen peroxide production process, employing the following technical solution:

[0062] S1. Dissolve 15 parts of 2-ethylanthraquinone, 4 parts of 2-pentylanthraquinone and 3 parts of 2-ethyltetrahydroanthraquinone in 55 parts of mixed solvent, add 0.5 parts of acid stabilizer, and stir at 300 rpm for 1 h at 55 °C to obtain a fully acidic working solution. The mixed solvent consists of 15 parts of heavy aromatic hydrocarbon, 8 parts of trioctyl phosphate and 6 parts of tetrabutylurea, and the acid stabilizer consists of 3 parts of phytic acid, 0.8 parts of aminotrimethylphosphonic acid and 0.3 parts of silicotungstic acid.

[0063] S2. The fully acidic working fluid is introduced into a fixed-bed hydrogenation tower packed with catalyst. The hydrogenation reaction temperature is controlled at 65°C, the system pressure at 0.35 MPa, the hydrogen-to-liquid volume ratio at 6:1, and the working fluid volume hourly space velocity is maintained at 12 h⁻¹. -1 The reaction yields a hydrogenated liquid;

[0064] S3. The hydrogenated liquid is introduced into the oxidation reactor, and pure water and oxygen are introduced at the same time. The volume ratio of pure water to hydrogenated liquid is 1:12, and the molar ratio of oxygen to hydrogen anthraquinone in hydrogenated liquid is 1.5:1. The mixture is kept at 45°C for 20 minutes to oxidize hydrogen anthraquinone into hydrogen peroxide, which is simultaneously extracted by pure water countercurrently to obtain hydrogen peroxide product.

[0065] S4. The raffinate after S3 treatment is introduced into a regeneration system independent of the main circulation and regenerated at 70°C for 8 hours. -1 The volume hourly space velocity (VHSV) passes through a regeneration bed filled with a composite regenerant. After treatment, the pH of the working solution is adjusted back to 5.0 by adding phosphoric acid. After passing the test, it is returned to the system for recycling.

[0066] The catalyst preparation step in step S2 is as follows:

[0067] A1. Mix 20 parts of phenol with 30 parts of 35wt% formaldehyde solution, adjust the pH to 8.5, and stir at 85℃ and 180rpm for 2 hours to obtain a prepolymer. Cool and set aside.

[0068] A2. Dissolve 12 parts zirconium oxychloride and 0.5 parts yttrium nitrate in 50 parts deionized water, slowly add 5 parts 82wt% phosphoric acid solution while stirring, react at 55℃ for 1 h, and adjust the pH to 3.5 to obtain a composite sol.

[0069] A3. Mix 8 parts of prepolymer with 15 parts of composite sol, add 0.5 parts of polyethylene glycol 600, stir at 65°C for 2 hours to form a hybrid sol, and after curing and drying, calcine at 400°C for 3 hours to obtain a composite carrier.

[0070] A4. Disperse 12 parts of the composite support in 25 parts of deionized water, add 2 parts of disodium ethylenediaminetetraacetate, stir at 45°C for 30 min, add 8 parts of 9wt% palladium nitrate solution, continue stirring for 1 h, then add 5 parts of formaldehyde and react at 60°C for 2 h. After filtration, washing and drying, the catalyst is obtained.

[0071] The preparation step of the composite regenerant in step S4 is as follows:

[0072] (1) 30 parts aluminum isopropoxide, 15 parts tetraethyl orthosilicate and 1.2 parts lanthanum nitrate were hydrolyzed at pH 3.5 and 65℃ for 1 h, and then 3 parts γ-aminopropyltriethoxysilane were added and the reaction continued for 2 h. After drying, the mixture was calcined at 600℃ for 4 h to obtain a composite carrier.

[0073] (2) Disperse 15 parts of composite carrier in 30 parts of deionized water, add 4 parts of 20wt% zinc nitrate solution and 1.2 parts of 15wt% tetrabutyl titanate ethanol solution dropwise at 55℃, stir and adsorb, adjust pH to neutral for in-situ precipitation, then add 5 parts of 80wt% phosphoric acid and react for 1h, and finally obtain composite regenerator by filtration, washing and drying.

[0074] Example 4

[0075] This embodiment provides a fully acidic fixed-bed hydrogen peroxide production process, employing the following technical solution:

[0076] S1. Dissolve 15 parts of 2-ethylanthraquinone, 3 parts of 2-pentylanthraquinone and 1 part of 2-ethyltetrahydroanthraquinone in 55 parts of mixed solvent, add 0.3 parts of acid stabilizer, and stir at 300 rpm for 1.5 h at 55 °C to obtain a fully acidic working solution. The mixed solvent consists of 14 parts of heavy aromatic hydrocarbon, 6 parts of trioctyl phosphate and 5 parts of tetrabutylurea, and the acid stabilizer consists of 1 part of phytic acid, 0.6 parts of aminotrimethylphosphonic acid and 0.1 parts of silicotungstic acid.

[0077] S2. The fully acidic working fluid is introduced into a fixed-bed hydrogenation tower packed with catalyst. The hydrogenation reaction temperature is controlled at 65℃, the system pressure at 0.30MPa, the hydrogen-to-liquid volume ratio at 5:1, and the working fluid volume hourly space velocity is maintained at 10h. -1The reaction yields a hydrogenated liquid;

[0078] S3. The hydrogenated liquid is introduced into the oxidation reactor, and pure water and oxygen are introduced at the same time. The volume ratio of pure water to hydrogenated liquid is 1:9, and the molar ratio of oxygen to hydrogen anthraquinone in hydrogenated liquid is 1.3:1. The mixture is kept at 45°C for 30 minutes to oxidize hydrogen anthraquinone into hydrogen peroxide, which is simultaneously extracted by pure water countercurrently to obtain hydrogen peroxide product.

[0079] S4. The raffinate after S3 treatment is introduced into a regeneration system independent of the main circulation and regenerated at 70°C for 5 hours. -1 The volume hourly space velocity (VHSV) passes through a regeneration bed filled with a composite regenerant. After treatment, the pH of the working solution is adjusted back to 5.0 by adding phosphoric acid. After passing the test, it is returned to the system for recycling.

[0080] The catalyst preparation step in step S2 is as follows:

[0081] A1. Mix 20 parts of phenol with 27 parts of 37wt% formaldehyde solution, adjust the pH to 8.5, and stir at 85℃ and 180rpm for 2 hours to obtain a prepolymer. Cool and set aside.

[0082] A2. Dissolve 12 parts zirconium oxychloride and 0.4 parts yttrium nitrate in 50 parts deionized water, and slowly add 5 parts 82wt% phosphoric acid solution while stirring. React at 55℃ for 1.5h and adjust the pH to 3.5 to obtain a composite sol.

[0083] A3. Mix 8 parts of prepolymer with 15 parts of composite sol, add 0.5 parts of polyethylene glycol 600, stir at 65°C for 2 hours to form a hybrid sol, and after curing and drying, calcine at 350°C for 3.2 hours to obtain a composite carrier.

[0084] A4. Disperse 12 parts of composite support in 25 parts of deionized water, add 1 part of disodium ethylenediaminetetraacetate, stir at 45℃ for 35 min, add 8 parts of 10wt% palladium nitrate solution, continue stirring for 1.8 h, then add 4 parts of formaldehyde and react at 60℃ for 2.5 h. After filtration, washing and drying, the catalyst is obtained.

[0085] The preparation step of the composite regenerant in step S4 is as follows:

[0086] (1) 30 parts aluminum isopropoxide, 15 parts tetraethyl orthosilicate and 1.2 parts lanthanum nitrate were hydrolyzed at pH 3.5 and 65℃ for 1.5 h, and then 3 parts γ-aminopropyltriethoxysilane were added and the reaction continued for 2.5 h. After drying, the mixture was calcined at 550℃ for 4.5 h to obtain a composite carrier.

[0087] (2) Disperse 15 parts of composite carrier in 30 parts of deionized water, add 4 parts of 20wt% zinc nitrate solution and 1.2 parts of 15wt% tetrabutyl titanate ethanol solution dropwise at 55℃, stir and adsorb, adjust pH to neutral for in-situ precipitation, then add 5 parts of 80wt% phosphoric acid and react for 1.5h, and finally obtain composite regenerator by filtration, washing and drying.

[0088] Comparative Example 1

[0089] A fully acidic fixed-bed hydrogen peroxide production process differs from Example 4 in that no acidic stabilizer is added. In step S1, only the composite anthraquinone is dissolved in the mixed solvent, without the addition of phytic acid, aminotrimethylphosphonic acid, and silicotungstic acid. Other conditions are the same as in Example 4.

[0090] Comparative Example 2

[0091] A fully acidic fixed-bed hydrogen peroxide production process differs from Example 4 in that the catalyst support is different. Specifically, in the catalyst preparation, a conventional γ-alumina support is used instead of a hybrid composite support. Specifically, steps A1-A3 are omitted, and γ-alumina is directly used as the support for the palladium loading operation in step A4. Other conditions are the same as in Example 4.

[0092] Comparative Example 3

[0093] A fully acidic fixed-bed hydrogen peroxide production process differs from Example 4 in that step A1 is omitted in the catalyst preparation. Instead, the composite sol obtained in step A2 is directly mixed with polyethylene glycol 600 to form a hybrid sol, which is then cured, dried, and calcined to obtain a composite carrier. The active component is then loaded in step A4. Other conditions are the same as in Example 4.

[0094] Comparative Example 4

[0095] A fully acidic fixed-bed hydrogen peroxide production process differs from Example 4 in that step A2 is omitted in the catalyst preparation. Instead, the phenolic resin prepolymer obtained in step A1 is directly mixed with polyethylene glycol 600 to form a sol, which is then cured, dried, and calcined to obtain a carrier. The active component is then loaded in step A4. Other conditions are the same as in Example 4.

[0096] Comparative Example 5

[0097] A fully acidic fixed-bed hydrogen peroxide production process differs from Example 4 in that disodium ethylenediaminetetraacetate is omitted in the catalyst preparation. That is, in step A4, the composite carrier is directly dispersed and then added to the palladium nitrate solution without adding disodium ethylenediaminetetraacetate as a chelating agent. Other conditions are exactly the same as in Example 4.

[0098] Comparative Example 6

[0099] A fully acidic fixed-bed hydrogen peroxide production process differs from Example 4 in that zinc nitrate solution is not added in the preparation of the composite regenerator. That is, in step (2), only tetrabutyl titanate ethanol solution is added dropwise, and 20wt% zinc nitrate solution is not added. Other conditions are the same as in Example 4.

[0100] Performance testing

[0101] The performance of the fully acidic fixed-bed hydrogen peroxide production processes in Examples 1-4 and Comparative Examples 1-6 was tested, and the test results are shown in Table 1.

[0102] Table 1

[0103] Test Project Hydrogenation efficiency g / L Oxidation efficiency (g / L) hydrogen peroxide concentration % Degradation content (g / L) Example 1 9.32 9.25 36.9 0.075 Example 2 9.62 9.41 37.2 0.072 Example 3 9.92 9.67 37.5 0.068 Example 4 10.12 9.85 37.8 0.065 Comparative Example 1 8.27 7.94 36.4 0.091 Comparative Example 2 5.53 4.63 33.6 0.157 Comparative Example 3 7.62 6.86 35.0 0.102 Comparative Example 4 6.45 5.71 34.4 0.124 Comparative Example 5 7.92 7.47 35.9 0.095 Comparative Example 6 9.30 9.22 36.8 0.105

[0104] Of Examples 1-4, Example 4 achieved the best performance, with a hydrogenation efficiency of 10.12 g / L, an oxidation efficiency of 9.85 g / L, a hydrogen peroxide concentration of 37.8%, and a degradation product content as low as 0.065 g / L. The performance of the comparative examples was generally lower than that of the examples. Comparative Example 1, due to the absence of an acid stabilizer, was easily disturbed during circulation, resulting in an increased degradation product content of 0.091 g / L. Comparative Example 2 used a traditional γ-alumina support, and the catalyst's tolerance to acidic environments was insufficient, leading to a significant decrease in hydrogenation efficiency to 5.53 g / L. Comparative Examples 3 and 4, due to incomplete hybrid structure of the catalyst support and the lack of a composite sol, respectively, affected the distribution of active sites and acid stability, resulting in a significant decrease in oxidation efficiency and hydrogen peroxide concentration. Comparative Example 5, due to the omission of a chelating agent, resulted in uneven dispersion of the palladium active component and weakened catalytic selectivity. Although Comparative Example 6 had a high hydrogenation efficiency, the incomplete function of the regenerator resulted in insufficient degradation product control.

[0105] The above description is merely an example and illustration of the present invention. Those skilled in the art can make various modifications or additions to the specific embodiments described, or use similar methods to replace them, as long as they do not deviate from the invention or exceed the scope defined in the claims, all of which should fall within the protection scope of the present invention.

Claims

1. A fully acidic fixed-bed hydrogen peroxide production process, characterized in that, Includes the following steps: S1. Dissolve 2-ethylanthraquinone, 2-pentylanthraquinone and 2-ethyltetrahydroanthraquinone in a mixed solvent, add an acidic stabilizer, and stir to obtain a fully acidic working solution; S2. The fully acidic working fluid is passed into a fixed-bed hydrogenation tower filled with catalyst, and hydrogenated liquid is obtained after the reaction. S3. The hydrogenated liquid is introduced into the oxidation reactor, and pure water and oxygen are introduced at the same time, so that the anthraquinone is oxidized to generate hydrogen peroxide, which is simultaneously extracted by pure water in a countercurrent manner to obtain hydrogen peroxide product. S4. The raffinate after S3 is introduced into a regeneration system independent of the main circulation. After passing through a regeneration bed filled with a composite regenerant, the pH value of the working solution is adjusted by adding phosphoric acid. After passing the test, it is returned to the system for recycling. The acid stabilizer is composed of 1-3 parts phytic acid, 0.6-0.8 parts aminotrimethylphosphonic acid and 0.1-0.3 parts silicotungstic acid; The catalyst preparation steps in step S2 are as follows: A1. Mix phenol and formaldehyde solution, adjust pH and stir to react to obtain prepolymer, cool and set aside. A2. Dissolve zirconium oxychloride and yttrium nitrate in deionized water, and slowly add phosphoric acid solution while stirring. After the reaction, a composite sol is obtained. A3. Mix the prepolymer with the composite sol, add polyethylene glycol 600, stir to form a hybrid sol, and after curing and drying, calcin to obtain the composite carrier; A4. Disperse the composite support in deionized water, add disodium ethylenediaminetetraacetate, stir, add palladium nitrate solution, continue stirring, then add formaldehyde to react, and obtain the catalyst after filtration, washing, and drying.

2. The all-acid fixed-bed hydrogen peroxide production process according to claim 1, characterized in that, In step S1, the ingredients are 12-15 parts by weight of 2-ethylanthraquinone, 2-4 parts of 2-pentylanthraquinone, 1-3 parts of 2-ethyltetrahydroanthraquinone, 50-55 parts of mixed solvent, and 0.3-0.5 parts of acid stabilizer.

3. The fully acidic fixed-bed hydrogen peroxide production process according to claim 1, characterized in that, In step S1, the mixed solvent consists of 12-15 parts of heavy aromatic hydrocarbons, 6-8 parts of trioctyl phosphate, and 4-6 parts of tetrabutylurea.

4. The fully acidic fixed-bed hydrogen peroxide production process according to claim 1, characterized in that, In step S2, the hydrogenation reaction temperature is 55-65℃, the system pressure is 0.25-0.35MPa, the volume ratio of hydrogen to working fluid is 4-6:1, and the volume hourly space velocity (VHSV) of the working fluid is 8-12 h⁻¹. -1 .

5. The all-acid fixed-bed hydrogen peroxide production process according to claim 1, characterized in that, Step A1 consists of 15-20 parts by weight of phenol and 25-30 parts by weight of 35-40 wt% formaldehyde solution, while step A2 consists of 8-12 parts by weight of zirconium oxychloride, 0.3-0.5 parts by weight of yttrium nitrate, 40-50 parts by weight of deionized water and 3-5 parts by weight of 82-86 wt% phosphoric acid solution.

6. The fully acidic fixed-bed hydrogen peroxide production process according to claim 1, characterized in that, By weight, step A3 comprises 4-8 parts prepolymer, 10-15 parts composite sol, and 0.2-0.5 parts polyethylene glycol 600, and step A4 comprises 8-12 parts composite carrier, 20-25 parts deionized water, 1-2 parts disodium ethylenediaminetetraacetate, 5-8 parts 9-13 wt% palladium nitrate solution, and 3-5 parts formaldehyde.

7. The all-acid fixed-bed hydrogen peroxide production process according to claim 1, characterized in that, The preparation steps of the composite regenerator in step S4 are as follows: (1) After hydrolyzing aluminum isopropoxide, tetraethyl orthosilicate and lanthanum nitrate, γ-aminopropyltriethoxysilane was added to continue the reaction, and the composite carrier was obtained by drying and calcining. (2) The composite carrier is dispersed in deionized water, and zinc nitrate solution and tetrabutyl titanate ethanol solution are added dropwise in sequence. After stirring and adsorption, the pH is adjusted to neutral for in-situ precipitation. Then, phosphoric acid is added to react. Finally, the composite regenerator is obtained by filtration, washing and drying.

8. The all-acid fixed-bed hydrogen peroxide production process according to claim 7, characterized in that, In step (1), the ingredients are 25-30 parts by weight of aluminum isopropoxide, 10-15 parts of tetraethyl orthosilicate, 0.8-1.2 parts of lanthanum nitrate and 2-3 parts of γ-aminopropyltriethoxysilane.

9. The all-acid fixed-bed hydrogen peroxide production process according to claim 7, characterized in that, In step (2), the components by weight are 10-15 parts of composite carrier, 25-30 parts of deionized water, 2-4 parts of 20wt% zinc nitrate solution, 0.8-1.2 parts of 15wt% tetrabutyl titanate ethanol solution and 3-5 parts of 80-85wt% phosphoric acid.