Preparation method, application and regeneration method of nitro reduction catalyst
By using activated carbon, iron trichloride and cobalt chloride to prepare catalysts and use them in combination with hydrazine hydrate, catalytic reduction of nitro groups instead of iron powder reduction process, the iron sludge problem generated by iron powder reduction in traditional processes is solved, and the 100% reuse of the catalyst and the yield of reduction reactions is improved, which significantly improves economic benefits.
Patent Information
- Application Number
- CN202510297942.9
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-03-13
- Publication Date
- 2025-06-06
Smart Images
Figure CN120094614A_ABST
Abstract
Description
Technical Field
[0001] The invention relates to the technical field of chemical production, and in particular to a preparation method, application and regeneration method of a nitro reduction catalyst. Background Art
[0002] Sulfonamide compounds are widely used in the pharmaceutical, dye and other industries. They can be used as raw materials for sulfonamide anti-inflammatory drugs, used in the synthesis of pharmaceutical products and antidiarrheal drugs. They can also be used as raw materials for the synthesis of acid dyes and reactive dyes. Sulfonamide compounds are usually generated by nitro reduction catalyzed by a catalyst.
[0003] The traditional nitro reduction process uses iron powder reduction, but the amount of iron powder used in the reduction process is large, usually 20%-30% of the nitro compound, and a large amount of difficult-to-handle iron sludge will be produced after the reaction. The iron sludge produced in the iron powder reduction process contains a large amount of toxic aniline compounds, which is a hazardous solid waste and cannot be reused. For this reason, we proposed a preparation method, application and regeneration method of a nitro reduction catalyst to solve the above problems. Summary of the invention
[0004] The present application provides a preparation method, application and regeneration method of a nitro reduction catalyst, which solves the problems of a traditional iron powder reduction process, such as high iron sludge content, difficulty in treatment and high treatment cost.
[0005] The present application provides a method for preparing a nitro reduction catalyst, comprising the following steps: The powdered activated carbon and pure water are stirred and slurried in a ratio of 1:8 (by weight) to form an activated carbon slurry; Prepare a 20%-30% solution by mixing ferric chloride and cobalt chloride in a ratio of 1:0.02-0.06 (weight ratio); Add the solution dropwise into the activated carbon slurry with stirring; Adjusting the pH of the activated carbon slurry to 6.8-7.0 by sodium hydroxide solution; Filtering to obtain a filter cake, and washing the filter cake with pure water; The filter cake was dried to obtain a catalyst.
[0006] Preferably, the preparation of the catalyst is carried out at a temperature of 20-60°C.
[0007] Preferably, the filter cake is dried at a temperature of 80-85°C.
[0008] Preferably, the total mass of the ferric chloride and the cobalt chloride is 3%-8% of the mass of the activated carbon.
[0009] The present application also discloses an application of a nitro reduction catalyst, characterized in that it comprises the following steps: Add 2%-5% (mass ratio) of nitro compound catalyst to the nitro compound solution and stir evenly; Add hydrazine hydrate dropwise and stir evenly; The reaction is terminated when the nitro content is less than 0.5%; The catalyst is filtered and reused.
[0010] Preferably, the catalyst can be reused 8-10 times.
[0011] Preferably, the catalyst is used for the synthesis of 2-aminophenol-4-sulfonic acid, o-chloroaniline-5-sulfonic acid or aniline-2,5-disulfonic acid.
[0012] Preferably, the reaction is carried out at 20-80°C.
[0013] Preferably, the mass of the hydrazine hydrate is 15%-35% of the mass of the nitro substance.
[0014] The present application also discloses a method for regenerating a nitro reduction catalyst, which is characterized by comprising the following steps: adding hydrochloric acid to the catalyst to remove iron and cobalt adsorbed on the activated carbon, filtering to obtain a filtrate and activated carbon, wherein the activated carbon is recycled; Adding a liquid alkali solution to the filtrate to adjust the pH to 7.0-7.5, wherein iron ions and cobalt ions are precipitated; The filtrate is filtered, the solid matter is recycled, and the filtrate is sodium chloride wastewater, which is sold as a resource after evaporation.
[0015] It can be seen from the above technical scheme that the present application provides a preparation method, application and regeneration method of a nitro reduction catalyst. The present application utilizes hydrazine hydrate and the prepared catalyst to catalyze the reduction of nitro to replace the iron powder reduction process. The catalyst is first prepared by activated carbon, ferric chloride and cobalt chloride, and then the prepared catalyst and hydrazine hydrate are used together, which not only improves the conversion rate of the reduction reaction. After the reaction is completed, the catalyst can be regenerated and reused after being used 8-10 times. The catalyst of the entire process can be 100% reused. The use of hydrazine hydrate and an efficient, inexpensive and reusable iron-based composite carbon catalyst perfectly solves the problem of the iron powder reduction process.
[0016] Compared with the prior art, the present invention has the following beneficial effects: The present application solves the problem that the iron powder reduction process has a large dosage, cannot be recycled and contains a large amount of organic matter that is difficult to handle. The catalyst of the present application not only has a small dosage, but the catalyst can also be recycled and reused. In the nitro reduction process, the catalyst can be 100% recycled, and the reduction reaction yield is further improved, with significant economic benefits. BRIEF DESCRIPTION OF THE DRAWINGS
[0017] In order to more clearly illustrate the technical solution of the present application, the following is a brief introduction to the drawings required for use in the implementation cases. Obviously, for ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.
[0018] Figure 1 This is the application reaction equation of a nitro reduction catalyst proposed by the present invention; DETAILED DESCRIPTION
[0019] In order to enable those skilled in the art to better understand the technical solutions in the present application, the technical solutions in the embodiments of the present application will be clearly and completely described below in conjunction with the accompanying drawings.
[0020] The traditional nitro reduction process uses iron powder reduction, but the iron powder reduction process will produce a large amount of difficult-to-handle iron sludge, and the iron sludge produced in the iron powder reduction process contains a large amount of toxic aniline compounds, which is a hazardous solid waste. The present application route has been fully compared through multiple experiments and concluded that the use of hydrazine hydrate catalytic reduction can greatly improve the conversion rate of the reduction reaction, and the solid hazardous waste and waste mother liquor produced will be less, which can better solve the pollution problem and moderately reduce costs.
[0021] A method for preparing a nitro reduction catalyst comprises the following steps: The powdered activated carbon and pure water are mixed and beaten into activated carbon slurry at a weight ratio of 1:8. During the preparation process, the activated carbon slurry is continuously stirred and heated to 20-60°C. Prepare a 20%-30% solution by mixing ferric chloride and cobalt chloride in a ratio of 1:0.02-0.06 (weight ratio); The solution is added dropwise to the activated carbon slurry with stirring, and the mixture is stirred during the addition process. The mixture is stirred for 1 hour and the temperature is kept at 20-60° C. The total mass of the ferric chloride and the cobalt chloride in the present application is 3%-8% of the mass of the activated carbon. After the solution is added, the pH of the activated carbon slurry is adjusted to 6.8-7.0 by 30% sodium hydroxide solution, and then the temperature is controlled at 20-60°C and stirred for 2 hours; The filter cake is obtained by suction filtration, and the filter cake is washed with pure water for three times; The filter cake is dried to obtain a catalyst. The filter cake is dried at a temperature of 80-85° C. to complete the production of the catalyst.
[0022] An application of a nitro reduction catalyst, characterized in that it comprises the following steps: Add 2%-5% (mass ratio) of nitro compound catalyst to the nitro compound solution and stir evenly; The nitro solution is heated to 20-80°C, hydrazine hydrate is added dropwise and stirred evenly, and after the hydrazine hydrate is added dropwise, the temperature is kept for 2 hours and a sample is taken for testing. In this application, the mass of hydrazine hydrate is 15%-35% of the mass of the nitro substance; The reaction is terminated when the nitro content is less than 0.5%. Figure 1 As shown; The catalyst is filtered and reused, and the end point is reached after filtering. The filter cake is the recovered catalyst, and the filtrate is the reduced product. The product is obtained after crystallization and filtration. The catalyst can be reused for 8-10 times. The reaction principle of this application is as follows Figure 1 shown.
[0023] A method for regenerating a nitro reduction catalyst comprises the following steps: adding hydrochloric acid to the catalyst to remove iron and cobalt adsorbed on the activated carbon, filtering to obtain a filtrate and activated carbon, wherein the activated carbon is recycled; Adding a liquid alkali solution to the filtrate to adjust the pH to 7.0-7.5, wherein iron ions and cobalt ions are precipitated and are again made into ferric chloride and cobalt chloride for reuse; The filtrate is filtered, the solid matter is recycled, and the filtrate is sodium chloride wastewater, which is sold as a resource after evaporation.
[0024] Example 1 888.89 kg of sodium sulfite was added to 1642.38 kg of sodium sulfonate after hydrolysis. After the reaction, the conversion rate of sodium sulfonate was 98%. Then 52.5 kg of catalyst was added, the temperature was raised to 60 ° C, and 328.50 kg of hydrazine hydrate was slowly added dropwise. After the addition was completed, the temperature was kept for 2 hours and samples were taken for detection. The nitro content was less than 0.5%, which was the end point of the reaction. Then 315.00 kg of hydrochloric acid was added for acidification. After concentration and centrifugation, 1522.45 kg of aniline-2,5-disulfonic acid product was obtained, and the conversion rate was 92%.
[0025] Example 2 After hydrolyzing 1642.38 kg of sodium sulfonate, 52.5 kg of catalyst was added, the temperature was raised to 60°C, and 335.20 kg of hydrazine hydrate was slowly added dropwise. After the addition was completed, the temperature was kept for 2 hours and samples were taken for detection. The reaction end point was when the nitro content was less than 0.5%. After acidification with 256.80 kg of hydrochloric acid, 1134.69 kg of o-chloroaniline-5-sulfonic acid was obtained by concentration and centrifugation, and the conversion rate was 90%.
[0026] Example 3 1642.38 kg of sodium sulfonate was added to 533.30 kg of sodium hydroxide for hydrolysis with a conversion rate of 100%. Then 52.5 kg of catalyst was added, the temperature was raised to 60°C, and 523.75 kg of hydrazine hydrate was slowly added dropwise. After the addition was completed, the temperature was kept for 2 hours and samples were taken for detection. The reaction end point was when the nitro content was lower than 0.5%. Then 511.17 kg of hydrochloric acid was added for acidification to obtain 1020.79 kg of 2-aminophenol-4-sulfonic acid with a conversion rate of 92%.
[0027] It can be seen from the above technical scheme that the present application utilizes hydrazine hydrate and the prepared catalyst to catalytically reduce the nitro-substituted iron powder reduction process. First, the catalyst is prepared by activated carbon, ferric chloride and cobalt chloride, and then the prepared catalyst and hydrazine hydrate are used together, which not only improves the conversion rate of the reduction reaction, but also after the reaction is completed, the catalyst can be regenerated and reused after being used 8-10 times. The catalyst of the entire process can be 100% reused. The use of hydrazine hydrate and an efficient, cheap and reusable iron-based composite carbon catalyst perfectly solves the problem of the iron powder reduction process, and the average yield of the reduction is increased from 70-75% of the iron powder reduction to 85-90%, and the economic benefit is very significant.
[0028] Those skilled in the art will readily appreciate other embodiments of the present application after considering the specification and practicing the application disclosed herein. The present application is intended to cover any variations, uses or adaptations of the present application, which follow the general principles of the present application and include common knowledge or customary techniques in the art that are not disclosed in the present application. The specification and examples are intended to be exemplary only, and the true scope of the present application is indicated by the claims.
[0029] It should be understood that the present application is not limited to the precise structure described above and shown in the drawings, and various modifications and changes can be made without departing from its scope. The above-described embodiments of the present application do not constitute a limitation on the scope of protection of the present application.
Claims
1. A method for preparing a nitro reduction catalyst, characterized in that: The following steps are involved: The powdered activated carbon and pure water are stirred and slurried in a ratio of 1:8 (by weight) to form an activated carbon slurry; Prepare a 20%-30% solution by mixing ferric chloride and cobalt chloride in a ratio of 1:0.02-0.06 (weight ratio); Add the solution dropwise into the activated carbon slurry with stirring; Adjusting the pH of the activated carbon slurry to 6.8-7.0 by sodium hydroxide solution; Filtering to obtain a filter cake, and washing the filter cake with pure water; The filter cake was dried to obtain a catalyst.
2. The method for preparing a nitro reduction catalyst according to claim 1, characterized in that: The preparation of the catalyst is carried out at a temperature of 20-60°C.
3. The method for preparing a nitro reduction catalyst according to claim 1, characterized in that: The filter cake was dried at a temperature of 80-85°C.
4. The method for preparing a nitro reduction catalyst according to claim 1, characterized in that: The total mass of the ferric chloride and the cobalt chloride is 3%-8% of the mass of the activated carbon.
5. An application of a nitro reduction catalyst, characterized in that: The following steps are involved: Add 2%-5% (mass ratio) of nitro compound catalyst to the nitro compound solution and stir evenly; Add hydrazine hydrate dropwise and stir evenly; The reaction is terminated when the nitro content is less than 0.5%; The catalyst is filtered and reused.
6. The use of a nitro reduction catalyst according to claim 5, characterized in that: The catalyst can be reused 8-10 times.
7. The use of a nitro reduction catalyst according to claim 5, characterized in that: The catalyst is used for the synthesis of 2-aminophenol-4-sulfonic acid, o-chloroaniline-5-sulfonic acid or aniline-2,5-disulfonic acid.
8. The use of a nitro reduction catalyst according to claim 5, characterized in that: The reaction is carried out at 20-80°C.
9. The use of a nitro reduction catalyst according to claim 5, characterized in that: The mass of the hydrazine hydrate is 15%-35% of the mass of the nitro substance.
10. A method for regenerating a nitro reduction catalyst, characterized in that: The following steps are involved: adding hydrochloric acid to the catalyst to remove iron and cobalt adsorbed on the activated carbon, filtering to obtain a filtrate and activated carbon, wherein the activated carbon is recycled; Adding a liquid alkali solution to the filtrate to adjust the pH to 7.0-7.5, wherein iron ions and cobalt ions are precipitated; The filtrate is filtered, the solid matter is recycled, and the filtrate is sodium chloride wastewater, which is sold as a resource after evaporation.