Method for treating and recovering waste sulfuric acid solution from adamantane ketone production

Abstract

The present application relates to a treatment and recovery method of 2-adamantanone production waste sulfuric acid solution, which comprises the following steps: preparing a paste slurry composed of inorganic mineral bentonite, alkane organic solvent and dilute sulfuric acid solution, mixing the paste slurry into the waste sulfuric acid solution, removing the suspended polymer colloid in the waste sulfuric acid solution by condensation and evaporation and hydrogen peroxide oxidation treatment, and removing the sulfur dioxide in the waste sulfuric acid solution by condensation and evaporation and hydrogen peroxide oxidation treatment, so as to obtain a relatively pure dilute sulfuric acid solution which can be directly used. The present application has simple operation and low treatment cost, and the recovered dilute sulfuric acid solution can be directly used.

Description

Technical Field

[0001] This invention relates to the field of chemical engineering technology, and in particular to a method for treating and recovering waste sulfuric acid solution generated during the production of 2-adamantanone. Background Technology

[0002] 2-Adamantane, as a raw material for preparing various other 2-substituted adamantane derivatives, is an important intermediate in the production of many pharmaceuticals. Currently, the industrial production of 2-adamantane both domestically and internationally uses adamantane or 1-adamantane alcohol as starting materials, obtained through direct oxidation with concentrated sulfuric acid. Adamantane or 1-adamantane alcohol reacts with sulfuric acid to produce the intermediate 2-adamantane alcohol sulfate. After the reaction is terminated, it undergoes hydrolysis in water, releasing the target product, 2-adamantane. Due to the presence of concentrated sulfuric acid and heating conditions, the polymerization of the intermediate 2-adamantane alcohol sulfate inevitably occurs, forming a polymeric gel. Traditional oxidation processes typically only convert 40%–50% of the starting material into the target product, while the remaining 50%–60% becomes a polymeric gel due to side reactions. Even with improved oxidation processes, at least 20%–30% of the raw material is usually converted into a polymeric gel due to side reactions. The oxidation process of 2-adamantanone requires dilution of the reactants with water at the end of the reaction to eliminate the oxidizing properties of concentrated sulfuric acid. Simultaneously, the intermediate 2-adamantanol sulfate is hydrolyzed, releasing the target product, 2-adamantanone. The reaction mixture after water dilution mainly consists of dilute sulfuric acid, typically with a sulfuric acid content of 30%–40%. The target product, 2-adamantanone, floats as precipitated crystals on the surface of the dilute sulfuric acid solution. A large amount of polymeric gum produced by the side reactions is dispersed in the dilute sulfuric acid solution as a relatively stable suspension. Furthermore, the dilute sulfuric acid solution also contains a significant amount of sulfur dioxide, a product of the oxidation reaction.

[0003] The production of 2-adamantanone typically involves a large amount of concentrated sulfuric acid. After hydrolysis, dilution, and separation of the target product, 2-adamantanone, a significant amount of waste dilute sulfuric acid is left behind. Typically, 30 to 50 tons of waste dilute sulfuric acid are generated for every ton of 2-adamantanone produced. This waste sulfuric acid contains a large amount of suspended polymeric colloids and a significant amount of sulfur dioxide, giving it a blackish-gray slurry-like appearance and emitting a foul sulfur dioxide odor that pollutes the environment. The usual method for treating this waste sulfuric acid is to neutralize it with a strong inorganic alkali (such as sodium hydroxide). In neutral or weakly alkaline aqueous solutions, the polymeric colloids easily coagulate and separate. The sulfate and sulfite solutions remaining after removing the polymeric colloids are then evaporated and concentrated. However, this method consumes a large amount of alkali and requires a large volume of water to evaporate. Furthermore, the large amount of sulfate and sulfite mixture precipitated after evaporation requires further treatment, resulting in high processing costs.

[0004] People have also realized that the best way to directly process and recycle waste sulfuric acid is to do so. However, because waste sulfuric acid contains a large amount of suspended polymeric colloids, and these polymeric colloids are in the form of fine suspended particles in dilute sulfuric acid with good suspension stability, they cannot be removed by filtration. It is also difficult to effectively adsorb and coagulate them with flocculants, activated carbon, etc. It is very difficult to process waste sulfuric acid into pure dilute sulfuric acid. This is a technical problem that urgently needs to be solved. Summary of the Invention

[0005] The purpose of this invention is to provide a method for treating and recycling waste sulfuric acid from 2-adamantanone production, which aims to effectively remove suspended polymeric colloids and sulfur dioxide from the waste sulfuric acid from 2-adamantanone production and prepare it into pure dilute sulfuric acid for recycling.

[0006] The present invention provides a solution for the treatment and recovery of waste sulfuric acid solution containing suspended polymeric substances and sulfur dioxide generated during the production of 2-adamantanone, as follows:

[0007] 1. Preparation of a special adsorbent-coagulant paste:

[0008] First, mix and soak the bentonite with an organic solvent. After it swells, vigorously mix it with dilute sulfuric acid to form a paste.

[0009] The bentonite used here should be inorganic mineral bentonite that is insoluble in water but can swell several times its original size when exposed to water, and can also be well wetted and swelled with organic solvents. Activated clay and natural bleaching clay, which have poor wettability and swelling properties in water and organic solvents, should not be used. Organic bentonite, which has too strong swelling properties in water and organic solvents and forms a gel, should also not be used.

[0010] The organic solvents used here are alkane solvents, with petroleum ether (60℃~120℃ distillation range), solvent oil (60℃~120℃ distillation range), n-hexane, n-heptane, and n-octane being the preferred choices.

[0011] The dilute sulfuric acid used here has a content of 55% to 65%. In actual operation, dilute sulfuric acid prepared according to the method of this invention can be used directly.

[0012] Bentonite: Organic solvent: Dilute sulfuric acid = 2:(1-2):15 (mass ratio)

[0013] The operating temperature is room temperature (20℃~40℃ is acceptable).

[0014] 2. Adsorption and coagulation of suspended polymeric colloids in waste sulfuric acid solution:

[0015] Add the paste prepared in step 1 above to the waste sulfuric acid solution to be treated, and stir vigorously at 40℃~50℃ for 20~30 minutes. Stop stirring, let it stand for more than 6 hours, and allow it to cool naturally to room temperature (15℃~30℃). Wait for the solid materials in the waste sulfuric acid solution to fully float to the surface and agglomerate into coarse particles.

[0016] Here, the ratio of waste sulfuric acid liquid to paste is 100:2 to 8 (by mass). The specific amount of paste added depends on the content of suspended polymers in the waste sulfuric acid liquid, and should be sufficient to fully adsorb and aggregate the suspended polymers in the waste sulfuric acid liquid.

[0017] 3. Separation and removal of agglomerated solids:

[0018] Remove the condensed solid material from the surface of the waste sulfuric acid solution, and dispose of the removed solid residue separately.

[0019] 4. Further adsorption and removal of fine aggregated particles still suspended in the waste sulfuric acid solution:

[0020] Add activated carbon powder to the waste sulfuric acid solution after removing the floating slag, stir at 50℃~60℃ for about 1 hour, cool down to 20℃~30℃, and then filter the material to remove solid material.

[0021] Here, the ratio of waste sulfuric acid solution to activated carbon powder is 100:0.2-0.5 (mass ratio).

[0022] 5. Evaporation and concentration, simultaneously removing most of the sulfur dioxide:

[0023] The waste sulfuric acid solution after removing the activated carbon solids is evaporated under reduced pressure. Most of the sulfur dioxide in the waste sulfuric acid solution is distilled off with the water vapor and collected for further disposal. Evaporation and concentration are stopped when the sulfuric acid content reaches about 60%. The temperature is then lowered to 40℃~50℃.

[0024] 6. Remove residual sulfur dioxide:

[0025] Add an appropriate amount of hydrogen peroxide dropwise to the concentrated dilute sulfuric acid solution to oxidize and remove residual sulfur dioxide. The amount of hydrogen peroxide added should be sufficient to completely oxidize the residual sulfur dioxide.

[0026] The reaction operation temperature is 40℃~50℃.

[0027] After the reaction is complete, the dilute sulfuric acid solution is cooled to room temperature and packaged for other uses.

[0028] The researchers in this application observed through multiple experiments that neither adding bentonite alone nor organic solvent alone to waste sulfuric acid solution for mixing, nor adding bentonite and organic solvent separately to waste sulfuric acid solution for mixing, could effectively adsorb and coagulate suspended polymeric colloids in the waste sulfuric acid solution. If only an expanded paste of bentonite and organic solvent was prepared, the dispersion effect after adding it to waste sulfuric acid solution was not good, requiring a large amount of paste to achieve a limited adsorption and coagulation effect on polymeric colloids. If only an expanded paste of bentonite and dilute sulfuric acid solution was prepared, it was almost ineffective in adsorbing and coagulating polymeric colloids. Only by preparing an expanded paste of bentonite, organic solvent, and dilute sulfuric acid solution in sequence according to the method of this application, and then adding it to waste sulfuric acid solution for mixing, can a good adsorption and coagulation effect on suspended polymeric colloids in waste sulfuric acid solution be achieved while using less paste. Furthermore, even using these three materials but changing the order of adding bentonite, organic solvent, and dilute sulfuric acid could not produce a paste with good adsorption and coagulation effects.

[0029] The researchers in this application also observed through experiments that the paste prepared using inorganic mineral bentonite, which is insoluble in water but expands several times its original size upon contact with water and also expands well with organic solvents, exhibits good dispersion after the addition of waste sulfuric acid solution, excellent adsorption and coagulation effects on suspended polymers, and the coagulated residue floating on the acid surface is easy to remove and separate. However, if activated clay and natural bleaching clay, which have poor wetting and swelling properties in water and organic solvents, are used, it is difficult to prepare a good paste, and the dispersion effect after adding waste sulfuric acid solution is also poor, as is the adsorption and coagulation effect on suspended polymers. If organic bentonite, which has excessive swelling properties in water and organic solvents, is used, it is easy to prepare a gel material (rather than a paste). While it disperses well after adding waste sulfuric acid solution and exhibits good adsorption and coagulation effects on suspended polymers, it is difficult to form easily removable and separable agglomerated particles. Instead, it forms a viscous film-like material that floats on the acid surface and adheres to the container. During removal, it easily adheres to the handling tools, causing inconvenience in separating the coagulated residue.

[0030] The researchers in this application conducted experiments on the preparation of pastes using various types of organic solvents. By comparing and selecting solvents based on minimizing their usage and maximizing their adsorption and coagulation effects on suspended polymers, they observed that alkane-based organic solvents were the most effective. Considering raw material sources and costs, petroleum ether, solvent oil, n-hexane, n-heptane, and n-octane with a distillation range of 60℃–120℃ were preferred.

[0031] Based on numerous experimental observations, the researchers of this application determined that the special paste prepared according to the method of this application can be well dispersed and come into contact with the suspended polymer after being added to waste sulfuric acid solution. The suspended polymer formed by the oxidative polymerization of adamantane has strong oleophilic and hydrophobic properties, and therefore easily adsorbs and aggregates with bentonite that has been soaked and swelled in organic solvents.

[0032] The experiment also observed that the special paste prepared in this application not only has a good adsorption and coagulation effect on suspended colloids in waste sulfuric acid solution, but also has a certain adsorption and removal effect on sulfur dioxide in waste sulfuric acid solution.

[0033] After the floating sludge is removed by adsorption and coagulation of a special paste, the small amount of fine sludge remaining in the acid solution is further separated by adsorption of activated carbon powder. This process can effectively remove suspended polymeric colloids from the waste sulfuric acid solution, resulting in a dilute sulfuric acid solution free of suspended polymeric colloids.

[0034] By reducing pressure and evaporating, the sulfuric acid solution is concentrated and most of the residual sulfur dioxide in the acid solution is volatilized and removed.

[0035] Finally, the small amount of sulfur dioxide remaining in the acid solution is oxidized to sulfur trioxide by adding an appropriate amount of hydrogen peroxide (sulfur trioxide combines with water to form sulfuric acid), thus obtaining a relatively pure dilute sulfuric acid solution.

[0036] The method described in this application is effective in treating waste sulfuric acid liquid from the production of 2-adamantanone and is relatively simple to operate. It has already been put into production at the company where the researchers of this application work.

[0037] Technical effects:

[0038] The technical solution of the present invention can achieve the following effects:

[0039] 1. It can effectively remove suspended polymeric colloids and sulfur dioxide from the waste sulfuric acid solution produced in the production of 2-adamantanone, and obtain a relatively pure dilute sulfuric acid solution that can be recycled.

[0040] 2. The processing operation is relatively simple and the processing cost is low. The dilute sulfuric acid solution after processing can also bring certain economic benefits when used for other purposes. Detailed Implementation

[0041] Example 1:

[0042] The data in the examples are taken from the production example of the company where the researchers of this application work on the treatment of waste sulfuric acid liquid generated in the large-scale production of 2-adamantanone. The sulfuric acid content of the waste sulfuric acid liquid to be treated is about 35% to 37%. The appearance is grayish-black slurry due to the presence of a lot of suspended polymeric colloids, and it emits a distinct foul odor.

[0043] The processing steps are as follows:

[0044] 1. Preparation of a special adsorbent-coagulant paste:

[0045] The bentonite material used is inorganic mineral bentonite powder, and the organic solvent is petroleum ether (distillation range of 60℃~90℃ or 90℃~120℃) or n-hexane. The dilute sulfuric acid solution is directly recycled dilute sulfuric acid solution with a content of about 60% that has been previously treated.

[0046] The materials are metered and fed according to the ratio of bentonite: organic solvent: dilute sulfuric acid solution = 2:1.5:15 (mass ratio).

[0047] First, add the organic solvent to the glass-lined reactor and start stirring. Then, add the bentonite in batches, stirring for 5-10 minutes, and then stop stirring. Let it stand for 1-2 hours to allow the bentonite and organic solvent to swell and coat each other.

[0048] Add dilute sulfuric acid solution to the reactor, stir the agitator a few times until the expanded bentonite material floats to the surface, then start the agitator and stir for about 0.5 hours to obtain a thin paste-like slurry.

[0049] The operation process usually does not require manual temperature control, allowing the material to be naturally maintained within the range of 20℃ to 40℃.

[0050] Prepare a large quantity of paste using the method described above and store it in the reactor without discharging it for production use (stir for a few minutes before use).

[0051] 2. Treatment of waste sulfuric acid solution

[0052] (1) Add approximately 1000 kg of the waste sulfuric acid solution to the glass-lined reactor, start stirring (stirring speed 120 rpm) and heat to 40℃~50℃ and maintain the temperature. Add approximately 47 kg of the previously prepared paste to the reactor, continue stirring for about 30 minutes, take a sample of the purified acid solution from the material to confirm that the polymeric colloids have been completely coagulated and removed, stop stirring, discharge the material in the reactor into the coagulation tank, and let it stand naturally for 6~8 hours.

[0053] (2) After thoroughly removing the sludge from the surface of the material in the coagulation tank using a tool (and dispose of it separately), pump the acid solution into a glass-lined reactor, stir and heat it to a range of 50℃~60℃ and maintain it, add about 3Kg of activated carbon powder, continue stirring for about 1 hour, then cool it to a range of 20℃~30℃ and stop stirring. Discharge the material in the reactor and filter out the activated carbon solid sludge through a filter screen.

[0054] (3) Pump the filtered acid solution into a glass-lined evaporation and concentration kettle, start stirring and start the vacuum equipment to create negative pressure in the kettle, heat and evaporate, concentrate until the sulfuric acid solution concentration reaches 61% to 62% (at this time the water evaporation rate is very slow), restore the normal pressure in the kettle, and cool down to 40℃ to 50℃.

[0055] (4) Maintain the temperature of the material inside the reactor within the range of 40℃~50℃. Add hydrogen peroxide dropwise to the acid solution in the reactor from the high-level tank in batches. After each batch is added, take a sample to test the residual sulfur dioxide content. When the total amount of hydrogen peroxide added reaches 8.3Kg, and the residual sulfur dioxide content is found to be below 0.2%, stop adding hydrogen peroxide. Cool the sulfuric acid solution in the reactor to 30℃~35℃, transfer it to an intermediate storage tank, and store it in drums.

[0056] Approximately 593 kg of a light yellow, pure sulfuric acid solution was collected, with a sulfuric acid content of 60.7%.

[0057] Example 2:

[0058] The sulfuric acid content of the waste sulfuric acid solution to be treated here is about 35.7%. Due to the presence of a large amount of suspended polymeric colloids, it appears as a grayish-black slurry and emits a distinct foul odor.

[0059] The processing steps are as follows:

[0060] 1. Preparation of a special adsorbent-coagulant paste:

[0061] The bentonite material used is inorganic mineral bentonite powder, the organic solvent is petroleum ether (distillation range of 60℃~90℃), and the dilute sulfuric acid solution is directly the previously treated recycled dilute sulfuric acid solution with a content of 59.4%.

[0062] The materials are metered and fed according to the ratio of bentonite: organic solvent: dilute sulfuric acid solution = 2:1.5:15 (mass ratio).

[0063] At room temperature, first add the organic solvent to the glass-lined reactor and start stirring. Then, add bentonite in batches, stirring for 10 minutes, and then stop stirring. Let it stand for 1.5 hours to allow the bentonite and organic solvent to swell and coat each other.

[0064] Add dilute sulfuric acid solution to the reactor, stir the agitator a few times until the expanded bentonite material floats to the surface, then start the agitator and stir for about 0.5 hours to obtain a thin paste-like slurry.

[0065] Prepare a large quantity of paste using the method described above and store it in the reactor without discharging it for production use (stir for a few minutes before use).

[0066] 2. Treatment of waste sulfuric acid solution

[0067] (1) Add approximately 1000 kg of the waste sulfuric acid solution to the glass-lined reactor, start stirring (stirring speed 120 rpm), and heat to 45℃±1℃ and maintain the temperature. Add the previously prepared paste to the reactor in batches, stirring for 5 minutes after each addition and taking a sample for testing. After adding a total of 52 kg, take a sample of the clean acid solution from the material for testing to confirm that the polymeric colloids have been completely coagulated and removed. Continue stirring for about 30 minutes, then stop stirring and discharge the material from the reactor into a coagulation tank. Allow it to stand naturally for 7-8 hours under cooling conditions.

[0068] (2) After thoroughly removing the sludge from the surface of the material in the coagulation tank using a tool (and dispose of it separately), pump the remaining dilute sulfuric acid solution into a glass-lined reactor, stir and heat it to a range of 55℃±1℃, add about 3 kg of activated carbon powder, continue stirring for about 1 hour, then cool it to a range of 30℃±2℃ and stop stirring. Discharge the material from the reactor and filter out the activated carbon solid sludge through a filter screen.

[0069] (3) Pump the filtered acid solution into the glass-lined evaporation and concentration kettle, start the stirring and start the vacuum equipment to create negative pressure in the kettle, heat and evaporate, concentrate until the sulfuric acid solution concentration reaches 61% to 62% (at this time the water evaporation rate is very slow), restore the normal pressure in the kettle, and cool down to 45℃±1℃.

[0070] (4) Maintain the temperature of the material inside the reactor within the range of 45℃±1℃. Add hydrogen peroxide dropwise to the acid solution in the reactor from the high-level tank in batches. After each batch is added, take a sample to test the residual sulfur dioxide content. When the total amount of hydrogen peroxide added reaches 7.1 kg, and the residual sulfur dioxide content is found to be below 0.2%, stop adding hydrogen peroxide. Cool the sulfuric acid solution in the reactor to 30℃~35℃ and transfer it to an intermediate storage tank for later drum storage.

[0071] Approximately 587 kg of a light yellow, pure dilute sulfuric acid solution was collected, with a sulfuric acid content of 60.2%.

[0072] Example 3:

[0073] The sulfuric acid content of the waste sulfuric acid solution to be treated here was approximately 36.3%. Due to the presence of a large amount of suspended polymeric colloids, it appeared as a grayish-black slurry and emitted a distinct foul odor.

[0074] The processing steps are as follows:

[0075] 1. Preparation of a special adsorbent-coagulant paste:

[0076] The bentonite material used is inorganic mineral bentonite powder, the organic solvent is n-hexane (industrial grade), and the dilute sulfuric acid solution is directly recycled dilute sulfuric acid solution with a content of 60.4% that has been previously treated.

[0077] The materials are metered and fed according to the ratio of bentonite: organic solvent: dilute sulfuric acid solution = 2:1.5:15 (mass ratio).

[0078] The preparation method is the same as in Example 2.

[0079] 2. Treatment of waste sulfuric acid solution

[0080] The procedure for treating waste sulfuric acid is the same as in Example 2, wherein...

[0081] In operation step (1), add about 1000 kg of waste sulfuric acid solution to be treated and 45 kg of the previously prepared paste.

[0082] In step (2), add about 3 kg of activated carbon powder.

[0083] In operation step (4), add 6.4 kg of hydrogen peroxide.

[0084] After processing, approximately 591 kg of pure, light yellow dilute sulfuric acid solution was measured and collected, with a sulfuric acid content of 60.7%.

Claims

1. A method for treating and recovering waste sulfuric acid liquid from the production of 2-adamantanone, characterized in that, include: (1) Preparation of special adsorbent-coagulant paste: First, mix and soak the bentonite with an organic solvent. After it swells, vigorously mix it with dilute sulfuric acid solution to form a paste. (2) Add the paste prepared in step (1) above to the waste sulfuric acid solution to be treated, stir vigorously at 40℃~50℃ to mix and disperse it fully, then let it stand and let it cool down to room temperature naturally until the solid material in the waste sulfuric acid solution floats to the surface and agglomerates into coarse particles; (3) Separate and remove the coarse solid particles from the surface of the material, and then use activated carbon powder to adsorb and remove the fine aggregated particles remaining in the dilute sulfuric acid solution at 50℃~60℃; (4) The dilute sulfuric acid solution after filtering out the activated carbon solid material is evaporated under reduced pressure and concentrated until the sulfuric acid content reaches 60%. Then hydrogen peroxide is added to the dilute sulfuric acid solution and reacted at 40℃~50℃ to oxidize and remove the residual sulfur dioxide, so as to obtain a relatively pure dilute sulfuric acid solution. (1) The bentonite used is inorganic mineral bentonite; the organic solvent used is petroleum ether with a boiling range of 60℃~120℃, solvent oil with a boiling range of 60℃~120℃, n-hexane, n-heptane or n-octane; the concentration of the dilute sulfuric acid solution used is 55%~65%; In (1), the mass ratio of bentonite: organic solvent: dilute sulfuric acid is 2:(1~2):15, and the operating temperature is room temperature.

2. The method for treating and recovering waste sulfuric acid liquid from 2-adamantanone production according to claim 1, characterized in that, (2) The mass ratio of waste sulfuric acid liquid to paste is 100:2 to 8. The specific amount of paste added depends on the content of suspended polymers in the waste sulfuric acid liquid, and should be based on the ability to fully adsorb and aggregate the suspended polymers in the waste sulfuric acid liquid.

3. The method for treating and recovering waste sulfuric acid liquid from 2-adamantanone production according to claim 1, characterized in that, (3) In this case, the ratio of waste sulfuric acid solution to activated carbon powder is 100:0.2 to 0.5 by mass.

4. The method for treating and recovering waste sulfuric acid liquid from 2-adamantanone production according to claim 1, characterized in that, (4) The amount of hydrogen peroxide added is based on the complete oxidation of residual sulfur dioxide.