457 results about "Nitration" patented technology

The invention belongs to the technical field of sewage treatment, and particularly relates to an anaerobic ammonia oxidation-photoelectric denitrification deep nitrogen removal method. The method comprises the following steps: firstly, adopting a double-chamber reactor; introducing part of sewage into the cathode chamber, carrying out Anammox reaction under a dark state condition to remove ammonia nitrogen and part of nitrite nitrogen, and synchronously generating nitrate nitrogen; turning on a light source to irradiate the anode chamber, exciting photo-induced electrons by a photosensitizer, transmitting the photo-induced electrons to the cathode chamber through an external circuit, and driving the sulfur autotrophic denitrification sludge to reduce residual nitrite nitrogen and nitrate nitrogen generated by Anammox; the total nitrogen removal rate is close to 100%. According to the invention, photo-induced electrons are used as the only denitrification electron donor, so that the addition of a carbon source / sulfide is thoroughly avoided, and the risk of secondary pollution is eliminated. The method is suitable for green low-carbon deep treatment of sludge digestion liquid and pharmaceutical wastewater high-ammonia-nitrogen low-carbon-nitrogen-ratio sewage.

The invention relates to a particulate composition comprising, or substantially consisting of, urea, an inhibitor, preferably a urease inhibitor and / or a nitrification inhibitor, and an additive, wherein the additive comprises components (i), (ii), and optionally (iii): (i) one or more polyhydric alcohols; preferably one or more carbohydrates, preferably selected from monosaccharides, disaccharides, and oligosaccharides; (ii) a first polymer, preferably an amine-containing polymer; more preferably a polyvinylamine or a polyalkyleneimine; and (ii) optionally, a second polymer, preferably a polar polymer; more preferably a water-soluble polar polymer. The invention further relates to a process for producing the particulate composition, an additive for a particulate composition, and the use of the particulate composition as a fertilizer.

The invention belongs to the field of microorganisms, and particularly relates to a high-efficiency denitrification heterotrophic nitrification-aerobic denitrification klebsiella and a culture method and application thereof.A biological material of the high-efficiency denitrification heterotrophic nitrification-aerobic denitrification klebsiella is named as Klebsiella oxytoca CT4 and is preserved in Guangdong Microbial Culture Collection Center (GDMCC) on July 21, 2025, the preservation number of the Klebsiella oxytoca CT4 is CGMCC NO.9687, and the preservation number of the Klebsiella oxytoca CT4 is CGMCC NO.987. The preservation address is Institute of Microbiology, Guangdong Academy of Sciences, on the fifth floor of building 59, No. 100 courtyard, Xianlie Middle Road, Guangzhou, Guangdong Province; the preservation number of the strain is GDMCCNO: 66723; according to the strain, the ammonia nitrogen removal rate can reach 98.7% through nitrification-denitrification, the nitrite accumulation amount in the whole process is lower than 0.5 mg / L, and accumulation of toxic intermediate products is avoided. The strain has wide environmental adaptability, can keep efficient denitrification activity under the conditions that the pH is 5.0-10.0 and the C / N ratio is 5-30, can tolerate fluctuation of wastewater quality, does not need to repeatedly adjust the pH value when being used for treating aquaculture wastewater with a high C / N ratio (greater than 20), and can still stabilize the total nitrogen removal rate to be 80% or above, so that the addition cost in a conventional process is remarkably reduced.

The invention belongs to the technical field of energetic plasticizer preparation, and particularly discloses a method for preparing N-butyl nitroxyethyl nitramine through ionic liquid nitration. The method comprises the following steps: mixing an ionic liquid nitrating agent with butyl ethanolamine to obtain a mixed solution; and mixing the mixed solution with a catalyst and acetic anhydride, reacting, and carrying out post-treatment to obtain the N-butyl nitroxyethyl nitramine. According to the method, the ionic liquid with stable properties is adopted as the nitrating agent, the reaction is mild when the ionic liquid is mixed with the butylethanolamine, violent heat release caused when fuming nitric acid is in contact with the butylethanolamine is effectively avoided, and the ionic liquid precursor can be recycled through simple extraction after the reaction.

The pure membrane MBBR sewage treatment system comprises an anoxic denitrification zone, an anaerobic ammonia oxidation zone, an aerobic oxidation zone, a high-density sedimentation zone, an MBBR biological filtration zone, a backwashing water tank and an equipment room, the anoxic denitrification region is used for carrying out amination reaction, organic matter hydrolysis reaction and denitrification reaction on the sewage and nitrate and nitrite in the anoxic denitrification region; the anaerobic ammonia oxidation zone is used for reacting the sewage with nitrite to generate nitrogen; the aerobic oxidation zone is used for promoting microorganisms to degrade organic matters in sewage and convert ammonia nitrogen; the high-density settling zone is used for separating muddy water in sewage; the MBBR biological filtration area is used for filtering suspended matters in the sewage; the backwashing water tank is used for providing backwashing make-up water for the MBBR biological filtration area; and the equipment room is used for placing disinfection equipment, a fan and a power distribution control system.

The invention discloses a method for realizing deep autotrophic nitrogen removal of sludge digestion liquid based on alternate intermittent aeration of a double-membrane aeration bio-membrane reactor (MABR). The process device comprises a sludge digestion liquid raw water tank, a single-stage double-MABR reactor, two MABR devices and a water outlet tank. According to the method, sludge digestion liquid enters the single-stage double-MABR reactor, the two MABR devices are alternately and intermittently aerated, the state of one aeration and one aeration stopping is always kept, and ammonia nitrogen in raw water is converted into nitrite through ammonia oxidizing bacteria enriched on the inner side of an MABR membrane. And simultaneously supplying to anaerobic ammonium oxidation bacteria enriched on the outer sides of the two MABR membranes through matrix diffusion for denitrification and generation of nitrate. Denitrifying bacteria enriched on the outer side of the MABR membrane utilize raw water organic matters to drive short-cut denitrification to synchronously supply nitrite to anaerobic ammonium oxidation bacteria so as to realize deep autotrophic nitrogen removal. According to the invention, a double-anaerobic ammonia oxidation reaction hot area is constructed through alternate intermittent aeration of double MABRs, and efficient deep autotrophic nitrogen removal of the sludge digestion liquid can be stably realized.

The application provides a method for continuously preparing nitrobenzene by using benzene and NO2 as raw materials. The method is characterized in that: a solid catalyst capable of catalyzing the nitration of benzene by NO2 is filled in a pipe reactor, benzene, NO2 and O2 are continuously fed into the pipe reactor at a certain flow rate, and the reaction is carried out at a certain temperature to obtain nitrobenzene. This route is safe, green, economical and efficient, and is a safe, green, economical and efficient nitrobenzene synthesis route.

The invention discloses an asphalt-based double-salt template porous carbon electrode material as well as a preparation method and application thereof, and relates to the technical field of porous carbon electrode materials. The preparation method sequentially comprises the following steps: adding asphalt into concentrated nitric acid, stirring for reaction, and washing to obtain a nitration product; and uniformly mixing the nitration product, active organic potassium salt and inert inorganic carbonate, performing ball milling, then performing pre-oxidation and carbonization treatment, and washing to be neutral to obtain the asphalt-based double-salt template porous carbon electrode material. The invention also discloses the asphalt-based double-salt template porous carbon electrode material and application of the asphalt-based double-salt template porous carbon electrode material in removal of nitrate radicals and ammonia nitrogen in a water body through a capacitive deionization technology. According to the invention, a macropore-mesopore-micropore synergistic hierarchical pore structure is constructed in an asphalt carbon skeleton through a double-salt template, efficient adsorption of two nitrogen pollutants of nitrate and ammonia nitrogen is realized, and the method has important practical application value.

The invention relates to the technical field of environmental microbial resource development and sewage denitrification. The invention discloses an efficient denitrification strain Paracoccus sp.N21 with a flocculation characteristic, which is preserved in the China General Microbiological Culture Collection Center (CGMCC), and the preservation number is CGMCC No.34710. The invention further discloses a preparation method of the efficient denitrification strain Paracoccus sp.N21. The strain obtained by the invention can completely remove ammonia nitrogen within 12 hours and thoroughly remove nitrate nitrogen within 48 hours, the removal rate reaches 100%, and ammonia nitrogen is preferentially degraded in a mixed nitrogen source. The method has the unique advantages that the flocculation rate in the nitrification process and the flocculation rate in the denitrification process exceed 93.9%, and the usage amount of a flocculating agent can be greatly reduced. When actual kitchen wastewater is treated, the ammonia nitrogen removal rate reaches 100%, and the removal rate reaches up to 7.51 mg / (L.h). The application of the strain can effectively reduce the volume of a reactor, reduce energy consumption and operation cost, provides a new solution for simplifying a biological denitrification process, is particularly suitable for treating high-ammonia-nitrogen kitchen wastewater, and has remarkable environmental and economic benefits.

The application provides a synthesis method of p-benzoquinone dioxime. The synthesis method comprises the following steps: (1) adding solid acid into an ethanol solution of phenol to obtain a mixed solution A, then vacuumizing and filling with inert gas; dissolving nitrite into ethanol, uniformly mixing to obtain an ethanol solution of nitrite, then vacuumizing and filling with inert gas; in an inert gas atmosphere, adding the ethanol solution of nitrite into the mixed solution A dropwise to perform nitrosation reaction, to obtain a reaction liquid B; in the inert gas atmosphere, adding an ethanol solution of hydroxylamine into the obtained reaction liquid B to perform oximation reaction; after the reaction is completed, filtering the obtained reaction liquid C, performing reduced pressure distillation on the obtained filtrate, and performing washing, filtering and drying on the obtained residual liquid of the reduced pressure distillation, to obtain p-benzoquinone dioxime. The method provided by the application reduces the occurrence of side reactions, improves the conversion rate of the reaction, and improves the yield and purity of p-benzoquinone dioxime.

The invention discloses a preparation method of 6-nitro-m-cresol, and belongs to the technical field of organic synthesis.The method comprises the steps that raw materials are subjected to esterification, water washing, sulfonation, nitration, desulfonation and refining in sequence, and the 6-nitro-m-cresol is obtained. According to the method, it can be guaranteed that the intermediate product is the 6-nitro derivative, generation of isomer impurities such as 2-site and 4-site is greatly reduced from the source, the reaction path is clear, and atom economy is good. The method does not need to depend on complicated means such as time-consuming column chromatography or precise fractionation, the requirement for high purity can be met only through conventional extraction and crystallization operation, the technological process is simple, the method is very suitable for large-scale production, and the product purity (measured through HPLC (High Performance Liquid Chromatography)) can stably reach 98% or above.

The invention relates to the field of chemical equipment, in particular to a 1-nitroanthraquinone continuous production process based on a dynamic liquid membrane continuous flow reactor, which comprises a solid feeding device, a homogeneous emulsifier, a quenching kettle, a solid-liquid separator, a centrifugal separator and a dynamic liquid membrane reactor, a sulfuric acid storage tank is divided into two branches through a sulfuric acid feeding pump, one branch is connected to the dynamic liquid membrane reactor, the other branch is connected to the dynamic liquid membrane reactor through a flow self-control valve, the quenching kettle is connected to a solid-liquid separator, the solid-liquid separator is divided into two branches, one branch is connected to an anthraquinone crude product storage tank, the other branch is connected to a centrifugal separator, and the other branch is connected to a gas-liquid separator. The centrifugal separator is divided into two branches, one branch is connected to the acid water storage tank, and the other branch is connected to the dichloroethane storage tank, so that the reaction selectivity of the anthraquinone nitration reaction can be effectively improved, high-viscosity solids are prevented from being blocked, and the conversion rate of raw materials in the continuous reaction of the anthraquinone nitration reaction is improved.

The present application relates to the technical field of microorganism, and provide a kind of low temperature resistant nitrosomonas and its application.The nitrosomonas is nitrosomonas (Nitrosomonas europaea.) H1, and the preservation number is CCTCC NO:M 2024693.The nitrosomonas H1 of the present application has the characteristics of low temperature resistance, grows well at 10 DEG C, and has good ammonia oxidation capacity, is suitable for the treatment of northern winter low temperature wastewater, and does not need to be heated or take other measures to maintain the stability of biochemical system.

Fertilizers with urease inhibitors and / or nitrification inhibitors are described. The fertilizer can include an extruded granule containing urea, a polymeric binder, and a nitrification inhibitor and / or an urease inhibitor.

The invention discloses a synthesis method of 5-(1H-pyrrole-1-yl)-2-mercaptobenzimidazole, which comprises the following steps: carrying out cyclization condensation reaction on o-phenylenediamine and thiourea in an acidic environment provided by hydrochloric acid to obtain 2-mercaptobenzimidazole; the preparation method comprises the following steps: carrying out nitration reaction on 2-mercaptobenzimidazole, sulfuric acid and nitric acid to obtain 2-mercapto-5-nitrobenzimidazole; the preparation method comprises the following steps: carrying out nitro reduction reaction on 2-sulfydryl-5-nitrobenzimidazole and hydrogen under the catalysis of nickel to obtain 5-amino-2-sulfydryl benzimidazole; the preparation method comprises the following steps: carrying out an N-alkylation reaction on 5-amino-2-mercapto benzimidazole and tetrahydro-2, 5-dimethoxyfuran under the catalysis of copper chloride to generate 5-(1H-pyrrole-1-yl)-2-mercapto benzimidazole, and carrying out a reaction on the 5-amino-2-mercapto benzimidazole and tetrahydro-2, 5-dimethoxyfuran to generate the 5-(1H-pyrrole-1-yl)-2-mercapto benzimidazole. The method disclosed by the invention has the outstanding advantages of mild and easily-controlled conditions, simple and convenient post-treatment, high yield, economy, environmental protection, suitability for large-scale production and the like, conforms to the green chemical development concept, and has important application value.

The invention discloses a method for preparing nitro-mesitylene through a micro-channel nitration reaction. The method comprises the following steps: respectively conveying mesitylene, fuming nitric acid and sulfuric acid to a micro-channel reaction module through a metering pump, and completing nitration reaction within a retention time of tens of seconds to several minutes. The introduction sequence of nitration reaction materials, the reaction retention time and the reaction temperature are cooperatively controlled, the nitration reaction is completed in the microchannel reactor in a continuous flow mode, operation is easy and convenient, safety is high, efficient continuous production can be achieved, meanwhile, emission of three wastes is reduced, and the industrial application advantages of being environmentally friendly and economical are achieved.

The invention discloses tetraacetyl dicyclopropyl hexaazaisowurtzitane, a preparation method thereof and a synthesis method of HNIW, and belongs to the technical field of chemical synthesis. The tetraacetyl dicyclopropyl hexaazaisowurtzitane disclosed by the invention is a novel hexaazaisowurtzitane derivative, and the preparation method of the tetraacetyl dicyclopropyl hexaazaisowurtzitane has the advantages of short reaction steps, simplicity in operation, easily available raw materials and industrial application potential. The tetraacetyl dicyclopropyl hexaazaisowurtzitane disclosed by the invention can be used for synthesizing hexanitrohexaazaisowurtzitane (HNIW) in one step through nitration, so that the synthesis process is simplified, and the production cost is reduced; the specific gravity of the leaving group cyclopropyl in the cyclopropylamine raw material is small, the atom economy is good, the utilization rate of the raw material is high, waste discharge is reduced, and the method conforms to the environmental protection concept of green economy.

The invention relates to a process for producing nitrobenzene by an adiabatic nitration of benzene (2) and nitric acid (1) in the presence of sulfuric acid (7), the process comprising: (a) feeding benzene (2), nitric acid (1) and sulfuric acid (7) into a reaction zone (R); (b) producing a reaction mixture (4) comprising water, nitrobenzene and sulfuric acid by reaction of the benzene and the nitric acid in the presence of the sulfuric acid in the reaction zone (R); and (c) separating the reaction mixture into an aqueous phase (6) comprising water and sulfuric acid and an organic phase (5) comprising crude nitrobenzene by phase separation; wherein the concentration of titanium in the reaction mixture (4) is kept below 170 mg / kg.

The present invention relates generally to nitrification inhibitors and their use to prevent nitrate leaching or nitrous oxide emissions and to increase forage or crop yield. The present invention also relates to nitrification inhibitors and formulations comprising the same for direct or indirect application to soil or pasture.

This invention discloses a continuous synthesis apparatus and process for nitrobenzene. The synthesis apparatus includes a mixed acid preparation system, a continuous benzene nitration system, an organic phase continuous stratification system, and a continuous water washing-alkali washing-water washing system. The process includes: concentrated sulfuric acid and concentrated nitric acid are pumped into the mixing module of the mixed acid preparation system to obtain a mixed acid solution; benzene and the mixed acid solution are pumped into the microchannel reactor of the continuous benzene nitration system; the nitrated material is cooled and then pumped into the continuous organic phase stratification system; the resulting intermediate organic phase nitrate enters the next processing unit; the organic phase nitrate and water enter the continuous water washing-alkali washing-water washing system for washing to obtain the final product, nitrobenzene. The synthesis apparatus and process of this invention achieve continuous production of nitrobenzene throughout the entire process, realizing continuous and automated operation from raw material benzene to the final product, nitrobenzene.

The invention belongs to the field of intelligent control of sewage treatment, and particularly provides an anoxic tank nitrate optimization control method and system based on dynamic grading of total nitrogen in inlet water, a storage medium and equipment. Calculating a control value of nitrate nitrogen at the tail end of the anoxic tank; calculating the total amount of nitration nitrogen removed by the inlet water carbon source, calculating the total amount of nitration nitrogen needing to be removed by adding the carbon source according to the anaerobic tank-anoxic tank nitration nitrogen load, the total amount of nitration nitrogen removed by the inlet water carbon source and the anoxic tank nitrate nitrogen control value, and calculating the adding amount of the carbon source needing to be added according to the total amount of nitration nitrogen needing to be removed by adding the carbon source; and monitoring the actual nitrate nitrogen concentration at the tail end of the anoxic tank, comparing the actual nitrate nitrogen concentration with the nitrate nitrogen control value at the tail end of the anoxic tank, and adjusting the adding amount of the carbon source. By monitoring inlet water and process parameters in real time, integrating microbial assimilation, dynamically calculating the control threshold value of nitrate in the anoxic tank and then calculating the basic adding amount of the carbon source, it is guaranteed that the total nitrogen in total outlet water stably reaches the standard, and the consumption of the carbon source is reduced.

The invention discloses a sulfur autotrophic denitrification system monitoring and control method and system based on machine learning, and the method comprises the steps: collecting system operation parameter data in real time, inputting the system operation parameter data into a first machine learning model, and predicting the effluent nitrate nitrogen concentration of the system by the model; when the predicted concentration value is higher than a preset emission standard threshold value, an early warning signal is triggered; identifying key influence factors with high effluent nitrate nitrogen concentration value by adopting an SHAP interpretability analysis method, and carrying out quantitative sequencing on influence degrees of the factors; based on the obtained key influence factors and related data, a bimodal load management strategy or a precise chemical dosing strategy is selected and executed, and the effluent nitrate nitrogen concentration of the system is controlled within the emission standard threshold value range. The sulfur autotrophic denitrification system is subjected to monitoring-diagnosis-control closed-loop intelligent management, so that refined and active regulation and control of the sulfur autotrophic denitrification process are realized, and the operation stability, the treatment efficiency and the economical efficiency of the system are improved.

This invention discloses a denitrification biological carrier, its preparation method, and its application. The raw materials for preparing the denitrification biological carrier include an iron agent, modified activated carbon, polycaprolactone, sodium dodecyl sulfate, and a hydrogel binder. The modified activated carbon is 3-chloro-2-hydroxypropyltrimethylammonium chloride-modified activated carbon. The iron agent not only removes dissolved oxygen from water but also reduces total nitrogen in wastewater. The modified activated carbon improves its adsorption affinity for nitrogen-containing compounds. Polycaprolactone serves as a slow-release carbon source for denitrification, exhibiting high carbon source utilization. Sodium dodecyl sulfate, through its foaming properties, together with the modified activated carbon, iron agent, and polycaprolactone, forms a high-mechanical-strength, rough, and porous biological carrier structure, providing excellent attachment conditions for heterotrophic denitrifying bacteria. Therefore, applying the denitrification biological carrier of this invention to wastewater treatment systems can achieve good nitrogen removal efficiency and economic benefits.

The application relates to a method and device for degrading ethion and recycling heavy metals simultaneously based on an endogenous sulfur cycle, and belongs to the technical field of dressing wastewater treatment. The device is mainly composed of sequentially connected MABR and H2-MBfR. In the method, ethion is oxidized and degraded to produce CS2 and ammonia nitrogen under aerobic conditions in the MABR, and the CS2 is further converted into sulfate; the ammonia nitrogen is nitrified into nitrate nitrogen and nitrite nitrogen. Subsequently, the effluent enters the H2-MBfR, and under anaerobic conditions, the nitrate nitrogen and the nitrite nitrogen are reduced into nitrogen gas by taking hydrogen as an electron donor, and the endogenous sulfate is reduced into sulfur ions; the sulfur ions react with heavy metal ions in situ to generate metal sulfide precipitates. Finally, the precipitates are recovered through solid-liquid separation and are reused for metal flotation. The application realizes directional conversion and collaborative removal of pollutants, does not produce secondary pollution, and realizes recycling of heavy metal resources by using the sulfur element of the pollutants.

The invention provides a method for preparing 2, 6-diamino-3, 5-dinitropyridine, which comprises the following steps: (1) reacting 2, 6-diaminopyridine with an amino protection reagent to obtain an intermediate A; (2) in the presence of a dehydrating agent, carrying out double nitration reaction on the intermediate A and a nitration reagent to generate an intermediate B; (3) 2, 6-diamino-3, 5-dinitropyridine is obtained after the intermediate B is subjected to deprotection, and an amino protection reagent is selected from one or more of acetic anhydride, trifluoroacetic anhydride, di-tert-butyl dicarbonate, benzyl chloroformate and concentrated sulfuric acid; wherein the molar ratio of the amino protection reagent to the 2, 6-diaminopyridine is (2: 1)-(30: 1) by mole; and preferably, the ratio is 2: 1-12: 1.

This invention discloses a complete process for preparing nitrobenzene using a microchannel reactor, belonging to the field of nitrobenzene synthesis. The complete process includes mixed acid, microchannel nitration reaction, intermediate product cooling and stratification followed by water and alkali washing, crude product distillation, waste acid recovery, and wastewater treatment. Compared with existing nitrobenzene synthesis technologies, this invention has high mass transfer efficiency, significantly shortens the nitration reaction time, greatly improves production efficiency, enhances reaction safety, and simultaneously achieves waste acid recovery and wastewater treatment, ensuring safe, environmentally friendly, and stable production.

This utility model discloses an aerobic mixed liquor nitrification and deoxygenation treatment device, including a first nitrification tank. A nitrite-containing bacteria storage tank is located at the top of the first nitrification tank. An inlet pipe is located at the top of one side of the first nitrification tank, and one side of the inlet pipe extends into the interior of the first nitrification tank and is equipped with a sludge-water separation chamber. Through the cooperation of the inlet pipe, sludge discharge pipe, screen, and sludge-water separation chamber, this utility model can separate the sludge mixed in with the mixed liquor during its inflow, while also facilitating the return of the sludge to the treatment tank. Then, through the cooperation of a second discharge pipe, a third pump, a pump installation chamber, a distribution plate, a distribution pipe, a heat dissipation chamber, and a fan, the mixed liquor can be continuously circulated and cooled during the nitrification reaction, thereby maintaining the mixed liquor at 20-30°C to preserve the activity of nitrite-containing bacteria and nitrifying bacteria in the mixed liquor and ensure reaction efficiency.

The invention relates to the technical field of drug detection and analysis, in particular to a diiodide detection method, dichloromethane-acetone-methanol-ammonia water (7: 1: 1: 1) is used as a developing solvent, the concentration of diiodide in reaction liquid during nitration reaction of diiodide in the lobaplatin production process is detected, the method can accurately judge whether nitration reaction is complete or not, and the detection result is accurate. And the diiodide is ensured to be completely reacted in the nitration reaction process. The obtained method is suitable for detecting and judging the lobaplatin nitration reaction endpoint, the result is accurate and reliable, good specificity, durability and solution stability are achieved, and the detection time is short.

The invention relates to the technical field of Stefan acid purification, in particular to a method for purifying Stefan acid from a dinitrobenzene nitration byproduct mixture, which comprises the following steps: S1, dissolving the dinitrobenzene nitration byproduct mixture in water, adjusting the pH value to be alkaline, and filtering to obtain filtrate and filter residue dinitrobenzene solid; s2, adding the filtrate into an organic solvent, extracting, separating liquid, and retaining a water phase; and S3, adjusting the pH value of the water phase to be acidic, heating for acid precipitation, and then cooling for crystallization to obtain a mixed crystal of Stefan acid and picric acid. And S4, heating and mixing the mixed crystal and toluene, and filtering to obtain the high-purity Stefan acid. According to the method, efficient separation is realized through a two-step core process of'alkali dissolution-acidification 'and'selective dissolution'. In the final product, the content of dinitrobenzene can be reduced to 0%, the content of picric acid can be reduced to 1% or below, and the purity of Stefan acid can reach 99% or above.