187 results about "Dinitrobenzene" patented technology

The invention relates to the technical field of chemical synthesis, in particular to a preparation method of 3, 4 '-diaminodiphenyl ether.The preparation method comprises the steps that m-dinitrobenzene is dissolved with alcohol, and selective hydrogenation is conducted in a high-temperature and high-pressure reaction kettle with a palladium catalyst; and co-heating and refluxing the product after selective hydrogenation, a strong alkali aqueous solution, a first solvent and a phase transfer catalyst to obtain the m-aminophenol salt. M-aminophenol salt, p-nitroiodobenzene, alkali and a second solvent are subjected to a co-heating reaction, and then 3-amino-4 '-nitrodiphenyl ether is obtained through post-treatment; the method comprises the following steps: dissolving 3-amino-4 '-nitrodiphenyl ether with alcohol, carrying out hydrogenation reduction with a palladium catalyst, and carrying out post-treatment purification to obtain 3, 4'-diaminodiphenyl ether. According to the method, common m-dinitrobenzene is used as a raw material, m-nitroaniline is obtained through selective hydrogenation, m-aminophenol salt is prepared through the m-nitroaniline, then etherification reaction is carried out, the reaction yield is higher, the purity is better, and side reactions are few.

The invention relates to the technical field of organic chemical synthesis, in particular to a preparation method of 3, 4 '-diaminodiphenyl ether.The preparation method comprises the steps that S1, under inert gas and in a first solvent, m-dinitrobenzene and p-acetamidophenol are subjected to a heating reaction under the condition of a weak base catalyst, and 3-nitro-4-acetamido diphenyl ether is prepared; s2, in a second solvent, the 3-nitro-4-acetamido diphenyl ether is subjected to a hydrogenation reduction reaction, and 3-amino-4-acetamido diphenyl ether is prepared; and S3, dissolving the 3-amino-4-acetaminodiphenyl ether in an alcohol solvent system, adding an aqueous solution of alkali, controlling the reaction temperature, carrying out a hydrolysis reaction, and after the reaction is finished, carrying out post-treatment to obtain the 3, 4 '-diaminodiphenyl ether. The preparation method provided by the invention has the advantages of easily available raw materials, low price, good selectivity and high product yield, and is more suitable for industrial production by comprehensively considering economical efficiency and safety.

The present invention discloses a nitration tail gas absorption treatment system applied to mixed dinitrobenzene production, and relates to the technical field of mixed dinitrobenzene production, the nitration tail gas absorption treatment system comprises an absorption tank, the top end and the bottom end of the absorption tank are respectively provided with a gas outlet and an absorption liquid discharge port, an absorption liquid adding opening and a waste gas introduction pipe are arranged at the positions, close to the top end and the bottom end, of one side of the absorption tank correspondingly, one end of the waste gas introduction pipe extends into the absorption tank and is connected with a gas distribution mechanism, and an absorption liquid lifting and spraying mechanism is arranged in the absorption tank; the absorption liquid lifting and spraying mechanism comprises a lifting pipe, and a plurality of absorption liquid sprayers are communicated with the position, close to the top end, of the periphery of the lifting pipe. According to the invention, the defects in the prior art are overcome, all the components cooperate closely, the absorption treatment efficiency of the nitration tail gas is improved, the stability and reliability are good, long-term stable operation can be realized, the manual intervention demand is reduced, and the operation cost is reduced.

The invention provides a high-temperature-resistant desulfurization catalyst and a preparation method thereof, and relates to the technical field of catalysis, and the high-temperature-resistant desulfurization catalyst comprises the following components in percentage by weight: 30-35% of cobalt phthalocyanine, 10-15% of Fe-PBTCA-EDTMP, 10-15% of manganese sulfate monohydrate, 10-15% of 2, 3, 4-trimethyl-1, 3-pentanediol monoisobutyrate, 10-15% of 2, 3, 4-trimethyl-1, 3 The cleaning agent is prepared from 5-10% of 1, 4-dinitrophenol, 15-20% of tannin extract, 8-10% of sodium metavanadate, 8-10% of ammonium phosphate and 4-8% of ammonia-ammonium chloride solution. The high-temperature-resistant desulfurization catalyst disclosed by the invention has the advantages of being small in dosage, small in waste liquid discharge, good in regeneration effect, low in corrosion rate, low in operation cost, not easy to block a tower, capable of overcoming hydrogen cyanide poisoning, high-temperature-resistant and not easy to inactivate. In a wet oxidation desulfurization system, the high-temperature-resistant desulfurization catalyst provided by the invention overcomes the defects that a PDS desulfurization catalyst, an MSQ desulfurization catalyst, a vanadium pentoxide + tannin extract catalyst and an ADA catalyst are easy to inactivate and secondary salts in a desulfurization solution are increased quickly when the desulfurization solution is at a high temperature of 70 DEG C. In addition, the high-temperature-resistant desulfurization catalyst overcomes the defects that a complex iron catalyst is high in corrosivity, large in usage amount, prone to tower blockage and the like.

The invention discloses a modified manganese dioxide positive electrode material and a preparation method and application thereof, and relates to the technical field of electrochemical energy storage, and the modified manganese dioxide positive electrode material comprises p-dinitrobenzene surface modified manganese dioxide. The modified manganese dioxide positive electrode material provided by the invention has multiple active sites, and can optimize the energy storage characteristic of the battery in the aqueous zinc ion battery, improve the specific capacity and rate capability of the battery and prolong the cycle life of the battery.

The invention belongs to the technical field of catalyst preparation, and provides an M2 diatomic site catalyst for a reaction for preparing phenylenediamine through dinitrobenzene hydrogenation and a preparation method and application thereof.The catalyst is formed by anchoring transition metal M diatomic sites to the surface of a diamond-graphene carrier and is prepared by taking nano-diamond powder as a raw material through a one-step reaction. Annealing treatment is carried out at the high temperature of 750-850 DEG C, a diamond-graphene carrier of an sp3 atsp2 core-shell structure is constructed, and the surface defect density of the diamond-graphene carrier is regulated and controlled in the process; and depositing metal species on the surface of the carrier through ALD double-step deposition to obtain the M2 diatomic site catalyst with high density and stable structure. The M2 diatomic site catalyst is applied to a reaction for preparing a corresponding phenylenediamine compound through hydrogenation of a dinitrobenzene compound, and high conversion rate and high selectivity can be achieved with low metal loading capacity under mild conditions. The method can be popularized to construction of diatomic catalysts of various transition metals, and has a wide application prospect.

A non-targeted mass spectrometry identification method for tobacco carbonyl components, comprising the following steps: (1) preparing a tobacco sample extract liquid; (2) performing derivatization by using 2,4-dinitrophenylhydrazine (DNPH) to obtain a first tobacco sample; (3) replacing DNPH with DNPH-d3 for derivatization to obtain a second tobacco sample; (4) preparing a mixed tobacco sample; (5) preparing a blank sample; (6) performing UPLC-Orbitrap-HRMS analysis respectively on the first tobacco sample, the second tobacco sample, the mixed tobacco sample, and the blank sample to obtain raw LC-MS data; (7) processing the raw LC-MS data to obtain raw mass spectrum characteristic data; (8) performing multiple filtering on the raw mass spectrum characteristic data; and (9) performing structural annotation or identification on the finally reserved chromatographic peak to obtain tobacco carbonyl components. By means of multiple filtering of mass spectrum characteristic data, chromatography-mass spectrum information of noise or interference components in a raw data set is quickly eliminated, and composition information of aldehyde and ketone chemical components in a cigarette is obtained.

The invention discloses a high-temperature-resistant nylon composite material and a production process thereof, and belongs to the technical field of nylon composite material preparation. The high-temperature-resistant nylon composite material is prepared from the following components in parts by weight: 35-48 parts of nylon resin, 7-12 parts of a heat-resistant agent, 3-8 parts of a modified anticorrosive agent, 1-3 parts of calcium stearate, 1-3 parts of a flame retardant and 2-10 parts of glass fibers, and the heat-resistant agent is prepared from 2, 4-dinitrophenol, hydrazine hydrate, p-nitrobenzoic acid, triethylamine, polyphosphoric acid and 2, 4-dinitrophenol. The nylon composite material is prepared from 2, 2 '-bis (3, 4-dicarboxylic acid) hexafluoropropane dianhydride, and the modified anticorrosive agent is prepared from fluororubber, benzyltriethylammonium chloride, lithium aluminum hydride and isophorone diisocyanate. The nylon composite material prepared by the method has excellent high temperature resistance and corrosion resistance.

The invention discloses a clean production process of a sulfur black dye, which comprises the following steps: S1, uniformly mixing dinitrochlorobenzene and a sodium hydroxide aqueous solution, and carrying out hydrolysis reaction to obtain a sodium dinitrophenolate solution; s2, uniformly mixing part of the sodium dinitrophenolate solution with a catalyst and a solvent, and carrying out hydrogenation reaction by using hydrogen to obtain a sodium diaminophenol solution; and S3, taking the sodium diaminophenol solution, the residual sodium dinitrophenol solution and the sodium polysulfide solution, and carrying out condensation reaction to obtain the sulfur black dye. According to the production process, hydrogenation reduction clean production is adopted, the generation amount of three wastes can be greatly reduced, especially the amount of salt-containing wastewater can be reduced by 20-90%, the content of pollutants in residual liquid is low, treatment is easy, environmental pollution is reduced, the production period is short, the efficiency is high, the product quality is stable, the process control is simple and convenient, and the color fastness of the obtained sulfur black dye is higher.

The invention belongs to the technical field of optical drive catalytic materials, and discloses a preparation method of a foamed ceramic-metal organic framework composite catalytic material and application of the foamed ceramic-metal organic framework composite catalytic material in photo-thermal catalytic elimination of nitro compounds. According to the invention, photo-thermal catalytic MOFs are loaded on foamed ceramic, and a floatable integrated photocatalytic material is formed through in-situ self-assembly and is used for solar-driven nitro-compound thermal elimination. MOFs have high specific surface area, high porosity, good light absorption and high photo-thermal conversion efficiency; the foamed ceramic has the characteristics of strong adsorbability, good heat conduction, light weight, adjustable size and the like. The combination of the two overcomes the problems of difficult recovery, more residues and low efficiency of the traditional powder catalyst and the high cost, high energy consumption, high-temperature danger and the like of the traditional photo-thermal catalysis, and shows huge application potential. The method can be used for treating organic wastewater containing toxic nitro compounds (such as trinitrotoluene, dinitrobenzene, nitrochlorobenzene and the like), and a new thought is provided for wastewater treatment in the fields of explosives, medicines, pesticides, dyes and the like.

The invention discloses a synthesis method of 2, 4, 5-trifluorophenylacetic acid, which comprises the following steps: by taking cheap and easily available o-chloronitrobenzene as a raw material, reacting with sodium nitrate in a sulfuric acid and trifluoroacetic acid system, separating generated 2, 4-dinitrochlorobenzene through melt crystallization, and continuing to synthesize 2, 4-dinitrochlorobenzene in methyl chloroacetate to obtain 2, 4, 5-trifluorophenylacetic acid. The method comprises the following steps: carrying out indirect aromatic nucleophilic substitution reaction on 2, 4-dinitrophenylacetic acid under the condition of sodium hydride to generate 5-chloro-2, 4-dinitrophenylacetic acid methyl ester, separating, carrying out fluorination reaction on the 5-chloro-2, 4-dinitrophenylacetic acid methyl ester and potassium fluoride under the action of a phase transfer catalyst, carrying out rectification separation to obtain 2, 4, 5-trifluorophenylacetic acid, and carrying out hydrolytic acidification on the 2, 4, 5-trifluorophenylacetic acid in a sodium hydroxide aqueous solution to obtain 2, 4, 5-trifluorophenylacetic acid. And the process route is safer, more environment-friendly, more efficient and lower in cost.

The present invention discloses a high-purity photochlorination synthesis method of p-fluorobenzoyl chloride, wherein an aromatic nitro compound or its salt is selected to form an inhibition system with triethanolamine, which not only inhibits side reactions, but also inhibits the photochlorination process to inhibit fluorotoluene, the self-luminous defluorination of p-fluorotrichlorobenzyl, and the high-temperature defluorination of p-fluorobenzoyl chloride in the distillation process, thereby further improving the purity of the synthesized p-fluorobenzoyl chloride to above 99.5. The aromatic nitro compound or its salt is specifically any one or two of nitrobenzene, dinitrobenzene, nitrotoluene, sodium nitrite or potassium nitrite, preferably potassium nitrite; the dosage is 0.1‰ to 1‰ of the mass of p-fluorotoluene, and the addition amount and time are strictly controlled to ensure that the effect of inhibiting the defluorination is achieved while ensuring the safety of the reaction process and the product, and has good practical value and important economic value.

The invention relates to the technical field of preparation of N-(2, 4-dinitrophenyl)-4-nitrobenzoyl aniline, in particular to a method for preparing a nitro amide compound by adopting a microreactor. The method for preparing the nitro amide compound comprises the following steps: introducing a sulfuric acid solution of 4-nitro-N-phenylbenzamide and a nitric acid aqueous solution into a microreactor, and reacting to obtain N-(2, 4-dinitrophenyl)-4-nitrobenzamide; the microreactor is provided with at least two reaction modules which are connected in series, and a sulfuric acid solution of 4-nitro-N-phenylbenzamide is divided into at least two strands which are respectively fed into a first reaction module of the microreactor and other reaction modules except the first reaction module; and the nitric acid aqueous solution enters the microreactor in a way of at least one stream. According to the method, the microreactor is used as a reaction carrier, the temperature in the reaction process is controllable, the raw material conversion rate is increased, and the residual amount of an intermediate N-4-nitro-(4-nitrophenyl) benzamide is reduced.

The invention discloses a method for reducing nitrides in waste acid based on a mixed dinitrobenzene preparation process, and relates to the technical field of mixed dinitrobenzene preparation. According to the method for reducing the nitrates in the waste acid based on the mixed dinitrobenzene preparation process, the mixed dinitrobenzene preparation process comprises first-stage nitration and second-stage nitration, and the waste acid is generated after the first-stage nitration; waste acid and benzene liquid are subjected to counter-current extraction in opposite flow directions through a filler layer, benzene is a continuous phase, and waste acid is a dispersed phase. According to the method, counter-current extraction is performed on the benzene liquid and the waste acid, the benzene liquid is a continuous phase, and the waste acid is a dispersed phase, so that nitrides in the waste acid are fully dissolved into the benzene liquid, the content of the nitrides in the waste acid after extraction is reduced, and the benzene liquid is continuously used as a raw material for preparing mixed dinitrobenzene.

A curcumin nanococrystal composition including curcumin, a coformer, and a stabilizer. The coformer may include at least one of 3,5-dinitrobenzoicacid, gentisic acid, phloroglucinol, 4,4-bipyridine, tartaric acid, citric acid, and gallic acid. The curcumin nanococrystal composition has a particle size less than 10 nm, and the curcumin has a water-solubility between 5 mg / ml and 20 mg / ml.

The invention discloses a chlorine-free synthesis method of 2, 4-dinitroanisole. The method comprises the following steps: by taking phenol as a raw material, carrying out first-stage and second-stage nitration in a microchannel or a tubular reactor to obtain 2, 4-dinitrophenol, then carrying out alkylation reaction on the 2, 4-dinitrophenol and an alkylation reagent under the action of an acid-binding agent, and carrying out filtration, rotary evaporation, precipitation, filtration, water washing and the like on a reaction solution to obtain a DNAN solid. According to the synthesis method, phenol is used as a raw material instead of chlorobenzene in a traditional process, chloride ions are not involved in the preparation process, corrosion to equipment is reduced, meanwhile, generation of a large amount of waste acid is avoided, and the three-waste treatment cost is reduced.

The invention relates to a detection method, in particular to a method for detecting aldehyde impurities in polysorbate 20. According to the method, interference caused by the purity of 2, 4-dinitrophenylhydrazine is avoided, derivatization of a reference substance is performed by adopting a method synchronously operating with a test sample, eight aldehyde ketone substances can be detected at the same time, and compared with literature methods, the method is high in specificity, good in precision, high in accuracy, simple and easy to implement and high in operability.

The application discloses a pyridazinyl dihydrazide compound, a preparation method thereof and application of the pyridazinyl dihydrazide compound in detection of nitrophenol, and a structure formula of the pyridazinyl dihydrazide compound is shown in the following formula: N,N'-di(4-methoxy-benzoyl)-6-chloro-pyridazinyl hydrazine prepared by the application is a fluorescent probe, and can be used for detecting low-concentration 2,4-dinitrophenol or 2,4,6-trinitrophenol in water.

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.

The invention relates to a method for preparing 1-chloro-2-methyl-3, 4-dinitrobenzene through microchannel-nitration reaction, which comprises the following steps: mixing nitric acid with sulfuric acid to obtain mixed acid, and mixing 2-chloro-6-nitrotoluene with sulfuric acid to obtain 2-chloro-6-nitrotoluene amp; the method comprises the following steps: inputting a mixed acid into a reaction cavity of a microchannel continuous flow reactor through a polytetrafluoroethylene constant-flux pump I, and amp 2-chloro-6-nitrotoluene; a sulfuric acid mixture is input into a reaction cavity of the microchannel continuous flow reactor through a polytetrafluoroethylene constant-flux pump II, and amp of 2-chloro-6-nitrotoluene is controlled; the method comprises the following steps: reacting a sulfuric acid mixture with mixed acid in a reaction cavity, obtaining a reaction product after the reaction is finished, and carrying out post-treatment on the reaction product to obtain the 1-chloro-2-methyl-3, 4-dinitrobenzene. According to the method, 2-chloro-6-nitrotoluene is used as a raw material, the micro-channel continuous flow reactor is adopted to prepare 1-chloro-2-methyl-3, 4-dinitrobenzene, the yield is high, the purity is high, the reaction is short, the selectivity is high, and few impurities are generated.

The application belongs to the technical field of near-infrared luminescence and ultrasonic treatment materials, discloses a kind of activatable acoustic power nano materials based on conjugated polymer and its preparation method and application, comprising the following steps: 2,6-di (trimethyl tin) -4,4-di (2-ethylhexyl) -dithiophene and cyclopentadiene, 4,7-dibromo-5,6-dinitrobenzo [c] [1,2,5] thiazole, catalyst tetra (triphenylphosphine) palladium are added into reaction tube, toluene is added, and the reaction product is settled with methanol under nitrogen protection, to obtain conjugated polymer;Degradable mesoporous silica is used to wrap to realize the water-soluble of molecule, and the corresponding activatable acoustic treatment reagent is obtained.The material disclosed in the application can be used for activatable acoustic dynamics treatment guided by near-infrared two-zone imaging, which helps to improve the specificity of tumor treatment, and mesoporous silica wrapping can also be used for drug loading and transport.

The invention discloses a preparation method of 2-amino-4-nitrophenol, belongs to the technical field of 2-amino-4-nitrophenol processing, and is used for solving the technical problems that in the prior art, the difficulty of recovering 2, 4-dinitrophenol from disperse blue wastewater is high, and the purity and the yield of 2-amino-4-nitrophenol need to be further improved. The method comprises the following steps: adding disperse blue production wastewater into a reaction kettle, stirring, and adding inorganic acid into the reaction kettle; according to the present invention, the adsorbent microspheres are prepared to adsorb the 2, 4-dinitrophenol in the disperse blue production wastewater, such that the process for recovering the 2, 4-dinitrophenol from the disperse blue wastewater is simplified, the purity and the regeneration rate of the regenerated 2, 4-dinitrophenol are improved, the composition of the catalyst solution and the reaction post-treatment method are optimized, and the 2, 4-dinitrophenol regeneration efficiency is improved. And the 2-amino-4-nitrophenol with high purity and high yield is prepared.

The invention discloses a bacteriostatic light cage for light-controlled rapid release of sulfadiazine, a preparation method and application thereof, and the bacteriostatic light cage is based on a light-controlled release system of a Sanger reagent, and realizes efficient space-time release and targeted antibiosis of SD. The light-operated bacteriostatic light cage capable of rapidly releasing sulfadiazine, disclosed by the invention, has sulfadiamidine-2, 4-dinitrobenzene derivative # imgabs0 # with a structure as shown in a formula SD-Py-N < + >

The invention discloses a eutectic of omeprazole and 3, 5-dinitrobenzoic acid, the molar ratio of omeprazole to 3, 5-dinitrobenzoic acid is 1: 1, and compared with omeprazole, the eutectic has higher stability, in-vivo absorption speed and onset speed.

The invention discloses a flavonol-based fluorescent probe for continuously detecting hydrogen sulfide and hypochlorous acid as well as a preparation method and application of the flavonol-based fluorescent probe. The flavonol-based fluorescent probe is 3-(2, 4-dinitrophenoxy)-7-(4-(diphenylamino) phenyl)-2-(4-(thiomorpholinophenyl) chromone, and the structural formula of the flavonol-based fluorescent probe is shown in the specification. According to the invention, 7-(4-(diphenylamino) phenyl)-3-hydroxy-2-(4-thiomorpholinophenyl) chromone is used as an initial raw material, and the 7-(4-(diphenylamino) phenyl)-3-hydroxy-2-(4-thiomorpholinophenyl) chromone and 2, 4-dinitrofluorobenzene are subjected to nucleophilic substitution reaction to obtain the compound 3-(2, 4-dinitrophenoxy)-7-(4-(diphenylamino) phenyl)-2-(4-(thiomorpholinophenyl) chromone. The compound is firstly subjected to selective thiolysis reaction under the action of hydrogen sulfide, the fluorescence color of a solution of the compound is changed from colorless to bright orange under the irradiation of ultraviolet light with the wavelength of 365 nm, then hypochlorous acid is continuously added into the solution, and the compound can be further subjected to specific oxidation reaction with the hypochlorous acid, so that the compound can be obtained. And the fluorescence color of the solution is changed from bright orange to bright cyan. Therefore, the compound can be used as a fluorescent probe for continuously detecting hydrogen sulfide and hypochlorous acid, has the advantages of low detection limit, high response speed, good light stability, wide pH application range and the like, and shows a good application prospect.

The present invention provides novel 2,4-dinitrophenol (DNP) derivatives and prodrugs thereof as modulators of mitochondrial function. The present invention also provides pharmaceutical compositions comprising the compounds of the present invention and methods for using the same to treat various diseases and conditions associated with or related to mitochondrial dysfunction (e.g., obesity, diabetes, insulin resistance, liver disease, heart or kidney failure, neurodegenerative diseases, and aging-related diseases, including but not limited to sarcopenia, osteoporosis, etc.).

The invention belongs to the technical field of synthesis of medicines and spices, and particularly relates to a synthesis method of trans-2-octenal. The synthesis method comprises the following steps: carrying out isomerization reaction on 1-octylene-3-alcohol under the catalytic action of 3, 4-dinitrobenzoic acid to obtain a trans-2-octylene-1-alcohol intermediate; the preparation method comprises the following steps: preparing trans-2-octenal from trans-2-octylene-1-alcohol under the oxidation action of m-chloroiodobenzene, 4-hydroxy-TEMPO (4-hydroxy-2, 2, 6, 6-tetramethylpiperidine nitroxide free radical) and peracetic acid, and further preparing the trans-2-octenal from the trans-2-octylene-1-alcohol. The preparation method is mild in reaction condition, simple to operate and free of expensive reagents or catalysts.

The invention discloses an unsymmetrical dimethylhydrazine detection method based on a 2, 4-dinitrobenzaldehyde chromogenic reaction, a reagent and a sensing film, and belongs to the field of dangerous chemical detection, the embodiment of the invention further provides the unsymmetrical dimethylhydrazine detection method based on the 2, 4-dinitrobenzaldehyde chromogenic reaction, a to-be-detected sample is in contact with an absorption liquid, and the absorption liquid is detected through the unsymmetrical dimethylhydrazine detection method based on the 2, 4-dinitrobenzaldehyde chromogenic reaction. Observing whether a color change from yellow to brownish red appears; the absorption liquid comprises 2, 4-dinitrobenzaldehyde, an acidic medium and a solvent. The existence of unsymmetrical dimethylhydrazine is judged by observing whether the color change from yellow to brownish red appears or not and observing the color depth or the size of a color change area. According to the method, the unsymmetrical dimethylhydrazine as low as 1 ppm in a gas phase and as low as 0.1% in a liquid phase can be subjected to rapid and distinct yellow-to-brown yellow chromogenic reaction, and common interference such as 50 ppm ammonia gas can be effectively inhibited in an acidic environment.

The invention discloses a preparation method and application of a selenium-containing asymmetric small molecule acceptor material, and belongs to the technical field of organic solar cell materials. In order to solve the problem that the photoelectric conversion efficiency (PCE) reported by most selenium-containing SMAs-based binary OSCs still stays between 17% and 18% at present, the invention provides a selenium-containing asymmetric small molecule acceptor material which takes quinoxaline as a core unit, asymmetric selenophen as a unit structure and an electron withdrawing group structure at the tail end. The preparation method comprises the following steps: in a nitrogen atmosphere, taking 4, 7-dibromo-5, 6-dinitrobenzo [c] [1, 2, 5] thiadiazole as a raw material, and carrying out a Stille coupling reaction, a Vismeier-Haack reaction and a Knoevenagel condensation reaction, so as to obtain the 4, 7-dibromo-5, 6-dinitrobenzo [c] [1, 2, 5] thiadiazole derivative. According to the invention, the molecular structure of the selenium-containing SMAs is accurately adjusted, so that the synthesized small molecule receptors AQX-2F-SSe and AQX-2F-SeS have high open-circuit voltage which is more than 0.9 V, and the AQX-2F-SeS has high photoelectric conversion efficiency PCE which is equal to 18.2%.