54 results about "Oleum" patented technology

Methods and associated production plants are disclosed for producing concentrated oleum or sulfur trioxide therefrom with high purity, and particularly with minimal sulfur dioxide. The methods involve use of a single contact, single absorption sulfuric acid plant operating under an unconventional set of parameters including: reacting sulfur and high purity oxygen in a combustion reactor to form sulfur dioxide at a concentration between 11.5 and 20% by volume and with an atypical oxygen to sulfur dioxide molar ratio ≥ 1; atypically catalytically converting > 96% by volume of the sulfur dioxide to sulfur trioxide in a contact apparatus; and atypically recycling > 95% by volume of the total gases from an absorption apparatus to the combustion reactor. Concentrated oleum with < 300 ppm dissolved sulfur dioxide can desirably be produced with sulfur utilization ≥ 80% using a smaller, cost-effective sulfuric acid plant. The co-production of unnecessary sulfuric acid can also be reduced.

The invention belongs to the field of inorganic chemical industry, and particularly relates to a method and a system for efficiently utilizing a phosphate fertilizer byproduct, the method comprises the following steps: carrying out acidolysis on fluosilicic acid with the concentration of more than or equal to 45% wt and concentrated sulfuric acid to generate a mixed solution of silicon tetrafluoride gas and fluorosulfonic acid; the mass ratio of the fluosilicic acid to the concentrated sulfuric acid is controlled to be 1: (4-15); pyrolyzing the obtained fluorosulfonic acid to generate dilute sulphuric acid, hydrogen fluoride and water vapor, forming 98% concentrated sulphuric acid from part of dilute sulphuric acid and fuming sulphuric acid, drying hydrogen fluoride to obtain crude hydrogen fluoride gas, and condensing and rectifying to obtain anhydrous hydrogen fluoride; the rest dilute sulphuric acid is partially compounded and then returned for acidolysis, and the rest dilute sulphuric acid is used for producing white carbon black and flows back to a wet-process phosphoric acid system; and circularly absorbing the obtained silicon tetrafluoride gas by using secondary concentrated fluosilicic acid to obtain fluosilicic acid with the mass concentration of more than or equal to 45%, recycling the fluosilicic acid for acidolysis reaction, and modifying the concentrated by-product silicon dioxide to obtain the high-activity white carbon black. The problems of energy consumption and cost are solved, and efficient circulation and poly-generation of fluorine and silicon resources are achieved in the whole process.

The invention relates to a method for removing cyclohexane in a low-molecular brominated polystyrene recovery solvent, which comprises the following steps: adding the recovery solvent containing cyclohexane and dichloromethane into a reaction bottle, and then adding a certain amount of fuming sulfuric acid; stirring and reacting for a period of time at a certain reaction temperature; adding water for quenching, standing for layering, washing an organic layer to be neutral, and standing for layering; and rectifying the organic layer, and collecting corresponding fractions. The used fuming sulfuric acid contains excessive sulfur trioxide, the sulfonation capacity is higher, cyclohexane is sulfonated to generate sulfonic acid group cyclohexane, then the sulfonic acid group cyclohexane is removed through water washing, the removal rate is high, the operation is convenient and fast, the cost is low, and the method is suitable for industrial production.

The invention discloses a method for producing SO3, which comprises the following steps: carrying out combustion reaction on sulfur and first oxygen-containing gas, and outputting SO2-containing first mixed gas; the first mixed gas and second oxygen-containing gas are subjected to a catalytic oxidation reaction, and second mixed gas containing SO3 is obtained; carrying out first fuming sulfuric acid absorption treatment on the second mixed gas to obtain third mixed gas and second fuming sulfuric acid; circulating and returning the third mixed gas to be mixed with the sulfur and the first oxygen-containing gas; performing separation treatment on the second fuming sulfuric acid to obtain third fuming sulfuric acid and SO3 gas; and mixing the third fuming sulfuric acid with the first fuming sulfuric acid, and carrying out absorption treatment on the second mixed gas. The method can meet the practical requirements that the SO3 product is produced, but sulfuric acid is not produced or sulfuric acid is produced as little as possible.

An integrated process for co-production of phosphorus pentafluoride (PF5) and fluorosulfonic acid (HSO3F) in high yield and purity through a single reaction step is provided. The method comprises reacting a first reagent comprising an aqueous solution of hexafluorophosphoric acid (HPF6) and hydrofluoric acid (HF) with a second reagent comprising fuming sulfuric acid (H2SO4SO3), and recovering a product mixture comprising phosphorus pentafluoride (PF5) and fluorosulfonic acid (HSO3F).

The invention provides a preparation method of high-purity isosulfur blue, which comprises the following steps: by taking 2-chlorobenzaldehyde as a raw material, after sulfonation reaction of fuming sulfuric acid, adding calcium carbonate to convert excessive sulfuric acid into calcium sulfate precipitate, and filtering to remove the calcium sulfate precipitate, thereby reducing inorganic salt residues in an intermediate I; carrying out substitution reaction on the intermediate I under the action of sodium sulfite and sodium hydrogen sulfite, adding a calcium chloride solution after the reaction to enable sulfite to form calcium sulfite precipitate, and carrying out filtration, vacuum concentration and methanol pulping to obtain a high-purity intermediate II; the intermediate II reacts with N, N-diethylaniline to generate an intermediate III, then the intermediate III is oxidized by silver oxide to generate an isosulfur blue silver salt, sodium carbonate is added to directly convert the silver salt into a sodium salt form, and a high-purity isosulfur blue finished product is obtained through ethyl acetate crystallization. According to the method, inorganic salt residues are remarkably reduced, the product purity and yield are improved, meanwhile, the technological process is simplified, the solvent usage amount is reduced, operation is safe and environmentally friendly, and industrial production is facilitated.

The application discloses a multi-stage fuming sulfuric acid absorption tower and a process method for absorbing sulfur trioxide by using the fuming sulfuric acid absorption tower. The multi-stage fuming sulfuric acid absorption tower comprises a primary absorption assembly and a secondary absorption assembly. The primary absorption assembly is provided with a first containing cavity. A first acid distributor is arranged in the first containing cavity and is arranged close to the upper wall surface of the first containing cavity and used for spraying acid liquid into the first containing cavity. The primary absorption assembly is provided with a flue gas inlet communicated with the first containing cavity. The secondary absorption assembly is arranged above the primary absorption assembly. The secondary absorption assembly is provided with a second containing cavity. The second containing cavity is communicated with the first containing cavity and used for receiving flue gas from the first containing cavity. A second acid distributor is arranged close to the upper wall surface of the second containing cavity and used for spraying acid liquid into the second containing cavity. The upper end of the secondary absorption assembly is provided with a flue gas outlet communicated with the second containing cavity. In this way, the sulfur trioxide absorption rate can be improved, and the product purity can be ensured.

This invention relates to the field of flame retardant chemical synthesis technology, and discloses ethylene bis(tetrabromophthalimide) and its preparation method and applications. The method includes reacting phthalic anhydride and ethylenediamine in an aqueous medium at a controlled mass ratio of 3.0-5.5:1 to obtain an intermediate; reacting the intermediate with bromine in a fuming sulfuric acid medium, controlling the dropping temperature at 45-60℃ and the holding temperature at 130-150℃; and washing the reaction product followed by high-temperature heat treatment at 150-220℃ to constant weight. This invention effectively inhibits residual active amino groups and organic carbonization by strictly controlling the intermediate synthesis ratio and the temperature range of the bromination reaction. By utilizing high-temperature heat treatment, it thoroughly removes deep-seated acidic volatiles that cannot be removed by conventional drying, solving the problems of yellowing appearance, poor heat resistance, and easy corrosion of processing equipment in existing products. It is applicable to the field of flame-retardant engineering plastics.

The invention provides a cyclohexanone-oxime transposition process flow and a cyclohexanone-oxime transposition device for partitioned sulfuric acid concentration supply, which are used for partitioned supply and accurate control of sulfuric acid concentration in different stages of transposition reaction, in the transposition process flow, fuming sulfuric acid is proportionally distributed to a high-concentration acid channel and a low-concentration acid channel through an intelligent metering and acid adding module, and the high-concentration acid channel and the low-concentration acid channel are communicated with the high-concentration acid channel and the low-concentration acid channel; the high-concentration acid channel is used for a one-step transposition reactor of a one-step reaction zone of the two-step transposition process, the low-concentration acid channel is used for a two-step transposition reactor of a two-step reaction zone of the two-step transposition process, and in the transposition process flow, a multi-mode fuzzy self-adaptive prediction PID control algorithm is adopted, control modes are switched according to reaction stages, and the multi-mode fuzzy self-adaptive prediction PID control algorithm is adopted. The first-step reaction zone adopts high-precision temperature-acid concentration cascade control, and the second-step reaction zone adopts by-product prediction feedforward control; according to the invention, partitioned supply and accurate control of sulfuric acid concentration in the first-step reaction zone and the second-step reaction zone can be realized, the reaction efficiency and selectivity are improved, and acid consumption and by-product generation are reduced.

The present application belongs to the field of boron trifluoride production, and relates to a method for preparing boron trifluoride and its complex by continuous flow reaction. The method comprises the following steps: uniformly mixing boric acid with concentrated sulfuric acid, then adding oleum or continuously introducing sulfur trioxide gas to obtain an oleum solution of boric acid; introducing the obtained solution and anhydrous hydrogen fluoride gas into a continuous flow reactor at a uniform speed to obtain boron trifluoride gas; purifying and removing impurities from the boron trifluoride gas generated in the reaction; continuously introducing the purified boron trifluoride gas into a complexing solvent for a complexing reaction to obtain a boron trifluoride complex. The method uses a continuous flow reactor to react anhydrous hydrogen fluoride with the oleum solution of boric acid, so that the raw materials can be continuously and uniformly mixed, the reaction is rapid and complete, the process conditions are simplified, the sulfuric acid waste liquid can be recycled after treatment, and the method has economic advantages and process innovation, and is suitable for industrial production.

This invention proposes an environmentally friendly and efficient method for preparing aminosulfonic acid, belonging to the field of chemical technology. It includes: (1) sulfonation reaction; (2) crude product filtration; (3) dissolution and crystallization; and (4) drying and packaging. The reaction process of this invention features mild reaction conditions, short reaction time, and a yield exceeding 97%. The process, using fuming sulfuric acid and urea at a lower temperature, significantly reduces polluting components in the waste gas. It has many advantages, including simple operation, low cost, high yield, and greater environmental friendliness.

The utility model relates to the technical field of sulfur trioxide separation and evaporation, and discloses a sulfur trioxide production device, which aims to solve the problem in sulfur trioxide evaporation in the prior art, and comprises a fuming sulfuric acid storage tank, the fuming sulfuric acid storage tank is connected with a film evaporator, and the film evaporator is connected with a saturated steam or heat-conducting oil pipeline and a fuming acid pipeline. The top of the film evaporator is connected with a gaseous sulfur trioxide pipeline, the gaseous sulfur trioxide pipeline is connected with a condenser, the condenser is connected with a liquid sulfur trioxide tank, a swirler is arranged in the film evaporator and comprises a first-stage swirling vane arranged at the lower part in the film evaporator, and a second-stage swirling vane is arranged at the upper part in the film evaporator; the film evaporator is utilized to separate gas-phase sulfur trioxide from low-concentration fuming acid, so that the sulfur trioxide is evaporated quickly, the swirlers are arranged in the film evaporator, materials are prevented from being carried by gas, and the swirlers are arranged in an upper stage and a lower stage, so that the evaporation rate of the sulfur trioxide can be effectively improved.

This invention discloses a method for producing chromatographic grade cyclohexane, comprising the following steps: A) Taking cyclohexane as raw material, adding fuming sulfuric acid to the cyclohexane raw material, stirring and allowing it to stand, and then separating the cyclohexane; B) Adding pure water to the cyclohexane obtained in step A, stirring and allowing it to stand, and then separating the cyclohexane; C) Adding activated alumina and 10X molecular sieve to the cyclohexane obtained in step B, stirring and allowing it to stand, and then filtering; D) Distilling the cyclohexane obtained in step C to obtain chromatographic grade cyclohexane. This invention uses fuming sulfuric acid to remove impurities from the cyclohexane raw material, then washes it directly with pure water, followed by adsorption filtration using molecular sieves and alumina, and finally distillation to obtain chromatographic grade cyclohexane with optical properties meeting market customer requirements. The preparation process of this invention is not complex, the consumption of auxiliary agents is low, and the cost is within a controllable range, achieving the goal of industrial production of chromatographic grade cyclohexane with high optical properties.

The invention provides a process and a plant for the production of ε-caprolactam and crystalline ammonium sulfate in an industrial-scale plant, wherein the plant comprises a Beckmann rearrangement reaction section, an ammonium sulfate crystallization section, and one or more heat exchangers configured to transfer heat from the Beckmann rearrangement reaction section to the ammonium sulfate crystallization section and wherein the process comprises the steps of:a) feeding(i) cyclohexanone oxime and(ii) oleum and / or sulfuric acidto the Beckmann rearrangement reaction sectionb) reacting components (i) and (ii) in the Beckmann rearrangement reaction section to form a reaction mixture comprising ε-caprolactam, whereby heat of reaction is generated;c) discharging the reaction mixture comprising ε-caprolactam from the Beckmann rearrangement reaction section;d) removing partially or fully the heat of reaction generated in the Beckmann rearrangement reaction section by one or more heat exchangers configured to transfer heat from the Beckmann rearrangement reaction section;e) feeding an aqueous liquid comprising ammonium sulfate to the ammonium sulfate crystallization section;f) introducing heat into the ammonium sulfate crystallization section comprising the aqueous ammonium-sulfate-comprising liquid by one or more heat exchangers configured to transfer heat into the ammonium sulfate crystallization section;g) forming ammonium sulfate crystals by evaporative crystallization in the ammonium sulfate crystallization section;characterized in thath) the heat of reaction removed from the Beckmann rearrangement reaction section in step d) is at least partially or fully transferred to the ammonium sulfate crystallization section in step f).

The utility model discloses an efficient fuming sulfuric acid and washing acid mixing device which comprises an acid mixing tank filled with washing acid, the side end of the bottom of the acid mixing tank is fixedly connected with a pre-mixing assembly through a connecting guide pipe, a circulating pump is fixed on the connecting guide pipe, and the top of the pre-mixing assembly is fixedly connected with a fuming sulfuric acid input pipe. The bottom of the pre-mixing assembly is fixedly connected with the top of the acid mixing tank through a guide pipe, and the pre-mixing assembly can increase the mixing contact area of fuming sulfuric acid and washing acid, so that the contact area of the fuming sulfuric acid and the washing acid is increased through the baffling effect of the pre-mixing assembly, two acidic materials can be mixed more sufficiently, the mixing efficiency is improved, and the mixing effect is improved. And through the pre-mixing assembly, efficient mixing can be realized in a relatively small space, so that the occupied area of the whole device is reduced, and the device is more convenient to use.

The invention discloses a preparation device and method of a sulfonic acid monomer, and relates to the technical field of chemical engineering. The preparation method comprises the following steps: S1, pumping acrylonitrile and fuming sulphuric acid into a premixer for mixing; s2, the mixed liquid enters a heat exchanger to be heated, and the temperature is controlled to range from 15 DEG C to 20 DEG C; s3, the heated mixed liquid enters a first-stage dynamic tubular reactor, gasified isobutene is introduced from lower, middle and upper layers of gas inlet branch pipes at the same time, and the reaction temperature is 40-45 DEG C; s4, after the materials react in the first-stage dynamic tubular reactor for 3-7 min, the materials enter a second-stage dynamic tubular reactor, and the reaction temperature ranges from 45 DEG C to 50 DEG C; and S5, cooling, carrying out solid-liquid separation, and drying to obtain the product. By adopting the method disclosed by the invention, the continuous and stable preparation of the sulfonic acid monomer 2-acrylamido-2-methylpropanesulfonic acid can be realized, and compared with the traditional process, the reaction time is greatly shortened, and the product purity (without refining and washing) can reach 99% or above.

The invention relates to the production of methanol via the partial oxidation of methane using iodine(III) catalysts, which allow the reaction to be performed at low temperatures and pressures. Similar chemistry can be used to make methyl bisulfate from methane in the presence of oleum, and to make ethylene glycol via the partial oxidation of ethane.

The invention discloses a process for producing sulfamic acid by a solid-phase dilution method. The invention relates to a sulfamic acid production process by a solid phase dilution method. The process comprises the following steps: S1, preparing a pre-reaction material with the sulfuric acid concentration of 105.5%; s2, adding the pre-reaction material and urea into a pre-sulfonation reactor for reaction, enabling reaction liquid to overflow into the sulfonation reactor, and performing sulfonation reaction to obtain a liquid mixture; s3, carrying out immobilization on the liquid mixture through speed-adjustable centrifugal anti-spiral immobilization equipment, and feeding an obtained immobilization material into a dilution kettle; s4, adding mother liquor into the dilution kettle to dilute and adjust the viscosity of the material; and S5, performing solid-liquid separation on the liquid material with the adjusted viscosity to obtain a sulfamic acid crude product and dilute sulphuric acid, and performing crystallization purification on the sulfamic acid crude product to obtain sulfamic acid. The sulfamic acid production process is improved, excessive fuming sulphuric acid entering the dilution process in the reaction process is remarkably reduced, the generation of a new byproduct dilute sulphuric acid is reduced, and the production cost is reduced.

The invention discloses a method for preparing sodium 3-diphenylphosphinobenzenesulfonate, which belongs to the field of organic synthesis technology. Using triphenylphosphine as raw material, fluoroboric acid is added to 1,4-dioxane to obtain triphenylphosphine fluoroborate, which is then reacted with fuming sulfuric acid for monosulfonation, and sodium hydroxide is used to form a sodium salt to obtain sodium 3-diphenylphosphinobenzenesulfonate. This process has relatively few disulfonation by-products and the yield is increased to 73-78%, ensuring product purity and providing guarantee for large-scale production.

The invention relates to a preparation method of 4, 5-diaminobenzene-1, 3 disulfonic acid, which comprises the following steps: a, adding concentrated sulfuric acid into a container provided with a thermometer and a stirring device, controlling the temperature and slowly adding o-phenylenediamine to obtain a sulfuric acid solution of o-phenylenediamine; b, slowly dropwise adding fuming sulfuric acid into the sulfuric acid solution of o-phenylenediamine in the step a, carrying out heat preservation reaction, and cooling; c, pouring the product in the step b into an ice-water mixture, adding activated carbon, stirring, and filtering to remove the activated carbon to obtain a diluent; d, carrying out reduced pressure distillation, concentration and cooling on the diluent; e, cooling, stirring, filtering and taking a solid to obtain a 4, 5-diaminobenzene-1, 3 disulfonic acid crude product; and f, adding the crude product into an organic solvent, pulping, washing acid, stirring, filtering to obtain a solid, and drying to obtain the 4, 5-diaminobenzene-1, 3-disulfonic acid. The method has the advantages of mild reaction conditions, normal pressure reaction, high yield, easily available raw materials and simple process, can be directly obtained by one-step sulfonation, and is suitable for industrial production.

The present invention provides a method for preparing phosphorus pentafluoride with high purity and low waste acid, comprising the following steps: (1) mixing hydrogen fluoride and polyphosphoric acid in an HPF6 synthesis kettle for reaction to obtain a mixed solution containing hexafluorophosphoric acid and water; (2) pumping the mixed solution into a fluorine gas stripping tower or an anhydrous sodium sulfate drying tower to remove water in the mixed solution by the fluorine gas stripping tower or the anhydrous sodium sulfate drying tower; (3) pumping the mixed solution into a mixed acid kettle, and simultaneously pumping in fuming sulfuric acid to further remove water in the mixed solution; (4) pumping the dehydrated material in the mixed acid kettle into a gas generating tower, heating the gas generating tower to decompose hexafluorophosphoric acid into gaseous PF5 and HF; the gas phase in the gas generating tower enters a rectifying tower after condensation, and phosphorus pentafluoride is obtained through rectification. The present invention improves the reaction yield and significantly shortens the reaction time required, and the new process significantly reduces the usage amount of fuming sulfuric acid, thereby significantly reducing the generation of waste concentrated sulfuric acid.

The invention provides a filtrate reducer and an oil-based drilling fluid as well as a preparation method and application of the filtrate reducer and the oil-based drilling fluid. The preparation method of the filtrate reducer comprises the following steps: mixing acrylonitrile, isobutene and acetone, heating and stirring for a first reaction, and dropwise adding fuming sulfuric acid in the heating and stirring process to obtain a first mixture; mixing N-alkyl acrylamide with the first mixture, and heating for second reaction to obtain a second mixture; dimethylaminoethyl methacrylate and the second mixture are mixed and heated for a third reaction, and a third mixture is obtained; ethyl benzene, carbon tetrachloride and the third mixture are mixed and heated for a fourth reaction, and a fourth mixture is obtained; and extracting and washing the fourth mixture with absolute ethyl alcohol to obtain a white floccule, namely the filtrate reducer. The oil-based drilling fluid comprises an oil phase, bentonite, the filtrate reducer provided by the invention, a flow pattern regulator, a weighting agent and sodium hydroxide. The oil-based drilling fluid provided by the invention has good high-temperature drop filtration performance and is suitable for drilling of deep wells and ultra-deep wells.

The application relates to the field of flame-retardant materials, and particularly discloses a preparation process of ethylene bis-tetrabromophthalimide with high thermal stability; the preparation process of ethylene bis-tetrabromophthalimide with high thermal stability comprises the following specific steps: phenolic anhydride and ethylenediamine are mixed in water, heated to react, centrifuged, dried to obtain an intermediate; the intermediate is mixed with bromine, fuming sulfuric acid and a catalyst to obtain a reaction solution, heated to react, deacidified, washed with water and dried to prepare ethylene bis-tetrabromophthalimide; the catalyst is a composite of ferric chloride and iodine; the ethylene bis-tetrabromophthalimide intermediate is synthesized by phenolic anhydride and ethylenediamine, and then bromination reaction is carried out, so that the instantaneous intense heat release caused by excessively high local bromine concentration is reduced, the escape of HBr and the loss of bromine are reduced, and the purity of the product is improved.

The invention discloses a system for flexibly preparing nitrate ester. The system comprises a Meilan acid storage tank, a fuming sulfuric acid storage tank, a first acid mixing ejector, a second acid mixing ejector, a first acid cooler, a second acid cooler, a polyhydric alcohol storage tank, a spraying nitrator, a coil pipe cooler, a kettle type continuous overflow nitrator, a centrifugal separator, a first dynamic washing separator and a second dynamic washing separator. The device comprises a first dynamic washing separator, a second dynamic washing separator, a third dynamic washing separator, a jet conveyor, a jet conveying water tank, a nitrate finished product temporary storage tank, a wastewater curved channel device, a nitrate-containing waste acid temporary storage tank, a flow meter, a gear pump, a three-way valve A, a three-way valve B, a three-way valve C and a three-way valve D, according to the system for preparing the nitrate ester, the nitrate ester can be prepared by selecting a spraying nitration process or a kettle type continuous overflow nitration process according to the characteristics of the nitrate ester.

The invention discloses a production process of deuterated sulphuric acid-d2, and belongs to the technical field of fine chemical engineering. In the production process of the deuterated sulphuric acid-d2 provided by the invention, the deuterated sulphuric acid-d2 is obtained by utilizing the reaction of the sulfur trioxide gas and the heavy water, meanwhile, the sulfur trioxide gas is firstly mixed with the argon before the reaction, and the argon is used as an inert carrier, so that the concentration of the sulfur trioxide gas can be effectively diluted, and violent reaction caused by local excessive heat release when the sulfur trioxide gas is in contact with the heavy water is avoided; and the introduction rate of the sulfur trioxide gas can be accurately controlled by adjusting the argon flow. In addition, the addition amount of the sulfur trioxide gas is not deliberately controlled to be excessive during the reaction, the deuterated fuming sulphuric acid is conveniently obtained firstly, then the deuterated sulphuric acid-d2 with the target concentration is obtained through dilution treatment in cooperation with nuclear magnetic resonance hydrogen spectrum detection, the technological process can be greatly simplified, and the deuterated sulphuric acid-d2 product with the accurate concentration can be obtained.

The invention discloses a 5-fluoro-2, 4-dinitro-3-(trifluoromethyl) aniline compound, which is prepared by the following method: reacting 3, 5-difluorotrifluoromethyl benzene at the high temperature of 160 DEG C by using fuming sulphuric acid and sodium nitrate as nitrating agents for 6 hours, cooling, separating out by using ice water after the temperature is reduced to room temperature, filtering, washing and drying to obtain 1, 5-difluoro-2, 4-dinitro-3-(trifluoromethyl) aniline, and separating out 1, 5-difluoro-2, 4-dinitro-3-(trifluoromethyl) aniline from the 1, 5-difluoro-2, 4-dinitro-3-(trifluoromethyl) aniline to obtain 1, 5-difluoro-2, 4-dinitro-3-(trifluoromethyl) aniline. The catalyst is 2, 4-dinitro-3-(trifluoromethyl) benzene. The preparation method comprises the following steps: dissolving 1, 5-difluoro-2, 4-dinitro-3-(trifluoromethyl) benzene in tetrahydrofuran, slowly dropwise adding an ammonia water solution, and naturally volatilizing to obtain the 5-fluoro-2, 4-dinitro-3-(trifluoromethyl) aniline (PFDNTN). The 5-fluoro-2, 4-dinitro-3-(trifluoromethyl) aniline prepared by the invention has a proper melting point (100 DEG C), and is relatively high in decomposition rate (322 DEG C), and the impact sensitivity is not lower than 40J; and the friction sensitivity is not lower than 360 N. The detonation velocity is 7066 m s <-1 >, and the detonation pressure is 24.65 Gpa, which is superior to that of TNT. And the explosive is expected to become a casting carrier explosive for replacing TNT.

The utility model discloses a single-tower production system for fuming sulfuric acid, and belongs to the technical field of sulfuric acid production equipment. The device comprises a first-stage fuming sulfuric acid tower, and a bottom discharge port of the first-stage fuming sulfuric acid tower is sequentially connected with a first-stage fuming sulfuric acid circulating tank and a first-stage fuming sulfuric acid cooler through pipelines to form closed-loop circulation; a sulfur trioxide gas inlet is formed in the side part of the first-stage tower, and the tower is filled with ceramic filler so as to improve the gas-liquid contact efficiency. In addition, a redundant second-stage fuming sulfuric acid tower is additionally arranged and connected with a tail gas outlet of the first-stage cooler through a pipeline, the height of a filler layer in the tower is reduced, and an acid mist trapping mechanism is additionally arranged and used for emergency starting and acid mist backflow under the abnormal working condition. Through main operation of the single tower, standby of the redundant secondary tower, pipeline interconnection optimization and filler structure adjustment, the purposes of energy conservation and consumption reduction are achieved, meanwhile, the system resistance is reduced, the operation process is simplified, and the production safety is improved.

The invention relates to the technical field of preparation of sulfur trioxide, and discloses a production method of liquid sulfur trioxide, which comprises the following steps: conveying fuming sulfuric acid in a fuming sulfuric acid storage tank to a first-stage preheater, exchanging heat with acid from a film evaporator, heating by flowing through a second-stage preheater, entering the film evaporator, and evaporating and separating to obtain the liquid sulfur trioxide. Gas-phase sulfur trioxide obtained through evaporation and separation enters a condenser to be condensed, a fuming sulfuric acid solution obtained through evaporation and separation flows back to the fuming sulfuric acid storage tank after flowing to the first-stage preheater and exchanging heat with the fuming sulfuric acid in the fuming sulfuric acid storage tank to be cooled, and then the fuming sulfuric acid solution flows back to the fuming sulfuric acid storage tank and is circulated again. In addition, the evaporation efficiency of sulfur trioxide is improved, and the evaporation rate reaches up to 37.2%. According to the invention, the energy consumption of the nicotinic acid circulation amount is reduced, the treatment efficiency of fuming sulfuric acid is improved, the heat exchange coefficient is high, and the risk of short operation period caused by corrosion due to excessive evaporation caused by long working condition retention time and local overheating of an original circulation evaporation system is reduced.

The utility model relates to liquid level measurement technical field, concretely relates to the storage tank device for the fuming sulfuric acid measurement, including the first storage tank for loading fuming sulfuric acid, the top of first storage tank is connected with tail gas absorber, first storage tank and tail gas absorber are communicated through first connecting pipeline, install first suction pump on first connecting pipeline, the tail gas absorber includes the casing, the inside of casing forms the tail gas absorption chamber for purifying flue gas, the bottom of casing is provided with the gas inlet hole, the gas inlet hole is communicated with first connecting pipeline, the top of casing is provided with the exhaust hole that supplies the flue gas after purifying and exports, the top of first storage tank is installed and is used for detecting the radar liquid level meter group of fuming sulfuric acid liquid level.

The invention relates to the field of production of chemical products, in particular to a preparation method of high-purity phosphorus pentafluoride. The preparation method of the high-purity phosphorus pentafluoride provided by the invention comprises the following steps: mixing apatite and hydrofluoric acid, and carrying out first reaction to generate phosphoric acid; adding fuming sulfuric acid, carrying out second reaction to generate crude phosphorus pentafluoride gas, and purifying to obtain the phosphorus pentafluoride, the purified reagent comprises an ether solvent and sterically hindered amine. The phosphorite is directly used as the raw material to prepare the phosphorus pentafluoride, so that the process route from phosphorite to the phosphorus pentafluoride is remarkably shortened, and the utilization rate of phosphorus is increased. Meanwhile, a mixed reagent of an ether solvent and sterically hindered amine is adopted during purification, and the Lewis acidity of phosphorus pentafluoride is far higher than that of silicon tetrafluoride, so that the complexing ability of phosphorus pentafluoride and the ether solvent is higher, and phosphorus pentafluoride and silicon tetrafluoride are efficiently separated by utilizing the difference of solubility; and the sterically hindered amine selectively forms a precipitate with silicon tetrafluoride, so that the separation degree of phosphorus pentafluoride and silicon tetrafluoride is further improved, and a high-purity phosphorus pentafluoride product is obtained.